Landsteiner's discovery of the genetically determined ABO blood group system had an enormous impact on clinical medicine. In addition to paving the way for safer transfusions, it led to subsequent discoveries of many other blood group systems, particularly the clinically important Rh group and its role in hemolytic disease of the newborn. And currently the ABO system identification plays an important role in assessing host-donor compatibility for organ transplantation.
Discovered by an immunologist and extensively studied by population geneticists, epidemiologists, biochemists, and serologists, the ABO group system affects many disciplines besides, clinical medicine, and it links them, often in an unexpected manner. One such link is the relationship of certain diseases to a particular ABO type. During the past two decades this relationship has been particularly stressed in numerous reports on the association between duodenal ulceration and group O individuals. Results obtained from ten centers1 have shown that the