Type Ⅰ and type Ⅱ Helicobacter pylori infection status and their impact on gastrin and pepsinogen level in a gastric cancer prevalent area

BACKGROUND Type I Helicobacter pylori(H.pylori)infection causes severe gastric inflammation and is a predisposing factor for gastric carcinogenesis.However,its infection status in stepwise gastric disease progression in this gastric cancer prevalent area has not been evaluated;it is also not known its impact on commonly used epidemiological gastric cancer risk markers such as gastrin-17(G-17)and pepsinogens(PGs)during clinical practice.AIM To explore the prevalence of type I and type II H.pylori infection status and their impact on G-17 and PG levels in clinical practice.METHODS Thirty-five hundred and seventy-two hospital admitted patients with upper gastrointestinal symptoms were examined,and 523 patients were enrolled in this study.H.pylori infection was confirmed by both 13C-urea breath test and serological assay.Patients were divided into non-atrophic gastritis(NAG),nonatrophic gastritis with erosion(NAGE),chronic atrophic gastritis(CAG),peptic ulcers(PU)and gastric cancer(GC)groups.Their serological G-17,PG I and PG II values and PG I/PG II ratio were also measured.RESULTS A total H.pylori infection rate of 3572 examined patients was 75.9%,the infection rate of 523 enrolled patients was 76.9%,among which type I H.pylori infection accounted for 72.4%(291/402)and type II was 27.6%;88.4%of GC patients were H.pylori positive,and 84.2%of them were type I infection,only 11.6%of GC patients were H.pylori negative.Infection rates of type I H.pylori in NAG,NAGE,CAG,PU and GC groups were 67.9%,62.7%,79.7%,77.6%and 84.2%,respectively.H.pylori infection resulted in significantly higher G-17 and PG II values and decreased PG I/PG II ratio.Both types of H.pylori induced higher G-17 level,but type I strain infection resulted in an increased PG II level and decreased PG I/PG II ratio in NAG,NAGE and CAG groups over uninfected controls.Overall PG I levels showed no difference among all disease groups and in the presence or absence of H.pylori;in stratified analysis,its level was increased in GC and PU patients in H.pylori and type I H.pylori-positive groups.CONCLUSION Type I H.pylori infection is the major form of infection in this geographic region,and a very low percentage(11.6%)of GC patients are not infected by H.pylori.Both types of H.pylori induce an increase in G-17 level,while type I H.pylori is the major strain that affects PG I and PG IIs level and PG I/PG II ratio in stepwise chronic gastric disease.The data provide insights into H.pylori infection status and indicate the necessity and urgency for bacteria eradication and disease prevention in clinical practice.