[Hereditary spherocytosis first diagnosed upon the development of aplastic crisis; a case report].

We report a Childhood case of hereditary spherocytosis (HS) first diagnosed upon the development of aplastic crisis. A 6-year-old boy presented with fever and anemia. Although there was neither icterus nor splenomegaly at first, mild icterus and splenomegaly gradually developed with improvement of anemia. The diagnosis of HS was made on the basis of the presence of numerous spherocytes on the peripheral smear, increased osmotic fragility and the auto-hemolysis test result. The severe anemia in the early course with a marked decrease in the bone marrow erythroid cells and the absence of icterus and splenomegaly indicate that it was due to aplastic crisis. In the virological study, anti-human parvovirus (HPV) antibody titers were increased: the values of anti-HPV IgM were high and those of anti-HPV IgG were suddenly elevated. We thus considered that this HS case developed aplastic crisis by HPV infection.