Day + 100 bone marrow megakaryocyte count predicts transplant outcome in patients with high-risk myelodysplastic syndrome and acute leukemia.

Megakaryocytes (MKs), the precursor cells of platelets, have essential roles in a variety of pathophysiological processes in the bone marrow (BM) niche. Megakaryocytes maintain hematopoietic stem cell microenvironment through inflammatory and immunological responses. The primary objective of this research was to investigate the clinical impact of BM-MK counts in high-risk myelodysplastic syndrome and acute leukemia patients who underwent allogeneic hematopoietic stem cell transplantation (alloHSCT). Three hundred and forty-six patients (median age, 42 (15-71) years; male/female, 207/139) participated in the study. Based on the BM-MK counts on day + 100 of alloHSCT, the study population was classified into normal/high-MK+100 and low-MK+100 groups. The probabilities of progression-free survival (PFS) and overall survival (OS) were significantly better in the normal/high-MK+100 group (p < 0.001, p < 0.001). Nonrelapse mortality was found to be reduced in the same group of patients (p = 0.012). BM-MK+100 count, which was indicated to be a predictor for relapse after alloHSCT (p = 0.018), represented a considerable impact on PFS and OS (p = 0.017, p = 0.009). Megakaryocytes have regulatory roles in association with a comprehensive cytokine network in the BM microenvironment. Although the localization of MKs may be determinative for their spectrum of efficacy, distinct biological subgroups may also help to clarify the heterogeneity of their functional features. Prospective efforts in larger populations are required to illuminate the potential prognostic role of MKs in alloHSCT recipients.