ITGB2 and irritable bowel syndrome: 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).