Exploration of the relationship between intestinal flora changes and gut acute graft-versus-host disease after hematopoietic stem cell transplantation.

Background Acute graft-versus-host disease (aGVHD) is a life-threatening factor for post-hematopoietic stem cell transplantation (HSCT) patients. To investigate the relationship between intestinal flora changes and gut aGVHD after HSCT, we performed this cross-sectional study. Methods We selected children from our medical center from July 2016 to January 2017. Fifty-six samples from 42 patients and 6 samples from normal children met the study criteria and were analyzed. Fecal 16S RNA sequencing was completed before transplantation or on days 7, 28 or 100 post-transplantation. The intestinal infection and GVHD clinical data were retrospectively analyzed, and the survival risk factors were analyzed. Correlation analysis was performed with the feces bioinformatic data. Results The GVHD group alpha diversity was the lowest, which was significantly different than that of the non-diarrhea group (P value=0.032). A richer posttransplantation relative abundance of Moraxellaceae was conducive to survival, while that of Enterococcaceae and Alphaproteobacteria was not. Similarly, a rich relative abundance of Proteobacteria, Gammaproteobacteria and Odoribacteraceae in the intestinal flora before HSCT contributed to patient death thereafter. Regarding diarrhea, the GVHD group exhibited a richer Pasteurellales and Pasteurellaceae relative abundances, which showed strong correlations with diarrhea severity. Peptostreptococcaceae, Bifidobacteriales and Bifidobacteriaceae were richer in relative abundance in the intestinal infection group and correlated with pretransplant characteristics. Conclusions The gut microbiota diversity was lowest when gut aGVHD occurred, which was consistent with the clinically higher mortality rate and greater treatment difficulty. Pasteurellaceae played an important role in gut aGVHD and diarrhea severity. Bifidobacteriaceae led to infectious diarrhea after HSCT. Specific bacteria were biomarkers for survival: Moraxellaceae, Enterococcaceae and Alphaproteobacteria from the intestinal flora after HSCT and Proteobacteria, Gammaproteobacteria and Odoribacteraceae before HSCT.