Fecal microbiota transplantation in inflammatory bowel disease: the quest for the holy grail

Inflammatory bowel disease (IBD) is due to an aberrant immune response toward luminal antigens, probably commensal bacteria, in genetically susceptible subjects and is also influenced by environmental factors. An imbalanced intestinal microbiota known as "dysbiosis," characterized by an increased proportion of pro-inflammatory microorganisms and a decreased proportion of anti-inflammatory microorganisms, has been repeatedly observed in IBD and is now recognized as a key factor in the gut inflammatory process. Fecal microbiota transplantation (FMT) has gained interest as a novel treatment option in IBD. The goal of FMT in IBD is not only to correct the dysbiosis, but also to restore a normal dialog between the host immune system and the microbiota. Data are still scarce, but the results of the first studies suggest that FMT could be a promising therapy in IBD. More studies are needed to define the best indications, optimal timing, frequency, mode of delivery, and the optimal donor for each patient.