The Risk of Immunization to IgG Following Rh Immune Globulin Therapy

Abstract

Three hundred thirteen women were typed for Gm and Inv factors and screened for the presence of antibodies to gamma globulin both before receiving Rh immune globulin and at six weeks, three, six, and nine months after injection. Thirty‐five of the 313 women received multiple doses of Rh immune globulin following one or more pregnancies. In this group of patients, the incidence of anti‐gamma globulins was no greater than in the women given a single 0.7 to 2.25 ml dose. Anti‐gamma globulins were found in only 17 women (5.4%). Eleven had antibody prior to treatment and in six it first appeared in post injection specimens. Five of the women had allotype specific Gm agglutinators. In three, these were found in the pretreatment specimens. No evidence of Rh sensitization was demonstrable in the eleven Rh immune globulin recipients who had circulating anti‐gamma globulins at the time of treatment. Our data indicates that the risk of sensitization to Gm and Inv factors is a function of the concentration of the antigen in the Rh immune globulin and the pheno‐type of the recipients.