Observations on the Racial Distribution of Variants of Blood Type rh′.

Abstract

Summary

Observations on a large series of blood donors indicate that the rare type rh′ is about 4 to 5 times as frequent among Negroids as among Caucasoids. Moreover, it is found that type rh′ bloods giving weak or “intermediate” reactions are about 5 to 6 times as common among Negroids as among Caucasoids, confirming previous observations on a shorter series of cases. It is pointed out that the existence of bloods giving weak reactions with anti-rh′ serum is more reasonably explained by postulating the existence of qualitative variants of the rh′ factor such as rh′^w, than by attributing the weak reactions to the presence of a smaller quantity of the factor rh′ in the blood. A similar explanation would apply to certain bloods giving “intermediate” reactions with sera anti-Rh_o, anti-rh’. anti-hr’, and anti-hr’.