The composition of the intestinal microbiota after allogeneic haematopoietic stem cell transplantation and its association with graft versus host disease as assessed by 16Sribosomal ribonucleic acid.

To observe the evolution of the intestinal microbiota in patients after allogeneic hematopoietic stem cell transplantation (allo-HSCT) and discuss the relationship between the intestinal microbiota and graft-versus-host disease (GVHD). In this study, 11 patients who underwent allo-HSCT in the Aerospace Central Hospital from January 2021 to October 2021 were selected, along with 11 donors. Fecal specimens were collected 7 times: at admission, after pre-treatment, and every 3 weeks after transplantation from patients and once from donors. The composition of the intestinal microbiota and its association with GVHD after allogeneic hematopoietic stem cell transplantation were analyzed by 16S rRNA sequencing. Of the 11 patients, 5 developed GVHD, and 6 did not. The diversity of the intestinal microbiota among GVHD patients first increased and then decreased after transplantation, while that among non-GVHD patients first increased and then tended to be stable. The diversity of the intestinal microbiota among GVHD patients was lower than that among non-GVHD patients before pre-treatment and after transplantation. The taxa diversity of the intestinal microbiota in the non-GVHD group was better than that in the GVHD group before allo-HSCT, and the difference was statistically significant (P<0.05 for OTUs and CHAO1 index). The taxa abundance of Enterococcaceae 2.16% (2.13%, 2.22%) before allo-HSCT was significantly higher than that in the non-GVHD group 1.33% (0.27%, 1.52%), and the difference was statistically significant (P=0.004). There was no significant difference between the GVHD group and the non-GVHD group in the diversity of the intestinal microbiota of donors (P<0.05). The characteristics of the intestinal microbiota in the final sample of patients in the GVHD group were similar to the preoperative structure of the intestinal microbiota. In conclusion: The decrease in the diversity of the intestinal microbiota after HSCT may be a risk factor for the occurrence of GVHD. The presence of Enterococcaceae in the intestinal microbiota may be associated with an increased risk of developing GVHD. The intestinal microbiota reconstitute to be close to the intestinal microbiota composition of the donors in the non-GVHD group.