JoVE Visualize What is visualize?
Stop Reading. Start Watching.
Advanced Search
Stop Reading. Start Watching.
Regular Search
Find video protocols related to scientific articles indexed in Pubmed.
Country of birth does not influence long-term clinical, virological and immunological outcome of HIV-infected children living in the Netherlands: a cohort study comparing children born in the Netherlands to children born in sub-Saharan Africa.
J. Acquir. Immune Defic. Syndr.
PUBLISHED: 11-19-2014
Show Abstract
Hide Abstract
Immigrant HIV-infected adults in industrialized countries show a poorer clinical and virological outcome compared to native patients. We aimed to investigate potential differences in clinical, immunological and virological outcome in Dutch HIV-infected children born in the Netherlands (NL) versus born in Sub-Saharan Africa (SSA) in a national cohort-analysis.
Related JoVE Video
Inhibition of Fc?R-mediated phagocytosis by IVIg is independent of IgG-Fc sialylation and Fc?RIIb in human macrophages.
Blood
PUBLISHED: 10-30-2014
Show Abstract
Hide Abstract
In immune thrombocytopenia (ITP) and warm autoimmune hemolytic anemia (wAIHA), circulating IgG-opsonized blood cells are cleared from the circulation by macrophages. Administration of intravenous immunoglobulin (IVIg) can prevent uptake, but the exact working mechanism is not known. The prevailing theory from murine studies, which states that Fc-sialylated IgG alters the balance between activating and inhibitory Fc-gamma receptors (Fc?Rs) by inducing upregulation of the inhibitory Fc?RIIb on effector macrophages, is currently debated. We studied phagocytosis of IgG-opsonized blood cells in a human system, assessing the effect of IVIg and blocking anti-Fc?R F(ab')2 fragments on uptake by monocyte-derived macrophages (both M1 and M2 macrophages). Phagocytosis was remarkably sensitive to administration of IVIg but unexpectedly, recombinant Fc-sialylated IgG or sialic acid-enriched IVIg were equally active as unsialylated IgG fractions in mediating this inhibition - independent of Fc?RIIb expression. Instead, IVIg inhibited phagocytosis by direct blockade of Fc?Rs. IgG fractions enriched for IgG-dimers with enhanced avidity for Fc?Rs showed increased inhibition compared to monomeric IgG fractions. Together, our data demonstrate that inhibition of IgG-mediated phagocytosis in human macrophages by IVIg is dependent on the capacity to directly bind Fc?Rs but independent of Fc?RIIb or sialylation of the Fc fragment in the human setting.
Related JoVE Video
PKC? is dispensible for oxLDL uptake and foam cell formation by human and murine macrophages.
Cardiovasc. Res.
PUBLISHED: 09-24-2014
Show Abstract
Hide Abstract
Uptake of oxidized lipoprotein particles (oxLDL) and foam cell formation by macrophages is one of the first steps in the development of atherosclerosis. Recently, protein kinase C ? (PKC?) has been implicated as a regulator of oxLDL uptake and foam cell formation via down-regulation of PKC? and scavenger receptors CD36 and SR-A expression. Here, we describe studies in which we have re-evaluated the role of PKC? in oxLDL uptake and foam cell formation.
Related JoVE Video
Frequency of joint involvement in juvenile idiopathic arthritis during a 5-year follow-up of newly diagnosed patients: implications for MR imaging as outcome measure.
Rheumatol. Int.
PUBLISHED: 08-14-2014
Show Abstract
Hide Abstract
To assess the sequence and type of active joints in a cohort of newly diagnosed juvenile idiopathic arthritis (JIA) patients with full access to current treatment at first visit and during a follow-up period of 5-years, in order to identify an index joint/group of joints for magnetic resonance imaging in JIA. Patient charts of all consecutive newly diagnosed JIA patients with a follow-up duration of at least 5 years were analyzed. Patients were derived from two tertiary pediatric rheumatology centers. Patient characteristics and data concerning the presence of joints with arthritis and the use of medication were recorded. Findings from 95 JIA patients [39 (41 %) oligoarticular and 56 (59 %) polyarticular] were analyzed. At first visit, distribution of active joints among patients was as follows: knee (n = 70, 74 %), ankle (n = 55, 58 %), elbow (n = 23, 24 %), wrist (n = 23, 24 %), metacarpophalangeal (MCP) (n = 20, 21 %), proximal interphalangeal (PIP) (n = 13, 14 %), hip (n = 6, 6 %), shoulder (n = 5, 5 %), and distal interphalangeal (DIP) (n = 4, 4 %) joints. After a follow-up period of 5 years, the cumulative percentage of patients with specific joint involvement changed into: knee (n = 88, 93 %), ankle (n = 79, 83 %), elbow (n = 43, 45 %), wrist (n = 38, 40 %), MCP (n = 36, 38 %), PIP (n = 29, 31 %), shoulder (n = 20, 21 %), hip (n = 17, 19 %), and DIP (n = 9, 10 %) joints. Despite changes in treatment strategies over the years, the knee remains the most commonly involved joint at onset and during follow-up in JIA, followed by the ankle, elbow, and wrist. For the evaluation of outcome with MRI, the knee appears the most appropriate joint in JIA.
Related JoVE Video
Health related quality of life and parental perceptions of child vulnerability among parents of a child with juvenile idiopathic arthritis: results from a web-based survey.
Pediatr Rheumatol Online J
PUBLISHED: 08-07-2014
Show Abstract
Hide Abstract
A chronic illness, such as Juvenile Idiopathic Arthritis (JIA), has an impact on the whole family, especially on parents caring for the ill child. Therefore the aim of this study is to evaluate parental Health Related Quality of Life (HRQOL) and parental perceptions of child vulnerability (PPCV) and associated variables in parents of a child with JIA.
Related JoVE Video
TFPI inhibits lectin pathway of complement activation by direct interaction with MASP-2.
Eur. J. Immunol.
PUBLISHED: 07-29-2014
Show Abstract
Hide Abstract
The lectin pathway (LP) of complement has a protective function against invading pathogens. Recent studies have also shown that the LP plays an important role in ischemia/reperfusion (I/R)-injury. MBL-associated serine protease (MASP)-2 appears to be crucial in this process. The serpin C1-inhibitor is the major inhibitor of MASP-2. In addition, aprotinin, a Kunitz-type inhibitor, was shown to inhibit MASP-2 activity in vitro. In this study we investigated whether the Kunitz-type inhibitor tissue factor pathway inhibitor (TFPI) is also able to inhibit MASP-2. Ex vivo LP was induced and detected by C4-deposition on mannan-coated plates. The MASP-2 activity was measured in a fluid-phase chromogenic assay. rTFPI in the absence or presence of specific monoclonal antibodies was used to investigate which TFPI-domains contribute to MASP-2 inhibition. Here, we identify TFPI as a novel selective inhibitor of MASP-2, without affecting MASP-1 or the classical pathway proteases C1s and C1r. Kunitz-2 domain of TFPI is required for the inhibition of MASP-2. Considering the role of MASP-2 in complement-mediated I/R-injury, the inhibition of this protease by TFPI could be an interesting therapeutic approach to limit the tissue damage in conditions such as cerebral stroke, myocardial infarction or solid organ transplantation. This article is protected by copyright. All rights reserved.
Related JoVE Video
Fc?RIIa cross-talk with TLRs, IL-1R, and IFN?R selectively modulates cytokine production in human myeloid cells.
Immunobiology
PUBLISHED: 07-25-2014
Show Abstract
Hide Abstract
Myeloid antigen-presenting cells (APCs) tailor immune responses to the pathogen involved through the production of specific pro- and anti-inflammatory cytokines. It is becoming increasingly clear that the ultimate cytokine profile produced by myeloid APCs crucially depends on interaction between multiple pathogen recognizing receptors. In this respect, we recently identified an important role for cross-talk between Fc gamma receptor IIa (Fc?RIIa) and Toll-like receptors (TLRs) in human dendritic cells (DCs), which induces anti-bacterial immunity through the selective induction of TNF? and Th17-promoting cytokines. Here, we show that Fc?RIIa-TLR cross-talk is not restricted to DCs, but is a common feature of various human myeloid APC subsets including monocytes and macrophages. Interestingly, Fc?RIIa-TLR cross-talk in monocytes resulted in the induction of a cytokine profile distinct from that in DCs and macrophages, indicating that Fc?RIIa stimulation induces cell-type and tissue specific responses. Surprisingly, we show that the FCGR2A H131R single nucleotide polymorphism (SNP), which is known to greatly affect Fc?RIIa-mediated uptake of IgG2-opsonized bacteria, did not affect Fc?RIIa-dependent cytokine production, indicating that these processes are differently regulated. In addition, we demonstrate that Fc?RIIa selectively synergized with TLRs, IL-1R, and IFN?R, but did not affect cytokine production induced by other receptors such as C-type lectin receptor Dectin-1. Taken together, these data demonstrate that Fc?RIIa-dependent modulation of cytokine production is more widespread than previously considered, and indicate that cross-talk of Fc?RIIa with various receptors and in multiple cell types contributes to the induction of pathogen and tissue-specific immunity.
Related JoVE Video
Human CalDAG-GEFI gene (RASGRP2) mutation affects platelet function and causes severe bleeding.
J. Exp. Med.
PUBLISHED: 06-23-2014
Show Abstract
Hide Abstract
The nature of an inherited platelet disorder was investigated in three siblings affected by severe bleeding. Using whole-exome sequencing, we identified the culprit mutation (cG742T) in the RAS guanyl-releasing protein-2 (RASGRP2) gene coding for calcium- and DAG-regulated guanine exchange factor-1 (CalDAG-GEFI). Platelets from individuals carrying the mutation present a reduced ability to activate Rap1 and to perform proper ?IIb?3 integrin inside-out signaling. Expression of CalDAG-GEFI mutant in HEK293T cells abolished Rap1 activation upon stimulation. Nevertheless, the PKC- and ADP-dependent pathways allow residual platelet activation in the absence of functional CalDAG-GEFI. The mutation impairs the platelet's ability to form thrombi under flow and spread normally as a consequence of reduced Rac1 GTP-binding. Functional deficiencies were confined to platelets and megakaryocytes with no leukocyte alteration. This contrasts with the phenotype seen in type III leukocyte adhesion deficiency caused by the absence of kindlin-3. Heterozygous did not suffer from bleeding and have normal platelet aggregation; however, their platelets mimicked homozygous ones by failing to undergo normal adhesion under flow and spreading. Rescue experiments on cultured patient megakaryocytes corrected the functional deficiency after transfection with wild-type RASGRP2. Remarkably, the presence of a single normal allele is sufficient to prevent bleeding, making CalDAG-GEFI a novel and potentially safe therapeutic target to prevent thrombosis.
Related JoVE Video
Two independent killing mechanisms of Candida albicans by human neutrophils: evidence from innate immunity defects.
Blood
PUBLISHED: 06-19-2014
Show Abstract
Hide Abstract
Invasive fungal infections, accompanied by high rates of mortality, represent an increasing problem in medicine. Neutrophils are the major effector immune cells in fungal killing. Based on studies with neutrophils from patients with defined genetic defects, we provide evidence that human neutrophils use 2 distinct and independent phagolysosomal mechanisms to kill Candida albicans. The first mechanism for the killing of unopsonized C albicans was found to be dependent on complement receptor 3 (CR3) and the signaling proteins phosphatidylinositol-3-kinase and caspase recruitment domain-containing protein 9 (CARD9), but was independent of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity. The second mechanism for the killing of opsonized C albicans was strictly dependent on Fc? receptors, protein kinase C (PKC), and reactive oxygen species production by the NADPH oxidase system. Each of the 2 pathways of Candida killing required Syk tyrosine kinase activity, but dectin-1 was dispensable for both of them. These data provide an explanation for the variable clinical presentation of fungal infection in patients suffering from different immune defects, including dectin-1 deficiency, CARD9 deficiency, or chronic granulomatous disease.
Related JoVE Video
Fetal exposure to HIV-1 alters chemokine receptor expression by CD4+T cells and increases susceptibility to HIV-1.
Sci Rep
PUBLISHED: 06-16-2014
Show Abstract
Hide Abstract
Absolute numbers of lymphocytes are decreased in uninfected infants born to HIV-1-infected women (HIV-1-exposed). Although the exact mechanism is unknown, fetal exposure to maternal HIV-1-infection could prime the immune system and affect T cell trafficking. We compared the expression of chemokine receptors on cord blood CD4(+) T cells from HIV-1-exposed children and healthy controls. At baseline CD4(+) T cells had a largely naïve phenotype. However, stimulation with cytokines resulted in an upregulation of inflammatory response-related chemokine receptors on CD4(+) T cells, with HIV-1-exposed infants having a significantly higher frequency of CD4(+) T cells expressing, in particularly Th2 associated chemokine receptors (CCR3 p < 0.01, CCR8 p = 0.03). Numbers of naive CCR7(+) CD4(+) T cells were reduced (p = 0.01) in HIV-1-exposed infants. We further assessed whether the inflammatory phenotype was associated with susceptibility to HIV-1 and detected higher levels of p24 upon in in vitro infection of stimulated CD4(+) T cells of HIV-1-exposed infants. In summary, fetal exposure to HIV-1 primes the immune system in the infant leading to an enhanced immune activation and altered T cell homing, with potential ramifications regarding T cell responses and the acquisition of HIV-1 as an infant.
Related JoVE Video
Aicardi-Goutières syndrome harbours abundant systemic and brain-reactive autoantibodies.
Ann. Rheum. Dis.
PUBLISHED: 06-08-2014
Show Abstract
Hide Abstract
Aicardi-Goutières syndrome (AGS) is an autoimmune disorder that shares similarities with systemic lupus erythematous. AGS inflammatory responses specially target the cerebral white matter. However, it remains uncertain why the brain is the most affected organ, and little is known about the presence of autoantibodies in AGS. Here, we aim to profile specific autoantibodies in AGS and to determine whether these autoantibodies target cerebral epitopes.
Related JoVE Video
Ribosomal protein mutations induce autophagy through S6 kinase inhibition of the insulin pathway.
PLoS Genet.
PUBLISHED: 05-01-2014
Show Abstract
Hide Abstract
Mutations affecting the ribosome lead to several diseases known as ribosomopathies, with phenotypes that include growth defects, cytopenia, and bone marrow failure. Diamond-Blackfan anemia (DBA), for example, is a pure red cell aplasia linked to the mutation of ribosomal protein (RP) genes. Here we show the knock-down of the DBA-linked RPS19 gene induces the cellular self-digestion process of autophagy, a pathway critical for proper hematopoiesis. We also observe an increase of autophagy in cells derived from DBA patients, in CD34+ erythrocyte progenitor cells with RPS19 knock down, in the red blood cells of zebrafish embryos with RP-deficiency, and in cells from patients with Shwachman-Diamond syndrome (SDS). The loss of RPs in all these models results in a marked increase in S6 kinase phosphorylation that we find is triggered by an increase in reactive oxygen species (ROS). We show that this increase in S6 kinase phosphorylation inhibits the insulin pathway and AKT phosphorylation activity through a mechanism reminiscent of insulin resistance. While stimulating RP-deficient cells with insulin reduces autophagy, antioxidant treatment reduces S6 kinase phosphorylation, autophagy, and stabilization of the p53 tumor suppressor. Our data suggest that RP loss promotes the aberrant activation of both S6 kinase and p53 by increasing intracellular ROS levels. The deregulation of these signaling pathways is likely playing a major role in the pathophysiology of ribosomopathies.
Related JoVE Video
Distribution pattern of MRI abnormalities within the knee and wrist of juvenile idiopathic arthritis patients: signature of disease activity.
AJR Am J Roentgenol
PUBLISHED: 04-25-2014
Show Abstract
Hide Abstract
The aim of this study in clinically active juvenile idiopathic arthritis (JIA) was to assess the frequency and distribution pattern of synovitis as hallmark of disease and additional soft-tissue and bony abnormalities on MRI in the knee and wrist as two target joints.
Related JoVE Video
Haplotypes of Fc?RIIa and Fc?RIIIb polymorphic variants influence IgG-mediated responses in neutrophils.
J. Immunol.
PUBLISHED: 02-19-2014
Show Abstract
Hide Abstract
Human blood neutrophils normally express two Fc?Rs (Fc?RIIa and Fc?RIIIb) that, upon multivalent binding of IgG in immune complexes or on opsonized targets, mediate responses such as phagocytosis, Ab-dependent cellular cytotoxicity, and respiratory burst. Allelic variants have been described for both Fc?RIIa (131H/R) and Fc?RIIIb (NA1/NA2/SH), with different binding affinity for IgG subclasses. Because neither of these variants acts alone, we have set out to systematically analyze in a large cohort of healthy FCGR2/3-genotyped volunteers how the different haplotypes of neutrophil Fc?Rs functionally interact. Maximal IgG-induced H2O2 production by neutrophils from individuals with different (homozygous) haplotypes was observed in the following order: 131HH-NA2NA2 > 131RR-NA1NA1 > 131HH-NA1NA1 > 131RR-NA2NA2. Although Fc?RIIa 131H is known to bind IgG1 and IgG2 more avidly, no such differences in affinity are known for Fc?RIIIb variants. Nonetheless, a remarkable impact of the Fc?RIIIb variants on IgG-mediated neutrophil activity was thus demonstrated, which was not explained by differences in Fc?R surface expression. The Fc?R expression profile was changed by overnight G-CSF/IFN-? activation of the neutrophils and eliminated any haplotypic impact on the respiratory burst. To our knowledge, our results are the first to provide an integrated functional analysis of neutrophil Fc?R haplotypes and suggest that particularly the early phase of IgG-mediated neutrophil reactivity is influenced by FCGR2/3 genotypic variation.
Related JoVE Video
Soluble adhesion molecules as markers for sepsis and the potential pathophysiological discrepancy in neonates, children and adults.
Crit Care
PUBLISHED: 02-18-2014
Show Abstract
Hide Abstract
Sepsis is a severe and life-threatening systemic inflammatory response to infection that affects all populations and age groups. The pathophysiology of sepsis is associated with aberrant interaction between leukocytes and the vascular endothelium. As inflammation progresses, the adhesion molecules that mediate these interactions become shed from cell surfaces and accumulate in the blood as soluble isoforms that are being explored as potential prognostic disease biomarkers. We critically review the studies that have tested the predictive value of soluble adhesion molecules in sepsis pathophysiology with emphasis on age, as well as the underlying mechanisms and potential roles for inflammatory shedding. Five soluble adhesion molecules are associated with sepsis, specifically, E-selectin, L-selectin and P-selectin, intercellular adhesion molecule-1 and vascular cell adhesion molecule-1. While increased levels of these soluble adhesion molecules generally correlate well with the presence of sepsis, their degree of elevation is still poorly predictive of sepsis severity scores, outcome and mortality. Separate analyses of neonates, children and adults demonstrate significant age-dependent discrepancies in both basal and septic levels of circulating soluble adhesion molecules. Additionally, a range of both clinical and experimental studies suggests protective roles for adhesion molecule shedding that raise important questions about whether these should positively or negatively correlate with mortality. In conclusion, while predictive properties of soluble adhesion molecules have been researched intensively, their levels are still poorly predictive of sepsis outcome and mortality. We propose two novel directions for improving clinical utility of soluble adhesion molecules: the combined simultaneous analysis of levels of adhesion molecules and their sheddases; and taking age-related discrepancies into account. Further attention to these issues may provide better understanding of sepsis pathophysiology and increase the usefulness of soluble adhesion molecules as diagnostic and predictive biomarkers.
Related JoVE Video
Five years of Kawasaki disease in the Netherlands: a national surveillance study.
Pediatr. Infect. Dis. J.
PUBLISHED: 01-28-2014
Show Abstract
Hide Abstract
The aim of this study was to evaluate the incidence, disease presentation, treatment and cardiac outcome of Kawasaki disease (KD) in The Netherlands.
Related JoVE Video
Pixel-by-pixel analysis of DCE-MRI curve shape patterns in knees of active and inactive juvenile idiopathic arthritis patients.
Eur Radiol
PUBLISHED: 01-22-2014
Show Abstract
Hide Abstract
To compare DCE-MRI parameters and the relative number of time-intensity curve (TIC) shapes as derived from pixel-by-pixel DCE-MRI TIC shape analysis between knees of clinically active and inactive juvenile idiopathic arthritis (JIA) patients.
Related JoVE Video
Health related quality of life and perceptions of child vulnerability among parents of children with a history of Kawasaki disease.
Acta Paediatr.
PUBLISHED: 01-22-2014
Show Abstract
Hide Abstract
Kawasaki disease (KD) is an acute paediatric vasculitis. The psychosocial consequences of this sudden illness for parents are unknown. This study aimed to evaluate health related quality of life (HRQOL) and parental perceptions of child vulnerability (PPCV) in parents of children with KD, and to identify variables associated with PPCV.
Related JoVE Video
Primary immunodeficiency caused by an exonized retroposed gene copy inserted in the CYBB gene.
Hum. Mutat.
PUBLISHED: 01-10-2014
Show Abstract
Hide Abstract
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.
Related JoVE Video
Variable clinical expressivity of STAT3 mutation in hyperimmunoglobulin E syndrome: genetic and clinical studies of six patients.
J. Clin. Immunol.
PUBLISHED: 01-03-2014
Show Abstract
Hide Abstract
Autosomal dominant Hyper IgE syndrome (AD-HIES) is a rare and complex primary immunodeficiency that affects multiple systems. Mutations in signal transducer and activator of transcription 3 (STAT3) gene cause AD-HIES. These mutations have a dominant-negative effect and the presence of such mutations is associated with a clinical phenotype. We aim to describe genetic and clinical characteristics of patients with AD-HIES in our clinic and to highlight the variability of clinical patterns in the same family.
Related JoVE Video
Failure to detect functional neutrophil B helper cells in the human spleen.
PLoS ONE
PUBLISHED: 01-01-2014
Show Abstract
Hide Abstract
A novel role for human neutrophilic granulocytes was recently described, showing that these cells, upon entering the spleen, can be reprogrammed into a distinct B cell-helper neutrophil phenotype that is capable of eliciting B cell responses such as immunoglobulin secretion, class switch recombination and somatic hypermutation. Using similar protocols, we detected a homogeneous population of CD15(high)CD16(high) neutrophils in fresh human spleen samples, which did not differ in phenotype and function from blood neutrophils. No phenotypic characteristics of costimulatory nature were detected on splenic or circulating neutrophils, nor could we reproduce the immunoglobulin production of splenic B cells in the presence of splenic neutrophils, although B cell function and neutrophil activity were normal. Independent confirmation of a role for NBH cells is required.
Related JoVE Video
One-year Followup Study on Clinical Findings and Changes in Magnetic Resonance Imaging-based Disease Activity Scores in Juvenile Idiopathic Arthritis.
J. Rheumatol.
PUBLISHED: 12-01-2013
Show Abstract
Hide Abstract
To evaluate whether clinical disease activity findings during 1-year followup of patients with juvenile idiopathic arthritis (JIA) is associated with changes of magnetic resonance imaging (MRI)-based disease activity scores.
Related JoVE Video
[Juvenile idiopathic arthritis: from biomarker to treatment].
Ned Tijdschr Geneeskd
PUBLISHED: 11-07-2013
Show Abstract
Hide Abstract
Juvenile idiopathic arthritis (JIA) is the most common cause of chronic joint inflammation in childhood. The aetiology is unknown and the pathogenesis is multifactorial. JIA manifests itself in many various ways. It is a diagnosis of exclusion: other disorders need to be ruled out for a diagnosis to be made. MRI examination is playing an increasingly important role in making a correct early diagnosis and in assessing response to therapy. After 6 months JIA patients are classified, based on clinical characteristics and laboratory results, into one of the JIA categories according to the criteria of the International League of Associations for Rheumatology. Recent developments in therapy, such as starting biological treatment at an early stage, have led to an improvement in the prognosis of JIA and to structural joint damage occurring less often.
Related JoVE Video
Plasma-derived mannose-binding lectin shows a direct interaction with C1-inhibitor.
Mol. Immunol.
PUBLISHED: 10-18-2013
Show Abstract
Hide Abstract
MBL-deficiency has been associated with an increased frequency and severity of infection, in particular in children and under immunocompromized conditions. In an open uncontrolled safety and pharmacokinetic MBL-substitution study using plasma-derived MBL (pdMBL) in MBL-deficient pediatric oncology patients, we found that despite MBL trough levels above 1.0?g/ml MBL functionality was not efficiently restored upon ex vivo testing. PdMBL showed C4-converting activity by itself, indicating the presence of MASPs. Upon incubation of pdMBL with MBL-deficient sera this C4-converting activity was significantly reduced. Depletion of the MASPs from pdMBL, paradoxically, restored the C4-converting activity. Subsequent depletion or inhibition of C1-inh, the major inhibitor of the lectin pathway, in the recipient serum restored the C4-converting activity as well. Complexes between MBL/MASPs and C1-inh (MMC-complexes) were detected after ex vivo substitution of MBL-deficient serum with pdMBL. These MMC-complexes could also be detected in the sera of the patients included in the MBL-substitution study shortly after pdMBL infusion. Altogether, we concluded that active MBL-MASP complexes in pdMBL directly interact with C1-inh in the recipient, leading to the formation of a multimolecular complex between C1-inh and MBL/MASPs, in contrast to the classical pathway where C1r and C1s are dissociated from C1q by C1-inh. Because of the presence of activated MASPs in the current pdMBL products efficient MBL-mediated host protection cannot be expected because of the neutralizing capacity by C1-inh.
Related JoVE Video
Contrast-enhanced MRI compared with the physical examination in the evaluation of disease activity in juvenile idiopathic arthritis.
Eur Radiol
PUBLISHED: 07-29-2013
Show Abstract
Hide Abstract
To assess the value of magnetic resonance imaging (MRI) in discriminating between active and inactive juvenile idiopathic arthritis (JIA) patients and to compare physical examination outcomes with MRI outcomes in the assessment of disease status in JIA patients.
Related JoVE Video
Mg2+ regulates cytotoxic functions of NK and CD8 T cells in chronic EBV infection through NKG2D.
Science
PUBLISHED: 07-13-2013
Show Abstract
Hide Abstract
The magnesium transporter 1 (MAGT1) is a critical regulator of basal intracellular free magnesium (Mg(2+)) concentrations. Individuals with genetic deficiencies in MAGT1 have high levels of Epstein-Barr virus (EBV) and a predisposition to lymphoma. We show that decreased intracellular free Mg(2+) causes defective expression of the natural killer activating receptor NKG2D in natural killer (NK) and CD8(+) T cells and impairs cytolytic responses against EBV. Notably, magnesium supplementation in MAGT1-deficient patients restores intracellular free Mg(2+) and NKG2D while concurrently reducing EBV-infected cells in vivo, demonstrating a link between NKG2D cytolytic activity and EBV antiviral immunity in humans. Moreover, these findings reveal a specific molecular function of free basal intracellular Mg(2+) in eukaryotic cells.
Related JoVE Video
Cutaneous manifestations of primary immunodeficiency.
Curr. Opin. Pediatr.
PUBLISHED: 06-08-2013
Show Abstract
Hide Abstract
To show that skin symptoms help in the recognition of primary immunodeficiencies (PIDs). To analyze whether recent molecular data help in understanding genotype/phenotype relations.
Related JoVE Video
Defects in neutrophil granule mobilization and bactericidal activity in familial hemophagocytic lymphohistiocytosis type 5 (FHL-5) syndrome caused by STXBP2/Munc18-2 mutations.
Blood
PUBLISHED: 05-17-2013
Show Abstract
Hide Abstract
Familial hemophagocytic lymphohistiocytosis (FHL) is caused by genetic defects in cytotoxic granule components or their fusion machinery, leading to impaired natural killer cell and/or T lymphocyte degranulation and/or cytotoxicity. This may accumulate into a life-threatening condition known as macrophage activation syndrome. STXBP2, also known as MUNC18-2, has recently been identified as the disease-causing gene in FHL type 5 (FHL-5). A role for STXBP2 in neutrophils, and for neutrophils in FHL in general, has not been documented thus far. Here, we report that FHL-5 neutrophils have a profound defect in granule mobilization, resulting in inadequate bacterial killing, in particular, of gram-negative Escherichia coli, but not of Staphylococcus aureus, which rather depends on intact reduced NAD phosphate oxidase activity. This impairment of bacterial killing may contribute to the apparent susceptibility to gastrointestinal tract inflammation in patients with FHL-5.
Related JoVE Video
Identification of B cell defects using age-defined reference ranges for in vivo and in vitro B cell differentiation.
J. Immunol.
PUBLISHED: 04-12-2013
Show Abstract
Hide Abstract
Primary immunodeficiencies consist to a large extent of B cell defects, as indicated by inadequate Ab levels or response upon immunization. Many B cell defects have not yet been well characterized. Our objective was to create reliable in vivo and in vitro assays to routinely analyze human B cell differentiation, proliferation, and Ig production and to define reference ranges for different age categories. The in vitro assays were applied to classify the developmental and/or functional B cell defects in patients previously diagnosed with common variable immunodeficiency. Apart from standard immunophenotyping of circulating human B cell subsets, an in vitro CFSE dilution assay was used for the assessment of proliferative capacity comparing T cell-dependent and T cell-independent B cell activation. Plasmablast/plasma cell differentiation was assessed by staining for CD20, CD38, and CD138, and measurement of in vitro Ig secretion. At young age, B cells proliferate upon in vitro activation, but neither differentiate nor produce IgG. These latter functions reached adult levels at 5 and 10 y of age for T cell-dependent versus T cell-independent stimulations, respectively. The capacity of B cells to differentiate into plasmablasts and to produce IgG appeared to be contained within the switched memory B cell pool. Using these assays, we could categorize common variable immunodeficiency patients into subgroups and identified a class-switch recombination defect caused by an UNG mutation in one of the patients. We defined age-related reference ranges for human B cell differentiation. Our findings indicate that in vivo B cell functionality can be tested in vitro and helps to diagnose suspected B cell defects.
Related JoVE Video
A new scoring system derived from base excess and platelet count at presentation predicts mortality in paediatric meningococcal sepsis.
Crit Care
PUBLISHED: 04-03-2013
Show Abstract
Hide Abstract
INTRODUCTION: The aim of this study was to derive a novel prognostic score for mortality in paediatric meningococcal sepsis (MS) based on readily available laboratory markers. METHODS: A multicentre retrospective cohort study for the consortium set and a single centre retrospective study for replication set. The consortium set were 1,073 children (age 1 week to 17.9 years) referred over a 15-year period (1996 to 2011), who had an admission diagnosis of MS, referred to paediatric intensive care units (PICUs) in six different European centres. The consortium set was split into a development set and validation set to derive the score. The replication set were 134 children with MS (age 2 weeks to 16 years) referred over a 4-year period (2007 to 2011) to PICUs via the Childrens Acute Transport Service (CATS), London. RESULTS: A total of 85/1,073 (7.9%) children in the consortium set died. A total of 16/134 (11.9%) children in the replication set died. Children dying in the consortium set had significantly lower base excess, C-reactive protein (CRP), platelet and white cell count, more deranged coagulation and higher lactate than survivors. Paediatric risk of mortality (PRISM) score, Glasgow meningococcal septicaemia prognosis score (GMSPS) and Rotterdam score were also higher. Using the consortium set, a new scoring system using base excess and platelet count at presentation, termed the BEP score, was mathematically developed and validated. BEP predicted mortality with high sensitivity and specificity scores (area under the curve (AUC) in the validation set = 0.86 and in the replication set = 0.96). In the validation set, BEP score performance (AUC = 0.86, confidence interval (CI): 0.80 to 0.91) was better than GMSPS (AUC = 0.77, CI: 0.68, 0.85), similar to Rotterdam (AUC = 0.87, CI: 0.81 to 0.93) and not as good as PRISM (AUC = 0.93, CI: 0.85 to 0.97). CONCLUSIONS: The BEP score, relying on only two variables that are quickly and objectively measurable and readily available at presentation, is highly sensitive and specific in predicting death from MS in childhood.
Related JoVE Video
Elevation of proinflammatory cytokines in patients with Aicardi-Goutières syndrome.
Neurology
PUBLISHED: 02-13-2013
Show Abstract
Hide Abstract
This study explores a large panel of cytokines in plasma and CSF of patients with Aicardi-Goutières syndrome (AGS) at different ages, in order to establish signatures of cytokines most predictive of AGS.
Related JoVE Video
A reversion of an IL2RG mutation in combined immunodeficiency providing competitive advantage to the majority of CD8+ T cells.
Haematologica
PUBLISHED: 02-12-2013
Show Abstract
Hide Abstract
Mutations in the common gamma chain (?c, CD132, encoded by the IL2RG gene) can lead to B(+)T(-)NK(-) X-linked severe combined immunodeficiency, as a consequence of unresponsiveness to ?c-cytokines such as interleukins-2, -7 and -15. Hypomorphic mutations in CD132 may cause combined immunodeficiencies with a variety of clinical presentations. We analyzed peripheral blood mononuclear cells of a 6-year-old boy with normal lymphocyte counts, who suffered from recurrent pneumonia and disseminated mollusca contagiosa. Since proliferative responses of T cells and NK cells to ?c -cytokines were severely impaired, we performed IL2RG gene analysis, showing a heterozygous mutation in the presence of a single X-chromosome. Interestingly, an IL2RG reversion to normal predominated in both naïve and antigen-primed CD8(+) T cells and increased over time. Only the revertant CD8(+) T cells showed normal expression of CD132 and the various CD8(+) T cell populations had a different T-cell receptor repertoire. Finally, a fraction of ??(+) T cells and differentiated CD4(+)CD27(-) effector-memory T cells carried the reversion, whereas NK or B cells were repeatedly negative. In conclusion, in a patient with a novel IL2RG mutation, gene-reverted CD8(+) T cells accumulated over time. Our data indicate that selective outgrowth of particular T-cell subsets may occur following reversion at the level of committed T progenitor cells.
Related JoVE Video
A novel splice variant of Fc?RIIa: a risk factor for anaphylaxis in patients with hypogammaglobulinemia.
J. Allergy Clin. Immunol.
PUBLISHED: 02-11-2013
Show Abstract
Hide Abstract
Our index case was a patient with common variable immunodeficiency (CVID). She had anaphylactoid reactions on administration of intravenous immunoglobulin (IVIg) associated with the presence of IgG antibodies against IgA.
Related JoVE Video
The diagnostic accuracy of unenhanced MRI in the assessment of joint abnormalities in juvenile idiopathic arthritis.
Eur Radiol
PUBLISHED: 02-01-2013
Show Abstract
Hide Abstract
To assess the diagnostic accuracy and reliability of MRI without contrast enhancement in the evaluation of JIA knee joint abnormalities.
Related JoVE Video
Chronic exposure of astrocytes to interferon-? reveals molecular changes related to Aicardi-Goutieres syndrome.
Brain
PUBLISHED: 02-01-2013
Show Abstract
Hide Abstract
Aicardi-Goutières syndrome is a genetically determined infantile encephalopathy, manifesting as progressive microcephaly, psychomotor retardation, and in ?25% of patients, death in early childhood. Aicardi-Goutières syndrome is caused by mutations in any of the genes encoding TREX1, RNASEH2-A, -B, -C and SAMHD1, with protein dysfunction hypothesized to result in the accumulation of nucleic acids within the cell, thus triggering an autoinflammatory response with increased interferon-? production. Astrocytes have been identified as a major source of interferon-? production in the brains of patients with Aicardi-Goutières syndrome. Here, we study the effect of interferon-? treatment on astrocytes derived from immortalized human neural stem cells. Chronic interferon-? treatment promoted astrocyte activation and a reduction in cell proliferation. Moreover, chronic exposure resulted in an alteration of genes and proteins involved in the stability of white matter (ATF4, eIF2B?, cathepsin D, cystatin F), an increase of antigen-presenting genes (human leukocyte antigen class I) and downregulation of pro-angiogenic factors and other cytokines (vascular endothelial growth factor and IL-1). Interestingly, withdrawal of interferon-? for 7 days barely reversed these cellular alterations, demonstrating that the interferon-? mediated effects persist over time. We confirmed our in vitro findings using brain samples from patients with Aicardi-Goutières syndrome. Our results support the idea of interferon-? as a key factor in the pathogenesis of Aicardi-Goutières syndrome relating to the observed leukodystrophy and microangiopathy. Because of the sustained interferon-? effect, even after withdrawal, therapeutic targets for Aicardi-Goutières syndrome, and other interferon-?-mediated encephalopathies, may include downstream interferon-? signalling cascade effectors rather than interferon-? alone.
Related JoVE Video
Aberrant humoral immune reactivity in DOCK8 deficiency with follicular hyperplasia and nodal plasmacytosis.
Clin. Immunol.
PUBLISHED: 01-29-2013
Show Abstract
Hide Abstract
Mutations in the DOCK8 gene define the most common form of autosomal-recessive Hyper-IgE-syndrome (AR-HIES/OMIM#243700). In a patient with extensive molluscum contagiosum lesions, a homozygous DOCK8 gene deletion was demonstrated. In-vivo 18-FDG uptake showed multiple non-enlarged lymph nodes without uptake in the spleen. Lymph node biopsies for subsequent immunohistochemistry showed clear differences with the mouse model of DOCK8 deficiency in which these mice show no GCs. Unexpectedly, the patients lymph nodes demonstrated lymphocyte polyclonality, follicular hyperplasia and an unusual IgE(+) plasma cell expansion. In contrast, the proliferative capacity of circulating B-cells was almost absent with little in-vitro Ig production or plasmablast formation. Also the T-cell proliferation indicated a partial defect. Hematopoietic stem cell transplantation (HSCT) was performed resulting in the disappearance of the molluscum contagiosum lesions. In sum, DOCK8 deficiency results in defective antibody responses and undirected plasma cell expansion in the lymph nodes, as part of a combined immunodeficiency cured by HSCT.
Related JoVE Video
Invasive fungal infection and impaired neutrophil killing in human CARD9 deficiency.
Blood
PUBLISHED: 01-18-2013
Show Abstract
Hide Abstract
Caspase recruitment domain-containing protein 9 (CARD9) is an adaptor molecule in the cytosol of myeloid cells, required for induction of T-helper cells producing interleukin-17 (Th17 cells) and important in antifungal immunity. In a patient suffering from Candida dubliniensis meningoencephalitis, mutations in the CARD9 gene were found to result in the loss of protein expression. Apart from the reduced numbers of CD4(+) Th17 lymphocytes, we identified a lack of monocyte-derived cytokines in response to Candida strains. Importantly, CARD9-deficient neutrophils showed a selective Candida albicans killing defect with abnormal ultrastructural phagolysosomes and outgrowth of hyphae. The neutrophil killing defect was independent of the generation of reactive oxygen species by the reduced NAD phosphate oxidase system. Taken together, this demonstrates that human CARD9 deficiency results in selective defect in the host defense against invasive fungal infection, caused by an impaired phagocyte killing.
Related JoVE Video
A novel flow cytometry-based platelet aggregation assay.
Blood
PUBLISHED: 01-09-2013
Show Abstract
Hide Abstract
The main function of platelets is to maintain normal hemostasis. Inefficient platelet production and/or defective platelet function results in bleeding disorders resulting from a wide range of genetic traits and acquired pathologies. Several platelet function tests have been developed for use in the clinic and in experimental animal models. In particular, platelet aggregation is routinely measured in an aggregometer, which requires normal platelet counts and significant blood sample volumes. For this reason, the analysis of thrombocytopenic patients, infants, and animal models is problematic. We have developed a novel flow cytometry test of platelet aggregation, in which 10- to 25-fold lower platelet counts or sample volumes can be used, either of platelet-rich plasma or whole blood from human subjects or mice. This setup can be applied to test in small assay volumes the influence of a variety of stimuli, drugs, and plasma factors, such as antibodies, on platelet aggregation. The presented principle stands as a novel promising tool, which allows analysis of platelet aggregation in thrombocytopenic patients or infants, and facilitates studies in platelets obtained from experimental animal models without the need of special devices but a flow cytometer.
Related JoVE Video
Effectiveness of a web-based application to monitor health-related quality of life.
Pediatrics
PUBLISHED: 01-06-2013
Show Abstract
Hide Abstract
Monitoring health-related quality of life (HRQoL) by using electronic patient-reported outcomes (ePROs) has been only minimally evaluated in pediatrics. Children with juvenile idiopathic arthritis (JIA) are at risk for HRQoL problems. The aim of this study was to investigate the effectiveness of ePROs in clinical pediatric rheumatology care.
Related JoVE Video
Replication and meta-analysis of GWAS identified susceptibility loci in kawasaki disease confirm the importance of B lymphoid tyrosine kinase (BLK) in disease susceptibility.
PLoS ONE
PUBLISHED: 01-01-2013
Show Abstract
Hide Abstract
The BLK and CD40 loci have been associated with Kawasaki disease (KD) in two genome-wide association studies (GWAS) conducted in a Taiwanese population of Han Chinese ancestry (Taiwanese) and in Japanese cohorts. Here we build on these findings with replication studies of the BLK and CD40 loci in populations of Korean and European descent. The BLK region was significantly associated with KD susceptibility in both populations. Within the BLK gene the rs2736340-located linkage disequilibrium (LD ) comprising the promoter and first intron was strongly associated with KD, with the combined results of Asian studies including Taiwanese, Japanese, and Korean populations (2,539 KD patients and 7,021 controls) providing very compelling evidence of association (rs2736340, OR?=?1.498, 1.354-1.657; P?=?4.74×10(-31)). We determined the percentage of B cells present in the peripheral blood mononuclear cell (PBMC) population and the expression of BLK in the peripheral blood leukocytes (leukocytes) of KD patients during the acute and convalescent stages. The percentage of B cells in the PBMC population and the expression of BLK in leukocytes were induced in patients in the acute stage of KD. In B cell lines derived from KD patients, and in purified B cells from KD patients obtained during the acute stage, those with the risk allele of rs2736340 expressed significantly lower levels of BLK. These results suggest that peripheral B cells play a pathogenic role during the acute stage of KD. Decreased BLK expression in peripheral blood B cells may alter B cell function and predispose individuals to KD. These associative data suggest a role for B cells during acute KD. Understanding the functional implications may facilitate the development of B cell-mediated therapy for KD.
Related JoVE Video
Extensive variation in gene copy number at the killer immunoglobulin-like receptor locus in humans.
PLoS ONE
PUBLISHED: 01-01-2013
Show Abstract
Hide Abstract
Killer immunoglobulin-like receptors (KIRs) are involved in the regulation of natural killer cell cytotoxicity. Within the human genome seventeen KIR genes are present, which all contain a large number of allelic variants. The high level of homology among KIR genes has hampered KIR genotyping in larger cohorts, and determination of gene copy number variation (CNV) has been difficult. We have designed a multiplex ligation-dependent probe amplification (MLPA) technique for genotyping and CNV determination in one single assay and validated the results by next-generation sequencing and with a KIR gene-specific short tandem repeat assay. In this way, we demonstrate in a cohort of 120 individuals a high level of CNV for all KIR genes except for the framework genes KIR3DL3 and KIR3DL2. Application of our MLPA assay in segregation analyses of families from the Centre dEtude du Polymorphisme Humaine, previously KIR-genotyped by classical techniques, confirmed an earlier reported duplication and resulted in the identification of a novel duplication event in one of these families. In summary, our KIR MLPA assay allows rapid and accurate KIR genotyping and CNV detection, thus rendering improved transplantation programs and oncology treatment feasible, and enables more detailed studies on the role of KIRs in human (auto)immunity and infectious disease.
Related JoVE Video
Neurologic abnormalities in HIV-1 infected children in the era of combination antiretroviral therapy.
PLoS ONE
PUBLISHED: 01-01-2013
Show Abstract
Hide Abstract
Pediatric HIV-1 infection is associated with neurologic abnormalities. In recent years, the neurological outcome of HIV-1 infected children has substantially improved with combination antiretroviral therapy (cART). However, data regarding the long-term effect of cART and neurologic outcome are limited.
Related JoVE Video
Draft consensus guidelines for diagnosis and treatment of Shwachman-Diamond syndrome.
Ann. N. Y. Acad. Sci.
PUBLISHED: 12-24-2011
Show Abstract
Hide Abstract
Shwachman-Diamond syndrome (SDS) is an autosomal recessive disorder characterized by pancreatic exocrine insufficiency and bone marrow failure, often associated with neurodevelopmental and skeletal abnormalities. Mutations in the SBDS gene have been shown to cause SDS. The purpose of this document is to provide draft guidelines for diagnosis, evaluation of organ and system abnormalities, and treatment of hematologic, pancreatic, dietary, dental, skeletal, and neurodevelopmental complications. New recommendations regarding diagnosis and management are presented, reflecting advances in understanding the genetic basis and clinical manifestations of the disease based on the consensus of experienced clinicians from Canada, Europe, and the United States. Whenever possible, evidence-based conclusions are made, but as with other rare diseases, the data on SDS are often anecdotal. The authors welcome comments from readers.
Related JoVE Video
Phenotypic variation in IgG receptors by nonclassical FCGR2C alleles.
J. Immunol.
PUBLISHED: 12-23-2011
Show Abstract
Hide Abstract
The balance between activating and inhibitory signals from the different Fc?Rs for IgG ensures homeostasis of many inflammatory responses. FCGR2C is the product of an unequal crossover of the FCGR2A and FCGR2B genes encoding the activating Fc?RIIa (CD32a) and inhibitory Fc?RIIb (CD32b), respectively. A single nucleotide polymorphism (SNP) in exon 3 of FCGR2C results in either expression of the activating Fc?RIIc (CD32c) (FCGR2C-open reading frame [ORF]) or its absence because of a stop codon (FCGR2C-Stop). Two additional variations in Fc?RIIb/c expression on leukocytes have now been identified. In case of "nonclassical" FCGR2C-ORF alleles, Fc?RIIc expression was unexpectedly absent, because of novel splice site mutations near exon 7 leading to another stop codon. In some individuals with FCGR2C-Stop alleles Fc?RIIb was detected on NK cells, which normally are devoid of this protein. Individuals with these nonclassical FCGR2C-Stop alleles carried a deletion of FCGR2C-FCGR3B that extends into the promoter region of the adjacent FCGR2B gene and probably deletes a negative regulatory element in the FCGR2B promoter in NK cells. Fc?RIIb expression on NK cells effectively inhibited killing mediated by Fc?RIIIa (CD16a) in Ab-dependent cytotoxicity tests. Our findings demonstrate a more extensive and previously unnoticed variation in Fc?R expression with relevance to immunity and inflammation.
Related JoVE Video
Defects in Glanzmann thrombasthenia and LAD-III (LAD-1/v) syndrome: the role of integrin ?1 and ?3 in platelet adhesion to collagen.
Blood
PUBLISHED: 11-07-2011
Show Abstract
Hide Abstract
Patients with Glanzmann thrombasthenia or Leukocyte Adhesion Deficiency-III syndrome (LAD-III or LAD-1/variant) present with increased bleeding tendency because of the lack or dysfunction of the fibrinogen receptor GPIIb/IIIa (integrin ?IIb?3), respectively. Although the bleeding disorder is more severe in LAD-III patients, classic aggregometry or perfusion of Glanzmann or LAD-III platelets over collagen-coated slides under physiologic shear rate does not discriminate between these 2 conditions. However, in a novel flow cytometry-based aggregation assay, Glanzmann platelets were still capable of forming small aggregates upon collagen stimulation, whereas LAD-III platelets were not. These aggregates required functional GPIa/IIa (integrin ?2?1) instead of integrin ?IIb?3, thus explaining the clinically more severe bleeding manifestations in LAD-III patients, in which all platelet integrins are functionally defective. These findings provide genetic evidence for the differential requirements of platelet integrins in thrombus formation and demonstrate that correct integrin function assessment can be achieved with a combination of diagnostic methods.
Related JoVE Video
CD47-signal regulatory protein-? (SIRP?) interactions form a barrier for antibody-mediated tumor cell destruction.
Proc. Natl. Acad. Sci. U.S.A.
PUBLISHED: 10-31-2011
Show Abstract
Hide Abstract
Monoclonal antibodies are among the most promising therapeutic agents for treating cancer. Therapeutic cancer antibodies bind to tumor cells, turning them into targets for immune-mediated destruction. We show here that this antibody-mediated killing of tumor cells is limited by a mechanism involving the interaction between tumor cell-expressed CD47 and the inhibitory receptor signal regulatory protein-? (SIRP?) on myeloid cells. Mice that lack the SIRP? cytoplasmic tail, and hence its inhibitory signaling, display increased antibody-mediated elimination of melanoma cells in vivo. Moreover, interference with CD47-SIRP? interactions by CD47 knockdown or by antagonistic antibodies against CD47 or SIRP? significantly enhances the in vitro killing of trastuzumab-opsonized Her2/Neu-positive breast cancer cells by phagocytes. Finally, the response to trastuzumab therapy in breast cancer patients appears correlated to cancer cell CD47 expression. These findings demonstrate that CD47-SIRP? interactions participate in a homeostatic mechanism that restricts antibody-mediated killing of tumor cells. This provides a rational basis for targeting CD47-SIRP? interactions, using for instance the antagonistic antibodies against human SIRP? described herein, to potentiate the clinical effects of cancer therapeutic antibodies.
Related JoVE Video
Hematologically important mutations: leukocyte adhesion deficiency (first update).
Blood Cells Mol. Dis.
PUBLISHED: 10-18-2011
Show Abstract
Hide Abstract
Leukocyte adhesion deficiency (LAD) is an immunodeficiency caused by defects in the adhesion of leukocytes (especially neutrophils) to the blood vessel wall. As a result, patients with LAD suffer from severe bacterial infections and impaired wound healing, accompanied by neutrophilia. In LAD-I, mutations are found in ITGB2, the gene that encodes the ? subunit of the ?(2) integrins. This syndrome is characterized directly after birth by delayed separation of the umbilical cord. In the rare LAD-II disease, the fucosylation of selectin ligands is disturbed, caused by mutations in SLC35C1, the gene that encodes a GDP-fucose transporter of the Golgi system. LAD-II patients lack the H and Lewis Le(a) and Le(b) blood group antigens. Finally, in LAD-III (also called LAD-I/variant) the conformational activation of the hematopoietically expressed ? integrins is disturbed, leading to leukocyte and platelet dysfunction. This last syndrome is caused by mutations in FERMT3, encoding the kindlin-3 protein in all blood cells that is involved in the regulation of ? integrin conformation.
Related JoVE Video
The dominance of human coronavirus OC43 and NL63 infections in infants.
J. Clin. Virol.
PUBLISHED: 10-12-2011
Show Abstract
Hide Abstract
It is unknown to what extent the human coronaviruses (HCoVs) OC43, HKU1, 229E and NL63 infect healthy children. Frequencies of infections are only known for hospitalized children.
Related JoVE Video
Cardiac magnetic resonance imaging for noninvasive assessment of cardiovascular disease during the follow-up of patients with Kawasaki disease.
Circ Cardiovasc Imaging
PUBLISHED: 09-15-2011
Show Abstract
Hide Abstract
Kawasaki disease (KD) is the most common cause of acquired coronary artery disease in childhood. In KD, the American Heart Association recommends echocardiography for routine coronary artery surveillance and nuclear perfusion scans and conventional coronary angiography in select patients. Cardiac MRI (CMRI) may be a noninvasive and radiation-free alternative. We applied CMRI during the follow-up of patients with KD and assessed the performance of CMRI compared with echocardiography.
Related JoVE Video
Inflammation and repeated infections in CGD: two sides of a coin.
Cell. Mol. Life Sci.
PUBLISHED: 09-13-2011
Show Abstract
Hide Abstract
Chronic granulomatous disease (CGD) is an uncommon congenital immunodeficiency seen approximately in 1 of 250,000 individuals. It is caused by a profound defect in a burst of oxygen consumption that normally accompanies phagocytosis in all myeloid cells (neutrophils, eosinophils, monocytes, and macrophages). This "respiratory burst" involves the catalytic conversion of molecular oxygen to the oxygen free-radical superoxide, which in turn gives rise to hydrogen peroxide, hypochlorous acid, and hydroxyl radicals. These oxygen derivatives play a critical role in the killing of pathogenic bacteria and fungi. As a result of the failure to activate the respiratory burst in their phagocytes, the majority of CGD patients suffer from severe recurrent infections and rather unexplained prolonged inflammatory reactions that may result in granulomatous lesions. Both may cause severe organ dysfunction depending on the tissues involved. Preventive measures as well as rapid (invasive) diagnostic procedures are required to successfully treat CGD. Hematopoietic stem cell transplantation may be a serious option in some of the patients.
Related JoVE Video
Hospitalisation with infection, asthma and allergy in Kawasaki disease patients and their families: genealogical analysis using linked population data.
PLoS ONE
PUBLISHED: 07-22-2011
Show Abstract
Hide Abstract
Kawasaki disease results from an abnormal immunological response to one or more infectious triggers. We hypothesised that heritable differences in immune responses in Kawasaki disease-affected children and their families would result in different epidemiological patterns of other immune-related conditions. We investigated whether hospitalisation for infection and asthma/allergy were different in Kawasaki disease-affected children and their relatives.
Related JoVE Video
Pleconaril revisited: clinical course of chronic enteroviral meningoencephalitis after treatment correlates with in vitro susceptibility.
Antivir. Ther. (Lond.)
PUBLISHED: 07-10-2011
Show Abstract
Hide Abstract
Human enteroviruses (HEVs) can cause severe infections, especially in patients with a deficient humoral immune response, such as X-linked agammaglobulinemia. In this patient group, chronic enteroviral meningitis (CEMA) is feared because of extensive morbidity and high fatality rate. Treatment options consist of intravenous immunoglobulin (IVIG), with various outcomes. Pleconaril is an antiviral agent with in vitro activity against HEVs that has been used in the treatment of HEV infections.
Related JoVE Video
Educational paper: Defects in number and function of neutrophilic granulocytes causing primary immunodeficiency.
Eur. J. Pediatr.
PUBLISHED: 06-21-2011
Show Abstract
Hide Abstract
The neutrophilic granulocyte (neutrophil) is the most important cellular component of the innate immune system. A total absence of neutrophils or a significant decrease in their number leads to severe immunodeficiency. A mature neutrophil, released from the bone marrow, should be able to migrate from the blood towards the tissues, following a chemotactic gradient to a pathogen. In order to be neutralized, this pathogen has to be recognized, phagocytosed, and destroyed by lytic enzymes contained in the neutrophils granules and reactive oxygen species formed by the enzyme complex NADPH oxidase. Rare genetic defects leading to the loss of each one of these biological properties of the neutrophil have been described and are associated with immunodeficiency. This review provides a summary of the normal development and biological functions of neutrophils and describes the diseases caused by defects in neutrophil number and function.
Related JoVE Video
Genome-wide association study identifies FCGR2A as a susceptibility locus for Kawasaki disease.
Nat. Genet.
PUBLISHED: 05-27-2011
Show Abstract
Hide Abstract
Kawasaki disease is a systemic vasculitis of unknown etiology, with clinical observations suggesting a substantial genetic contribution to disease susceptibility. We conducted a genome-wide association study and replication analysis in 2,173 individuals with Kawasaki disease and 9,383 controls from five independent sample collections. Two loci exceeded the formal threshold for genome-wide significance. The first locus is a functional polymorphism in the IgG receptor gene FCGR2A (encoding an H131R substitution) (rs1801274; P = 7.35 × 10(-11), odds ratio (OR) = 1.32), with the A allele (coding for histadine) conferring elevated disease risk. The second locus is at 19q13, (P = 2.51 × 10(-9), OR = 1.42 for the rs2233152 SNP near MIA and RAB4B; P = 1.68 × 10(-12), OR = 1.52 for rs28493229 in ITPKC), which confirms previous findings(1). The involvement of the FCGR2A locus may have implications for understanding immune activation in Kawasaki disease pathogenesis and the mechanism of response to intravenous immunoglobulin, the only proven therapy for this disease.
Related JoVE Video
Genome-wide linkage and association mapping identify susceptibility alleles in ABCC4 for Kawasaki disease.
J. Med. Genet.
PUBLISHED: 05-13-2011
Show Abstract
Hide Abstract
Kawasaki disease (KD) is a self limited vasculitis in which host genetics plays a prominent role. To further the understanding of the role of host genetics in KD, a three-stage genetic study was conducted that began with a family linkage study and ultimately involved more than 3000 individuals to identify new genetic contributions to KD susceptibility.
Related JoVE Video
Altered intracellular localization and mobility of SBDS protein upon mutation in Shwachman-Diamond syndrome.
PLoS ONE
PUBLISHED: 05-09-2011
Show Abstract
Hide Abstract
Shwachman-Diamond Syndrome (SDS) is a rare inherited disease caused by mutations in the SBDS gene. Hematopoietic defects, exocrine pancreas dysfunction and short stature are the most prominent clinical features. To gain understanding of the molecular properties of the ubiquitously expressed SBDS protein, we examined its intracellular localization and mobility by live cell imaging techniques. We observed that SBDS full-length protein was localized in both the nucleus and cytoplasm, whereas patient-related truncated SBDS protein isoforms localize predominantly to the nucleus. Also the nucleo-cytoplasmic trafficking of these patient-related SBDS proteins was disturbed. Further studies with a series of SBDS mutant proteins revealed that three distinct motifs determine the intracellular mobility of SBDS protein. A sumoylation motif in the C-terminal domain, that is lacking in patient SBDS proteins, was found to play a pivotal role in intracellular motility. Our structure-function analyses provide new insight into localization and motility of the SBDS protein, and show that patient-related mutant proteins are altered in their molecular properties, which may contribute to the clinical features observed in SDS patients.
Related JoVE Video
Idiopathic CD4+ T lymphopenia without autoimmunity or granulomatous disease in the slipstream of RAG mutations.
Blood
PUBLISHED: 04-18-2011
Show Abstract
Hide Abstract
A girl presented during childhood with a single course of extensive chickenpox and moderate albeit recurrent pneumonia in the presence of idiopathic CD4+ T lymphocytopenia (ICL). Her clinical condition remained stable over the past 10 years without infections, any granulomatous disease, or autoimmunity. Immunophenotyping demonstrated strongly reduced naive T and B cells with intact proliferative capacity. Antibody reactivity on in vivo immunizations was normal. T-cell receptor-V? repertoire was polyclonal with a very low content of T-cell receptor excision circles (TRECs). Kappa-deleting recombination excision circles (KRECs) were also abnormal in the B cells. Both reflect extensive in vivo proliferation. Patient-derived CD34+ hematopoietic stem cells could not repopulate RAG2(-/-)IL2R?c(-/-) mice, indicating the lymphoid origin of the defect. We identified 2 novel missense mutations in RAG1 (p.Arg474Cys and p.Leu506Phe) resulting in reduced RAG activity. This report gives the first genetic clue for ICL and extends the clinical spectrum of RAG mutations from severe immune defects to an almost normal condition.
Related JoVE Video
Current concepts of hyperinflammation in chronic granulomatous disease.
Clin. Dev. Immunol.
PUBLISHED: 03-24-2011
Show Abstract
Hide Abstract
Chronic granulomatous disease (CGD) is the most common inherited disorder of phagocytic functions, caused by genetic defects in the leukocyte nicotinamide dinucleotide phosphate (NADPH) oxidase. Consequently, CGD phagocytes are impaired in destroying phagocytosed microorganisms, rendering the patients susceptible to bacterial and fungal infections. Besides this immunodeficiency, CGD patients suffer from various autoinflammatory symptoms, such as granuloma formation in the skin or urinary tract and Crohn-like colitis. Owing to improved antimicrobial treatment strategies, the majority of CGD patients reaches adulthood, yet the autoinflammatory manifestations become more prominent by lack of causative treatment options. The underlying pathomechanisms driving hyperinflammatory reactions in CGD are poorly understood, but recent studies implicate reduced neutrophil apoptosis and efferocytosis, dysbalanced innate immune receptors, altered T-cell surface redox levels, induction of Th17 cells, the enzyme indolamine-2,3-dioxygenase (IDO), impaired Nrf2 activity, and inflammasome activation. Here we discuss immunological mechanisms of hyperinflammation and their potential therapeutic implications in CGD.
Related JoVE Video
[Kawasaki disease: description of a Dutch cohort of 392 patients].
Ned Tijdschr Geneeskd
PUBLISHED: 03-23-2011
Show Abstract
Hide Abstract
To describe the patient characteristics, management and cardiovascular sequelae of Kawasaki disease (KD) in patients taking part in a multidisciplinary follow-up in the Emma Childrens Hospital during the period January 1999-June 2010.
Related JoVE Video
Transforming growth factor-beta signaling pathway in patients with Kawasaki disease.
Circ Cardiovasc Genet
PUBLISHED: 12-02-2010
Show Abstract
Hide Abstract
Transforming growth factor (TGF)-? is a multifunctional peptide that is important in T-cell activation and cardiovascular remodeling, both of which are important features of Kawasaki disease (KD). We postulated that variation in TGF-? signaling might be important in KD susceptibility and disease outcome.
Related JoVE Video
Induction of regulatory T cells by macrophages is dependent on production of reactive oxygen species.
Proc. Natl. Acad. Sci. U.S.A.
PUBLISHED: 09-22-2010
Show Abstract
Hide Abstract
The phagocyte NAPDH-oxidase complex consists of several phagocyte oxidase (phox) proteins, generating reactive oxygen species (ROS) upon activation. ROS are involved in the defense against microorganisms and also in immune regulation. Defective ROS formation leads to chronic granulomatous disease (CGD) with increased incidence of autoimmunity and disturbed resolution of inflammation. Because regulatory T cells (Tregs) suppress autoimmune T-cell responses and are crucial in down-regulating immune responses, we hypothesized that ROS deficiency may lead to decreased Treg induction. Previously, we showed that in p47(phox)-mutated mice, reconstitution of macrophages (Mph) with ROS-producing capacity was sufficient to protect the mice from arthritis. Now, we present evidence that Mph-derived ROS induce Tregs. In vitro, we showed that Mph ROS-dependently induce Treg, using an NADPH-oxidase inhibitor. This finding was confirmed genetically: rat or human CGD Mph with mutated p47(phox) or gp91(phox) displayed hampered Treg induction and T-cell suppression. However, basal Treg numbers in these subjects were comparable to those in controls, indicating a role for ROS in induction of peripheral Tregs. Induction of allogeneic delayed-type hypersensitivity with p47(phox)-mutated Mph confirmed the importance of Mph-derived ROS in Treg induction in vivo. We conclude that NAPDH oxidase activity in Mph is important for the induction of Tregs to regulate T cell-mediated inflammation.
Related JoVE Video
Evidence of impact of maternal HIV infection on immunoglobulin levels in HIV-exposed uninfected children.
AIDS Res. Hum. Retroviruses
PUBLISHED: 08-20-2010
Show Abstract
Hide Abstract
HIV infection affects B cell function and is associated with increased immunoglobulin levels, including in HIV-infected pregnant women. It is unknown if maternal HIV infection affects immunoglobulins in their uninfected children. We investigated this using prospective longitudinal data from children born to HIV-infected women enrolled in the European Collaborative Study (ECS). Data from children enrolled in the European Paediatric Hepatitis C Virus Network (EPHN) were used as a comparison group. Associations between infant and maternal factors and child log(10) total IgG, IgM, and IgA levels were quantified in linear regression analyses. A total of 1751 HIV-uninfected (ECS) and 167 HCV-uninfected children (EPHN) were included. HIV-uninfected children had significantly higher IgG, IgM, and IgA levels than HCV-uninfected children up to at least 24 months. Among HIV-exposed uninfected children, IgG levels from birth until 5 years of age were correlated with increased maternal IgG levels. ART exposure in fetal and early neonatal life was associated with lower IgG. These findings indicate alterations in immunoglobulin levels in uninfected children born to HIV-infected women, suggesting that fetal exposure to a chronically activated maternal immune system is associated with an altered humoral response.
Related JoVE Video
Severe congenital neutropenia in a multigenerational family with a novel neutrophil elastase (ELANE) mutation.
Ann. Hematol.
PUBLISHED: 08-02-2010
Show Abstract
Hide Abstract
We have analysed a family with nine congenital neutropenia patients in four generations, several of which we have studied in a long-term follow-up of over 25 years. The patients were mild to severe neutropenic and suffered from various recurrent bacterial infections. Mutations in the genes ELANE, CSF3R and GFI1 have been reported in patients with autosomal dominant congenital neutropenias. Using a small-scale linkage analysis with markers around the ELANE, CSF3R, CSF3 and GFI1 genes, we were able to determine that the disease segregated with markers around the ELANE gene. We identified a novel mutation in the ELANE gene in all of the affected family members that was not present in any of the healthy family members. The mutation leads to an A28S missense mutation in the mature protein. None of these patients developed leukaemia. This is the first truly multigenerational family with mutations in ELANE as unambiguous cause of severe congenital neutropenia SCN.
Related JoVE Video
Role of NADPH oxidase in endothelial ischemia/reperfusion injury in humans.
Circulation
PUBLISHED: 05-17-2010
Show Abstract
Hide Abstract
Reactive oxygen species have been implicated in the pathogenesis of ischemia/reperfusion (IR) injury. Recent studies suggest that NADPH oxidase may be a source of ROS during IR. Using an in vivo model of endothelial IR injury in the arm, we compared the response to IR in healthy volunteers with that in patients with chronic granulomatous disease. These patients have a molecular lesion in a subunit of NADPH oxidase that renders the enzyme inactive.
Related JoVE Video
Human NLRP3 inflammasome activation is Nox1-4 independent.
Blood
PUBLISHED: 04-20-2010
Show Abstract
Hide Abstract
The NLRP3 inflammasome can be activated by pathogen-associated molecular patterns or endogenous danger-associated molecular patterns. The activation of the NLRP3 inflammasome results in proteolytic activation and secretion of cytokines of the interleukin-1 (IL-1) family. The precise mode of activation of the NLRP3 inflammasome is still elusive, but has been postulated to be mediated by reactive oxygen species (ROS) generated by an NADPH oxidase. Using primary cells from chronic granulomatous disease (CGD) patients lacking expression of p22(phox), a protein that is required for the function of Nox1-4, we show that cells lacking NADPH oxidase activity are capable of secreting normal amounts of IL-1beta. Thus, we provide evidence that activation of the NLRP3 inflammasome does not depend on ROS generated from an NADPH oxidase.
Related JoVE Video
Toll-like receptor-induced reactivity and strongly potentiated IL-8 production in granulocytes mobilized for transfusion purposes.
Blood
PUBLISHED: 03-30-2010
Show Abstract
Hide Abstract
Transfusion of granulocytes from granulocyte-colony stimulating factor (G-CSF)/dexamethasone (dexa)-treated donors can be beneficial for neutropenic recipients that are refractory to antimicrobial therapy. G-CSF/dexa treatment not only increases the number of circulating neutrophils but also affects their gene expression. Because of the intended transfusion of these granulocytes into patients who are severely ill, it is of importance to establish to what extent mobilization affects the cellular behavior of neutrophils. Here, we studied the effects of mobilization on Toll-like receptor (TLR)-mediated responses. Mobilized granulocytes displayed increased gene and protein expression of TLR2, TLR4, TLR5, and TLR8. Although mobilized granulocytes displayed normal priming of nicotinamide adenine dinucleotide phosphate oxidase activity and a slight increase in adhesion in response to TLR stimulation, these cells produced massive amounts of interleukin-8 (IL-8), in particular to TLR2 and TLR8 stimulation. The increase in IL-8 release occurred despite reduced IL-8 mRNA levels in the donor granulocytes after in vivo G-CSF/dexa treatment, indicating that the enhanced TLR-induced IL-8 production was largely determined by posttranscriptional regulation. In summary, granulocytes mobilized for transfusion purposes show enhanced TLR responsiveness in cytokine production, which is anticipated to be beneficial for the function of these cells on transfusion into patients.
Related JoVE Video
Nontuberculous mycobacterial cervicofacial lymphadenitis in children from the multicenter, randomized, controlled trial in The Netherlands: relevance of polymorphisms in candidate host immunity genes.
Int. J. Pediatr. Otorhinolaryngol.
PUBLISHED: 01-27-2010
Show Abstract
Hide Abstract
The annual incidence of nontuberculous mycobacterial (NTM) cervicofacial lymphadenitis in otherwise healthy children is unexpectedly high (8 per million). It mostly arises as localized cervicofacial lymphadenitis. Previous research has suggested environmental risk factors for oral exposure to NTM and a temporal association with eruption of teeth. We studied 22 polymorphisms in relevant candidate genes, some related to periodontitis, in children with NTM lymphadenitis. We also tested for the most common mutation in IFNGR1.
Related JoVE Video
Genome-wide association study identifies variants in the CFH region associated with host susceptibility to meningococcal disease.
Nat. Genet.
PUBLISHED: 01-21-2010
Show Abstract
Hide Abstract
Meningococcal disease is an infection caused by Neisseria meningitidis. Genetic factors contribute to host susceptibility and progression to disease, but the genes responsible for disease development are largely unknown. We report here a genome-wide association study for host susceptibility to meningococcal disease using 475 individuals with meningococcal disease (cases) and 4,703 population controls from the UK. We performed, in Western European and South European cohorts (consisting of 968 cases and 1,376 controls), two replication studies for the most significant SNPs. A cluster of complement factor SNPs replicated independently in both cohorts, including SNPs within complement factor H (CFH) (rs1065489 (p.936D
Related JoVE Video

What is Visualize?

JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.

How does it work?

We use abstracts found on PubMed and match them to JoVE videos to create a list of 10 to 30 related methods videos.

Video X seems to be unrelated to Abstract Y...

In developing our video relationships, we compare around 5 million PubMed articles to our library of over 4,500 methods videos. In some cases the language used in the PubMed abstracts makes matching that content to a JoVE video difficult. In other cases, there happens not to be any content in our video library that is relevant to the topic of a given abstract. In these cases, our algorithms are trying their best to display videos with relevant content, which can sometimes result in matched videos with only a slight relation.