HLA-DRB1*14 and DQB1*05 are associated with Japanese anti-MuSK antibody-positive myasthenia gravis patients

Background: Myasthenia gravis (MG) is an autoimmune disorder presumed to be associated with genetic susceptibility. This study aims to determine whether HLA is associated with MG in Japanese patients. Methods: We included 58 MG patients with anti-acetylcholine receptor antibody (AChR + MG) and 14 MG patients with muscle-specific receptor tyrosine kinase (MuSK + MG) and determined HLA-A, B, DRB1 and -DQB1 alleles using polymerase chain reaction with sequence-specific oligonucleotide and primers. AChR + MG was classified into the three subgroups: early-onset MG (EOMG; n = 11), late-onset MG (LOMG; n = 20), and thymoma-associated MG (n = 27). Healthy volunteers (n = 100) served as controls. Results: A significant positive association was observed between MuSK + MG with the DRB1*14 [57.1%, MuSK + MG vs. 18.0%, healthy controls (HC); odds ratio (OR): 6.1] and DQB1*05 [78.6%, MuSK + MG vs. 30.0%, HC; odds ratio (OR): 8.5]. We found a negative association between LOMG and DQB1*04 [5.0%, LOMG vs. 37.0%, HC; OR: 0.09]. There was no association between other MG subgroups and HLA alleles. Conclusion: HLA-DRB1*14 and DQB1*05 were associated with MuSK + MG, therefore these alleles may play important roles in developing MuSK + MG across the races. (C) 2016 Elsevier B.V. All rights reserved.