RELATIONSHIP BETWEEN ABO BLOOD-GROUP AND LEVELS OF GAL ALPHA,(3)GALACTOSE-REACTIVE HUMAN-IMMUNOGLOBULIN-G

Background. The terminal Gal alpha 1,3Galactose (alpha Gal) determinan t is present on all porcine glycoproteins and glycolipids, but is not expressed by human cells. Consequently human sera contain anti-alpha G al natural antibodies. The human blood group B antigen [Gal alpha 1,3( Fuc1,2)Galactose] is differentiated from the alpha Gal epitope by the presence of a fucosyl group. Methods. To determine whether the express ion of the B antigen has any effect on the level of alpha Gal-reactive natural antibodies, equal numbers (n = 12) of A, B, AB, and O serum s amples were evaluated by ELISA and flow cytometry. Results. A signific ant reduction in IgG alpha Gal reactivity was observed with serum samp les from B antigen-expressing donors (B, AB) relative to non-B antigen -expressing donors (A, O). Conclusions. These results are consistent w ith the possibility that anti-alpha Gal antibodies in non-B antigen-ex pressing individuals include a subset that is reactive with the struct urally related B antigen and that this subset is absent in B and AB in dividuals.