Gut microbiota and graft-versus-host disease in hematopoietic stem cell transplant patients.

Background and objectives: Graft-versus-host disease (GvHD) frequently complicates hematopoietic stem cell transplantation (HSCT). Emerging evidence suggests a correlation between gut microbiota and GvHD risk. This study aims to elucidate the microbiota profiles in HSCT patients before and after transplantation and their association with GvHD.

Materials and methods: This study, conducted from December 2022 to December 2023, involved the collection of 15 stool samples from HSCT patients. Bacterial content was quantified using real-time PCR, while interleukin-6 levels were assessed via ELISA.

Results: Among the 15 participants (8 male, 7 female), 9 underwent allogeneic HSCT (allo-HSCT) and 6 received autologous HSCT. In the aGvHD group, there was a significant reduction in the abundance of Bacteroides and Bifidobacterium compared to those without aGvHD. Additionally, declines were observed in Clostridium and Firmicutes populations. The genus Blautia also showed reduced prevalence in the aGvHD group, whereas no significant differences were noted in the uncomplicated group. ELISA analysis revealed that interleukin-6 levels remained within the normal range (30-960 pg/ml) with no significant elevation in the aGvHD group.

Conclusion: The study highlights a notable association between alterations in gut microbiota, specifically reductions in certain bacterial populations and the development of aGvHD following allo-HSCT.