Isoimmunization in Pregnancy and the Varieties of Isoaǵǵlutinins Observed. ∗

The production of immune isoagglutinins following repeated transfusions, although of common occurrence in some animal species, is very rare in man. The first instance of this sort in man was described by Landsteiner, Levine, and Janes. 1

Levine and Stetson 2 described a case in which an intra-group ag-glutinin was responsible for severe post-transfusion symptoms, with anuria after the first transfusion. This occurred in a woman who, after retaining a dead fetus for a period of about 2 months, finally delivered a macerated fetus. In view of the activity of the agglutinin at 37° C and because of its gradual disappearance, it was believed that the antibody developed as a result of immunization, and it was suggested that the products of the retained dead fetus served as the antigenic stimulus. This suggestion seemed plausible because the cells of the husband, of the same blood group, (who was the donor) were sensitive to the action of the agglutinin. Presumably, the fetus inherited from the father a dominant agglutinogen which was absent in the tissues of the mother, who could thus be immunized.

Our own recent experience and other cases from the literature 3 indicate that the isoimmunization-hypothesis may hold also in certain cases of pregnancy with complications other than the retention of the dead fetus. In each of the cases cited, atypical agglutinins could be demonstrated in the absence of a history of repeated blood transfusions.

In 5 cases 4 there was a history of varying degrees of toxic symptoms during the pregnancy (in 2 of which macerated fetuses were delivered). In one of these cases, the patient had some fever, and rupture of the membranes occurred a few days before delivery, which was normal but followed by a post-partum endometritis. In 3 patients 5 the agglutinins were observed following abortion, one of them of the septic variety. One patient, whose eighth pregnancy resulted in premature separation of the placenta, had stillbirths in the 4 preceding pregnancies. 6 In 2 of the remaining 3 cases there were histories of repeated miscarriages but the present pregnancies, apparently normal, had to be terminated by Caesarian section.† In one case the pregnancy was normal except for morning vomiting during the last six weeks; due to lack of progress in labor the delivery was by Caesarian section. 7