Acquired pure red cell aplasia

Pure red cell aplasia is a rare disorder characterized by the presence of a severe anaemia which is normochromic and normocytic. The symptoms are those of anaemia, and apart from pallor there are no abnormal physical signs in the untreated patient. The bone marrow shows a virtual absence of red cell precursors, but production of granulocytes and platelets is normal. Occasionally in the later stages a pancytopenia or haemolytic state may supervene. The two main forms are the congenital type described by L. K. Diamond and K. D. Blackfan,1 which is of insidious onset in the first few months of life, generally has a poor prognosis, but occasionally undergoes spontaneous remission in puberty; and the acquired type seen in adults. J. R. Schmid and colleagues2 in a small series noted two peaks of incidence-the first in the early twenties, the second at ages 50 to 70. About a third of the patients with the acquired type have an associated thymoma. Fairly commonly there is a history of drug ingestion, particularly chloramphenicol,' less often of sulphonamides.2 Exposure to benzene has also been reported in some cases. A pure red cell aplasia produced by diphenylhydantoin,4 with rapid recovery on withdrawal of the drug, has been noted. The disease has also occurred in association with carcinoma of the bronchus and hypogammaglobulinaemia, and it has preceded the development of acute leukaemia. In the case of thymoma and possibly some drugs a close aetiological connexion must be admitted. Though there is a close association of pure red cell aplasia with thymic tumour the results of thymectomy are not coniistent.' 6 Treatment with cortisone, corticotrophin, and testosterone has been reported to correct the anaemia in the idiopathic acquired type of disease. Three cases reported by H. E. Finkel and his colleagues5 are remarkable in that they dll responded to cortisone or prednisolone on as many as four occasions. The authors suggest that these patients either had v dependence on a pharmacological dose of corticosteroid or possibly owed their improvement to the suppression of an _utoimmune mechanism. It is known that erythropoiesis is mnder the control of the glycoprotein erythropoietin. J. C. Schooley and J. F. Garcia' have shown that it is possible toi produce an antibody to this protein and have induced anaemia in mice by means of the antibody. Though evidence for such a mechanism in man is slight, A. S. Gordon8 recounts the case of a boy with pure red cell aplasia who had no erythropoietin in his plasma when he was anaemic, whereas during recovery his urine and plasma contained erythropoietin. Another possibility is that an inhibitor of haemoglobin synthesis is present.9 In the absence of any definite idea of the cause of the adult acquired form of this disease, treatment remains empirical. At present a trial of corticosterone either alone or in combination with testosterone or oxymethalone is suggested as the first approach. If this regimen fails, the need for splenectomy and thymectomy should be considered.