Increased risk of early rejection correlates with recovery of CD3 cell count after liver transplant in patients receiving OKT3 induction

Background. We evaluated the utility of CD3 cell counts for monitoring OKT3 induction immunosuppression and for predicting early rejection in liver recipients. Methods. In 32 adults in whom OKT3 and steroids were used to induce immunosuppression, CD3 cell subsets were labeled with CD3 (IgG1)- fluorescein isothiocyanate monoclonal antibody and assayed by flow cytometry before orthotopic liver transplantation and within 2-4 days, 5-7 days, and 8- 10 days after transplantation. Trough OKT3 levels were measured at the same points in 10 patients. Early rejection (before postoperative [POD] day 21) was proven by elevated liver function tests and biopsy; Six patients were excluded for death, retransplantation, or early cessation of OKT3. Results. Eight of 26 patients (30.8%) had early rejection and 18 (69.2%) had no early rejection. All had depletion of CD3 cells to <10.2% of baseline at POD 2-4. On POD 8-10, the mean CD3 count in rejectors was 213.31± 184.98/mm³ vs. 22.71±32.42/mm³ in nonrejectors (P<0.001). By POD 8-10, five of eight (62.5%) patients who rejected had CD3 count recovery to >75% of baseline. No nonrejecting patient recovered to >26% of baseline (P<0.001). OKT3 levels did not correlate with CD3 recovery or rejection. Conclusions. The incidence of early rejection correlates strongly with recovery of CD3 counts by POD 10. Higher baseline CD3 counts do not predict early rejection.