Studies on lymphocyte subpopulations and their responses to mitogenic stimulations of myasthenic patients.

The lymphocyte subpopulations, T and B-lymphocytes, and their re sponses to mitogenic stimulations in the peripheral blood, the bone marrow, and the thvmus were analvsed in the patients with mvasthenia vravis. The lymphocytes were isolated on 'Ficoll-Conray 400' gradient. The T lymphocytes were identified by the sheep red blood cell-rosette-formation, and the B-lymphocytes by the surface immunoglobulin. The responses of lym phocytes to PHA-P and PWM stimulations were also studied in vitro using 3H-thymidine as indicator with the same lymphocyte lots in part of these samples. The mean value of the circulating T-lymphocytes among 11 healthy subjects tested was 1503•}342/cmm(M•}SD), whereas B-lymphocytes was 584•}133/cmm. Decreased T-lymphocyte and 13-lymphocyte with lower responsiveness to mitogens, especially to PHA-P, were characteristic in myasthenia gravis indi cating the abnormality of T-cell function. The extirpation of the thymus, either thymoma and/or non-thymomatous thymus with "B-cell origin lym phfollicle", induced the normalization of these lymphocytes dysfunction. The administration of immunosuppressants affected on the lymphocytes as same effect of thymectomy. Including the lymphocytes of the patients with systemic lupus erythematosus, these lymphocytes deficiency was in proportion to the severity of clinical symptoms. Local T and B-lymphocyte identification using E and EAC on the cryosections indicated that a major portion of lymphor rhage in the skeletal muscle of myasthenic patients was B-lymphocytes. The pathognomonic significancy of cellular immune deficiency and anti-membrane antibody was discussed.