THE EFFECT OF RABBIT ANTITHYMOCYTE-SERUM (RATS) AND OKT3 ON PERIPHERAL-BLOOD MONONUCLEAR CELL SUBSETS FOLLOWING RENAL-TRANSPLANTATION

Fifty-five renal transplant recipients were studied prospectively for changes in monoclonal antibody-defined mononuclear cell subsets (MCS) over the first 45 days posttransplant. Patients received induction imm unotherapy with either monoclonal OKT2(n = 29) or polyclonal RATS (n = 26) preparation. Sequential examinations showed characteristic patter ns of MCS depletion, which differed according to the type of therapy r eceived and which subset was examined. In general, induction therapy w ith RATS resulted in greater and more sustained reduction of most MCS than was seen with OKT3 therapy. In recipients who received OKT3 induc tion there was a correlation between allograft rejection and an increa se in lymphocytes expressing pan-T cell markers and in natural-killer cells. In contrast, rejection episodes in patients receiving RATS were associated with increases in subpopulations of T cells including help er, inducer and suppressor/cytotoxic T-cell subsets. There was no corr elation of rejection with B cells or T-cell activation markers. The di fferent patterns of MCS depletion with different antilymphocyte prepar ations and the association between changes in different MCS and reject ion warrant further investigation.