• Age \>=18 years, male or female, non-limited by race or ethnicity.

• Confirmed diagnosis of MDS according to the World Health Organization (WHO) 5th edition classification, based on histopathology and cytogenetics.

• Risk stratification according to the Revised International Prognostic Scoring System (IPSS-R) must place the patient in the intermediate-, high-, or very high-risk category.

• Not candidates for or refuse allogeneic hematopoietic stem cell transplantation.

• Adequate hepatic function including alanine transaminase (ALT) and aspartate aminotransferase (AST )\<= 3 × upper limit of normal(ULN), and total bilirubin \<= 1.5 × ULN.

• Adequate renal function including serum creatinine \<= 2 × ULN or CrCl\>= 40mL/min.

• LVEF measured by echocardiogram is within the normal range (LVEF \> 50%).

• The subject must have one donor who is \>= 18 years old and HLA matched at 0-7/10 loci (i.e., at least 3 HLA loci must be mismatched). In addition, the donor voluntarily donates hematopoietic stem cells and signs the consent form.

• Each subject (or his/her legal representatives) must sign the Informed Consent Form (ICF), indicating that he/she understands the purpose and procedures of research, and is willing to participate in research.

• Donor inclusion criteria: The donor meets the institution's criteria for related peripheral blood hematopoietic stem cell donors. The donor must be able to tolerate the cell separation and collection process, and sign the Informed Consent Form.