CagA阳性幽门螺杆菌感染与上胃肠道疾病关系的研究

目的探讨CagA阳性幽门螺杆菌(Hp)感染与上胃肠道病变的关系;并观察Hp根除治疗后血清中抗CagAIgG抗体水平的变化.方法808例因上胃肠道症状而接受胃镜检查的病人,同时作Hp检查.对Hp感染者用ELISA方法检测血清中抗CagAIgG抗体;阳性者予含质子泵抑制剂(PPI)三联疗法根除治疗.其中60例根除治疗失败病人和120例根除成功病人在Hp根除治疗结束3个月和6个月时复查血清中抗CagAIgG抗体水平.结果在不同临床疾病中,慢性浅表性胃炎(CSG)、慢性萎缩性胃炎(CAG)、胃溃疡(GU)、十二指肠溃疡(DU)和胃癌(GC)感染Hp的病人中抗CagAIgG抗体阳性率分别为55.4%、70.5%、83.2%、90.8%、89.7%.后4组阳性率明显高于CSG组,后3组均明显高于CAG组;在不同程度的胃粘膜病变中,CSG、CAG、肠上皮化生(IM)、非典型增生(Dys)和GC感染Hp的病人中抗CagAIgG抗体的阳性率分别为43.0%、53.8%、77.6%、88.6%、89.7%.IM、Dys和GC组均明显高于CSG和CAG组;60例根除失败者在治疗前及治疗后3个月和6个月时血清中抗CagAIgG水平分别为(72±41)U/ml,(67±36)U/ml和(69±40)U/ml,治疗前后差异无显著意义,无一例转为阴性;120例根除治疗成功者治疗后3个月和6个月血清中抗CagAIgG水平平均由(69±38)U/ml分别下降至(47±30)U/ml和(32±15)U/ml,治疗后与治疗前比较差异均有显著意义,在治疗后3个月和6个月时分别有7.5%(9/120)和19.2%(23/120)的病人抗体转为阴性.结论CagA阳性的Hp可能导致更严重的上胃肠道疾病和更严重的胃粘膜病变;Hp根除治疗后血清中抗CagAIgG抗体水平明显下降,但下降较慢,不宜作为个体监测疗效的指标.

Relation between infection of CagA-positive Helicobacter pylori and upper gastrointestinal diseases

OBJECTIVE: To study the relation between infection of Helicobacter pylori strains expressing CagA and upper gastrointestinal diseases, and to assess the change of anti-CagA IgG antibody levels after eradication of H. pylori. METHODS: Gastric biopsy was conducted among eight hundred and eight patients who received endoscopy to determine the pathological changes of mucosa and infectious status of H. pylori. The presence of serum anti-CagA IgG was detected in each H. pylori-positive patient by ELISA. Eradication therapy by PPI was conducted to the H. pylori-positive individuals. The anti-CagA IgG levels were reexamined among 60 patients whose H. pylori infection failed to be eradicated and 120 patients whose H. pylori infection was successfully eradicated after 3 months and 6 months. RESULTS: The serum anti-CagA IgG-positive rates were 55.4%, 70.5%, 83.2%, 90.8% and 89.7% in H. pylori-positive patients with chronic superficial gastritis (CSG), chronic atrophic gastritis (CAG), gastric ulcer (GU), duodenal ulcer (DU), and gastric cancer (GC) respectively. The serum anti-CagA IgG-positive rates among the latter 4 groups were significantly higher than that in CSG group, and the serum anti-CagA IgG-positive rates among the latter 3 groups were significantly higher than that in CAG group. The serum anti-CagA IgG-positive rate among patients with CAG was significantly higher than that among patients with CSG (P < 0.05). The CagA-positive rates in the groups of intestinal metaplasia (IM), atypical hyperplasia and GC were significantly higher than those in the groups of CSG and CAG (P < 0.05). By the end of 3 and 6 months after the eradication therapy, the antibody level had decreased from a mean value of (69 +/- 38) U/ml to (47 +/- 30) U/ml and (32 +/- 15) U/ml among 120 patients with successful eradication and the serum antibody reverted to negative only in 23 cases from them. There was no significant change in serum anti-CagA IgG level among 60 patients without successful eradication. CONCLUSION: Infection with CagA-positive H. pylori strains is associated with an increased risk of developing more severe gastroduodenal diseases and more severe gastric mucosa lesions. Despite an overall significant decrease of anti-CagA IgG level in sera after H. pylori eradication, this serological method cannot be used to monitor individual treatment effect because the anti-CagA IgG level decreases slowly.