Clinical impact of absolute lymphocyte count on day 30 after unmanipulated haploidentical blood and marrow transplantation for pediatric patients with hematological malignancies.

Currently, limited information is available regarding the effects of early lymphocyte recovery on transplant outcomes in pediatric patients with hematological malignancies after unmanipulated haploidentical transplantation. In this study, we evaluated the association of Day 30 absolute lymphocyte count (ALC-30) with transplant outcomes in 60 consecutive pediatric patients with hematological malignancies receiving T-cell-repleted transplantation from an haploidentical related donors. After median follow-up of 36 months (range, 1.4-75 months), higher relapse rate was observed in patients with an ALC-30 < 300 cells/μL compared to patients with an ALC-30 ≥ 300 cells/μL (35.5% vs. 13.8%, P = 0.049). More patients died of infections in those with an ALC-30 < 300 cells/μL compared with patients with an ALC-30 ≥ 300 cells/μL (25.8% vs. 3.4%, P = 0.015). The ALC-30 above the cutoff value 300 cells/μL was associated with improved overall-survival (HR 0.301, 95% CI 0.117-0.771; P = 0.012), leukemia free survival (HR 0.195, 95% CI 0.078-0.498; P=0.002), less relapse (HR 0.224 95% CI 0.070-0.717; P = 0.012), and less transplant- related mortality (HR=0.166; 95%CI 0.037-0.750; P = 0.020). Our results suggest that a higher ALC-30 ≥ 300 cells/μL) could be a useful and simple tool to predict pediatric patients with a superior outcome after unmanipulated haploidentical transplantation.