Autoreactive erythroid progenitor-T suppressor cells in the pure red cell aplasia associated with thymoma and panhypogammaglobulinemia.

In vitro erythroid culture studies and lymphocyte markers were performed in a patient with a spindle cell thymoma who developed red cell aplasia, panhypogammaglobulinemia, and multiple opportunistic infections. At the time of presentation, erythroid progenitor cells (CFUe, BFUe) were markedly reduced when cultured from marrow mononuclear cells. Removal of T cells from bone marrow mononuclear cells by E-rosetting or complement-mediated lysis with OKT3 pan T cell monoclonal antibody increased growth of erythroid progenitor cells in vitro. Readdition of bone marrow or pleural fluid T cells derived from the thymoma suppressed autologous, but not allogenic, erythroid progenitor cell (CFUe, BFUe) proliferation in vitro. The erythroid progenitor suppressor T cells were predominantly OKT11+, OKT3+, OKT8+ and Ia+ consistent with activated suppressor T cells. Treatment of the patient with cyclophosphamide and corticosteroids reduced marrow lymphocytes fourfold, and a prompt reticulocytosis ensued. After recovery, erythroid progenitor cells were easily detectable. These studies provide new evidence for T cell-mediated suppression of erythropoiesis in a unique subset of patients with red cell aplasia associated with thymoma and hypogammaglobulinemia.