A Novel Unifrac-Based Analytical Method for Determining Sequential Changes in Gut Microbiota after Hematopoietic Stem Cell Transplantation

The human gut harbors various microorganisms, which are important for maintenance of systemic health, including metabolism and immune system homeostasis. Recent studies demonstrated the association of intestinal flora with various diseases such as inflammatory bowel disease and rheumatoid arthritis. In addition, studies on patients with hematopoietic stem cell transplantation (HSCT) showed that the variation in intestinal bacterial flora after transplantation is related to prognosis, frequency of infection, sensitivity to antimicrobial agents, and severity of graft versus host disease. Nonetheless, most studies showing less diversity of intestinal flora evaluated patients' feces a certain period after HSCT. In order to determine the relationship between the alterations in intestinal flora composition and the clinical course post-HSCT, we used metagenomic analysis to evaluate the time-dependent changes in intestinal bacterial flora in patients undergoing allogeneic (allo) HSCT, and compared them with those of healthy controls (HC) or recipients of autologous (auto) peripheral blood HSCT.