The thymus in myasthenia gravis. Evidence for altered cell populations.

Abstract

Abstract Comparisons of several types of immunologic reactivity were made in thymic cells from six patients with myasthenia gravis and thymic hyperplasia, four patients with myasthenia gravis and thymoma and six age-matched control cardiac-surgery patients. In mixed leukocyte reactions, thymic cells from the subjects with hyperplasia were capable of stimulating autologous peripheral blood lymphocytes. Such reactivity was not seen in thymocyte-blood lymphocyte mixtures from the other two groups. There was an increased number of B cells in the thymic-cell populations from the myasthenic patients as compared to that in the control group, carrying predominantly IgM receptors. The thymic cells from myasthenic patients also responded more vigorously to pokeweed mitogen. These findings suggest altered populations of lymphoid cells in the thymus of myasthenic patients that react with autologous lymphocytes from other cell compartments. The pathogenic implications of these findings remain to be determined. (N Engl...