Pure red cell aplasia: lymphocyte inhibition of erythropoiesis.
The pathogenesis of pure red cell aplasia (PRCA) was studied in a patient who had no evidence of malignancy. In marrow culture, no erythroid colonies (from late erythroid progenitors [CFU-E]) but normal numbers of well-haemoglobinized erythroid bursts (from early erythroid progenitors [BFU-E]) were found, indicating that BFU-E existed in the patient but that their subsequent in vivo differentiation was inhibited. Autologous coculture studies suggested that inhibition was mediated by the patient's ER + lymphocytes. After remission was induced with cyclophosphamide, autologous ER + cells no longer suppressed in vitro erythropoiesis. However, cryopreserved ER + cells, obtained with anaemia, suppressed BFU-E growth from remission marrow. An expanded population of large granular lymphocytes (LGL) with ER +, Fc gamma +, T3+, T8+, HNK-1+, Ia-, M1 -- phenotype and no functional natural killer (NK) cell activity was noted during PRCA that reverted to normal with remission. For this patient, both in vivo and in vitro evidence demonstrates a cellular inhibition of erythropoiesis at the level of differentiation between BFU-E and CFU-E.
D001853:Bone Marrow / Q000473:pathology; D002478:Cells, Cultured; D003114:Colony-Forming Units Assay; D003520:Cyclophosphamide / Q000627:therapeutic use; D004912:Erythrocytes / Q000473:pathology; D004920:Erythropoiesis; D005260:Female; D005615:Freezing; D006801:Humans; D008214:Lymphocytes / Q000276:immunology* / Q000473:pathology; D008875:Middle Aged; D012010:Red-Cell Aplasia, Pure / Q000097:blood* / Q000188:drug therapy
D003520:Cyclophosphamide