HLA class II alleles may influence susceptibility to adult dermatomyositis and polymyositis in a Han Chinese population

BACKGROUND Polymyositis (PM) and dermatomyositis (DM) are idiopathic inflammatory myopathies. Genetic variability in human leukocyte antigen (HLA) genes plays an important role in the pathogenesis of PM and DM. However, few studies on the subject in Chinese populations have been reported thus far. METHODS We studied the influence of HLA polymorphisms on DM and PM susceptibility by analyzing HLA-DRB1, HLA-DQA1, and HLA-DQB1 alleles in 71 adult DM patients, 20 adult PM patients, and 113 controls in a Han Chinese population. RESULTS A positive association was found between HLA-DQA1*0104 and DM (p = 0.01; corrected p (pcorr) NS; odds ratio (OR) = 2.58; 95% confidence interval (CI): 1.18-5.64), while an inverse correlation was noted between HLA-DQB1*0303 and myositis patients with interstitial lung inflammation (p = 0.01; pcorr NS; OR = 0.25; 95% CI: 0.07-0.73). A positive relationship was also observed between HLA-DRB1*07 and DM (p = 0.01; pcorr NS; OR = 2.26; 95% CI: 1.12-4.59), while HLA-DRB1*03 seems to be protective against DM (p = 0.01; pcorr NS; OR = 0.26; 95% CI: 0.06-0.81). The lung complication was closely associated with HLA-DRB1*04 (p = 0.01; pcorr NS; OR = 2.82; 95% CI: 1.15-6.76) and HLA-DRB1*12 (p = 0.02; pcorr NS; OR = 2.52; 95% CI: 1.02-6.07). The frequency of HLA-DRB1*07 was significantly higher among myositis patients with dysphagia than among controls (p = 0.01; pcorr NS; OR = 4.78; 95% CI: 1.03-24.42). The putative haplotype DRB1*07-DQA1*01-DQB1*02 was positively correlated with DM (p = 0.03; pcorr NS; OR = 2.90; 95% CI: 1.02-8.93) and the lung complication (p = 0.02; pcorr NS; OR = 3.45; 95% CI: 1.04-11.58). CONCLUSIONS Our results demonstrate that HLA alleles may be involved in susceptibility to adult DM and PM in the Han Chinese population.