CD79A and inflammatory bowel disease: Bacterial sequencing of IBD stool samples has yielded remarkable insights into the species targeted by IgA, allowing for functional validation of key commensal and pathobiont species, such as Clostridiales and Ruminococcaceae species in CD and Eubacterium dolichum in UC.56,57 Future studies will help to resolve microbial species targeted by IgG in IBD patients across disease subclasses.