Donor-specific cellular and humoral immunity after clinical kidney transplantation

The cellular and humoral immune response against donor lymphocytes was studied in 10 patients transplanted with kidneys from living related donors. Nine of the grafts were functioning well at the time of the study. No direct (T) cell-mediated cytotoxicity against donor cells was demonstrated. Specific anti-donor antibodies were found in two recipients with well accepted grafts. Their antisera were active in antibody-induced cell-mediated cytotoxicity (AICC) and inhibited the mixed lymphocyte culture (MLC), but were negative in complement-dependent cytoxicity (CDC). Thus, no single immunological factor responsible for a favorable clinical course could be demonstrated. Neither complete T nor complete B cell tolerance against donor cells had developed, and a well tolerated graft could co-exist with antibodies directed against donor cells.