A case of acquired pure red cell anemia studied by cloning of erythroid progenitor cells in vitro.
A 70-year-old woman developed typical clinical symptoms of pure red cell anemia (PRCA) following a history of rheumatoid arthritis (RA). The patient's bone marrow erythropoietic progenitors cells were cloned in a micro agar culture system several times over a period of 11 months, revealing a diminished frequency of bone marrow erythroblasts paralleled by a markedly reduced number of CFU-e and BFU-e in vitro. No inhibitory activity in the patient's IgG fraction could be detected either by preincubation with IgG and/or rabbit complement, or in the continuous presence of IgG. Depletion of T lymphocytes from the patient's bone marrow cells led to an improved in vitro erythroid proliferation. Cytostatic therapy with cyclophosphamide clinically induced a marked increase in the bone marrow erythroblast and reticulocyte number, correlated in vitro by normalization of CFU-e levels and increase in the number of BFU-e. Nevertheless, BFU-e values never attained normal levels, which could be attributed to a reduced stem cell pool resulting from previous therapy with cyclophosphamide and/or antirheumatic drugs. Two independent factors, a reduced pool of committed stem cells as well as an autoimmune cell-mediated suppression, may both contribute to the pathomechanism of the disease in this patient.
D000368:Aged; D000741:Anemia, Aplastic / Q000097:blood* / Q000188:drug therapy; D001854:Bone Marrow Cells; D002999:Clone Cells / Q000166:cytology; D003114:Colony-Forming Units Assay; D003520:Cyclophosphamide / Q000008:administration & dosage; D004912:Erythrocytes / Q000166:cytology*; D004920:Erythropoiesis / Q000187:drug effects*; D004921:Erythropoietin / Q000502:physiology; D005260:Female; D006412:Hematopoietic Stem Cells / Q000166:cytology*; D006801:Humans; D007074:Immunoglobulin G / Q000502:physiology; D008212:Lymphocyte Depletion
D007074:Immunoglobulin G; D004921:Erythropoietin; D003520:Cyclophosphamide