Surface phenotypes of lymphoid cells altered in the human myasthenic thymus.

We investigated surface phenotypes of peripheral blood lymphocytes and thymic lymphoid cells from patients with myasthenia gravis (MG) by fluorocytometry, using monoclonal antibodies to human lymphoid cells. There were no significant differences in peripheral blood lymphocyte subsets in myasthenic patients, with or without a thymus. In the MG hyperplastic thymuses, the percentage of OKIa1+ cells or CCB1+ cells was significantly increased compared with controls. Although there were no significant differences in the percentage of T-cell lineage (CD3+, CD4+, CD8+, or CD1+ cells) between MG hyperplastic thymuses and the controls, the surface densities of T-cell lineage antigens (CD3, CD4, and CD8) were significantly increased on lymphoid cells in MG hyperplastic thymuses, compared with those in control thymuses. There were no significant differences in the percentage or fluorocytograph of lymphoid cells between the MG thymomas and the controls.