Treatment of acute renal allograft rejection with OKT3 monoclonal antibody.

Eight cadaver donor renal allograft recipients, who had received azathioprine and prednisone from the day of transplantation, were treated with OKT3 monoclonal antibody (reactive with all mature peripheral blood T cells) at the time of diagnosis of acute rejection. In all cases, loss of essentially all detectable peripheral blood OKT3-reactive cells was noted within minutes after the initial 1- to 5-mg i.v. infusion. Chills and fever invariably occurred following the first or second infusion of monoclonal antibody, but were not noted during the subsequent, 10- to 20-day course of therapy, suggesting rapid cell lysis as the etiology of this toxicity. The established rejection episode was reversed in all cases within 2 to 7 days without addition of any therapy other than OKT3 antibody and despite continued lowering of the steroid dosages. During the subsequent 3- to 12-month follow-up period, further rejection episodes occurred in five of these patients, two of these were irreversible with conventional therapy so that six of the eight allografts continue with excellent renal function. These preliminary observations suggest that homogeneity, limited dosage requirements, and ease of in vitro monitoring of dosage effects should markedly simplify the use of monoclonal antibody to T cell populations in human allograft recipients. This second generation of antilymphocyte preparations offers the potential for not only increased effectiveness but also the possibility of manipulating specific T cell subsets.