To evaluate the possible biological effects of PAR1 in H. pylori–associated gastritis in vivo, we evaluated the inflammatory response in gastric mucosa on day 28 p.i. Compared with WT mice, Par1–/– mice showed significantly more inflammation (Figure 6G) and higher CD45+CD11b+Ly6C–Ly6G+ neutrophil infiltration (Figure 6H) in gastric mucosa. The gene discussed is ITGAM; the disease is gastritis.