Search

Context Validated assays to measure autoantigen-specific T-cell frequency and phenotypes are needed for assessing the risk of developing diabetes, monitoring disease progression, evaluating responses to treatment, and personalizing antigen-based therapies. Objective Toward this end, we performed a technical validation of a tetramer assay for HLA-DRA-DRB1*04:01, a class II allele that is strongly associated with susceptibility to type 1 diabetes (T1D). Methods HLA-DRA-DRB1*04:01-restricted T cells specific for immunodominant epitopes from islet cell antigens GAD65, IGRP, preproinsulin, and ZnT8, and a reference influenza epitope, were enumerated and phenotyped in a single staining tube with a tetramer assay. Single and multicenter testing was performed, using a clone-spiked specimen and replicate samples from T1D patients, with a target coefficient of variation (CV) less than 30%. The same assay was applied to an exploratory cross-sectional sample set with 24 T1D patients to evaluate the utility of the assay. Results Influenza-specific T-cell measurements had mean CVs of 6% for the clone-spiked specimen and 11% for T1D samples in single-center testing, and 20% and 31%, respectively, for multicenter testing. Islet-specific T-cell measurements in these same samples had mean CVs of 14% and 23% for single-center and 23% and 41% for multicenter testing. The cross-sectional study identified relationships between T-cell frequencies and phenotype and disease duration, sex, and autoantibodies. A large fraction of the islet-specific T cells exhibited a naive phenotype. Conclusion Our results demonstrate that the assay is reproducible and useful to characterize islet-specific T cells and identify correlations between T-cell measures and clinical traits. [ABSTRACT FROM AUTHOR]

Characterization of the novel HLA‐DRB1*04:311 and HLA‐DRB1*11:277 alleles in two Greek individuals of Cretan origin. [ABSTRACT FROM AUTHOR]

The HLA region is responsible for almost 50% of the genetic risk of type 1 diabetes (T1D). However, haplotypes and their effects on risk or protection vary among different ethnic groups, mainly in an admixed population. We aimed to evaluate the HLA class II genetic profile of Brazilian individuals with T1D and its relationship with self-reported color/race. This was a nationwide multicenter study conducted in 10 Brazilian cities. We included 1,019 T1D individuals and 5,116 controls matched for the region of birth and self-reported color/race. Control participants belonged to the bone marrow transplant donor registry of Brazil (REDOME). HLA-class II alleles (DRB1, DQA1, and DQB1) were genotyped using the SSO and NGS methods. The most frequent risk and protection haplotypes were HLA~DRB1*03:01~DQA1*05:01 g~DQB1*02:01 (OR 5.8, p < 0.00001) and HLA~DRB1*07:01~DQA1*02:01~DQB1*02:02 (OR 0.54, p < 0.0001), respectively, regardless of self-reported color/race. Haplotypes HLA~DRB1*03:01~DQA1*05:01 g~DQB1*02:01 and HLA~DRB1*04:02~DQA1*03:01 g~DQB1*03:02 were more prevalent in the self-reported White group than in the Black group (p = 0.04 and p = 0.02, respectively). The frequency of haplotype HLA~DRB1*09:01~DQA1*03:01 g~DQB1*02:02 was higher in individuals self-reported as Black than White (p = <0.00001). No difference between the Brazilian geographical regions was found. Individuals with T1D presented differences in frequencies of haplotypes within self-reported color/race, but the more prevalent haplotypes, regardless of self-reported color/race, were the ones described previously in Europeans. We hypothesize that, in the T1D population of Brazil, although highly admixed, the disease risk alleles come mostly from Europeans as a result of centuries of colonization and migration. [ABSTRACT FROM AUTHOR]

Objective: HLA class II alleles are major determinants of genetic predisposition to rheumatic diseases. Predisposing effects of HLA had been suggested in AOSD, however, ethnic differences may account for variations in AOSD association with HLA. We determined the contribution of HLA-DQB1, DPB1 alleles to susceptibility to Adult-onset Still's disease (AOSD) in the Japanese population. Methods: HLA-DQB1 and DPB1 alleles were analyzed in 87 Japanese patients with AOSD and 413 Japanese healthy subjects. Results: We found significant association between HLA-DQB1*06:02 (Pc¼0.010, odds ratio: 2.54) and AOSD, whereas there was no association between the DQB1*06:02 allele and disease phenotypes of AOSD. Moreover, we did not find a predisposing effect of the HLA-DPB1 allele to AOSD. Haplotype analysis showed that presence of DRB1*15:01-DQB1*06:02 was associated with Japanese patients with AOSD. However, conditional logistic regression tests were unable to demonstrate independent association between DRB1*1501 or DQB1*0602 and AOSD. Conclusions: Our results show significant association between AOSD and the HLA DQB1*06:02 allele, and between the DRB1*1501-DQB1*06:02 haplotype and AOSD susceptibility. These findings suggest that genetic susceptibility to AOSD depends on the genotype combinations of HLA DRB1 and DQB1 alleles. [ABSTRACT FROM AUTHOR]

Feto-maternal microchimerism (FMM) involves bidirectional cross-placental trafficking during pregnancy, leading to a micro-chimeric state that can persist for decades. In this manner a pregnant woman will harbor cells from her mother, as well as, cells from her child. Historically, eclampsia, a severe disorder of pregnancy provided the basis for FMM following the detection of trophoblast cells in the lungs of deceased women. Bi-directional cell trafficking between mother and fetus is also altered in pre-eclampsia and has been suggested to contribute to the underlying etiology. FMM has been implicated in tolerance promotion, remission of auto-inflammatory disorders during pregnancy, or the development of autoimmune conditions post-partum. The underlying mechanism whereby the host immune system is modulated is unclear but appears to involve HLA class II molecules, in that incompatibility between mother and fetus promotes remission of rheumatoid arthritis, whereas feto-maternal HLA compatibility may assist in the post-partum initiation of scleroderma. Couples having a high degree of HLA class II compatibility have an increased risk for pre-eclampsia, while the occurrence of scleroderma and rheumatoid arthritis is greater in pre-eclamptic cases than in women with normal pregnancies, suggesting a long term autoimmune predisposition. Since pregnant women with pre-eclampsia exhibit significantly lower levels of maternally-derived micro-chimerism, the question arises whether pre-eclampsia and post-partum development of autoimmune conditions occur due to the failure of the grandmothers cells to adequately regulate an inappropriate micro-chimeric constellation. [ABSTRACT FROM AUTHOR]

Background: Rheumatoid arthritis (RA) is a systemic disease that causes progressive joint damage and disability. Inflammatory cytokines, including tumor necrosis factor (TNF), and IL-6, which are mainly produced by macrophages, play a central role in the development of synovitis. For example, TNF play major role in the expression of adhesion molecules and inflammatory chemokines which, in combination, facilitate increase inflammatory leukocytes and severe inflammatory responses. In addition to environmental factors, genetic constitution of hosts seems to play a crucial role in acquiring the disease and its development. The current study was carried out for the detection of any association of HLA-class 11 (DR, DQ) with RA disease by genotyping in Iraqi patients, as well as to provide information about genotypes that may confer susceptibility or resistance to the development of the disease. Aim of the study: to assess the role, strength and profile of immune response in patients with rheumatoid arthritis by estimation of TNF- α, IL-10 and levels in compare to healthy control group. And to identify any role for certain alleles in exposure to the disease. Material and Method: Five ml of venous blood samples withdrawn from 30 patients suffering from confirmed Rheumatoid arthritis disease, 19 patients were females and 11 males in addition to 30 healthy control samples were enrolled in this study all samples were subjected for (ELISA test) (Enzyme Linked Immunosorbent assay) to estimate the TNF- α, and IL-10 Levels by using the three ml of blood to extract the serum. Another two ml was used for DNA extraction, and then HLA-Class Il genotyping was performed by polymerase chain reaction-sequence specific oligonucleotide probes (PCR-SSO). Results: A highly statistically significant variation both in TNF - α levels, and IL-10 between RA patients group and healthy control group was observed, the P value was <0.001 No statically significant differences between males and females in frequency of the RA with 0.119 P value. HLA-class II genotyping of RA patients in compare with healthy control reflect significant differences in some alleles. Among DR alleles there were some alleles showed higher frequency in control group; DR*0403 allele showed increase frequency in control groups with 35% compared with 6.67% in patients group, and the P value was 0.020, which is considered as statistically significant Another DR*701 allele showed increase frequency in patients groups with 9 cases 30% and the P value was 0.007. Concerning DQ allele's genotyping no significant allele's frequency was noticed. Although *0202 allele occurred in 40% of patients group and 15% in control groups it was not significant statistically as the P value was more than 0.05. [ABSTRACT FROM AUTHOR]

Background: Knowledge of major histocompatibility complex (MHC) composition and distribution in rhesus macaque colonies is critical for management strategies that maximize the utility of this model for biomedical research. Methods: Variation within the Mamu‐A and Mamu‐B (class I) and DRB,DQA/B, and DPA/B (class II) regions of 379 animals from the Caribbean Primate Research Center's (CPRC) specific pathogen free (SPF) colony was examined using massively parallel sequencing. Results: Analyses of the 7 MHC loci revealed a background of Indian origin with high levels of variation despite past genetic bottlenecks. All loci exhibited mutual linkage disequilibria while conforming to Hardy–Weinberg expectations suggesting the achievement of mutation‐selection balance. Conclusion: The CPRC's SPF colony is a significant resource for research on AIDS and other infectious agents. Characterizing colony‐wide MHC variability facilitates the breeding and selection of animals bearing desired haplotypes and increases the investigator's ability to understand the immune responses mounted by these animals. [ABSTRACT FROM AUTHOR]

Defining worldwide human genetic variation is a critical step to reveal how genome plasticity contributes to disease. Yet, there is currently no metric to assess the representativeness and completeness of current and widely used data on genetic variation. We show here that Human Leukocyte Antigen (HLA) genes can serve as such metric as they are both the most polymorphic and the most studied genetic system. As a test case, we investigated the 1,000 Genomes Project panel. Using high-accuracy in silico HLA typing, we find that over 20% of the common HLA variants and over 70% of the rare HLA variants are missing in this reference panel for worldwide genetic variation, due to undersampling and incomplete geographical coverage, in particular in Oceania and West Asia. Because common and rare variants both contribute to disease, this study thus illustrates how HLA diversity can detect and help fix incomplete sampling and hence accelerate efforts to draw a comprehensive overview of the genetic variation that is relevant to health and disease. [ABSTRACT FROM AUTHOR]

Characterization of HLA‐DQB1*03:439 allele in a Greek individual of Cretan origin. [ABSTRACT FROM AUTHOR]

Infants born to HBV carrier mothers are persistently at a higher risk for HBV infection. We investigated the association between HLA SNPs and low responsiveness to HBV vaccination, and the differences of immune response in carriers of risk genotypes who received different doses of the vaccination. 1040 infants from the prevention of mother-to-infant transmission of HBV cohort were included. Infants born to HBsAg (+) and HBeAg (−)/HBeAg (+) mothers received 10 μg/20 μg hepatitis B vaccine, respectively. Rs2857127, rs3135338, rs477515, rs9277554 and rs9286790 in HLA regions were well genotyped. A lower rate of low-responsiveness was observed in the 20 μg group. Rs3135338 GG and rs9277554 TT genotype showed stronger associations with low responsiveness ( P  < 0.05). The combination of 10 μg vaccine with the risk genotypes was independently associated with remarkably increased risk of low-responsiveness to hepatitis B vaccines ( P  < 0.05). HLA SNPs were associated with low-responsiveness to hepatitis B vaccine. For infants with risk genotypes, a 20 μg dose vaccine reduced the risk of low responsiveness. [ABSTRACT FROM AUTHOR]

Background: Psoriasis is an immune-mediated dermatosis with a wide genetic predisposition. The immunogenetic background, specifically interactions between human leukocyte antigen (HLA) class I ligands and killer-cell immunoglobulin-like receptor (KIRs), have functional significance in modulating natural killer (NK) cells and can influence susceptibility and response to biological therapy.Objective: The main aim of this study was to correlate HLA-A and -B KIR ligands with response to biological therapy in patients with psoriasis.Methods: HLA-A and -B polymorphisms were determined in 48 patients (35 males and 13 females), with a mean of 22 years of disease (range 8-55). All patients were treated with biological therapy (adalimumab, etanercept, infliximab, or ustekinumab) for at least 6 months.Results: This study identifies, with statistical significance, the presence of at least one ligand HLA-A Bw4-80I in the “poor-responder” population (patients who needed two or more biologics) compared with the “responder” population (patients with good response after a single biological drug) (47.62 vs. 11.11%; p = 0.006) as well as in “non-responders to etanercept” compared with “responders to etanercept” (52.63 vs. 5%; p = 0.001).Conclusion: Our preliminary results suggest that at least one ligand HLA-A Bw4-80I could be associated with “difficult-to-treat” psoriasis and that this ligand may reduce the probability of response to etanercept, producing more tumor necrosis factor (TNF)-α and neutralizing NK activity through a predominance of activating KIR. The ab initio identification of genetic markers of response to biologic therapy could improve the efficacy and economic impact of these agents. [ABSTRACT FROM AUTHOR]

Class I and class II HLA proteins, respectively, have been associated with subsets of V(D)J usage resulting from recombination of the T-cell receptor (TCR) genes. Additionally, particular HLA alleles, in combination with dominant TCR V(D)J recombinations, have been associated with several autoimmune diseases. The recovery of TCR recombination reads from tumor specimen exome files has allowed rapid and extensive assessments of V(D)J usage, likely for cancer resident T-cells, across relatively large cancer datasets. The results from this approach, in this report, have permitted an extensive alignment of TCR-β VDJ usage and HLA class I and II alleles. Results indicate the correlation of both better and worse cancer survival rates with particular TCR-β, V and J usage-HLA allele combinations, with differences in median survival times ranging from 7 to 130 months, depending on the cancer and the specific TCR-β V and J usage/HLA class allele combination. [ABSTRACT FROM AUTHOR]

Immunogenicity is a major concern in drug development as anti-drug antibodies in many cases affect both patient safety and drug efficacy. Another concern is often the limited half-life of drugs, which can be altered by different chemical modifications, like acylation with fatty acids. However, acylation with fatty acids has been shown in some cases to modulate T cell activation. Therefore, to understand the role of acylation with fatty acids on immunogenicity we tested three immunogenic non-acylated peptides and 14 of their acylated analogues for binding to 26 common HLA class II alleles, and their ability to activate T cells in an ex vivo T cell assay. Changes in binding affinity associated with acylation with fatty acids were typically modest, though a significant decrease was observed for influenza HA acylated with a stearic acid, and affinities for DQ alleles were consistently increased. Importantly, we showed that for all three immunogenic peptides acylation with fatty acids decreased their capacity to activate T cells, a trend particularly evident with longer fatty acids typically positioned within the peptide HLA class II binding core region, or when closer to the C-terminus. With these results we have demonstrated that acylation with fatty acids of immunogenic peptides can lower their stimulatory capacity, which could be important knowledge for drug design and immunogenicity mitigation. [ABSTRACT FROM AUTHOR]

Background: Several recent studies in patients with idiopathic membranous nephropathy (iMN) from Western and Asian counties showed that some single nucleotide polymorphisms (SNPs) within the PLA2R1 and HLA-DQA1 genes are significantly associated with iMN. However, there is only 1 report on analysis of PLA2R1 and HLA regions in Japanese patients with iMN.Methods: A total of 58 patients with iMN, 26 patients with secondary MN (sMN), and 50 patients with other diseases were enrolled. All patients were Japanese. We selected 6 SNPs within PLA2R1 and 1 SNP within HLA-DQA1, which were significantly associated with iMN in reported white European cohorts, and sequenced these exons using genomic DNA prepared from peripheral mononuclear cells from each patient. We then analyzed differences in PLA2R1 and HLA-DQA1 sequence variants among the 3 groups.Results: Genotypic and allelic frequency distributions for 3 out of 6 SNPs within PLA2R1, rs3749117, rs35771982, and rs2715918 were significantly different between the iMN and control groups. Allelic frequency distributions for SNP rs2187668 within HLA-DQA1 were significantly different between the iMN and control groups. There were no correlations between PLA2R1 and HLA-DQA1 sequence variants and clinical parameters in patients with iMN. There were no significant differences in genotypic or allelic frequency distributions for examined SNPs between the sMN and control groups.Conclusions: There are some differences in PLA2R1 SNP distributions between previously reported cohorts from other countries and our Japanese cohort of patients with iMN, while there is a significant association between SNP rs35771982 and iMN in most of reported cohorts. [ABSTRACT FROM AUTHOR]

Humanized mice are emerging as an alternative model system to well-established non-human primate (NHP) models for studying human immunodeficiency virus (HIV)-1 biology and pathogenesis. Although both NHP and humanized mice have their own strengths and could never truly reflect the complex human immune system and biology, there are several advantages of using the humanized mice in terms of using primary HIV-1 for infection instead of simian immunodeficiency virus or chimera simian/HIV. Several different types of humanized mice have been developed with varying levels of reconstitution of human CD45+ cells. In this study, we utilized humanized Rag1KO. IL2RγcKO.NOD mice expressing HLA class II (DR4) molecule (DRAG mice) infused with HLA-matched hematopoietic stem cells from umbilical cord blood to study early events after HIV-1 infection, since the mucosal tissues of these mice are highly enriched for human lymphocytes and express the receptors and coreceptors needed for HIV-1 entry. We examined the various tissues on days 4, 7, 14, and 21 after an intravaginal administration of a single dose of purified primary HIV-1. Plasma HIV-1 RNA was detected as early as day 7, with 100% of the animals becoming plasma RNA positive by day 21 post-infection. Single cells were isolated from lymph nodes, bone marrow, spleen, gut, female reproductive tissue, and brain and analyzed for gag RNA and strong stop DNA by quantitative (RT)-PCR. Our data demonstrated the presence of HIV-1 viral RNA and DNA in all of the tissues examined and that the virus was replication competent and spread rapidly. Bone marrow, gut, and lymph nodes were viral RNA positive by day 4 post-infection, while other tissues and plasma became positive typically between 7 and 14 days post-infection. Interestingly, the brain was the last tissue to become HIV-1 viral RNA and DNA positive by day 21 post-infection. These data support the notion that humanized DRAG mice could serve as an excellent model for studying the trafficking of HIV-1 to the various tissues, identification of cells harboring the virus, and thus could serve as a model system for HIV-1 pathogenesis and reservoir studies. [ABSTRACT FROM AUTHOR]

Introduction Umbilical Cord Blood Units (UCBU) for transplantation, are a therapeutic possibility for patients with a wide range of oncohaematological diseases and other immunologic disorders. The search of compatible donors for bone marrow transplantation is increasingly difficult for patients of mixed ethnicity. The aim of this work was determine the HLA frequency of candidates for transplantation without compatible UCBU at the National Center of from Blood Transfusion (NCBT) – Mexico. Material and methods A retrospective analysis of candidates to transplant without compatible UCBU was performed in the archives from 2003 to 2016 at the NCBT. HLA class I and II genotyping of candidates was performed by medium resolution methods: Sequence Specific Primer and/or Specific Sequence Oligonucleotide. HLA frequencies were obtained by including individuals without any particular bias to a phenotype and strict statistical and genetic analysis of populations were done. The database in www.allelefrequencies.net was used in order to identify the ethnic origin of the most frequent alleles. Results Three hundred and sixty-four candidates without compatible UCBU for transplantation were identified. The most frequent haplotype HLA I and II were: HLA-A*02/02, 02/24, 24/24, 02/68, 01/24 and 24/68; HLA-B*39/39, 35/51, 44/44, 44/40, 35/40 and 35/35; HLA-DRB1*04/04, 13/07, 04/13, 13/13 and 03/11. The ethnic origins of the analyzed data were represented in most cases by Amerindians, Caucasics, Orientals, Asians, Arabs and Africans. Conclusion This work shows the existence of a broad genetic diversity of candidates for transplantation with UCBU, making it difficult to find compatible units considering donors only from the capital. [ABSTRACT FROM AUTHOR]

Rheumatoid arthritis (RA) is a chronic auto-immune disease primarily targeting the joints. Approximately 1% of the population is affected by RA, and despite the improvements in therapeutic interventions, elucidation of the disease pathogenesis is still in its infancy. RA patients can be subdivided on basis of the presence of autoantibodies, especially anti-citrullinated protein antibodies (ACPA). ACPA and ACPA disease most likely differ in aetiology, as different genetic and environmental risk factors are associated with these two disease entities. For ACPA RA disease, the genetic factors associating with disease mainly comprised of human leukocyte antigen (HLA) class II molecules. The predisposing HLA-DR alleles have been depicted as the 'HLA Shared Epitope (SE) alleles', as these alleles encode a similar sequence, the shared epitope sequence, within the beta chain of the HLA-DR molecule. In addition to the involvement of the HLA-SE alleles in the development of ACPA RA disease, other HLA-DR molecules have been shown to confer protection against this disease entity. The protective HLA molecules have, instead of the SE-motif, a different but shared sequence at the same location in the beta chain of HLA-DR molecules, consisting of the amino acid residues DERAA. The possible contributions of the predisposing and protective HLA molecules in association with ACPA-positive RA are discussed in this review. [ABSTRACT FROM AUTHOR]

Goodpasture's disease is closely associated with HLA, particularly DRB1*1501. Other susceptible or protective HLA alleles are not clearly elucidated. The presentation models of epitopes by susceptible HLA alleles are also unclear. We genotyped 140 Chinese patients and 599 controls for four-digit HLA II genes, and extracted the encoding sequences from the IMGT/ HLA database. T-cell epitopes of α3( IV) NC1 were predicted and the structures of DR molecule-peptide- T-cell receptor were constructed. We confirmed DRB1*1501 ( OR = 4·6, P = 5·7 × 10−28) to be a risk allele for Goodpasture's disease. Arginine at position 13 ( ARG13) ( OR = 4·0, P = 1·0 × 10−17) and proline at position 11 ( PRO11) ( OR = 4·0, P = 2·0 × 10−17) on DR β1, encoded by DRB1*1501, were associated with disease susceptibility. α134-148 ( HGWISLWKGFSFIMF) was predicted as a T-cell epitope presented by DRB1*1501. Isoleucine137, tryptophan140, glycine142, phenylalanine143 and phenylalanine145, were presented in peptide-binding pockets 1, 4, 6, 7 and 9 of DR2b, respectively. ARG13 in pocket 4 interacts with tryptophan140 and forms a hydrogen bond. In conclusion, we propose a mechanism for DRB1*1501 susceptibility for Goodpasture's disease through encoding ARG13 and PRO11 on MHC- DR β1 chain and presenting T-cell epitope, α134-148, with five critical residues. [ABSTRACT FROM AUTHOR]

We explored the association between the HLA-II gene polymorphisms and the occurrence of leukemia. For this study, we selected 53 patients with leukemia treated at Zhongnan Hospital of Wuhan University from February 2014 to September 2015 and 46 healthy patients as the control group. We used polymerase chain reaction with sequence specific primers for DNA typing which was carried out to analyze the patients HLA-A/B gene polymorphism. We also used enzyme-linked immunosorbent assay and western blotting method to measure the protein expression of different genotypes and activity. Compared to the control group, HLA-A04, B08 gene frequencies were significantly lower than those of HLA-A04, B08 gene frequencies of the observation group; results were statistically significant (χ2=16.28, P<0.05; χ2=16.47, P<0.05). However, in the control group, the frequency of HLA-A09 gene was significantly higher than that of the observation group; there was a significant difference between the two groups (χ2=15.28, P<0.05). Through the measurement of the protein expression levels of the different genotypes in the control group and the observation group, it was found that in the observation group, HLA-A04, B08 protein contents (4.6 and 3.2 μg/l) were significantly higher than those of the control group (0.13 and 0.1 μg/l). While the control group HLA-A09 genotype protein content (3.7 μg/l) was significantly higher than that of the observation group (0.2 μg/l); there were significant differences between both (P<0.05). Therefore, there is a significant correlation between HLA-II gene polymorphism and leukemia that is higher than HLA-A04 and B08 gene frequency and can help promote the occurrence of leukemia. The higher frequency of HLA-A09 gene can help to suppress the occurrence of leukemia. [ABSTRACT FROM AUTHOR]

Genetic and environmental factors are responsible for differences in the prevalence of some diseases across countries. Human leukocyte antigen (HLA) allele frequencies in North African populations show some differences in their distribution compared to Europeans, Mediterraneans, and sub-Saharans, and some specific alleles and haplotypes could be clinically relevant. Celiac disease (CD) has been fast increasing in prevalence in North Africa; but few immunogenetic data are available for this area, in which a high prevalence of the disease has been described. In this report, we assess and discuss results of HLA class II (HLA-DQA1/DQB1/DRB1) typing in Moroccan patients with CD and compare them with a control population from Morocco--genetically well characterized--and with other North African, Mediterranean, and European populations. The classical HLA-DQ associations were confirmed in Moroccans with CD. The high frequency of DQ2.5 homozygosity (45.2%) found in Moroccans with CD was noteworthy as compared with other populations (23%--32%). The genetic risk gradient for CD, identified by previous studies, has been confirmed in Moroccans with some differences, mainly concerning DQ8 genotypes. This study provides the immunogenetic framework of CD in Moroccans and confirms the need to learn more about associations with additional HLA and non-HLA genetic factors. [ABSTRACT FROM AUTHOR]

Background and Objectives Alloimmune antibodies against red-blood-cell ( RBC) antigens induced in susceptible individuals (responders) by transfusion, pregnancy or transplantation may have serious clinical consequences. The aim of this study was to investigate association of alloimmunization against selected RBC antigens with HLA-Class II. Materials and Methods A total of 230 responders (106 monoresponders and 124 multiresponders) were enrolled into the study. HLA- DRB1 and HLA- DQB1 variants were determined by PCR- SSO and their frequencies compared between the patients (patient subgroups) and 375 ethnically and regionally matched controls. Results Development of multiple RBC antibodies was associated with HLA- DRB1*15 and HLA- DQB1*06 allelic groups in the patients, with the relationship being particularly apparent in those with anti-C+D antibodies. Furthermore, DRB1*13 and DQB1*06 were more frequent in multiresponders with anti-E+c antibodies and DRB1*03 and DQB1*02 in those with anti-E+Cw. Conclusion For the first time, we confirmed the association of HLA- DRB1*15 with RBC antibody multiresponder status and found HLA-Class II associations for three frequent RBC antibody combinations. Our data support the concept that HLA restriction plays an important role in the response to RBC alloantigens. [ABSTRACT FROM AUTHOR]

Background & aims Genetic factors in class II human leukocyte antigen ( HLA ) have been reported to be associated with inter-individual variation in hepatitis B virus (HBV) vaccine response. However, the mechanism underlying the associations remains elusive. In particular, the broad linkage disequilibrium in HLA region complicates the localization of the independent effects of genetic variants. Thus, the present study aimed to identify the most probable causal variations in class II HLA loci involved in the immune response to HBV vaccine. Methods We performed a case-control study to assess whether HLA-DRB1 , - DQB1 , and -DPB1 4-digit alleles were associated with the response to primary HBV vaccination in 574 healthy Japanese students. To identify causative variants, we next assessed independently associated amino acid variants in these loci using conditional logistic regression analysis. Furthermore, to clarify the functional effects of these variants on HLA proteins, we performed computational structural studies. Results HLA-DRB1 ∗ 01:01 , HLA-DRB1 ∗ 08:03 , HLA-DQB1 ∗ 05:01 , and HLA-DPB1 ∗ 04:02 were significantly associated with sufficient response, whereas HLA-DPB1 ∗ 05:01 was associated with poor response. We then identified amino acids independently associated with sufficient response, namely, leucine at position 26 of HLA-DRβ1 and glycine-glycine-proline-methionine at positions 84–87 of HLA-DPβ1. These amino acids were located in antigen-binding pocket 4 of HLA-DR and pocket 1 of HLA-DP, respectively, which are important structures for selective binding of antigenic peptides. In addition, the detected variations in HLA-DP protein were responsible for the differences in the electrostatic potentials of the pocket, which can explain in part the sufficient/poor vaccine responses. Conclusion HLA-DRβ1 position 26 and HLA-DPβ1 positions 84–87 are independently associated with anti-HBs production against HBV vaccine. Our results suggest that HBsAg presentation through these HLA pocket structures plays an important role in the inter-individual variability of HBV vaccination. [ABSTRACT FROM AUTHOR]

Lupus nephritis (LN) is a disease with a poor prognosis. The association between LN and the Human leukocyte antigen (HLA) genes has never been studied on a Moroccan population. The aim of this work was to evaluate the distribution of the HLA class II alleles in patients with LN and to determine susceptible and protective HLA alleles/haplotypes in LN. The association between these alleles, disease severity of LN, and age at onset were also investigated. Seventy-five patients with LN were compared with 169 healthy unrelated controls. HLA class II alleles typing was performed by polymerase chain reaction-sequence-specific primers (PCR-SSP). A significant increase of HLA-DRB1*15 allele frequency (p= 0.001) and a significant decrease of the HLA-DRB1*04 allele (p= 0.04) were observed in LN patients. The frequency of HLA-DRB1*15-DQB1*06 haplotype (p= 0.003) was increased in the patients while that of HLA-DRB1*04-DQB1*03 (p= 0.027) was decreased. A significant increase of HLA-DRB1*15 allele frequency (p= 0.0001) and HLA-DRB1*15-DQB1*06 haplotype (p= 0.002) was observed in patients with class IV LN. In the Moroccan population we demonstrated the positive association of HLA class II alleles and haplotypes with LN and with a severe form of nephritis. HLA-DRB1*15 allele does not determine the age of disease onset in LN. [ABSTRACT FROM PUBLISHER]

Human leucocyte antigen ( HLA) genes play a central role in response to pathogens and in autoimmunity. Research to understand the effects of HLA genes on health has been limited because HLA genotyping protocols are labour intensive and expensive. Recently, algorithms to impute HLA genotype data using genome-wide association study ( GWAS) data have been published. However, imputation accuracy for most of these algorithms was based primarily on training data sets of European ancestry individuals. We considered performance of two HLA-dedicated imputation algorithms - SNP2 HLA and HIBAG - in a multiracial population of n = 1587 women with HLA genotyping data by gold standard methods. We first compared accuracy - defined as the percentage of correctly predicted alleles - of HLA-B and HLA-C imputation using SNP2 HLA and HIBAG using a breakdown of the data set into an 80% training group and a 20% testing group. Estimates of accuracy for HIBAG were either the same or better than those for SNP2 HLA. We then conducted a more thorough test of HIBAG imputation accuracy using five independent 10-fold cross-validation procedures with delineation of ancestry groups using ancestry informative markers. Overall accuracy for HIBAG was 89%. Accuracy by HLA gene was 93% for HLA-A, 84% for HLA-B, 94% for HLA-C, 83% for HLA- DQA1, 91% for HLA- DQB1 and 88% for HLA- DRB1. Accuracy was highest in the African ancestry group (the largest group) and lowest in the Hispanic group (the smallest group). Despite suboptimal imputation accuracy for some HLA gene/ancestry group combinations, the HIBAG algorithm has the advantage of providing posterior estimates of accuracy which enable the investigator to analyse subsets of the population with high predicted (e.g. >95%) imputation accuracy. [ABSTRACT FROM AUTHOR]

It has been difficult to translate promising results from DNA vaccination in mice to larger animals and humans. Previously, DNA vaccines encoding proteins that target Ag toMHCclass II (MHC-II) molecules on APCs have been shown to induce rapid, enhanced, and long-lasting Ag-specific Ab titers in mice. In this study, we describe two novel DNAvaccines that as proteins target HLA class II (HLA-II) molecules. These vaccine proteins cross-react with MHC-II molecules in several species of larger mammals. When tested in ferrets and pigs, a single DNA delivery with low doses of the HLA-II-targeted vaccines resulted in rapid and increased Ab responses. Importantly, painless intradermal jet delivery of DNA was as effective as delivery by needle injection followed by electroporation. As an indication that the vaccines could also be useful for human application, HLA-II-targeted vaccine proteins were found to increase human CD4+ T cell responses by a factor of ×103 in vitro. Thus, targeting of Ag to MHC-II molecules may represent an attractive strategy for increasing efficacy of DNA vaccines in larger animals and humans. [ABSTRACT FROM AUTHOR]

Rheumatoid arthritis ( RA) is a complex multifactorial autoimmune disease characterized by inflammatory arthritis. The precise etiology and pathogenesis of RA remains elusive but evidence points towards stochastic interactions between genetic and environmental factors. This study investigated the distribution of human leucocyte antigen ( HLA)- DRB1/ DQB1 alleles in South Indian patients with rheumatoid arthritis ( RA) and their influence on RA susceptibility and clinical phenotype. Low resolution HLA-DRB1 and - DQB1 typing was performed in 271 RA patients and 233 healthy controls by polymerase chain reaction ( PCR) using sequence-specific primers ( SSP). HLA-DRB1*10 was found to be more frequent in patients ( Pc = 0.004, OR = 2.23, 95% CI = 1.5-3.34) than controls. This difference persisted in RF positive ( Pc = 9 × 10−6, OR = 2.45, 95% CI = 1.62-3.74), ACPA positive ( Pc = 0.007, OR = 2.10, 95% CI = 1.35-3.29), ACPA negative ( Pc = 0.001, OR = 2.45, 95% CI = 1.50-3.97) and both RF and ACPA positive subgroup of patients ( Pc = 0.003, OR = 2.22, 95% CI = 1.41-3.51). On the contrary, the HLA-DRB1*13 ( Pc = 0.01, OR = 0.43, 95% CI = 0.25-0.73) and HLA-DRB1*14 ( Pc = 0.003, OR = 0.43, 95% CI = 0.26-0.69) alleles were over-represented in controls than patients. Further, distribution of the prominent Caucasian RA risk allele DRB1*04 did not differ between patients and controls in our study population. We did not find any association between DQB1 alleles and RA susceptibility or autoantibody status. The haplotypes DQB1*05- DRB1*10 ( P = 6.8 × 10−6, OR = 2.46, 95% CI = 1.63-3.79) and DQB1*06- DRB1*15 ( P = 0.03, OR = 1.41, 95% CI = 1.02-1.96) were more frequent in patients while DQB1*05- DRB1*14 ( P = 8.4 × 10−4, OR = 0.44, 95% CI = 0.26-0.74) and DQB1*06- DRB1*13 ( P = 9.5 × 10−4, OR = 0.40, 95% CI = 0.21-0.72) were higher in controls. To conclude, HLA-DRB1*10 is associated with RA while HLA-DRB1*13 and HLA-DRB1*14 alleles confer protection in south Indian Tamils. [ABSTRACT FROM AUTHOR]

Rare are the family studies that include siblings affected by pemphigus vulgaris (PV) and in whom HLA class II alleles are related. HLA-DR and - DQ genotyping and profiling of antibodies against desmogleins (Dsg) 1 and Dsg3 were performed in ten members of a family including monozygotic twins affected by PV. The twin sisters were heterozygotes; they presented the haplotypes most commonly associated with increased susceptibility to PV ( DRB1 ∗04:02 -DQA1 ∗03:01 -DQB1 ∗03:02 and DRB1 ∗14:04 -DQA1 ∗01:01 -DQB1 ∗05:03). Their parents and five siblings had only one or none of these two haplotypes in combination with the alleles or haplotypes associated with resistance to PV ( DRB1 ∗07:01 -DQA1 ∗02:01 -DQB1 ∗02:02 and DRB1 ∗13:01 -DQA1∗ 01:03- DQB1 ∗06:03). Only the monozygotic twins presented IgG antibodies against both Dsg1 and Dsg3. According to our knowledge based on a review of published literature on the topic, this is the first report of PV affecting monozygotic twins. [ABSTRACT FROM AUTHOR]

Respiratory syncytial virus (RSV) is a leading cause of lower respiratory tract disease, which causes high rates of morbidity and mortality in infants and the elderly. Models of human RSV pulmonary disease are needed to better understand RSV pathogenesis and to assess the efficacy of RSV vaccines. We assessed the RSV-specific human innate, humoral, and cellular immune responses in humanized mice (mice with a human immune system [HIS mice]) with functional human CD4+ T and B cells. These mice were generated by introduction of HLA class II genes, various human cytokines, and human B cell activation factor into immunodeficient NOD scid gamma (NSG) mice by the use of an adeno-associated virus vector, followed by engraftment of human hematopoietic stem cells. During the first 3 days of infection, HIS mice lost more weight and cleared RSV faster than NSG mice. Human chemokine (C-C motif) ligand 3 (CCL3) and human interleukin-1β (IL-1β) expression was detected in the RSV-infected HIS mice. The pathological features induced by RSV infection in HIS mice included peribronchiolar inflammation, neutrophil predominance in the bronchioalveolar lavage fluid, and enhanced airway mucus production. Human anti-RSV IgG and RSVneutralizing antibodies were detected in serum and human anti-RSV mucosal IgA was detected in bronchioalveolar lavage fluid for up to 6 weeks. RSV infection induced an RSV-specific human gamma interferon response in HIS mouse splenocytes. These results indicate that human immune cells can induce features of RSV lung disease, including mucus hyperplasia, in murine lungs and that HIS mice can be used to elicit human anti-RSV humoral and cellular immunity. [ABSTRACT FROM AUTHOR]

Background: We previously demonstrated that the HLA class II transactivator CIITA inhibits HIV-1 replication in T cells by competing with the viral transactivator Tat for the binding to Cyclin T1 subunit of the P-TEFb complex. Here, we analyzed the anti-viral function of CIITA in myeloid cells, another relevant HIV-1 target cell type. We sinvestigated clones of the U937 promonocytic cell line, either permissive (Plus) or non-permissive (Minus) to HIV-1 replication. This different phenotype has been associated with the expression of TRIM22 in U937 Minus but not in Plus cells.Methods: U937 Plus cells stably expressing CIITA were generated and HLA-II positive clones were selected by cell sorting and cloning. HLA and CIITA proteins were analyzed by cytofluorometry and western blotting, respectively. HLA-II DR and CIITA mRNAs were quantified by qRT-PCR. Tat-dependent transactivation was assessed by performing the HIV-1 LTR luciferase gene reporter assay. Cells were infected with HIV-1 and viral replication was evaluated by measuring the RT activity in culture supernatants.Results: CIITA was expressed only in HLA-II-positive U937 Minus cells, and this was strictly correlated with inhibition of Tat-dependent HIV-1 LTR transactivation in Minus but not in Plus cells. Overexpression of CIITA in Plus cells restored the suppression of Tat transactivation, confirming the inhibitory role of CIITA. Importantly, HIV-1 replication was significantly reduced in Plus-CIITA cells with respect to Plus parental cells. This effect was independent of TRIM22 as CIITA did not induce TRIM22 expression in Plus-CIITA cells.Conclusions: U937 Plus and Minus cells represent an interesting model to study the role of CIITA in HIV-1 restriction in the monocytic/macrophage cell lineage. The differential expression of CIITA in CIITA-negative Plus and CIITA-positive Minus cells correlated with their capacity to support or not HIV-1 replication, respectively. In Minus cells CIITA targeted the viral transactivator Tat to inhibit HIV-1 replication. The generation of Plus-CIITA cells was instrumental to demonstrate the specific contribution of CIITA in terms of inhibition of Tat activity and HIV-1 restriction, independently from other cellular factors, including TRIM22. Thus, CIITA acts as a general restriction factor against HIV-1 not only in T cells but also in myeloid cells. [ABSTRACT FROM AUTHOR]

Background Previous studies have revealed different human leukocyte antigen (HLA) associations in multiple sclerosis (MS) and neuromyelitis optica (NMO), further discriminating these two demyelinating pathological conditions. In worldwide analyses, NMO and opticospinal MS are represented at higher proportions among demyelinating conditions in African, East-Asian and Latin American populations. There are currently no data regarding the prevalence of NMO in Middle East Muslims. The population in Israel is diverse in many ways, and includes subpopulations, based on religion and ethnicity; some exhibit genetic homogeneity. In Israel, the incidence of MS is lower in the Muslim population than the Jewish population and Muslims carry different allele frequency distribution of HLA haplotypes. Objective To evaluate the occurrence of anti-AQP4 seropositivity in the Israeli Muslim population among patients with central nervous system (CNS) demyelinating conditions; and to identify the HLA DR and DQ profiles of Muslim Arab Israeli patients with NMO spectrum of diseases (NMOSD). Methods The prevalence of anti-AQP4 seropositivity was analyzed in 342 samples, obtained from patients with various CNS demyelinating conditions and in a validation set of 310 samples. HLA class II alleles (HLA-DRB1 and DQB1) were examined in DNA samples from 35 Israeli Muslim Arabs NMO patients and compared to available data from 74 Israeli Muslim controls. Results Our data reveal a significantly increased prevalence of anti-AQP4 seropositivity, indicative of NMOSD, in Muslim Arab Israeli patients with initial diagnosis of a CNS demyelinating syndrome. In this population, there was a positive association with the HLA-DRB1*04:04 and HLA-DRB1*10:01 alleles (p = 0.03), and a strong negative association with the HLA-DRB1*07 and HLA-DQB1*02:02 alleles (p = 0.003, p = 0.002). Conclusions Our findings indicate a possibly increased prevalence of NMOSD in Muslim Arabs in Israel with distinct (positive and negative) HLA associations. Further studies in patients with similar genetic backgrounds worldwide could help to confirm our findings and identify more genetic susceptibility factors for NMO, contributing to our general understanding of the pathogenesis of NMOSD. [ABSTRACT FROM AUTHOR]

Background Multiple sclerosis (MS) is an autoimmune demyelinating disease affecting mostly young adult females with multifactorial etiology. Recent studies suggested that adequate vitamin D levels may lower the risk of developing MS. Objectives Our aim was to explore the relationship between vitamin D receptor (VDR) polymorphism, HLA-DR locus genotype, and serum vitamins D and A levels in the Lebanese population. Methods Fifty MS patients were recruited for this study. The control group consisted of 48 healthy and 51 patients with other neurological disorders (non-MS). Biochemical analysis included serum 25 hydroxyvitamin D (25OHD) and vitamin A. Molecular analysis targeted VDR genotypes ( ApaI , TaqI and BsmI ) and low resolution HLA typing for DRB1 locus. Results Healthy and non-MS groups had comparable parameters and were combined into one control group. No significant differences were found between MS and control groups for VDR genotypes. The frequency of HLA-DRB1*15 was significantly higher in MS patients (22%) compared to controls (8%) (p = 0.018). Odds ratio for MS in the presence of DRB1*15 allele was 3.21 (p = 0.018). Cosegregation with A ( ApaI ) and b ( BsmI ) alleles did not influence the risk for MS. 25OHD levels were significantly higher in MS patients compared to controls (p = 0.002), due to more frequent oral supplementation (p = 0.005). Vitamin A levels were comparable between the two groups. When all parameters were included in a logistic regression model adjusted for supplementation, only HLA-DRB1*15 (OR = 3.42; p = 0.027) contributed significantly to MS risk. Conclusion There was no association between serum vitamin D or A or VDR genotypes and MS. HLA-DRB1*15 was the major factor imposing more than 3 folds greater risk for developing MS among Lebanese. [ABSTRACT FROM AUTHOR]

Background: Little is known about the associations between human leukocyte antigens (HLAs) and food allergies. Our aim was to analyze the associations between the HLA class II polymorphism and food allergy using bioinformatics. Methods: A two-step algorithm was developed which mimics the food allergen processing in the human body. In the first step, the allergen is digested by pepsin, trypsin and chymotrypsin. In the second step, the digested fragments bind to the most frequent 12 HLA-DRB1 and 5 HLA-DQ alleles, and the binding affinities are predicted. Results: The algorithm was applied to 13 well-known milk and egg allergens. The predicted HLA binders were compared to known T-cell and IgE epitopes originating from the same allergens, and 77% of them were found to overlap. We found that the peptides generated from milk allergens bind to DRB1 * 01: 01, DQ7 and DQ8 but not to DRB1 * 03: 01, DRB1 * 04: 04, DRB1 * 12: 01 and DRB1 * 15: 01. The peptides generated from egg allergens bind to DRB1 * 01: 01, DQ4, DQ7 and DQ8 but not to DRB1 * 03: 01, DRB1 * 04: 04 and DRB1 * 12: 01. They bind to all the DQs studied. The alleles that bind to allergen peptides could be considered as susceptible to the particular allergy and the nonbinding alleles as protective. Conclusions: The alleles DRB1 * 01: 01, DQ7 and DQ8 are considered as susceptible to cow's milk allergy and DRB1 * 03: 01, DRB1 * 04: 04, DRB1 * 12: 01 and DRB1 * 15: 01 as protective. The alleles DRB1 * 01: 01, DQ4, DQ7 and DQ8 are considered as susceptible to egg allergy and DRB1 * 03: 01, DRB1 * 04: 04 and DRB1 * 12: 01 as protective. Protective DQs against egg allergy were not revealed in this study. [ABSTRACT FROM AUTHOR]

The HLA class II genes are susceptibility genes for autoimmune endocrine diseases; however, scarce data are available pertaining to the determinants of genetic susceptibility to polyglandular autoimmunity (PGA). A total of 300 consecutive and unselected patients with either PGA or monoglandular autoimmune thyroid disease (AITD) and 100 healthy control subjects were genotyped for the HLA class II DRB1, -DQA1, and -DQB1 alleles. Compared to patients with AITD and controls, the HLA-DRB1 * 03 (pc = 0.001), * 04 (pc < 0.001), -DQA1 * 03 (pc < 0.001), and -DQB1 * 02 (pc = 0.001) alleles were increased in patients with PGA. When dividing patients with Hashimoto's thyroiditis (HT) into those with PGA (PGA-HT) vs. those with HT as monoglandular disease, significant differences for the DRB1 * 03 (pc = 0.001) and DQA1 * 03 (pc = 0.001) alleles were observed. In contrast, the DQB1 * 02 allele was more prevalent in PGA patients with Graves' disease (PGA-GD) vs. those with monoglandular GD (pc = 0.002). The HLA-DRB1 * 15 (pc = 0.001), -DQA1 * 01 (pc = 0.001), -DQB1 * 05 (pc = 0.002) and -DQB1 * 06 (pc = 0.002) alleles were significantly less present in PGA compared to monoglandular AITD and controls, thus indicating protective alleles. The HLA class II alleles differentiate between mono- and polyglandular autoimmunity in patients with autoimmune thyroid disease. [ABSTRACT FROM AUTHOR]

To develop a new therapeutic monoclonal Antibody (mAb) for Hodgkin lymphoma (HL), we immunized a BALB/c mouse with live HL cell lines, alternating between two HL cell lines. After hybridization, we screened the hybridoma clones by assessing direct cytotoxicity against a HL cell line not used for immunization. We developed this strategy for establishing mAb to reduce the risk of obtaining clonotypic mAb specific for single HL cell line. A newly established mouse anti-human mAb (4713) triggered cytoskeleton-dependent, but complement- and caspase-independent, cell death in HL cell lines, Burkitt lymphoma cell lines, and advanced adult T-cell leukemia cell lines. Intravenous injection of mAb 4713 in tumor-bearing SCID mice improved survival significantly. mAb 4713 was revealed to be a mouse anti-human pan-HLA class II mAb. Treatment with this mAb induced the formation of large pores on the surface of target lymphoma cells within 30 min. This finding suggests that the cell death process induced by this anti-pan HLA-class II mAb may involve the same death signals stimulated by a cytolytic anti-pan MHC class I mAb that also induces large pore formation. This multifaceted study supports the therapeutic potential of mAb 4713 for various forms of lymphoma. [ABSTRACT FROM AUTHOR]

Activation of CD4+ T cells requires the recognition of peptides that are presented by HLA class II molecules and can be assessed experimentally using the ELISpot assay. However, even given an individual’s HLA class II genotype, identifying which class II molecule is responsible for a positive ELISpot response to a given peptide is not trivial. The two main difficulties are the number of HLA class II molecules that can potentially be formed in a single individual (3–14) and the lack of clear peptide binding motifs for class II molecules. Here, we present a Bayesian framework to interpret ELISpot data (BIITE: Bayesian Immunogenicity Inference Tool for ELISpot); specifically BIITE identifies which HLA-II:peptide combination(s) are immunogenic based on cohort ELISpot data. We apply BIITE to two ELISpot datasets and explore the expected performance using simulations. We show this method can reach high accuracies, depending on the cohort size and the success rate of the ELISpot assay within the cohort. [ABSTRACT FROM AUTHOR]

Background: Staphylococcus aureus can cause life-threatening infections. Human susceptibility to S. aureus infection may be influenced by host genetic variation.Methods: A genome-wide association study (GWAS) in a large health plan-based cohort included biologic specimens from 4701 culture-confirmed S. aureus cases and 45 344 matched controls; 584 535 single-nucleotide polymorphisms (SNPs) were genotyped on an array specific to individuals of European ancestry. Coverage was increased by imputation of >25 million common SNPs, using the 1000 Genomes Reference panel. In addition, human leukocyte antigen (HLA) serotypes were also imputed.Results: Logistic regression analysis, performed under the assumption of an additive genetic model, revealed several imputed SNPs (eg, rs115231074: odds ratio [OR], 1.22 [P = 1.3 × 10(-10)]; rs35079132: OR, 1.24 [P = 3.8 × 10(-8)]) achieving genome-wide significance on chromosome 6 in the HLA class II region. One adjacent genotyped SNP was nearly genome-wide significant (rs4321864: OR, 1.13; P = 8.8 × 10(-8)). These polymorphisms are located near the genes encoding HLA-DRA and HLA-DRB1. Results of further logistic regression analysis, in which the most significant GWAS SNPs were conditioned on HLA-DRB1*04 serotype, showed additional support for the strength of association between HLA class II genetic variants and S. aureus infection.Conclusions: Our study results are the first reported evidence of human genetic susceptibility to S. aureus infection. [ABSTRACT FROM AUTHOR]

In 40% of cases of classical Hodgkin lymphoma (cHL), Epstein-Barr virus (EBV) latency-II antigens [EBV nuclear antigen 1 (EBNA1)/latent membrane protein (LMP)1/LMP2A] are present (EBV+cHL) in the malignant cells and antigen presentation is intact. Previous studies have shown consistently that HLA-A*02 is protective in EBV+cHL, yet its role in disease pathogenesis is unknown. To explore the basis for this observation, gene expression was assessed in 33 cHL nodes. Interestingly, CD8 and LMP2A expression were correlated strongly and, for a given LMP2A level, CD8 was elevated markedly in HLA-A*02- versus HLA-A*02+ EBV+cHL patients, suggesting that LMP2A-specific CD8+ T cell anti-tumoral immunity may be relatively ineffective in HLA-A*02- EBV+cHL. To ascertain the impact of HLA class I on EBV latency antigen-specific immunodominance, we used a stepwise functional T cell approach. In newly diagnosed EBV+cHL, the magnitude of ex-vivo LMP1/2A-specific CD8+ T cell responses was elevated in HLA-A*02+ patients. Furthermore, in a controlled in-vitro assay, LMP2A-specific CD8+ T cells from healthy HLA-A*02 heterozygotes expanded to a greater extent with HLA-A*02-restricted compared to non-HLA-A*02-restricted cell lines. In an extensive analysis of HLA class I-restricted immunity, immunodominant EBNA3A/3B/3C-specific CD8+ T cell responses were stimulated by numerous HLA class I molecules, whereas the subdominant LMP1/2A-specific responses were confined largely to HLA-A*02. Our results demonstrate that HLA-A*02 mediates a modest, but none the less stronger, EBV-specific CD8+ T cell response than non-HLA-A*02 alleles, an effect confined to EBV latency-II antigens. Thus, the protective effect of HLA-A*02 against EBV+cHL is not a surrogate association, but reflects the impact of HLA class I on EBV latency-II antigen-specific CD8+ T cell hierarchies. [ABSTRACT FROM AUTHOR]

Background: Mycobacterium tuberculosis (Mtb) is reported to infect about a third of the world's population but only 10% are thought to develop active tuberculosis (TB) disease. Host immunity regulated by human leukocyte antigens (HLA) is an important determinant of the outcome of the disease. Here we investigate HLA class II gene polymorphisms in susceptibility to TB, and whether particular HLA class II alleles were associated with TB in Uganda.Methods: HIV negative patients with pulmonary TB (n = 43) and genetically related healthy household controls (n = 42) were typed for their HLA II class alleles using polymerase chain reaction sequence specific primer amplification.Results: The HLA-DQB1*03:03 allele was significantly less frequent in patients compared to healthy controls (10% in controls versus 0% in patients, p = 0.003). After correction for multiple comparisons the difference remained significant (p = 0.018).Conclusions: Our results suggest that the HLA-DQB1*03:03 allele may be associated with resistance to TB. [ABSTRACT FROM AUTHOR]

Pemphigus vulgaris (PV) and pemphigus foliaceus (PF) are two severe autoimmune bullous diseases of the mucosae and/or skin associated with autoantibodies directed against desmoglein (Dsg) 3 and/or Dsg1. These two desmosomal cadherins, typifying stratified epithelia, are components of cell adhesion complexes called desmosomes and represent extra-desmosomal adhesion receptors. We herein review the advances in our understanding of the immune response underlying pemphigus, including human leucocyte antigen (HLA) class II-associated genetic susceptibility, characteristics of pathogenic anti-Dsg antibodies, antigenic mapping studies as well as findings about Dsg-specific B and T cells. The pathogenicity of anti-Dsg autoantibodies has been convincingly demonstrated. Disease activity and clinical phenotype correlate with anti-Dsg antibody titers and profile while passive transfer of anti-Dsg IgG from pemphigus patients' results in pemphigus-like lesions in neonatal and adult mice. Finally, adoptive transfer of splenocytes from Dsg3-knockout mice immunized with murine Dsg3 into immunodeficient mice phenotypically recapitulates PV. Although the exact pathogenic mechanisms leading to blister formation have not been fully elucidated, intracellular signaling following antibody binding has been found to be necessary for inducing cell-cell dissociation, at least for PV. These new insights not only highlight the key role of Dsgs in maintenance of tissue homeostasis but are expected to progressively change pemphigus management, paving the way for novel targeted immunologic and pharmacologic therapies. [ABSTRACT FROM AUTHOR]

Misfolded proteins localized in the endoplasmic reticulum are degraded promptly and thus are not transported outside cells. However, misfolded proteins in the endoplasmic reticulum are rescued from protein degradation upon association with major histocompatibility complex (MHC) class II molecules and are transported to the cell surface by MHC class II molecules without being processed to peptides. Studies on the misfolded proteins rescued by MHC class II molecules have revealed that misfolded proteins associated with MHC class II molecules are specific targets for autoantibodies produced in autoimmune diseases. Furthermore, a strong correlation has been observed between autoantibody binding to misfolded proteins associated with MHC class II molecules and the autoimmune disease susceptibility conferred by each MHC class II allele. These new insights into MHC class II molecules suggest that misfolded proteins rescued from protein degradation by MHC class II molecules are recognized as "neo-self" antigens by immune system and are involved in autoimmune diseases as autoantibody targets. [ABSTRACT FROM AUTHOR]

The magnitude of the human antibody response to viral antigens is highly variable. To explore the human genetic contribution to this variability, we performed genome-wide association studies of the immunoglobulin G response to 14 pathogenic viruses in 2,363 immunocompetent adults. Significant associations were observed in the major histocompatibility complex region on chromosome 6 for influenza A virus, Epstein-Barr virus, JC polyomavirus, and Merkel cell polyomavirus. Using local imputation and fine mapping, we identified specific amino acid residues in human leucocyte antigen (HLA) class II proteins as the most probable causal variants underlying these association signals. Common HLA-DRβ1 haplotypes showed virus-specific patterns of humoral-response regulation. We observed an overlap between variants affecting the humoral response to influenza A and EBV and variants previously associated with autoimmune diseases related to these viruses. The results of this study emphasize the central and pathogen-specific role of HLA class II variation in the modulation of humoral immune response to viral antigens in humans. [ABSTRACT FROM AUTHOR]

T-cell responses to the immediate-early 1 (IE-1) protein of human cytomegalovirus (HCMV) are associated with protection from viral disease. Thus, IE-1 is a promising target for immunotherapy. CD8 T-cell responses to IE-1 are generally strong. In contrast, CD4 T-cell responses to IE-1 were described to be comparatively infrequent or undetectable in HCMV carriers, and information on their target epitopes and their function has been limited. To analyze the repertoire of IE-1-specific CD4 T cells, we expanded them from healthy donors with autologous IE-1-expressing mini-Epstein-Barr virus-transformed B-cell lines and established IE-1-specific CD4 T-cell clones. Clones from seven out of seven HCMV-positive donors recognized endogenously processed IE-1 epitopes restricted through HLA-DR, DQ, or DP. Three to seven IE-1 epitopes were recognized per donor. Cumulatively, about 27 different HLA/peptide class II complexes were recognized by 117 IE-1-specific clones. Our results suggest that a highly diversified repertoire of IE-1-specific CD4 T cells targeting multiple epitopes is usually present in healthy HCMV carriers. Therefore, multiepitope approaches to immunomonitoring and immunotherapy will make optimal use of this potentially important class of HCMV-specific effector cells. [ABSTRACT FROM AUTHOR]

Objectives Extensive polymorphism of HLA class II genes is not restricted to the coding region of the gene. It extends also to the linked promoter region, where it forms the basis for different levels of individual allele’s expression. Differential expression of HLA class II alleles can shape an immune response and influence the risk of developing autoimmune disease. In addition to genetic variability, variation in epigenetic modifications, including DNA methylation, can be another cause of the uneven expression of individual alleles. We aimed to analyze the DNA methylation of promoter sequences and the levels of expression of individual DQA1 gene alleles, interallelic variation of these two characteristics and the relationship between them. Methods The 60 healthy donors included into study were HLA-DRB1, HLA-DQB1 and HLA-DQA1 genotyped using PCR-SSP. Genomic DNA was treated by sodium bisulfite and the target segment in the HLA-DQA1 gene promoter was PCR amplified. PCR product was cloned into Escherichia coli and individual clones were sequenced. Transcripts of individual DQA1 alleles in peripheral blood leukocytes were quantified by Real-Time PCR. Results In this study, we have described detailed DNA methylation profile of promoter area of DQA1 gene alleles. The overall promoter methylation is increased for DQA1*02:01 and DQA1*04:01 alleles, on the other side, DQA1*05:01 allele shows decreased methylation level. Our results suggest that there are only minor interindividual differences in DRA-normalized expression level of specific allele. Furthermore, expression levels of individual alleles followed DQA1*03 > *01:03 (in DRB1*13-DQA1*01:03-DQB1*06:03 haplotype) > *01:01,*05:05, and DQA1*03 > *02:01 > *05:05 hierarchy. The statistically significantly most expressed allele, DQA1*03, comprises part of DQ8 molecule, which is commonly linked to autoimmune diseases. A clear relationship between promoter DNA methylation and mRNA expression level of the DQA1 gene could not be identified. [ABSTRACT FROM AUTHOR]

Background Immunocomplex capture fluorescence analysis (ICFA) detects donor-specific antihuman leukocyte antigen (HLA) antibodies (DSA), but the detection sensitivity of HLA class II antibodies using conventional ICFA is as low as 57%. The aim of the study was to improve the detection sensitivity of HLA class II antibodies by ICFA, and compare the ICFA results with the Luminex single-antigen bead test. Methods Six DSA-negative kidney transplant donors and recipient pairs and 10 HLA class II DSA-positive pairs were included in the study. The detection sensitivity of modified ICFA was compared with conventional ICFA, and the ICFA results were compared with the Luminex single-antigen bead test. Results The index value of modified ICFA was higher than that of conventional ICFA. The cutoff value of conventional ICFA was 30,686 (MFI), which was improved to 19,405 using modified ICFA. Regarding the HLA-DQ antibody, 5 samples found to be positive by Luminex single-antigen bead testing were all negative using modified ICFA. The reason for this discrepancy could be related to: (1) the difference in detection sensitivity; (2) the difference in HLA antigen surface expression between naive lymphocytes and synthetic beads; or (3) the structure of synthetic HLA DQ antigen on the Luminex single-antigen beads. Conclusion The index value of the modified ICFA was higher than that of conventional ICFA, and the detection sensitivity of HLA class II antibodies was improved by modified ICFA. Further assessment is necessary to clarify the reasons for divergence between ICFA and Luminex single-antigen bead test results. [ABSTRACT FROM AUTHOR]

Peptides bind MHC class II molecules through a thermodynamically nonadditive process consequent to the flexibility of the reactants. Currently, how the specific outcome of this binding process affects the ensuing epitope selection needs resolution. Calorimetric assessment of binding thermodynamics for hemagglutinin 306-319 peptide variants to the human MHC class II HLA-DR1 (DR1) and a mutant DR1 reveals that peptide/DR1 complexes can be formed with different enthalpic and entropic contributions. Complexes formed with a smaller entropic penalty feature circular dichroism spectra consistent with a non-compact form, and molecular dynamics simulation shows a more flexible structure. The opposite binding mode, compact and less flexible, is associated with greater entropic penalty. These structural variations are associated with rearrangements of residues known to be involved in HLA-DR (DM) binding, affinity of DM for the complex, and complex susceptibility to DM-mediated peptide exchange. Thus, the thermodynamic mechanism of peptide binding to DR1 correlates with the structural rigidity of the complex, and DM mediates peptide exchange by "sensing" flexible complexes in which the aforementioned residues are rearranged at a higher frequency than in more rigid ones. [ABSTRACT FROM AUTHOR]

Introduction The objective of the study was to determine the association of host human leukocyte antigen (HLA) class II genotype DRB1 alleles with the response to interferon therapy, viral loads and extent of liver fibrosis in a group of Romanian patients diagnosed with chronic hepatitis C, with different clinical outcomes. Class II HLA genes, particularly the HLA-DRB1 and DQB1 genes, have been shown to have an important role in self-limiting or persistent viral infection, in different genetic populations. In chronic hepatitis C both susceptible and protective alleles have been described, influencing the development of autoimmunity and progression to cirrhosis and hepatocellular carcinoma. Methods The study included 54 patients diagnosed with chronic hepatitis C, registered and monitored from January 2014 to January 2015 at the Clinical Hospital of Infectious Diseases, Constanţa, Romania. The selected patients were positive for anti-HCV antibodies and HCV-RNA, with screening laboratory results indicating HCV genotype 1b. The method used for the assignment of alleles at HLADRB1 and DQB1 loci was molecular genotyping, by the sequence specific oligonucleotide (SSO) hybridization method, and when required, by the sequence specific primers method (SSP). The presence of different alleles in patients has been analyzed for statistical significance. Results The presence of HLA-DRB1*0301 had a high frequency (14.8%) in null-responders (NR) while alleles DRB1*0701 (11.1%), DRB1*11# (22.2%) and DRB1*0101 (16.7%) were prevalent in sustained virologic responders (SVR). No significant correlation was found between the presence of HLA-DRB1* alleles and viral loads or liver fibrosis with p values not statistically significant after the Bonferroni correction. Conclusion The presented data suggest that in this group of Romanian patients, certain HLA alleles influence the therapeutic response in HCV infection and genetic predisposition may play a role in hepatitis C virus infection in those patients. [ABSTRACT FROM AUTHOR]

HLA class II antigens are central in initiating antigen-specific CD4+ T cell responses to HIV-1. Specific alleles have been associated with differential responses to HIV-1 infection and disease among adults. This study aims to determine the influence of HLA class II genes and their interactive effect on mother-child perinatal transmission in a drug naïve, Mother-Child HIV transmission cohort established in Kenya, Africa in 1986. Our study showed that DRB concordance between mother and child increased risk of perinatal HIV transmission by three fold (P = 0.00035/Pc = 0.0014, OR: 3.09, 95%CI, 1.64-5.83). Whereas, DPA1, DPB1 and DQB1 concordance between mother and child had no significant influence on perinatal HIV transmission. In addition, stratified analysis showed that DRB1*15:03+ phenotype (mother or child) significantly increases the risk of perinatal HIV-1 transmission. Without DRB1*15:03, DRB1 discordance between mother and child provided 5 fold protection (P = 0.00008, OR: 0.186, 95%CI: 0.081-0.427). However, the protective effect of DRB discordance was diminished if either the mother or the child was DRB1*15:03+ phenotype (P = 0.49-0.98, OR: 0.7-0.99, 95%CI: 0.246-2.956). DRB3+ children were less likely to be infected perinatally (P = 0.0006, Pc = 0.014; OR:0.343, 95%CI:0.183-0.642). However, there is a 4 fold increase in risk of being infected at birth if DRB3+ children were born to DRB1*15:03+ mother compared to those with DRB1*15:03- mother. Our study showed that DRB concordance/discordance, DRB1*15:03, children’s DRB3 phenotype and their interactions play an important role in perinatal HIV transmission. Identification of genetic factors associated with protection or increased risk in perinatal transmission will help develop alternative prevention and treatment methods in the event of increases in drug resistance of ARV. [ABSTRACT FROM AUTHOR]

Human leukocyte antigen (HLA) typing from next generation sequencing (NGS) data has the potential for widespread applications. Here we introduce a novel tool (HLAreporter) for HLA typing from NGS data based on read-mapping using a comprehensive reference panel containing all known HLA alleles, followed by de novo assembly of the gene-specific short reads. Accurate HLA typing at high-digit resolution was achieved when it was tested on publicly available NGS data, outperforming other newly developed tools such as HLAminer and PHLAT. HLAreporter can be downloaded from http://paed.hku.hk/genome/. [ABSTRACT FROM AUTHOR]