OBJECTIVETo evaluate the toxicity of conditioning regimens of modified Bu/Cy +/- antithymocyte (ATG) in early stage after allogeneic hematopoietic stem cell transplantation (allo-HSCT).

METHODSA hundred patients with hematological malignancies undergoing allo-HSCT were assessed. Forty-two patients (group A) were conditioned with modified Bu/Cy regimen, 58 (group B) with modified Bu/Cy+ATG regimen. The occurrence of toxicity during the early stage after transplantation was evaluated and compared, including non-infectious fever, diarrhea, hepatotoxicity, mucositis and hematological toxicity.

RESULTSIn group A and B, the incidence of non-infectious fever was 4.8% vs 81.0%, transaminase elevation 59.5% vs 65.5%, bilirubin elevation 16.7% vs 48.3%, diarrhea 59.5% vs 79.3% and mucositis 45.2% vs 37.9%, respectively, white blood cells reached zero occurred at a median of +3 d and -3 d, the rate of red cell and platelet transfusion-dependence, within 10 days before transplantation was 11.9% vs 32.8 and 16.7% vs 82.8%, respectively.

CONCLUSIONSSignificant higher incidence of non-infectious fever, diarrhea, hepatotoxicity, leukopenia, and transfusion dependence is found and considered to be related to the administration of ATG in the conditioning regimen.