The duration of administration of monoclonal antibody OKT3 for induction immunosuppression after heart transplantation.

: The effective treatment of refractory allograft rejection with murine antihuman monoclonal antibody muromonab-CD3 (OKT3) and of patients with renal dysfunction has led to its use as induction therapy. The optimal protocol for OKT3 prophylaxis remains to be established. We compared 59 patients consecutively transplanted with the total orthotopic technique between 1/92 and 5/94. The first 21 patients were treated with OKT3 for 14 days, the next 19 for 10 days, and the last 19 for 7 days. Patients operated with different surgical techniques or other induction treatment were excluded. We compared length of stay (total and ICU), time to first rejection, rejection incidence and infection incidence (cytomegalovirus separately), and survival. Preoperative characteristics were similar except for significantly younger age in the 10-day group (p = 0.04). Preoperative hemodynamic parameters were similar except for a significantly higher left-ventricular ejection fraction (21%) in the 7-day group. Length of stays in the ICU and hospital were similar for the three groups (p = NS). Freedom from cellular rejection was lower with the 7 days course (p = 0.02), but freedom from humoral rejection was slightly higher (p = 0.11). However, patients in the 7-day group required treatment for rejection less frequently than patients in the other two groups (95% untreated at 2 months vs. 43% in the 14-day and 53% in the 10-day group; p = 0.002). There were no differences in incidence of infections, including cytomegalovirus. Survival was similar between the groups. There was one death in the 14-day and 1 in the 10-day group, both due to rejection. In conclusion, OKT3 therapy can be reduced safely to 7 days with a higher overall incidence of rejection but no increased necessity to treat for rejection, and no difference in infection incidence.