This is a prospective study investigating the role of tissue-resident immune cell subsets in the occurrence and progression of graft-versus-host disease following hematopoietic stem cell transplantation. Approximately 40 subjects(including 20 grade 3-4 aGVHD patients and 20 grade 1-2 aGVHD patients ).

This study was a single-center, observational, prospective cohort study. The study lasted for 3 months, from 2024.11 to 2025.02.It is planned to enroll 40 subjects, divided into 20 grade 3-4 aGVHD patients and 20 grade 1-2 aGVHD patients. No randomization or any protocol-driven treatment will be performed or provided to subjects during the course of the study. Treatment decisions and selection of treatment options are left to the discretion of the treating physician, if clinically appropriate. All recipients will be followed for aGVHD evaluation,overall survival(OS) ,disease-free survival (DFS). aGVHD were graded according to published guidelines. All recipients will be monitored every month until the study is completed.

Inclusion Criteria:

1. Voluntarily sign the informed consent form;
2. Age 16-65 years old
3. Clinically diagnosed with GVHD for the first time/receiving GVHD treatment.

Exclusion Criteria:

1. Have a history of other tumors
2. With poor compliance or mental disorders
3. Infected with HIV and HCV
4. With uncontrolled HBV infection
5. With other autoimmune diseases
6. Those who are judged by the researcher to be unsuitable to participate in this study

Patients develop acute graft-versus-disease after hematopoietic stem cell transplantation.