The adaptive immune response in celiac disease. Semin Immunopathol. 2012;34:523-540. [PMID: 22535446 DOI: 10.1007/s00281-012-0314-z]

Randomized, Placebo Controlled Trial of Experimental Hookworm Infection for Improving Gluten Tolerance in Celiac Disease

INTRODUCTION:

Celiac disease is an autoimmune disorder where intestinal immunopathology arises after gluten consumption. Previous studies suggested that hookworm infection restores gluten tolerance; however, these studies were small (n = 12) and not placebo controlled.

METHODS:

We undertook a randomized, placebo-controlled trial of hookworm infection in 54 people with celiac disease. The 94-week study involved treatment with either 20 or 40 Necator americanus third-stage larvae (L3-20 or L3-40) or placebo, followed by escalating gluten consumption (50 mg/d for 12 weeks, 1 g intermittent twice weekly for 12 weeks, 2 g/d sustained for 6 weeks, liberal diet for 1 year).

RESULTS:

Successful study completion rates at week 42 (primary outcome) were similar in each group (placebo: 57%, L3-20: 37%, and L3-40: 44%; P = 0.61), however gluten-related adverse events were significantly reduced in hookworm-treated participants: Median (range) adverse events/participant were as follows: placebo, 4 (1–9); L3-20, 1 (0–9); and L3-40, 0 (0–3) (P = 0.019). Duodenal villous height:crypt depth deteriorated similarly compared with their enrolment values in each group (mean change [95% confidence interval]: placebo, −0.6 [−1.3 to 0.2]; L3-20, −0.5 [−0.8 to 0.2]; and L3-40, −1.1 [−1.8 to 0.4]; P = 0.12). A retrospective analysis revealed that 9 of the 40 L3-treated participants failed to establish hookworm infections. Although week 42 completion rates were similar in hookworm-positive vs hookworm-negative participants (48% vs 44%, P = 0.43), quality of life symptom scores were lower in hookworm-positive participants after intermittent gluten challenge (mean [95% confidence interval]: 38.9 [33.9–44] vs 45.9 [39.2–52.6]).

DISCUSSION:

Hookworm infection does not restore tolerance to sustained moderate consumption of gluten (2 g/d) but was associated with improved symptom scores after intermittent consumption of lower, intermittent gluten doses.

Challenges of Monitoring the Gluten-Free Diet Adherence in the Management and Follow-Up of Patients with Celiac Disease

Celiac disease (CD) is a chronic gluten-responsive immune mediated enteropathy and is treated with a gluten-free diet (GFD). However, a strict diet for life is not easy due to the ubiquitous nature of gluten. This review aims at examining available evidence on the degree of adherence to a GFD, the methods to assess it, and the barriers to its implementation. The methods for monitoring the adherence to a GFD are comprised of a dietary questionnaire, celiac serology, or clinical symptoms; however, none of these methods generate either a direct or an accurate measure of dietary adherence. A promising advancement is the development of tests that measure gluten immunogenic peptides in stools and urine. Causes of adherence/non-adherence to a GFD are numerous and multifactorial. Inadvertent dietary non-adherence is more frequent than intentional non-adherence. Cross-contamination of gluten-free products with gluten is a major cause of inadvertent non-adherence, while the limited availability, high costs, and poor quality of certified gluten-free products are responsible for intentionally breaking a GFD. Therefore, several studies in the last decade have indicated that many patients with CD who follow a GFD still have difficulty controlling their diet and, therefore, regularly consume enough gluten to trigger symptoms and damage the small intestine.

Measures of gluten-related reactivity in children with autism spectrum disorders in the absence of overt gastrointestinal symptoms: a pilot study from the United Arab Emirates

Objectives

The aetiology of autism spectrum disorder (ASD) is multifactorial, sometimes genetic, and may be associated with abnormal immunological responses to peptides from proteins such as gluten. These peptides may cross the blood-brain barrier and affect neurotransmission, resulting in behavioural symptoms consistent with ASD. The aim of this study was to screen for markers of gluten-related immune reactivity in the absence of overt gastrointestinal symptoms in patients with ASD in the United Arab Emirates, a country associated with a high prevalence of ASD but lacking this type of research.

Methods

Patients diagnosed with ASD (using Diagnostic and Statistical Manual of Mental Disorders-IV-based criteria and Autism Diagnostic Observational Schedules) were compared with controls, regarding anti-tissue transglutaminase (tTG) immunoglobulin (Ig) A and anti-deamidated gliadin peptide (DGP) IgA levels.

Results

Sixty-six patients with ASD and 101 controls were included. Patients with ASD showed statistically significant lower anti-DGP IgA levels, but no significant difference in anti-tTG IgA levels, versus healthy controls. Correlations between immunological data and clinical symptoms were synergistic, but not statistically significant.

Conclusion

ASD may be associated with reduced levels of anti-DGP IgA.

The Protective Effects of the Ethyl Acetate Part of Er MiaoSan on Adjuvant Arthritis Rats by Regulating the Function of Bone Marrow-Derived Dendritic Cells

Aims. The aim of this study was to evaluate the protective effects of Er Miao San (EMS) and the regulative function of bone marrow-derived dendritic cells (BMDCs) on adjuvant arthritis (AA) in rats. Methods. The ethyl acetate part of EMS (3 g/kg, 1.5 g/kg, and 0.75 g/kg) was orally administered from day 15 after immunization to day 29. The polyarthritis index and paw swelling were measured, the ankle joint pathological changes were observed using hematoxylin-eosin (HE) staining, and the spleen and thymus index were determined. Moreover, T and B cell proliferation were determined using the CCK-8 assay. The expression of BMDC surface costimulatory molecules and inflammatory factors were determined using flow cytometry and ELISA kits, respectively. Results. Compared with the AA model rats, the ethyl acetate fraction of EMS obviously reduced paw swelling (from 1.0 to 0.7) and the polyarthritis index (from 12 to 9) $\left(P<0.01\right)$ and improved the severity of histopathology $\left(P<0.01\right)$ . The treatment using ethyl acetate fraction of EMS significantly reduced the spleen and thymus index $\left(P<0.01\right)$ and inhibited T and B cell proliferation $\left(P<0.01\right)$ . Moreover, EMS significantly modulated the expression of surface costimulatory molecules in BMDCs, including CD40, CD80, CD86, and major histocompatibility complex class II (MHC-II) $\left(P<0.01\right)$ . The results also showed that the ethyl acetate part of EMS significant inhibited the levels of proinflammatory cytokines interleukin- (IL-) 23 tumor necrosis factor- (TNF-) α and inflammatory factor prostaglandin (PG) E2 in the supernatant of BMDCs. However, the level of anti-inflammatory cytokine IL-10 was significantly increased $\left(P<0.01\right)$ . Conclusion. These results suggest that the ethyl acetate part of EMS has better protective effects on AA rats, probably by regulating the function of BMDCs and modulating the balance of cytokines.

High-resolution genotyping indicates that children with type 1 diabetes and celiac disease share three HLA class II loci in DRB3, DRB4 and DRB5 genes

Type 1 diabetes (T1D) and celiac disease (CD) share common genetic loci, mainly within the human leukocyte antigen (HLA) class II complex. Extended genotyping of HLA class II alleles and their potential risk for developing both diseases remains to be studied. The present study compared extended HLA-class II gene polymorphisms in children with T1D, CD, and a subgroup diagnosed with both diseases (T1D w/CD). Next-generation targeted sequencing (NGTS) of HLA-DRB3, DRB4, DRB5, DRB1, DQA1, DQB1, DPA1, and DPB1 alleles from DNA collected from 68 T1D, 219 CD, and seven T1D w/CD patients were compared with 636 HLA-genotyped Swedish children from the general population selected as controls. In comparison to controls, the DRB4*01:03:01 allele occurred more frequently in T1D w/CD (odds ratio (OR) = 7.84; 95% confidence interval (95% CI) = (2.24, 34.5), P = 0.0002) and T1D (OR = 3.86; 95% CI, (2.69, 5.55), P = 1.07 × 10^-14 ), respectively. The DRB3*01:01:02 allele occurred more frequently in CD as compared to controls (OR = 7.87; 95% CI, (6.17, 10.03), P = 4.24 × 10^-71 ), but less frequently in T1D (OR = 2.59; 95% CI, (1.76, 3.81), P = 7.29 × 10^-07 ) and T1D w/CD (OR = 0.87; 95% CI, (0.09, 3.96), P ≤ 0.999). The frequency of the DRB4*01:03:01-DRB1*04:01:01-DQA1*03:01:01-DQB1*03:02:01 (DR4-DQ8) haplotype was higher in T1D w/CD (OR = 12.88; 95% CI (4.35, 38.14) P = 3.75 × 10^-9 ), and moderately higher in T1D (OR = 2.13; 95% CI (1.18, 3.83) P = 0.01) compared with controls, but comparable in CD (OR = 1.45; 95% CI (0.94, 2.21), P = 0.08) and controls. Children with T1D and CD are associated with DRB4*01:03:01, DRB3*01:01:02, and DRB3*02:02:01 of which DRB4*01:03:01 confers the strongest risk allele for developing T1D w/CD.

Identification of Isopeptides Between Human Tissue Transglutaminase and Wheat, Rye, and Barley Gluten Peptides

Celiac disease (CD) is a chronic immune-mediated enteropathy of the small intestine, which is triggered by the ingestion of storage proteins (gluten) from wheat, rye, and barley in genetically predisposed individuals. Human tissue transglutaminase (TG2) plays a central role in the pathogenesis of CD, because it is responsible for specific gluten peptide deamidation and covalent crosslinking, resulting in the formation of N^ε-(γ-glutamyl)-lysine isopeptide bonds. The resulting TG2-gluten peptide complexes are assumed to cause the secretion of anti-TG2 autoantibodies, but the underlying mechanisms are only partly known. To gain more insight into the structures of these complexes, the aim of our study was to identify TG2-gluten isopeptides. With the use of discovery-driven as well as targeted nanoscale liquid chromatography tandem mass spectrometry, we detected 29 TG2-gluten isopeptides in total, involving seven selected TG2 lysine residues (K205, K265, K429, K468, K590, K600, K677). Several gluten peptides carried known B-cell epitopes and/or T-cell epitopes, either intact 9-mer core regions or partial sequences, as well as sequences bearing striking similarities to already known epitopes. These novel insights into the molecular structures of TG2-gluten peptide complexes may help clarify their physiological relevance in the initiation of CD autoimmunity and the role of anti-TG2 autoantibodies.

Nonceliac Gluten Sensitivity—A Masquerading IBS or a Real Phenomenon?

The gluten-free diet has become popular among the public. People who are using this diet have reported symptom relief once gluten has been removed from their diet. Nonceliac gluten sensitivity (NCGS) has emerged as a new diagnosis for those patients who have tested negative for celiac disease. Although there are no diagnostic markers established for NCGS, its symptomatology ranges from gastrointestinal symptoms to neuropsychiatric symptoms. Indeed, some of these symptoms are also seen in patients with irritable bowel syndrome (IBS), such as abdominal pain, bloating, altered bowel movement, diarrhea, and constipation. It is important to add that unlike celiac disease, NGCS has never been associated with any long-term malignancy. We aim to review the recent clinical data available on this topic and address the overlap symptoms between NCGS and IBS. We concluded that despite the overlap symptoms between both diseases, NCGS is a real clinical phenomenon that awaits its own diagnostic clinical criteria and specific laboratory markers. We suggest that patients with gluten sensitivity who are negative for celiac disease should be considered for NCGS.

HLA-DQ Genotyping, Duodenal Histology, and Response to Exclusion Diet in Autistic Children With Gastrointestinal Symptoms

OBJECTIVES

A correlation between autism spectrum disorders (ASDs) and gastrointestinal (GI) problems, and a possible link between gluten consumption and ASD have been increasingly reported. Gluten/casein-free diet (GCFD) is often undertaken, with conflicting results. This study aimed at evaluating the distribution of human leukocyte antigen (HLA)-DQ2/DQ8 typing among patients with ASD with GI symptoms, together with its correlation with duodenal histology and response to GCFD.

METHODS

Between 2002 and 2015 all patients with ASD with GI symptoms referred to our outpatient clinic, displaying clinical, laboratory, or ultrasound findings suggestive of organic disease, underwent endoscopy, celiac disease (CD) serum antibodies testing and HLA-DQ2/DQ8 genotyping. Patients were prescribed a 6-month GCFD, and then clinically reassessed.

RESULTS

Among 151 enrolled patients, 134 (89%) were negative for CD-specific antibodies; 72 (48%) were positive for HLA-DQ2/DQ8; and 56 (37%) showed duodenal microscopic inflammation. Clinical improvement was observed in non-CD patients irrespective of the rigorous or partial adherence to the diet, being the difference nonstatistically significant. Response to diet was related to the presence of histological duodenal alterations at baseline (odds ratio 11.323, 95% confidence interval 1.386-92.549 for Marsh 2 pattern), but not to HLA-DQ2/DQ8 positivity (odds ratio 1.120, 95% confidence interval 0.462-2.716).

CONCLUSIONS

Our data suggest that children with ASD with GI symptoms have a high prevalence of duodenal intraepithelial lymphocytic infiltration, which seems to be linked to a mechanism other than autoimmune response to gluten consumption. Alteration of duodenal histology, but not the HLA-DQ2/DQ8 status, was associated with clinical response to the diet.

Lactobacilli Degrade Wheat Amylase Trypsin Inhibitors to Reduce Intestinal Dysfunction Induced by Immunogenic Wheat Proteins

BACKGROUND & AIMS

Wheat-related disorders, a spectrum of conditions induced by the ingestion of gluten-containing cereals, have been increasing in prevalence. Patients with celiac disease have gluten-specific immune responses, but the contribution of non-gluten proteins to symptoms in patients with celiac disease or other wheat-related disorders is controversial.

METHODS

C57BL/6 (control), Myd88^-/-, Ticam1^-/-, and Il15^-/- mice were placed on diets that lacked wheat or gluten, with or without wheat amylase trypsin inhibitors (ATIs), for 1 week. Small intestine tissues were collected and intestinal intraepithelial lymphocytes (IELs) were measured; we also investigated gut permeability and intestinal transit. Control mice fed ATIs for 1 week were gavaged daily with Lactobacillus strains that had high or low ATI-degrading capacity. Nonobese diabetic/DQ8 mice were sensitized to gluten and fed an ATI diet, a gluten-containing diet or a diet with ATIs and gluten for 2 weeks. Mice were also treated with Lactobacillus strains that had high or low ATI-degrading capacity. Intestinal tissues were collected and IELs, gene expression, gut permeability and intestinal microbiota profiles were measured.

RESULTS

In intestinal tissues from control mice, ATIs induced an innate immune response by activation of Toll-like receptor 4 signaling to MD2 and CD14, and caused barrier dysfunction in the absence of mucosal damage. Administration of ATIs to gluten-sensitized mice expressing HLA-DQ8 increased intestinal inflammation in response to gluten in the diet. We found ATIs to be degraded by Lactobacillus, which reduced the inflammatory effects of ATIs.

CONCLUSIONS

ATIs mediate wheat-induced intestinal dysfunction in wild-type mice and exacerbate inflammation to gluten in susceptible mice. Microbiome-modulating strategies, such as administration of bacteria with ATI-degrading capacity, may be effective in patients with wheat-sensitive disorders.

Soluble Syndecan-1: A Novel Biomarker of Small Bowel Mucosal Damage in Children with Celiac Disease

BACKGROUND

Syndecan-1 (SDC1) is essential for maintaining normal epithelial barrier. Shedding of SDC1 ectodomain, reflected by serum soluble syndecan-1 (SSDC1) levels, is regulated by inflammation. Increased intestinal permeability plays a central role in celiac disease (CD). The association between SSDC1 levels and mucosal damage in CD has not been evaluated.

AIMS

To evaluate serum SSDC1 levels in children with CD and to determine its relationship with histological grading classified by modified Marsh criteria.

METHODS

This is a cross-sectional, pilot study, in which serum SSDC1 was analyzed by ELISA in a cohort of 49 untreated children with CD and 15 children with nonspecific abdominal pain (AP). CD was diagnosed based on positive celiac serology and small intestinal biopsy. SSDC1 levels at the time of biopsy were correlated with Marsh grading. Controls were defined by AP, negative celiac serology, normal upper endoscopy, and small intestinal biopsies.

RESULTS

SSDC1 levels were significantly higher in CD patients compared to AP controls (116.2 ± 161 vs. 41.3 ± 17.5 ng/ml, respectively, p < 0.01). SSDC1 levels were significantly higher in patients with Marsh 3c lesion compared to AP controls (170.6 ± 201 vs. 41.3 ± 17.5 ng/ml, respectively, p < 0.05). SSDC1 concentrations displayed a significant correlation with mucosal damage defined by Marsh (r = 0.39, p < 0.05).

CONCLUSION

This is the first study demonstrating elevated levels of serum SSDC1 in children with CD. Our results suggest that SSDC1 is a potentially novel marker of intestinal mucosal damage in patients with CD. Its applicability as a surrogate biomarker in CD remains to be determined.

Gliadin-Specific CD8+ T Cell Responses Restricted by HLA Class I A*0101 and B*0801 Molecules in Celiac Disease Patients

Initial studies associated the HLA class I A*01 and B*08 alleles with celiac disease (CD) susceptibility. Subsequent analyses showed a primary association with HLA class II alleles encoding for the HLA DQ2.5 molecule. Because of the strong linkage disequilibrium of A*01 and B*08 alleles with the DR3-DQ2.5 haplotype and a recent genome-wide association study indicating that B*08 and B*39 are predisposing genes, the etiologic role of HLA class I in CD pathogenesis needs to be addressed. We screened gliadin proteins (2α-, 2ω-, and 2γ-gliadin) using bioinformatic algorithms for the presence of peptides predicted to bind A*0101 and B*0801 molecules. The top 1% scoring 9- and 10-mer peptides (N = 97, total) were synthesized and tested in binding assays using purified A*0101 and B*0801 molecules. Twenty of ninety-seven peptides bound B*0801 and only 3 of 97 bound A*0101 with high affinity (IC₅₀ < 500 nM). These 23 gliadin peptides were next assayed by IFN-γ ELISPOT for recognition in peripheral blood cells of CD patients and healthy controls carrying the A*0101 and/or B*0801 genes and in A*0101/B*0801^- CD patients. Ten of the twenty-three peptides assayed recalled IFN-γ responses mediated by CD8⁺ T cells in A*0101/B*0801⁺ patients with CD. Two peptides were restricted by A*0101, and eight were restricted by B*0801. Of note, 50% (5/10) of CD8⁺ T cell epitopes mapped within the γ-gliadins. Our results highlight the value of predicted binding to HLA molecules for identifying gliadin epitopes and demonstrate that HLA class I molecules restrict the anti-gluten T cell response in CD patients.

Immune Toxicities Elicted by CTLA-4 Blockade in Cancer Patients Are Associated with Early Diversification of the T-cell Repertoire

While immune checkpoint blockade elicits efficacious responses in many patients with cancer, it also produces a diverse and unpredictable number of immune-related adverse events (IRAE). Mechanisms driving IRAEs are generally unknown. Because CTLA-4 blockade leads to proliferation of circulating T cells, we examined in this study whether ipilimumab treatment leads to clonal expansion of tissue-reactive T cells. Rather than narrowing the T-cell repertoire to a limited number of clones, ipilimumab induced greater diversification in the T-cell repertoire in IRAE patients compared with patients without IRAEs. Specifically, ipilimumab triggered increases in the numbers of clonotypes, including newly detected clones and a decline in overall T-cell clonality. Initial broadening in the repertoire occurred within 2 weeks of treatment, preceding IRAE onset. IRAE patients exhibited greater diversity of CD4⁺ and CD8⁺ T cells, but showed no differences in regulatory T-cell numbers relative to patients without IRAEs. Prostate-specific antigen responses to ipilimumab were also associated with increased T-cell diversity. Our results show how rapid diversification in the immune repertoire immediately after checkpoint blockade can be both detrimental and beneficial for patients with cancer. Cancer Res; 77(6); 1322-30. ©2016 AACR.

The opioid effects of gluten exorphins: asymptomatic celiac disease

Gluten-containing cereals are a main food staple present in the daily human diet, including wheat, barley, and rye. Gluten intake is associated with the development of celiac disease (CD) and related disorders such as diabetes mellitus type I, depression, and schizophrenia. However, until now, there is no consent about the possible deleterious effects of gluten intake because of often failing symptoms even in persons with proven CD. Asymptomatic CD (ACD) is present in the majority of affected patients and is characterized by the absence of classical gluten-intolerance signs, such as diarrhea, bloating, and abdominal pain. Nevertheless, these individuals very often develop diseases that can be related with gluten intake. Gluten can be degraded into several morphine-like substances, named gluten exorphins. These compounds have proven opioid effects and could mask the deleterious effects of gluten protein on gastrointestinal lining and function. Here we describe a putative mechanism, explaining how gluten could "mask" its own toxicity by exorphins that are produced through gluten protein digestion.

The genetics of human autoimmune disease: A perspective on progress in the field and future directions

Progress in defining the genetics of autoimmune disease has been dramatically enhanced by large scale genetic studies. Genome-wide approaches, examining hundreds or for some diseases thousands of cases and controls, have been implemented using high throughput genotyping and appropriate algorithms to provide a wealth of data over the last decade. These studies have identified hundreds of non-HLA loci as well as further defining HLA variations that predispose to different autoimmune diseases. These studies to identify genetic risk loci are also complemented by progress in gene expression studies including definition of expression quantitative trait loci (eQTL), various alterations in chromatin structure including histone marks, DNase I sensitivity, repressed chromatin regions as well as transcript factor binding sites. Integration of this information can partially explain why particular variations can alter proclivity to autoimmune phenotypes. Despite our incomplete knowledge base with only partial definition of hereditary factors and possible functional connections, this progress has and will continue to facilitate a better understanding of critical pathways and critical changes in immunoregulation. Advances in defining and understanding functional variants potentially can lead to both novel therapeutics and personalized medicine in which therapeutic approaches are chosen based on particular molecular phenotypes and genomic alterations.

Increased arterial stiffness and its relationship with inflammation, insulin, and insulin resistance in celiac disease

OBJECTIVE

Celiac disease (CD) is a lifelong, chronic, immune-mediated, inflammatory small bowel disorder, precipitated by exposure to dietary gluten and related proteins in genetically predisposed individuals. Recent studies have shed new light on the importance of inflammation in the pathogenesis of arterial stiffness. The aim of this study was to evaluate arterial stiffness using pulse wave velocity (PWV) in adult CD patients without cardiovascular risk factors in comparison with a control group.

PATIENTS AND METHODS

A total of 58 patients with CD without cardiovascular risk factors and age-matched and sex-matched healthy controls were enrolled in the study. All patients completed a standard questionnaire form, and various laboratory parameters were assessed. Vascular measurements, including PWV, were carried out using a Mobil-O-Graph 24-h pulse wave analysis monitor, an automatic oscillometric device.

RESULTS

Although cardiovascular risk factors, such as low-density lipoprotein cholesterol and triglyceride, were significantly lower (P<0.05) in celiac patients than in controls, the erythrocyte sedimentation rate, C-reactive protein, insulin, homeostasis model assessment of insulin resistance, homocysteine, and 24 h, day, and night PWV values were higher in patients with CD than in controls (P<0.05). A multiple linear regression analysis showed that PWV was correlated positively with age and the duration of CD.

CONCLUSION

This study found increased arterial stiffness, homocysteine, erythrocyte sedimentation rate, C-reactive protein, insulin, and homeostasis model assessment of insulin resistance in patients with CD and provides evidence for the potential contribution of these parameters and inflammation toward arterial stiffening, independent of conventional cardiovascular risk factors.

Contrasting the Genetic Background of Type 1 Diabetes and Celiac Disease Autoimmunity

Type 1 diabetes (T1D) and celiac disease (CeD) cluster in families and can occur in the same individual. Genetic loci have been associated with susceptibility to both diseases. Our aim was to explore the genetic differences between individuals developing both these diseases (double autoimmunity) versus those with only one. We hypothesized that double autoimmunity individuals carry more of the genetic risk markers that are shared between the two diseases independently. SNPs were genotyped in loci associated with T1D (n=42) and CeD (n=28) in 543 subjects who developed double autoimmunity, 2,472 subjects with T1D only, and 2,223 CeD-only subjects. For identification of loci that were specifically associated with individuals developing double autoimmunity, two association analyses were conducted: double autoimmunity versus T1D and double autoimmunity versus CeD. HLA risk haplotypes were compared between the two groups. The CTLA4 and IL2RA loci were more strongly associated with double autoimmunity than with either T1D or CeD alone. HLA analyses indicated that the T1D high-risk genotype, DQ2.5/DQ8, provided the highest risk for developing double autoimmunity (odds ratio 5.22, P=2.25×10(-29)). We identified a strong HLA risk genotype (DQ2.5/DQ8) predisposing to double autoimmunity, suggesting a dominant role for HLA. Non-HLA loci, CTLA4 and IL2RA, may also confer risk to double autoimmunity. Thus, CeD patients who carry the DQ2.5/DQ8 genotype may benefit from periodic screening of autoantibodies related to T1D.

Food allergy in irritable bowel syndrome: The case of non-celiac wheat sensitivity

Irritable bowel syndrome (IBS) is one of the most common gastrointestinal disorders, having a prevalence of 12%-30% in the general population. Most patients with IBS attribute their symptoms to adverse food reactions. We review the role of diet in the pathogenesis of IBS and the importance of dietary factors in the management of these patients. The MEDLINE electronic database (1966 to Jan 2015) was searched using the following keywords: "food", "diet", "food allergy", "food hypersensitivity", "food intolerance", "IBS", "epidemiology", "pathogenesis", "pathophysiology", "diagnosis", "treatment". We found 153 eligible papers; 80 were excluded because: not written in English, exclusive biochemical and experimental research, case reports, reviews, and research otherwise not relevant to our specific interest. We selected 73 papers: 43 original papers, 26 reviews and 4 letters to the editor. These papers focused on IBS pathogenesis, the association between IBS and atopy, and between IBS and food allergy, the relationship between IBS and non-celiac wheat sensitivity, the role of diet in IBS. Pending further scientific evidence, a cautious approach is advisable but the concept of food allergy should be included as a possible cause of IBS, and a dietary approach may have a place in the routine clinical management of IBS.

Discriminant score for celiac disease based on immunohistochemical analysis of duodenal biopsies

OBJECTIVES

Celiac disease (CD) represents a spectrum, which includes cases with minor histological abnormalities (potential CD). The aim of this work is to evaluate the contribution of immunohistochemical analysis of duodenal biopsies to the diagnosis of gluten-related minor enteropathy.

METHODS

Duodenal biopsies from 56 patients with untreated CD and 56 controls were analyzed for CD3 and γδ intraepithelial lymphocyte number, γδ/CD3 ratio, and density of CD25+ lamina propria cells. A discriminant equation was obtained by which 61 more biopsies with normal villous architecture were blindly evaluated.

RESULTS

All of the immunohistochemical parameters were significantly different between patients with CD and controls. None of the single parameters showed sufficient specificity for CD. The combination of all of the 4 markers resulted in the following discriminant equation: discriminant score (Dscore) = (CD3 × 0.06) - (γδ × 0.119) + (CD25 × 0.012) + (γδ/CD3 × 0.131) - 4.709. Using this Dscore, patients were correctly classified as celiac or controls in 97.3% of the cases. When this equation was applied to a validation set of 61 patients with normal villous architecture and unknown diagnosis, 92.9% of those with a positive score turned out to be patients with potential CD. A normal score, however, did not exclude this condition.

CONCLUSIONS

Immunohistochemistry represents a specific tool for the diagnosis of CD, but does lack sensitivity in detecting all of the potential CD cases.

Assessing of Celiac Disease and Nonceliac Gluten Sensitivity

The publication of papers on the topic of gluten related disorders has substantially increased over the last few years. This has motivated healthcare professionals to pay attention not only to celiac disease and wheat allergy but also to a condition termed nonceliac gluten sensitivity (NCGS). Until now this condition has been diagnosed clinically on the basis of exclusion criteria and clinical response to gluten withdrawal. In addition, recent research in this field has shown that other food components distinct from gluten are implicated in NCGS cases, thereby changing our general understanding of NCGS diagnosis in either individuals on gluten containing diets or those already following a gluten-free diet with no proper diagnostic work-up of celiac disease. With this in mind, the assessment of NCGS will require extensive knowledge of celiac disease manifestations and the laboratory tests commonly performed during diagnosis of celiac disease.

Vitamin D levels and cytokine profiles in patients with systemic lupus erythematosus

OBJECTIVES

To evaluate the expression of Th1, Th2, and Th17 cytokines in patients with systemic lupus erythematosus (SLE), and verify the association between serum cytokine levels and vitamin D concentration.

METHODS

The sample consisted of 172 patients with SLE. 25-Hydroxyvitamin D (25(OH)D) levels were measured by chemiluminescence and 25(OH)D levels <20 ng/mL were considered to reflect vitamin D deficiency. Serum cytokine levels were measured in once-thawed samples, using a Th1/Th2/Th17 CBA (cytometric beads array) kit.

RESULTS

One hundred and sixty-one (93.6%) patients were women and 128 (74.4%) were of European descent. Mean patient age was 40.5 ± 13.8 years, and mean age at diagnosis was 31.5 ± 13.4 years. At the time of study entry, patients had a median (IQR) SLEDAI of 2 (1-4) and SLICC of 0 (0-1). Mean 25(OH)D concentration was 25.4 ± 11.04 ng/mL. Fifty-nine (34.3%) patients had a vitamin D deficiency. No statistically significant associations were identified between cytokine and vitamin D levels. The most significant finding was a positive correlation between INF-α levels and SLEDAI (r(s) = 0.22, p = 0.04).

CONCLUSION

Although vitamin D deficiencies are highly prevalent in patients with SLE, vitamin D levels were not significantly associated with patient cytokine profiles. The positive correlation between IFN-α levels and SLEDAI showed in this study corroborates other findings in the literature. The present results did not replicate those of in vitro studies of the effect of vitamin D levels on cytokine profiles. Placebo-controlled intervention trials of the effect of vitamin D on cytokine profiles are still required before any definitive conclusions can be drawn regarding the association between these variables.

Interleukin-15, a master piece in the immunological jigsaw of celiac disease

BACKGROUND

The immune response causing celiac disease (CD) depends on the activation of intestinal CD4+ T cells by gluten-derived peptides presented by HLA-DQ2 or HLA-DQ8 molecules, the main genetic risk factor. However, additional factors are necessary to impair immune tolerance to dietary gluten, to stimulate intraepithelial lymphocytes (IEL) and to induce intestinal damage.

KEY MESSAGES

Current data point to a central role of interleukin-15 (IL-15). In situ and ex vivo studies indicate that IL-15 stimulates the accumulation and cytotoxic activation of CD8+ T IEL in active CD, and that of the malignant innate-like IEL in type II refractory CD (RCDII). Other studies show that IL-15 impairs the immunoregulatory control of effector T cells, notably CD8+. Recently, animal models have been designed to investigate the respective role of CD4+ T cells and IL-15 in CD. We discuss more particularly our results in such a model, which shows that IL-15 produced in excess in the intestine can cooperate with CD4+ T cells specific for a dietary antigen to trigger a celiac-like enteropathy. In this mouse model, CD4+ T cells activated by dietary ovalbumin secreted IL-2 which, along with IL-15, stimulated the expansion of noncognate intestinal cytotoxic CD8+ T cells containing large amounts of granzyme B. In the presence of IL-15, the latter cells did not respond to regulatory T cells, and accumulated in the intestine close to epithelial damage.

CONCLUSION

On the basis of these data, we propose that, in CD, gluten-specific CD4+ T cells synthesize cytokines that synergize with IL-15 to license the expansion and activation of cytotoxic IEL, which drive tissue damage. We suggest that IL-15 is a meaningful therapeutic target, notably in patients with RCDII in which malignant IEL can respond to IL-15 independently of signals provided by CD4+ T cells.

Sourdough fermentation of wheat flour does not prevent the interaction of transglutaminase 2 with α2-gliadin or gluten

The enzyme transglutaminase 2 (TG2) plays a crucial role in the initiation of celiac disease by catalyzing the deamidation of gluten peptides. In susceptible individuals, the deamidated peptides initiate an immune response leading to celiac disease. Several studies have addressed lactic fermentation plus addition of enzymes as a means to degrade gluten in order to prevent adverse response in celiacs. Processing for complete gluten degradation is often harsh and is not likely to yield products that are of comparable characteristics as their gluten-containing counterparts. We are concerned that incomplete degradation of gluten may have adverse effects because it leads to more available TG2-binding sites on gluten peptides. Therefore, we have investigated how lactic acid fermentation affects the potential binding of TG2 to gluten protein in wheat flour by means of estimating TG2-mediated transamidation in addition to measuring the available TG2-binding motif QLP, in α₂-gliadin. We show that lactic fermentation of wheat flour, as slurry or as part of sourdough bread, did not decrease the TG2-mediated transamidation, in the presence of a primary amine, to an efficient level (73%–102% of unfermented flour). Nor did the lactic fermentation decrease the available TG2 binding motif QLP in α₂-gliadin to a sufficient extent in sourdough bread (73%–122% of unfermented control) to be useful for celiac safe food.

Weaknesses of histological analysis in celiac disease diagnosis: new possible scenarios

INTRODUCTION

Celiac disease (CD) is an autoimmune disorder triggered by the ingestion of gluten. Serology and organ culture system can support CD diagnosis, despite histology being the gold standard.

AIM

We wanted to test the uniformity of application of Marsh-Oberhuber criteria by five different histologists. We also compared histological and serological data with cultural results to consider new possible strategies in CD diagnosis.

METHODS

We studied 114 patients, who were divided in two groups. Group A was composed of 66 patients on a gluten-containing diet, with gluten-related signs and symptoms, showing positive serological anti-endomysial antibodies (EMA) and anti-tissue transglutaminase (anti- tTG). Group B was composed of 48 disease-control patients, presenting serological EMA and anti-tTG negative results. All patients studied underwent esophagogastroduodenoscopy with duodenal biopsy and duodenal mucosa organ culture. All histological samples were evaluated by five different histologists according to an appropriate questionnaire following Marsh-Oberhuber classification. Cohen κ inter-test was used for evaluating the agreement between histologists regarding group A.

RESULTS

Strength of agreement was fair/moderate for villous:crypt ratio, moderate/good for villous height and crypt depth, and poor for intraepithelial lymphocytosis. Patients belonging to group A presented positive serological as well as cultural results in 100% of cases. None of the patients belonging to group B presented serological or cultural positive results.

DISCUSSION

Our study stresses the limits of histological interpretation due to the lack of uniformity in the use of Marsh-Oberhuber classification. These findings could cast doubt on the role of histology as CD gold standard and could open a debate on the most appropriate CD diagnostic procedure.

Non-celiac gluten sensitivity: literature review

BACKGROUND

A significant percentage of the general population report problems caused by wheat and/or gluten ingestion, even though they do not have celiac disease (CD) or wheat allergy (WA), because they test negative both for CD-specific serology and histopathology and for immunoglobulin E (IgE)-mediated assays. Most patients report both gastrointestinal and nongastrointestinal symptoms, and all report improvement of symptoms on a gluten-free diet. This clinical condition has been named non-celiac gluten sensitivity (NCGS).

AIM

We attempt to define the current pathogenic, clinical, and diagnostic criteria of this "new" disease, to provide a practical view that might be useful to evaluate, diagnose, and manage NCGS patients.

METHODS

We reviewed the international literature through PubMed and Medline, using the search terms "wheat (hyper)sensitivity," "wheat allergy," "wheat intolerance," "gluten (hyper)sensitivity," and "gluten intolerance," and we discuss current knowledge about NCGS.

RESULTS

It has been demonstrated that patients suffering from NCGS are a heterogeneous group, composed of several subgroups, each characterized by different pathogenesis, clinical history, and, probably, clinical course. NCGS diagnosis can be reached only by excluding CD and WA. Recent evidence shows that a personal history of food allergy in infancy, coexistent atopy, positive for immunoglobulin G (IgG) antigliadin antibodies and flow cytometric basophil activation test, with wheat and duodenal and/or ileum-colon intraepithelial and lamina propria eosinophil counts, could be useful to identify NCGS patients.

CONCLUSIONS

Future research should aim to identify reliable biomarkers for NCGS diagnosis and to better define the different NCGS subgroups. Key teaching points: • Most patients report both gastrointestinal and nongastrointestinal symptoms, and all agree that there is an improvement of symptoms on a gluten-free diet. • NCGS diagnosis can be reached only by excluding celiac disease and wheat allergy. • Patients suffering from NCGS are a heterogeneous group, composed of several subgroups, each characterized by different pathogenesis, clinical history, and, probably, clinical course. • A personal history of food allergy in infancy, coexistent atopy, positive IgG antigliadin antibodies (AGA) and flow cytometric basophil activation test, with wheat and duodenal and/or ileum-colon intraepithelial and lamina propria eosinophil counts, could be useful to identify NCGS patients. • Future research should aim to identify reliable biomarkers for NCGS diagnosis and to better define the different NCGS subgroup.

Experimental hookworm infection and gluten microchallenge promote tolerance in celiac disease

BACKGROUND

Celiac disease (CeD) is a common gluten-sensitive autoimmune enteropathy. A gluten-free diet is an effective treatment, but compliance is demanding; hence, new treatment strategies for CeD are required.

OBJECTIVE

Parasitic helminths hold promise for treating inflammatory disorders, so we examined the influence of experimental hookworm infection on the predicted outcomes of escalating gluten challenges in CeD subjects.

METHODS

A 52-week study was conducted involving 12 adults with diet-managed CeD. Subjects were inoculated with 20 Necator americanus larvae, and escalating gluten challenges consumed as pasta were subsequently administered: (1) 10 to 50 mg for 12 weeks (microchallenge); (2) 25 mg daily + 1 g twice weekly for 12 weeks (GC-1g); and (3) 3 g daily (60-75 straws of spaghetti) for 2 weeks (GC-3g). Symptomatic, serologic, and histological outcomes evaluated gluten toxicity. Regulatory and inflammatory T cell populations in blood and mucosa were examined.

RESULTS

Two gluten-intolerant subjects were withdrawn after microchallenge. Ten completed GC-1g, 8 of whom enrolled in and completed GC-3g.

PRIMARY OUTCOMES

median villous height-to-crypt depth ratios (2.60-2.63; P = .98) did not decrease as predicted after GC-1g, and the mean IgA-tissue transglutaminase titers declined, contrary to the predicted rise after GC-3g.

SECONDARY OUTCOMES

quality of life scores improved (46.3-40.6; P = .05); celiac symptom indices (24.3-24.3; P = .53), intra-epithelial lymphocyte percentages (32.5-35.0; P = .47), and Marsh scores were unchanged by gluten challenge. Intestinal T cells expressing IFNγ were reduced following hookworm infection (23.9%-11.5%; P = .04), with corresponding increases in CD4(+) Foxp3(+) regulatory T cells (0.19%-1.12%; P = .001).

CONCLUSIONS

Necator americanus and gluten microchallenge promoted tolerance and stabilized or improved all tested indices of gluten toxicity in CeD subjects.

Matrix expansion and syncytial aggregation of syndecan-1+ cells underpin villous atrophy in coeliac disease

Background

We studied the expression of sulphated glycosaminoglycans (GAGs) in coeliac disease (CD) mucosa, as they are critical determinants of tissue volume, which increases in active disease. We also examined mucosal expression of IL-6, which stimulates excess GAG synthesis in disorders such as Grave's ophthalmopathy.

Methods

We stained archival jejunal biopsies from 5 children with CD at diagnosis, on gluten-free diet and challenge for sulphated GAGs. We then examined duodenal biopsies from 9 children with CD compared to 9 histological normal controls, staining for sulphated GAGs, heparan sulphate proteoglycans (HSPG), short-chain HSPG (Δ-HSPG) and the proteoglycan syndecan-1 (CD138), which is expressed on epithelium and plasma cells. We confirmed findings with a second monoclonal in another 12 coeliac children. We determined mucosal IL-6 expression by immunohistochemistry and PCR in 9 further cases and controls, and used quantitative real time PCR for other Th17 pathway cytokines in an additional 10 cases and controls.

Results

In CD, HSPG expression was lost in the epithelial compartment but contrastingly maintained within an expanded lamina propria. Within the upper lamina propria, clusters of syndecan-1+ plasma cells formed extensive syncytial sheets, comprising adherent plasma cells, lysed cells with punctate cytoplasmic staining and shed syndecan ectodomains. A dense infiltrate of IL-6⁺ mononuclear cells was detected in active coeliac disease, also localised to the upper lamina propria, with significantly increased mRNA expression of IL-6 and IL-17A but not IL-23 p19.

Conclusions

Matrix expansion, through syndecan-1+ cell recruitment and lamina propria GAG increase, underpins villous atrophy in coeliac disease. The syndecan-1+ cell syncytia and excess GAG production recapitulate elements of the invertebrate encapsulation reaction, itself dependent on insect transglutaminase and glutaminated early response proteins. As in other matrix expansion disorders, IL-6 is upregulated and represents a logical target for immunotherapy in patients with coeliac disease refractory to gluten-free diet.

Long term follow up of celiac disease-is atherosclerosis a problem?

Celiac disease (CD) is a lifelong condition and it often involves impaired nutrition, wide spectrum of symptoms and it requires constant dietetic treatment. The impact of the gluten-free diet on patients’ nutritional status and on the other biochemical parameters is being widely investigated. In this article we looked into particular risk factors that might lead to increased prevalence of atherosclerosis in CD patients, including nutritional status, gluten-free diet, lipids profile and concomitant disease—type 1 diabetes mellitus. Here, we present the current data and research on these risk factors of atherosclerosis with respect to celiac disease.

Testing safety of germinated rye sourdough in a celiac disease model based on the adoptive transfer of prolamin-primed memory T cells into lymphopenic mice

The current treatment for celiac disease is strict gluten-free diet. Technical processing may render gluten-containing foods safe for consumption by celiac patients, but so far in vivo safety testing can only be performed on patients. We modified a celiac disease mouse model to test antigenicity and inflammatory effects of germinated rye sourdough, a food product characterized by extensive prolamin hydrolysis. Lymphopenic Rag1-/- or nude mice were injected with splenic CD4+CD62L-CD44high-memory T cells from gliadin- or secalin-immunized wild-type donor mice. We found that: 1) Rag1-/- recipients challenged with wheat or rye gluten lost more body weight and developed more severe histological duodenitis than mice on gluten-free diet. This correlated with increased secretion of IFNγ, IL-2, and IL-17 by secalin-restimulated splenocytes. 2) In vitro gluten testing using competitive R5 ELISA demonstrated extensive degradation of the gluten R5 epitope in germinated rye sourdough. 3) However, in nude recipients challenged with germinated rye sourdough (vs. native rye sourdough), serum anti-secalin IgG/CD4+ T helper 1-associated IgG2c titers were only reduced, but not eliminated. In addition, there were no reductions in body weight loss, histological duodenitis, or T cell cytokine secretion in Rag1-/- recipients challenged accordingly.

IN CONCLUSION

1) prolamin-primed CD4+CD62L-CD44high-memory T cells induce gluten-sensitive enteropathy in Rag1-/- mice. 2) Hydrolysis of secalins in germinated rye sourdough remains incomplete. Secalin peptides retain B and T cell stimulatory capacity and remain harmful to the intestinal mucosa in this celiac disease model. 3) Current antibody-based prolamin detection methods may fail to detect antigenic gluten fragments in processed cereal food products.

Role of CXCR3/CXCL10 axis in immune cell recruitment into the small intestine in celiac disease

Lymphocytic infiltration in the lamina propria (LP), which is primarily composed of CD4⁺ Th1 cells and plasma cells, and increased numbers of intraepithelial lymphocytes (IELs), is a characteristic finding in active celiac disease (CD). Signals for this selective cell recruitment have not been fully established. CXCR3 and its ligands, particularly CXCL10, have been suggested to be one of the most relevant pathways in the attraction of cells into inflamed tissues. In addition, CXCR3 is characteristically expressed by Th1 cells. The aim of this work was to investigate the participation of the chemokine CXCL10/CXCR3 axis in CD pathogenesis. A higher concentration of CXCL10 was found in the serum of untreated CD patients. The mRNA levels of CXCL10 and CXCL11 but not CXCL9 were significantly higher in duodenal biopsies from untreated CD patients compared with non-CD controls or treated patients. The results demonstrate that CXCL10 is abundantly produced in untreated CD and reduced in treated patients, and the expression of CXCL10 was found to be correlated with the IFNγ levels in the tissue. Plasma cells and enterocytes were identified as CXCL10-producing cells. Moreover, the CXCL10 expression in intestinal tissues was upregulated by poly I:C and IL-15. IELs, LP T lymphocytes, and plasma cells, which infiltrate the intestinal mucosa in untreated CD, express CXCR3. The CXCR3/CXCL10 signalling axis is overactivated in the small intestinal mucosa in untreated patients, and this finding explains the specific recruitment of the major cell populations that infiltrate the epithelium and the LP in CD.

Lactase persistence and augmented salivary alpha-amylase gene copy numbers might have been selected by the combined toxic effects of gluten and (food born) pathogens

Various positively selected adaptations to new nutrients have been identified. Lactase persistence is among the best known, conferring the ability for drinking milk at post weaning age. An augmented number of amylase gene (AMY1) copies, giving rise to higher salivary amylase activity, has been implicated in the consumption of starch-rich foods. Higher AMY1 copy numbers have been demonstrated in populations with recent histories of starchy-rich diets. It is however questionable whether the resulting polymorphisms have exerted positive selection only by providing easily available sources of macro and micronutrients. Humans have explored new environments more than any other animal. Novel environments challenge the host, but especially its immune system with new climatic conditions, food and especially pathogens. With the advent of the agricultural revolution and the concurrent domestication of cattle came new pathogens. We contend that specific new food ingredients (e.g., gluten) and novel pathogens drove selection for lactase persistence and higher AMY gene copy numbers. Both adaptations provide ample glucose for activating the sodium glucose-dependent co-transporter 1 (SGLT1), which is the principal glucose, sodium and water transporter in the gastro-intestinal tract. Their rapid uptake confers protection against potentially lethal dehydration, hyponatremia and ultimately multiple organ failure. Oral rehydration therapy aims at SGLT1 activity and is the current treatment of choice for chronic diarrhoea and vomiting. We hypothesize that lifelong lactase activity and rapid starch digestion should be looked at as the evolutionary covalent of oral rehydration therapy.

Detection of specific IgA antibodies against a novel deamidated 8-Mer gliadin peptide in blood plasma samples from celiac patients

We studied whether celiac disease (CD) patients produce antibodies against a novel gliadin peptide specifically generated in the duodenum of CD patients by a previously described pattern of CD-specific duodenal proteases. Fingerprinting and ion-trap mass spectrometry of CD-specific duodenal gliadin-degrading protease pattern revealed a new 8-mer gliadin-derived peptide. An ELISA against synthetic deamidated 8-mer peptides (DGP 8-mer) was used to study the presence of IgA anti-DGP 8-mer antibodies in plasma samples from 81 children (31 active CD patients (aCD), 17 CD patients on a gluten-free diet (GFD), 10 healthy controls (C) and 23 patients with other gastrointestinal pathology (GP)) and 101 adults (16 aCD, 12 GFD, 27 C and 46 GP-patients). Deamidation of the 8-mer peptide significantly increased the reactivity of the IgA antibodies from CD patients against the peptide. Significant IgA anti-DGP 8-mer antibodies levels were detected in 93.5% of aCD-, 11.8% of GFD- and 4.3% of GP-patients in children. In adults, antibodies were detected in 81.3% of aCD-patients and 8.3% of GFD-patients while were absent in 100% of C- and GP-patients. Duodenal CD-specific gliadin degrading proteases release an 8-mer gliadin peptide that once deamidated is an antigen for specific IgA antibodies in CD patients which may provide a new accurate diagnostic tool in CD.

Clinical implications of shared genetics and pathogenesis in autoimmune diseases

Many endocrine diseases, including type 1 diabetes mellitus, Graves disease, Addison disease and Hashimoto disease, originate as an autoimmune reaction that affects disease-specific target organs. These autoimmune diseases are characterized by the development of specific autoantibodies and by the presence of autoreactive T cells. They are caused by a complex genetic predisposition that is attributable to multiple genetic variants, each with a moderate-to-low effect size. Most of the genetic variants associated with a particular autoimmune endocrine disease are shared between other systemic and organ-specific autoimmune and inflammatory diseases, such as rheumatoid arthritis, coeliac disease, systemic lupus erythematosus and psoriasis. Here, we review the shared and specific genetic background of autoimmune diseases, summarize their treatment options and discuss how identifying the genetic and environmental factors that predispose patients to an autoimmune disease can help in the diagnosis and monitoring of patients, as well as the design of new treatments.

Vitamin D receptor (VDR) gene polymorphisms and susceptibility to systemic lupus erythematosus clinical manifestations

Systemic lupus erythematosus (SLE) is an autoimmune disorder with heterogeneous clinical manifestations and target tissue damage. Currently, several genes have been associated with SLE susceptibility, including vitamin D receptor (VDR), which is a mediator of immune responses through the action of vitamin D. Polymorphisms in the VDR gene can impair the vitamin D (D3) function role, and since SLE patients show deficient D3 blood levels, it leads to a possible connection to the disease's onset. In our study we searched for an association between VDR polymorphisms and risk of developing SLE, as well as the disease's clinical manifestations. We enrolled 158 SLE patients and 190 Southeast Brazilian healthy controls, genotyped for five Tag single nucleotide polymorphisms (SNPs), covering most of the VDR gene region. We found an association between VDR SNPs and SLE for the following clinical manifestations: rs11168268 and cutaneous alterations (p=0.036), rs3890733 (p=0.003) rs3890733 and arthritis (p=0.001), rs2248098 and immunological alterations (p=0.040), rs4760648 and antibody anti-dsDNA (p=0.036). No association was reported between VDR polymorphisms and SLE susceptibility.

Markers of Celiac Disease and Gluten Sensitivity in Children with Autism

OBJECTIVE

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.

METHODS

Study participants included children (with or without gastrointestinal symptoms) diagnosed with autism according to both the Autism Diagnostic Observation Schedule (ADOS) and the Autism Diagnostic Interview, Revised (ADI-R) (n = 37), their unaffected siblings (n = 27), and age-matched healthy controls (n = 76). Serum specimens were tested for antibodies to native gliadin, deamidated gliadin, and transglutaminase 2 (TG2). Affected children were genotyped for celiac disease associated HLA-DQ2 and -DQ8 alleles.

RESULTS

Children with autism had significantly higher levels of IgG antibody to gliadin compared with unrelated healthy controls (p<0.01). The IgG levels were also higher compared to the unaffected siblings, but did not reach statistical significance. The IgG anti-gliadin antibody response was significantly greater in the autistic children with gastrointestinal symptoms in comparison to those without them (p<0.01). There was no difference in IgA response to gliadin across groups. The levels of celiac disease-specific serologic markers, i.e., antibodies to deamidated gliadin and TG2, did not differ between patients and controls. An association between increased anti-gliadin antibody and presence of HLA-DQ2 and/or -DQ8 was not observed.

CONCLUSIONS

A subset of children with autism displays increased immune reactivity to gluten, the mechanism of which appears to be distinct from that in celiac disease. The increased anti-gliadin antibody response and its association with GI symptoms points to a potential mechanism involving immunologic and/or intestinal permeability abnormalities in affected children.

Transglutaminase 2-specific autoantibodies in celiac disease target clustered, N-terminal epitopes not displayed on the surface of cells

The gluten-sensitive enteropathy celiac disease is tightly associated with the production of autoantibodies specific for the enzyme transglutaminase 2 (TG2). The mechanisms underlying the activation of autoreactive B cells, however, are not well defined. To gain more insight into this autoimmune response we have characterized the binding of TG2 by a panel of human mAbs generated by expression cloning of Ig genes from single plasma cells of the celiac disease lesion. The Abs were highly specific to TG2 and bound preferentially to the open, Ca(2+)-activated enzyme conformation. Epitope mapping revealed that they recognize few distinct conformational epitopes that cluster in the N-terminal half of the enzyme. Two of the epitopes were overlapping with the fibronectin binding site in TG2, and none of the epitopes was accessible when TG2 was in a cell surface-bound form. Based on our findings, we propose that the autoantibodies are generated against the soluble, catalytically active enzyme, whereas Abs reactive with cell surface-associated TG2 are absent from the response due to negative selection of B cells recognizing membrane-bound self-Ag. The findings give insight into the mechanisms controlling the formation of anti-TG2 autoantibodies in celiac disease.

Protein kinase C delta is a substrate of tissue transglutaminase and a novel autoantigen in coeliac disease

Post-translational modification of proteins by deamidation or transamidation by tissue transglutaminase (tTG) has been suggested as a possible mechanism for the development of autoimmunity. Sequence analysis of protein kinase C delta (PKCδ) identified an amino acid motif that suggested the possibility that PKCδ was a glutamine substrate of tTG and MALDI-TOF analysis of synthesised peptides from PKCδ proved that this was the case. Polymerisation experiments using recombinant tTG and biotinylated hexapeptide substrate incorporation assays demonstrated that PKCδ is a substrate for tTG-mediated transamidation. Elevated levels of anti-PKCδ antibodies were detected in sera from patients with coeliac disease (p<0.0001) but not from patients with other autoimmune disorders. These data suggest that a subset of patients with coeliac disease produce autoantibodies against PKCδ and that this response may stem from a tTG-PKCδ substrate interaction.