Islet cell hyperexpression of HLA class I antigens: a defining feature in type 1 diabetes (original) (raw)
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The American Journal of Pathology, 2015
The cause of type 1 diabetes remains unknown. To dissect the link between hyperexpression of human leukocyte antigen (HLA) class I on the islet cells, we examined its expression in subjects with recent-onset type 1 diabetes. IHC showed seemingly pronounced hyperexpression in subjects with recent-onset type 1 diabetes, as well as in some nondiabetic subjects. In all subjects, HLA class I expression on exocrine tissue was low. However, no difference in the level of HLA class I expression was found between islet and exocrine tissue using Western blot, flow cytometry, real-time quantitative PCR, or RNA sequencing analyses. Also, the level of HLA class I expression on the messenger level was not increased in islets from subjects with recent-onset type 1 diabetes compared with that in nondiabetic subjects. Consistently, the HLA class I specific enhanceosome (NLRC5) and related transcription factors, as well as interferons, were not enhanced in islets from recent-onset type 1 diabetic subjects. In conclusion, a discrepancy in HLA class I expression in islets assessed by IHC was observed compared with that using quantitative techniques showing similar expression of HLA class I in islets and exocrine tissue in subjects with recent-onset type 1 diabetes, nor could any differences be found between type 1 diabetic and nondiabetic subjects. Results presented provide important clues for a better understanding on how this complex disease develops. (Am J Pathol 2015, 185: 129e138; http://dx.The cause of type 1 diabetes remains unknown. The disease seems to be a result of a complex interplay between genetic predisposition, the immune system, and environmental factors. Pancreas is a difficult organ to study, and the methodological options in studying living islets are extremely limited. Most published studies describe pancreatic materials collected post-mortem. An updated review summarizes the present knowledge of the morphological characteristics and insulitis in type 1 diabetes. 2 Although these studies have provided new insight in the inflammatory process in humans with type 1 diabetes, these materials have several disadvantages because of post-mortem autolysis, patient heterogeneity, and lack of clinical information. In The Diabetes Virus Detection (DiViD) Study, fresh pancreatic tissue was collected from living newly diagnosed type 1 diabetic patients shortly after diagnosis, and used in the present study. 3
HLA genes associated with autoimmunity and progression to disease in type 1 diabetes
Tissue Antigens, 2003
Insulin dependent diabetes mellitus (type I DM) is caused by an autoimmune process which culminates in destruction of pancreatic beta cells with resultant loss of insulin production. Preceding the clinical diagnosis of type I DM is a preclinical stage characterized by autoantibodies to insulin, glutamic acid decarboxylase (GAD) and a tyrosine phosphatase-like molecule (IA-2). We have studied both HLA class I and class 2 allele distributions in diabetic probands and autoantibody positive individuals in members of 452 families recruited for the Australian type I diabetes DNA repository. The results demonstrate that progression to autoimmunity as measured by the appearance of autoantibodies is strongly associated with the class 2 alleles DRB1*03 and DRB*04 and with DRB1*03/04 heterozygosity. In contrast, the progression to clinical disease appears associated with class I alleles A24, A30 and B18 while A1, A28, B14 and B56 appear negatively associated. The class 2 alleles appear to have a minimal role in the progression from autoantibody positivity to clinical disease. These results are consistent with the view that CD4 þ T cells responding to peptides in the context of class 2 molecules are responsible for initiating autoantibody production, while the destruction of islet cells leading to clinical expression of the disease is the function of CD8 þ T cells recognizing relevant peptides in the context of class I molecules.
Recognition of HLA Class I–Restricted β-Cell Epitopes in Type 1 Diabetes
Diabetes, 2006
Type 1 diabetes results from the autoimmune destruction of insulin-producing pancreatic β-cells by cytotoxic T-lymphocytes (CTLs). In humans, few β-cell epitopes have been reported, thereby limiting the study of β-cell–specific CTLs in type 1 diabetes. To identify additional epitopes, HLA class I peptide affinity algorithms were used to identify a panel of peptides derived from the β-cell proteins islet amyloid polypeptide (IAPP), islet-specific glucose-6-phosphatase catalytic subunit–related protein (IGRP), insulin, insulinoma-associated antigen 2 (IA-2), and phogrin that were predicted to bind HLA-A*0201. Peripheral blood mononuclear cells from 24 HLA-A*0201 recent-onset type 1 diabetic patients and 11 nondiabetic control subjects were evaluated for γ-interferon secretion in response to peptide stimulation in enzyme-linked immunospot assays. We identified peptides IAPP9-17, IGRP215-223, IGRP152-160, islet IA-2(172-180), and IA-2(482-490) as novel HLA-A*0201–restricted T-cell epito...
Clinical and Experimental Immunology, 2010
Summary Type 1 diabetes (T1D) is caused by the selective destruction of the insulin-producing β cells of the pancreas by an autoimmune response. Due to ethical and practical difficulties, the features of the destructive process are known from a small number of observations, and transcriptomic data are remarkably missing. Here we report whole genome transcript analysis validated by quantitative reverse transcription–polymerase chain reaction (qRT–PCR) and correlated with immunohistological observations for four T1D pancreases (collected 5 days, 9 months, 8 and 10 years after diagnosis) and for purified islets from two of them. Collectively, the expression profile of immune response and inflammatory genes confirmed the current views on the immunopathogenesis of diabetes and showed similarities with other autoimmune diseases; for example, an interferon signature was detected. The data also supported the concept that the autoimmune process is maintained and balanced partially by regener...
Non-HLA type 1 diabetes genes modulate disease risk together with HLA-DQ and islet autoantibodies
Genes and Immunity, 2015
The possible interrelations between HLA-DQ, non-HLA single nucleotide polymorphisms (SNPs) and islet autoantibodies were investigated at clinical onset in 1-34 year old type 1 diabetes (T1D) patients (n=305) and controls (n=203). Among the non-HLA SNPs reported by the Type 1 Diabetes Genetics Consortium, 24% were supported in this Swedish replication set including that the increased risk of minor PTPN22 allele and high risk HLA was modified by GAD65 autoantibodies. The association between T1D and the minor AA+AC genotype in ERBB3 gene was stronger among IA-2 autoantibody-positive patients (comparison p=0.047). The association between T1D and the common insulin (AA) genotype was stronger among insulin autoantibody (IAA)-positive patients (comparison p=0.008). In contrast, the association between T1D and unidentified 26471 gene was stronger among IAA-negative (comparison p=0.049) and IA-2 autoantibody-negative (comparison p=0.052) patients. Finally, the association between IL2RA and T1D was stronger among IAA-positive than among IAA-negative patients (comparison p=0.028). These results suggest that the increased risk of T1D by non-HLA genes is often modified by both islet autoantibodies and HLA-DQ. The interactions between non-HLA genes, islet autoantibodies Users may view, print, copy, and download text and data-mine the content in such documents, for the purposes of academic research, subject always to the full Conditions of use:
Diabetes, 2006
Cytotoxic T-lymphocytes (CTLs) are considered to be essential for β-cell destruction in type 1 diabetes. However, few islet-associated peptides have been demonstrated to activate autoreactive CTLs from type 1 diabetic subjects. In an effort to identify novel epitopes, we used matrix-assisted algorithms to predict peptides of glial fibrillary acidic protein (GFAP), prepro-islet amyloid polypeptide (ppIAPP), and islet-specific glucose-6-phosphatase catalytic subunit–related protein (IGRP) that likely bind to HLA-A*0201 with a strong affinity and contain a COOH-terminal proteasomal cleavage site. Seven peptides stabilized HLA-A*0201 expression in binding assays and were used to stimulate peripheral blood mononuclear cells and were evaluated for granzyme B secretion. We found that 5 of 13 type 1 diabetic subjects and 4 of 6 antibody-positive relatives exhibited greater numbers of granzyme B–secreting cells in response to at least one putative epitope compared with healthy control subjec...
The Journal of Immunology, 2006
In both humans and NOD mice, particular MHC genes are primary contributors to development of the autoreactive CD4 ؉ and CD8 ؉ T cell responses against pancreatic  cells that cause type 1 diabetes (T1D). Association studies have suggested, but not proved, that the HLA-A*0201 MHC class I variant is an important contributor to T1D in humans. In this study, we show that transgenic expression in NOD mice of HLA-A*0201, in the absence of murine class I MHC molecules, is sufficient to mediate autoreactive CD8 ؉ T cell responses contributing to T1D development. CD8 ؉ T cells from the transgenic mice are cytotoxic to murine and human HLA-A*0201-positive islet cells. Hence, the murine and human islets must present one or more peptides in common. Islet-specific glucose-6-phosphatase catalytic subunit-related protein (IGRP) is one of several important T1D autoantigens in standard NOD mice. Three IGRP-derived peptides were identified as targets of diabetogenic HLA-A*0201-restricted T cells in our NOD transgenic stock. Collectively, these results indicate the utility of humanized HLA-A*0201-expressing NOD mice in the identification of T cells and autoantigens of potential relevance to human T1D. In particular, the identified antigenic peptides represent promising tools to explore the potential importance of IGRP in the development of human T1D.