Studies on HLA antigens and cellular and humoral autoimmune phenomena in patients with myasthenia gravis.

The HLA phenotype of fifty-four patients with myasthenia gravis (MG) was compared to that of 600 controls. When male and female patients were compared separately with the control group, HLA-B12 was increased in MG males (P less than 0-023) and HLA-A1, B8 in MG females (P less than 0-023). In addition, HLA-A1, B8 was correlated with the early onset type of MG and with a more severe clinical course (Osserman scale IIb-III) in female patients. Cell-mediated immune responses were studied in a twenty-one hospitalized MG patients. Specific cell-mediated immunity to highly purified muscle proteins was investigated using the two-step-leucocyte migration agarose test and general cell-mediated immunity was studied by determining the cutaneous response to four extrinsic antigens. Cellular immune activity to muscle antigens occurred in fourteen out of twenty-one patients (67%) with MG and with one exception, in none of the controls. There was no significant difference in the LIF inducing ability of the different muscle antigens. A statistically significant correlation between HLA-A1 and B8 and either cell-mediated immune reactivity to muscle antigens or humoral autoimmune phenomena or clinical parameters was not found. Only a trend toward an association between HLA-A1 and B8 and a cell-mediated immune response to muscle antigens could be demonstrated. Positive delayed skin reactions to extrinsic antigens were observed with the same frequency as in healthy blood donors.