The improvement in one-year graft survival has allowed transplant centers to focus on long-term graft survival. A study of 665 primary cadaveric kidney transplants from a single center treated with cyclosporine demonstrated that patients did not develop chronic rejection if there was not an episode of acute rejection. This study is a retrospective review of 314 consecutive kidney transplants from a single center to determine if early, aggressive treatment of the first episode of acute rejection will improve graft survival without increasing recipient morbidity. The course of 314 consecutive kidney transplants performed during a 27-month period (245 CAD and 68 living-related) was studied. Demographic characteristics were equivalent between the two groups, and all patients received sequential quadruple immunosuppression using ALG and CsA. Patient and graft survivals at 2 years were 89.7% and 84%, respectively. At least one rejection episode occurred in 41% of the patients, one-half within 30 days of transplant. Rejection episodes were treated by oral prednisone taper, primary ALG or OKT3, or "rescue" therapy with ALG or OKT3. Graft survival in the 52 recipients treated with OKT3 for primary treatment of first rejection episode was 20% better than the 50 patients treated with PRED (P = 0.0847). Comparing the 39 recipients of primary CAD kidneys treated with primary OKT3 vs. 38 treated with PRED demonstrated a 32% improvement in 2-year graft survival (P = 0.033). There was no increase in second rejection episodes in patients treated with OKT3. Renal function was equivalent in patients with rejection regardless of type of antirejection therapy used. Of patients treated for rejection, 22% had symptomatic CMV infections, which were divided equally between the two groups. Eighty-two patients received a single course of OKT3, 28 received two courses, and 2 patients received OKT3 three times. Only two patients developed antimurine antibodies that required abandoning OKT3 for the treatment of rejection. This study clearly demonstrates that the early use of OKT3 as primary treatment of rejection results in significant improvement of 2-year graft survival in recipients of first CAD kidney transplants. There is no increase in episodes in CMV in patients treated with OKT3 as primary therapy and no increase in patient mortality. Early use of OKT3 does not prevent or decrease incidence of subsequent rejection episodes. Renal function in surviving grafts is not improved in patients treated with OKT3 vs. PRED.(ABSTRACT TRUNCATED AT 400 WORDS)