Increased frequency of DRB1*11:01 in anti–hydroxymethylglutaryl‐coenzyme A reductase–associated autoimmune myopathy

OBJECTIVE: To investigate the association of anti-hydroxymethylglutaryl-coenzyme A reductase (anti-HMGCR) myopathy with HLA class I and II antigens. METHODS: HLA antigens were determined in 1) 20 white and 8 African American anti-HMGCR patients, 2) 487 white and 167 African American controls, and 3) 51 white subjects with mild self-limited statin intolerance. RESULTS: White anti-HMGCR patients had a higher frequency of the combination HLA-DR11, DQA5, and DQB7 than controls or statin-intolerant subjects (70% versus 17%; odds ratio OR 11.7 95% confidence interval (95% CI) 4.0-35.3, P = 4.1 × 10(-7) and 70% versus 21%; OR 8.3 95% CI 2.2-33.9, P = 5.4 × 10(-4) , respectively). This combination was not increased in African American anti-HMGCR subjects compared to controls (13% versus 3%; OR 4.6 95% CI 0.2-53.3, P = 0.2). However, DR11 was increased in African American anti-HMGCR patients compared to controls (88% versus 21%; OR 26.4 95% CI 3.1-590.3, P = 0.0002). High-resolution mapping showed that 95% with DR11 had DRB1*11:01. DQA1 and DQB6 were less frequent in white anti-HMGCR-positive patients compared to controls (25% versus 65%; OR 0.2 95% CI 0.1-0.5, P = 5.5 × 10(-4) and 0% versus 45%; OR 0.0 95% CI 0.0-0.3, P = 2.1 × 10(-5) , respectively). DRB11 was not associated with particular disease features. CONCLUSION: DRB1*11:01 is associated with an increased risk of anti-HMGCR myopathy in whites and African Americans. These findings suggest a mechanistic link between statin exposure, increased HMGCR expression, and the possible presentation of HMGCR-derived peptide(s) by DRB1*11:01.