A Case of Childhood Anemia Complicated by a Red Cell Membrane Sugar Chain Anomaly with Low Levels of Sialic Acid.

An 8-year-old girl presented with the pallor and purpura. She was diagnosed to suffer from anemia of an unknown cause with leukocytopenia and thrombocytopenia. The patient's red cells showed marked agglutination with peanut lectin (PNA), and erythroblasts forming CFU-E in the bone marrow reacted positively to avidin labeled PNA on enzyme immunohistochemistry, suggesting an abnormality of sugar chain on red cell and also erythroblast membranes. Membrane O-glycan sugar chains of her red cells showed a low level of sialic acid on high performance liquid chromatography (HPLC). Her anemia failed to respond to the corticosteroids, γ-globulin, recombinant erythropoietin (rhEPO), and recombinant granulocyte colony stimulating factor (G-CSF), and frequent red cell transfusion was required. After 6 years, the patient underwent an unrelated bone marrow transplantation (U-BMT). From 2 weeks after transplantation, the PNA reactivity of her red cells decreased and then disappeared and the red cell membrane antigens changed to the donor type after 4 weeks. These results suggested that the sugar chain abnormality causing low levels of sialic acid in the red cell membrane was already present on erythroid progenitor cells in the bone marrow.