RELATION OF ANTI-??-GLOBULIN ANTIBODIES TO TRANSPLANTATION ANTIBODIES IN HUMAN RENAL ALLOGRAFT RECIPIENTS

SUMMARY The objective of this study was to find out whether IgM antibodies to γ-globulins formed by human renal graft recipients would combine with the patient's own IgG antibodies to histocompatibility antigens. Serological studies showed that this indeed is the case provided that the transplantation antibodies combine at first with their corresponding antigens. Apparently, molecular transformation of the IgG antibodies in the course of serological reaction is necessary to warrant their interaction with the autologous anti-γ-globulin antibodies. Sections of excised renal grafts were incubated with human Rh-positive erythrocytes sensitized by incomplete Rh antibodies. Adherence of erythrocytes to such sections revealed that, in many instances, renal grafts contained anti-γ-globulin antibodies presumably bound to IgG transplantation antibodies. It was pointed out that covering of IgG transplantation antibodies by IgM antibodies to γ-globulins may possibly interfere with complement-mediated cytotoxicity and “protect” the graft.