[Relationship Between the Change of Microbial Diversity and Gastrointestinal Graft-Versus-Host Disease Following Allogeneic Hematopoietic Stem Cell Transplantation].

Objective: To investigate the change of microbial diversity and its relation with gastrointestinal (GI) graft-versus-host disease (GVHD) following allogeneic hematopoietic stem cell transplantation (allo-HSCT).

Methods: Fecal samples were collected at the time point of 2 weeks before transplantation (pre-transplant group), 1 month after transplantation (post-tranplant group) and onset of GI GVHD in 65 hematonosis patients, which were also collected in 26 donors and 10 healthy subjects (control group). 16S rRNA was extracted from fecal microbiotas whose V4 variable region was amplified. The amplification products were sequenced in Illumina HiSeq 2500 platform, and the sequencing results were analyzed and compared.

Results: The microbial diversity was 5.70（3.74, 10.60）in pre-transplant group, 7.30（4.89, 11.41）in control group, and the differences between them were not statistically significant. The microbial diversity was 3.88（2.39, 6.49）in post-transplant group, lower than that in control group and pre-transplant group. After transplantation, the microbial diversity was 4.24（2.47, 7.16）in the patients without GI GVHD, while the microbial diverosity was 2.90 (1.48, 5.64) in patients subsequently suffered from GI GVHD, but the differences between them were not statistically significant. The microbial diversity was 2.13（1.76, 3.75）onset of GI GVHD, which was lower than that without GI GVHD.

Conclusion: Intestinal microbial diversity decreases after allo-HSCT, and is associated with with Gl GVHD.