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1.  IFN-γ production in response to in vitro stimulation with collagen type II in rheumatoid arthritis is associated with HLA-DRB1*0401 and HLA-DQ8 
Arthritis Research  1999;2(1):75-84.
IFN-γ was measured in supernatants after in vitro stimulation of peripheral blood mononuclear cells with collagen type II (CII), purified protein derivative or influenza virus. IFN-γ production in response to CII was similar in rheumatoid arthritis (RA) patients and healthy control individuals. The IFN-γ response to purified protein derivative and influenza virus was lower in RA patients, reflecting a general T-cell hyporesponsiveness in RA. After recalculating the response to CII taking this hyporesponsiveness into account the CII response was higher in RA patients, and was associated with human leucocyte antigen (HLA)-DRB1*0401 and HLA-DQA1*0301-DQB1*0302 (HLA-DQ8). Rheumatoid arthritis patients with elevated serum levels of immunoglobulin (Ig)G anti-CII antibodies had lower CII-induced IFN-γ production than patients with low anti-CII levels. The relative increase in CII-reactivity in RA patients as compared with healthy control individuals, and the association of a higher response with RA-associated HLA haplotypes, suggest the existence of a potentially pathogenic cellular reactivity against CII in RA.
Despite much work over past decades, whether antigen-specific immune reactions occur in rheumatoid arthritis (RA) and to what extent such reactions are directed towards joint-specific autoantigens is still questionable. One strong indicator for antigenic involvement in RA is the fact that certain major histocompatibility complex (MHC) class II genotypes [human leucocyte antigen (HLA)-DR4 and HLA-DR1] predispose for the development of the disease [1]. In the present report, collagen type II (CII) was studied as a putative autoantigen on the basis of both clinical and experimental data that show an increased frequency of antibodies to CII in RA patients [2,3,4] and that show that CII can induce experimental arthritis [5].
It is evident from the literature that RA peripheral blood mononuclear cells (PBMCs) respond poorly to antigenic stimulation [6,7,8], and in particular evidence for a partial tolerization to CII has been presented [9]. The strategy of the present work has accordingly been to reinvestigate T-cell reactivity to CII in RA patients, to relate it to the response to commonly used recall antigens and to analyze IFN-γ responses as an alternative to proliferative responses.
To study cellular immune reactivity to CII in patients with RA and in healthy control individuals and to correlate this reactivity to HLA class II genotypes and to the presence of antibodies to CII in serum.
Forty-five patients who met the 1987 American College of Rheumatology classification criteria for RA [10] and 25 healthy control individuals of similar age and sex were included. Twenty-six of these patients who had low levels of anti-CII in serum were randomly chosen, whereas 19 patients with high anti-CII levels were identified by enzyme-linked immunosorbent assay (ELISA)-screening of 400 RA sera.
Heparinized blood was density gradient separated and PBMCs were cultured at 1 × 106/ml in RPMI-10% fetal calf serum with or without antigenic stimulation: native or denatured CII (100 μ g/ml), killed influenza virus (Vaxigrip, Pasteur Mérieux, Lyon, France; diluted 1 : 1000) or purified protein derivative (PPD; 10 μ g/ml). CII was heat-denatured in 56°C for 30 min.
Cell supernatants were collected after 7days and IFN-γ contents were analyzed using ELISA. HLA-DR and HLA-DQ genotyping was performed utilizing a polymerase chain reaction-based technique with sequence-specific oligonucleotide probe hybridization. Nonparametric statistical analyses were utilized throughout the study.
PBMCs from both RA patients and healthy control individuals responded with inteferon-γ production to the same degree to stimulation with native and denatured CII (Fig. 1a), giving median stimulation indexes with native CII of 4.6 for RA patients and 5.4 for healthy control individuals, and with denatured CII of 2.9 for RA patients and 2.6 for healthy control individuals. RA patients with elevated levels of anti-CII had a weaker IFN-γ response to both native and denatured CII than did healthy control individuals (P = 0.02 and 0.04, respectively).
Stimulation with the standard recall antigens PPD and killed influenza virus yielded a median stimulation index with PPD of 10.0 for RA patients and 51.3 for healthy control individuals and with influenza of 12.3 for RA patients and 25.7 for healthy, control individuals. The RA patients displayed markedly lower responsiveness to both PPD and killed influenza virus than did healthy control individuals (Fig. 1b). IFN-γ responses to all antigens were abrogated when coincubating with antibodies blocking MHC class II.
The low response to PPD and killed influenza virus in RA patients relative to that of healthy control individuals reflects a general downregulation of antigen-induced responsiveness of T cells from RA patients [6,7,8]. That no difference between the RA group and the control group was recorded in CII-induced IFN-γ production therefore indicates that there may be an underlying increased responsiveness to CII in RA patients, which is obscured by the general downregulation of T-cell responsiveness in these patients. In order to address this possibility, we calculated the fraction between individual values for the CII-induced IFN-γ production and the PPD-induced and killed influenza virus-induced IFN-γ production, and compared these fractions. A highly significant difference between the RA and healthy control groups was apparent after stimulation with both native CII and denatured CII when expressing the response as a fraction of that with PPD (Fig. 2a). Similar data were obtained using killed influenza virus-stimulated IFN-γ values as the denominator (Fig. 2b).
When comparing the compensated IFN-γ response to denatured CII stimulation between RA patients with different HLA genotypes, highly significant differences were evident, with HLA-DRB1*0401 patients having greater CII responsiveness than patients who lacked this genotype (Fig. 3a). HLA-DQ8 positive patients also displayed a high responsiveness to CII as compared with HLA-DQ8 negative RA patients (Fig. 3b). These associations between the relative T-cell reactivity to denatured CII and HLA class II genotypes were not seen in healthy control individuals. Similar results were achieved using influenza as denominator (P = 0.02 for HLA-DRB1*0401 and P = 0.01 for HLA-DQ8).
No reports have previously systematically taken the general T-cell hyporesponsiveness in RA into account when investigating specific T-cell responses in this disease. In order to address this issue we used the T-cell responses to PPD and killed influenza virus as reference antigens. This was made on the assumption that exposure to these antigens is similar in age-matched and sex-matched groups of RA patients and healthy control individuals. The concept of a general hyporesponsiveness in RA T cells has been documented in several previous reports, in which both nominal antigens [6,7,8] and mitogens [11,12,13] have been used. The fact that a similar functional downregulation in RA PBMCs was obtained with both PPD and killed influenza virus as reference antigens strengthens the validity of our approach.
We identified an association between the IFN-γ response to CII and HLA-DRB1*0401 and HLA-DQ8 in the RA patient group, which is of obvious interest because both these MHC class II alleles have been associated with high responsiveness to CII in transgenic mice that express these human MHC class II molecules [14,15]. There was no association between high anti-CII levels and shared epitope (HLA-DRB1*0401 or HLA-DRB1*0404).
CII, a major autoantigen candidate in RA, can elicit an IFN-γ response in vitro that is associated with HLA-DRB1*0401 and HLA-DQ8 in RA patients. This study, with a partly new methodological approach to a classical problem in RA, has provided some additional support to the notion that CII may be a target autoantigen of importance for a substantial group of RA patients. Continued efforts to identify mechanisms behind the general hyporesponsiveness to antigens in RA, as well as the mechanisms behind the potential partial anergy to CII, may provide us with better opportunities to study the specificity and pathophysiological relevance of anti-CII reactivity in RA.
PMCID: PMC17806  PMID: 11219392
collagen type II; human leucocyte antigen-DR; IFN-γ; rheumatoid arthritis; T cell
2.  Major histocompatibility complex (MHC) class II alleles, haplotypes and epitopes which confer susceptibility or protection in systemic sclerosis: analyses in 1300 Caucasian, African-American and Hispanic cases and 1000 controls 
Annals of the rheumatic diseases  2009;69(5):822-827.
To determine human leucocyte antigen-class II (HLA-class II) (DRB1, DQB1, DQA1 and DPB1) alleles, haplotypes and shared epitopes associated with scleroderma (systemic sclerosis (SSc)) and its subphenotypes in a large multi-ethnic US cohort by a case–control association study.
Patients and methods
1300 SSc cases (961 white, 178 black and 161 Hispanic subjects) characterised for clinical skin forms (limited vs diffuse), SSc-specific autoantibodies (anticentromere (ACA), anti-topoisomerase I (ATA), anti-RNA polymerase III (ARA), anti-U3 ribonucleoprotein (fibrillarin)) and others were studied using molecular genotyping. Statistical analyses in SSc itself by ethnicity, gender, skin type and autoantibodies were performed using exact logistic regression modelling for dominant, additive and recessive effects from HLA.
The strongest positive class II associations with SSc in white and Hispanic subjects were the DRB1*1104, DQA1*0501, DQB1*0301 haplotype and DQB1 alleles encoding a non-leucine residue at position 26 (DQB1 26 epi), while the DRB1*0701, DQA1*0201, DQB1*0202 haplotype and DRB1*1501 haplotype were negatively correlated and possibly protective in dominant and recessive models, respectively. These associations did not discriminate between limited and diffuse SSc. SSc in black subjects was associated with DRB1*0804, DQA1*0501, DQB1*0301 alleles. DPB1*1301 showed the highest odds ratio for ATA (OR = 14). Moreover, it showed no linkage disequilibrium or gene interaction with DR/DQ. ACA was best explained by DQB1*0501 and DQB1*26 epi alleles and ARA by DRB1*0404, DRB1*11 and DQB1*03 alleles in white and Hispanic subjects but DRB1*08 in black subjects.
These data indicate unique and multiple HLA-class II effects in SSc, especially on autoantibody markers of different subphenotypes.
PMCID: PMC2916702  PMID: 19596691
3.  Major histocompatibility complex (MHC) class II alleles, haplotypes and epitopes which confer susceptibility or protection in systemic sclerosis: analyses in 1300 Caucasian, African-American and Hispanic cases and 1000 controls 
Annals of the Rheumatic Diseases  2010;69(5):822-827.
To determine human leucocyte antigen-class II (HLA-class II) (DRB1, DQB1, DQA1 and DPB1) alleles, haplotypes and shared epitopes associated with scleroderma (systemic sclerosis (SSc)) and its subphenotypes in a large multi-ethnic US cohort by a case–control association study.
Patients and methods
1300 SSc cases (961 white, 178 black and 161 Hispanic subjects) characterised for clinical skin forms (limited vs diffuse), SSc-specific autoantibodies (anticentromere (ACA), anti-topoisomerase I (ATA), anti-RNA polymerase III (ARA), anti-U3 ribonucleoprotein (fibrillarin)) and others were studied using molecular genotyping. Statistical analyses in SSc itself by ethnicity, gender, skin type and autoantibodies were performed using exact logistic regression modelling for dominant, additive and recessive effects from HLA.
The strongest positive class II associations with SSc in white and Hispanic subjects were the DRB1*1104, DQA1*0501, DQB1*0301 haplotype and DQB1 alleles encoding a non-leucine residue at position 26 (DQB1 26 epi), while the DRB1*0701, DQA1*0201, DQB1*0202 haplotype and DRB1*1501 haplotype were negatively correlated and possibly protective in dominant and recessive models, respectively. These associations did not discriminate between limited and diffuse SSc. SSc in black subjects was associated with DRB1*0804, DQA1*0501, DQB1*0301 alleles. DPB1*1301 showed the highest odds ratio for ATA (OR = 14). Moreover, it showed no linkage disequilibrium or gene interaction with DR/DQ. ACA was best explained by DQB1*0501 and DQB1*26 epi alleles and ARA by DRB1*0404, DRB1*11 and DQB1*03 alleles in white and Hispanic subjects but DRB1*08 in black subjects.
These data indicate unique and multiple HLA-class II effects in SSc, especially on autoantibody markers of different subphenotypes.
PMCID: PMC2916702  PMID: 19596691
4.  Expression of the Multiple Sclerosis-Associated MHC Class II Allele HLA-DRB1*1501 Is Regulated by Vitamin D 
PLoS Genetics  2009;5(2):e1000369.
Multiple sclerosis (MS) is a complex trait in which allelic variation in the MHC class II region exerts the single strongest effect on genetic risk. Epidemiological data in MS provide strong evidence that environmental factors act at a population level to influence the unusual geographical distribution of this disease. Growing evidence implicates sunlight or vitamin D as a key environmental factor in aetiology. We hypothesised that this environmental candidate might interact with inherited factors and sought responsive regulatory elements in the MHC class II region. Sequence analysis localised a single MHC vitamin D response element (VDRE) to the promoter region of HLA-DRB1. Sequencing of this promoter in greater than 1,000 chromosomes from HLA-DRB1 homozygotes showed absolute conservation of this putative VDRE on HLA-DRB1*15 haplotypes. In contrast, there was striking variation among non–MS-associated haplotypes. Electrophoretic mobility shift assays showed specific recruitment of vitamin D receptor to the VDRE in the HLA-DRB1*15 promoter, confirmed by chromatin immunoprecipitation experiments using lymphoblastoid cells homozygous for HLA-DRB1*15. Transient transfection using a luciferase reporter assay showed a functional role for this VDRE. B cells transiently transfected with the HLA-DRB1*15 gene promoter showed increased expression on stimulation with 1,25-dihydroxyvitamin D3 (P = 0.002) that was lost both on deletion of the VDRE or with the homologous “VDRE” sequence found in non–MS-associated HLA-DRB1 haplotypes. Flow cytometric analysis showed a specific increase in the cell surface expression of HLA-DRB1 upon addition of vitamin D only in HLA-DRB1*15 bearing lymphoblastoid cells. This study further implicates vitamin D as a strong environmental candidate in MS by demonstrating direct functional interaction with the major locus determining genetic susceptibility. These findings support a connection between the main epidemiological and genetic features of this disease with major practical implications for studies of disease mechanism and prevention.
Author Summary
Multiple Sclerosis (MS) is a complex neurological disease with a strong genetic component. The Major Histocompatibility Complex (MHC) on chromosome 6 exerts the strongest genetic effect on disease risk. A region at or near the HLA-DRB1 locus in the MHC influences the risk of MS. HLA-DRB1 has over 400 different alleles. The dominant haplotype of Northern Europe, marked by the presence of DRB1*1501, increases risk of MS by 3-fold. The environment also plays a key role in MS. The most striking illustration of this is the geographical distribution of the disease in populations matched for ethnicity. This has led to the proposal that sunshine, and in particular, vitamin D, is an environmental factor influencing the risk of MS. Circumstantial evidence supporting this comes from studies showing the involvement of vitamin D in immune and nervous system function. The current investigation sought to uncover any relationship between vitamin D and HLA-DRB1. It was found that vitamin D specifically interacts with HLA-DRB1*1501 to influence its expression. This study therefore provides more direct support for the already strong epidemiological evidence implicating sunlight and vitamin D in the determination of MS risk, and implies that vitamin D supplementation at critical time periods may be key to disease prevention.
PMCID: PMC2627899  PMID: 19197344
5.  Influence of HLA-DRB1 and HLA-DQB1 Alleles on IgG Antibody Response to the P. vivax MSP-1, MSP-3α and MSP-9 in Individuals from Brazilian Endemic Area 
PLoS ONE  2012;7(5):e36419.
The antibody response generated during malaria infections is of particular interest, since the production of specific IgG antibodies is required for acquisition of clinical immunity. However, variations in antibody responses could result from genetic polymorphism of the HLA class II genes. Given the increasing focus on the development of subunit vaccines, studies of the influence of class II alleles on the immune response in ethnically diverse populations is important, prior to the implementation of vaccine trials.
Methods and Findings
In this study, we evaluated the influence of HLA-DRB1* and -DQB1* allelic groups on the naturally acquired humoral response from Brazilian Amazon individuals (n = 276) against P. vivax Merozoite Surface Protein-1 (MSP-1), MSP-3α and MSP-9 recombinant proteins. Our results provide information concerning these three P. vivax antigens, relevant for their role as immunogenic surface proteins and vaccine candidates. Firstly, the studied population was heterogeneous presenting 13 HLA-DRB1* and 5 DQB1* allelic groups with a higher frequency of HLA-DRB1*04 and HLA-DQB1*03. The proteins studied were broadly immunogenic in a naturally exposed population with high frequency of IgG antibodies against PvMSP1-19 (86.7%), PvMSP-3 (77%) and PvMSP-9 (76%). Moreover, HLA-DRB1*04 and HLA-DQB1*03 alleles were associated with a higher frequency of IgG immune responses against five out of nine antigens tested, while HLA-DRB1*01 was associated with a high frequency of non-responders to repetitive regions of PvMSP-9, and the DRB1*16 allelic group with the low frequency of responders to PvMSP3 full length recombinant protein.
HLA-DRB1*04 alleles were associated with high frequency of antibody responses to five out of nine recombinant proteins tested in Rondonia State, Brazil. These features could increase the success rate of future clinical trials based on these vaccine candidates.
PMCID: PMC3359319  PMID: 22649493
6.  HLA-DRB1 as a risk factor in children with autoimmune hepatitis and its relation to hepatitis A infection 
The human leukocyte antigens (HLAs) are proteins found in the membranes of nearly all nucleated cells. People with certain HLA antigens are more likely to develop certain autoimmune diseases. The aim of this study was to determine the frequency of HLA-DRB1 in children with autoimmune hepatitis (AIH) as a risk factor for occurrence, its relation to preceding hepatitis A infection and treatment outcome.
Subjects and methods
25 children with AIH were subjected to HLA-DRB 1 typing performed by sequence specific oligonucleotide probe technique and compared to HLA-DRB1 found in 548 normal populations.
The most frequent alleles found in our children with AIH were HLA-DRB1*13 (36%), HLA-DRB1*04 (18%) and HLA-DRB1*03 (14%). HLA-DRB1*13 was significantly more frequent in AIH patients compared to controls. In type I AIH patients HLA-DRB1*13 was the most frequent allele (32.4%), followed by HLA-DRB1*04 in (20.6%) and HLA-DRB1*03 in (14.7%), While in type II, the most frequent alleles were HLA-DRB1*13 in (40%), HLA-DRB1*07 (20%) and HLA-DRB1*15 in (20%). HLA-DRB1*12 was significantly more frequent in AIH patients with positive Hepatitis A IgM than in patients with negative hepatitis A IgM. No statistically significant difference between partial responders and complete responders to treatment as regards HLA-DRB1 subtypes.
It is concluded from the previous study that HLA-DRB1*13 may be a susceptibility allele for the occurrence of autoimmune hepatitis in our population. HLA-DRB1*07 and HLA-DRB1*15 may be susceptibility alleles for occurrence of autoimmune hepatitis type 2. HLA-DRB1*12 association with AIH in patients triggered by hepatitis A needs further studies.
PMCID: PMC2992538  PMID: 21067577
7.  Next Generation Sequencing Reveals the Association of DRB3*02:02 With Type 1 Diabetes 
Diabetes  2013;62(7):2618-2622.
The primary associations of the HLA class II genes, HLA-DRB1 and HLA-DQB1, and the class I genes, HLA-A and HLA-B, with type 1 diabetes (T1D) are well established. However, the role of polymorphism at the HLA-DRB3, HLA-DRB4, and HLA-DRB5 loci remains unclear. In two separate studies, one of 500 subjects and 500 control subjects and one of 366 DRB1*03:01–positive samples from selected multiplex T1D families, we used Roche 454 sequencing with Conexio Genomics ASSIGN ATF 454 HLA genotyping software analysis to analyze sequence variation at these three HLA-DRB loci. Association analyses were performed on the two HLA-DRB loci haplotypes (DRB1-DRB3, -DRB4, or -DRB5). Three common HLA-DRB3 alleles (*01:01, *02:02, *03:01) were observed. DRB1*03:01 haplotypes carrying DRB3*02:02 conferred a higher T1D risk than did DRB1*03:01 haplotypes carrying DRB3*01:01 in DRB1*03:01/*03:01 homozygotes with two DRB3*01:01 alleles (odds ratio [OR] 3.4 [95% CI 1.46–8.09]), compared with those carrying one or two DRB3*02:02 alleles (OR 25.5 [3.43–189.2]) (P = 0.033). For DRB1*03:01/*04:01 heterozygotes, however, the HLA-DRB3 allele did not significantly modify the T1D risk of the DRB1*03:01 haplotype (OR 7.7 for *02:02; 6.8 for *01:01). These observations were confirmed by sequence analysis of HLA-DRB3 exon 2 in a targeted replication study of 281 informative T1D family members and 86 affected family-based association control (AFBAC) haplotypes. The frequency of DRB3*02:02 was 42.9% in the DRB1*03:01/*03:01 patients and 27.6% in the DRB1*03:01/*04 (P = 0.005) compared with 22.6% in AFBAC DRB1*03:01 chromosomes (P = 0.001). Analysis of T1D-associated alleles at other HLA loci (HLA-A, HLA-B, and HLA-DPB1) on DRB1*03:01 haplotypes suggests that DRB3*02:02 on the DRB1*03:01 haplotype can contribute to T1D risk.
PMCID: PMC3712046  PMID: 23462545
8.  DQB1*0602 rather than DRB1*1501 confers susceptibility to multiple sclerosis-like disease induced by proteolipid protein (PLP) 
Multiple sclerosis (MS) is associated with pathogenic autoimmunity primarily focused on major CNS-myelin target antigens including myelin basic protein (MBP), proteolipidprotein (PLP), myelin oligodendrocyte protein (MOG). MS is a complex trait whereby the HLA genes, particularly class-II genes of HLA-DR15 haplotype, dominate the genetic contribution to disease-risk. Due to strong linkage disequilibrium in HLA-II region, it has been hard to establish precisely whether the functionally relevant effect derives from the DRB1*1501, DQA1*0102-DQB1*0602, or DRB5*0101 loci of HLA-DR15 haplotype, their combinations, or their epistatic interactions. Nevertheless, most genetic studies have indicated DRB1*1501 as a primary risk factor in MS. Here, we used 'HLA-humanized' mice to discern the potential relative contribution of DRB1*1501 and DQB1*0602 alleles to susceptibility to "humanized" MS-like disease induced by PLP, one of the most prominent and encephalitogenic target-antigens implicated in human MS.
The HLA-DRB1*1501- and HLA-DQB1*0602-Tg mice (MHC-II-/-), and control non-HLA-DR15-relevant-Tg mice were immunized with a set of overlapping PLP peptides or with recombinant soluble PLP for induction of "humanized" MS-like disease, as well as for ex-vivo analysis of immunogenic/immunodominant HLA-restricted T-cell epitopes and associated cytokine secretion profile.
PLP autoimmunity in both HLA-DR15-Tg mice was focused on 139-151 and 175-194 epitopes. Strikingly, however, the HLA-DRB1*1501-transgenics were refractory to disease induction by any of the overlapping PLP peptides, while HLA-DQB1*0602 transgenics were susceptible to disease induction by PLP139-151 and PLP175-194 peptides. Although both transgenics responded to both peptides, the PLP139-151- and PLP175-194-reactive T-cells were directed to Th1/Th17 phenotype in DQB1*0602-Tg mice and towards Th2 in DRB1*1501-Tg mice.
While genome studies map a strong MS susceptibility effect to the region of DRB1*1501, our findings offer a rationale for potential involvement of pathogenic DQ6-associated autoimmunity in MS. Moreover, that DQB1*0602, but not DRB1*1501, determines disease-susceptibility to PLP in HLA-transgenics, suggests a potential differential, functional role for DQB1*0602 as a predisposing allele in MS. This, together with previously demonstrated disease-susceptibility to MBP and MOG in DRB1*1501-transgenics, also suggests a differential role for DRB1*1501 and DQB1*0602 depending on target antigen and imply a potential complex 'genotype/target antigen/phenotype' relationship in MS heterogeneity.
PMCID: PMC3344688  PMID: 22316121
EAE/MS; Antigens/Peptides/Epitopes; Neuroimmunology; T Cells; MHC; HLA-Tg mice
9.  Consistency of HLA Associations between Two Independent Measles Vaccine Cohorts: A Replication Study 
Vaccine  2012;30(12):2146-2152.
Associations between HLA genotypes and measles vaccine humoral and cellular immune responses were examined to better understand immunogenetic drivers of vaccine response. Two independent study cohorts of healthy schoolchildren were examined: cohort one, 346 children between 12–18 years of age; and cohort two, 388 children between 11–19 years of age. All received two age-appropriate doses of measles-containing vaccine. The purpose of this study was to identify and replicate associations between HLA genes and immune responses following measles vaccination found in our first cohort. Associations of comparable magnitudes and with similar p-values were observed between B*3503 (1st cohort p=0.01; 2nd cohort p=0.07), DQA1*0201 (1st cohort p=0.03; 2nd cohort p=0.03), DQB1*0303 (1st cohort p=0.10; 2nd cohort p=0.02), DQB1*0602 (1st cohort p=0.07; 2nd cohort p=0.10), and DRB1*0701 (1st cohort p=0.03; 2nd cohort p=0.07) alleles and measles-specific antibody levels. Suggestive, yet consistent, associations were observed between the B7(1 st cohort p=0.01; 2nd cohort p=0.08) supertype and higher measles antibody levels in both cohorts. Also, in both cohorts, the B*0801 and DRB1*0301 alleles, C*0802 and DPA1*0202 alleles, and DRB1*1303 alleles displayed consistent associations with variations in IFN-γ, IL-2 and IL-10 secretion, respectively. This study emphasizes the importance of replicating HLA associations with measles vaccine-induced humoral and cellular immune responses and increases confidence in the results. These data will inform strategies for functional studies and novel vaccine development, including epitope-based measles vaccines. This is the first HLA association replication study with measles vaccine-specific immune responses to date.
PMCID: PMC3288791  PMID: 22285888
Measles vaccine; HLA genotypes; Haplotypes; Antibodies; Cytokines; Replication study
10.  The Inheritance of Resistance Alleles in Multiple Sclerosis 
PLoS Genetics  2007;3(9):e150.
Multiple sclerosis (MS) is a complex trait in which alleles at or near the class II loci HLA-DRB1 and HLA-DQB1 contribute significantly to genetic risk. HLA-DRB1*15 and HLA-DRB1*17-bearing haplotypes and interactions at the HLA-DRB1 locus increase risk of MS but it has taken large samples to identify resistance HLA-DRB1 alleles. In this investigation of 7,093 individuals from 1,432 MS families, we have assessed the validity, mode of inheritance, associated genotypes, and the interactions of HLA-DRB1 resistance alleles. HLA-DRB1*14-, HLA-DRB1*11-, HLA-DRB1*01-, and HLA-DRB1*10-bearing haplotypes are protective overall but they appear to operate by different mechanisms. The first type of resistance allele is characterised by HLA-DRB1*14 and HLA-DRB1*11. Each shows a multiplicative mode of inheritance indicating a broadly acting suppression of risk, but a different degree of protection. In contrast, a second type is exemplified by HLA-DRB1*10 and HLA-DRB1*01. These alleles are significantly protective when they interact specifically in trans with HLA-DRB1*15-bearing haplotypes. HLA-DRB1*01 and HLA-DRB1*10 do not interact with HLA-DRB1*17, implying that several mechanisms may be operative in major histocompatibility complex–associated MS susceptibility, perhaps analogous to the resistance alleles. There are major practical implications for risk and for the exploration of mechanisms in animal models. Restriction of antigen presentation by HLA-DRB1*15 seems an improbably simple mechanism of major histocompatibility complex–associated susceptibility.
Author Summary
Multiple sclerosis (MS) is a complex neurological disease with a strong genetic component. With the possible exception of a weak association at Chromosome 5p, the major histocompatibility complex is the only locus consistently linked to MS. Because of this the major histocompatibility complex has recently undergone renewed attention. A region at or near the gene HLA-DRB1 influences the risk of MS. HLA-DRB1 comes in over 400 different forms (or alleles). A common form in Europe, named 1501, increases risk of MS by 3-fold. In this paper, to our knowledge the largest-ever analysis of this region in MS, we examine the inheritance of newly discovered HLA-DRB1 MS resistance alleles, namely HLA-DRB1*14, HLA-DRB1*11, *10, and HLA-DRB1*01. We show that HLA-DRB1*14 and HLA-DRB1*11 are dominantly protective; e.g., HLA-DRB1*14 significantly reduces the risk associated with HLA-DRB1*15 when they are inherited together. This may explain, in part, why MS is rare in Asia; there, the HLA-DRB1*14 allele is frequent. HLA-DRB1*01 and HLA-DRB1*10 are protective only in the presence of HLA-DRB1*15. HLA-DRB1*14 and HLA-DRB1*11 haplotypes and HLA-DRB1*01 and HLA-DRB1*10 haplotypes share common ancestral origins and this may be why the alleles can be grouped in terms of their protective nature. Discovery of the mechanism of protection against MS may lead to the discovery of new treatments to make a palpable difference in the lives of those who have been affected by this devastating disease.
PMCID: PMC1971120  PMID: 17845076
11.  A cis-eQTL of HLA-DRB1 and a frameshift mutation of MICA contribute to the pattern of association of HLA alleles with cervical cancer 
Cancer Medicine  2014;3(2):445-452.
The association of classic human leukocyte antigen (HLA) alleles with risk of cervical cancer has been extensively studied, and a protective effect has consistently been found for DRB1*1301, DQA1*0103, and/or DQB1*0603 (these three alleles are in perfect linkage disequilibrium [LD] and often occur on the same haplotype in Europeans), while reports have differed widely with respect to the effect of HLA-B*07, DRB1*1501, and/or DQB1*0602 (the last two alleles are also in perfect LD in Europeans). It is not clear whether the reported HLA alleles are responsible for the differences in cervical cancer susceptibility, or if functional variants at other locations within the major histocompatibility complex (MHC) region may explain the effect. In order to assess the relative contribution of both classic HLA alleles and single-nucleotide polymorphisms (SNPs) within the MHC region to cervical cancer susceptibility, we have imputed classic HLA alleles in 1034 cervical cancer patients and 3948 controls in a Swedish population for an integrated analysis. We found that the protective haplotype DRB1*1301-DQA1*0103-DQB1*0603 has a direct effect on cervical cancer and always occurs together with the C allele of a HLA-DRB1 cis-eQTL (rs9272143), which increases the expression of HLA-DRB1. The haplotype rs9272143C-DRB1*1301-DQA1*0103-DQB1*0603 conferred the strongest protection against cervical cancer (odds ratio [OR] = 0.41, 95% confidence interval [CI] = 0.32–0.52, P = 6.2 × 10−13). On the other hand, the associations with HLA-B*0702 and DRB1*1501-DQB1*0602 are attributable to the joint effects of both the HLA-DRB1 cis-eQTL (rs9272143) and a frameshift mutation (G inserion of rs67841474, also known as A5.1) of the MHC class I polypeptide-related sequence A gene (MICA). Variation in LD between the classic HLA loci, rs9272143 and rs67841474 between populations may explain the different associations of HLA-B*07 and DRB1*1501-DQB1*0602 with cervical cancer between studies. The mechanism suggested may also explain similar inconsistent results for other HLA-associated diseases.
PMCID: PMC3987094  PMID: 24520070
Cervical cancer; cis-eQTL; frameshift mutation; HLA; MICA
12.  Human Leukocyte Antigen and Interleukin 2, 10 and 12p40 Cytokine Responses to Measles: Is There Evidence of the HLA Effect? 
Cytokine  2007;36(3-4):173-179.
HLA class I and class II associations were examined in relation to measles virus-specific cytokine responses in 339 healthy children who had received two doses of live attenuated measles vaccine. Multivariate linear regression modeling analysis revealed suggestions of associations between the expression of DPA1*0201 (p=0.03) and DPA1*0202 (p=0.09) alleles and interleukin-2 (IL-2) cytokine production (global p-value 0.06). Importantly, cytokine production and DQB1 allele associations (global p-value 0.04) revealed that the alleles with the strongest association with IL-10 secretion were DQB1*0302 (p=0.02), DQB1*0303 (p=0.07) and DQB1*0502 (p=0.06). Measles-specific IL-10 secretion associations approached significance with DRB1 and DQA1 loci (both global p-values 0.08). Specifically, suggestive associations were found between DRB1*0701 (p=0.07), DRB1*1103 (p=0.06), DRB1*1302 (p=0.08), DRB1*1303 (p=0.06), DQA1*0101 (p=0.08), and DQA1*0201 (p=0.04) alleles and measles-induced IL-10 secretion. Further, suggestive association was observed between specific DQA1*0505 (p=0.002) alleles and measles-specific IL-12p40 secretion (global p-value 0.09) indicating that cytokine responses to measles antigens are predominantly influenced by HLA class II genes. We found no associations between any of the alleles of HLA A, B, and Cw loci and cytokine secretion. These novel findings suggest that HLA class II genes may influence the level of cytokine production in the adaptive immune responses to measles vaccine.
PMCID: PMC1948883  PMID: 17234427
Measles Vaccine; HLA; Interleukin-2; Interleukin-10; Interleukin-12p40; ELISA
13.  Allele Polymorphism and Haplotype Diversity of HLA-A, -B and -DRB1 Loci in Sequence-Based Typing for Chinese Uyghur Ethnic Group 
PLoS ONE  2010;5(11):e13458.
Previous studies indicate that the frequency distributions of HLA alleles and haplotypes vary from one ethnic group to another or between the members of the same ethnic group living in different geographic areas. It is necessary and meaningful to study the high-resolution allelic and haplotypic distributions of HLA loci in different groups.
Methodology/Principal Findings
High-resolution HLA typing for the Uyghur ethnic minority group using polymerase chain reaction-sequence-based-typing method was first reported. HLA-A, -B and -DRB1 allelic distributions were determined in 104 unrelated healthy Uyghur individuals and haplotypic frequencies and linkage disequilibrium parameters for HLA loci were estimated using the maximum-likelihood method. A total of 35 HLA-A, 51 HLA-B and 33 HLA-DRB1 alleles were identified at the four-digit level in the population. High frequency alleles were HLA-A*1101 (13.46%), A*0201 (12.50%), A*0301 (10.10%); HLA-B*5101(8.17%), B*3501(6.73%), B*5001 (6.25%); HLA-DRB1*0701 (16.35%), DRB1*1501 (8.65%) and DRB1*0301 (7.69%). The two-locus haplotypes at the highest frequency were HLA-A*3001-B*1302 (2.88%), A*2402-B*5101 (2.86%); HLA-B*5001-DRB1*0701 (4.14%) and B*0702-DRB1*1501 (3.37%). The three-locus haplotype at the highest frequency was HLA-A*3001-B*1302-DRB1*0701(2.40%). Significantly high linkage disequilibrium was observed in six two-locus haplotypes, with their corresponding relative linkage disequilibrium parameters equal to 1. Neighbor-joining phylogenetic tree between the Uyghur group and other previously reported populations was constructed on the basis of standard genetic distances among the populations calculated using the four-digit sequence-level allelic frequencies at HLA-A, HLA-B and HLA-DRB1 loci. The phylogenetic analyses reveal that the Uyghur group belongs to the northwestern Chinese populations and is most closely related to the Xibe group, and then to Kirgiz, Hui, Mongolian and Northern Han.
The present findings could be useful to elucidate the genetic background of the population and to provide valuable data for HLA matching in clinical bone marrow transplantation, HLA-linked disease-association studies, population genetics, human identification and paternity tests in forensic sciences.
PMCID: PMC2973946  PMID: 21079793
14.  A shared HLA-DRB1 epitope in the DR beta first domain is associated with Vogt-Koyanagi-Harada syndrome in Indian patients 
Molecular Vision  2010;16:353-358.
Vogt-Koyanagi-Harada (VKH) disease and sympathetic ophthalmia (SO) are two distinct entities that share common clinical and histopathological features; however, it remains unknown whether they have a common genetic susceptibility. Several studies have shown an association of human leukocyte antigen (HLA)-DR4 with VKH disease in patients of different ethnic backgrounds. We present in this paper the HLA-DRB1 genotyping analysis of a large cohort of VKH patients from southern India and compare these patients to patients with SO and to healthy individuals from the same geographic area.
VKH patients were diagnosed according to the revised criteria of the International Committee on VKH disease. Patients with granulomatous uveitis after ocular trauma or multiple eye surgeries were diagnosed as having SO. Genomic DNA was extracted from all patients and controls. Samples were analyzed for HLA-DRB1 alleles by reverse polymerase chain reaction (PCR) sequence-specific oligonucleotide (SSO) hybridization on microbeads, using the Luminex technology, and by PCR sequence-specific primers (SSP) typing for DRB1*04 allele determination. Strength of associations was estimated by odds ratios (OR) and 95% confidence intervals (CI) and frequencies were compared using the Fisher’s exact test.
HLA-DRB1 alleles were determined in 94 VKH patients, 39 SO patients, and 112 healthy controls. HLA-DRB1*04 frequency was higher in VKH patients (20.2% versus 10.3% in controls; OR=2.2, p=0.005, pc=0.067). This association was lower than the association of HLA-DRB1*04 frequency in cohorts of patients from different origins. No significant DR4 association with SO was detected. HLA-DRB1*0405 and HLA-DRB1*0410 alleles were significantly increased in VKH patients (8.5% versus 0.9% in controls; OR=10.3, 95% CI=2.34–45.5, p<0.001). These two alleles share the epitope S57-LLEQRRAA (67–74) in the third hypervariable region of the HLA-DR molecule. None of the DRB1 alleles was significantly associated with SO.
Based on the association of HLA-DRB1*0405 and HLA-DRB1*0410 alleles with VKH disease, we propose that the epitope S57-LLEQRRAA (67–74) in the third hypervariable region of the HLA-DRβ1 molecule is the relevant susceptibility epitope. This genetic component seems specific to VKH disease since no correlation could be identified in SO patients. The weaker association with HLA-DR4 in this VKH patient cohort compared to VKH patients from northern India is probably related to the lower frequency of HLA-DRB1*0405 in our study group. The HLA-DRB1 association with susceptibility to VKH syndrome seems weaker in Indian patients compared to Japanese or Hispanic patients, suggesting a different non-HLA immunogenetic background in Indian VKH patients.
PMCID: PMC2834567  PMID: 20216938
15.  Immunogenetic Risk and Protective Factors for Development of L-tryptophan-associated Eosinophilia-Myalgia Syndrome and Associated Symptoms 
Arthritis and rheumatism  2009;61(10):1305-1311.
To assess L-tryptophan (LT) dose, age, gender and immunogenetic markers as possible risk or protective factors for development of LT-associated eosinophilia myalgia syndrome (EMS) and related clinical findings.
HLA DRB1 and DQA1 allele typing and GM/KM phenotyping were performed on a cohort of 94 Caucasian subjects with documented LT ingestion and standardized evaluations. Multivariate analyses compared LT dose, age, gender and alleles among groups of subjects who ingested LT and subsequently developed surveillance criteria for EMS (EMS), or developed EMS or characteristic features of EMS (EMS spectrum disorder), or developed no features of EMS (unaffected).
Considering all sources of LT, higher LT dose (odds ratio (OR) 1.4, 95% confidence interval (CI) 1.1-1.8), age >45 years (OR 3.0, CI 1.03-8.8) and HLA DRB1*03 (OR 3.9, CI 1.2-15.2), DRB1*04 (OR 3.9, CI 1.1-16.4) and DQA1*0601 (OR 13.7, CI 1.3-1874) were risk factors for the development of EMS, while DRB1*07 (OR 0.12, CI 0.02-0.48) and DQA1*0501 (OR 0.23, CI 0.05-0.85) were protective. Similar risk and protective factors were seen for developing EMS following ingestion of implicated LT, except DRB1*03 was not a risk factor and DQA1*0201 was an additional protective factor. EMS spectrum disorder also showed similar findings, but with DRB1*04 being a risk factor and DRB1*07 and DQA1*0201 being protective. There were no differences in gender distribution, GM/KM allotypes or GM/KM phenotypes among any groups.
In addition to the xenobiotic dose and subject age, polymorphisms in immune response genes may underlie the development of certain xenobiotic-induced immune-mediated disorders and these findings may have implications for future related epidemics.
PMCID: PMC2761987  PMID: 19790128
16.  Selection of epitope-based vaccine targets of HCV genotype 1 of Asian origin: a systematic in silico approach 
Bioinformation  2012;8(20):957-962.
Hepatitis C is the major health problem over the globe affecting approximately 200 million people worldwide and about 10 million Pakistani populations. Developing countries are especially facing the problems of HCV infection. Hence the goal of the study was to find out the antigenic epitopes that could be effective vaccine targets of HCV genotype 1 of Asian origin against HLA alleles frequently distributed in Asian countries. A total of 85 complete genome sequences of HCV 1 of Asian origin were retrieved from the HCV sequence database. Using in silico tools, T cell epitopes were predicted from conserved regions of all the available HCV 1 subtypes against Asian HLA alleles. Using 10 MHC I supertypes 51 epitopes was predicted as promiscuous binders. MHC class I supertypes A2 and B7 were found to be good promiscuous binders for a large number of predicted epitopes. Other alleles of MHC I supertypes (B57, B27, BX, B44) either were not respondent as promiscuous binders or responded only to a limited number of epitopes. Against 8 predominantly found Asian alleles of DRB1 supertype, 42 epitopes was predicted as promiscuous binders. MHC class II alleles DRB1-0101, DRB1-0701 and DRB1-1501 were the highest binders to promiscuous predicted epitopes while DRB1-0301 was the least binder for the predicted promiscuous epitopes of HCV 1 genotype of Asian origin. Literature review survey of predicted epitopes via IEDB also confirmed that great numbers of predicted epitopes are true positive. Hence, sophisticated selection of viral proteins and MHCs provided conserved promiscuous epitopes that can be used as effective vaccine candidates for all Asian counties.
HCV - hepatitis C virus, MHC - major histocompatability complex, HLA - human leukocyte antigen, CTL - cytotoxic T lymphocytes.
PMCID: PMC3524940  PMID: 23275687
Hepatitus C Virus; Immunoinformatics; MHC; Epitope; Conservancy; Asia
17.  Association of HLA-A, B, DRB1 alleles and haplotypes with HIV-1 infection in Chongqing, China 
The human immunodeficiency virus type 1(HIV-1) epidemic in Chongqing, China, is increasing rapidly with the dominant subtype of CRF07_BC over the past 3 years. Since human leukocyte antigen (HLA) polymorphisms have shown strong association with susceptibility/resistance to HIV-1 infection from individuals with different ethnic backgrounds, a recent investigation on frequencies of HLA class I and class II alleles in a Chinese cohort also indicated that similar correlation existed in HIV infected individuals from several provinces in China, however, such information is unavailable in Chongqing, southwest China.
In this population-based study, we performed polymerase chain reaction analysis with sequence-specific oligonucleotide probes (PCR-SSOP) for intermediate-low-resolution HLA typing in a cohort of 549 HIV-1 infected individuals, another 2475 healthy subjects from the Han nationality in Chongqing, China, were selected as population control. We compared frequencies of HLA-A, B, DRB1 alleles, haplotypes and genotypes between the two groups, and analyzed their association with HIV-1 susceptibility or resistance.
The genetic profile of HLA (A, B, DRB1) alleles of HIV-1 infected individuals from Chongqing Han of China was obtained. Several alleles of HLA-B such as B*46 (P = 0.001, OR = 1.38, 95%CI = 1.13-1.68), B*1501G(B62) (P = 0.013, OR = 1.42, 95%CI = 1.08-1.88), B*67 (P = 0.022, OR = 2.76, 95%CI = 1.16-6.57), B*37 (P = 0.014, OR = 1.93, 95%CI = 1.14-3.28) and B*52 (P = 0.038, OR = 1.64, 95%CI = 1.03-2.61) were observed to have association with susceptibility to HIV-1 infection in this population. In addition, the haplotype analysis revealed that A*11-B*46, A*24-B*54 and A*01-B*37 for 2-locus, and A*11-B*46-DRB1*09, A*02-B*46-DRB1*08, A*11-B*4001G-DRB1*15, A*02-B*4001G-DRB1*04, A*11-B*46-DRB1*08 and A*02-B*4001G-DRB1*12 for 3-locus had significantly overrepresented in HIV-1 infected individuals, whereas A*11-B*1502G, A*11-B*1502G-DRB1*12 and A*33-B*58-DRB1*13 were underrepresented. However, the low-resolution homozygosity of HLA-A, B, DRB1 loci and HLA-Bw4/Bw6 genotypes did not differ significantly between the two groups.
These results may contribute to the database of HLA profiles in HIV-1 infected Chinese population, consequently, the association of certain HLA alleles with susceptibility or resistance to HIV-1 infection would provide with clues in choosing proper preventive strategies against HIV-1 infection and developing effective HIV-1 vaccines in Chinese population, especially for those in southwest China.
PMCID: PMC2797796  PMID: 20003377
18.  HLA DR-DQ Haplotypes and Genotypes and Type 1 Diabetes Risk 
Diabetes  2008;57(4):1084-1092.
The Type 1 Diabetes Genetics Consortium has collected type 1 diabetic families worldwide for genetic analysis. The major genetic determinants of type 1 diabetes are alleles at the HLA-DRB1 and DQB1 loci, with both susceptible and protective DR-DQ haplotypes present in all human populations. The aim of this study is to estimate the risk conferred by specific DR-DQ haplotypes and genotypes.
Six hundred and seven Caucasian families and 38 Asian families were typed at high resolution for the DRB1, DQA1, and DQB1 loci. The association analysis was performed by comparing the frequency of DR-DQ haplotypes among the chromosomes transmitted to an affected child with the frequency of chromosomes not transmitted to any affected child.
A number of susceptible, neutral, and protective DR-DQ haplotypes have been identified, and a statistically significant hierarchy of type 1 diabetes risk has been established. The most susceptible haplotypes are the DRB1*0301-DQA1*0501-DQB1*0201 (odds ratio [OR] 3.64) and the DRB1*0405-DQA1*0301-DQB1*0302, DRB1*0401-DQA1*0301-DQB*0302, and DRB1*0402-DQA1*0301-DQB1*0302 haplotypes (ORs 11.37, 8.39, and 3.63), followed by the DRB1*0404-DQA1*0301-DQB1*0302 (OR 1.59) and the DRB1*0801-DQB1*0401-DQB1*0402 (OR 1.25) haplotypes. The most protective haplotypes are DRB1*1501-DQA1*0102-DQB1*0602 (OR 0.03), DRB1*1401-DQA1*0101-DQB1*0503 (OR 0.02), and DRB1*0701-DQA1*0201-DQB1*0303 (OR 0.02).
Specific combinations of alleles at the DRB1, DQA1, and DQB1 loci determine the extent of haplotypic risk. The comparison of closely related DR-DQ haplotype pairs with different type 1 diabetes risks allowed identification of specific amino acid positions critical in determining disease susceptibility. These data also indicate that the risk associated with specific HLA haplotypes can be influenced by the genotype context and that the trans-complementing heterodimer encoded by DQA1*0501 and DQB1*0302 confers very high risk.
PMCID: PMC4103420  PMID: 18252895
19.  Relation between HLA typing and clinical presentations in Systemic Lupus Erythematosus patients in Al-Qassim region, Saudi Arabia 
Systemic lupus erythematosus (SLE) is a disease with diverse clinical presentations due to interaction between genetic and environmental factors. SLE is associated worldwide with polymorphisms at various loci, including the major histocompatibility complex (MHC), although inconsistencies exist among these studies.
This study was carried out to investigate, the association of HLA-DRB1, DRB3, DRB4, DRB5, and DQB1 alleles in SLE patients and clinical presentations at Qassim, Saudi Arabia.
Fifty one patients with SLE—84.3% of whom had kidney involvement were studied in a case control study for HLA-DRB1, DRB3, DRB4, DRB5, and DQB1.
It was found that DRB3 is a protective gene among Saudi’s against SLE, HLA DRB3, HLA DRB1*11 frequency was increased in patients with serositis with a p value of (0.004), (0.047) respectively, increased frequency of HLA DQB1*3 among SLE patients with skin manifestations with a p value of (0.041), the frequency of HLA DRB1*15 alleles was increased among SLE patients with nephritis with a p value of (0.029), the frequency of HLA DRB1*11 among those with hematological manifestations with a p value of (0.03) and the frequency DRB1*10 was found to be increased among SLE patients with neurological manifestations with a p value of (0.002)
In contradistinction to what have been found among other populations DRB3 is a protective gene among Saudi’s against SLE. No evidence for a role of the HLA-DRB1, DRB4, DRB5, DQB1 alleles. There was an increased HLA DRB3 frequency with serositis, DQB1*3 skin manifestations, HLA DRB1*15 with nephritis, DRB1*10 with hematological manifestations and DRB1*11 with neurological manifestations.
PMCID: PMC4166988  PMID: 25246883
SLE; HLA; Saudi; disease clinical expression; lupus
20.  Diversity of Extended HLA-DRB1 Haplotypes in the Finnish Population 
PLoS ONE  2013;8(11):e79690.
The Major Histocompatibility Complex (MHC, 6p21) codes for traditional HLA and other host response related genes. The polymorphic HLA-DRB1 gene in MHC Class II has been associated with several complex diseases. In this study we focus on MHC haplotype structures in the Finnish population. We explore the variability of extended HLA-DRB1 haplotypes in relation to the other traditional HLA genes and a selected group of MHC class III genes. A total of 150 healthy Finnish individuals were included in the study. Subjects were genotyped for HLA alleles (HLA-A, -B, -DRB1, -DQB1, and -DPB1). The polymorphism of TNF, LTA, C4, BTNL2 and HLA-DRA genes was studied with 74 SNPs (single nucleotide polymorphism). The C4A and C4B gene copy numbers and a 2-bp silencing insertion at exon 29 in C4A gene were analysed with quantitative genomic realtime-PCR. The allele frequencies for each locus were calculated and haplotypes were constructed using both the traditional HLA alleles and SNP blocks. The most frequent Finnish A∼B∼DR -haplotype, uncommon in elsewhere in Europe, was A*03∼B*35∼DRB1*01∶01. The second most common haplotype was a common European ancestral haplotype AH 8.1 (A*01∼B*08∼DRB1*03∶01). Extended haplotypes containing HLA-B, TNF block, C4 and HLA-DPB1 strongly increased the number of HLA-DRB1 haplotypes showing variability in the extended HLA-DRB1 haplotype structures. On the contrary, BTNL2 block and HLA-DQB1 were more conserved showing linkage with the HLA-DRB1 alleles. We show that the use of HLA-DRB1 haplotypes rather than single HLA-DRB1 alleles is advantageous when studying the polymorphisms and LD patters of the MHC region. For disease association studies the HLA-DRB1 haplotypes with various MHC markers allows us to cluster haplotypes with functionally important gene variants such as C4 deficiency and cytokines TNF and LTA, and provides hypotheses for further assessment. Our study corroborates the importance of studying population-specific MHC haplotypes.
PMCID: PMC3836878  PMID: 24278156
21.  The Major Histocompatibility Complex Class II Alleles Mamu-DRB1*1003 and -DRB1*0306 Are Enriched in a Cohort of Simian Immunodeficiency Virus-Infected Rhesus Macaque Elite Controllers▿  
Journal of Virology  2007;82(2):859-870.
The role of CD4+ T cells in the control of human immunodeficiency virus (HIV) and simian immunodeficiency virus (SIV) replication is not well understood. Even though strong HIV- and SIV-specific CD4+ T-cell responses have been detected in individuals that control viral replication, major histocompatibility complex class II (MHC-II) molecules have not been definitively linked with slow disease progression. In a cohort of 196 SIVmac239-infected Indian rhesus macaques, a group of macaques controlled viral replication to less than 1,000 viral RNA copies/ml. These elite controllers (ECs) mounted a broad SIV-specific CD4+ T-cell response. Here, we describe five macaque MHC-II alleles (Mamu-DRB*w606, -DRB*w2104, -DRB1*0306, -DRB1*1003, and -DPB1*06) that restricted six SIV-specific CD4+ T-cell epitopes in ECs and report the first association between specific MHC-II alleles and elite control. Interestingly, the macaque MHC-II alleles, Mamu-DRB1*1003 and -DRB1*0306, were enriched in this EC group (P values of 0.02 and 0.05, respectively). Additionally, Mamu-B*17-positive SIV-infected rhesus macaques that also expressed these two MHC-II alleles had significantly lower viral loads than Mamu-B*17-positive animals that did not express Mamu-DRB1*1003 and -DRB1*0306 (P value of <0.0001). The study of MHC-II alleles in macaques that control viral replication could improve our understanding of the role of CD4+ T cells in suppressing HIV/SIV replication and further our understanding of HIV vaccine design.
PMCID: PMC2224575  PMID: 17989178
22.  Increase of HLA-DRB1*0408 and -DQB1*0301 in HLA-B27 positive reactive arthritis 
OBJECTIVE—To study HLA class II association in reactive arthritis.
METHODS—63 patients with reactive arth-ritis and 46 with rheumatoid arthritis were included in the study. HLA-DR alleles were determined by using a sequence specific PCR method. Oligonucleotide hybridisation was used for definition of DRB1*04 subtypes and DQB1 alleles. HLA-B27 was determined by standard microcytotoxity test or by PCR. HLA-B27 subtyping was made by sequencing.
RESULTS—46 (73%) of 63 patients with reactive arthritis were HLA-B27 positive and 24 (38%) were HLA-DRB1*04 positive. When haplotypes were inferred according to the known associations between DRB1 and DQB1 alleles, the frequency of DRB1*04-DQB1*0301 haplotype was found to be 13% (12/92) in HLA-B27 positive reactive arthritis patients, in contrast to 0% in HLA-B27 negative reactive arthritis (P = 0.04) and 1% in random controls (P = 0.0009). However, this combination was also found in 5% of 84 HLA-B27 positive control haplotypes, showing a linkage disequilibrium between B27 and this particular class II haplotype. HLA-DRB1*0408 subtype was found in 8/24 (33%) of the HLA-DRB1*04 alleles in patients with reactive arthritis, accounting for most DQB1*0301 haplotypes, but only in 5/55 (9%) of the DRB1*04 alleles in random controls (P = 0.017). All reactive arthritis patients with this subtype were positive for HLA-B27. DRB1*04-DQB1*0302 haplotype was increased in patients with rheumatoid arthritis (28/92, 30%) compared with reactive arthritis (12/126, 10%) or with the controls (12/100, 12%; P = 0.003). HLA-B*2705 was by far the dominant B27 subtype both in reactive arthritis patients with the particular DRB1*0408-DQB1*0301 haplotype and in controls. It was found in 11 out of 12 DR analysed patients, as well as in 10 out of 11 randomly selected B27 positive controls.
CONCLUSIONS—Although no single class II allele was found to be increased among patients with reactive arthritis, HLA-B27, DRB1*0408, and DQB1*0301 might exert a haplotypic effect in the pathogenesis of reactive arthritis, or they may be markers of a subset of B27 haplotypes conferring susceptibility.

PMCID: PMC1752258  PMID: 9059139
23.  Clinical, immunological, and immunogenetic aspects of autoantibody production against Ro/SSA, La/SSB and their linear epitopes in primary Sjögren's syndrome (pSS): a European multicentre study 
Annals of the Rheumatic Diseases  2002;61(5):398-404.
Objectives: To investigate the clinical and immunogenetic aspects of antibody formation against Ro/SSA and La/SSB as well as their linear B cell epitopes in patients with primary Sjögren's syndrome (pSS) from different European countries.
Patients and methods: Ninety patients with pSS from six European centres were studied. Serum samples from all patients were tested in a control laboratory for anti-Ro/SSA and anti-La/SSB autoantibodies by RNA precipitation assay and autoantibodies to the previously reported B cell linear epitopes of Ro 60 kDa (p169–190aa and p211–232aa) and La/SSB (p147–154aa, p291–302aa, p301–318aa, and p349–364aa). DNA from 88 patients was used for the determination of HLA-DRB1, -DQA1, and -DQB1 genotypes. Analysis of the results was performed in the 88 patients who were genotyped and tested also for antipeptide antibodies.
Results: Antibodies to B cell epitopes of Ro 60 kDa were detected at a low frequency (range 10–37%). In contrast, B cell epitopes of La/SSB were detected frequently (range 58–86%) among the anti-La/SSB positive sera. Autoantibodies to the La/SSB epitope, p349–364aa, were significantly positively associated with longer disease duration (p<0.05), recurrent or permanent parotid gland enlargement (p<0.005), and a higher proportion of non-exocrine manifestations (p<0.005), compared with patients without autoantibodies. The presence of anti-Ro/SSA and anti-La/SSB autoantibodies was significantly associated with the presence of HLA-DRB1*03 and DQB1*02 (p=0.038 and p=0.034, respectively). This association was even more prominent and extended to HLA-DQA1*0501 when patients were stratified according the presence of autoantibodies to discrete La/SSB B cell epitopes in comparison with autoantibody negative patients (p<0.01). They were found also to be highly associated with the alleles HLA-DQB1*02 and HLA-DQA1*0501 as well as the presence of a shared amino acid motif in the region 59–69aa of DQB1 first domain (p<0.01, respectively).
Conclusions: Autoantibodies against La/SSB, binding to four synthetic peptides, derived from the sequence of the La protein were identified with increased frequency in sera of patients with pSS. The formation of autoantibodies against B cell epitope analogues of La/SSB in European patients with pSS may be dependent on the presence of a permissive HLA-DQ heterodimer, most prominently represented by the HLA-DQA1*0501/DQB1*0201 heterodimer, suggesting that a model of HLA restricted presentation of La/SSB peptide determinants is crucial for the autoimmune response against La/SSB.
PMCID: PMC1754090  PMID: 11959762
24.  Human leukocyte antigen class I and class II alleles are associated with susceptibility and resistance in borderline leprosy patients from Southeast Brazil 
Evidence suggests that human leukocyte antigen (HLA) alleles influence the host immune response against Mycobacterium leprae. However, the association between HLA alleles and borderline (B) leprosy has not been studied. The aim of this study was to determine whether HLA class I and II molecules are associated with susceptibility or resistance to B leprosy including borderline-tuberculoid (BT), borderline-borderline (BB), and borderline-lepromatous (BL).
DNA was obtained by the salting-out technique from the blood samples of 202 patients with B leprosy and 478 control subjects. HLA class I (A*, B*, and C* loci) and class II (DRB1* and DQB1* loci) genotypes were determined by polymerase chain reaction amplification and reverse hybridization with sequence-specific oligonucleotide probes and sequence-specific primers.
The case-controlled analysis results showed a significant association between B leprosy and HLA-C*05 (5.94% vs. 14.02%; p = 0.002, OR = 0.38, 95% CI = 0.20–0.73, pc = 0.032) and HLA-DRB1*07 (16.34% vs. 26.77%; p = 0.003, OR = 0.53, 95% CI = 0.3–0.8, pc = 0.039). A protective association was observed between BL leprosy and HLA-DQB1*02 (18.18% vs. 39.53%; p = 0.005, OR = 0.34, 95% CI = 0.15–0.75, pc = 0.025). In reactional patients, a significant association was observed between HLA-B*15 (28.72% vs. 12.76%; p = 0.011, OR = 2.75, 95% CI = 1.30–5.85, pc = 0.352) and predisposition to reversal reaction. Haplotype analysis showed that A*02-B*07-C*07-DRB1*15-DQB1*06 (2.97% vs. 1.04%; p = 0.015) and A*02-B*40-C*03-DRB1*13-DQB1*06 (1.73% vs. 0.10%; p = 0.0011) were associated with susceptibility to the B form. The presence of the HLA-DRB1*02 or HLA-DRB1*03/HLA-DQB1*01 haplotypes in B patients (22.05% vs. 33.0%; p = 0.005) suggested the involvement of these haplotypes in this clinical form of the disease.
The results indicate the involvement of HLA class I and class II molecules in B leprosy and reversal reactions; it also suggest a role for HLA in polarization of the disease in this group of patients.
Electronic supplementary material
The online version of this article (doi:10.1186/s12879-015-0751-0) contains supplementary material, which is available to authorized users.
PMCID: PMC4307149  PMID: 25605482
Leprosy; Borderline; HLA alleles; Genetics; Mycobacterium leprae
25.  High-Density SNP Mapping of the HLA Region Identifies Multiple Independent Susceptibility Loci Associated with Selective IgA Deficiency 
PLoS Genetics  2012;8(1):e1002476.
Selective IgA deficiency (IgAD; serum IgA<0.07 g/l) is the most common form of human primary immune deficiency, affecting approximately 1∶600 individuals in populations of Northern European ancestry. The polygenic nature of IgAD is underscored by the recent identification of several new risk genes in a genome-wide association study. Among the characterized susceptibility loci, the association with specific HLA haplotypes represents the major genetic risk factor for IgAD. Despite the robust association, the nature and location of the causal variants in the HLA region remains unknown. To better characterize the association signal in this region, we performed a high-density SNP mapping of the HLA locus and imputed the genotypes of common HLA-B, -DRB1, and -DQB1 alleles in a combined sample of 772 IgAD patients and 1,976 matched controls from 3 independent European populations. We confirmed the complex nature of the association with the HLA locus, which is the result of multiple effects spanning the entire HLA region. The primary association signal mapped to the HLA-DQB1*02 allele in the HLA Class II region (combined P = 7.69×10−57; OR = 2.80) resulting from the combined independent effects of the HLA-B*0801-DRB1*0301-DQB1*02 and -DRB1*0701-DQB1*02 haplotypes, while additional secondary signals were associated with the DRB1*0102 (combined P = 5.86×10−17; OR = 4.28) and the DRB1*1501 (combined P = 2.24×10−35; OR = 0.13) alleles. Despite the strong population-specific frequencies of HLA alleles, we found a remarkable conservation of these effects regardless of the ethnic background, which supports the use of large multi-ethnic populations to characterize shared genetic association signals in the HLA region. We also provide evidence for the location of association signals within the specific extended haplotypes, which will guide future sequencing studies aimed at characterizing the precise functional variants contributing to disease pathogenesis.
Author Summary
The human leukocyte antigen (HLA) locus is robustly associated with many immune-mediated conditions. However, identification of the genetic variants contributing to the disease pathophysiology has been greatly hampered by the extensive chromosomal conservation within this genomic region. To better understand the association of the HLA locus in selective IgA deficiency (IgAD), we used an extensive genotyping database from a recent genome-wide association study (GWAS) to generate a high-density SNP map of this region in a combined sample of >2,700 individuals from 3 independent European populations. In addition, we took advantage of recent methodological advances to impute the more common HLA-B, -DRB1, and -DQB1 alleles in all subjects. We confirmed the strong disease-association of the HLA locus and identified several different signals located in specific conserved HLA haplotypes contributing independent risk or protection for IgAD. Further analysis of the chromosomal sequences associated with the associated HLA alleles allowed us to refine the mapping of the susceptibility variants. These findings represent the most comprehensive high-density SNP mapping of the HLA locus in IgAD to date and provide important new information as to the location of the genetic variants contributing to this common immune deficiency.
PMCID: PMC3266887  PMID: 22291608

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