Fecal Microbiota Transplantation for Acute Graft-versus-Host Disease after Allogeneic Hematopoietic Cell Transplantation: Expanding the Horizon into Pediatrics

The microbiome plays a vital role in maintaining homeostasis of the intestinal microenvironment and the immune response in allogeneic hematopoietic cell transplantation (HCT) recipients. Disruption of the intestinal microbiome has been associated with the development of acute graft-versus-host disease (GVHD) of the lower gastrointestinal tract and worse survival. Fecal microbiota transplantation (FMT) can achieve clinical responses in refractory GVHD, establishing the promise of microbiome-directed interventions in this population. Although most data on microbial changes in HCT recipients have been generated from the adult population, children with refractory GVHD represent an important group that may benefit from FMT. In this review, we first highlight characteristics that distinguish the pediatric intestinal microbiome from the adult intestinal microbiome. We then explore multiple clinical factors that warrant careful consideration to optimize the application of FMT and other microbiome-directed therapeutics to children.