Moreover, IL-17-stimulated gastric epithelial cells produce the matrix metalloproteinase MMP-9 and the chemokines CCL25 and CXCL8 following contact with H. pylori, which contribute to tissue damage of gastritis and the infiltration of inflammatory cells (such as macrophage and neutrophil) (Shi et al., 2010). The gene discussed is IL17A; the disease is gastritis.