Butyrate Supplementation Is Associated With Gut Microbiome Modulation and Reduced Acute GVHD After Allogeneic HSCT

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is an effective treatment for blood cancers, but it is often complicated by acute graft-versus-host disease (aGVHD), a serious immune-related condition associated with disruption of the gut microbiome.In this prospective clinical study, we evaluated whether oral sodium butyrate supplementation influences gut microbial composition and clinical outcomes after allo-HSCT. Patients receiving butyrate showed a significantly lower cumulative incidence of grade II-IV aGVHD compared to controls, with a marked reduction in severe (grade III-IV) and lower gastrointestinal aGVHD.Metagenomic sequencing revealed that butyrate-treated patients maintained a more stable gut microbial structure after transplantation. Specific bacterial species, including Bacteroides thetaiotaomicron and Tyzzerella nexilis, were more abundant in the butyrate group and were not detected in patients who developed severe aGVHD. Stool metabolite analysis further demonstrated selective recovery of fecal butyric acid levels in the treatment group.These data suggest that postbiotic-based modulation of the gut microbiome may reduce the risk of acute GVHD and support microbial recovery following allo-HSCT.