VA Conditioning Regimen Allo-HSCT for Elderly Higher-risk MDS

Inclusion Criteria: * The patient should, in the investigator's opinion, be able to meet all clinical trial requirements. * The patient is willing and able to adhere to the study visit schedule and other protocol requirements. * The patient should be diagnosed with higher risk MDS according to the standard criteria of the World Health Organization (WHO). Exclusion Criteria: * Active or uncontrolled infections requiring systemic treatment within 14 days before enrollment. * Any instability of systemic disease, including but not limited to severe cardiac, liver, kidney, or metabolic disease need therapy.