[Aplastic crisis due to human parvovirus B19 infection in glucose-6-phosphate dehydrogenase deficiency]

Human parvovirus B19 is known to cause aplastic crisis in patients with hemolytic anemias due to cytotoxic effect of the infection to erythroid progenitor cells. We report here the first case of aplastic crisis by B19 in a patient with glucose-6-phosphate dehydrogenase deficiency. A five-year-old boy was admitted to the hospital because of severe anemia, fever and jaundice. Four weeks after admission, he developed erythema infectiosum. B19 infection was confirmed using countercurrent immunoelectrophoresis, Southern blotting and hybridization method, and radioimmunoassay for B19 specific IgM. B19 virus antigen was detected by an indirect immunofluorescent method in both the cytoplasm and nucleus of large mononuclear cells that had no granules in bone marrow. On admission, the hemoglobin was 3.1 g/dl and no reticulocytes were detected in the peripheral blood smear. Bone marrow examination revealed a normocellular marrow with erythroid hypoplasia and M/E ratio of 7.38. Large basophilic erythroblasts containing vacuoles were also noticed. Elevation of indirect bilirubin and hemoglobinuria suggested intravascular hemolysis. Transient mild thrombocytopenia associated with increased PAIgG was observed. It is likely that B19 virus infection caused hemolysis which contributed to severe anemia.