This research project delves into the critical role of gut immunity in the occurrence and progression of acute graft-versus-host disease (aGVHD) post allogeneic hematopoietic stem cell transplantation (allo-HSCT). Addressing the current gaps in understanding the involvement of intestinal microbiota, metabolites, and cellular metabolism in clinical aGVHD, the study involves comprehensive analyses on 200 allo-HSCT patients and 50 healthy volunteers. By scrutinizing changes in gut microbiota, metabolites, and immune cell metabolism, the research aims to shed light on their roles in allo-HSCT and their correlation with post-transplant complications. The findings are poised to offer crucial insights for diagnosing and prognosticating complications following transplantation.

The intestinal immune system plays a pivotal role in the onset, progression, and evolution of acute graft-versus-host disease (aGVHD) following allogeneic hematopoietic stem cell transplantation (allo-HSCT). However, the precise contributions and mechanisms underlying the involvement of intestinal microbiota, metabolites, and cellular metabolism in immune regulation during clinical aGVHD remain unclear.

This research initiative aims to collect peripheral blood, fecal, and urine samples from 200 patients before and after transplantation as well as 50 healthy volunteers. Comprehensive analyses, including metagenomics, 16S rRNA sequencing, transcriptomics, metabolomics, single-cell sequencing, as well as assessments of immune cell function and inflammatory cytokines, will be conducted. Additionally, longitudinal follow-up observations will be performed to monitor post-transplant complications, relapse and immune reconstitution.

By investigating the dynamics of gut microbiota, metabolites, and cellular metabolism and analyzing their correlation with changes in immune responses, this study seeks to elucidate the roles of intestinal microbiota, metabolites, and immune cell metabolism in the context of allo-HSCT. The findings are anticipated to provide insights into the correlation between these factors and outcomes of allo-HSCT patients, contributing valuable evidence for the diagnosis and prognosis assessment of complications following transplantation.

Inclusion Criteria:

• Patients with hematologic disorders undergoing allo-HSCT.

Exclusion Criteria:

• Patients with confirmed pathogenic intestinal infections and severe systemic infections at the time of sampling.
• Diagnosis of autoimmune diseases, metabolic disorders, and chronic gastrointestinal diseases.
• Pre-transplant diseases not in complete remission.
• Post-transplant hematopoietic engraftment failure or pre-engraftment mortality.

Hematological patients will receive allo-HSCT in short time.