title: T gamma (T gamma) cells suppress growth of erythroid colony-forming units in vitro in the pure red cell aplasia of B-cell chronic lymphocytic leukemia.
abstract: In vitro studies were performed in two patients with B-cell chronic lymphocytic leukemia who developed pure red cell aplasia (CLL-PRCA). During the active phase of their red cell aplasia, there was a marked reduction in the numbers of erythroid colony-forming units (CFU-E). Unfractionated sera or separated IgG fractions from these patients did not impair CFU-E proliferation from either autologous or allogeneic marrows. Increased numbers of T lymphocytes were present in marrow aspirates of these patients. Analysis of these T cells indicated that 90 and 35%, respectively, bore Fc receptors for IgG (T gamma cells). Removal of T cells by E-rosetting techniques augmented CFU-E growth in CLL-PRCA 10-fold. Similar treatment of normal marrows did not cause similar enhanced growth of CFU-E. Co-cultures of marrow T cells or T gamma cells obtained during the active phase of CLL-PRCA suppressed CFU-E growth from autologous or allogeneic marrows. After achieving drug-induced remission of the PRCA, marrow T cells were no longer inhibitory. In contrast, BFU-E (erythroid burst-forming units) or granulocyte proliferation in diffusion chambers were not suppressed by CLL-PRCA T cells. These findings suggest that the development of PRCA in B-cell CLL may result from suppression of CFU-E proliferation by T gamma cells.
mesh_terms: D000741:Anemia, Aplastic / Q000503:physiopathology; D001402:B-Lymphocytes / Q000145:classification; D001853:Bone Marrow / Q000503:physiopathology; D002478:Cells, Cultured; D003114:Colony-Forming Units Assay; D004920:Erythropoiesis; D006801:Humans; D007142:Immunoglobulin gamma-Chains / Q000276:immunology; D007945:Leukemia, Lymphoid / Q000145:classification / Q000503:physiopathology*; D011948:Receptors, Antigen, T-Cell / Q000276:immunology; D013601:T-Lymphocytes / Q000145:classification / Q000502:physiology*
chemical_list: D007142:Immunoglobulin gamma-Chains; D011948:Receptors, Antigen, T-Cell