HLA phenotypes and
autoantibody responses were studied in 71 Japanese patients with
myasthenia gravis.
HLA-A2, Bw61, and DRw9 were associated with
ocular myasthenia gravis (corrected p [CP] less than 0.05 relative risk [RR] = 2.88; CP less than 0.02, RR = 3.60; and CP less than 0.001, RR = 4.63, respectively) and
HLA-DRw8 was associated with
generalized myasthenia gravis (CP less than 0.001, RR = 5.40). Neither
HLA-B8 nor DR3 was found in Japanese patients. The titer of antiacetylcholine receptor antibody (AChR Ab) and the incidence of
autoantibodies other than AChR Ab were higher in patients with
generalized myasthenia gravis than in those with the ocular type (2.77 +/- 0.62 versus 0.17 +/- 0.03 pmol/ml, p less than 0.001; and 60.6 versus 29.0%, p less than 0.02, respectively). Patients with a high titer of AChR Ab or with
autoantibodies had an increased frequency of
HLA-DRw8 (CP less than 0.02, RR = 4.61, and CP less than 0.005, RR = 4.53, respectively); whereas patients with a low titer of AChR Ab or without
autoantibodies had an increased frequency of
HLA-DRw9 (CP less than 0.001, RR = 8.26, and CP less than 0.005, RR = 4.08, respectively). These findings suggest that ocular and
generalized myasthenia gravis might have different immunogenetic backgrounds.