Early Lymphocyte Recovery Predicts Superior Overall Survival After Unmanipulated Haploidentical Blood and Marrow Transplantation for MDS and Acute Myeloid Leukemia Evolving From MDS

Early lymphocyte recovery has shown to be associated with superior survival in patients with hematological malignancies following umanipulated haploidentical blood and marrow transplantion (HBMT), but its effect on clinical outcomes in patients with myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML) evolving from MDS is not known. We investigated the relationship between early lymphocyte recovery and transplant outcomes in 78 paients with MDS and AML evolving from MDS receiving T-cell-repleted transplantation from an haploidentical related donors. The median patient follow-up was 510 days (range, 15-3419 days). Higher relapse rate was observed in patients with an day 30 absolute lymphocyte count (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 had bacteria 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). In multivariate analysis, patients with a higher the ALC-30 (300 cells/μL) had improved overall survival (HR 0.099, 95% CI 0.029-0.337; P<0.0001), leukemia free survival (HR 0.271, 95% CI 0.122-0.602; P<0.0001), less relapse (HR 0.096 95% CI 0.011-0.827; P=0.033), and less transplant-related mortality (TRM, HR=0.073; 95% CI 0.016-0.324; P=0.001). A three human leukocyte antigen loci mismatch was associated with a higher incidence of TRM (HR 5.026 95% CI 1.392-18.173; P=0.014). Our results suggest that a higher ALC-30 (≥ 300 cells/μL) could be a useful and simple tool to predict MDS and AML evolving from MDS patients with a superior outcome after unmanipulated HBMT.