ABO(H) blood group antigens are typical carbohydrate antigens widely expressed on erythrocytes, digestive tissue, respiratory tissue, and in secreted body fluids such as milk, urine, and saliva. These antigens are mostly distributed as glycolipids or glycoproteins (1,2) Recently, human plasma von Willebrand factor (vWF) (3,4), coagulation factor VIII (FVIII) (5), and a portion of α2-macroglobulin (α2M) (6) have been found to possess covalently associated ABO(H) blood group antigens. There is no information about the physiological significance of the blood group antigens on these plasma glycoproteins, but some interesting relationship between concentration of vWF and blood groups has ben reported (7,8). Moreover, a number of blood group-related antigens have been found as clinical markers for carcinogenesis (9).