[Actual problems of the H blood group immunogenetics (author's transl)]

The quantity of H blood group antigen produced by the H gene product, 2-alpha-fucosyltransferase, has a key importance in the A, B and Leb antigen formation. The H blood group deficiency results always in a more or less expressed insufficiency fo the A, B and Leb antigen production. More thorough investigations of the "Bombay" and "Para-Bombay" blood groups have shown, that an absolute lack of the H antigen on the red cells of this type probably does not exist at all. The production of H antigen is only in one or both chemical forms more of less suppressed. The formation of the H antigen is under control not only of the structural gene and of its mutants, but also of the action of at least two types of regulator genes, one of them controlling the formation of the glycoprotein, the other one the glycolipid form of the H antigen. Considerations about the probable genetic background of the recessively inherited Oh or OHx, Ah, Bh and OHz, as well as of the dominant Hm phenotypes, are presented. The heterogeneity and individuality of the ABH blood groups of the same specificity is pointed out.