Abstract
During childhood, anemia includes a group of anemia of unknown etiology, although the contribution of congenital and familial factors is strongly suspected. This group includes Diamond-Blackfan anemia (DBA), Fanconi's anemia (FA) and amegakaryocytic thrombocytopenia (AMT), which are included in the conventionalclassification, and as to hypoplastic anemia, so called ill-defined dyshematopoiesis (IDD), which is the transient type. The author pathophysiologically analyzed these types of childhood anemia with respect to red cell membrane components, such as protein, lipid and sugar. The peanut lectin (PNA) agglutination test showed a persistent positive agglutinated reaction to PNA not only in peripheral red cells but also in the bone marrow erythroblasts of the anemic children as well as some of the cord-blood cells, but was not observed in other anemic children. This abnormality may have contributed to red cell-membrane sugar chain anomalies. When analyzed by HPLC, the sugar chains derived from erythrocyte membrane showed the O-linked sugar-chain (O-glycan) peak wave pattern as observed with red cells treated with sialic acid-cleaving enzyme (vibrio cholerae : VC), making them test positive for PNA agglutination. These sugar chain anomalies showed similar properties to the immature chain of cord-blood red cells or to the loss of sialic acid from O-glycan in VC-treated red cells in which an incomplete sugar chain of sialic acid was lost. Therefore, the abnormal sugar chain expressed on red cell membranes may have induced anemia in these patients. DBA may have membrane sugar chain-forming anomaly at the level of CFU-E. If such anomaly also occurs at the levels of CFU-GM and CFU-Meg, FA, AMT or IDD may develop. The results of this study suggest that hypoplastic anemia with sugar chain anomaly (HASA) may be established as a group of anemia.
