Prolonged Hematogone Expansion Is Associated with Better Outcomes in Allogeneic Hematopoietic Stem Cell Transplantation Recipients

Background/Objectives: Hematogones, B cell precursors, are considered a clock of bone marrow reconstitution after chemotherapy and hematopoietic stem cell transplantation (HSCT). Methods: In this retrospective observational monocentric study, we investigated the prognostic role of hematogone expansion after allogeneic HSCT and its association with clinical and molecular features. Results: Using a cut-off value of 0.1%, hematogones were detected in 60% of patients at the first re-evaluation after HSCT (median, 2.4%; range, 0.2-9.0%) and in 63% of subjects at the most recent evaluation (MRR) (median, 1.4%; range, 0.1-5.1%). In particular, prolonged hematogone expansion was associated with longer overall survival (p = 0.0043) and relapse-free survival (p = 0.0002). No associations were described between hematogone frequency and stem cell sources or acute or chronic graft versus host disease incidence. Conclusions: In conclusion, our results confirmed that hematogones mirrored bone marrow fitness and reconstitution ability; thus, they could be used as a prognostic marker of HSCT outcomes.