While the antigenic specificity and pathogenic relevance of immunologic reactivity to gluten in celiac disease have been extensively researched, the immune response to nongluten proteins of wheat has not been characterized. We aimed to investigate the level and molecular specificity of antibody response to wheat nongluten proteins in celiac disease. Serum samples from patients and controls were screened for IgG and IgA antibody reactivity to a nongluten protein extract from the wheat cultivar Triticum aestivum Butte 86. Antibodies were further analyzed for reactivity to specific nongluten proteins by two-dimensional gel electrophoresis and immunoblotting. Immunoreactive molecules were identified by tandem mass spectrometry. Compared with healthy controls, patients exhibited significantly higher levels of antibody reactivity to nongluten proteins. The main immunoreactive nongluten antibody target proteins were identified as serpins, purinins, ?-amylase/protease inhibitors, globulins, and farinins. Assessment of reactivity toward purified recombinant proteins further confirmed the presence of antibody response to specific antigens. The results demonstrate that, in addition to the well-recognized immune reaction to gluten, celiac disease is associated with a robust humoral response directed at a specific subset of the nongluten proteins of wheat.
Schizophrenia is a complex brain disorder that may be accompanied by idiopathic inflammation. Classic central nervous system (CNS) inflammatory disorders such as viral encephalitis or multiple sclerosis can be characterized by incongruent serum and cerebrospinal fluid (CSF) IgG due in part to localized intrathecal synthesis of antibodies. The dietary antigens, wheat gluten and bovine milk casein, can induce a humoral immune response in susceptible individuals with schizophrenia, but the correlation between the food-derived serological and intrathecal IgG response is not known. Here, we measured IgG to wheat gluten and bovine milk casein in matched serum and CSF samples from 105 individuals with first-episode schizophrenia (n=75 antipsychotic-naïve), and 61 controls. We found striking correlations in the levels of IgG response to dietary proteins between serum and CSF of schizophrenia patients, but not controls (schizophrenia, R(2)=0.34-0.55, p?0.0001; controls R(2)=0.05-0.06, p>0.33). A gauge of blood-CSF barrier permeability and CSF flow rate, the CSF-to-serum albumin ratio, was significantly elevated in cases compared to controls (p?0.001-0.003). Indicators of intrathecal IgG production, the CSF IgG index and the specific Antibody Index, were not significantly altered in schizophrenia compared to controls. Thus, the selective diffusion of bovine milk casein and wheat gluten antibodies between serum and CSF in schizophrenia may be the function of a low-level anatomical barrier dysfunction or altered CSF flow rate, which may be transient in nature.
Increased immunoglobulin G (IgG) response to dietary antigens can be associated with gastrointestinal dysfunction and autoimmunity. The underlying processes contributing to these adverse reactions remain largely unknown, and it is likely that genetic factors play a role. Here, we estimate heritability and attempt to localize genetic factors influencing IgG antibody levels against food-derived antigens using an integrative genomics approach. IgG antibody levels were determined by ELISA in >1,300 Mexican Americans for the following food antigens: wheat gliadin; bovine casein; and two forms of bovine serum albumin (BSA-a and BSA-b). Pedigree-based variance components methods were used to estimate additive genetic heritability (h(2) ), perform genome-wide association analyses, and identify transcriptional signatures (based on 19,858 transcripts from peripheral blood lymphocytes). Heritability estimates were significant for all traits (0.15-0.53), and shared environment (based on shared residency among study participants) was significant for casein (0.09) and BSA-a (0.33). Genome-wide significant evidence of association was obtained only for antibody to gliadin (P = 8.57 × 10(-8) ), mapping to the human leukocyte antigen II region, with HLA-DRA and BTNL2 as the best candidate genes. Lack of association of known celiac disease risk alleles HLA-DQ2.5 and -DQ8 with antigliadin antibodies in the studied population suggests a separate genetic etiology. Significant transcriptional signatures were found for all IgG levels except BSA-b. These results demonstrate that individual genetic differences contribute to food antigen antibody measures in this population. Further investigations may elucidate the underlying immunological processes involved.
IgA nephropathy is the most common form of primary glomerulonephritis worldwide. Mucosal infections and food antigens, including wheat gluten, have been proposed as potential contributing environmental factors. Increased immune reactivity to gluten and/or association with celiac disease, an autoimmune disorder triggered by ingestion of gluten, have been reported in IgA nephropathy. However, studies are inconsistent about this association. We aimed to evaluate the proposed link between IgA nephropathy and celiac disease or immune reactivity to gluten by conducting a comprehensive analysis of associated serologic markers in cohorts of well-characterized patients and controls. Study participants included patients with biopsy-proven IgA nephropathy (n?=?99), unaffected controls of similar age, gender, and race (n?=?96), and patients with biopsy-proven celiac disease (n?=?30). All serum specimens were tested for IgG and IgA antibodies to native gliadin and deamidated gliadin, as well as IgA antibody to transglutaminase 2 (TG2). Anti-TG2 antibody-positive nephropathy patients and unaffected controls were subsequently tested for IgA anti-endomysial antibody and genotyped for celiac disease-associated HLA-DQ2 and -DQ8 alleles. In comparison to unaffected controls, there was not a statistically significant increase in IgA or IgG antibody reactivity to gliadin in individuals with IgA nephropathy. In addition, the levels of celiac disease-specific serologic markers, i.e., antibodies to deamidated gliadin and TG2, did not differ between IgA nephropathy patients and unaffected controls. Results of the additional anti-endomysial antibody testing and HLA genotyping were corroborative. The data from this case-control study do not reveal any evidence to suggest a significant role for celiac disease or immune reactivity to gluten in IgA nephropathy.
Forty of 54 children with autism were reported to have an elevated antibody response to GM1 ganglioside that correlated with disease severity.(1) Antiganglioside autoantibodies, especially those directed at GM1, are known to be associated with and play a pathogenic role in some immune-mediated peripheral neuropathies.(2,3) The presumed link between autism and anti-GM1 antibodies, therefore, implies that testing may identify a sizable subset of patients who would benefit from immunomodulatory therapy. To evaluate the proposed association between autism and anti-GM1 antibodies, serum samples from children diagnosed with autism by strict clinical criteria and those without autism were analyzed using a standard, validated immunoassay protocol.
Immune sensitivity to wheat glutens and bovine milk caseins may affect a subset of individuals with bipolar disorder. Digested byproducts of these foods are exorphins that have the potential to impact brain physiology through action at opioid receptors. Inflammation in the gastrointestinal (GI) tract might accelerate exposure of food antigens to systemic circulation and help explain elevated gluten and casein antibody levels in individuals with bipolar disorder.
Gastrointestinal symptoms are a common feature in children with autism, drawing attention to a potential association with celiac disease or gluten sensitivity. However, studies to date regarding the immune response to gluten in autism and its association with celiac disease have been inconsistent. The aim of this study was to assess immune reactivity to gluten in pediatric patients diagnosed with autism according to strict criteria and to evaluate the potential link between autism and celiac disease.
Patients with post-Lyme disease syndrome (PLDS) report persistent symptoms of pain, fatigue, and/or concentration and memory disturbances despite antibiotic treatment for Lyme borreliosis. The etiopathogenesis of these symptoms remains unknown and no effective therapies have been identified. We sought to examine the antiborrelia antibody profile in affected patients with the aim of finding clues to the mechanism of the syndrome and its relationship to the original spirochetal infection. Serum specimens from 54 borrelia-seropositive PLDS patients were examined for antibodies to Borrelia burgdorferi proteins p18, p25, p28, p30, p31, p34, p39, p41, p45, p58, p66, p93, and VlsE by automated immunoblotting and software-assisted band analysis. The presence of serum antibodies to the 31-kDa band was further investigated by examination of reactivity against purified recombinant OspA protein. Control specimens included sera from 14 borrelia-seropositive individuals with a history of early localized or disseminated Lyme disease who were symptom free (post-Lyme healthy group), as well as 20 healthy individuals without serologic evidence or history of Lyme disease. In comparison to the post-Lyme healthy group, higher frequencies of antibodies to p28 (P < 0.05), p30 (P < 0.05), p31 (P < 0.0001), and p34 (P < 0.05) proteins were found in the PLDS group. Assessment of antibody reactivity to recombinant OspA confirmed the presence of elevated levels in PLDS patients (P < 0.005). The described antiborrelia antibody profile in PLDS offers clues about the course of the antecedent infection in affected patients, which may be useful for understanding the pathogenic mechanism of the disease.
Increased immune sensitivity to dietary gluten proteins has been reported in schizophrenia but has not been studied in bipolar disorder. In this study, we examine the levels of antibody reactivity to gliadin, deamidated gliadin, and tissue transglutaminase (tTG) in individuals with bipolar disorder and compare these levels to those in individuals who do not have any history of psychiatric disorder.
The VlsE lipoprotein of Borrelia burgdorferi elicits a strong immune response during the course of Lyme disease. The present study was aimed at characterization of the epitopes of VlsE targeted by the antibody response in patients with post-Lyme disease syndrome, a condition characterized by persisting symptoms of pain, fatigue, and/or neurocognitive impairment despite antibiotic treatment of B. burgdorferi infection. Epitope mapping was carried out using microarrays that contained synthesized overlapping peptides covering the full sequence of VlsE from B. burgdorferi B31. In addition to the previously characterized IR6 region in the variable domain, specific sequences in the N- and C-terminal invariable domains of VlsE were found to be major B cell epitopes in affected patients. The crystal structure of VlsE indicated that the newly described epitopes form a contiguous region in the surface-exposed membrane-proximal part of the monomeric form of the protein.
Some Lyme disease patients report debilitating chronic symptoms of pain, fatigue, and cognitive deficits despite recommended courses of antibiotic treatment. The mechanisms responsible for these symptoms, collectively referred to as post-Lyme disease syndrome (PLS) or chronic Lyme disease, remain unclear. We investigated the presence of immune system abnormalities in PLS by assessing the levels of antibodies to neural proteins in patients and controls. Serum samples from PLS patients, post-Lyme disease healthy individuals, patients with systemic lupus erythematosus, and normal healthy individuals were analyzed for anti-neural antibodies by immunoblotting and immunohistochemistry. Anti-neural antibody reactivity was found to be significantly higher in the PLS group than in the post-Lyme healthy (p<0.01) and normal healthy (p<0.01) groups. The observed heightened antibody reactivity in PLS patients could not be attributed solely to the presence of cross-reactive anti-borrelia antibodies, as the borrelial seronegative patients also exhibited elevated anti-neural antibody levels. Immunohistochemical analysis of PLS serum antibody activity demonstrated binding to cells in the central and peripheral nervous systems. The results provide evidence for the existence of a differential immune system response in PLS, offering new clues about the etiopathogenesis of the disease that may prove useful in devising more effective treatment strategies.
A link between celiac disease and schizophrenia has been postulated for several years, based primarily on reports of elevated levels of antibody to gliadin in patients. We sought to examine the proposed connection between schizophrenia and celiac disease by characterizing the molecular specificity and mechanism of the anti-gliadin immune response in a subset of individuals with schizophrenia. Blood samples from individuals with schizophrenia and elevated anti-gliadin antibody titer were examined for celiac disease-associated biomarkers, including antibodies to transglutaminase 2 (TG2) enzyme and deamidated gliadin peptides, as well as the HLA-DQ2 and -DQ8 MHC genes. The anti-gliadin antibody response was further characterized through examination of reactivity towards chromatographically separated gluten proteins. Target proteins of interest were identified by peptide mass mapping. In contrast to celiac disease patients, an association between the anti-gliadin immune response and anti-TG2 antibody or HLA-DQ2 and -DQ8 markers was not found in individuals with schizophrenia. In addition, the majority of individuals with schizophrenia and anti-gliadin antibody did not exhibit antibody reactivity to deamidated gliadin peptides. Further characterization of the antibody specificity revealed preferential reactivity towards different gluten proteins in the schizophrenia and celiac disease groups. These findings indicate that the anti-gliadin immune response in schizophrenia has a different antigenic specificity from that in celiac disease and is independent of the action of transglutaminase enzyme and HLA-DQ2/DQ8. Meanwhile, the presence of elevated levels of antibodies to specific gluten proteins points to shared immunologic abnormalities in a subset of schizophrenia patients. Further characterization and understanding of the immune response to gluten in schizophrenia may provide novel insights into the etiopathogenesis of specific disease phenotypes.
Gluten sensitivity may affect disease pathogenesis in a subset of individuals who have schizophrenia, bipolar disorder or autism. Exposure to Toxoplasma gondii is a known risk factor for the development of schizophrenia, presumably through a direct pathological effect of the parasite on brain and behavior. A co-association of antibodies to wheat gluten and to T. gondii in individuals with schizophrenia was recently uncovered, suggesting a coordinated gastrointestinal means by which T. gondii and dietary gluten might generate an immune response. Here, we evaluated the connection between these infectious- and food-based antigens in mouse models. BALB/c mice receiving a standard wheat-based rodent chow were infected with T. gondii via intraperitoneal, peroral and prenatal exposure methods. Significant increases in the levels of anti-gluten IgG were documented in all infected mice and in offspring from chronically infected dams compared to uninfected controls (repetitive measures ANOVAs, two-tailed t-tests, all p?0.00001). Activation of the complement system accompanied this immune response (p?0.002-0.00001). Perorally-infected females showed higher levels of anti-gluten IgG than males (p?0.009) indicating that T. gondii-generated gastrointestinal infection led to a significant anti-gluten immune response in a sex-dependent manner. These findings support a gastrointestinal basis by which two risk factors for schizophrenia, T. gondii infection and sensitivity to dietary gluten, might be connected to produce the immune activation that is becoming an increasingly recognized pathology of psychiatric disorders.
Following antibiotic treatment for Lyme disease, some patients report persistent or relapsing symptoms of pain, fatigue, and/or cognitive deficits. Factors other than active infection, including immune abnormalities, have been suggested, but few clues regarding mechanism have emerged. Furthermore, the effect of antibiotic treatment on immune response in affected individuals remains unknown. In this study, a longitudinal analysis of specific immune markers of interest was carried out in patients with a history of Lyme disease and persistent objective memory impairment, prior to and following treatment with either ceftriaxone or placebo. IFN? activity was measured by detection of serum-induced changes in specific target genes, using a functional cell-based assay and quantitative real-time PCR. Level and pattern of antibody reactivity to brain antigens and to Borrelia burgdorferi proteins were analyzed by ELISA and immunoblotting. Sera from the patient cohort induced significantly higher expression of IFIT1 and IFI44 target genes than those from healthy controls, indicating increased IFN? activity. Antibody reactivity to specific brain and borrelial proteins was significantly elevated in affected patients. IFN? activity and antibody profile did not change significantly in response to ceftriaxone. The heightened antibody response implies enhanced immune stimulation, possibly due to prolonged exposure to the organism prior to the initial diagnosis and antibiotic treatment of Lyme disease. The increase in IFN? activity is suggestive of a mechanism contributing to the ongoing neuropsychiatric symptoms.
Gluten sensitivity has been best recognized and understood in the context of two conditions, celiac disease and wheat allergy. However, some individuals complain of symptoms in response to ingestion of "gluten," without histologic or serologic evidence of celiac disease or wheat allergy. The term non-celiac gluten sensitivity (NCGS) has been suggested for this condition, although a role for gluten proteins as the sole trigger of the associated symptoms remains to be established. This article reviews the available information regarding symptomatology, epidemiology and genetics, serology and histology, and in vitro and in vivo experimental data on the pathophysiology of NCGS.
Immune system factors including complement pathway activation are increasingly linked to the etiology and pathophysiology of schizophrenia. Complement protein, C1q, binds to and helps to clear immune complexes composed of immunoglobulins coupled to antigens. The antigenic stimuli for C1q activation in schizophrenia are not known. Food sensitivities characterized by elevated IgG antibodies to bovine milk caseins and wheat glutens have been reported in individuals with schizophrenia. Here, we examined the extent to which these food products might comprise the antigen component of complement C1q immune complexes in individuals with recent onset schizophrenia (n=38), non-recent onset schizophrenia (n=61) and non-psychiatric controls (n=63). C1q seropositivity was significantly associated with both schizophrenia groups (recent onset, odds ratio (OR)=8.02, p?0.008; non-recent onset, OR=3.15, p?0.03) compared to controls (logistic regression models corrected for age, sex, race and smoking status). Casein- and/or gluten-IgG binding to C1q was significantly elevated in the non-recent onset group compared to controls (OR=4.36, p?0.01). Significant amounts of C1q-casein/gluten-related immune complexes and C1q correlations with a marker for gastrointestinal inflammation in non-recent onset schizophrenia suggests a heightened rate of food antigens in the systemic circulation, perhaps via a disease-associated altered intestinal permeability. In individuals who are in the early stages of disease onset, C1q activation may reflect the formation of immune complexes with non-casein- or non-gluten-related antigens, the presence of C1q autoantibodies, and/or a dissociated state of immune complex components. In conclusion, complement activation may be a useful biomarker to diagnose schizophrenia early during the course of the disease. Future prospective studies should evaluate the impacts of casein- and gluten-free diets on C1q activation in schizophrenia.
Immune factors are implicated in normal brain development and in brain disorder pathogenesis. Pathogen infection and food antigen penetration across gastrointestinal barriers are means by which environmental factors might affect immune-related neurodevelopment. Here, we test if gastrointestinal inflammation is associated with schizophrenia and therefore, might contribute to bloodstream entry of potentially neurotropic milk and gluten exorphins and/or immune activation by food antigens. IgG antibodies to Saccharomyces cerevisiae (ASCA, a marker of intestinal inflammation), bovine milk casein, wheat-derived gluten, and 6 infectious agents were assayed. Cohort 1 included 193 with non-recent onset schizophrenia, 67 with recent onset schizophrenia and 207 non-psychiatric controls. Cohort 2 included 103 with first episode schizophrenia, 40 of whom were antipsychotic-naïve. ASCA markers were significantly elevated and correlated with food antigen antibodies in recent onset and non-recent onset schizophrenia compared to controls (p?0.00001-0.004) and in unmedicated individuals with first episode schizophrenia compared to those receiving antipsychotics (p?0.05-0.01). Elevated ASCA levels were especially evident in non-recent onset females (p?0.009), recent onset males (p?0.01) and in antipsychotic-naïve males (p?0.03). Anti-food antigen antibodies were correlated to antibodies against Toxoplasma gondii, an intestinally-infectious pathogen, particularly in males with recent onset schizophrenia (p?0.002). In conclusion, gastrointestinal inflammation is a relevant pathology in schizophrenia, appears to occur in the absence of but may be modified by antipsychotics, and may link food antigen sensitivity and microbial infection as sources of immune activation in mental illness.
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