REVIEW

Gut microbiota and allogeneic transplantation Weilin Wang1,2,3†, Shaoyan Xu1,2,3†, Zhigang Ren1,2,3, Jianwen Jiang1,2,3 and Shusen Zheng1,2,3* The latest high-throughput sequencing technologies show that there are more than 1000 types of microbiota in the human gut. These microbes are not only important to maintain human health, but also closely related to the occur-rence and development of various diseases. With the development of transplantation technologies, allogeneic trans-plantation has become an effective therapy for a variety of end-stage diseases. However, complications after trans-plantation still restrict its further development. Post-transplantation complications are closely associated with a host’s immune system. There is also an interaction between a person’s gut microbiota and immune system. Recently, animal and human studies have shown that gut microbial populations and diversity are altered after allogeneic transplanta-tions, such as liver transplantation (LT), small bowel transplantation (SBT), kidney transplantation (KT) and hemat-opoietic stem cell transplantation (HTCT). Moreover, when complications, such as infection, rejection and graft versus host disease (GVHD) occur, gut microbial populations and diversity present a significant dysbiosis. Several animal and clinical studies have demonstrated that taking probiotics and prebiotics can effectively regulate gut microbiota an