CXCR2 and colitis: As Cxcr2 has previously been shown to regulate G-MDSC infiltration in lower GI/colitis disease models (21), we assessed the frequency of gastric G-MDSC and non-G-MDSC myeloid cells, in S100a8Cre/+Cxcr2flox/flox versus Cxcr2flox/flox mice, by FACS.