Immunological aspects of intrauterine transfusion.

Two cases of intrauterine transfusion were studied with reference to the viability and fate of donor lymphocytes. In one of the infants donor lymphocytes were found in cord blood in significant numbers, suggesting the presence of a degree of immunological tolerance. Though lymphocyte chimerism may occur after foetal transfusion, the absence of associated graft-versus-host reactions in the great majority of babies so treated implies that an immunological protection mechanism develops by at least the second half of gestation.Cord serum immunoglobulins were normal in both cases except for the presence of IgA, presumably due to the passive transfer of donor protein.The opportunity afforded by intrauterine transfusion for the study of foetal immunology is stressed. It is suggested that, in our present state of knowledge and in view of the small risk of graft-versus-host reaction, such studies should have precedence over efforts to remove immunologically active cells and protein from transfusion blood, especially since such efforts may impair the efficacy of the procedure.