CARD9 and inflammatory bowel disease: Notably, M. restricta plays a pivotal role in the development of gut inflammation and cancer (Spatz and Richard, 2020).Particularly, M. restricta is abundantly present in inflammatory bowel disease patients harboring loss-of-function mutations in caspase recruitment domain-containing protein 9 (Card9), a phenomenon that triggers a robust inflammatory response from myeloid phagocytes.