Expression of c-myc, c-Ki-ras and c-Ha-ras oncogene products in peripheral blood mononuclear cells from patients with myasthenia gravis.

The oncogene products of c-myc, c-Ki-ras and c-Ha-ras and the subsets of natural killer cells in the peripheral blood mononuclear cells (PBMC) from 39 patients with myasthenia gravis (MG) and 40 healthy individuals were studied by immunocytochemical procedures. The MG patients showed an increased expression of c-myc, c-Ki-ras and c-Ha-ras oncoproteins in both lymphocytes and monocytes compared to those of healthy individuals (P < 0.01, P < 0.005 and P < 0.001, respectively). On the contrary, the number of Leu-7-Leu-11c+ cells of MG patients was less than that of healthy controls (P < 0.05). The oncogene expressions in PBMC of MG patients correlated positively with white blood cell counts, total natural killer cell counts (NK), Leu-7+Leu-11c+ of NK cell subset, gamma-globulin, erythrocyte sedimentation rate and serum immunoglobulins; the oncogene expressions were negatively correlated with the Leu-7+Leu-11c-NK subset. Thus, the increased expressions of c-myc, c-Ki-ras and c-Ha-ras oncoproteins accompanying the decreased Leu-7-Leu-11c+NK cell in MG PBMC are likely responsible for the acceleration of the clinical manifestations in MG patients.