Thrombocytopenia induced by human parvovirus B19 infections

Human parvovirus B19 (B19) has a remarkable tissue-tropism for erythroid elements--from erythroid precursors (BFU-E, CFU-E) to erythroblasts. B19 is thought to be incapable of propagating in cells other than erythroid progenitors. Leukocytopenia and thrombocytopenia sometimes occur in addition to erythrocytopenia in patients with B19 infection. We retrospectively investigated the possible cause of thrombocytopenia by B19 infection in 23 patients with thrombocytopenia admitted to our hospital in the past 5 years. Two patients were found to be infected by B19. Mild thrombocytopenia in both cases was thought to be an early event in B19 infection.