The Correlation of the Bga Blood Group with the HL‐A7 Leucocyte Group: Demonstration of Antigenic Sites on Red Cells and Leucocytes

Summary. Antigenic sites of Bga specificity have been demonstrated on leucocytes as well as on red cells. The Bga group shows almost complete concordance with the histocompatibility group HL‐A7. Red cells show much less activity than leucocytes and did not absorb cytotoxic antibodies but leucocytes removed all haemagglutinating activity. RNAP reactions can be demonstrated by both haemagglutiuation and cytotoxic tests. In some instances multispecific cytotoxic antibodies may show a monospecific haemagglutinating component. Family studies showed that the HL‐A groups may influence the Bga reaction of the red cells.