HLA-DRB1 genes and disease severity in rheumatoid arthritis in Turkey

Association of rheumatoid arthritis and its severity with human leukocytic antigen-DRB1 alleles in Kurdish region in North of Iraq

BACKGROUND

Rheumatoid arthritis is a complex multifactorial chronic disease, the importance of human leukocytic antigen (HLA) as a major genetic risk factor for rheumatoid arthritis was studied worldwide. The objective of this study is to identify the association of HLA-DRB1 subtypes with rheumatoid arthritis and its severity in Kurdish region.

METHODS

A case-control study recruited 65 rheumatoid arthritis patients and 100 healthy individuals as control group all over the Kurdistan region/Iraq. Both patient and control groups are genotyped using polymerase chain reaction with sequence specific primer. Anti-CCP antibodies were measured by ELISA test. Rheumatoid factor, C-reactive protein, and disease activity score 28 which measured by DAS-28 values were calculated. The DAS-28 was used to assess the clinical severity of the patients.

RESULTS

HLA-DRB1-0404 and HLA-DRB1-0405 frequencies showed a strong association with disease susceptibility (P < 0.001). The frequency of HLA-DRB1-0411 and HLA-DRB1-0413 were significantly higher in control group (P < 0.001). The frequency of rheumatoid factor and Anti-CCP were significantly higher among shared epitope-positive patients compared to shared epitope-negative patients (P < 0.001). Regarding the disease activity by DAS-28, rheumatoid arthritis patients didn't show significant difference between the shared epitope-positive and shared epitope-negative patients.

CONCLUSIONS

HLA-DR0404 and HLA-DR0405 alleles are related to RA, while HLA-DR1-0411 and HLA-DRB1-0413 protect against RA in the Kurdistan region in the North of Iraq.

Association of biomarkers of inflammation and HLA-DRB1 gene locus with risk of developing rheumatoid arthritis in females

Rheumatoid arthritis (RA) is an autoimmune disease causing chronic inflammation of the joints. Multiple factors, including HLA-DRB1 gene variants, influence the susceptibility to RA. The HLA-DRB1 gene is part of a family of genes called the human leukocyte antigen (HLA) complex. In this study, we compared the inflammatory biomarkers values, including erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP), between patients with RA and healthy control group of females of the Public Institution Health Centre of Sarajevo Canton. In addition, we estimated the frequencies of the HLA-DRB1 gene variants and their association with the risk for RA development in females. The haematological and biochemical tests were completed on automated analyzers. To assess the association between the HLA-DRB genes and the risk of RA in females, low-resolution genotyping of the HLA-DRB1, DRB3, DRB4, and DRB5 gene loci was performed by the sequence-specific polymerase chain reaction method (PCR-SSP). ESR and CRP were the most sensitive acute-phase reactants in females with RA and there was a correlation between ESR and CRP values in RA patients. There was significantly positive association between of the HLA-DRB1*03, *04, *08, *10, *11, and *14 variants and elevated values of ESR in RA patients, but negative between HLA-DRB1*03, *13 and *15 alleles and elevated CRP values. Furthermore, our results confirm genetic susceptibility to RA in a female population to the members of the HLA-DRB1*04 and *03 allelic groups, the DRB1*04/DRB1*04 and DRB1*03/DRB1*04 genotypes, and the DRB1*04-DRB4* or DRB1*03-DRB3* haplotypes, which, therefore, represent risk factors for the development of this disease. According to our results, the DRB1*01/DRB1*15 and DRB1*07/DRB1*16 genotypes and the HLA-DRB5 gene locus represent a protective factor for RA. The presence of specific HLA-DRB1 gene variants increases the risk of developing RA, while other variants provide protection against disease. Therefore, HLA typing could be helpful in the prediction of RA development and establishing and confirming a definitive diagnosis of autoimmune diseases in some subjects. A strong association with the higher levels of ESR and CRP could be used to establish definitive diagnosis and introduce of early treatment of RA to prevent the occurrence of RA symptoms.

Crosslinks Between Human Leukocyte Antigen DRB1*01 and Human Leukocyte Antigen DRB1*13 Allelic Variants and Occurrence of Rheumatoid Arthritis in Patients From Federation of Bosnia and Herzegovina

Objectives

This study aims to analyze human leukocyte antigen A (HLA-A), human leukocyte antigen B (HLA-B), human leukocyte antigen C (HLA-C), HLA-DRB1*, HLA-DRB3*, HLA-DRB4*, HLA-DRB5*, HLA-DQB1* loci expression in patients with rheumatoid arthritis (RA) in the Federation of Bosnia and Herzegovina.

Patients and methods

Deoxyribonucleic acid was isolated from peripheral blood of 48 RA patients (22 males, 26 females; mean age 36 years; range 2 to 63 years) and 104 healthy control individuals (52 males, 52 females; mean age 43 years; range 2 to 76 years). Deoxyribonucleic acid samples were analyzed using polymerase chain reaction-sequence-specific primers and sequence specific oligonucleotides methods.

Results

The most frequent allelic groups in RA patients were HLA-DRB1*01 (odds ratio=2.795; 95% confidence interval: 1.441-5.421; p=0.004) and HLA-DRB1*04 (odds ratio=2.573; 95% confidence interval: 1.214-5.453; p=0.023). Among RA patients, the most frequent genotype for the allelic group HLA-DRB1*, in the light of the common epitopes theory, was observed for DRB1*01/DRB1*13. This genotype indicates an increased incidence and relative risk (odds ratio=11.09).

Conclusion

The most common genotype in our RA patients was DRB1*01/DRB1*13, which showed increased frequency and a high relative risk. This genotype variant may be considered a predisposing factor for the development of RA.

TMEM187-IRAK1 Polymorphisms Associated with Rheumatoid Arthritis Susceptibility in Tunisian and French Female Populations: Influence of Geographic Origin

Polymorphisms have been identified in the Xq28 locus as risk loci for rheumatoid arthritis (RA). Here, we investigated the association between three polymorphisms in the Xq28 region containing TMEM187 and IRAK1 (rs13397, rs1059703, and rs1059702) in two unstudied populations: Tunisian and French. The rs13397 G and rs1059703 T major alleles were significantly increased in RA patients (n = 408) compared with age-matched controls (n = 471) in both Tunisian and French women. These results were confirmed by a meta-analysis replication study including two independent Greek and Korean cohorts. The rs1059702 C major allele was significantly associated with RA, only with French women. In the French population, the GTC haplotype displayed a protective effect against RA, while the ATC, GCC, and GTT haplotypes conferred significant risk for RA. No association for these haplotypes was found in the Tunisian population. Our results replicated for the first time the association of the three Xq28 polymorphisms with RA risk in Tunisian and French populations and suggested that RA susceptibility is associated with TMEM187-IRAK1 polymorphisms in women. Our data further support the involvement of X chromosome in RA susceptibility and evidence ethnicities differences that might be explained by differences in the frequencies of SE HLA-DRB1 alleles between both populations.

Genetic Predisposition to Rheumatoid Arthritis in a Tuscan (Italy) Ancient Human Remain

Rheumatoid arthritis (RA) is currently believed to have originated in America, and after the discovery of this continent in 1492, to have been exported to the Old World. We evaluated the genetic predisposition to RA in the “Braids Lady” from Arezzo (Italy), a partially mummified woman's body dating back to the end of 1500 AD which presents the anatomical and pathological features of this disease. The study of the polymorphic HLA-DRB1 locus, which includes alleles strongly associated with RA onset, has received much attention over recent years, especially the loci codifying for the DR1 and DR4 antigens, widely represented in the Mediterranean population, and for DR14, widespread among Native Americans. Molecular analysis was performed on extracts of DNA from the mummy, firstly from histological bone sections and then from the whole bone. Two different HLA typing techniques, PCR-sequence-specific oligonucleotides (PCR-SSO) and PCR-sequence-specific primers (PCR-SSP), were employed to identify HLA-DRB alleles. Both genotyping methods showed that the “Braids Lady” carried the DRB1*0101 allele, the serological equivalent of the DR1 antigen. Although the possession of RA risk factor genes cannot be considered a diagnostic marker, the positive result of the Italian mummy for DRB1*0101 and the RA features present, support the idea that this pathology was present in the Old World from at least the mid-16th century. A pathogenetic hypothesis of RA which might well explain its worldwide diffusion is the “molecular mimicry”, resulting from a cross-reactive antibody response between certain microbial antigens and shared epitopes of specific HLA-DR1, DR4 and DR14 susceptibility alleles, the frequency of which varies among different ethnic groups.

Association of HLA-DRB1 amino acid residues with giant cell arteritis: genetic association study, meta-analysis and geo-epidemiological investigation

INTRODUCTION

Giant cell arteritis (GCA) is an autoimmune disease commonest in Northern Europe and Scandinavia. Previous studies report various associations with HLA-DRB1*04 and HLA-DRB1*01; HLA-DRB1 alleles show a gradient in population prevalence within Europe. Our aims were (1) to determine which amino acid residues within HLA-DRB1 best explained HLA-DRB1 allele susceptibility and protective effects in GCA, seen in UK data combined in meta-analysis with previously published data, and (2) to determine whether the incidence of GCA in different countries is associated with the population prevalence of the HLA-DRB1 alleles that we identified in our meta-analysis.

METHODS

GCA patients from the UK GCA Consortium were genotyped by using single-strand oligonucleotide polymerization, allele-specific polymerase chain reaction, and direct sequencing. Meta-analysis was used to compare and combine our results with published data, and public databases were used to identify amino acid residues that may explain observed susceptibility/protective effects. Finally, we determined the relationship of HLA-DRB1*04 population carrier frequency and latitude to GCA incidence reported in different countries.

RESULTS

In our UK data (225 cases and 1378 controls), HLA-DRB1*04 carriage was associated with GCA susceptibility (odds ratio (OR) = 2.69, P = 1.5×10(-11)), but HLA-DRB1*01 was protective (adjusted OR = 0.55, P = 0.0046). In meta-analysis combined with 14 published studies (an additional 691 cases and 4038 controls), protective effects were seen from HLA-DR2, which comprises HLA-DRB1*15 and HLA-DRB1*16 (OR = 0.65, P = 8.2×10(-6)) and possibly from HLA-DRB1*01 (OR = 0.73, P = 0.037). GCA incidence (n = 17 countries) was associated with population HLA-DRB1*04 allele frequency (P = 0.008; adjusted R(2) = 0.51 on univariable analysis, adjusted R(2) = 0.62 after also including latitude); latitude also made an independent contribution.

CONCLUSIONS

We confirm that HLA-DRB1*04 is a GCA susceptibility allele. The susceptibility data are best explained by amino acid risk residues V, H, and H at positions 11, 13, and 33, contrary to previous suggestions of amino acids in the second hypervariable region. Worldwide, GCA incidence was independently associated both with population frequency of HLA-DRB1*04 and with latitude itself. We conclude that variation in population HLA-DRB1*04 frequency may partly explain variations in GCA incidence and that HLA-DRB1*04 may warrant investigation as a potential prognostic or predictive biomarker.

HLA-DRB1 frequency in patients with familial and sporadic rheumatoid arthritis in north east of Iran

Rheumatoid arthritis (RA) is a chronic inflammatory disease of the joints that has a strong correlation with HLA-DRB1. Family history is considered a known risk factor for RA. The aims of this study were to compare the frequency of HLA-DRB1 alleles between patients with sporadic and familial RA and also between healthy controls with RA patients (sporadic and familial) and clarify if familial RA is more severe than sporadic RA. This study included 129 consecutive patients with sporadic and 48 cases with familial (first-degree siblings) RA who visited a rheumatology unit. Demographic data, including extra-articular involvement, mean disease activity according to DAS28 (ESR) criteria, and main laboratory findings, were compared between patients with sporadic and familial RA. HLA-DRB1 typing was carried out using the PCR-SSP method, and the frequency of each allele was determined in all cases and compared with the results of HLA-DRB1 frequencies in 72 healthy controls who were previously reported by our group in northeast Iran. Patients with sporadic and familial RA were matched in age and sex, most of the cases in both groups were females. The mean age of patients was 45 years. Ocular involvement was the most frequent extra-articular manifestation of our patients. There was no significant difference between the two groups in visual analogue scale (VAS) index, number of inflamed or tender joints, extra-articular involvements, and main laboratory findings. HLA-DRB1* 01 (55 %), 04 (48 %), and 03 (43 %) alleles were the most frequent alleles in both sporadic and familial diseases. The frequency of HLA-DRB1*11 and HLA-DRB1*13 was significantly higher in normal participants compared with RA (p = 0.001). There was no significant difference in the HLA-DRB1 allele's frequency between sporadic and familial RA. Therefore, familial aggregation was not associated with RA severity.

Shared epitope and radiologic progression are less prominent in elderly onset RA than young onset RA

The aim of this study was to determine the influence of HLA-DRB1 and HLA-DQB1 genes on the disease susceptibility and the disease severity in elderly onset rheumatoid arthritis (EORA) compared with young onset rheumatoid arthritis (YORA) in Korean patients. Genetic analysis of HLA-DRB1 and HLA-DQB1 alleles was performed in three groups. Group 1 included 63 patients who were diagnosed with (rheumatoid arthritis) RA after the age of 60 (EORA). Group 2 consisted of 109 patients who were diagnosed with RA before the age of 60 (YORA). Group 3 involved 133 normal controls. The shared-epitope-coding alleles included the members of the HLA-DRB1*04 allele group (*0401, *0404, *0405, *0408, *0410), HLA-DRB1*01 allele group (*0101,*0102), HLA-DRB1*1001, and HLA-DRB1*1402. The disease severity was assessed by the modified total sharp score (mTSS). The shared-epitope-coding alleles were more frequently observed in the RA patients than in the normal controls. The shared-epitope-coding alleles were less frequently found in EORA group than YORA group (31/63 (49.2%) in group 1, 72/109 (66.1%) in group 2, 45/133 (33.8%) group 3, p = 0.02). Although the mTSS of the group 1 was higher than group 2 at symptom onset, the overall mean mTSS of the group 1 was lower than that of group 2 (26.8 vs. 57.5, p < 0.05). HLA-DQ*04 showed the higher frequency in the patients group than in normal controls (p < 0.001). And HLA-DQ*04 was less commonly found in the patients with EORA than YORA (p < 0.05). The influence of shared epitope and HLA-DQ*04 alleles may be less significant on disease susceptibility in EORA. The presence of shared-epitope-coding alleles did not appear to influence on disease severity in EORA patients as well as in YORA patients. Radiologic deterioration in EORA group was less severe than in YORA group. The presence of shared epitope and radiologic progression are less prominent in EORA patients than YORA patients.

Association of HLA genes with clinical outcomes of ANCA-associated vasculitis

BACKGROUND AND OBJECTIVES

The HLA system plays a central role in the distinction between self antigens and non-self antigens. This study aimed to investigate the association between HLA genes and the outcomes of patients with ANCA-associated vasculitis (AAV).

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This study recruited 152 consecutive Chinese patients with AAV. The predictive value of the HLA alleles for renal outcome, response to treatment, and all-cause mortality were analyzed.

RESULTS

The proportion of patients with treatment failure was significantly higher in DRB1*0405-positive patients than in DRB1*0405-negative patients (41.7% versus 12.9%; P=0.008; corrected P=0.02). After adjusting for the other potential predictors, DRB1*0405 was still an independent predictor for the poor response to treatment (hazard ratio [HR], 5.91; 95% confidence interval [95% CI], 1.23-28.52; P=0.03). Renal survival was significantly worse in patients with DRB1*0405 than those without DRB1*0405 (P<0.001; corrected P<0.001). After adjusting for the other potential predictors, DRB1*0405 was still an independent predictor for ESRD (HR, 5.50; 95% CI, 2.18-13.88; P<0.001). The probability of all-cause mortality in patients with DPB1*0402 was significantly higher than those without DPB1*0402 (P=0.02; corrected P=0.04). After adjusting for the other potential predictors, DPB1*0402 was still an independent predictor for all-cause mortality (HR, 2.52; 95% CI, 1.21-5.28; P=0.01).

CONCLUSIONS

In AAV patients, DRB1*0405 might be an independent risk factor for the poor response to treatment and the deterioration of renal function, whereas DPB1*0402 might be an independent risk factor for all-cause mortality.

Association study of human leukocyte antigen-DRB1 alleles with rheumatoid arthritis in south Tunisian patients

The aim of this study is to explore relationship between HLA-DRB1 alleles and the susceptibility and clinical features of rheumatoid arthritis (RA) in the south Tunisian population. We studied 142 RA patients and 123 controls matched for age, sex, and ethnicity. HLA-DRB1 genotyping and HLA-DRB1*04 subtypes were performed using polymerase chain reaction/sequence-specific primers. Association was assessed based on the χ (2) test and odds ratio with 95% confidence interval. For multiple comparisons, p value was corrected (p (c)) with Bonferroni test. Two alleles, HLA-DRB1*04 (p=0.045, p(c)=NS) and HLA-DRB1*10 (p=0.021, p(c)=NS), were found to have increased frequencies in RA patients compared to controls. In contrast HLA-DRB1*08 allele was found to have a decreased frequency in patients compared to controls (p=0.044, p(c)=NS). Molecular subtyping of the most prevalent allele (DRB1*04) revealed increased frequencies of HLA-DRB1*04:05 in patients compared to controls (p=0.013, p(c)=NS) whereas HLA-DRB1*04:02 showed a protective effect (p=0.005, p(c)=0.04). Moreover, stratified analyses indicated statistically significant associations between HLA-DRB1*04 allele and anti-cyclic peptides antibodies positivity (ACPA(+)) and rheumatoid factor positivity (RF(+); p(c)=0.03, for both subgroups), HLA-DRBI*10 and ACPA(+) and the presence of another autoimmune disease (p(c)=0.05 and p(c)=0.007, respectively), and HLA-DRB1*04:05 and RF(+) and erosion (p(c)=0.005 and p(c)=0.049; respectively). A significant decrease in the frequency of the DRB1*04:02 allele was observed in patients with ACPA(+) and RF(+) subgroups (p(c)=0.04 and p(c)=0.02, respectively). Our results showed that there was a trend of positive association of HLA-DRB1*04 and HLA-DRB1*10 with RA as such and significant associations with the disease severity in the south Tunisian population.

Associations of HLA-DRB1 alleles with anti-citrullinated protein antibody-positive and anti-citrullinated protein antibody-negative rheumatoid arthritis in northern east part of Turkey

AIM

The aim of this study was to investigate the associations between human leukocyte antigen (HLA)-DRB1 alleles with genetic susceptibility to rheumatoid arthritis (RA) and production of antibodies against cyclic citrullinated peptide (anti-CCP antibody) and rheumatoid factor (RF) in Turkish RA patients.

METHODS

We studied 291 RA patients and 253 controls. Genotyping was performed by polymerase chain reaction with sequence-specific oligonucleotide probes hybridization method. Serum levels of anti-CCP antibody, IgM-RF and high sensitive C-reactive protein titers were measured by commercial kits using immunological methods.

RESULTS

We found that HLA-DRB1*04 and *09 alleles were associated in anti-CCP+ and anti-CCP+ RA patients (P < 0.0001 and P < 0.001, respectively), while DRB1*01 and *04 were determined to be higher in RF+ RA patients (P < 0.001 and P < 0.0001, respectively). Moreover, DRB1*11 and DRB1*13 alleles were determined to be lower in RF and anti-CCP/RF+ RA patients (P < 0.001 for both). HLA-DRB1*04 was identified as a common responsible allele for susceptibility to the disease in anti-CCP, RF and anti-CCP/RF- RA patients (P = 0.0018, P = 0.0004 and P = 0.0023, respectively). HLA-DRB1*13 allele alone was found to be protective against to anti-CCP+ and RF- RA (P = 0.0003 and P = 0.006, respectively). On the contrary, there was no protective allele in anti-CCP/RF- RA as well as anti-CCP- RA patients.

CONCLUSION

This study indicates that associate and protective HLA-DRB1 allele distributions are different in autoantibody (anti-CCP or RF or anti-CCP/RF)+ RA and autoantibody- RA patients, with exceptions of DRB1*04 and DRB1*13.

HLA-DRB1 allele distribution and its relation to rheumatoid arthritis in eastern Black Sea Turkish population

Rheumatoid arthritis (RA [MIM 180300]) is a complex, polygenic inflammatory autoimmune disease, resulting from interactions between genetic and environmental factors. Some of the RA-associated HLA-DRB1 alleles have shared epitope, but their distribution varies among different racial/ethnic groups. This study was aimed at investigating the distribution of HLA-DRB1 alleles in patients with RA in eastern Black Sea region of Turkey. DNA samples of 320 patients with RA and 360 healthy controls were studied for the determination of HLA-DRB1 allele distribution using PCR-SSP method. The allele frequencies of HLA-DRB1*01, *04, and *09 were higher in patients with RA compared with the controls (P < 0.005, P < 0.0001, and P < 0.01, respectively). On the other hand, in patients with RA, HLA-DRB1*13 allele was lower than the controls (P < 0.001). Of the HLA-DRB1*04 subgroups, *0401 (40.83% vs. 18.75%, P < 0.001) was the most frequent allele in patients with RA, while DRB1*0402 (30.00% vs. 12.50%, P < 0.005) allele in the controls. HLA-DRB1 allele frequencies in the patients with RA and the controls showed Hardy-Weinberg rule compliance. Results of this study indicate that HLA-DRB1*01, *04, and *09 alleles were associated with RA, and HLA-DRB1*13 was protective allele against RA. Among the subgroups of HLA-DRB1*04, *0401 was detected to be RA associated, while *0402 was being protective. These results have some differences compared with previous reports originating from other regions of Turkey.

The association of HLA-DRB1 alleles with rheumatoid arthritis in the Chinese Shantou population: a follow-up study

We investigated the distribution of HLA-DRB1 alleles in a sample of the Chinese Shantou population, and explored the relationship between HLA-DRB1 alleles and the susceptibility and clinical features of rheumatoid arthritis (RA). We studied 117 consecutive patients with RA and control groups, including 38 cases of systemic lupus erythematosus and 100 healthy individuals. HLA-DRB1 genotyping was performed using PCR with sequence-specific primers. HLA-DRB1*04 subtypes were detected using spot hybridization of PCR products with sequence-specific oligonucleotide probes. We compared the frequency of HLA-DRB1 alleles in healthy control patients with that in patients with RA. Patients with RA were evaluated for sex, age at disease onset, disease duration, extra-articular involvement, presence of autoantibodies, global functional status, and radiographic damage. The frequency of HLA-DRB1*04 was found to be significantly higher in RA patients than in healthy individuals (49.6% vs 18.0%, odds ratio = 4.478, P < 0.001). HLA-DRB1*0405 was the most prominently associated subtype in RA patients (62.1% vs 27.8%, odds ratio = 4.255, P = 0.011). Compared with the HLA-DRB1*04-negative RA group, the mean duration of RA in the HLA-DRB1*04-positive RA group was longer, and the mean age at disease onset was lower. A 2-9 year follow-up study was performed, and the risk factors associated with the radiographic progression of RA were determined. Logistic regression analysis revealed that only HLA-DRB1*04 alleles were significantly associated with the radiographic progression of RA (B = 2.652, P = 0.018, Exp(B) = 14.182). Our observations indicated that the HLA-DRB1*04 alleles, especially the subtype HLA-DRB1*0405, were significantly associated with RA susceptibility in the Chinese Shantou population. The HLA-DRB1*04 alleles may be associated with the severity of RA.

HLA-DRB1 association in Saudi rheumatoid arthritis patients

Association between HLA-DRB1 alleles and rheumatoid arthritis (RA) has been known for more than three decades. However, the strength of these links varies between ethnic groups. This study examines the frequency of HLA-DRB1 alleles amongst Saudi RA patients. The DRB1 region of major histocompatibility complex was screened by polymerase chain reaction/sequence specific primers (PCR/SSP) in a total of 140 subjects including 70 RA patients and 70 matched healthy controls. HLA-DRB1 *04 was found to be the most frequent allele associated with RA followed by DRB1 *08 and DRB1 *10. On the other hand, the frequency of DRB1*06 was found to be decreased in RA patients as compared to controls. Molecular sub typing of the most prevalent allele DRB1 *04 revealed a statistically significant association between RA and DRB1 *0405. We conclude that an improved understanding about the influence of HLA on RA might help in predicting the susceptibility or protection against disease.

HLA and disease

Association of HLA and diseases is well known. Several population studies are available suggesting evidence of association of HLAs in more than 40 diseases. HLA found across various populations vary widely. Some of the reasons attributed for such variation are occurrence of social stratification based on geography, language and religion, consequences of founder effect, racial admixture or selection pressure due to environmental factors. Hence certain HLA alleles that are predominantly associated with disease susceptibility or resistance in one population may or may not show any association in other populations for the same disease. Despite of these limitations, HLA associations are widely studied across the populations worldwide and are found to be important in prediction of disease susceptibility, resistance and of evolutionary maintenance of genetic diversity. This review consolidates the HLA data on some prominent autoimmune and infectious diseases among various ethnic groups and attempts to pinpoint differences in Indian and other population.

Human leukocyte antigen DRB1*04 is associated with rheumatoid arthritis in Kuwaiti patients

OBJECTIVES

Rheumatoid arthritis (RA) is a common, complex autoimmune disease known to be associated with inheritance of certain human leukocyte antigen (HLA)-DR alleles in different populations. This study investigated the association of DRB1 alleles in Kuwaiti patients with RA.

MATERIALS AND METHODS

DRB1 alleles were analyzed in 47 Kuwaiti patients and 70 ethnically matched controls using a DNA-based sequence specific primer (SSP) method.

RESULTS

The frequency of DRB1*04 allele was higher in patients compared to the controls (P < 0.012). The association with of HLA-DRB1*04 allele in our patients with RA was accounted for mainly by the seropositive group of patients (P < 0.05). Moreover, five patients were homozygous for DRB1*4 compared to none in the controls. None of the other DRB1 alleles tested was significantly higher in the patients. All patients homozygous for the DRB1*04 allele were females. There was no statistically significant difference in the frequency of DRB1*04 allele in patients classified according to presence of erosive disease or extra-articular manifestations.

CONCLUSION

Our results indicate that in Kuwaiti patients, RA is associated with the presence of DRB1*04 allele. The lack of association with severity or the phenotype of RA is not surprising since this is a hospital-based study where patients tend to have a more severe disease.