PREVENTION OF ACUTE REJECTION EPISODES WITH AN ANTI-INTERLEUKIN-2 RECEPTOR MONOCLONAL-ANTIBODY .2. RESULTS AFTER A 2ND KIDNEY-TRANSPLANTATION

The focus of progress in transplantation immunosuppression is to achie ve more specific immunosuppression with monoclonal antibodies. We have already shown that the efficacy of 33B3.1, a rat monoclonal Ig2A dire cted against the human IL-2 receptor, was similar to that of rabbit an tithymocyte globulin in the prevention of acute rejection in first kid ney transplants. A similar comparative analysis has been made in 40-se c renal transplants. ATG (1 mg/kg/day) or 33B3.1 (10 mg/day) was admin istered during the first 10 days postgrafting in association with cort icosteroids and azathioprine. Cyclosporine was introduced on day 9 and azathioprine/CsA constituted the patient's maintenance treatment afte r day 45. Rejection treatment consisted of equine antilymphocyte globu lin in both cases and of steroid boluses when patients were under Cycl osporine. One patient in each group died. Graft survival was 90%, 85%, and 79% in the ATG group (n=20) and 100%, 89%, and 89% in the 33B3.1 group (n=20) at 3, 12, and 24 months, respectively. Of the ATG group p atients, 45% and 40% in the 33B3.1 group had at least one rejection ep isode, half the episodes in the MoAb cohort occurring under 33B3.1, vs . none in the ATG group. Transplant function was similar in both group s. Viral infections appeared to be more frequent with ATG (60%) than w ith 33B3.1 (12%), with CMV accounting for half of these in the ATG gro up, and none in the MoAb group. Tolerance of both agents was good. Of the 33B3.1 recipients, 70% developed anti-33B3.1 antibodies. From thes e data, we conclude that this anti-IL-2 receptor MoAb seems less effec tive than rabbit ATG as induction treatment in second kidney transplan t patients.