Rh immunization following incompatible blood transfusion and a possible long-term complication of anti-D immunoglobulin therapy.

Anti-D immunoglobulin is now widely used to prevent Rh-negative mothers from being sensitized by Rh-positive fetal erythrocytes. The administration of anti-D following the transfusion of large amounts of Rh-positive erythrocytes into Rh-negative individuals has been less uniformly successful in preventing primary immunization (Bowman and Chown, 1968), and occasional mild (Woodrow et al, 1968) or severe (de Veber, 1968) reactions to plasma containing anti-D have been noted. The present case report demonstrates that while a large dose of anti-D immunoglobulin may be given with safety, a patient who is already weakly sensitized to the D antigen will subsequently show a rapid secondary immune response. Furthermore, a complication of unknown importance is the development of a positive direct anti-human globulin reaction on the patient's red cells; this reaction appearing 6 months after the immunoglobulin treatment.