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The role of HLA-DQ8 beta57 polymorphism in the anti-gluten T-cell response in coeliac disease.

ABSTRACT: Major histocompatibility complex (MHC) class II alleles HLA-DQ8 and the mouse homologue I-A(g7) lacking a canonical aspartic acid residue at position beta57 are associated with coeliac disease and type I diabetes. However, the role of this single polymorphism in disease initiation and progression remains poorly understood. The lack of Asp 57 creates a positively charged P9 pocket, which confers a preference for negatively charged peptides. Gluten lacks such peptides, but tissue transglutaminase (TG2) introduces negatively charged residues at defined positions into gluten T-cell epitopes by deamidating specific glutamine residues on the basis of their spacing to proline residues. The commonly accepted model, proposing that HLA-DQ8 simply favours binding of negatively charged peptides, does not take into account the fact that TG2 requires inflammation for activation and that T-cell responses against native gluten peptides are found, particularly in children. Here we show that beta57 polymorphism promotes the recruitment of T-cell receptors bearing a negative signature charge in the complementary determining region 3beta (CDR3beta) during the response against native gluten peptides presented by HLA-DQ8 in coeliac disease. These T cells showed a crossreactive and heteroclitic (stronger) response to deamidated gluten peptides. Furthermore, gluten peptide deamidation extended the T-cell-receptor repertoire by relieving the requirement for a charged residue in CDR3beta. Thus, the lack of a negative charge at position beta57 in MHC class II was met by negatively charged residues in the T-cell receptor or in the peptide, the combination of which might explain the role of HLA-DQ8 in amplifying the T-cell response against dietary gluten.

SUBMITTER: Hovhannisyan Z

PROVIDER: S-EPMC3784325 | biostudies-literature | 2008 Nov

REPOSITORIES: biostudies-literature

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The role of HLA-DQ8 beta57 polymorphism in the anti-gluten T-cell response in coeliac disease.

Hovhannisyan Zaruhi Z Weiss Angela A Martin Alexandra A Wiesner Martina M Tollefsen Stig S Yoshida Kenji K Ciszewski Cezary C Curran Shane A SA Murray Joseph A JA David Chella S CS Sollid Ludvig M LM Koning Frits F Teyton Luc L Jabri Bana B

Nature 20081101 7221

Major histocompatibility complex (MHC) class II alleles HLA-DQ8 and the mouse homologue I-A(g7) lacking a canonical aspartic acid residue at position beta57 are associated with coeliac disease and type I diabetes. However, the role of this single polymorphism in disease initiation and progression remains poorly understood. The lack of Asp 57 creates a positively charged P9 pocket, which confers a preference for negatively charged peptides. Gluten lacks such peptides, but tissue transglutaminase ...[more]

PMID: 19037317

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Project description:Non-coeliac gluten sensitivity (NCGS) refers to patients with primarily gastrointestinal symptoms without enteropathy that symptomatically benefit from gluten-free diet (GFD). Little is known about its pathophysiology, propensity to neurological manifestations, and if these differ from patients with coeliac disease (CD). We investigated the clinical and immunological characteristics of patients presenting with neurological manifestations with CD and those with NCGS.We compared clinical, neurophysiological, and imaging data of patients with CD and NCGS presenting with neurological dysfunction assessed and followed up regularly over a period of 20 years.Out of 700 patients, 562 were included. Exclusion criteria included no bowel biopsy to confirm CD, no HLA type available, and failure to adhere to GFD. All patients presented with neurological dysfunction and had circulating anti-gliadin antibodies. Out of 562 patients, 228 (41%) had evidence of enteropathy (Group 1, CD) and 334 (59%) did not (Group 2, NCGS). The most common neurological manifestations were cerebellar ataxia, peripheral neuropathy, and encephalopathy. There was a greater proportion of patients with encephalopathy in Group 1 and with a greater proportion of neuropathy in Group 2. The severity of ataxia did not differ between the two groups. Patients in Group 1 had more severe neuropathy. All patients from both groups responded to gluten-free diet. Anti-tissue transglutaminase (TG2) antibodies were found in 91% of patients in Group 1 and in 29% of patients in Group 2. Comparison between those patients in Group 2 with HLA-DQ2/DQ8 and those without as well as those with positive TG2 compared with those with negative TG2 antibodies identified no differences within these subgroups. Serological positivity for TG6 antibodies was similar in the two groups (67 and 60%).The neurological manifestations of CD and NCGS are similar and equally responsive to a GFD suggestive of common pathophysiological mechanisms.

Dataset Information

The role of HLA-DQ8 beta57 polymorphism in the anti-gluten T-cell response in coeliac disease.

Publications

The role of HLA-DQ8 beta57 polymorphism in the anti-gluten T-cell response in coeliac disease.

Similar Datasets

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