HALF DOSE OF OKT3 IS EFFICIENT IN TREATMENT OF STEROID-RESISTANT RENAL-ALLOGRAFT REJECTION

Rejection episodes in renal allograft recipients are usually efficient ly treated with high doses of intravenous methylprednisolone, Rejectio n therapy with OKT3 is often reserved for steroid-resistant episodes. However, the optimal dose of OKT3 in the treatment of steroid-resistan t rejection is not known. Therefore, we randomized renal transplant re cipients with steroid-resistant rejection to treatment with a standard daily intravenous dose of either 5 mg of OKT3 (n=15) or 2.5 mg of OKT 3 (n=15) for 10 days. Circulating T cells (measured as CD2(+) cells) w ere adequately and equally depleted in the two groups, Three grafts we re lost due to rejection within the first 3 months following OKT3 admi nistration, one in the 2.5 mg OKT3 group and two in the 5 mg OKT3 grou p. Two nonimmunologic graft losses occurred in the 2.5 mg OKT3 group. Median serum creatinine values were not different between the two grou ps, neither at the start (median values: 200 mu mol/L in the 5 mg OKT3 group vs. 188 mu mol/L in the 2.5 mg group) nor immediately after OKT 3 rescue therapy (202 mu mol/L vs, 185 mu mol/L, respectively), Eight cytomegalovirus infections occurred in each group. Two re-rejection ep isodes occurred in the 5 mg OKT3 group and one occurred in the 2.5 mg OKT3 group. All responded to treatment. Function of the remaining graf ts estimated by serum creatinine after a mean long-term follow-up of 1 8 months (range, 6-36 months) revealed no differences (185 mu mol/L in the 5 mg OKT3 group vs, 170 mu mol/L in the 2.5 mg OKT3 group). We co nclude that OKT3 treatment of steroid-resistant rejections in renal tr ansplant recipients is equally effective in daily doses of 2.5 mg and 5 mg with respect to reversal rate and long-term outcome.