Decreased RBCTs after reduced intensity conditioning allogeneic stem cell transplantation: predictive value of prior Hb level

BACKGROUND: RBCT (RBCT) requirements of stem cell transplant (SCT) recipients are often substantial and may be related to transplant type. STUDY DESIGN AND METHODS: An analysis was done of RBCT requirements and Hb recovery kinetic in the first 60 days after HLA-identical sibling allogeneic SCT in a series of 110 consecutive patients treated for various malignant diagnoses. Patients were prepared with either an antithymocyte globulin (ATG) and reduced intensity chemotherapy-based conditioning (RIC) (n = 64) or a myeloablative conditioning regimens (MAC; n = 46). Patients received marrow (n = 64) or PBPCs (n = 46). RESULTS: Overall, intensity of conditioning regimen (RIC vs. MAC; p = 0.0005) and graft source (PBPC vs. marrow; p < 0.0001) independently predicted RBCT requirements. Hb recovery was accelerated after RIC when compared to MAC allo-SCT (p = 0.02). In RIC patients, RBCTs were inversely correlated to Hb level before conditioning (p < 0.0001) and the dose of ATG (p = 0.009). Moreover, Hb level before allo-SCT significantly influenced Hb recovery kinetic after RIC but had no impact on RBCT requirements and Hb recovery after MAC. CONCLUSION: Thus, RIC conditioning creates a different pattern of erythropoiesis recovery as compared to a MAC regimen and suggest a need for studies aimed at further reducing RBCT and accelerating Hb recovery.