Immunosuppressive Total Nodal Irradiation–Based Reconditioning Regimens After Graft Rejection or Graft Failure in Pediatric Patients Treated With Myeloablative Allogeneic Hematopoietic Cell Transplantation

Abstract

This retrospective analysis aimed to address the efficacy of total nodal irradiation (TNI)-based reconditioning regimens in pediatric patients with graft failure/rejection after allogeneic hematopoietic cell transplantation. Thirty-three pediatric patients with malignant (n=25) and nonmalignant diseases (n=8) were treated with a TNI-based reconditioning regimen. All patients received a 7-Gy single dose combined with anti-T lymphocyte antibody OKT3 (n=16), anti-thymocyte globulin (n=24), fludarabine (n=31), and/or thiotepa (n=28), followed by an infusion of peripheral blood stem cells (n=31) or bone marrow transplant (n=2). Twenty-eight of 33 patients had haploidentical family donors. After a median of 11days, engraftment was seen in 32 of 33 children. Two children died 34days after retransplantation because of either disease relapse or treatment-related multiple organ failure. Severe acute toxicity was reported in only 1 child (systemic inflammatory response syndrome-like reaction; recovery after cortisone treatment). The average follow-up was 60.2months (range, 1.1-162.5months). Event-free and overall survival rates at 2/5years follow-up were 62.0%/58.6% and 65.1%/61.7%, respectively. Despite sustained engraftment, 12 patients died from disease relapse (n=3), Moschkowitz syndrome (n=1), or multiple organ failure (n=8). Follow-up data were available for 18 of 21 survivors, with a median follow-up of 92.8months (range, 3.6-162.5months). Hypothyroidism was present in 78.6% of patients, and sex/growth hormonal insufficiencies were reported for 37.5%. Mean forced expiratory volume in 1second after TNI was 84%; mean vital capacity was 79%. Severe growth failure (<3rd percentile) occurred in 28.6% (height) and 35.7% (weight) of patients. No secondary malignancies were reported. In the high-risk group of patients with graft failure/rejection after allogeneic hematopoietic cell transplantation, the TNI-based reconditioning regimen seems to allow sustained engraftment combined with a favorable toxicity profile, leading to long-term event-free and overall survival. Late toxicity after a median follow-up of over 7.5years includes growth failure, manageable hormonal deficiencies, and a low risk of decrease of lung function.