ABNORMAL ERYTHROCYTE BAND 4.1 PROTEIN IN MYELODYSPLASTIC SYNDROME WITH ELLIPTOCYTOSIS

A case of myelodysplastic syndrome with haemolytic anaemia and a marke d elliptocytosis is reported. Sodium dodecyl sulphate-polyacrylamide g el electrophoresis (SDS PAGE) of erythrocyte membrane proteins reveale d that the patient's band 4.1 was decreased to about 50-70% of that of control and contained abnormal molecule migrating in a faster mobilit y than normal band 4.1, which was confirmed by immunoblotting. The act in/spectrin ratio of the patient's ghosts diminished to about 70% of t hat of control ghosts. Flow cytometric analysis showed that the glycop horin C content of the patient's erythrocytes was reduced but maintain ed the level of about 70% of that of normal. indicating that the glyco phorin C band 4.1 interaction might not be so seriously damaged as to cause elliptocytic shape change. We postulate that the abnormal band 4 .1 produced from the abnormal erythroid clone may be the primary molec ular defect and result in a dysregulation of spectrin-actin interactio n to cause erythrocyte shape change and membrane instability.