In JoVE (1)

Other Publications (92)

Articles by Adilia Warris in JoVE

Other articles by Adilia Warris on PubMed

Contamination of Hospital Water with Aspergillus Fumigatus and Other Molds

Clinical Infectious Diseases : an Official Publication of the Infectious Diseases Society of America. Apr, 2002  |  Pubmed ID: 11915011

Multidrug Resistance in Aspergillus Fumigatus

The New England Journal of Medicine. Dec, 2002  |  Pubmed ID: 12501236

Aspergillus Fumigatus Evades Immune Recognition During Germination Through Loss of Toll-like Receptor-4-mediated Signal Transduction

The Journal of Infectious Diseases. Jul, 2003  |  Pubmed ID: 12854089

Peritoneal macrophages from Toll-like receptor (TLR) 4-deficient ScCr mice produced less tumor necrosis factor, interleukin (IL)-1alpha, and IL-1beta than did macrophages of control mice, when stimulated with conidia, but not with hyphae, of Aspergillus fumigatus, a finding suggesting that TLR4-mediated signals are lost during germination. This hypothesis was confirmed by use of a TLR4-specific fibroblast reporter cell line (3E10) that responded to the conidia, but not to the hyphae, of A. fumigatus. In contrast, macrophages from TLR2-knockout mice had a decreased production of proinflammatory cytokines in response to both Aspergillus conidia and Aspergillus hyphae, and these results were confirmed in 3E10 cells transfected with human TLR2. In addition, Aspergillus hyphae, but not Aspergillus conidia, stimulated production of IL-10 through TLR2-dependent mechanisms. In conclusion, TLR4-mediated proinflammatory signals, but not TLR2-induced anti-inflammatory signals, are lost on Aspergillus germination to hyphae. Therefore, phenotypic switching during germination may be an important escape mechanism of A. fumigatus that results in counteracting the host defense.

Molecular Epidemiology of Aspergillus Fumigatus Isolates Recovered from Water, Air, and Patients Shows Two Clusters of Genetically Distinct Strains

Journal of Clinical Microbiology. Sep, 2003  |  Pubmed ID: 12958232

There has been an increase in data suggesting that besides air, hospital water is a potential source of transmission of filamentous fungi, and in particular Aspergillus fumigatus. Molecular characterization of environmental and clinical A. fumigatus isolates, collected prospectively during an 18-month period, was performed to establish if waterborne fungi play a role in the pathogenesis of invasive aspergillosis. Isolates recovered from water (n = 54) and air (n = 21) at various locations inside and outside the hospital and from 15 patients (n = 21) with proven, probable, or possible invasive aspergillosis were genotyped by amplified fragment length polymorphism analysis. Based on genomic fingerprints, the environmental A. fumigatus isolates could be grouped into two major clusters primarily containing isolates recovered from either air or water. The genotypic relatedness between clinical and environmental isolates suggests that patients with invasive aspergillosis can be infected by strains originating from water or from air. In addition, 12 clusters with genetically indistinguishable or highly related strains were differentiated, each containing two to three isolates. In two clusters, clinical isolates recovered from patients matched those recovered from water sources, while in another cluster the clinical isolate was indistinguishable from one cultured from air. This observation might open new perspectives in the development of infection control measures to prevent invasive aspergillosis in high-risk patients. The genetic variability found between airborne and waterborne A. fumigatus strains might prove to be a powerful tool in understanding the transmission of invasive aspergillosis and in outbreak control.

Preventing Fungal Infections in Chronic Granulomatous Disease

The New England Journal of Medicine. Sep, 2003  |  Pubmed ID: 14503544

Cytokine Release in Healthy Donors and Patients with Chronic Granulomatous Disease Upon Stimulation with Aspergillus Fumigatus

Scandinavian Journal of Infectious Diseases. 2003  |  Pubmed ID: 14514148

The release of tumour necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6) and IL-10 upon stimulation with non-viable conidia and hyphal fragments from Aspergillus fumigatus was investigated in an ex vivo whole-blood model. In healthy volunteers, high numbers of conidia (between 10(6) and 3 x 10(8)/ml) induced a moderate release of TNF-alpha and IL-6. Hyphal fragments (2.5 x 10(5)/ml) were more potent in stimulating the release of these pro-inflammatory cytokines. Although some IL-10 release was observed upon stimulation with either conidia or hyphal fragments, it was not significantly different from that in unstimulated controls. In comparison, in whole blood obtained from 4 patients with chronic granulomatous disease (CGD), a high release of pro-inflammatory cytokines together with a significantly higher IL-10 release than in the healthy controls was seen after stimulation with A. fumigatus. In conclusion, A. fumigatus can trigger the release of pro-inflammatory cytokines in a human whole-blood system, which is likely to be central to the activation of antifungal defence mechanisms. In contrast, A. fumigatus stimulates a higher release of anti-inflammatory cytokines in CGD patients, which may suggest that a dysregulation between pro- and anti-inflammatory cytokines contributes to the increased susceptibility to invasive aspergillosis in this patient group.

Bifidobacterium Lipoteichoic Acid and False ELISA Reactivity in Aspergillus Antigen Detection

Lancet (London, England). Jan, 2004  |  Pubmed ID: 14751710

A major difficulty with the detection of circulating galactomannan, a cell-wall polysaccharide released by Aspergillus sp during growth, in the serodiagnosis of invasive aspergillosis is the occurrence of false-positive ELISA results, especially in neonates and infants. On the basis of molecule similarity, we postulate that a lipoteichoic acid of Bifidobacterium sp can act as epitope for the monoclonal antibody used in the ELISA. The neonatal gut is heavily colonised with Bifidobacterium sp and these bacteria or their lipoteichoic acid might cause ELISA reactivity with serum after translocation because of immaturity of the intestinal mucosa. If our hypothesis is correct, we might find a method to discriminate between false-positive and true-positive ELISA results and thereby prevent unnecessary pre-emptive treatment of patients.

Bifidobacterial Lipoglycan As a New Cause for False-positive Platelia Aspergillus Enzyme-linked Immunosorbent Assay Reactivity

Journal of Clinical Microbiology. Aug, 2005  |  Pubmed ID: 16081932

We previously hypothesized that a lipoglycan of Bifidobacterium bifidum subsp. pennsylvanicum cross-reacts with the Platelia Aspergillus (PA) enzyme-linked immunosorbent assay (ELISA) based on the presence of galactofuranosyl epitopes in the cell wall (M. A. S. H. Mennink-Kersten, R. R. Klont, A. Warris, H. J. M. Op den Camp, and P. E. Verweij, Lancet 363:325-327, 2004). We tested this hypothesis by testing bacterial suspensions of different bifidobacterial species and other gram-positive and -negative bacteria with the PA ELISA, which is used to detect circulating galactomannan for the serodiagnosis of invasive aspergillosis. Furthermore, neonatal fecal samples were enumerated for bifidobacteria by fluorescence in situ hybridization (FISH) and tested for PA ELISA reactivity. All bifidobacteria, except B. infantis and B. adolescentis, showed reactivity 6- to 600-fold higher compared to the controls (i.e., Micrococcus luteus and Propionibacterium freudenreichii, which contain a cell wall lipomannan). Eggerthella lenta showed a 25-fold-higher reactivity. ELISA reactivity was clearly shown to be associated with bacterial lipoglycans containing a beta-1,5-galactofuranosyl chain. All neonatal feces showed PA ELISA reactivity and associated numbers of bifidobacteria. Since high concentrations of bifidobacteria are present in the human gut, these bacteria or excreted lipoglycan may cause false serum PA ELISA reactivity in selected patient groups, especially neonates.

Cytokine Responses and Regulation of Interferon-gamma Release by Human Mononuclear Cells to Aspergillus Fumigatus and Other Filamentous Fungi

Medical Mycology. Nov, 2005  |  Pubmed ID: 16396246

There is substantial evidence that the production of proinflammatory cytokines is important in host resistance to invasive aspergillosis. Knowledge of the host response towards other filamentous fungi is scarce, as most studies have focused on Aspergillus fumigatus. In addition, interferon-gamma (IFNgamma) plays a crucial role in the control of invasive aspergillosis, but little is known about the regulation of IFNgamma after stimulation of mononuclear cells by A. fumigatus. Cytokine responses to four different Aspergillus spp., Scedosporium prolificans, and a Rhizopus oryzae strain were compared for their ability to induce the release of tumour necrosis factor-alpha (TNFalpha) and interleukin(IL)-6 by human monocytes. S. prolificans induced significantly more TNFalpha and IL-6 release compared to A. fumigatus, while the various Aspergillus spp. induce comparable levels of these cytokines. By using specific cytokine inhibitors we were able to show that endogenous IL-1, but not IL-18 and TNFalpha was required for IFNgamma and IL-10 release upon stimulation with A. fumigatus hyphae, whereas conidia induced IFNgamma stimulation is independent of these cytokines.

Measurement of Neutrophil Membrane CD64 and HLA-Dr in a Patient with Abdominal Sepsis

The Journal of Infection. Jul, 2006  |  Pubmed ID: 16253335

A patient with abdominal sepsis, had both intra and extracellular bacteria in a blood smear, and high levels of neutrophil membrane CD64 and HLA-Dr. Intracellular bacteria are only observed in the terminal phase of a sepsis. Our patient recovered, suggesting that a high expression of neutrophil CD64 is indicative for a good prognosis.

Legionella Pneumophila in Commercial Bottled Mineral Water

FEMS Immunology and Medical Microbiology. Jun, 2006  |  Pubmed ID: 16706786

Sixty-eight commercial bottled mineral waters (64 brands, 68 different 'best-before dates') were tested for the presence of bacteria and fungi. Six samples were Legionella antigen positive and six were Legionella pneumophila PCR positive. Two samples were both Legionella antigen and L. pneumophila PCR positive. Legionella cultures were negative. Although the PCR might have detected only dead Legionella cells, the PCR has been described to detect specifically viable but not culturable (VBNC) L. pneumophila cells as well. Whether VBNC bacteria may be present in bottled mineral waters and the risk for infection this may pose for severely immunocompromised patients should be investigated.

Human Metapneumovirus: an Important Cause of Acute Respiratory Illness

Advances in Experimental Medicine and Biology. 2006  |  Pubmed ID: 16802634

1,3-beta-D-glucan in Patients Receiving Intravenous Amoxicillin-clavulanic Acid

The New England Journal of Medicine. Jun, 2006  |  Pubmed ID: 16807428

Refractory Severe Intestinal Vasculitis Due to Henoch-Schönlein Purpura: Successful Treatment with Plasmapheresis

Acta Paediatrica (Oslo, Norway : 1992). May, 2006  |  Pubmed ID: 16825146

Intestinal Perforations in Children on Peritoneal Dialysis

Peritoneal Dialysis International : Journal of the International Society for Peritoneal Dialysis. Nov-Dec, 2006  |  Pubmed ID: 17047240

Pharmacokinetics of Two Generic Fixed-dose Combinations for HIV-infected Children (Pedimune Baby & Pedimune Junior) Are Similar to the Branded Products in Healthy Adults

The Journal of Antimicrobial Chemotherapy. Jan, 2007  |  Pubmed ID: 17071953

Cipla Pharmaceuticals have developed generic fixed-dose combinations of stavudine, lamivudine and nevirapine for HIV-infected children (Pedimune Baby and Junior). We determined the pharmacokinetic profiles of stavudine, lamivudine and nevirapine in Pedimune and compared these with the branded products.

Plasma Concentrations of the HIV-protease Inhibitor Lopinavir Are Suboptimal in Children Aged 2 Years and Below

Antiviral Therapy. 2007  |  Pubmed ID: 17668553

Lopinavir/ritonavir (LPV/r) has been licensed for the treatment of HIV-infected children >6 months in the US and >2 years in the EU. Limited LPV paediatric pharmacokinetic data are available. We studied LPV pharmacokinetics to determine whether the recommended dose (230/57.5 mg/m2 twice daily) results in optimal LPV exposure in all age groups. Virological efficacy was a secondary objective.

The Effect of Antifungal Agents and Human Monocytes on in Vitro Galactomannan Release by Aspergillus Spp. in Liquid Culture Medium

APMIS : Acta Pathologica, Microbiologica, Et Immunologica Scandinavica. Dec, 2007  |  Pubmed ID: 18184406

Invasive pulmonary aspergillosis is increasing in incidence in immunosuppressed patients. Diagnosis of this infection is problematic, relying on clinical suspicion and computerized tomography of the thorax and sinuses. An assay capable of detecting the fungal cell wall component galactomannan (GM) as a sign of Aspergillus infection is in use in patients with hematological malignancies. The aim of this study was to investigate the release of GM during growth of two medically important species, Aspergillus fumigatus and Aspergillus terreus, in liquid medium, including interaction with fluconazole, amphotericin B, liposomal amphotericin B and itraconazole, as well as human monocytes. Our results showed that for both species, amphotericin B deoxycholate, liposomal amphotericin B and itraconazole reduced the concentrations of GM to very low levels at the lowest doses tested (1, 3 and 4 microg/L, respectively). High doses of fluconazole had negligible effect on GM release by A. terreus, as expected. However, fluconazole at 128 microg/L increased GM concentrations released by A. fumigatus without reduction in visible growth. Co-incubation with human monocytes had no significant effect on GM release. The effects of antifungal agents on GM release may have diagnostic implications.

Children with HIV Are Not Small Adults: What is Different in Pharmacology?

Current Opinion in HIV and AIDS. Sep, 2007  |  Pubmed ID: 19372919

The pharmacokinetics of antiretroviral drugs are highly variable among HIV-infected children. This review describes pharmacokinetic processes in children and recent pharmacokinetic data in children with HIV. The general lack of pharmacokinetic data and the potential role of therapeutic drug monitoring are discussed.

Immunohistochemical Features of Cutaneous Granulomas in Primary Immunodeficiency Disorders: a Comparison with Cutaneous Sarcoidosis

Journal of Cutaneous Pathology. May, 2008  |  Pubmed ID: 18201241

Cutaneous granulomas can occur in patients with a primary immunodeficiency disorder. In some cases, an infectious cause cannot be revealed. The pathogenesis of these granulomas still remains to be elucidated. The aim of this study was to study differences or overlap between these rare granulomas and sarcoidosis-related granulomas.

Improved Detection of Circulating Aspergillus Antigen by Use of a Modified Pretreatment Procedure

Journal of Clinical Microbiology. Apr, 2008  |  Pubmed ID: 18287324

Detection of circulating galactofuranose (galf) antigens, including galactomannan (GM), by the Platelia Aspergillus (PA) enzyme-linked immunosorbent assay (ELISA) is an important tool in the early diagnosis of invasive aspergillosis (IA). We used a modified pretreatment technique (MT) on consecutive negative PA ELISA plasma samples from IA patients in order to improve the detection of the fungal components present. Plasma samples (52) were collected from healthy donors, and 174 plasma samples with a galactomannan index (GMI) below 0.5 were collected from 25 unclassifiable and 23 IA patients. The PA ELISA reactivity of pretreated samples was determined before (conventional technique [CT]) and after (MT) filtration using a Microcon filter with a 50-kDa cutoff (Millipore). For the MT, the sensitivity of the PA ELISA increased from 42.9% (CT) to 78.6% (MT) using a cutoff for the GMI of 1.5 in the probable and proven group, whereas specificity slightly decreased from 98.7% to 96.1% in the control group. The 10-fold concentration step increased the GMI as high as 121-fold. The MT resulted not only in positive reactivity in samples that tested negative with the CT but also in the earlier detection of antigen by 2 to 17 days.

Amphotericin B-deoxycholate Overdose Due to Administration Error in Pediatric Patients

Medical Mycology. Mar, 2008  |  Pubmed ID: 18324499

Due to the similarity of their generic names, the use of amphotericin B-deoxycholate and liposomal amphotericin B could cause confusion in daily practice. We report two cases of amphotericin B-deoxycholate overdose in infants due to administration errors which raises the issue that the use of this antifungal agent should be questioned because of its severe side effects.

Emericella Quadrilineata As Cause of Invasive Aspergillosis

Emerging Infectious Diseases. Apr, 2008  |  Pubmed ID: 18394273

We noted a cluster of 4 cases of infection or colonization by Emericella spp., identified by sequence-based analysis as E. quadrilineata. Sequence-based analysis of an international collection of 33 Emericella isolates identified 12 as E. nidulans, all 12 of which had previously been identified by morphologic methods as E. nidulans. For 12 isolates classified as E. quadrilineata, only 6 had been previously identified accordingly. E. nidulans was less susceptible than E. quadrilineata to amphotericin B (median MICs 2.5 and 0.5 mg/L, respectively, p<0.05); E. quadrilineata was less susceptible than E. nidulans to caspofungin (median MICs, 1.83 and 0.32 mg/L, respectively, p<0.05). These data indicate that sequence-based identification is more accurate than morphologic examination for identifying Emericella spp. and that correct species demarcation and in vitro susceptibility testing may affect patient management.

Disseminated Aspergillosis in an Adolescent with Acute Lymphoblastic Leukemia

Pediatric Blood & Cancer. Sep, 2008  |  Pubmed ID: 18478572

Disseminated aspergillosis in immunocompromised patients has a mortality rate of almost 100%. Despite the development of new antifungal agents, the outcome of disseminated aspergillosis has only improved slightly, particular in patients with central nervous system (CNS) involvement. The use of combination antifungal therapy might improve the dismal outcome of disseminated aspergillosis. We describe a critically ill adolescent with acute lymphoblastic leukemia who was successfully treated with voriconazole and caspofungin for disseminated aspergillosis with involvement of the lung, brain and thyroid gland.

Gastrointestinal Zygomycosis Due to Rhizopus Microsporus Var. Rhizopodiformis As a Manifestation of Chronic Granulomatous Disease

Medical Mycology. Aug, 2008  |  Pubmed ID: 18608916

A case of gastrointestinal zygomycosis in a 10-month-old boy with chronic granulomatous disease (CGD) is presented. Zygomycetes are an uncommon cause of fungal disease in CGD patients and gastrointestinal zygomycosis has not been previously described in individuals with CGD. To improve outcome, a timely and correct diagnosis is of utmost importance.

Therapeutic Drug Monitoring of Voriconazole

Therapeutic Drug Monitoring. Aug, 2008  |  Pubmed ID: 18641555

Voriconazole is a triazole antifungal developed for the treatment of life-threatening fungal infections in immunocompromised patients. The drug, which is available for both oral and intravenous administration, has broad-spectrum activity against pathogenic yeasts, dimorphic fungi, and opportunistic molds. Voriconazole has a nonlinear pharmacokinetic profile with a wide inter- and intraindividual variety. This variability is caused by many factors such as gender, age, genotypic variation, liver dysfunction, the presence of food, and so on. Another important factor influencing voriconazole's pharmacokinetic profile is drug-drug interactions with CYP450 inhibitors as well as inducers. Variability in plasma concentrations, as a result of the previously mentioned aspects, may lead to variability in efficacy or toxicity. Determination of plasma concentrations is indicated in situations to guide dosing and to individualize and improve the treatment options resulting in better therapeutic outcome or fewer side effects. In this article, we review factors influencing voriconazole pharmacokinetic profile, the data supporting exposure-effect and exposure-toxicity relationships, review the gaps in current knowledge, which make broad recommendations for therapeutic drug monitoring difficult for voriconazole, provide the indications in which therapeutic drug monitoring is reasonable based on currently available data (eg, children), and outline the ways in which this problem could be solved. We provide a summary of the problem so that further research can be conducted to address this are of clinical need.

Therapeutic Drug Monitoring of Voriconazole in a Child with Invasive Aspergillosis Requiring Extracorporeal Membrane Oxygenation

Therapeutic Drug Monitoring. Dec, 2008  |  Pubmed ID: 19057370

We describe a patient with invasive pulmonary aspergillosis on extracorporeal membrane oxygenation therapy in which therapeutic drug monitoring and individualization of therapy by measuring voriconazole plasma concentrations were performed.

Modulation of Toll-like Receptor 2 (TLR2) and TLR4 Responses by Aspergillus Fumigatus

Infection and Immunity. May, 2009  |  Pubmed ID: 19204090

Toll-like receptor (TLR)-based signaling pathways in the host may be modulated by pathogens during the course of infection. We describe a novel immunomodulatory mechanism in which Aspergillus fumigatus conidia induce attenuation of TLR2- and TLR4-mediated interleukin (IL)-6 and IL-1beta proinflammatory responses in human mononuclear cells with suppression of IL-1beta mRNA transcription. Background TLR2 and TLR4 mRNA transcription was not influenced. A. fumigatus conidia induced TLR2 internalization and uptake into the phagosome with a resultant decrease in surface receptor expression. A. fumigatus hyphae, on the other hand, selectively downregulated the TLR4-mediated response. These novel immunosuppressive effects may facilitate the invasiveness of A. fumigatus.

Nuclear Factor-{kappa}B is Not Essential for NADPH Oxidase Activity in Neutrophils from Anhidrotic Ectodermal Dysplasia Patients

Blood. May, 2009  |  Pubmed ID: 19470438

[Azole-resistant Invasive Aspergillosis]

Nederlands Tijdschrift Voor Geneeskunde. 2009  |  Pubmed ID: 20051169

Invasive aspergillosis caused by medical triazole-resistant Aspergillus fumigatus is described in two patients. A 31-year-old male with chronic granulomatous disease developed pulmonary aspergillosis despite itraconazole prophylaxis. A. fumigatus was cultured from the lung and was found to be azole-resistant. The patient was successfully treated with caspofungin. The second patient was a 13-year-old boy with acute lymphoid leukaemia. He developed pulmonary aspergillosis that failed to respond to voriconazole therapy. The infection spread to the brain and an azole-resistant isolate was cultured from a lung biopsy. Despite a switch to liposomal amphotericin B in combination with caspofungin, the infection progressed and the patient died. Azole-resistance has emerged in A. fumigatus and may develop through the treatment of patients. However, there is evidence that in the Netherlands, resistance might be emerging through fungal exposure to azole fungicides. Azole resistance further complicates the management of invasive aspergillosis and should be considered as cause for treatment failure.

Aspergillus Fumigatus Conidial Melanin Modulates Host Cytokine Response

Immunobiology. Nov, 2010  |  Pubmed ID: 19939494

Melanin biopigments have been linked to fungal virulence. Aspergillus fumigatus conidia are melanised and are weakly immunogenic. We show that melanin pigments on the surface of resting Aspergillus fumigatus conidia may serve to mask pathogen-associated molecular patterns (PAMPs)-induced cytokine response. The albino conidia induced significantly more proinflammatory cytokines in human peripheral blood mononuclear cells (PBMC), as compared to melanised wild-type conidia. Blocking dectin-1 receptor, Toll-like receptor 4 or mannose receptor decreased cytokine production induced by the albino but not by the wild type conidia. Moreover, albino conidia stimulated less potently, cytokine production in PBMC isolated from an individual with defective dectin-1, compared to the stimulation of cells isolated from healthy donors. These results suggest that β-glucans, but also other stimulatory PAMPs like mannan derivatives, are exposed on conidial surface in the absence of melanin. Melanin may play a modulatory role by impeding the capability of host immune cells to respond to specific ligands on A. fumigatus.

Human Immunodeficiency Virus and Tuberculosis Coinfection in Children: Challenges in Diagnosis and Treatment

The Pediatric Infectious Disease Journal. Oct, 2010  |  Pubmed ID: 20651637

The burden of childhood tuberculosis (TB) is influenced by the human immunodeficiency virus (HIV) epidemic and this dangerous synergy affects various aspects of both diseases; from pathogenesis and the epidemiologic profile to clinical presentation, diagnosis, treatment, and prevention. HIV-infected infants and children are at increased risk of developing severe forms of TB. The TB diagnosis is complicated by diminished sensitivity and specificity of clinical features and diagnostic tools like the tuberculin skin test and chest x-ray. Although alternative ways of pulmonary sampling and the development of interferon-γ assays have shown to lead to some improvement of TB diagnosis in HIV-infected children, new diagnostic tools are urgently needed. Coadministration of anti-TB treatment and antiretroviral drugs induces severe complications, and this highlights the need to define optimal treatment regimens. Practical implementation of these regimens in TB control programs should be combined with isoniazid preventive therapy in TB-exposed HIV-infected children. The risk of severe complications after Bacille Calmette-Guérin vaccination of HIV-infected children emphasizes the need for new nonviable vaccines. This article reviews the current status of pediatric HIV-TB coinfection with specific emphasis on the diagnosis and treatment.

Aspergillus Species Intrinsically Resistant to Antifungal Agents

Medical Mycology. Apr, 2011  |  Pubmed ID: 20662634

Polyphasic taxonomy has had a major impact on the species concept of the genus Aspergillus. New sibling species have been described that exhibit in vitro susceptibility profiles that differ significantly from that of Aspergillus fumigatus. While acquired resistance is an emerging problem in A. fumigatus, non-A. fumigatus Aspergillus species may be intrinsically resistant to specific classes of antifungal agents. Minimum inhibitory concentrations of amphotericin B and azoles for some of the non-A. fumigatus Aspergillus species are elevated compared to A. fumigatus. Furthermore, the clinical presentation and evolution of invasive infections caused by these species may differ from that commonly observed for A. fumigatus. As the role of the newly identified Aspergillus species in causing invasive aspergillosis remains unclear, surveillance networks that incorporate sequence-based identification of clinical isolates are needed to determine the species distribution, the clinical disease and outcome of patients with invasive aspergillosis. Preclinical and clinical studies are needed to further improve the methods for in vitro susceptibility testing and to investigate the impact of elevated MICs on antifungal drug efficacy.

Human Leukocytes Kill Aspergillus Nidulans by Reactive Oxygen Species-independent Mechanisms

Infection and Immunity. Feb, 2011  |  Pubmed ID: 21078850

Invasive aspergillosis is a major threat for patients suffering from chronic granulomatous disease (CGD). Although Aspergillus fumigatus is the most commonly encountered Aspergillus species, the presence of A. nidulans appears to be disproportionately high in CGD patients. The purpose of this study was to investigate the involvement of the NADPH oxidase and the resulting reactive oxygen species (ROS) in host defense against fungi and to clarify their relationship toward A. nidulans. Murine CGD alveolar macrophages (AM) and polymorphonuclear leukocytes (PMN) and peripheral blood mononuclear cells (PBMC) from healthy controls and CGD patients were challenged with either A. fumigatus or A. nidulans. Analysis of the antifungal effects of ROS revealed that A. nidulans, in contrast to A. fumigatus, is not susceptible to ROS. In addition, infection with live A. nidulans did not result in any measurable ROS release. Remarkably, human CGD PMN and PBMC and murine CGD AM were at least equipotent at arresting conidial germination compared to healthy controls. Blocking of the NADPH oxidase resulted in significantly reduced damage of A. fumigatus but did not affect A. nidulans hyphae. Furthermore, the microbicidal activity of CGD PMN was maintained toward A. nidulans but not A. fumigatus. In summary, antifungal resistance to A. nidulans is not directly ROS related. The etiology of A. nidulans infections in CGD cannot be explained by the simple absence of the direct microbicidal effect of ROS. In vivo, the NADPH oxidase is a critical regulator of innate immunity whose unraveling will improve our understanding of fungal pathogenesis in CGD.

Impact of Therapeutic Drug Monitoring of Voriconazole in a Pediatric Population

The Pediatric Infectious Disease Journal. Jun, 2011  |  Pubmed ID: 21127454

Voriconazole trough concentrations more than 1 mg/L are associated with a higher likelihood of success. It is unknown whether these trough concentrations are reached with the current recommended pediatric dosing schedule. We retrospectively analyzed the results of our therapeutic drug monitoring service for voriconazole in 18 children treated at our children's hospital. Thirty-nine voriconazole plasma concentrations were measured. In 44% of patients, the first voriconazole concentration was below the target. Dose adjustment eventually resulted in plasma concentrations within the predefined target range in all patients. Given the high proportion of patients with subtherapeutic concentrations, monitoring plasma concentrations should be performed routinely in pediatric patients receiving voriconazole.

A Twice Daily Posaconazole Dosing Algorithm for Children with Chronic Granulomatous Disease

The Pediatric Infectious Disease Journal. Sep, 2011  |  Pubmed ID: 21772229

Posaconazole (PSZ) may be an attractive alternative for antifungal prophylaxis in children with chronic granulomatous disease. Experience with PSZ in pediatric patients is limited, and no specific dose recommendations exist. A twice daily dosing algorithm based on allometric scaling (body-weight based) for PSZ results in adequate exposure and appears to be safe in children with chronic granulomatous disease.

"Mycobacterium Tilburgii" Infection in Two Immunocompromised Children: Importance of Molecular Tools in Culture-negative Mycobacterial Disease Diagnosis

Journal of Clinical Microbiology. Dec, 2011  |  Pubmed ID: 22012013

"Mycobacterium tilburgii" is a nontuberculous mycobacterium that cannot be cultured by current techniques. It is described as causing disseminated disease in adults. We present the first cases of disseminated disease in 2 immunocompromised children. This paper stresses the importance of molecular techniques for correct mycobacterial identification and guidance to immunological diagnosis.

B-cell Replication History and Somatic Hypermutation Status Identify Distinct Pathophysiologic Backgrounds in Common Variable Immunodeficiency

Blood. Dec, 2011  |  Pubmed ID: 22042693

Common variable immunodeficiency disorder (CVID) is the most prevalent form of primary idiopathic hypogammaglobulinemia. Identification of genetic defects in CVID is hampered by clinical and immunologic heterogeneity. By flow cytometric immunophenotyping and cell sorting of peripheral B-cell subsets of 37 CVID patients, we studied the B-cell compartment at the B-cell subset level using the κ-deleting recombination excision circle assay to determine the replication history and the Igκ-restriction enzyme hot-spot mutation assay to assess the somatic hypermutation status. Using this approach, 5 B-cell patterns were identified, which delineated groups with unique replication and somatic hypermutation characteristics. Each B-cell pattern reflected an immunologically homogenous patient group for which we proposed a different pathophysiology: (1) a B-cell production defect (n = 8, 18%), (2) an early peripheral B-cell maturation or survival defect (n = 4, 11%), (3) a B-cell activation and proliferation defect (n = 12, 32%), (4) a germinal center defect (n = 7, 19%), and (5) a postgerminal center defect (n = 6, 16%). The results of the present study provide for the first time insight into the underlying pathophysiologic background in 5 immunologically homogenous groups of CVID patients. Moreover, this study forms the basis for larger cohort studies with the defined homogenous patient groups and will facilitate the identification of underlying genetic defects in CVID.

Q Fever: Still More Queries Than Answers

Advances in Experimental Medicine and Biology. 2011  |  Pubmed ID: 22125041

Q fever is a worldwide zoonosis, caused by C. burnetii. Infection usually occurs through inhalation of infected aerosols. The reservoir mainly consists of dairy cattle. Clinical symptoms of acute Q fever are non-specific and resemble a mild flu-like illness. Children often present with gastrointestinal symptoms and rash. Rarely, chronic infection develops. This is usually manifested as endo-carditis, vascular infection and, in children, osteomyelitis. Diagnosis is based on serology and nucleic acid amplification (PCR). Doxycycline is the treatment of choice for acute infection. An alternative for young children and pregnant women is cotrimoxazole. Chronic infection requires long term treatment usually with doxycycline combined with hydroxychloroquine.

Infection with Multiple Viruses is Not Associated with Increased Disease Severity in Children with Bronchiolitis

Pediatric Pulmonology. Apr, 2012  |  Pubmed ID: 21901859

The clinical relevance of parallel detection of multiple viruses by real-time polymerase chain reaction (RT-PCR) remains unclear. This study evaluated the association between the detection of multiple viruses by RT-PCR and disease severity in children with bronchiolitis.

High Prevalence of Acute Respiratory Tract Infections Among Warao Amerindian Children in Venezuela in Relation to Low Immunization Coverage and Chronic Malnutrition

The Pediatric Infectious Disease Journal. Mar, 2012  |  Pubmed ID: 22094640

Higher prevalence rates of acute respiratory tract infections (ARTIs) have been described in Australian and Canadian indigenous populations than in nonindigenous age-matched counterparts. Few studies on ARTIs in South American indigenous populations have been published. We performed a cross-sectional survey to describe the prevalence of upper respiratory tract infections and acute lower respiratory tract infections (ALRTIs) and associations with malnutrition and immunization status.

Favorable Outcome of Chronic Disseminated Candidiasis in Four Pediatric Patients with Hematological Malignancies

Medical Mycology. Apr, 2012  |  Pubmed ID: 22103343

Four children were diagnosed with chronic disseminated candidiasis (CDC) during treatment for hematological malignancies. All presented with persistent fever, not responsive to broad-spectrum antibiotics, abdominal distension and hepatosplenomegaly. Two children needed artificial ventilation because of respiratory insufficiency. The time between onset of neutropenic fever and diagnosis of CDC ranged from 20-49 days. Ultrasound and computed tomography failed to demonstrate CDC during the neutropenic phase. All children needed a liver or spleen biopsy to establish the diagnosis of CDC. Three of four patients continued chemotherapy during treatment for the fungal infection. All patients had a favorable outcome, both in terms of the invasive Candida infections, as well as their underlying malignancies.

Low Interleukin-17A Production in Response to Fungal Pathogens in Patients with Chronic Granulomatous Disease

Journal of Interferon & Cytokine Research : the Official Journal of the International Society for Interferon and Cytokine Research. Apr, 2012  |  Pubmed ID: 22191467

Patients with chronic granulomatous disease (CGD) cannot produce reactive oxygen species (ROS) due to a genetic defect in the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase system. Dysregulation of the L-tryptophan metabolism in mice with defects in NADPH oxidase, resulting in overproduction of interleukin (IL)-17, has been proposed to link ROS defects with hyperinflammation and susceptibility to pulmonary aspergillosis. In this study, we assessed the L-tryptophan metabolism and cytokine profiles in response to fungal pathogens in CGD patients. Peripheral blood mononuclear cells (PBMCs) from CGD patients showed increased production of IL-6, tumor necrosis factor-α, and interferon-γ upon stimulation with Aspergillus or Candida species, while IL-17A production was strikingly low compared with healthy controls. Indoleamine 2,3-dioxygenase expression was similar in PBMCs and neutrophils from CGD patients compared with healthy controls. Conversion of L-tryptophan to L-kynurenine, as measured by high-performance liquid chromatography, did not differ between CGD patients and healthy controls. Moreover, adding L-kynurenine to the cell cultures did not suppress fungal-induced IL-17A production. Although PBMCs of CGD patients produced more proinflammatory cytokines after stimulation, IL-17A production was strikingly low in response to fungal pathogens when compared with healthy controls. In addition, cells from CGD patients did not display a defective L-tryptophan metabolism.

Presence of ATM Protein and Residual Kinase Activity Correlates with the Phenotype in Ataxia-telangiectasia: a Genotype-phenotype Study

Human Mutation. Mar, 2012  |  Pubmed ID: 22213089

Ataxia-telangiectasia (A-T) is an autosomal recessive neurodegenerative disorder with multisystem involvement and cancer predisposition, caused by mutations in the A-T mutated (ATM) gene. To study genotype-phenotype correlations, we evaluated the clinical and laboratory data of 51 genetically proven A-T patients, and additionally measured ATM protein expression and kinase activity. Patients without ATM kinase activity showed the classical phenotype. The presence of ATM protein, correlated with slightly better immunological function. Residual kinase activity correlated with a milder and essentially different neurological phenotype, absence of telangiectasia, normal endocrine and pulmonary function, normal immunoglobulins, significantly lower X-ray hypersensitivity in lymphocytes, and extended lifespan. In these patients, cancer occurred later in life and generally consisted of solid instead of lymphoid malignancies. The genotypes of severely affected patients generally included truncating mutations resulting in total absence of ATM kinase activity, while patients with milder phenotypes harbored at least one missense or splice site mutation resulting in expression of ATM with some kinase activity. Overall, the phenotypic manifestations in A-T show a continuous spectrum from severe classical childhood-onset A-T to a relatively mild adult-onset disorder, depending on the presence of ATM protein and kinase activity. Each patient is left with a tremendously increased cancer risk.

Importance of Neutropenia for Development of Invasive Infections at Various Phases of Treatment for Hemato-oncological Diseases in Children

Scandinavian Journal of Infectious Diseases. May, 2012  |  Pubmed ID: 22216875

Prolonged neutropenia in patients with acute myeloid leukemia (AML), relapsed acute lymphoblastic leukemia (r-ALL), myelodysplastic syndrome (MDS), and those receiving hematopoietic stem cell transplantation (HSCT), is a well-known risk factor for infectious complications. Few data are available about the incidence and etiology of infectious episodes during the total treatment period associated with a decreased immunity.

29th ESPID Annual Meeting in The Hague, the Netherlands

The Pediatric Infectious Disease Journal. Apr, 2012  |  Pubmed ID: 22418654

Inflammation in the Middle Ear of Children with Recurrent or Chronic Otitis Media is Associated with Bacterial Load

The Pediatric Infectious Disease Journal. Nov, 2012  |  Pubmed ID: 22668804

Viral upper respiratory tract infections have been described as an important factor in the development of otitis media (OM), although it is unclear whether they facilitate bacterial OM or can directly cause OM. To clarify the role of viral infections in OM, we compared the relative contribution of viruses and bacteria with the induction of inflammatory cytokine responses in the middle ear of children suffering from OM.

Use of MMP-8 and MMP-9 to Assess Disease Severity in Children with Viral Lower Respiratory Tract Infections

Journal of Medical Virology. Sep, 2012  |  Pubmed ID: 22825827

Matrix metalloproteinases (MMPs) play an important role in respiratory inflammatory diseases, such as asthma and chronic obstructive pulmonary disease. It was hypothesized that MMP-8 and MMP-9 may function as biological markers to assess disease severity in viral lower respiratory tract infections in children. MMP-8 and MMP-9 mRNA expression levels in peripheral blood mononuclear cells (PBMCs) and granulocytes obtained in both the acute and recovery phase from 153 children with mild, moderate, and severe viral lower respiratory tract infections were determined using real-time PCR. In addition, MMP-8 and MMP-9 concentrations in blood and nasopharyngeal specimens were determined during acute mild, moderate, and severe infection, and after recovery using ELISA. Furthermore, PBMCs and neutrophils obtained from healthy volunteers were stimulated with RSV, LPS (TLR4 agonist), and Pam3Cys (TLR2 agonist) in vitro. Disease severity of viral lower respiratory tract infections in children is associated with increased expression levels of the MMP-8 and MMP-9 genes in both PBMCs and granulocytes. On the contrary, in vitro experiments showed that MMP-8 and MMP-9 mRNA and protein expression in PBMCs and granulocytes is not induced by stimulation with RSV, the most frequent detected virus in young children with viral lower respiratory tract infections. These data indicate that expression levels of the MMP-8 and MMP-9 genes in both PBMCs and neutrophils are associated with viral lower respiratory tract infections disease severity. These observations justify future validation in independent prospective study cohorts of the usefulness of MMP-8 and MMP-9 as potential markers for disease severity in viral respiratory infections.

Aspergillus Nidulans and Chronic Granulomatous Disease: a Unique Host-pathogen Interaction

The Journal of Infectious Diseases. Oct, 2012  |  Pubmed ID: 22829648

Invasive fungal infections are a major threat for patients suffering from chronic granulomatous disease (CGD), a primary immunodeficiency caused by a defect in the nicotinamide adenine dinucleotide phosphate (NADPH)-oxidase. Interestingly, Aspergillus (Emericella) nidulans is the second most encountered mold in CGD patients, causing almost exclusively invasive infections in this specific host, and is characterized by its aggressive behavior. A proper diagnosis is complicated by the often mild clinical presentation, the low sensitivity of the currently used diagnostic tools, and the difficulties in accurate identification of the Emericella species. According to the hitherto accepted view on the role of the NADPH-oxidase in the innate host-defense pathway, the pathogenesis of A. nidulans in CGD cannot be explained. This synopsis covers the current understanding of invasive infections caused by A. nidulans in the CGD patient and is intended to direct further research by indicating gaps in our knowledge and to guide optimal management strategies.

Results from a Prospective, International, Epidemiologic Study of Invasive Candidiasis in Children and Neonates

The Pediatric Infectious Disease Journal. Dec, 2012  |  Pubmed ID: 22982980

Candida species are the third most common cause of pediatric health care-associated bloodstream infection in the United States and Europe. To our knowledge, this report from the International Pediatric Fungal Network is the largest prospective, multicenter observational study dedicated to pediatric and neonatal invasive candidiasis.

Reply: To PMID 21901859

Pediatric Pulmonology. Jun, 2013  |  Pubmed ID: 22811277

Diagnosis of Invasive Pulmonary Aspergillosis in Children with Bronchoalveolar Lavage Galactomannan

Pediatric Pulmonology. Aug, 2013  |  Pubmed ID: 22949309

Invasive pulmonary aspergillosis (IPA) is a life-threatening complication in immunocompromised patients. Early diagnosis and therapy improves outcome. Assessment of galactomannan (GM) in bronchoalveolar lavage (BAL) fluid is a proposed tool to diagnose IPA. Little is known about the diagnostic value of BAL GM in children.

Prevalence of Lipodystrophy in HIV-infected Children in Tanzania on Highly Active Antiretroviral Therapy

The Pediatric Infectious Disease Journal. Jan, 2013  |  Pubmed ID: 23038217

Highly active antiretroviral therapy (HAART) has been associated with lipodystrophy (LD) in adults but data are more limited for children. The purpose of this study was to determine the prevalence of and risk factors for LD in Tanzanian children receiving HAART by clinical assessment and to compare the results with anthropometric data.

CD4+ T-cell Counts and Interleukin-8 and CCL-5 Plasma Concentrations Discriminate Disease Severity in Children with RSV Infection

Pediatric Research. Feb, 2013  |  Pubmed ID: 23165450

Current tools to predict the severity of respiratory syncytial virus (RSV) infection might be improved by including immunological parameters. We hypothesized that a combination of inflammatory markers would differentiate between severe and mild disease in RSV-infected children.

Severe Phenotype of Severe Combined Immunodeficiency Caused by Adenosine Deaminase Deficiency in a Patient with a Homozygous Mutation Due to Uniparental Disomy

The Journal of Allergy and Clinical Immunology. Jul, 2013  |  Pubmed ID: 23260757

[Pertussis in Young Infants: a Dangerous Disease with Non-specific Signs]

Nederlands Tijdschrift Voor Geneeskunde. 2013  |  Pubmed ID: 23343739

Pertussis, or whooping cough, caused by Bordetella pertussis, still occurs despite vaccination. Most of the cases occurring in adolescents and adults are mild or have a subclinical course, but these patients can be a source of transmission to unvaccinated or partially vaccinated infants. Symptoms of infant pertussis are often not specific, but pertussis can be fatal. In this article, we present one case of unvaccinated twins who each presented with initial signs of a viral respiratory disease. Within a few days, each developed rapidly progressive respiratory failure complicated by refractory pulmonary hypertension due to malignant pertussis. Both patients died eventually. It is important for paediatricians, general practitioners, midwives and gynaecologists to be alert to coughing in their patients. More efficient vaccination strategies should be discussed to prevent both the transmission of B. pertussis and the occurrence of severe and fatal pertussis in young infants.

Microbial Profiling Does Not Differentiate Between Childhood Recurrent Acute Otitis Media and Chronic Otitis Media with Effusion

International Journal of Pediatric Otorhinolaryngology. Apr, 2013  |  Pubmed ID: 23369612

Otitis media (OM) is one of the most frequent diseases of childhood, with a minority of children suffering from recurrent acute otitis media (rAOM) or chronic otitis media with effusion (COME), both of which are associated with significant morbidity. We investigated whether the microbiological profiling could be used to differentiate between these two conditions.

Update on Antifungal Resistance in Children: Epidemiology and Recommendations

The Pediatric Infectious Disease Journal. May, 2013  |  Pubmed ID: 23376939

Favorable Outcome of Neonatal Cerebrospinal Fluid Shunt-associated Candida Meningitis with Caspofungin

Antimicrobial Agents and Chemotherapy. May, 2013  |  Pubmed ID: 23439643

Invasive Candida infections associated with medical devices are very difficult to cure without device removal. We present a case of neonatal cerebrospinal fluid shunt-associated Candida meningitis, in which removal of the device was precluded, that was successfully treated with caspofungin. Pharmacokinetic assessment of caspofungin concentrations in cerebrospinal fluid showed that exposure was adequate in the presence of a high systemic exposure. In complex cases of neonatal Candida infections involving medical devices, the addition of caspofungin might be beneficial.

Chloroquine Modulates the Fungal Immune Response in Phagocytic Cells from Patients with Chronic Granulomatous Disease

The Journal of Infectious Diseases. Jun, 2013  |  Pubmed ID: 23482646

Invasive aspergillosis is a major threat to patients with chronic granulomatous disease (CGD). Fungal pathogenesis is the result of a diminished antifungal capacity and dysregulated inflammation. A deficient NADPH-oxidase complex results in defective phagolysosomal alkalization. To investigate the contribution of defective pH regulation in phagocytes among patients with CGD during fungal pathogenesis, we evaluated the effect of the acidotropic, antimalarial drug chloroquine (CQ) on the antifungal capacity of polymorphonuclear cells (PMNs) and on the inflammatory response of peripheral blood mononuclear cells (PBMCs). Chloroquine exerted a direct pH-dependent antifungal effect on Aspergillus fumigatus and Aspergillus nidulans; it increased the antifungal activity of PMNs from patients with CGD at a significantly lower concentration, compared with the concentration for PMNs from healthy individuals; and decreased the hyperinflammatory state of PBMCs from patients with CGD, as observed by decreased tumor necrosis factor α and interleukin 1β release. Chloroquine targets both limbs of fungal pathogenesis and might be of great value in the clearance of invasive aspergillosis in patients with CGD.

Bacterial Respiratory Pathogens in Children with Inherited Immune and Airway Disorders: Nasopharyngeal Carriage and Disease Risk

The Pediatric Infectious Disease Journal. Apr, 2013  |  Pubmed ID: 23552676

Children with primary immunodeficiencies, sickle cell disease and cystic fibrosis are at risk to develop invasive bacterial infections caused by respiratory tract pathogens, in particular Streptococcus pneumoniae, Haemophilus influenzae and Staphylococcus aureus. This review article evaluates the role of nasopharyngeal colonization by these pathogens in the high prevalence of respiratory and invasive infections in children with inherited disorders affecting the immune system or the respiratory tract. We conclude that respiratory and invasive diseases that occur in children with primary immunodeficiencies or sickle cell disease are probably a result of increased nasopharyngeal colonization rates compared with healthy children. However, when the inherited disorder is characterized by local airway abnormalities such as in cystic fibrosis, enhanced nasopharyngeal colonization does not seem to play a major role in invasive disease risk. As the evidence for the role of nasopharyngeal colonization in disease risk in these specific patient groups partly comes from experimental studies and animal models, longitudinal studies in children are needed. Detailed understanding of the effect of colonization on the development of respiratory and invasive infections in children with primary immunodeficiencies, sickle cell disease or cystic fibrosis provides a justification for the selective introduction of vaccination and prophylactic antibiotic treatment. Recommendations for the use of (preventive) therapeutic strategies in these patient groups taking into account disease-specific immunologic mechanisms underlying colonization and disease are described.

Antibody Deficiency in Patients with Ataxia Telangiectasia is Caused by Disturbed B- and T-cell Homeostasis and Reduced Immune Repertoire Diversity

The Journal of Allergy and Clinical Immunology. May, 2013  |  Pubmed ID: 23566627

Ataxia telangiectasia (AT) is a multisystem DNA-repair disorder caused by mutations in the ataxia telangiectasia mutated (ATM) gene. Patients with AT have reduced B- and T-cell numbers and a highly variable immunodeficiency. ATM is important for V(D)J recombination and immunoglobulin class-switch recombination (CSR); however, little is known about the mechanisms resulting in antibody deficiency severity.

Invasive Fungal Infections in Patients with Chronic Granulomatous Disease

Advances in Experimental Medicine and Biology. 2013  |  Pubmed ID: 23654055

Invasive fungal infections are a major threat for chronic granulomatous disease (CGD) patients. The present study provides a comprehensive overview of published invasive fungal infections in the CGD host through an extensive review of epidemiological, clinical, diagnostic and therapeutic data. In addition to the often mild clinical presentation, the currently used diagnostics for invasive aspergillosis have low sensitivity in CGD patients and cannot be easily translated to this non-neutropenic host. Aspergillus fumigatus and A. nidulans are the most commonly isolated species. A. nidulans infections are seldom reported in other immunocompromised patients, indicating a unique interaction between this fungus and the CGD host. The occurrence of mucormycosis is mainly noted in the setting of treatment of inflammatory complications with immunosuppressive drugs. Candida infections are infrequently seen and do not cause mucocutaneous disease but do show an age-dependent clinical presentation. The CGD patient is susceptible to a wide range of fungal pathogens, indicating the need to determine the causative fungus, often by invasive diagnostics, to guide optimal and rational treatment. This review summarizes current understanding of invasive fungal infections in patients with CGD and will serve as a starting point to guide optimal treatment strategies and to direct further research aimed at improving outcomes.

Common Variable Immunodeficiency and Idiopathic Primary Hypogammaglobulinemia: Two Different Conditions Within the Same Disease Spectrum

Haematologica. Oct, 2013  |  Pubmed ID: 23753020

Patients with hypogammaglobulinemia who do not fulfill all the classical diagnostic criteria for common variable immunodeficiency (reduction of two immunoglobulin isotypes and a reduced response to vaccination) constitute a diagnostic and therapeutic dilemma, because information concerning the clinical and immunological characteristics of these patients with idiopathic primary hypogammaglobulinemia is not available. In 44 common variable immunodeficiency and 21 idiopathic primary hypogammaglobulinemia patients we determined the clinical phenotypes and performed flow cytometric immunophenotyping to assess the pathophysiological B-cell patterns and memory B-cell subset counts. Age-matched B-cell subset reference values of 130 healthy donors were generated. Severe pneumonia and bronchiectasis occurred at similar frequencies in idiopathic primary hypogammaglobulinemia and common variable immunodeficiency. Although IgG levels were only moderately reduced compared to common variable immunodeficiency, 12 of 21 idiopathic primary hypogammaglobulinemia patients required immunoglobulin replacement. Non-infectious disease-related clinical phenotypes (autoimmune cytopenia, polyclonal lymphocytic proliferation and persistent unexplained enteropathy) were exclusively observed in common variable immunodeficiency and were associated with early peripheral B-cell maturation defects or B-cell survival defects. T-cell dependent memory B-cell formation was more severely affected in common variable immunodeficiency. Furthermore, 14 of 21 idiopathic primary hypogammaglobulinemia patients showed normal peripheral B-cell subset counts, suggestive for a plasma cell defect. In conclusion, idiopathic primary hypogammaglobulinemia patients who do not fulfill all diagnostic criteria of common variable immunodeficiency have moderately decreased immunoglobulin levels and often a normal peripheral B-cell subset distribution, but still suffer from serious infectious complications.

Long-term Response to Combination Antiretroviral Therapy in HIV-infected Children in the Netherlands Registered from 1996 to 2012

AIDS (London, England). Oct, 2013  |  Pubmed ID: 23842124

To describe demographic and treatment characteristics of the Dutch vertically HIV-infected paediatric population from 1996 to 2012, and to investigate the long-term virological and immunological response to combination antiretroviral therapy (cART), with emphasis on the influence of age at cART initiation and initial CD4 cell counts.

[The Measles Are Here Again]

Nederlands Tijdschrift Voor Geneeskunde. 2013  |  Pubmed ID: 23965248

Since the vaccination of Dutch children against the measles through the National Immunisation Programme started in 1976, the incidence of measles has greatly decreased. Local epidemics do still occur, however; these are largely confined to minority groups of orthodox Protestants who object to vaccination on religious grounds. A local epidemic of the measles has been developing in the Netherlands since May of this year, predominantly within unvaccinated groups where the highly contagious virus can easily spread. We describe an unvaccinated 10-year-old boy with an uncomplicated case of the measles and an unvaccinated 9-year-old boy who developed encephalitis as a complication of the measles. From the waning of maternal antibodies until the first regular vaccination and where herd immunity is lacking, children are at risk of the measles. For this reason, an extra (age < 12 months) or early (12-14 months) vaccination is being offered during the current epidemic for all children aged 6 to 14 months who live in areas with low (< 90%) vaccination coverage.

Clinical Spectrum of LIG4 Deficiency is Broadened with Severe Dysmaturity, Primordial Dwarfism, and Neurological Abnormalities

Human Mutation. Dec, 2013  |  Pubmed ID: 24027040

DNA double-strand break repair via non-homologous end joining (NHEJ) is involved in recombination of immunoglobulin and T-cell receptor genes. Mutations in NHEJ components result in syndromes that are characterized by microcephaly and immunodeficiency. We present a patient with lymphopenia, extreme radiosensitivity, severe dysmaturity, corpus callosum agenesis, polysyndactily, dysmorphic appearance, and erythema, which are suggestive of a new type of NHEJ deficiency. We identified two heterozygous mutations in LIG4. The p.S205LfsX29 mutation results in lack of the nuclear localization signal and appears to be a null mutation. The second mutation p.K635RfsX10 lacks the C-terminal region responsible for XRCC4 binding and LIG4 stability and activity, and therefore this mutant might be a null mutation as well or have very low residual activity. This is remarkable since Lig4 knockout mice are embryonic lethal and so far in humans no complete LIG4 deficiencies have been described. This case broadens the clinical spectrum of LIG4 deficiencies.

[Borrelial Lymphocytoma]

Nederlands Tijdschrift Voor Geneeskunde. 2013  |  Pubmed ID: 24382037

Borrelial lymphocytoma is a relatively rare but typical presentation of Lyme disease. Predilection sites are the ears in children and chest/nipples in adults. It is treated like an erythema migrans and has a good prognosis.

Severe Infantile Bordetella Pertussis Pneumonia in Monozygotic Twins with a Congenital C3 Deficiency

European Journal of Pediatrics. Dec, 2014  |  Pubmed ID: 23963626

Bordetella pertussis or whooping cough is a vaccine-preventable disease that still remains a serious infection in neonates and young infants. We describe two young infants, monozygotic twins, with a severe B. pertussis pneumonia of whom one needed extracorporeal membrane oxygenation. Diagnostic work-up of unexplained hematuria and proteinuria during the illness revealed low serum complement component 3 (C3) levels. During follow-up, C3 levels remained low (400-600 mg/L). Extensive analysis of the persistent low C3 levels revealed an unknown heterozygous mutation in the C3 gene in both siblings and their mother. This C3 mutation in combination with the specific virulence mechanisms of B. pertussis probably contributed to the severe disease course in these cases.

Extreme Growth Failure is a Common Presentation of Ligase IV Deficiency

Human Mutation. Jan, 2014  |  Pubmed ID: 24123394

Ligase IV syndrome is a rare differential diagnosis for Nijmegen breakage syndrome owing to a shared predisposition to lympho-reticular malignancies, significant microcephaly, and radiation hypersensitivity. Only 16 cases with mutations in LIG4 have been described to date with phenotypes varying from malignancy in developmentally normal individuals, to severe combined immunodeficiency and early mortality. Here, we report the identification of biallelic truncating LIG4 mutations in 11 patients with microcephalic primordial dwarfism presenting with restricted prenatal growth and extreme postnatal global growth failure (average OFC -10.1 s.d., height -5.1 s.d.). Subsequently, most patients developed thrombocytopenia and leucopenia later in childhood and many were found to have previously unrecognized immunodeficiency following molecular diagnosis. None have yet developed malignancy, though all patients tested had cellular radiosensitivity. A genotype-phenotype correlation was also noted with position of truncating mutations corresponding to disease severity. This work extends the phenotypic spectrum associated with LIG4 mutations, establishing that extreme growth retardation with microcephaly is a common presentation of bilallelic truncating mutations. Such growth failure is therefore sufficient to consider a diagnosis of LIG4 deficiency and early recognition of such cases is important as bone marrow failure, immunodeficiency, and sometimes malignancy are long term sequelae of this disorder.

Compound Heterozygous Mutations in the C6 Gene of a Child with Recurrent Infections

Molecular Immunology. Apr, 2014  |  Pubmed ID: 24378253

The complement system plays an important role in both the innate and adaptive immune system. Patients with inherited complement deficiencies have an increased risk of systemic bacterial infections. Deficiencies of the terminal complement pathway are especially associated with invasive meningococcal disease. Here, we report a case of a boy that presented with arthritis and recurrent bacterial and viral infections. Extensive analyses revealed decreased complement activity of both classical and alternative pathway, indicating a deficiency of C3 or one of the factors of the terminal complement pathway. Mutational analysis of the C6 gene identified two compound heterozygous mutations. An unknown missense aberration was found that involves the loss of a cysteine, possibly affecting the 3D structure of the protein. Furthermore, a known splice site variation was identified that results in a 14% shorter protein, due to transcription of amino acids that are normally intronic until a stop codon is reached (exon-intron boundary defect). It is known that the protein with this latter aberration is still functionally active when present with other C6 mutations and therefore, the consequences of the combination of the identified variations have been studied. Quantitative ELISAs showed that at least one allele produced a circulating C6 molecule that can be incorporated in the membrane attack complex, likely the truncated protein. In the present case we observed relapsing bacterial and viral infections, but no meningococcal disease. The reduced complement activity can be explained by the identified genetic variations in C6, as recombinant C6 supplementation corrected complement function in vitro.

Primary Immunodeficiency Caused by an Exonized Retroposed Gene Copy Inserted in the CYBB Gene

Human Mutation. Apr, 2014  |  Pubmed ID: 24478191

Retrotransposon-mediated insertion of a long interspersed nuclear element (LINE)-1 or an Alu element into a human gene is a well-known pathogenic mechanism. We report a novel LINE-1-mediated insertion of a transcript from the TMF1 gene on chromosome 3 into the CYBB gene on the X-chromosome. In a Dutch male patient with chronic granulomatous disease, a 5.8-kb, incomplete and partly exonized TMF1 transcript was identified in intron 1 of CYBB, in opposite orientation to the host gene. The sequence of the insertion showed the hallmarks of a retrotransposition event, with an antisense poly(A) tail, target site duplication, and a consensus LINE-1 endonuclease cleavage site. This insertion induced aberrant CYBB mRNA splicing, with inclusion of an extra 117-bp exon between exons 1 and 2 of CYBB. This extra exon contained a premature stop codon. The retrotransposition took place in an early stage of fetal development in the mother of the patient, because she showed a somatic mosaicism for the mutation that was not present in the DNA of her parents. However, the mutated allele was not expressed in the patient's mother because the insertion was found only in the methylated fraction of her DNA.

Screening of the Central Nervous System in Children with Invasive Pulmonary Aspergillosis

Medical Mycology Case Reports. Apr, 2014  |  Pubmed ID: 24624324

The existing guidelines regarding the management of invasive pulmonary aspergillosis do not recommend screening of the extra-pulmonary sites. Due to the fact that the presence of central nervous system (CNS) aspergillosis will influence treatment decisions regarding which antifungal to use and the aimed target concentrations of azoles in plasma, to be informed about dissemination of the infection to the CNS is absolutely necessary. We demonstrate the need for a structured approach to screening of pediatric patients for CNS aspergillosis.

Fourth European Conference on Infections in Leukaemia (ECIL-4): Guidelines for Diagnosis, Prevention, and Treatment of Invasive Fungal Diseases in Paediatric Patients with Cancer or Allogeneic Haemopoietic Stem-cell Transplantation

The Lancet. Oncology. Jul, 2014  |  Pubmed ID: 24988936

Invasive opportunistic fungal diseases (IFDs) are important causes of morbidity and mortality in paediatric patients with cancer and those who have had an allogeneic haemopoietic stem-cell transplantation (HSCT). Apart from differences in underlying disorders and comorbidities relative to those of adults, IFDs in infants, children, and adolescents are unique with respect to their epidemiology, the usefulness of diagnostic methods, the pharmacology and dosing of antifungal agents, and the absence of interventional phase 3 clinical trials for guidance of evidence-based decisions. To better define the state of knowledge on IFDs in paediatric patients with cancer and allogeneic HSCT and to improve IFD diagnosis, prevention, and management, the Fourth European Conference on Infections in Leukaemia (ECIL-4) in 2011 convened a group that reviewed the scientific literature on IFDs and graded the available quality of evidence according to the Infectious Diseases Society of America grading system. The final considerations and recommendations of the group are summarised in this manuscript.

The Biology of Pulmonary Aspergillus Infections

The Journal of Infection. Nov, 2014  |  Pubmed ID: 25135079

Pulmonary aspergillus infections are mainly caused by Aspergillus fumigatus and can be classified based on clinical syndromes into saphrophytic infections, allergic disease and invasive disease. Invasive pulmonary aspergillosis, occurring in immunocompromised patients, reflects the most serious disease with a high case-fatality rate. Patients with cystic fibrosis and severe asthma might develop allergic bronchopulmonary aspergillosis, while saphrophytic infections are observed in patients with lung cavities mainly due to tuberculosis. Histopathologically, a differentiation can be made into angio-invasive and airway-invasive disease. If the host response is too weak or too strong, Aspergillus species are able to cause disease characterized either by damage from the fungus itself or through an exaggerated inflammatory response of the host, in both situations leading to overt disease associated with specific clinical signs and symptoms. The unraveling of the specific host - Aspergillus interaction has not been performed to a great extent and needs attention to improve the management of those clinical syndromes.

Country of Birth Does Not Influence Long-term Clinical, Virologic, and Immunological Outcome of HIV-infected Children Living in the Netherlands: a Cohort Study Comparing Children Born in the Netherlands with Children Born in Sub-Saharan Africa

Journal of Acquired Immune Deficiency Syndromes (1999). Feb, 2015  |  Pubmed ID: 25405830

Immigrant HIV-infected adults in industrialized countries show a poorer clinical and virologic outcome compared with native patients. We aimed to investigate potential differences in clinical, immunological, and virologic outcome in Dutch HIV-infected children born in the Netherlands (NL) versus born in Sub-Saharan Africa (SSA) in a national cohort analysis.

Direct Multiplexed Whole Genome Sequencing of Respiratory Tract Samples Reveals Full Viral Genomic Information

Journal of Clinical Virology : the Official Publication of the Pan American Society for Clinical Virology. May, 2015  |  Pubmed ID: 25866327

Acute respiratory tract infections (RTI) cause substantial morbidity during childhood, and are responsible for the majority of pediatric infectious diseases. Although most acute RTI are thought to be of viral origin, viral etiology is still unknown in a significant number of cases.

Azole-resistant Aspergillosis

The Journal of Infection. Jun, 2015  |  Pubmed ID: 25917808

Azole-resistance in Aspergillus fumigatus is emerging and is becoming an increasing problem in the management of aspergillosis. Two types of development of resistance have been described; resistance acquired during azole treatment in an individual patient and through environmental exposure to fungicides. The main molecular mechanism of azole resistance in A. fumigatus is explained by mutations in the cyp51A-gene. The environmental route of resistance development is particularly worrying and may affect all patients whether azole exposed or naïve, and whether suffering from acute or chronic aspergillosis. No management guidelines to assist clinicians confronted with azole-resistant aspergillosis are available and pre-clinical and clinical evidence supporting treatment choices is scarce.

Impact of Special Patient Populations on the Pharmacokinetics of Echinocandins

Expert Review of Anti-infective Therapy. Jun, 2015  |  Pubmed ID: 25947367

Echinocandins belong to the class of antifungal agents. Currently, three echinocandin drugs are licensed for intravenous treatment of invasive fungal infections: anidulafungin, caspofungin and micafungin. While their antifungal activity overlaps, there are substantial differences in pharmacokinetics (PK). Numerous factors may account for variability in PK of echinocandins including age (pediatrics vs adults), body surface area and body composition (normal weight vs obesity), disease status (e.g., critically ill and burn patients) and organ dysfunction (kidney and liver impairment). Subsequent effects of altered exposure might impact efficacy and safety. Knowledge of PK behavior is crucial in optimal clinical utilization of echinocandin in a specific patient or patient population. This review provides up-to-date information on PK data of anidulafungin, caspofungin and micafungin in special patient populations. Patient populations addressed are neonates, children and adolescents, obese patients, patients with hepatic or renal impairment, critically ill patients (including burn patients) and patients with hematological diseases.

International Expert Opinion on the Management of Infection Caused by Azole-resistant Aspergillus Fumigatus

Drug Resistance Updates : Reviews and Commentaries in Antimicrobial and Anticancer Chemotherapy. Jul-Aug, 2015  |  Pubmed ID: 26282594

An international expert panel was convened to deliberate the management of azole-resistant aspergillosis. In culture-positive cases, in vitro susceptibility testing should always be performed if antifungal therapy is intended. Different patterns of resistance are seen, with multi-azole and pan-azole resistance more common than resistance to a single triazole. In confirmed invasive pulmonary aspergillosis due to an azole-resistant Aspergillus, the experts recommended a switch from voriconazole to liposomal amphotericin B (L-AmB; Ambisome(®)). In regions with environmental resistance rates of ≥10%, a voriconazole-echinocandin combination or L-AmB were favoured as initial therapy. All experts recommended L-AmB as core therapy for central nervous system aspergillosis suspected to be due to an azole-resistant Aspergillus, and considered the addition of a second agent with the majority favouring flucytosine. Intravenous therapy with either micafungin or L-AmB given as either intermittent or continuous therapy was recommended for chronic pulmonary aspergillosis due to a pan-azole-resistant Aspergillus. Local and national surveillance with identification of clinical and environmental resistance patterns, rapid diagnostics, better quality clinical outcome data, and a greater understanding of the factors driving or minimising environmental resistance are areas where research is urgently needed, as well as the development of new oral agents outside the azole drug class.

Ataxia Telangiectasia: Why Should the ERS Care?

The European Respiratory Journal. Dec, 2015  |  Pubmed ID: 26621885

ERS Statement on the Multidisciplinary Respiratory Management of Ataxia Telangiectasia

European Respiratory Review : an Official Journal of the European Respiratory Society. Dec, 2015  |  Pubmed ID: 26621971

Ataxia telangiectasia (A-T) is a rare, progressive, multisystem disease that has a large number of complex and diverse manifestations which vary with age. Patients with A-T die prematurely with the leading causes of death being respiratory diseases and cancer. Respiratory manifestations include immune dysfunction leading to recurrent upper and lower respiratory infections; aspiration resulting from dysfunctional swallowing due to neurodegenerative deficits; inefficient cough; and interstitial lung disease/pulmonary fibrosis. Malnutrition is a significant comorbidity. The increased radiosensitivity and increased risk of cancer should be borne in mind when requesting radiological investigations. Aggressive proactive monitoring and treatment of these various aspects of lung disease under multidisciplinary expertise in the experience of national multidisciplinary clinics internationally forms the basis of this statement on the management of lung disease in A-T. Neurological management is outwith the scope of this document.

Prophylactic Antibiotics Should Be Used in Children with Repaired Oesophageal Atresia and Tracheo-oesophageal Fistula: The Case Against

Paediatric Respiratory Reviews. Mar, 2016  |  Pubmed ID: 26654949

Bacterial Tracheitis and Septic Shock

The Pediatric Infectious Disease Journal. Feb, 2016  |  Pubmed ID: 26756267

The European Paediatric Mycology Network (EPMyN): Towards a Better Understanding and Management of Fungal Infections in Children

Current Fungal Infection Reports. 2016  |  Pubmed ID: 27127543

The European Paediatric Mycology Network (EPMyN) was launched in 2014 to create a European platform for research and education in the field of paediatric mycology. The EPMyN aims to address the lack of paediatric specific evidence and knowledge needed to (1) improve the management and outcome of invasive fungal infections in children and neonates and to (2) enhance and develop paediatric antifungal stewardship programmes.

Decreased Cell Wall Galactosaminogalactan in Aspergillus Nidulans Mediates Dysregulated Inflammation in the Chronic Granulomatous Disease Host

Journal of Interferon & Cytokine Research : the Official Journal of the International Society for Interferon and Cytokine Research. Aug, 2016  |  Pubmed ID: 27142572

Invasive aspergillosis is a major threat to patients suffering from impaired neutrophil function, with Aspergillus fumigatus being the most common species causing this life-threatening condition. Patients with chronic granulomatous disease (CGD) not only develop infections with A. fumigatus, but also exhibit a unique susceptibility to infection with the normally nonpathogenic species Aspergillus nidulans. In this study, we compared the inflammatory cytokine response of peripheral blood mononuclear cells (PBMCs) from healthy and CGD patients to these two fungal species. CGD patients displayed evidence for a chronic hyperinflammatory state as indicated by elevated plasma IL-1β and TNF-α levels. PBMCs isolated from CGD patients secreted higher levels of IL-1β and TNF-α in response to A. nidulans as compared with A. fumigatus. The presence or absence of melanin in the cell wall of A. nidulans did not alter the cytokine release by healthy or CGD PBMCs. In contrast, A. fumigatus mutants lacking melanin stimulated higher levels of proinflammatory cytokine release from healthy, but not CGD PBMCs. Purified cell wall polysaccharides of A. nidulans induced a much higher level of IL-1β secretion by CGD PBMCs than did cell wall polysaccharides isolated from A. fumigatus. Using modified A. nidulans strains overexpressing galactosaminogalactan, we were able to show that the increased secretion of inflammatory cytokines by CGD PBMCs in response to A. nidulans are a consequence of low levels of cell wall-associated galactosaminogalactan in this species.

A New Paediatric Formulation of Valaciclovir: Development and Bioequivalence Assessment

Archives of Disease in Childhood. Oct, 2016  |  Pubmed ID: 27162003

Aspergillus Infections in Cystic Fibrosis

The Journal of Infection. Jul, 2016  |  Pubmed ID: 27177733

Patients with cystic fibrosis (CF) suffer from chronic lung infection and airway inflammation. Respiratory failure secondary to chronic or recurrent infection remains the commonest cause of death and accounts for over 90% of mortality. Bacteria as Staphylococcus aureus, Pseudomonas aeruginosa and Burkholderia cepacia complex have been regarded the main CF pathogens and their role in progressive lung decline has been studied extensively. Little attention has been paid to the role of Aspergillus spp. and other filamentous fungi in the pathogenesis of non-ABPA (allergic bronchopulmonary aspergillosis) respiratory disease in CF, despite their frequent recovery in respiratory samples. It has become more apparent however, that Aspergillus spp. may play an important role in chronic lung disease in CF. Research delineating the underlying mechanisms of Aspergillus persistence and infection in the CF lung and its link to lung deterioration is lacking. This review summarizes the Aspergillus disease phenotypes observed in CF, discusses the role of CFTR (cystic fibrosis transmembrane conductance regulator)-protein in innate immune responses and new treatment modalities.

Sputum Induction in Children Is Feasible and Useful in a Bustling General Hospital Practice

Global Pediatric Health. 2016  |  Pubmed ID: 27336008

We prospectively studied the feasibility and effectiveness of sputum induction in obtaining good quality sputum and its subsequent bacterial yield in children with clinically suspected acute lower-respiratory-tract infection (aLRTI). Good quality sputum was collected in 89/98 (91%) patients. Sputum cultures revealed ≥1 bacterial pathogens in 22 cases (25%). Adverse events were infrequent and mild (6%). Sputum induction is feasible in young children and leads to an increased number of etiological diagnoses of aLRTI.


The Journal of Infection. Jul, 2016  |  Pubmed ID: 27339109

The Role of the Multidisciplinary Team in Antifungal Stewardship

The Journal of Antimicrobial Chemotherapy. Nov, 2016  |  Pubmed ID: 27880668

There are a variety of challenges faced in the management of invasive fungal diseases (IFD), including high case-fatality rates, high cost of antifungal drugs and development of antifungal resistance. The diagnostic challenges and poor outcomes associated with IFD have resulted in excessive empirical use of antifungals in various hospital settings, exposing many patients without IFD to potential drug toxicities as well as causing spiralling antifungal drug costs. Further complexity arises as different patient groups show marked variation in their risk for IFD, fungal epidemiology, sensitivity and specificity of diagnostic tests and the pharmacokinetics and pharmacodynamics of antifungal drugs. To address these issues and to ensure optimal management of IFD, specialist knowledge and experience from a range of backgrounds is required, which extends beyond the remit of most antibiotic stewardship programmes. The first step in the development of any antifungal stewardship (AFS) programme is to build a multidisciplinary team encompassing the necessary expertise in the management of IFD to develop and implement the AFS programme. The specific roles of the key individuals within the AFS team and the importance of collaboration are discussed in this article.

Neutropenic Acute Acalculous Cholecystitis (AAC) in a 12-year-old Boy with T-acute Lymphoblastic Leukemia Successfully Managed with Conservative Treatment

Pediatric Hematology and Oncology. Jan, 2017  |  Pubmed ID: 28085529

Acute acalculous cholecystitis (AAC) is an inflammation of the gallbladder without the presence of gallstones. In children with malignancies or chemotherapy-induced neutropenia, AAC is very rare. Clinical diagnosis of AAC remains difficult in this patient population but an early recognition followed by an appropriate intervention may confer a benefit. Only three pediatric patients with underlying hematological malignancies whose clinical treatment course was complicated by the development of AAC have been described. We describe a neutropenic pediatric patient who developed AAC following chemotherapy for acute T-cell acute lymphoblastic leukemia (T-ALL), which was successfully managed with conservative treatment.

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