An infantile case of cytomegalovirus induced idiopathic thrombocytopenic purpura with predominant proliferation of CD10 positive lymphoblast in bone marrow.

An infant with cytomegalovirus infection (CMV) developed idiopathic thrombocytopenic purpura (ITP) at 4 months of age. A bone marrow (BM) aspiration showed a remarkable increase of immature megakaryocytes and prominent proliferation of lymphoblasts. Flow cytometric analysis of the bone marrow cells showed that the predominant cells in the lymphocyte cluster were of B-lineage (CD19) with CD10 (common acute lymphoblastic leukemia antigen) positive. Virus study showed a higher titer of CMV antibody. Cytomegalovirus DNA was detected by the polymerase chain reaction (PCR) method in urine, peripheral cells and marrow cells. Low-grade fever, diarrhea and petechiae were accompanied by mild liver dysfunction. Complete remission was made with intravenous high-dose immunoglobulin (IVIg) without progression to overt acute leukemia. The percentage of CD10+/CD19+ lymphocytes in bone marrow also diminished. We postulated that the proliferation of immature lymphocytes and megakaryocytes in bone marrow was caused by maturation arrest that might result from CMV infection.