Association of HLA-B8, DRw3, and anti-acetylcholine receptor antibodies in myasthenia gravis.

Twenty-eight patients with myasthenia gravis (MG), five with and 23 without thymoma, and 47 normal controls were typed for serologically defined HLA-A, B, C, and DRw antigens. Sera from all patients were titered for antibodies to acetylcholine receptors (AChR). The frequency of HLA-B8 and DRw3 in the non-thymoma MG patients was significantly higher than in the normal population. Most of the non-thymoma patients with AChR titers higher than the average level were positive for HLA-B8 and/or DRw3, while the majority of the HLA-B8(-) and/or DRw3(-) non-thymoma patients demonstrated AChR titers below average. These findings support the possibility of the existence of immune response genes in the HLA-B, DRw segment of the major histocompatibility complex which are concerned in the response to or recognition of autoantigens.