Further evidence to prove this, is the involvement of CXCL2 in Chemokine signaling pathways, TNF signaling pathway, Salmonella infection, and Legionellosis pathways (Supplementary Table S13), suggesting that this gene could play a role in the immunity and its up-regulation reported in this study may be due to the absence of F4R in non-adhesive small intestine epithelial cells. The gene discussed is TNF; the disease is legionellosis.