Several of these IBD susceptibility genes are involved in neutrophil functions essential for microbial defense, including NOD2, NCF4, LRRK2, and CARD9. 611 The administration of yeast-produced GM-CSF has been found to improve some symptoms of Crohn’s disease and ileitis in mice.612 These results indicate that targeting neutrophil-microbiota crosstalk presents a promising therapeutic strategy for IBD. This evidence concerns the gene CARD9 and inflammatory bowel disease.