Pure red cell aplasia--evidence for an inhibitory action of the bone marrow adherent cell layer.

Evidence is presented for an inhibitory action of the bone marrow adherent cell layer on erythropoiesis in a case of pure red cell aplasia. Cultures of the patient's bone marrow with autologous and normal plasma showed normal numbers of CFU-C, but total absence of BFU-E. There was no inhibition of BFU-E when normal bone marrow was cultured with the patient's plasma. T-cell depletion of the patient's bone marrow did not affect these results, but after removal of the adherent cells, normal numbers of BFU-E were cultured. These observations suggest that the adherent cells, which are predominantly macrophages, were responsible for the inhibitory action on erythropoiesis.