Impact of donor-derived CD34 + infused cell dose on outcomes of patients undergoing allo-HCT following reduced intensity regimen for myelofibrosis: a study from the Chronic Malignancies Working Party of the EBMT

The optimal CD34 + cell dose in the setting of RIC allo-HCT for myelofibrosis (MF) remains unknown. We retrospectively analyzed 657 patients with primary or secondary MF transplanted with use of peripheral blood (PB) stem cells after fludarabine/melphalan or fludarabine/busulfan RIC regimen. Median patient age was 58 (range, 22–76) years. Donors were HLA-identical sibling (MSD) or unrelated (UD). Median follow-up was 46 (2–194) months. Patients transplanted with higher doses of CD34 + cells (>7.0 × 10 6 /kg), had an increased chance of achievement of both neutrophil (hazard ratio (HR), 1.46; P