Lymphocytes suppressing both immunoglobulin production and erythroid differentiation in hypogammaglobulinaemia

CELLS blocking immunoglobulin (Ig) synthesis in vitro have been found among gradient-isolated blood mononuclear cells of individuals with variable immunodeficiency 1–4 , immunodeficiency with thymona 1,3,4 , infantile X-linked immunodeficiency 4 , multiple myeloma 5 and Hodgkin's disease 6 . It has been suggested that the suppressor cells block terminal differentiation of human B lymphocytes 7 . The association of red cell aplasia and immunodeficiency states is well documented 8 . A circulating Ig capable of interfering with red cell formation has been demonstrated in several persons 9,10 . The majority of individuals with these disorders, however, have no circulating inhibitor of erythro-poiesis. In the present study, lymphocytes from two persons with immunodeficiency with thymoma, one of whom had repeated episodes of red cell agenesis, were cocultivated in assay systems in which human blood B lymphocytes and human bone marrow erythroid precursors differentiate in vitro . The results suggest that the ‘suppressor’ cells observed in certain immunodeficiency diseases may act on both lymphocytic and haematopoietic target cells.