Inclusion Criteria:  Platelet count ≤ 30 × 10^9/L persistently at day 60 post-HSCT or later; Neutrophil and hemoglobin were well recovered; Full donor chimerism was achieved;  Exclusion Criteria:  Patients with malignancy relapse; Active infections; Grade Ⅲ-Ⅳ acute graft-versus-host disease or severe chronic graft-versus-host disease according to National Institute of Health criteria; Severe organ damage; Thrombosis requiring treatment;