Background: More children are coming to heart transplantation on extracorporeal membrane oxygenation (ECMO), or inotropic support and/or with renal impairment. The use of basiliximab, a chimeric monoclonal antibody against CD25 (interleukin 2 receptor alfa) has not been previously reported in critically ill pediatric heart transplant recipients. Basiliximab has potential advantages in the treatment of patients with renal impairment.
Methods: Basiliximab was provided to 29 patients (median age 7.8 years; range 0.4-16 years) on ECMO, with renal impairment or receiving intravenous inotropes at transplantation. Children normally received 2 doses on Day 0 and Day 4 after transplantation. Calcineurin inhibitor was provided in low dose or withheld altogether in patients with renal impairment. Flow cytometry was used to monitor CD25.
Results: At transplantation, 11 patients were prescribed cyclosporine; the remaining 18 received tacrolimus. All but 4 patients had subtherapeutic levels of calcineurin inhibitor in the first postoperative week. Excluding these 4, there were 19 patients who had more than 4 consecutive doses of calcineurin inhibitor canceled in the first week (median 8 doses; range 3-40 doses). A total of 71 surveillance biopsies were performed, and 4 episodes of severe acute rejection occurred in the first 6 months. In all but one child, the glomerular filtration rate had returned to, or improved on baseline measurement by 1 month after transplantation. Infections rates were low and acceptable. CD25 was undetectable at first assessment, and in all but 1 patient (on ECMO) for at least 2 to 3 weeks thereafter. There were no adverse effects.
Conclusions: Basiliximab was well tolerated in this group of very ill children. In children with pre- or postoperative renal dysfunction, where doses of calcineurin inhibitor were low or canceled, basiliximab was associated with a low incidence of rejection. Posttransplant ECMO may reduce the efficacy of basiliximab. These preliminary results are encouraging and now need confirmation in a large, randomized trial.