OKT3 Treatment of SteroidResistant Rejection in Pediatric Liver Transplant Recipients

Of a total of 187 consecutive liver grafts in 149 pediatric recipients, 59 episodes of steroid-resistant, biopsy-proven rejection (32 of grafts) were treated with OKT3 monoclonal antibody. After 59 OKT3-treated episodes, liver function at the end of treatment was normal in 40, improved in 35, and unchanged in 24. Of 21 partial responses, 12 episodes eventually resolved to yield an overall complete response rate of 59. CD3-positive T-cells >5 occurred during 61 of OKT3-treated rejection episodes and was associated with impaired efficacy of OKT3 (30 complete response rate). Six grafts were re-treated with OKT3 for rejection and in all CD3-positive T-cells could not be maintained <5. Of the six grafts requiring repeat OKT3, five failed-re-treatment and required retransplantation. OKT3 antibodies of low titer were found prior to a second use of OKT3 in 65 of episodes. Patients treated with OKT3 after failing more than two preceding steroid courses had a significantly increased chance of graft loss (57; p = 0.01). We conclude that this group of pediatric patients appeared less responsive to OKT3 compared to other series combining pediatric and adult recipients, possibly due to a more vigorous immune response in the child.