



Researchers at Weill Cornell Medicine in New York suggest an impaired immune regulation of gut fungi may cause inflammatory bowel disease (IBD). The study, "CX3CR1+ mononuclear phagocytes control immunity to intestinal fungi," appeared in the journal Science. Gut microbes, collectively called the microbiome, have important roles in food digestion and metabolism. These microorganisms also interact with the immune system, and research has shown that failed regulation of the microbiome population by the immune system can cause IBD. Unlike most of the research work on the gut microbiome, which focuses on bacteria, the investigators studied fungi. The development of new techniques to analyze fungal DNA allows the previously difficult task of analyzing fungi, "and [researchers] have now taken this further by visualizing fungal-host interactions in the gut," Iliyan Iliev, PhD, the study’s senior author, said in a press release. In a previous study, Iliev and collaborators demonstrated that humans have a resident population of fungi (called the mycobiome) in the gut, which may play a role in IBD-associated ulcerative colitis. "After discovering that fungi might be involved in the pathology of IBD, one of the big questions in the field has been how to identify patients who would benefit from antifungal co-therapy, and our finding suggests a way to do that," Iliev said in the recent press release. Phagocytes are critical cells in host defense and immunity. They ingest foreign bodies such as bacteria, and generate an immune response by presenting fragments of these substances to other immune cells. The study shows that a type of white blood cell located in the gut — the CX3CR1+ mononuclear phagocyte — is the main initiator of the immune response to