Accordingly, we found that ITGB2 (CD18) as well as ITGAM (CD11b, a marker that is consistently expressed on cell surface of neutrophils41), two subunits of αMβ2 integrin, were the most significantly increased MLI microbiome-associated human proteins in IBD and both also were hub proteins in the network of differentially abundant MLI human proteins identified in this study (Fig. 6b). Here, ITGAM is linked to irritable bowel syndrome.