HLA antigens and susceptibility to myasthenia gravis

HLA-A, -B, -C and -DR antigen frequencies determined in a group of 73 myasthenia gravis (MG) patients were compared with those of a control group of 205 subjects. The strongest positive association with MG was found antigens B8 and DR3 (relative risks 9.56 and 8.84 respectively). Analysis of our data indicates that both antigens, independently from their linkage disequilibrium, are involved in susceptibility to MG. No relationship between HLA antigens on thymic pathology was observed in our material. In male MG patients the association with DR3 was weaker than in female patients. The difference in DR3 frequency between male and female patients was statistically significant; no significant difference was found for antigen B8. It appears that DR3 contributes to development of MG only in females. In male patients aged more than 30 years at the onset of disease, MG was not associated with B8 or DR3. In contrast, in female patients aged more than 30 years at the onset of disease there was a strong association of B8 and DR3 with the disease.