8. Pure Red Cell Aplasia
Pure red cell aplasia (PRCA) is characterized by normocytic anemia, reticulocytopenia, and absence of mature marrow erythroid progenitors. PRCA is distinguished from aplastic anemia by relatively normal leukocyte and platelet counts. It can be congenital or acquired. Acquired PRCA can be idiopathic or secondary, either an acute, self-limiting disorder or a persistent, chronic refractory anemia. PRCA can arise in association with a thymoma, lymphoid cancer, parvovirus, rheumatoid arthritis, pregnancy, and drugs.
PRCA can be acquired through exposure to a number of drugs, including immunosuppressants (azathioprine, FK506, antithymocyte globulin), antibacterials (linezolide, isoniazid, rifampin, chloramphenicol), antivirals (interferon-alpha, lamivudine, zidovudine), fludarabine, anticonvulsants (diphenyldrantoin, carbamazepine, valporic acid), as well as chloroquine, allopurinol, ribavirin, and gold [28, 29].
Additionally, PRCA has been reported to develop after prolonged exposure to recombinant human erythropoietin (rHuEPO) specifically the brand Eprex, predominately used in Europe [30–33]. Withdrawal of rHuEPO followed by treatment with immunosuppressives (cyclosporine A) for several months rendered patients anti-EPO antibody negative and transfusion independent. PRCA seemed to occur predominantly with subcutaneous administration in renal failure patients. The frequency of this complication has reduced, seemingly as a result of changes in formulation and handling that may have decreased immunogenicity [33].