[Expanding Role of Gastroenterologists in Acute Gastrointestinal Graft-versus-Host Disease: From Diagnosis and Management to Microbiome-Based Strategies].

Acute graft-versus-host disease (GVHD) is a major complication following allogeneic hematopoietic stem cell transplantation. Steroid-refractory cases have poor outcomes, so an accurate diagnosis, particularly differentiation from cytomegalovirus colitis, is critical. Ruxolitinib is the standard second-line therapy, while Vedolizumab has shown potential in gut-specific modulation. Recent studies have reported that reduced microbiome diversity and the loss of short-chain fatty acid-producing bacteria are linked to acute GVHD severity and mortality. Fecal microbiota transplantation may offer benefit in selected steroid-refractory cases, but the evidence remains limited and variable. Gastroenterologists play an essential role in diagnosis and microbiome-guided care. A personalized approach incorporating microbial biomarkers may improve the future outcomes.