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

Abstract

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.