The purpose of this study is to evaluate the efficacy of hematopoietic stem cell microtransplantation for in acute myeloid leukemia (AML)patients who can not receive hematopoietic stem cell transplantation (HSCT).

Despite allogeneic HSCT is the only curative therapy for AML, some patients can not receive transplantation due to intolerance of transplant-related toxicity or unwillingness of HSCT. For these patients, microtransplantation seems an optional therapy. However, the efficacy still remain unclear.

Inclusion Criteria:

• AML patients who have received induction chemotherapy with moderate-high dose Ara-C and 3 courses consolidate chemotherapy
• Intolerance or unwillingness of allogeneic HSCT
• Subjects (or their legally acceptable representatives) must have signed an informed consent document indicating that they understand the purpose of and procedures required for the study and are willing to participate in the study

Exclusion Criteria:

• Any abnormality in a vital sign (e.g., heart rate, respiratory rate, or blood pressure)
• Patients with any conditions not suitable for the trial (investigators' decision)