Genetic association of HLA‐DRB1 multiple polymorphisms with dermatomyositis in Chinese population

Genetic variation in HLA plays an important role in the pathogenesis of dermatomyositis (DM). The aim of this study was to investigate the association of HLA class II with DM in China. Two hundred and twenty‐four DM patients and 300 healthy controls were randomly enrolled at China‐Japan Friendship Hospital. High‐resolution typing of HLA‐DRB1 alleles was performed by sequencing based typing. The HLA‐DQA1 and HLA‐DQB1 alleles were determined by polymerase chain reaction sequence‐specific primers. The frequencies of HLA‐DRB1*09:01 (28.6% vs 11.3%, P < .0001, odds ratio, OR = 3.14, 95% confidence interval, CI = 2.47‐3.99) and HLA‐DRB1*12:01 (29.0% vs 11.0%, P < .0001, OR = 3.30, 95% CI = 2.59‐4.20) in DM patients were significantly higher than that in healthy controls. No significant difference was found in HLA‐DQA1 or DQB1 alleles between DM patients and healthy controls. Furthermore, DM patients with anti‐melanoma differentiation‐associated gene 5 antibody (anti‐MDA5) had a significantly higher frequency of HLA‐DRB1*12:01 compared to that for patients without anti‐MDA5 (P < .0001, OR = 4.77, 95% CI: 2.29‐9.93). Multivariate binary logistic regression analysis was performed to identify the risk factors for interstitial lung disease. The HLA‐DRB1*09:01 allele was a poor prognostic factor (P = .01, OR = 9.21, 95% CI: 1.47‐57.50) for DM patients with anti‐MDA5 autoantibody. In summary, our findings indicate that HLA‐DRB1*09:01 and HLA‐DRB1*12:01 alleles may contribute to susceptibility of adult DM in Han Chinese population. In addition, the DRB1*12:01 genotype is significantly associated with the presence of anti‐MDA5 antibody in DM patients.