1. Allelic variants, some of which lead to adverse transfusion reactions , are known. 2. In addition to the transmission of infection, certain types of transfusion reaction . 3. Anti-M although occurring naturally has rarely been implicated in transfusion reactions . 4. Anti-S and anti-s can cause hemolytic transfusion reactions and hemolytic disease of the newborn. 5. Anti-M and anti-N antibodies are usually IgM and are rarely associated with transfusion reactions . 6. Fewer transfusions mean fewer transfusion reactions , infections and so on. 7. Anti-Wr a can also cause severe hemolytic disease of the newborn and severe transfusion reaction . 8. Anti-U has been associated with both hemolytic transfusion reactions and hemolytic disease of the newborn. 9. This enables management and investigation of any suspected transfusion related disease transmission or transfusion reaction . 10. Antibodies to Vel have been implicated in transfusion reactions .