A double-label flow cytometric analysis of the simultaneous expression of OKT4 and Leu2a antigens on circulating T lymphocytes in myasthenia gravis.

A two-color immunofluorescence analysis of circulating abnormal T lymphocytes bearing both helper (T4) and suppressor/cytotoxic (Leu2a) T cell markers (double marker cells) was performed by means of the laser flow cytometry system. The double marker cell level was very low in 6 patients with multiple sclerosis and 12 normal controls studied. Fifteen of 31 patients with myasthenia gravis (MG) showed an elevation of double marker cells without an increase in T6-positive cells. The values were significantly higher in patients with thymoma or thymic hyperplasia than in those with a normal thymus. The double marker cell level was considered to reflect thymic abnormality in MG and to be helpful for determining the indication of thymectomy.