AIM:To evaluate the predictive value of neutrophil infiltration as a marker of Helicobacter pylori(H.pylori) infection.METHODS:A total of 315 patients with dyspepsia symptoms who underwent upper gastrointestinal endoscopy were enrolled in this study.Biopsies were evaluated using the updated Sydney system.The medication history of all patients in the preceding 4 wk was recorded.The diagnosis of H.pylori infection was based on 13 C-urea breath test at least 4 wk after withdrawal of antisecretory drugs,antibiotics and related drugs.For the patients with subtotal gastrectomy,the diagnosis of H.pylori infection was based on anti-H.pylori immunoglobulin G(IgG) antibody.Serum anti-H.pylori IgG antibody was measured by enzyme-linked immunosorbent assays(Biohit,Finland).RESULTS:The sensitivity,specificity,positive predictive value and negative predictive value of neutrophil infiltration in the diagnosis of H.pylori infection were 92.3%,83.5%,77.4% and 94.7%,respectively.Neutrophil infiltration of gastric mucosa in the histological analysis was strongly associated with H.pylori infection(77.4% vs 5.3% in the neutrophil infiltration negative group,P = 0.000).Moderate neutrophil infiltration was more frequent in H.pylori infection when compared to mild infiltration(81.8% and 75%,respectively),but did not reach statistical significance.For those patients with negative rapid urease test,H.pylori was detected in 73.2% of patients with positive neutrophil infiltration on histology.In patients with subtotal gastrectomy,the diagnostic accuracy of neutrophil infiltration inH.pylori infection was 50%.CONCLUSION:Neutrophil infiltration is closely associated with H.pylori and may be recognized as a sign of this infection. AIM: To evaluate the predictive value of neutrophil infiltration as a marker of Helicobacter pylori (H. pylori) infection. METHODS: A total of 315 patients with dyspepsia symptoms who underwent upper gastrointestinal endoscopy were enrolled in this study. Biopsies were evaluated using the updated Sydney system. The medication history of all patients in the preceding 4 wk was recorded. The diagnosis of H. pylori infection was based on 13 C-urea breath test at least 4 wk after withdrawal of antisecretory drugs, antibiotics and related drugs. For the patients with subtotal gastrectomy, the diagnosis of H. pylori infection was based on anti-H. pylori immunoglobulin G (IgG) antibody. Serum anti-H. pylori IgG antibody was measured by enzyme-linked immunosorbent assays (Biohit, Finland) : The sensitivity, specificity, positive predictive value and negative predictive value of neutrophil infiltration in the diagnosis of H. pylori infection were 92.3%, 83.5%, 77.4% and 94.7%, respectively. Neutrophil infiltration of gastric mucosa in the histological analysis was strongly associated with H. pylori infection (77.4% vs 5.3% in the neutrophil infiltration negative group, P = 0.000). Moderate neutrophil infiltration was more frequent in H. pylori infection when compared to mild infiltration 81.8% and 75%, respectively), but did not reach the significance statistics. For those patients with negative rapid urease test, H. pylori was detected in 73.2% of patients with positive neutrophil infiltration on histology. In patients with subtotal gastrectomy, the diagnostic accuracy of neutrophil infiltration in H. pylori infection was 50%. CONCLUSION: Neutrophil infiltration is closely associated with H. pylori and may be recognized as a sign of this infection.