Clinical impact of hematogones on outcomes of allogeneic hematopoietic stem cell transplantation

Increased levels of normal B cell precursors, termed hematogones (HGs), are observed in regenerating bone marrow after chemotherapy or hematopoietic stem cell transplantation (HSCT). Recent reports suggest that emergence of HGs is associated with better outcomes following allogeneic HSCT (allo-HSCT). We reviewed the emergence of HGs and the clinical features of 192 patients after allo-BMT. Patients undergoing allo-BMT from related donors were more likely to develop HGs at day 30 compared to unrelated donors. Furthermore, patients undergoing allo-BMT from HLA-mismatched donors were less likely to develop HGs at day 30. The emergence of HGs at day 30 was an independent prognostic factor among patients who underwent BMT. We found no difference in the relapse rate between HG-positive (+) and HG-negative (-) patients undergoing BMT. HG (-) patients had high non-relapse mortality, grade II to IV acute graft-versus-host-disease (GVHD), fungal infection, and lower IgG levels compared to HG (+) patients. The emergence of HGs at day 30 among patients undergoing BMT may be a very useful indicator of subsequent survival outcomes or acute GVHD in common clinical practice.