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.