Immunologic response in vitro after thymechtomy in patients with myasthenia gravis.

Thymectomy in adult animals impairs immune functions such as lymphocyte response to phytohemagglutinin (PHA) and to allogeneic cells. The responses of lymphocytes from 18 myasthenia gravis patients, 12 of whom had undergone thymectomy, were studied; the interval between thymectomy and investigation ranged from 1 month to 26 years (mean, 9.5 years). Peripheral blood lymphocytes were cultured in autochthonous plasma or homologous AB serum. In vitro responses to stimulation with PHA, concanavalin A and allogeneic monomuclear cells were within the 95% range of normal responses in all patients. Because our findings contrast with the definite immune defects resulting from thymectomy found in adult animals, longer follow-up is needed.