Abbreviations: ATG, antithymocyte globulin; BM, bone marrow; Hb, hemoglobin; HCT, hematopoietic cell transplantation; HCT-CI, HCT-comorbidity index; IPSS, International Prognosis Scoring System; PB, peripheral blood; RAEB, refractory anemia with excess blasts; RCMD, refractory cytopenia with multilineage dysplasia; R-IPSS, revised IPSS; WBC, white blood cells; WHO, World Health Organization.