Differences Between Anti‐H and Anti‐OI Red Cell Antibodies

Both anti-0 and anti-H reagents preferentially agglutinate human group 0 red cells. When this activity is inhibited by H substance (secretor saliva) the serum is said t o contain anti-H; conversely, if not inhibited the serum is said to be anti-0 [7]. The recognition of anti-0 as separate from anti-H sera is of considerable theoretical importance in the search for the determinants of blood group specificity. Also, we have commented on this difference as being of practical importance in blood transfusion [4]. There is evidence that anti-0 destroys group 0 red cells in vivo and anti-H does not. The I blood group system has bearing on specificity in the ABO system. GOLD has described parallels between anti-0, anti-A,, and anti-I [2]. We have examined the relationship between anti-H and anti-I and contrasted this with anti-0 by serologic and in vivo compatibility studies.