NFKB1 and inflammatory bowel disease: Changes in its function will make the host more susceptible to infection with fungi (241), In the Aspergillus fumigatus infection model, the CARD9S12N mutation will be connected to CLR to activate the non-canonical NF-κB pathway, thereby producing a type 2 immune response (221), At the same time, CARD9S12N is also related to the intestinal microbial composition of IBD patients, with a strong correlation, particularly in patients with homozygous mutations in CARD9S12N, where almost no Pichia is present in the sigmoid colon (242).