DR3 Haplotype Research Articles

Novel HLA Class I Alleles Outside the Extended DR3 Haplotype Are Protective against Autoimmune Hepatitis

INTRODUCTION:HLA class II allele, DRB1*03:01, is the most common genetic risk factor for autoimmune hepatitis (AIH), but other unrecognized HLA related risks exist.METHODS:We compared the HLA class I (A, B, C) and class II (DR, DQ, DP) typing between patients with well-characterized AIH and healthy controls by high resolution sequencing of the HLA region. Seventy-three patients with AIH and 87 healthy controls were included. Association between HLA alleles and AIH was considered singly and in clusters and adjusted for age, gender, and DRB1*03:01.RESULTS:DRB1*03:01 was singly associated with AIH among whites (odds ratio [OR]: 3.09, P = 0.002) and carriers of DRB1*03:01 also carried DQA*05:01 and DQB1*02:01. Significant HLA class I alleles were associated with AIH including those belonging to the A03 (OR: 0.4, P = 0.01) and B44 supertype (OR: 0.44, P = 0.03). Further refinement of HLA-A by binding pocket structure revealed that the sequence Y(F/T)AVMENV(H/Q)Y, corresponding to HLA-A alleles A*03:01-02; *31:01; *32:02, was protective for AIH (OR: 0.3, P = 0.002). A protective association also existed for alleles belonging to the HLA-B binding pocket structure Y(H/Y)TVKEISNY (OR: 0.35, P = 0.01), corresponding to HLA-B alleles: B*40:01-02; *41:02; *44:02-03; *45:01; *49:01; *50:01-02. Associations with specific class I alleles belonging to the 8.1 ancestral haplotype (HLA-A*01:01, HLA-B*08:01, HLA-C*07:01) were not significant when considered jointly with DRB1*03:01 and reported protective class I alleles.DISCUSSION:Our study identified novel supertypes and HLA-A and B peptide binding structures protective against AIH. Further risk assessment of class I molecules remains important in AIH as they are key mediators of adaptive immunity.

SAT-605 Immune Thrombocytopenic Purpura in Graves' disease

Background: Immune thrombocytopenic purpura (ITP) in association with autoimmune thyroid diseases is a well-known entity. We report a case of Graves’ disease patient with coexisting ITP, where the control of ITP is in close relationship to control with Graves’ disease. Case Presentation: A 17-year-old female presented in 10/2014 with hyperthyroid symptoms for 4-5 months. Thyroid function tests (TFT’s) showed TSH 0.011 (0.45-4.5 mcIU/ml) and Total T4 (TT4) - 34.3 (4.5-12 ug/dl). Thyroid ultrasound showed thyromegaly without any discrete nodules. Thyroid uptake scan showed a homogeneous increased radiotracer uptake of 65% at 24 hours consistent with Graves’ disease and she was started on Methimazole (MMI) 20 mg PO daily. Over time, her hyperthyroidism remained well controlled on MMI 5 mg q other day, hence it was discontinued in 5/2016. She presented with multiple skin bruises in 12/2016 and her platelet count was noted to be 19 (150-400x103/ml). TFT’s remained normal. Her presumptive diagnosis was ITP given another autoimmune condition - Graves’ disease and was started on Prednisone 80 mg daily. She followed with hematology and her platelet count was monitored regularly and prednisone dose was adjusted. In 7/2017 her platelet count dropped to 64 on prednisone 5 mg PO daily. Repeat TFT’s showed TSH 0.01 and free T4 3.31. MMI was resumed at 20 mg PO daily. Labs three months later show TSH 0.024, free T4 0.86, TT3 102 and platelets 186. Given the recurrence of Graves’ disease she underwent radioactive iodine (RAI) I131 therapy in 1/2018. Post RAI she required levothyroxine 50 mcg daily briefly. In 5/2018 her platelet count dropped again to 59 on prednisone. TFT’s showed TSH of 0.014, free T4 1.42 and TT3 117. Graves’ disease relapsed despite RAI therapy and MMI was started at 5 mg PO daily. Her thyroid function remains well controlled on MMI 5 mg PO daily. Her platelet count also returned to normal and remains stable on Prednisone 5 mg PO daily. Discussion: There are several case reports of Graves’ disease and ITP in the literature. Several mechanisms by which thrombocytopenia occurs have been postulated. Accelerated platelet turnover by an activated reticuloendothelial system, shortened platelet survival and consequently reduced platelet counts can occur in patients with hyperthyroidism. Platelet survival return to normal in patients maintained in euthyroid state for more than six months. Genetic predisposition to both Graves’ disease and ITP appears to be related to HLA B8 and DR3 haplotypes. In our patient, each time she had a low platelet count on prednisone therapy, thyroid function tests were suggestive of relapse of Graves’ disease. Treatment of Graves’ disease has resulted in improved response of ITP to glucocorticoid therapy and normalization of platelet count. In patients with ITP on glucocorticoid therapy, unexplained drop in platelet count should prompt checking for thyroid function abnormalities.

The Frequency of Human Leukocyte Antigen Class I and II Alleles and the Relationship Between Haplotypes in Gilaks Population of Iran

Background: The Human Leukocyte Antigen (HLA) is the most polymorphic region in human genome. Moreover, HLA haplotype frequencies are largely used in transplantation, the treatment of autoimmune diseases, and population-based studies. The present study aimed to determine HLA-A, -B, -DR alleles and haplotype frequencies in 88 unrelated donors of Iranian Gilak ethnic group, by Polymerase Chain Reaction with Sequence-Specific Primer (PCR-SSP) assay. The study findings were compared with previous reports on HLA alleles of different Iranian ethnics.Materials and Methods: The blood samples were collected from 88 donors of the Gilak ethnicity. Deoxyribonucleic Acid (DNA) of the samples were extracted. Then, we performed PCR and electrophoresis. The frequency of different alleles was analyzed using software.Results: Our obtained results suggested that the most frequent alleles for HLA-A were A*02 (24.4%), A*11 (17.6%), and A*03 (14.2%), and the same for HLA-B were B*35 (26.7%), B*51 (12.5%), and B*52 (11.4%), and for HLA-DRB1 were DRB1*11 (14.1%), DRB1*01 (13.5%), and DRB1*04 (11.8%). In addition, the most common three-locus haplotypes were A02:B35:DRB01 (9.1%), A68:B49:DRB14 (6.2%), and A11:B51:DRB04 (5.1%) among the studied group.Conclusion: Despite some differences, we found a strong relationship in the allelic variation between Gilak ethnicity and other Iranian and Caucasians ethnics.

Engineered MBP-specific human Tregs ameliorate MOG-induced EAE through IL-2-triggered inhibition of effector T cells

Expanded polyclonal T regulatory cells (Tregs) offer great promise for the treatment of immune-mediated diseases. Inhibition by Tregs is under the control of the T-cell receptor (TCR). Therefore, we created Tregs with defined antigen specificity, using a recombinant T-cell receptor isolated from a myelin-basic protein specific T-cell clone of a multiple sclerosis (MS) patient (Ob2F3). We expressed this TCR using a retroviral expression vector in human Tregs from peripheral blood. We observed that transduced Tregs were activated in vitro in response to myelin basic protein (MBP) peptide on DR15 antigen-presenting cells (APC) and upregulated Treg markers, Foxp3, LAP and Helios. These engineered MBP-specific Tregs could suppress MBP-specific T effector cells, and were also able to suppress T cells with other specificities after Tregs had been activated through the TCR. Importantly, we showed that these engineered Tregs were able to function effectively in the presence of strong TLR-induced inflammatory signals, and that MBP-specific Tregs ameliorated EAE in myelin oligodendrocyte glycoprotein (MOG)-immunized DR15 transgenic mice. We further demonstrated in vitro that IL-2 produced by neighboring effector T cells activated MBP-specific Tregs, initiating contact-independent suppression to T effectors in local milieu. Mechanistic studies demonstrated that bystander suppression in vivo may involve transfer of soluble mediators, enhanced by cell contact between Tregs and effectors. Taken together, we show that engineered clonal MBP-specific Tregs are able to suppress autoimmune pathology in EAE. This approach may serve as a cellular therapy for MS patients with the common DR15 haplotype that is associated with disease susceptibility.

P040 DR2 alleles and haplotypes identified by NGS in diverse world populations

Aim The DR2 supertype currently comprises 204 DRB1∗15 and 65 DRB1∗16 alleles. With few exceptions, DR2 alleles associate with one of 46 DRB5 alleles. DRB5-DRB1-DQA1-DQB1 haplotypes may differ among diverse world populations. We used NGS for HLA genotyping of commercial human population panels composed primarily of unrelated individuals. We report here on the 170 DR2 alleles and haplotypes identified among 541 individuals in 6 sample panels. Methods The sample panels were from the Coriell repository: hapmappt02, hapmappt04, hapmappt05, hapmappt06, MGP00010 and MGP00019. Hapmappt06 represents CEPH family pairs and trios. NGS genotyping of HLA-A, B, C, DRB5, DRB1, DQA1, DQB1, DPA1, DPB1 employed an amplicon based technology assessing all exons with intervening intron data to exclude known null alleles. DRB5-DRB1-DQA1-DQB1 haplotypes were inferred based on common associations in publically available data sets: bioinformatics.bethematchclinical.org and the IMGT HLA database. Results Three DRB1∗15 alleles, two DRB1∗16 and three DRB5 alleles were identified on 12 different haplotypes, see Table. DRB1∗15:01:01 was found in 6 associations. Most frequent was DRB5∗0101:01-DRB1∗15:01:01-DQA1∗01:02:01-DQB1∗06:02:01, found in all panels except Gambian. DRB1∗15:02:01, almost exclusive to Asians, was found in 2 linkages, with DRB5∗01:02-DRB1∗15:02:01-DQA1∗01:03:01-DQB1∗06:01:01 most frequent. DRB1∗15:03:01, on DRB5∗01:01:01-DRB1∗15:03:01-DQA1∗01:02:01-DQB1∗06:02:01, was found only in Nigerian. DRB1∗16:01:01, only in Caucasian, associated with DRB5∗02:02-DQA1∗01:02:02-DQB1∗05:02:01. DRB1∗16:02:01, seen in Asian and Gambian, was found most frequently with DRB5∗02:02-DQA1∗01:02:02-DQB1∗05:02:01, but also with DRB5∗01:01:01-DQA1∗01:02:02-DQB1∗05:02:01. Conclusions Seven DR2 haplotypes appear to be the results of historic recombination events. DR2 alleles and haplotypes are diverse and differ among human populations. Download : Download high-res image (718KB) Download : Download full-size image

FINE-MAPPING OF THE HUMAN LEUKOCYTE ANTIGEN (HLA) LOCUS AS A RISK FACTOR FOR ALZHEIMER'S DISEASE

There is increasing support for the role of neuroinflammation and aberrant immune regulation in the pathophysiology of Alzheimer's disease (AD). The immunoregulatory human leukocyte antigen (HLA) complex has been linked to susceptibility for a number of neurodegenerative diseases including AD, however, studies to date have failed to consistently identify a risk HLA haplotype for AD. Contributing to this difficulty are the complex genetic organization of the HLA region, differences in sequencing and allelic imputation methods, and diversity across ethnic populations. Building on prior work linking the HLA to AD, we used a robust imputation method on two case-control cohorts to examine the relationship between HLA haplotypes and AD risk in 309 individuals from UCSF and 11,381 individuals from the Alzheimer's Disease Genetics Consortium (ADGC), a NIA-funded national data repository. The strongest association with AD risk occurred with MHC haplotype A*03:01∼B*07:02∼DRB1*15:01∼DQA1*01:02∼DQB1*06:02, p=9.6x10-4, odds ratio (95% confidence interval) = 1.2 (1.1–1.4) in the combined UCSF + ADGC cohort. Secondary analysis suggested that this effect may be driven primarily by individuals who are negative for established AD genetic risk factor, APOE E4, and may be of particular relevance in men more than women. Separate analyses of class I and II haplotypes further supported the role of class I haplotype A*03:01∼B*07:02 and class II haplotype DRB1*15:01- DQA1*01:02- DQB1*06:02 (DR15) as risk factors for AD. We also examined cerebrospinal fluid (CSF) biomarker measures and longitudinal cognitive data from the Alzheimer's Disease Neuroimaging Initiative to assess clinical relevance of identified risk haplotypes and found A*03:01∼B*07:02 was associated with higher CSF amyloid levels while DR15 haplotype was associated with greater rates of cognitive decline in a dose-dependent manner. We provide evidence that variation in the HLA—including risk haplotype DR15—contributes to AD risk. DR15 has also been associated with risk for multiple sclerosis, and its component alleles have been implicated in Parkinson's disease and narcolepsy. Our findings thus raise the possibility that DR15-associated mechanisms may contribute to pan-neuronal disease vulnerability. Results must be considered in the context of only representing European-ancestry, clinically diagnosed individuals, and utilizing imputed genotypes for a subset of HLA genes.

The HLA DRB1*03:01 allele is associated with NMO regardless of the NMO-IgG status in Brazilian patients from Rio de Janeiro

The aim of this study was to analyze the HLA class II alleles in neuromyelitis optica (NMO) and MS patients from Rio de Janeiro to clarify whether the pattern of genetic predisposition in NMO is different from the one seen in MS or whether it is possible to determine specific alleles of susceptibility or resistance. The DR3 haplotype was over represented in NMO while the DR15 was over represented in MS. The HLA-DRB1*03:01 allele was associated with NMO regardless the NMO-IgG status but did not influence the long term disability. The comparison of the allele and haplotype frequencies significantly discriminated patients with NMO vs. MS.

The Clinical Course of Patients with Preschool Manifestation of Type 1 Diabetes Is Independent of the HLA DR-DQ Genotype.

Introduction: Major histocompatibility complex class II genes are considered major genetic risk factors for autoimmune diabetes. We analysed Human Leukocyte Antigen (HLA) DR and DQ haplotypes in a cohort with early-onset (age < 5 years), long term type 1 diabetes (T1D) and explored their influence on clinical and laboratory parameters. Methods: Intermediate resolution HLA-DRB1, DQA1 and DQB1 typing was performed in 233 samples from the German Paediatric Diabetes Biobank and compared with a local control cohort of 19,544 cases. Clinical follow-up data of 195 patients (diabetes duration 14.2 ± 2.9 years) and residual C-peptide levels were compared between three HLA risk groups using multiple linear regression analysis. Results: Genetic variability was low, 44.6% (104/233) of early-onset T1D patients carried the highest-risk genotype HLA-DRB1*03:01-DQA1*05:01-DQB1*02:01/DRB1*04-DQA1*03:01-DQB1*03:02 (HLA-DRB1*04 denoting 04:01/02/04/05), and 231 of 233 individuals carried at least one of six risk haplotypes. Comparing clinical data between the highest (n = 83), moderate (n = 106) and low risk (n = 6) genotypes, we found no difference in age at diagnosis (mean age 2.8 ± 1.1 vs. 2.8 ± 1.2 vs. 3.2 ± 1.5 years), metabolic control, or frequency of associated autoimmune diseases between HLA risk groups (each p > 0.05). Residual C-peptide was detectable in 23.5% and C-peptide levels in the highest-risk group were comparable to levels in moderate to high risk genotypes. Conclusion: In this study, we saw no evidence for a different clinical course of early-onset T1D based on the HLA genotype within the first ten years after manifestation.

Fine-mapping of the human leukocyte antigen locus as a risk factor for Alzheimer disease: A case-control study.

BackgroundAlzheimer disease (AD) is a progressive disorder that affects cognitive function. There is increasing support for the role of neuroinflammation and aberrant immune regulation in the pathophysiology of AD. The immunoregulatory human leukocyte antigen (HLA) complex has been linked to susceptibility for a number of neurodegenerative diseases, including AD; however, studies to date have failed to consistently identify a risk HLA haplotype for AD. Contributing to this difficulty are the complex genetic organization of the HLA region, differences in sequencing and allelic imputation methods, and diversity across ethnic populations.Methods and findingsBuilding on prior work linking the HLA to AD, we used a robust imputation method on two separate case–control cohorts to examine the relationship between HLA haplotypes and AD risk in 309 individuals (191 AD, 118 cognitively normal [CN] controls) from the San Francisco-based University of California, San Francisco (UCSF) Memory and Aging Center (collected between 1999–2015) and 11,381 individuals (5,728 AD, 5,653 CN controls) from the Alzheimer’s Disease Genetics Consortium (ADGC), a National Institute on Aging (NIA)-funded national data repository (reflecting samples collected between 1984–2012). We also examined cerebrospinal fluid (CSF) biomarker measures for patients seen between 2005–2007 and longitudinal cognitive data from the Alzheimer’s Disease Neuroimaging Initiative (n = 346, mean follow-up 3.15 ± 2.04 y in AD individuals) to assess the clinical relevance of identified risk haplotypes. The strongest association with AD risk occurred with major histocompatibility complex (MHC) haplotype A*03:01~B*07:02~DRB1*15:01~DQA1*01:02~DQB1*06:02 (p = 9.6 x 10−4, odds ratio [OR] [95% confidence interval] = 1.21 [1.08–1.37]) in the combined UCSF + ADGC cohort. Secondary analysis suggested that this effect may be driven primarily by individuals who are negative for the established AD genetic risk factor, apolipoprotein E (APOE) ɛ4. Separate analyses of class I and II haplotypes further supported the role of class I haplotype A*03:01~B*07:02 (p = 0.03, OR = 1.11 [1.01–1.23]) and class II haplotype DRB1*15:01- DQA1*01:02- DQB1*06:02 (DR15) (p = 0.03, OR = 1.08 [1.01–1.15]) as risk factors for AD. We followed up these findings in the clinical dataset representing the spectrum of cognitively normal controls, individuals with mild cognitive impairment, and individuals with AD to assess their relevance to disease. Carrying A*03:01~B*07:02 was associated with higher CSF amyloid levels (p = 0.03, β ± standard error = 47.19 ± 21.78). We also found a dose-dependent association between the DR15 haplotype and greater rates of cognitive decline (greater impairment on the 11-item Alzheimer’s Disease Assessment Scale cognitive subscale [ADAS11] over time [p = 0.03, β ± standard error = 0.7 ± 0.3]; worse forgetting score on the Rey Auditory Verbal Learning Test (RAVLT) over time [p = 0.02, β ± standard error = −0.2 ± 0.06]). In a subset of the same cohort, dose of DR15 was also associated with higher baseline levels of chemokine CC-4, a biomarker of inflammation (p = 0.005, β ± standard error = 0.08 ± 0.03). The main study limitations are that the results represent only individuals of European-ancestry and clinically diagnosed individuals, and that our study used imputed genotypes for a subset of HLA genes.ConclusionsWe provide evidence that variation in the HLA locus—including risk haplotype DR15—contributes to AD risk. DR15 has also been associated with multiple sclerosis, and its component alleles have been implicated in Parkinson disease and narcolepsy. Our findings thus raise the possibility that DR15-associated mechanisms may contribute to pan-neuronal disease vulnerability.

The Involvement of Tumor Necrosis Factor α in Autoimmune Hepatitis

Background and Aim: Autoimmune Hepatitis (AIH) is an immune mediated and inflammatory liver disease of unknown etiology. The strong association of the HLA haplotypes DR3 and DR4 indicates that in particular the CD4+ T cell response appears to be crucial in AIH pathogenesis. The aim of this study was to characterize extra- and intrahepatic T cells of AIH patients regarding their gene expression and cytokine production profile.

Exploring the Role of Killer Cell Immunoglobulin-Like Receptors and Their HLA Class I Ligands in Autoimmune Hepatitis.

BackgroundNatural killer cells are involved in the complex mechanisms underlying autoimmune diseases but few studies have investigated their role in autoimmune hepatitis. Killer immunoglobulin-like receptors are key regulators of natural killer cell-mediated immune responses.Methods and FindingsKIR gene frequencies, KIR haplotypes, KIR ligands and combinations of KIRs and their HLA Class I ligands were investigated in 114 patients diagnosed with type 1 autoimmune hepatitis and compared with a group of 221 healthy controls. HLA Class I and Class II antigen frequencies were compared to those of 551 healthy unrelated families representative of the Sardinian population. In our cohort, type 1 autoimmune hepatitis was strongly associated with the HLA-B18, Cw5, DR3 haplotype. The KIR2DS1 activating KIR gene and the high affinity HLA-C2 ligands were significantly higher in patients compared to controls. Patients also had a reduced frequency of HLA-Bw4 ligands for KIR3DL1 and HLA-C1 ligands for KIR2DL3. Age at onset was significantly associated with the KIR2DS1 activating gene but not with HLA-C1 or HLA-C2 ligand groups.ConclusionsThe activating KIR gene KIR2DS1 resulted to have an important predictive potential for early onset of type 1 autoimmune hepatitis. Additionally, the low frequency of the KIR-ligand combinations KIR3DL1/HLA-Bw4 and KIR2DL3/HLA-C1 coupled to the high frequency of the HLA-C2 high affinity ligands for KIR2DS1 could contribute to unwanted NK cell autoreactivity in AIH-1.

Uncommon DR7-DR53-DQ haplotypes in four canadian subjects

Aim To describe uncommon DR7-DR53-DQ haplotypes in four Canadian subjects that deviate from the frequent common association between DR7, DR53 and DQ antigens. Methods Medium resolution HLA typing for HLA- DRB1, DRB3/4/5 and DQB1 loci were performed using Luminex based SSO kits (One Lambda Labtype). A high resolution typing using SSP for DRB4 (Olerup SSP kit) and SBT for DRB1 and DQB1 (Life Technologies) were further performed to evaluate these uncommon haplotypes. Results We detected presence of DRB4 ∗ 01:01 instead of more frequent DRB4 ∗ 01:03N in association with the DR7 and DQ9 haplotype in two Canadian subjects. Furthermore, we also detected DRB4 null allele in association with DR7 and DQ2 in a kidney transplant recipient and a bone marrow patient (Table 1). Conclusion Here, we report two cases of DRB1∗07, DRB4∗01, DQB1∗03:03 haplotype and two cases of DRB4∗01:03N null allele in association with DRB1 ∗ 07:01 and DQB1 ∗ 02:02 haplotype . Our findings are in disparity to reported common linkages in which DR7- DQ9 haplotype is commonly seen in association with the null allele DRB4 ∗ 01:03:01:02N . There are 15 alleles of DRB4; 12 of them produce an expressed DR53 antigen and 3 resulting in null alleles. The presence of these rare haplotypes might be due to unidirectional or bidirectional homologous recombination event that happened between the DR7, DR53, DQ2 and the DR7, DR53- null, DQ9 haplotypes. This is supported by the presence of reported DR7-DQ2 haplotype with a DRB4 null allele. It might also be due to point mutation in DRB4∗01:03:01 changing the splice site in case of DR7, DR53null, DQ2 haplotype. Understanding the genetics and expression of DRB4 gene is of clinical relevance in the hematopoetic stem cell transplant, both GVHD and graft rejection, in solid organ transplant especially effect of donor specific antibodies, and in disease association with autoimmune disorders, such as celiac, Crohn’s disease, myasthenia gravis, rheumatoid arthritis, Hashimoto’s thyroiditis, vitiligo, primary biliary cirrhosis and ALL in children. Download full-size image

Novel antigen expression of HLA-DR53 in patients with DR7 and DQ9 haplotype

An unusual HLA genotype association of DRB1∗07:01 and DQB1∗03:03 haplotype, expressing DRB4∗01, were identified in two Caucasian patients. The HLA phenotype of these patients showed the presence of DR53 with DR7 and DQ9 haplotype. The common null allele DRB4∗01:03N and the non-common associated DRB4∗01 were typed using serology (One Lambda), SSP Class II null tray and DR/DQ low and high resolution (One Lambda), SSO (One Lambda) and Real-Time PCR (Linkage). Typings were performed in parallel with other known patients to confirm these findings. The interpretation of all tests confirmed the DRB genotype to be DRB1∗07:01, DRB4∗01:01, DRB4∗03:01N. This unexpected expression of the DRB4∗01 with the DRB1∗07:01 and DQB1∗03:03 haplotype was seen only once before in a leukemia patient (Lardy et al., 1998). Sequencing studies are needed to collect more data and to determine the frequency of the linkage disequilibrium between the DRB1∗07:01 and DQB1∗03:03 haplotype expressing DRB4∗01. Serology typing played an important role determining these results because it indicated reflex testing to DNA typing was needed. Even though the DRB1∗07:01, DRB4∗01:03N and DQB1∗03:03 haplotype is common and the frequency is nearly 100%, the expression of the DRB4∗01 gene could be present when there is the DRB1∗07:01 and DQB1∗03:03 haplotype. Additional typing to determine the presence of DRB4∗01 should be considered in specific cases. For example, identifying this DRB4∗01 allele in organ donors is important to avoid the allocation of organs to patients with antibodies to DR53. Unexpected positive B-cell crossmatch in recipients with antibodies to DR53, when the donor has expressed DRB1∗07:01and DQB1∗03:03, should be investigated due to the possibility of the presence of DRB4∗01. Detecting this antigen on donors may be especially important for recipients with antibody to DR53, since expression of DR53 antigen on the donor may increase the possibility of antibody mediated rejection.Download : Download full-size image

Association of HLA-DQA1 and -DQB1 alleles with type I diabetes in Arabs: a meta-analyses.

This study aimed at assessing the nature and significance of associations between various alleles of HLA-DQA1, HLA-DQB1, and type I diabetes (T1D) in Arab populations. Evidence from literature (published before 20 April 2015) was amassed and analysed through multiple meta-analyses, which yielded effect summary odds ratios and 95% confidence intervals for 24 alleles and 4 haplotypes. A total of 1273 cases and 1747 controls from 16 studies were analysed. High levels of significance were obtained to support higher T1D risk when harbouring DQA1*03:01. The alleles DQB1*02:01 and *03:02 and the haplotypes DR3 and DR4 were significant risk factors, albeit with high publication heterogeneity. The protective effects of DQA1*01:01, DQB1*05:03, *06:02, *06:03, and *06:04 were robustly suggested by all indicators of meta-analyses. The haplotypes DR7 and DR11 were strongly suggested to be protective in Arabs. A relatively small number of studies have emerged from Arab countries, mostly with inadequate power on an individual basis. This study fills the gap by providing significant size effect of human leukocyte antigen (HLA) alleles and completes the continuum of global ethnic differences in this context.

CD40 expression on CD4+ T cells (Th40 cells) as a biomarker for multiple sclerosis (HUM3P.265)

Abstract Multiple Sclerosis is a neurodegenerative disease with autoimmune components. Diagnosis is invasive and time consuming. The etiology is unclear as are clues for disease progression. The autoimmune components have largely been defined in the EAE mouse model. The problem has been defining a reliable biomarker for pathogenic cells. We described a unique T cell subset, Th40 cells that is highly auto-aggressive. We compared Th40 levels in clinically isolated syndrome (CIS), relapsing/remitting (RRMS), secondary progressive (SPMS) and primary progressive (PPMS) patients to non-autoimmune controls. MS subjects have significantly increased percentages of Th40 cells compared to controls. In CIS and RRMS Th40 cell levels cover a broad range while in SPMS and PPMS the range is centralized. Longitudinal studies show that Th40 cell levels remain elevated. Th40 cells produce IFNg, TNFa and IL-17. HLA haplotypes were diverse with only 50% of patients expressing the DR2 (DR15) haplotype or DR3 and DR4. Th40 cells are significantly elevated in MS regardless of HLA haplotype and responded to CNS antigens creating antigen signatures. The ratio of Th40 to or to Tr1 cells is 7 to 1. Th40 cells have a memory phenotype. The chemokine receptors CCR5 and CXCR3 were detected. Samples from patients on disease-modifying-therapy (DMT) demonstrated lymphopenia, but the Th40 percentage was not altered. Th40 cells provide a unique diagnostic tool for MS with significant improvement over current options.

OR18: IMMUNOGENETIC BASIS OF TYPE 1 DIABETES IN THE INDIAN POPULATION

Type 1 diabetes (T1D) is known to have a strong genetic influence with an association of > 40 regions of genome. The primary association of T1D has been reported with both HLA class I and class II genes. Very few reports are available on other HLA and non HLA genes. In our study, the disease was found to be associated with multiple HLA-DR3 +ve haplotypes that include B8-DR3, B58-DR3 and B50-DR3. While former two are equivalent to those observed in Caucasian and Chinese populations respectively, B50-DR3 is a ‘unique’ Indian haplotype that shows positive association with disease. On the other hand the classical Caucasian AH8.1 haplotype is rare in the Indian population and has been replaced by a variant from AH8.1v along with several additional haplotypes that include HLA-A26-B8-DR3 (AH8.2), A24-B8-DR3 (AH8.3), A3-B8-DR3 (AH8.4), A2-B8-DR3 (AH8.6) and others. Of these, AH8.2 is the most common and represents 43% of total B8-DR3 haplotypes. Significant association with the disease was observed with AH8.2 (p = 2.9E-6), AH8.3 (p = 2E-5), AH8.6 (p = 1.1E-7), B50-DR3 (p = 7.5E-12) and B58-DR3 (p = 7.5E-12). Fine molecular analysis employing multiple microsatellite markers and SNPs interspersed in HLA class I, class II and class III regions revealed that Indian B8-DR3 haplotypes differ significantly from the Caucasian AH8.1 at multiple loci. For example, Indian B8-DR3 haplotypes have HLA-Cw∗07:02, DRB3∗02:02, HSP70–21267A, TNFA-308G, TNFa105, C4A1, BF∗FB and differ at several loci in the central MHC region from the Caucasian AH8.1. Further, Indian haplotypes are characterized by HLA-DRB1∗03:01-DQA1∗05:01-DQB1∗02:01 suggesting that these might have evolved independently from a ‘common ancestor’ through selective recombination and mutation events. Additionally, T1D risk conferred by DR3 haplotypes in India might be influenced by the presence of DRB3∗02:02 which is in contrast to that in Caucasians, majority of whom have DRB3∗01:01. SNP analysis in non-MHC genes including CTLA4 and PTPN22 revealed that the former was associated with younger age of disease onset and latter with presence of GAD65 and IA2 autoantibodies in patients. These findings have important implications in understanding the extent of genetic influence on autoimmune diseases and for defining the evolutionary significance of disease associated haplotypes.

P080 : BIOLOGICAL SIGNIFICANCE OF HLA-G IN TYPE 1 DIABETES SUSCEPTIBILITY AMONG NORTH INDIANS

Introduction T1D predisposition due to MHC region, particularly with HLA-DR3/DR4 and DQ2/DQ8 is reported worldwide, however not all DR3 or DR4 haplotypes predispose equally to the disease and role of several other genetic factors is also reported. HLA-G, a non classical HLA class I molecule with immunosuppressive role is involved in maintenance of tolerance and maintain the immune homeostasis in between aggressive and tolerable immune repertoire in various autoimmune diseases and transplantation. The HLA-G exon 8 14bp insertion/deletion polymorphism influences stability of mRNA and soluble HLA-G (sHLA-G) levels. Induction of HLA-G expression induced the inhibition of autologous T cell activation, indicating role in diabetes pathogenesis. Aim The present study was aimed at evaluating the possible association of 14bp INDEL polymorphism and soluble HLA-G with T1D in North Indian population. Study subjects included 85 T1D cases from our centre and ethnically matched 113 healthy controls (HCs). Results We analysed study cohort on the basis of HLA-G 14bp INDEL polymorphism and the presence/absence of the T1D susceptibility HLA allele (DR3). Among the DR3+ve group, the +/+ 14bp genotype was more common in patients than controls (32% vs 19%). On the other hand, −/−14bp was more frequent in the HCs (47% vs 31%) than patients. Similar analysis of DR3−ve cohort revealed that a higher number of T1D cases carried +/+ genotype (43% vs 22%). Further we observed higher soluble HLA-G in healthy cohort with +/+14bp polymorphism (51 ng/μl). Further, the soluble HLA-G analysis clearly indicated that the sHLA-G levels in T1D patients (with and without DR3 alleles) were lower in comparison to healthy controls (8 ng/μl vs 41 ng/μl). Again segregation of DR3 +ve and −ve T1D cohort on basis of the presence of 14bp INDEL polymorphism and soluble HLA-G levels, we observed decreased sHLA-G in DR3 positive T1D subjects with ins/ins 14bp in comparison to DR3negative with ins/ins14bp respectively (2 ng/μl vs 10 ng/μl). Conclusion These findings suggest combination of ins/ins 14bp genotype and the DR3 alleles probably induced the autoreactive T cells and sHLA-G may influence the balance of classical and non classical immune system in the diabetes pathogenesis in our study cohort.

HLA haplotype DR3–DQ2 confers a high risk of coeliac disease autoimmunity and coeliac disease in early childhood

HLA haplotype DR3–DQ2 confers a high risk of coeliac disease autoimmunity and coeliac disease in early childhood

HLA similarities indicate shared genetic risk in 21‐hydroxylase autoantibody positive South African and United States Addison's disease

Genetic similarities between patients from the United States and South African (SA) Addison's Disease (AD) strengthen evidence for genetic association. SA-AD (n = 73), SA healthy controls (N = 78), and US-AD patients (N = 83) were genotyped for DQA1, DQB1, DRB1, and HLA-B alleles. Serum was tested for the quantity of 21OH-AA and IFNα-AA at the Barbara Davis Center. Although not as profound as in US-AD, in SA-AD 21OH-AA + subjects the predominantly associated risk haplotypes were DRB1*0301-DQB1*0201 (DR3), DRB1*04xx-DQB1*0302 (DR4), and the combined DR3/4 genotype. DQB1*0302 associated DRB1*04xx haplotypes conferred higher risk than those DRB1*04xx haplotypes associated with other DQB1 alleles. We found negative association in 21OH-AA + SA-AD for DQA1*0201-DQB1*0202 and DQA1*0101-DQB1*0501 vs SA controls, and positive association for DQA1*0401-DQB1*0402 vs US-AD. Apart from the class II DR3 haplotype, HLA-B8 did not have an independent effect; however together DR3 and HLA-B8 conferred the highest risk vs 21OH-AA negative SA-AD and SA-controls. HLA-B7 (often with DR4) conferred novel risk in 21OH-AA + SA-AD vs controls. This study represents the first comparison between South African and United States AD populations utilizing genotyping and serology performed at the same center. SA-AD and US-AD 21OH-AA + patients share common HLA risk haplotypes including DR4 (with HLA-B7) and DR3 (with HLA-B8), strengthening previously described HLA associations and implicating similar genetic etiology.

Risk of Pediatric Celiac Disease According to HLA Haplotype and Country

BackgroundThe presence of HLA haplotype DR3–DQ2 or DR4–DQ8 is associated with an increased risk of celiac disease. In addition, nearly all children with celiac disease have serum antibodies against tissue transglutaminase (tTG).MethodsWe studied 6403 children with HLA haplotype DR3–DQ2 or DR4–DQ8 prospectively from birth in the United States, Finland, Germany, and Sweden. The primary end point was the development of celiac disease autoimmunity, which was defined as the presence of tTG antibodies on two consecutive tests at least 3 months apart. The secondary end point was the development of celiac disease, which was defined for the purpose of this study as either a diagnosis on biopsy or persistently high levels of tTG antibodies.ResultsThe median follow-up was 60 months (interquartile range, 46 to 77). Celiac disease autoimmunity developed in 786 children (12%). Of the 350 children who underwent biopsy, 291 had confirmed celiac disease; an additional 21 children who did not undergo biopsy had persistently high levels of tTG antibodies. The risks of celiac disease autoimmunity and celiac disease by the age of 5 years were 11% and 3%, respectively, among children with a single DR3–DQ2 haplotype, and 26% and 11%, respectively, among those with two copies (DR3–DQ2 homozygosity). In the adjusted model, the hazard ratios for celiac disease autoimmunity were 2.09 (95% confidence interval [CI], 1.70 to 2.56) among heterozygotes and 5.70 (95% CI, 4.66 to 6.97) among homozygotes, as compared with children who had the lowest-risk genotypes (DR4–DQ8 heterozygotes or homozygotes). Residence in Sweden was also independently associated with an increased risk of celiac disease autoimmunity (hazard ratio, 1.90; 95% CI, 1.61 to 2.25).ConclusionsChildren with the HLA haplotype DR3–DQ2, especially homozygotes, were found to be at high risk for celiac disease autoimmunity and celiac disease early in childhood. The higher risk in Sweden than in other countries highlights the importance of studying environmental factors associated with celiac disease. (Funded by the National Institute of Diabetes and Digestive and Kidney Diseases and others.)