Associative role of HLA‐DRB1 SNP genotypes as risk factors for susceptibility and severity of rheumatoid arthritis: A North‐east Indian population‐based study

Rheumatoid arthritis (RA) is a complex, multifactorial, systemic autoimmune disease. Reports are suggestive of the role of HLA especially HLA‐DRB1 alterations in RA pathogenesis. Existing data involving different geographical populations on the role of alterations in specific locus of HLA‐DRB1 in RA susceptibility and severity are equivocal, with no data available from ethnically distinct North‐east Indian population, where RA cases are alarmingly increasing. This study aimed to evaluate the association of HLA‐DRB1 gene SNPs (rs13192471, rs660895 and rs6457617) with susceptibility and severity of RA in an ethnically distinct North‐east Indian population. Whole blood was collected from clinically characterized RA cases (satisfying the American College of Rheumatology 1987 criteria) (n = 123) and community‐based age and sex‐matched healthy controls (n = 156) with informed consent. The HLA‐DRB1 SNP analysis was performed for all the RA and control cases using ARMS‐PCR using case and control genomic DNA as template. Statistical analysis was performed by SPSSv13.0 software. The HLA‐DRB1 rs660895 showed both wild (AA) and heterozygote (AG) genotype but the heterozygote allele was found to be associated with reduced risk of RA compared to controls [OR = 0.531, p = .024]. The difference in distribution of rs6457617 polymorphism between RA and control cases was comparable [OR = 0.525, p = .079]. Significantly higher distribution of variant rs13192471 genotype was observed in RA cases (69.92%) compared to controls (46.75%) (p < .001) and was associated with increased risk of susceptibility to RA [OR = 2.576, p < .001] compared to controls, as well as progression to severity in RA cases [OR = 2.404, p = .048]. Combinatorially also, the presence of rs13192471 variant genotype was associated with increased risk of RA susceptibility [OR = 8.267, p = .026] and RA severity [OR = 3.647, p = .280]. Alterations in HLA‐DRB1 are associated with RA susceptibility. HLA‐DRB1 rs13192471 SNP plays a critical role in RA susceptibility and severity in North‐east Indian cases and has prognostic significance in RA.