Characterization of a novel Helicobacter pylori East Asian-type CagA ELISA for detecting patients infected with various cagA genotypes.

Currently, Western-type CagA is used in most commercial Helicobacter pylori CagA ELISA kits for CagA detection rather than East Asian-type CagA. We evaluated the ability of the East Asian-type CagA ELISA developed by our group to detect anti-CagA antibody in patients infected with different cagA genotypes of H. pylori from four different countries in South Asia and Southeast Asia. The recombinant CagA protein was expressed and later purified using GST-tag affinity chromatography. The East Asian-type CagA-immobilized ELISA was used to measure the levels of anti-CagA antibody in 750 serum samples from Bhutan, Indonesia, Myanmar, and Bangladesh. The cutoff value of the serum antibody in each country was determined via Receiver-Operating Characteristic (ROC) analysis. The cutoff values were different among the four countries studied (Bhutan, 18.16 U/mL; Indonesia, 6.01 U/mL; Myanmar, 10.57 U/mL; and Bangladesh, 6.19 U/mL). Our ELISA had better sensitivity, specificity, and accuracy of anti-CagA antibody detection in subjects predominantly infected with East Asian-type CagA H. pylori (Bhutan and Indonesia) than in those infected with Western-type CagA H. pylori predominant (Myanmar and Bangladesh). We found positive correlations between the anti-CagA antibody and antral monocyte infiltration in subjects from all four countries. There was no significant association between bacterial density and the anti-CagA antibody in the antrum or the corpus. The East Asian-type CagA ELISA had improved detection of the anti-CagA antibody in subjects infected with East Asian-type CagA H. pylori. The East Asian-type CagA ELISA should, therefore, be used in populations predominantly infected with East Asian-type CagA.

Differences in Helicobacter pylori and CagA antibody changes after eradication between subjects developing and not developing gastric cancer.

We evaluated serological Helicobacter pylori and cytotoxin-associated gene A (CagA) antibodies and endoscopic atrophy after eradication to identify factors predicting post-eradication gastric cancer development. Thirty-five patients with successful eradiation were divided into the post-eradication gastric cancer (13 cases) and non-gastric cancer (22 cases) groups. Serum Helicobacter pylori and CagA antibody titers and endoscopic atrophy before and six years after eradication were examined. Median Helicobacter pylori antibody titers had decreased significantly from baseline at 0.5-2 years after eradication in both groups (gastric cancer group, from 39.0 to 11.0 U/ml, p = 0.011; non-gastric cancer group, from 29.6 to 4.97 U/ml, p<0.001), but were significantly higher in the gastric cancer than in the non-gastric cancer group (p = 0.029). Median serum CagA antibody titers had also decreased significantly at 0.5-2 years after eradication (gastric cancer group, from 6.35 to 3.23 U/ml, p = 0.028; non-gastric cancer group, from 9.88 to 1.21 U/ml, p = 0.0045). Serum CagA in each group showed no significance. Endoscopic atrophy improved significantly after eradication in the non-gastric cancer, but not the gastric cancer, group (p = 0.0007). In conclusion, changes in Helicobacter pylori and CagA antibody titers and endoscopic atrophy after eradication might be useful as predictive factors for post-eradication gastric cancer.

The validation of the Helicobacter pylori CagA typing by immunohistochemistry: nationwide application in Indonesia.

We aimed to validate 2 types of antibodies, anti-CagA antibody and anti-East Asian CagA specific antibody (α-EAS antibody) for the determination of CagA status in Indonesia. We also confirmed the performance of α-EAS antibody for the detection of East Asian-type CagA H. pylori. Immunohistochemistry was performed using anti-CagA antibody and α-EAS antibody on gastric biopsy specimens from a total of 967 Indonesian patients. Diagnostic values of immunohistochemistry were evaluated with PCR-based sequencing as gold standard. Anti-CagA antibody had high sensitivity, specificity, and accuracy (87.0 %, 100 %, and 98.8 %, respectively) for determining CagA status. The α-EAS antibody was not suitable for the purpose of CagA status determination, as it had a low sensitivity (23.9 %). High specificity (97.6 %) but low sensitivity (41.2 %) and accuracy (66.3 %) was observed in α-EAS antibody to detect East Asian-type CagA. Patients with positive result of immunohistochemistry using anti-CagA antibody had significantly higher monocyte infiltration score in antrum (P < 0.001) and corpus (P = 0.009). In conclusion, the anti-CagA antibody is still suitable to be used in Indonesia for determining the CagA status, whilst the α-EAS antibody was not appropriate to discriminate between East Asian-type and non-East Asian-type CagA in Indonesia.

Novel CagA ELISA exhibits enhanced sensitivity of Helicobacter pylori CagA antibody.

AIM: To develop a novel Helicobacter pylori (H. pylori) CagA antibody enzyme-linked immunosorbent assay (ELISA) suitable for detecting serum anti-CagA antibodies with high sensitivity. METHODS: Recombinant East Asian-type CagA protein was purified and immobilized for ELISA. Serum samples from 217 Vietnamese individuals (110 H. pylori-infected and 107 uninfected individuals) were applied. Conventional ELISA from Western-type CagA and our East Asian-type CagA ELISA were evaluated by comparing 38 subjects with the Western-type genotype and 72 subjects with the East Asian-type cagA genotype. Histological scores of the gastric mucosa were determined using the updated Sydney System to examine the relationship with anti-CagA antibody titers. RESULTS: Recombinant 70-100 kDa fragments were immobilized on the ELISA plate. In ROC analysis, the area under the curve of our East Asian-type CagA ELISA was comparable to that of conventional CagA ELISA. The sensitivity of the two ELISAs differed depending on the cagA genotype. The sensitivity of East Asian-type CagA ELISA was higher for subjects infected with East Asian-type cagA H. pylori (P < 0.001), and the sensitivity of the conventional CagA ELISA tended to be higher for subjects infected with Western cagA H. pylori (P = 0.056). The titer of anti-CagA antibody tended to correlate with monocyte infiltration scores (r = 0.25, P = 0.058) and was inversely correlated with H. pylori density (r = -0.26, P = 0.043). CONCLUSION: The novel ELISA is useful to detect anti-CagA antibodies in East Asian countries, and the titer may be a marker for predicting chronic gastritis.

Association of Helicobacter Pylori Infection and Ectopic Pregnancy.

OBJECTIVE: To evaluate the importance of cytokine type in embryo implantation in uterus specified and activated macrophages interfere the tube movements and embryo retention in uterine tubes by smooth muscle relaxation and disrupting ciliary function. Therefore, increased risk of infection with HP during pregnancy, we investigated relation between Helicobacter pylori (HP) infection and prevalence of ectopic pregnancy (EP) in this study. MATERIALS AND METHODS: This is cross-sectional study from March 2012 to May 2013. Totally 207 women were enrolled randomly from which 101 had EP (Case group) and 106 were selected as control group with normal pregnancy. A 2-cc blood sample was taken from each patient to evaluate the specific IgG titer by ELISA method. All results of samples with positive H. pylori IgG were assayed for anti-CagA, IgG antibodies. A questionnaire was filled for each subject. The associations between CagA positive cases with odds of Ectopic pregnancy incidence were analyzed by using SPSS software, ver. 19 (Chicago, IL, USA). RESULTS: Mean (± SD) of age were 21.0 ± 5.78 and 30.78 ± 5.10 years for cases and controls group respectively. These groups didn't show any significance difference in age and parity.H. pylori IgG antibodies were positive among 99 and 103 (98.2% vs. 97.2%) in women with EP and normal pregnancy respectively. Relationship between IgG status and EP was not significant (OR = 1.31: 95% CI = 0.7-2.52, Pvalue = 0.37). In particular anti-CagA antibodies were positive among 45 and 39(45.92% vs. 36.97%) in women with EP and normal pregnancy respectively. Among women with CagA positive strains had higher odds of Ep (OR = 1.46: 95% CI = 0.8-2.65, Pvalue = 0.18), but it wasn't significant. CONCLUSION: According to the result of this study there was not any association between HP infection and Ectopic pregnancy. We recommend more studies with larger sample size for determining the effect of CagA positive strains on EP.

Insights into the Role of Helicobacter pylori Infection in Preeclampsia: From the Bench to the Bedside.

Preeclampsia (PE) is defined as a hypertensive and coagulative disorder affecting about 2-8% of all pregnancies and is one of the main causes of maternal and fetal morbidity and mortality. Despite the great amount of studies run in this field, little is known about the precise pathogenic mechanisms behind PE. While endothelial and trophoblast dysfunctions, exaggerated inflammatory response, and hypercoagulative state have been shown to play a key role in the occurrence of PE, the primary trigger is still unknown. One of the hypotheses is that some infectious agents may represent a trigger for PE onset. Consistently, higher seroprevalence of Helicobacter pylori (HP) infection, a Gram-negative bacterium with a specific tropism for human gastric mucosa, has been shown in women with PE. Even tighter association has been found between PE and infection with cytotoxin-associated gene-A (CagA)-positive strains of HP. Recent in vitro studies have shown that anti-CagA antibodies cross-react with human trophoblast cells and determine a functional impairment in terms of cell invasiveness, thus, providing the first pathogenic model of HP infection-mediated placental damage. Since in the early process of implantation and placental development, trophoblast invasion of maternal decidua is a crucial step, the proposed autoimmune mechanism induced by HP infection, negatively interfering with the fetal side of the early developing placenta, may represent a mechanism explaining the higher seropositivity for HP infection among PE women. However, the contribution of HP infection to the pathogenesis of PE or to the worsening of its clinical presentation need to be further investigated as well as the possible impact of pre-pregnancy screening and eradication of HP infection on the incidence of the syndrome.

Investigation on Relationship between Different Helicobacter pylori Antibodies and Gastric Cancer,Peptic Ulcer and Chronic Gastritis in Xinjiang Area / 胃肠病学

Background:Helicobacter pylori( Hp)is the main cause of chronic gastritis( CG),and CagA and VacA are important pathogenic factors of Hp. Recent studies have indicated that CagA and VacA antibodies of Hp have close relationship with gastric cancer(GC)and peptic ulcer(PU). Aims:To investigate the relationship between different antibodies of Hp and GC,PU and CG in Xinjiang area. Methods:Eighty-four GC,108 PU and 196 CG patients from Jan. 2014 to Aug. 2014 were enrolled. 14 C-urea breath test was used to determine Hp infection. Hp was typed by immunoblotting technique. Relationship between different Hp antibodies and patients with GC,PU and CG was analyzed. Results:Type Ⅰ Hp-positive rate in GC,PU and CG groups was decreased stepwisely(47. 6% ,37. 0% ,21. 4% , respectively). The positive rates of Hp strains(CagA-128 kDa,VacA-110 kDa and UreB-66 kDa)differed significantly among GC,PU,and CG groups(P = 0. 013,P = 0. 011,P = 0. 002);GC was associated with CagA-128 kDa,VacA-110 kDa,VacA-90 kDa and UreB-66 kDa(P < 0. 05),PU was associated with VacA-110 kDa,UreB-66 kDa(P < 0. 05). UreB-66 kDa was the risk factor of PU and GC(P < 0. 05). Conclusions:GC is associated with CagA-128 kDa,VacA-110 kDa,VacA-90 kDa and UreB-66 kDa,PU is associated with VacA-110 kDa,UreB-66 kDa,and UreB-66 kDa is the risk factor of PU and GC.