Helicobacter pylori Genotypes and Expression of Gastritis in Erosive Gastro-oesophageal Reflux Disease

Background: Epidemiological studies suggest a negative association between Helicobacter pylori and gastro-oesophageal reflux disease (GORD). Moreover, cagA-positive strains are reported to protect from complications of GORD. The aim of this study was to determine virulence factors (cagA, vacA and iceA) of H. pylori strains and the pattern of gastritis in patients with GORD in comparison with patients with duodenal ulcer (DU) or functional dyspepsia (FD). Methods:H. pylori strains isolated from gastric biopsies of 105 consecutive patients with mild to moderate erosive GORD (n?=?35, LA grade A-B), and from sex- and age-matched patients with DU (n?=?35) or FD (n?=?35 without reflux symptoms) were investigated. CagA, vacA, and iceA genotypes were determined by PCR analysis of the isolates. Gastritis was classified in accordance with the updated Sydney classification. Results: The prevalence of all three H. pylori virulence factors was higher in patients with GORD (cagA[Formula: See Text] 80%, vacA s1 77%, iceA1 71%) and DU (cagA[Formula: See Text] 83%, vacA s1 80%, iceA1 74%) than in patients with FD (cagA[Formula: See Text] 40%, vacA s1 49%, iceA1 46%). Gastritis activity in the antrum and corpus did not differ between the three groups. However, lymphocytic infiltration of the gastric antral mucosa was more pronounced in DU patients than in those with GORD or FD. Conclusions:H. pylori strains obtained from patients with mild to moderate erosive GORD show a virulence pattern similar to that found in DU patients. The presence of these virulence factors does not appear to protect against erosive lesions in the oesophagus.     

Functional dyspepsia is associated with cagA-positive Helicobacter pylori strains

BACKGROUND: The antigen CagA can be used as a marker for virulence of Helicobacter pylori. It is tempting to assume that H. pylori strains positive for cytotoxin-associated gene A (cagA) could be responsible for functional dyspepsia. A cross-sectional study was performed in patients presenting with functional dyspepsia to correlate the clinical presentation with the presence of cagA-positive and -negative H. pylori strains. METHODS: Consecutive patients referred for endoscopy were studied. An inclusion criterion was the absence of any endoscopic abnormality. Biopsy specimens were obtained from the gastric antrum for HE and immunoperoxidase stain, rapid urease test, and culture. A serum sample was taken for detection of IgG antibodies against H. pylori as well as CagA. A validated questionnaire of 14 questions regarding the upper gastrointestinal tract was used for assessment of the clinical presentation. Nine questions were scored on a 5-point Likert scale. RESULTS: 422 patients were included, 222 were H. pylori-positive, the remaining 200 were H. pylori-negative. Mean symptom score in patients with cagA-positive strains was significantly higher than in patients with cagA-negative strains. No difference was present if cagA-negative patients were compared with H. pylori-negative dyspeptics. Four different complaints were more prevalent in the cagA-positive patients compared with cagA-negatives. When cagA-positive patients were compared with H. pylori-negative dyspeptics, seven complaints were significantly more prevalent in cagA-positives; when cagA-negatives were compared this number was only two. CONCLUSIONS: Functional dyspeptics with cagA-positive H. pylori strains have more dyspeptic symptoms and higher symptom scores than patients with cagA-negative H. pylori strains as well as H. pylori-negative functional dyspeptics.     

Helicobacter pylori CagA-positive Strains Affect Oxygen Free Radicals Generation by Gastric Mucosa

Background: Helicobacter pylori plays a key role in production of reactive oxygen metabolites (ROMs). However, the importance of virulent CagA-positive H. pylori strains remains to be determined. The aim of this study was to assess ROMs production in gastric biopsies of patients infected by H. pylori. Results were correlated to CagA status and acute inflammatory infiltration. Methods: Patients undergoing gastroscopy were enrolled. H. pylori infection was assessed by histology and ¹³C urea breath test. CagA status was assessed through serology. ROMs were assayed in gastric biopsies by luminol-enhanced chemiluminescence (CLS). Gastric mucosal inflammation was histologically graded and neutrophils were individually counted. Macroscopical damage was scored according to a modified Lanza score. Results: 40 out of 60 patients evaluated were H. pylori (HP) positive. Of the 40 infected patients, 24 were CagA-positive. CLS emission was significantly higher in HP-CagA-positive patients than in HP-CagA-negatives and uninfected. ROMs production showed a significant correlation to neutrophil infiltrate in all groups. Conclusions: Gastric mucosa of patients infected by HP-CagA-positive strains is characterized by a higher generation of ROMs and by greater neutrophil counts than that observed in HP-CagA-negative subjects. Since ROMs production is associated with DNA oxidative damage, a long-term stimulation by these strains might be relevant in the pathogenesis of gastric malignancies. Assessment of CagA status might be useful to discriminate patients in which H. pylori eradication is advisable.     

Augmented levels of gastric mucosal leucocyte activation by infection with cagA gene-positive Helicobacter pylori

The possession of the cytotoxin-associated gene (cagA) of Helicobacter pylori is thought to be highly associated with peptic ulcer disease. However, the pathogenic role of cagA is still unknown. We have emphasized the importance of the interrelationship between H. pylori-derived ammonia and oxygen radicals from in?ltrated leucocytes. The aim of the present study was to explore the relationship between oxygen radical production and H. pylori strain diversity based on cagA possession. An endoscopic examination and gastric mucosal biopsy were performed in 30 H. pylori-infected patients with gastric ulcer. Myeloperoxidase (MPO) content and the luminol-dependent chemiluminescence value in the biopsied gastric specimens were measured as an index for leucocyte in?ltration and oxygen radical production. From the precipitates of cultured bacterial isolates of biopsied specimens, bacterial DNA was puri?ed and analysed by polymerase chain reaction to characterize the possession of cagA. While all patients had ureC-positive strains, 22 had cagA-positive and eight had cagA-negative strains. In patients with cagA-positive strains, MPO contents as well as chemiluminescence values in the gastric corpus were signi?cantly higher than those in patients with cagA-negative strains. Gastric mucosal leucocyte recruitment and activation are suggested to be enhanced by cagA gene-positive H. pylori infection.     

Impact of Non-steroidal Anti-inflammatory Drug and Aspirin Use on the Prevalence of Dyspepsia and Uncomplicated Peptic Ulcer Disease

Background: Non-steroidal anti-inflammatory drug and aspirin (here collectively called NSAIDs) use is the second most common aetiologic factor for peptic ulcer disease and a major factor for peptic ulcer complications. The role of NSAIDs in the pathogenesis of uncomplicated peptic ulcer is less well understood and the interaction between NSAIDs and Helicobacter pylori infection on ulcer development is controversial. The aim of the present study was to examine the role of NSAIDs in the occurrence and clinical features of uncomplicated peptic ulcer disease. Methods: A total of 1091 consecutive patients referred for open-access upper gastrointestinal endoscopy by general practitioners (GPs) were enrolled. The use of NSAIDs was gathered from a structured questionnaire completed by the patients and from patient files by GPs. The exclusion criteria were previous H. pylori eradication and gastric surgery, as well as symptoms and/or signs suggestive of acute gastrointestinal bleeding. Results: Of the whole study group (n = 1091), 76 (7%) patients had a peptic ulcer. Thirty patients had an NSAID-use-associated peptic ulcer and 46 patients a non-NSAID-use peptic ulcer. Of patients with chronic gastritis (n = 599), 71% were H. pylori-positive and 108 used NSAIDs. Of those with chronic gastritis, 23 had an NSAID-use-associated peptic ulcer and 38 a non-NSAID ulcer. Of patients with normal gastric histology (n = 492), 75 patients used NSAIDs, 7 had an NSAID ulcer and 8 a non-NSAID ulcer. The only independent risk factor for peptic ulcer in patients using NSAIDs was H. pylori infection (odds ratio (OR) 3.1, 95% confidence interval (CI) 1.3-7.3), whereas dyspepsia (OR 1.0, 95% CI 0.4-2.4), male sex (OR 1.4, 95% CI 0.6-3.4), age (OR 1.0 per decade, 95% CI 0.8-1.3) and anaemia (OR 2.9, 95% CI 0.9-8.7) were not risk factors. In patients not using NSAIDs, independent risk factors for peptic ulcer were dyspepsia (OR 4.3, 95% CI 2.1-8.8), male sex (OR 2.0, 95% CI 1.1-2.8), age (OR 1.2 per decade, 95% CI 1.0-1.5), anaemia (OR 6.2, 95% CI 2.6-14.9) and H. pylori infection (OR 7.5, 95% CI 3.4-16.6). When comparing patients using NSAIDs or not, the OR of patients on NSAIDs for peptic ulcer was 2.7 (95% CI 1.5-5.0) among patients with chronic H. pylori gastritis (n = 424) and 5.3 (95% CI 1.8-15.0) among patients with normal gastric mucosa (n = 492). Conclusions: The use of NSAIDs increases the risk of peptic ulcer 3- and 5-fold in H. pylori-positive and H. pylori-negative patients, respectively. Dyspepsia is a poor predictor of peptic ulcer among patients using NSAIDs, and serologic H. pylori testing and treatment for chronic NSAID users is recommended.     

Discovery of unique African Helicobacter pylori CagA-multimerization motif in the Dominican Republic

BACKGROUND Helicobacter pylori (H. pylori) colonizes the human stomach and is a major cause of peptic ulcer disease and gastric cancer. However, although the prevalence of H. pylori is high in Africa, the incidence of gastric cancer is low, and this phenomenon is called to be African enigma. The CagA protein produced by H. pylori is the most studied virulence factor. The carcinogenic potential of CagA is associated with the Glu-Pro-Ile-Tyr-Ala (EPIYA) patterns and CagA-multimerization (CM) motifs.AIMTo better understand the EPIYA patterns and CM motifs of the cagA gene.METHODSGastric mucosal biopsy specimens were obtained from 258 patients with dyspepsia living in the Dominican Republic, from which 120 H. pylori strains were cultured. After the bacterial DNA extraction, the EPIYA pattern and CM motif genotypes were determined using a polymerase chain reaction-based sequencing. The population structure of the Dominican Republic strains was analyzed using multilocus sequence typing (MLST). Peptic ulcer disease and gastric cancer were identified via endoscopy, and gastric cancer was confirmed by histopathology. Histological scores of the gastric mucosa were evaluated using the updated Sydney system.RESULTSAll CagA-positive strains carried the Western-type CagA according to the identified EPIYA patterns. Twenty-seven kinds of CM motifs were observed. Although the typical Western CM motif (FPLKRHDKVDDLSKVG) was observed most frequently, the typical East Asian CM motif (FPLRRSAAVNDLSKVG) was not observed. However, “FPLRRSAKVEDLSKVG”, similar to the typical East Asian CM motif, was found in 21 strains. Since this type was significantly more frequent in strains classified as hpAfrica1 using MLST analysis (P = 0.034), we termed it Africa1-CM (Af1-CM). A few hpEurope strains carried the Af1-CM motif, but they had a significantly higher ancestral Africa1 component than that of those without the Af1-CM motif (P = 0.030). In 30 cagA-positive strains, the "GKDKGPE" motif was observed immediately upstream of the EPIYA motif in the EPIYA-A segment, and there was a significant association between strains with the hpAfrica1 population and those containing the “GKDKGPE” motif (P = 0.018). In contrast, there was no significant association between the CM motif patterns and histological scores and clinical outcomes.CONCLUSIONWe found the unique African CM motif in Western-type CagA and termed it Africa1-CM. The less toxicity of this motif could be one reason to explain the African enigma.     

Anti‐CagA and anti‐VacA antibodies in Helicobacter pylori‐infected patients with and without peptic ulcer disease in Serbia and Montenegro

Background: The expression of two Helicobacter pylori proteins, CagA and VacA, is associated with more severe pathogenesis and clinical outcomes of the infection. However, this association varies among geographical regions and ethnic groups. We therefore evaluated CagA and VacA seroprevalence in H. pylori‐positive dyspeptic patients in Serbia and Montenegro. Methods: In 173 consecutive dyspeptic patients referred to endoscopy (67M, mean age 49?±?15, 76 smokers), immunoblot assay was used to detect serum antibodies against CagA and VacA. Presence of H. pylori infection was assessed using a rapid urease test (RUT), routine histology and serology (anti‐IgG ELISA). Duodenal ulcer (DU) was diagnosed in 28, gastric ulcer (GU) in 3 and non‐ulcer dyspepsia (NUD) in the remaining 142 patients. Results: 129 (74.6%) patients were H. pylori‐positive, 27 (96.4%) with DU, 3 (100%) with GU and 99 (69.7%) with NUD (P?P?Conclusions: In Serbia and Montenegro there is high seroprevalence of CagA‐positive H. pylori strains in dyspeptic patients with and without peptic ulcer, while VacA‐positive strains are more closely related to peptic ulcer disease.     

Impact of Helicobacter pylori CagA diversity on gastric mucosal damage: an immunohistochemical study of East-Asian-type CagA

Background and Aims: Recently, we successfully produced an anti‐East‐Asian‐type CagA‐specific antibody called α‐EAS Ab, which is specifically immunoreactive only with East‐Asian‐type CagA but not Western‐type CagA. In this study, the correlations between Helicobacter pylori CagA protein diversity and gastric mucosal condition was investigated using immunohistochemical staining with α‐EAS Ab in Japan. Methods: There were 254 H. pylori‐positive patients enrolled in this study. α‐EAS Ab was used to determine the CagA phenotype instead of cagA sequencing, and, moreover, the histological findings and endoscopic gastric mucosal condition were evaluated according to the updated Sydney System and the Kimura–Takemoto classification system, respectively. Results: A total of 224 (88.2%) of the patients were immunoreactive for α‐EAS Ab. The remaining 30 (11.8%) were negative for α‐EAS Ab, suggesting that they were infected with either Western‐type CagA or CagA‐negative strains (i.e. non‐East‐Asian‐type CagA strains). The grades of activity of gastritis, mucosal atrophy and intestinal metaplasia according to the updated Sydney System were significantly higher in patients infected with East‐Asian‐type CagA strains than those infected with non‐East‐Asian‐type CagA strains. The grade of endoscopic gastric mucosal atrophy evaluated using the Kimura–Takemoto classification system was similar. All 28 strains isolated from patients with gastric cancer possessed the East‐Asian‐type CagA. Conclusions: Infection with East‐Asian‐type CagA H. pylori was more closely associated with gastric mucosal atrophy and gastric cancer than infection with non‐East‐Asian‐type CagA H. pylori. The efficiency of immunohistochemical analysis for CagA should be equivalent to that of cagA sequencing.     

Gastric mucosal cytokine levels in relation to host interleukin-1 polymorphisms and Helicobacter pylori cagA genotype

Objective The outcome of a Helicobacter pylori infection is related in part to interrelationships among H. pylori virulence factors and the H. pylori-induced mucosal response. The host inflammatory response is partly governed by polymorphisms in pro-inflammatory genes.

Material and methods Cytokine levels (interleukin (IL)-1β, IL-6 and IL-8) were examined in H. pylori-infected and uninfected normal-appearing mucosa from patients with non-ulcer dyspepsia (NUD), margins of gastric ulcers and cancer tissues. Cytokine levels were compared with cagA genotypes and host interleukin (IL)-1 polymorphisms.

Results The study comprised 168 Thai patients. All infected patients possessed anti-CagA antibody. Gastric mucosal IL-8 levels were significantly higher in H. pylori-positive cases than in -negative cases in all three tissue types (e.g. 1115 versus 217?pg/mg protein for NUD) (p<0.001). Normal-appearing but H. pylori-infected antral mucosa of patients with cagA type 1a strains had higher IL-8 levels than those with type 2a strains (2632 versus 1036 pg/mg protein) (p<0.005). IL-1B-511T/T carriers had higher antral mucosal IL-1β levels versus non-carriers (pg/mg protein) (T/T=221, T/C=178, C/C=70) (p=0.005). IL-1B-511T/T carriers also had higher IL-1β levels versus non-carriers in H. pylori-negative patients.

Conclusions It was found that both the host factors (IL-1 polymorphisms) and bacterial factors (cagA type 1a versus type 2a) influenced gastric mucosal cytokine levels. Future studies should concentrate on interactions among host factors (e.g. genetics and tissue responses) and bacterial and environmental factors.     

Increased Risk of Developing Atrophic Gastritis in Patients Infected with CagA+Helicobacter pylori

Background: To clarify the possible role of CagA positive (CagA⁺) Helicobacter pylori strains in the development of atrophic gastritis, the prevalence of antibodies to H. pylori and CagA (120 kD protein) was studied among subjects with atrophic and non-atrophic gastritis. Methods: The study population was randomly selected among 12,252 Finnish men who were screened for atrophic corpus gastritis with serum pepsinogen I-assay (S-PGI). S-PGI level was used as a selection criterion. Group A consisted of 295 subjects with S-PGI &lt;25 µg/l (low), group B of 320 subjects with S-PGI 25-100 µg/l (normal) and group C of 338 subjects with S-PGI &gt;100 µg/l (high). Antibodies to H. pylori were measured with EIA and immunoblot analysis and antibodies to CagA with immunoblot analysis. Endoscopical and histological examinations were performed for 203 patients from group A. Results: The prevalence of antibodies to H. pylori was significantly lower in group B than in groups A or C (P &lt; 0.0001, chi-squared test). There was a significant association between the prevalence of antibodies to CagA and the lowered level of S-PGI (P &lt; 0.0001, Jonckheere-Terpstra trend test). There was also a linear decrease in the prevalence of antibodies to CagA as the atrophic corpus gastritis became more severe (P &lt; 0.0001, linear-by-linear trend test). Conclusion: The presence of antibodies to CagA seems to be associated with development of atrophic corpus gastritis.     

Relationship between the diversity of the cagA gene of Helicobacter pylori and gastric cancer in Okinawa, Japan

Background Helicobacter pylori CagA protein is considered to be one of the virulence factors associated with gastric cancer. CagA is injected into gastric epithelial cells, undergoes tyrosine phosphorylation, and binds to Src homology 2 domain-containing protein-tyrosine phosphatase (SHP-2). Two major subtypes of CagA have been observed in the SHP-2-binding site, the Western and East Asian types. The East Asian-type CagA binds to SHP-2 more strongly than the Western-type CagA. The diversity of CagA, which collectively determines the binding affinity of CagA to SHP-2, may be an important variable in determining the clinical outcome of infection by different H. pylori strains. Methods We investigated the relationship between the diversity of CagA and clinical outcome in Okinawa, Japan. A total 24 strains, 13 gastric cancer strains and 11 duodenal ulcer strains, were studied. We sequenced full-length cagA genes and analyzed the phylogenetic relationships between Okinawa isolates and previously characterized Western H. pylori strains. Results All isolates examined were cagA positive. The prevalence of East Asian CagA-positive strains was significantly higher in patients with gastric cancer (84.6%) than in patients with duodenal ulcer (27.3%) (χ-squared = 8.06, P = 0.011). The phylogenetic analysis showed that all gastric cancer strains with East Asian-type CagA were in the East Asian cluster, and that most duodenal ulcer strains were in the Western cluster. Conclusions The origins of H. pylori isolates are different between gastric cancer strains and duodenal ulcer strains, and East Asian CagA-positive H. pylori infection is associated with gastric cancer. The strain diversity observed in Okinawa may affect the difference in the prevalence of disease associated with H. pylori infection in Japan.     

Patients with duodenal ulcer have lower levels of serum cholesterol compared to other dyspeptic patients independently of Helicobacter pylori status

Objective. The association between Helicobacter pylori (H. pylori) infection and serum lipid profile is still controversial. The aim of this study was to determine any possible relationship between H. pylori infection and the lipid profile of patients with upper gastrointestinal symptoms. Material and methods. Consecutively selected 20–70 year-old dyspeptic patients who had undergone esophagogastroduodenoscopy were evaluated for H. pylori infection using both the CLO test and Giemsa staining. Serum total cholesterol (C), HDL-C, LDL-C, apo-A₁, apo-B and triglyceride levels were measured. Results. A total of 137 patients (median age 52.0 years) were studied. Total cholesterol levels were lower in H. pylori-infected patients than in H. pylori-negative patients (mean±SEM: 199.3±5.9 versus 212.6±4.6 mg/dl, p=0.08). Patients with duodenal ulcer (DU) had significantly lower levels of all measured lipidemic parameters including cholesterol, with the exception of triglycerides, in comparison with either H. pylori-positive or -negative dyspeptic patients (cholesterol: 177.6±6.5 versus 214.6±4.2 mg/dl, p<0.0001). However, there was no difference in the total cholesterol/HDL-C ratio between DU patients and the rest of the dyspeptic patients. Conclusions. Among H. pylori-positive and H. pylori-negative patients there was no difference in lipid profile apart from a trend towards total cholesterol levels being lower in H. pylori-positive patients. However, cholesterol, HDL-C, LDL-C, apo-A and apo-B were all decreased in DU patients even though this reduction did not result in a fall in the total cholesterol/HDL-C ratio. The etiologic factor differentiating the lipid profiles among dyspeptics only in H. pylori-positive patients carrying a DU could be dietetic, microbial, genetic or a combination of all three.     

Intragastric Nitric Oxide/Nitrite in Helicobacter pylori-Infected Subjects

Background: Nitrite (NO₂-) in swallowed saliva is reduced to nitric oxide (NO) and other nitrogen oxides by the intragastric acidity. This mechanism is probably important for the intragastric clearance of ingested micro-organisms and nitrosating compounds. The study examines the balance between intragastric NO and NO₂- in relation to endogenous acid production and infection with Helicobacter pylori. Methods: Six healthy H. pylori-negative and six H. pylori-positive volunteers with no known gastroduodenal pathology were examined after an overnight fast. Gastric NO was measured using a chemiluminescence technique and pH as well as NO₂- were analysed in gastric aspirates. Results: Gastric NO was slightly lower in H. pylori     

Analysis of the 3′ Variable Region of the <Emphasis Type="Italic">cagA</Emphasis> Gene of <Emphasis Type="Italic">Helicobacter pylori</Emphasis> Isolated in Koreans

CagA protein of Helicobacter pylori is injected into epithelial cells, and it undergoes tyrosine phosphorylation, resulting in inducing cytoskeletal rearrangements. A few studies have suggested that the number of CagA tyrosine phosphorylation motifs (EPIYA) and subtypes of CagA were associated with gastric cancer. This study was performed to characterize the 3' variable regions of the cagA gene of H. pylori and to investigate whether or not there is any relationship between the diversities of cagA and the disease outcome in Korea. Seventy-nine patients (chronic gastritis, 15; duodenal ulcer, 27; benign gastric ulcer, 18; gastric cancer, 19) were enrolled. Biopsy specimens were taken from the antrum for H. pylori culture, and genomic DNA was extracted. PCR and DNA sequence analysis was carried out for the 3′ variable region of the cagA gene. Seventy-eight strains (98.8%) contained three EPIYA motifs and one strain (1.2%) isolated from a patient with duodenal ulcer contained four EPIYA motifs. Seventy-six strains (96.2%) were the East Asian type. In conclusion, there was no significant difference between the number of EPIYA motifs or CagA subtypes and various gastroduodenal diseases in Korea.     

<Emphasis Type="Italic">cagA</Emphasis> Gene and Protein Status Among Iranian <Emphasis Type="Italic">Helicobacter pylori</Emphasis> Strains

The wide geographic genetic diversity of Helicobacter pylori (Hp) and, in particular, the varying prevalence of cagA in different countries has been documented repeatedly. This study was designed to determine the frequency of cagA in Iranian Hp strains by means of genotyping and assessment of host antibodies. Helicobacter pylori strains from 235 patients, including 174 non-ulcer dyspepsia, 25 peptic ulcer and 36 gastric cancer patients, were studied. The frequencies of the 5′, middle and 3′ terminal regions of the cagA gene were 90.6, 57.6, 89%, respectively, with no correlation to the clinical outcomes. Antibodies against the CagA protein were present in 90.7% of patients. Multiple biopsy sampling in 97 cases revealed multiple infection in 16.5% of the patients. Sequencing of the seven variants of the 3′ end of the cagA gene revealed no clustering and the distribution of the Iranian strains among those of other countries. Our results from the genotyping and serology analyses confirm that the majority of Iranian Hp strains are cagA-positive.     

Persistence of Helicobacter pylori infection in patients with peptic ulcer perforation

Objective. In patients with perforated peptic ulcer (PPU) the convergence between the high eradication rate of Helicobacter pylori infection and low rates of ulcer relapse after treatment has been associated with reinfection by non-virulent strains. The objective of this study was to evaluate the persistence of infection by virulent H. pylori strains and ulcer recurrence in 33 patients with PPU one year after surgery and antimicrobial treatment. Material and methods. The histological evaluation and molecular detection of H. pylori cagA and ureA genes, vacA allelic types and the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analyses of the glmM gene products from antral mucosa specimens were performed initially, 2–5 months and 1 year after therapy. Results. The density of H. pylori colonization was temporarily decreased (p<0.05) 2–5 months after therapy. After one year, complete eradication was achieved in only 7 patients (23%) at histological examination and recurrent ulcers were found in 3/33 (9%) patients. The vacA s1a allelic type of cagA-positive strains persisted in 19/33 (58%) PPU patients with identical PCR-RFLP fingerprints in 8/9 (89%) of the patients. Conclusions. In PPU patients with a low eradication rate of H. pylori infection after surgical and antimicrobial treatment, the frequent recrudescence of the infection is mostly caused by the persisting virulent strains of the cagA and vacA s1a subtypes. In the 1-year follow-up period the recurrent ulceration can be postponed just by the lowered colonization density of H. pylori after eradicative therapy.     

Helicobacter pylori cagA Status and Peptic Ulcer Disease in Iran

Helicobacter pylori contributes to the development of peptic ulcers and atrophic gastritis. Furthermore, H. pylori strains carrying the cagA gene are more virulent than cagA -negative strains and are associated with the development of gastric adenocarcinoma. The cagA gene is a putative H. pylori virulence factor of unknown function. The aim of this study was to determine the prevalence of the cagA gene among H. pylori isolates and its relationship with peptic ulcer disease in 128 Iranian patients. A total of 107 (83.6%) samples were positive, including 40 (95%) of the 42 patients with duodenal ulcer, 43 (86%) of the 50 patients with gastric ulcer, and 24 (66.6%) of the 36 patients with gastritis. cagA was present in 32 (80%) of 40 strains from duodenal ulcer patients, 33 (77%) of 43 strains from gastric ulcer patients, and 11 (46%) of 24 from gastritis patients. We also attempted to investigate the subtypes of 3′ region of cagA gene in H. pylori strains isolated from Iranian patients and their relation to H. pylori-associated gastroduodenal diseases. The PCR product of cagA positive strains obtained with primer set CAG1/CAG2 differed in size, varying from 642 to 651 bp (subtype A) in 33 isolates to 756 bp (subtype B/D) in 13 isolates. This does not support the view that subtypes of the 3′ region of cagA gene in H. pylori isolated from Iran correlate with the clinical outcomes of H. pylori, but colonization with cagA positive strains was significantly higher among duodenal ulcer than gastritis patients in Iran.     

<Emphasis Type="Italic">Helicobacter pylori</Emphasis> CagA protein variation associated with gastric cancer in Asia

Recent molecular analysis has provided the pathological actions of CagA on gastric epithelial cells. CagA is injected into epithelial cells via the type IV secretion system and undergoes tyrosine phosphorylation in the cells. In addition, translocated CagA forms a physical complex with SHP-2. There are two major CagA subtypes; the East Asian and the Western type. The East Asian CagA protein possesses stronger SHP-2 binding activity than the Western CagA. The grades of inflammation, activity of gastritis, and atrophy are significantly higher in gastritis patients infected with the East Asian CagA-positive strain than in gastritis patients infected with the cagA-negative or Western CagA-positive strains. The prevalence of the East Asian CagA-positive strain is associated with the mortality rate of gastric cancer in Asia. Endemic circulation of H. pylori populations carrying biologically more active CagA proteins in East Asian countries, where the mortality rate of gastric cancer is among the highest in the world, may be involved in increasing the risk of gastric cancer in these populations.     

Association Between the IgG Subclass Response,Inflammation and Disease Status in Helicobacter pylori Infection

Background: In many viral, bacterial and parasitic infections the Immunoglobulin G (IgG) subclass response has been shown to correlate with severity of inflammation and disease outcome. The aim of the present study was to investigate the association between the IgG subclass response to Helicobacter pylori infection and disease and inflammation. Methods: Eighty-three symptomatic patients undergoing endoscopic examination were included in the study. Upon endoscopic examination, the presence of ulceration was noted and biopsy specimens were collected from the gastric antrum, body and transitional zone. Blood was also collected from each patient. Gastric biopsy sections were graded using the Sydney system. H. pylori specific IgG, IgG1, IgG2, IgG3 and IgG4 were measured by ELISA. The IgG subclass was also examined retrospectively in sera collected from 20 patients previously proven to have duodenal ulcer (DU). Results: The results of histological examination and IgG serology showed 35 subjects to be H. pylori negative and 48 to be H. pylori positive. Of the 48 H. pylori positive subjects, 25 were diagnosed with functional dyspepsia (FD), 14 with current DU and 9 with evidence of past DU. Significantly higher levels of IgG2 antibodies were found in patients with DU as compared with patients with FD (P &lt; 0.01). In addition, significantly higher IgG3 subclass antibody levels were associated with chronic inflammatory cells in the body (P &lt; 0.05) and active inflammatory cells in the transitional zone (P &lt; 0.01). A significantly increased level of IgG1 antibodies was associated with lower levels of colonization in the gastric antrum. Conclusion: The results of this study suggest that the IgG subclass response in subjects infected with H. pylori may be a marker of DU disease as well as increased levels of inflammation.