ABSTRACT

Human parvovirus B19 (HPV-B19) infection is the etiological agent for the common childhood disease erythema infectiosum (‘‘fifth disease’’) in healthy children, which usually appears as a mild, febrile illness or subclinical infection. Although most individuals with human HPV-B19 infection are asymptomatic, several clinical conditions have been linked to this virus. The infection can also cause transient arthralgias in adults and hydrops fetalis after maternal infection during pregnancy, as well as intrauterine fetal death. Some of the hematologic manifestations of HPV-B19 infection are aplastic crisis in patients with chronic hemolytic anemia and chronic pure red cell aplasia in immunocompromised patients. The frequency and clinical importance of HPV-B19 infection has been investigated in various malignancies and cytopenias. HPV-B19 causes a lytic infection of erythroid progenitor cells in the bone marrow, leading to a suppression of erythropoiesis. Following HPV-B19 infection, immunocompetent individuals usually develop reticulocytopenia with a slight clinical drop in hemoglobin concentration, whereas individuals suffering from hemolytic disorders may develop a severe, even life-threatening red-cell aplasia due to their rapid erythrocyte turnover. Furthermore, immunosuppressed individuals may develop a persistent B19 infection with chronic anemia. In persistent HPV-B19 infections, there is generally a decrease or absence of erythroid precursors. Studies of HPV-B19-infected children with hematological malignancies have shown that they usually present with persistent anemia and not the immunemediated symptoms of rash or arthropathy. They also showed that megakaryoblasts and lymphoblasts could be affected and that some patients were even pancytopenic. Here, we report a 5-month-old girl presented with severe iron deficiency anemia, later diagnosed as having leukemia. Initial physical examination revealed palor and hepatosplenomegaly. Laboratory evaluation showed hemoglobin: 5.5 g/dL (MCV: 73 fL), leukocyte: 12.200/mm³; platelet: 266.800/mm³ and reticulocyte: %0.9. Serum iron decreased, iron binding capacity increased and ferritin was low. Peripheral smear showed hypochromia and microcytosis with monocytosis. Routine biochemistry and electrolytes were normal. During evaluation of her persisting anemia and hepatosplenomegaly, serum anti-HPV-B19 IgM was found to be positive, later it became negative and specific IgG titration increased. On the 27th day of admission; while hemoglobin and platelet were continuing low even after transfusions, leukocytes increased up to 160.000/mm³. Subsequent bone marrow aspiration revealed acute Myelomonocytic leukemia. Because of this patient, we want to discuss the controversial role of infections and specifically HPV-B19 in leukemias. A future possible vaccine might be utilized to prevent HPV-B19 infection in certain risk groups, such as the one presented in this case report. It is not definitely known whether HPV-B19 is one of the triggering factors or mimicking agents for leukemias. (JAREM 2013; 3: 119-22)

Keywords: Leukemia, human parvovirus-B19, aplastic crisis, erythema infectiosum, anemia