ASSOCIATION OF HLA‐DRw9 WITH MYASTHENIA GRAVIS IN CHINESE

SUMMARYHLA phenotypes were studied in 59 Chinese myasthenia gravis (MG) patients. Unfractionated peripheral blood mononuclear cells were used for typing of HLA‐A, B and C, and B‐enriched lymphocytes for HLA‐DR. Seventy‐nine healthy subjects were included as controls. When compared with healthy controls, the patients showed significant increases in HLA‐Bw46 (47·5% versus 14%, χ2= 18·7, P < 0·001), HLA‐DRw9 (59·3% versus 11%, χ2= 35·7, P < 0.001), while HLA‐DR3 was decreased (3·4% versus 32·9%, χ2= 18·2, P < 0.001). Further analysis showed that the primary association was with DRw9 and the increase in Bw46 was secondary to it. Both HLA‐Bw46 and ‐DRw9 were increased in all subgroups except where the age of onset was greater than 40 years. Finally, the HLA‐A2‐Bw46‐DRw9 combination was also significantly increased in patients (25.4% versus 5.1%, χ2= 11.5, P < 0.001), especially in the subgroups of MG with age of onset of less than 10 and males with age of onset of less than 40 years.