Correlation between MLC stimulation and graft survival in living related and cadaver transplants

"Multiple MLC's" (parallel tests in recipient, donor and globulin-poor plasma) were performed in 211 consecutive transplant donor-recipient pairs(2) The two-way MLC's were performed on patients' lymphocytes before immunosuppression. All grafts regarded as "successful" were at risk for at least six months. Patients with a low MLC (Stimulation Index less than 8 times controls) usually had successful grafts (graft survival was 83% in related transplants and 76% in cadaver transplants). Patients with high MLC's had poor graft survival (0% graft survival in related transplants and 32% in cadaver transplants). An adjusted graft survival was calculated to exclude patients who died with normal renal function (serum creatinine less than 2 mg%). The adjusted graft survival was 91% for living related transplants and 88% for cadaver transplants. Falsely low MLC's occurred when the recipient's plasma contained low-titer cytotoxic antibodies. In 15 recipients of cadaver kidneys, the MLC in recipient plasma was significantly lower than MLC's in donor or globulin-poor plasma. Since the MLC when using cadaver donors was necessarily retrospective, the results were not known pre-transplant and all 15 grafts were rejected. In living related pairs, however, we were able to screen for such antibody activity and could avoid humoral presensitization and cellular compatibility.