Parvovirus B19 infection-associated red-cell aplasia in renal-transplant recipients: clues from the bone marrow

Parvovirus (PV) B19 is recognized as a rare cause of red-cell aplasia (RCA) in transplant recipients. In a report by Geetha et al. (1), it was shown that only 26 cases of PV B19-induced RCA had been documented in solid-organ transplant recipients. At a center in Italy, the rate of active PV B19 infection in transplant subjects was as low as 1.42% (2). The virus affects the early progenitor cells, resulting in the pathognomic morphology of giant proerythroblasts (GPE), with absence of intermediate and late normoblasts from the bone marrow. Here, we report a case of a living-related renal-transplant recipient in which the bone marrow revealed the typical morphology of RCA caused by PV B19 infection. Case Report A 45-year-old male received a living-related renal allograft for end-stage renal disease. Immunosuppression in the first 2 months after the renal transplant was with cyclosporine, azathioprine, and prednisolone, and thereafter it was changed to mycophenolate, tacrolimus, and prednisolone. Six months later, the patient developed symptoms related to anemia (hemoglobin 5.1 gm/dL). Blood transfusions, folate, and vitamin B12 supplements and, later, a trial of erythropoietin failed to raise the hemoglobin levels. Nine months after the renal transplant, his hemoglobin had dropped to 2.6 gm/dL, with a reticulocyte count of less than 0.2%. The white-cell and platelet counts were normal. He was transfused with 3 units of blood. A bone marrow performed revealed a normocellular marrow with marked erythroid hypoplasia. Striking GPE with prominent intranuclear inclusions and cytoplasmic vacuolations (Figure 1) suggestive of PV B19 infection were present. Mycophenolate and tacrolimus were discontinued, and cyclosporine A and azathioprine were restarted. After intravenous immunoglobulins (400 mg/kg per day) were given for 5 days, his hemoglobin rose to 13 g/dL within 1 month. He remains transfusion free to date. Figure 1: Giant pronormoblasts with prominent intranuclear inclusions and cytoplasmic vacuolations. (May Grunwald Giemsa).Discussion The postrenal transplant state on immunosuppression therapy is now recognized as one of the settings for PV B19-induced RCA (3). Tacrolimus and mycophenolate therapy has been associated with this infection. It is important to recognize this infection in renal and other organ-transplant patients, not only because is it treatable but also to prevent nosocomial transmission to other patients (4). The usual diagnostic modalities used in the West include serology (indicative of past or recent infection) and DNA studies to assess viral load and active infection. In this case, the bone marrow showed characteristic cytomorphologic features of PV B19 infection. There was an excellent response to immunoglobulins. PV B19 infection-associated RCA, in certain susceptible groups, is probably not that well recognized in developing countries such as India either because of lack of suspicion or nonavailability of specific DNA-based tests. Although it is invasive and painful, the bone-marrow examination may be a useful tool in the diagnosis of this infection in posttransplant patients with anemia that is unresponsive to vitamin supplementation and erythropoietin. Gurjeewan Garewal Jasmina Ahluwalia Neelam Varma Reena Das Vinay K. Sakhuja