[Key players in intestinal GVHD]

Acute graft versus host disease (GVHD) is a potentially life threatening complication after allogeneic hematopoietic stem cell transplantation. The gut is one of the most frequently affected organs in GVHD. Intestinal GVHD is often resistant to current therapies for GVHD and greatly affects the nutritional status of patients. Recent advances in understanding the biology of the intestinal immune system have revealed the significance of mechanical and chemical barriers involving the intestinal mucosa and intestinal microflora in the pathophysiology of GVHD. These barriers and flora are tightly regulated by key populations such as intestinal stem cells, Paneth cells, innate lymphoid cells, and macrophages. Recent findings for these key players in the process of intestinal GVHD are reviewed in this article.