Intragroup incompatibility with respect to the Hr blood factors as a cause of minor hemolytic transfusion reactions

Abstract

Listen

Translate article

Abstract The introduction of routine Rh testing along with blood grouping tests as a basis of the selection of donors for transfusions has served to eliminate the danger of serious hemolytic reactions. Simultaneously there has been a reduction in the frequency of posttransfusion chills, as a result of the perfection of methods of eliminating pyrogenic materials from blood transfusion apparatus. Thus at the author's institution the frequency of febrile reactions dropped from 7.9 per cent in 1936 to 2.9 per cent in 1939 and to only 1.2 per cent by 1947 The virtual elimination of pyrogenic reactions has served to make more prominent another class of hemolytic reactions, usually only of minor severity, occurring in Rh-positive patients becoming sensitized by repeated transfusions given over a long period of time. In a series of twenty-three Rh-positive patients having febrile reactions and at the same time showing evidence of posttransfusion hemolysis, as many as seventeen were Hr negative (fourteen Rh 1 Rh 1 and three type Rh 2 Rh 2 ), while among ten patients with febrile reactions but without evidence of hemolysis none were Hr negative. This indicates that Hr sensitization plays a predominant role as a cause of hemolytic reactions in Rh-positive patients. Hr antibodies were clearly demonstrable in the sera of only three (two anti-hr′ and one anti-hr″) of the seventeen presumably sensitized patients. This indicates that Hr sensitization, when it occurs at all, is usually mild in degree. This conforms with the usual mild course of reactions caused by Hr sensitization in that such reactions are usually so harmless that they are passed off as ordinary pyrogenic reactions. However, that such reactions may sometimes endanger the life of the patient is demonstrated by the fact that one of the three patients with demonstrable antibodies died. While routine pretransfusion Hr typing is still not practicable, one should at least investigate every febrile reaction for evidence of hemolysis. If hemolysis has occurred even though the patient is Rh positive, Hr tests should be done. and if the patient is found to be Hr negative, only Hr-negative blood of a compatible blood group should be used for future transfusions. If Rh-negative patients have reactions despite transfusions of type rh blood, one should search for other sensitizations, particularly against the M factor. Particularly difficult to solve will be instances of multiple sensitization, one of the most common examples of which, in the author's experience, is double sensitization to factors Rh and M. Eventually blood transfusion practice should include suitable precautions to avoid sensitization against the Hr factors as well as the Rh factors, particularly in the case of women, in order to avoid the birth of babies with erythroblastosis caused by Hr sensitization.