THE INFLUENCE OF THE IN(LU) GENE ON EXPRESSION OF CDW75 ANTIGENS ON HUMAN RED-BLOOD-CELLS

The influence of the In(Lu) gene on human red blood cell (RBC) expression of CDw75 antigens was examined. CDw75 antigens were increased in expression on Lu(a-b-) cells of the dominant inhibitor type in comparison with red cells from donors of other Lutheran (Lu) phenotypes. In contrast, CD44 epitopes detected with F10-44-2, A3D8 and BU52 monoclonal antibodies (mAb) were decreased in expression on Lu(a-b-) red cells. Among normal blood donors of the common phenotype Lu(a-b+) there was a wide range of expression of CDw75 antigens on red cells. The results show that CDw75 is a quantitative polymorphism of human red cells and, among antigens influenced by the In(Lu) gene, is unique in being up-regulated in expression.