Antibody response to specific H. pylori antigens in functional dyspepsia, duodenal ulcer disease, and health

Serum VacA antibody is associated with risks of peptic ulcer and gastric cancer: A meta-analysis

BACKGROUND

Increasing studies have investigated the relationship between the status of H. pylori vacA antibody and risks of peptic ulcer disease (PUD) and gastric cancer (GC). However, the results were controversial. The aim of this meta-analysis is to clarify whether serum vacA antibody is associated with risks of PUD and GC.

METHODS

Databases including PubMed, Embase, Web of knowledge, Wanfang, Chinese National Knowledge Infrastructure (CNKI), OVID, Karger and Scopus were systematically searched for potentially eligible literature. Odds ratios (OR) and their 95% confidence interval (CI) were adopted to assess the strength of association.

RESULTS

Serum VacA antibody was associated with increased risk of PUD compared with gastritis/functional dyspepsia (FD) (OR = 1.96, 95%CI = 1.56-2.46, P < 0.001). Serum VacA antibody was significantly associated with increased risk of gastric ulcer (GU) and duodenal ulcer (DU) compared with gastritis/FD (GU: OR = 1.64, 95%CI = 1.02-2.62, P = 0.042; DU: OR = 2.06, 95%CI = 1.50-2.84, P < 0.001, respectively). Significant increased risk of GC was found in serum VacA antibody positive subjects compared with serum VacA antibody negative individuals (OR = 2.78, 95%CI = 1.98-3.89, P < 0.001). There was no significant publication bias in all of the comparisons.

CONCLUSIONS

Serum VacA antibody was significantly associated with increased risks of peptic ulcer disease, gastric ulcer and duodenal ulcer compared with gastritis and functional dyspepsia controls. Significant association was also found between serum VacA antibody and gastric cancer risk. Serum VacA antibody might be a potential biomarker for the prediction of risks of PUD and GC.

Correlations between the CagA Antigen and Serum Levels of Anti-Helicobacter pylori IgG and IgA in Children

We tested correlations between anti-Helicobacter pylori IgG and IgA levels and the urease test, anti-CagA protein antibody, degree of gastritis, and age. In total, 509 children (0-15 years) were enrolled. Subjects were stratified as 0-4 years (n = 132), 5-9 years (n = 274), and 10-15 years (n = 103) and subjected to the urease test, histopathology, ELISA, and western blot using whole-cell lysates of H. pylori strain 51. The positivity rate in the urease test (P = 0.003), the degree of chronic gastritis (P = 0.021), and H. pylori infiltration (P < 0.001) increased with age. The median titer for anti-H. pylori IgG was 732.5 IU/mL at 0-4 years, 689.0 IU/mL at 5-9 years, and 966.0 IU/mL at 10-15 years (P < 0.001); the median titer for anti-H. pylori IgA was 61.0 IU/mL at 0-4 years, 63.5 IU/mL at 5-9 years, and 75.0 IU/mL at 10-15 years (P < 0.001). The CagA-positivity rate was 26.5% at 0-4 years, 36.5% at 5-9 years, and 46.6% at 10-15 years for IgG (P = 0.036), and 11.3% at 0-4 years, 18.6% at 5-9 years, and 23.3% at 10-15 years for IgA (P < 0.001). Anti-H. pylori IgG and IgA titers increased with the urease test grade, chronic gastritis degree, active gastritis, and H. pylori infiltration. Presence of CagA-positivity is well correlated with a high urease test grade and high anti-H. pylori IgG/IgA levels.

Functional dyspepsia

PURPOSE OF REVIEW

Structural causes are absent in more than 50% of patients with symptoms referred to the gastroduodenal region when routine diagnostic tests are applied. New knowledge holds the prospect that targeted therapy may more optimally manage subsets of these patients with functional dyspepsia.

RECENT FINDINGS

An understanding of gut-to-brain and brain-to-gut pathways in functional dyspepsia is expanding. Minimal mucosal inflammation with eosinophils (and in some cases mast cells) characterized by ultrastructural changes in the duodenum appears to be present in a substantial subgroup of functional dyspepsia patients as identified now by investigators globally. Although antibiotic therapy targeting Helicobacter pylori appears to be effective in a small proportion of functional dyspepsia patients, eradication therapy may be more effective in functional dyspepsia patients with microscopic duodenal inflammation, a potentially important finding needing to be confirmed. This may suggest that the effects of antibiotics for functional dyspepsia are not simply mediated by the eradication of gastric H. pylori, but have other antibacterial effects (e.g., on the duodenal microbiome). Abnormal visceral sensory function plays a key role not only in the manifestations of functional dyspepsia but also in peptic ulcer disease.

SUMMARY

The pathophysiologic concepts underlying functional dyspepsia and related treatment approaches are shifting from a focus on H. pylori, acid suppression or modulation of motility toward new models. New evidence suggests that minimal duodenal inflammation plays a role in symptom generation in at least a proportion of patients with otherwise unexplained symptoms. This is a paradigm shift and ultimately may change the treatment of many patients with functional gastrointestinal disorders.

Helicobacter Pylori Infection in Children with Type 1 Diabetes Mellitus

Objective: To evaluate H. pylori infection and virulent strain in diabetic children. Patients: In this study 53 type 1 diabetics and 53 of normal volunteers were included. Methods: All studied children were subjected to assessment of glycosylated hemoglobin (HbA1), Anti H. pylori antibodies (IgA, IgG, IgM), Anti-cytotoxin associated gene A antibodies (Anti Cag A IgG). Results: Anti H. pylori antibodies IgA, IgG, total antibodies and anti Cag A IgG were significantly higher in diabetics. Diabetic patients with positive anti Cag A IgG had a lower age of onset of diabetes, higher age of patients, body mass index (BMI) and HbA1. Conclusion: High prevalence of infection with the virulent strain of H. pylori among diabetic children with older age, large BMI, high HbA1 and younger age of onset of disease. The screening for the virulent strain in diabetic patients with poor metabolic control is mandatory. Control of diabetes is essential to present the infection with H. pylori.

Differences between blood donors and a population sample: implications for case-control studies

BACKGROUND

Selecting appropriate controls for studies of genetic variation in case series is important. The two major candidates involve the use of blood donors or a random sample of the population.

METHODS

We compare and contrast the two different populations of controls for studies of genetic variation using data from parents enrolled in the Avon Longitudinal Study of Parents and Children (ALSPAC). In addition we compute different biases using a series of hypothetical assumptions.

RESULTS

The study subjects who had been blood donors differed markedly from the general population in social, health-related, anthropometric, and personality-related variables. Using theoretical examples, we show that blood donors are a poor control group for non-genetic studies of diseases related to environmentally, behaviourally, or socially patterned exposures. However, we show that if blood donors are used as controls in genetic studies, these factors are unlikely to make a major difference in detecting true associations with relatively rare disorders (cumulative incidence through life of <10%). Nevertheless, for more common disorders, the reduction in accuracy resulting from the inclusion in any control population of individuals who have or will develop the disease in question can create a greater bias than can socially patterned factors.

CONCLUSIONS

Information about the medical history of a control and the parents of the control (as a proxy for whether the control will develop the disease) is more important with regard to the choice of controls than whether the controls are a random population sample or blood donors.

cagA, vacA, and iceA genotypes of Helicobacter pylori in Korean children

BACKGROUND

Several putative virulence factors for Helicobacter pylori have been identified including cagA, vacA, and iceA. The aims of the present study were to study the distribution of cagA, vacA, and iceA genotypes in children with H. pylori gastritis and to examine the association of genotypes with severity of gastritis.

METHODS

H. pylori DNA was extracted from antral biopsy specimens from 33 children with H. pylori gastritis. Specific polymerase chain reaction assays were used for three genes: cagA, vacA, and iceA. The features of gastritis were graded in accordance with the updated Sydney System.

RESULTS

Of the 33 children, 31 (94%) were cagA positive. Twenty-four (72%) had s1c genotype and nine (27%) had s1a. The m1 genotype was seen in 27 (82%) and m2 was found in five (15%). The iceA1 genotype was detected in 25 (76%). Scores of neutrophil activity, chronic inflammation, and H. pylori density were independent of cagA, vacA and iceA status.

CONCLUSION

The cagA-positive vacA s1c/m1 iceA1 genotype was predominant in Korean children with recurrent abdominal pain and H. pylori gastritis. The cagA, vacA and iceA genotype were not associated with the severity of gastritis.

Evaluation of the role of H pylori infection in pathogenesis of gastric cancer by immunoblot assay

AIM: To elucidate the different serological reactions to H pylori using the immunoblotting technique for further understanding of its pathogenic role in gastric cancer.

METHODS: A total of 54 patients were divided into two groups after upper gastrointestinal endoscopy: normal control group (25 patients) and gastric cancer group (29 patients). Both groups were further divided into H pylori (+) and H pylori (-) subgroups based on the results of CLO test, Giemsa staining and culture. Sera were further analyzed with the immunoblotting technique (HelicoBlot 2.0, Genelabs Diagnostics, Singapore).

RESULTS: The positive rate of the immunoblotting test was as high as 88.9% in the H pylori (-) gastric cancer group and only 14.3% in the H pylori (-) normal control group with a statistically significant difference.

CONCLUSION: The prevalence of H pylori infection is higher in gastric cancer patients than in the normal controls, suggesting that H pylori may play a role in the pathogenesis of gastric cancer.

Increased seropositivity of Helicobacter pylori cytotoxin-associated gene-A in Behçet's disease

Behçet's disease is a systemic vasculitic syndrome with unknown etiology. The aim of the present study was to compare the Helicobacter pylori seropositivity and cytotoxin associated gene-A status in patients with Behçet's disease. Ninety-one patients with Behçet's disease and 83 age- and sex-matched persons with or without any gastrointestinal complaints were included in the study. Demographic characteristics and H. pylori IgG, IgM, and cytotoxin-associated gene-A IgG status of the Behçet's disease and the control groups were analyzed. The influence of eradication therapy on clinical findings was also determined. The prevalence of H. pylori IgG seropositivity was slightly but not significantly higher in patients with Behçet's disease compared to the controls [72 (79.1%) vs 56 (67.5%), (p = 0.082)]. The prevalence of cytotoxin-associated gene A positivity was significantly higher in Behçet's disease compared to the controls [59 (64.8.%) vs 32 (38.5%), respectively, (p = 0.002)]. Eradication of H. pylori has significantly decreased clinical manifestations such as oral and genital ulceration, arthritis/arthralgia, and cutaneous findings of Bahçet's disease. Our study indicates that H. pylori may be involved in the pathogenesis of Behçet's disease or disease activity might be enhanced due to induced inflammation or altered immunity.

Systematic review and meta-analysis: importance of CagA status for successful eradication of Helicobacter pylori infection

BACKGROUND

Some, but not all studies have provided evidence that the CagA status of Helicobacter pylori strains is a predictive factor for the outcome of eradication therapy.

AIM

To clarify the association between CagA status and eradication outcome.

METHODS

We included studies reporting the numbers of successful and failed cases in H. pylori-eradication therapy according to the CagA status. Fourteen studies (1529 patients) were included of 325 articles identified in the search. The pooled risk ratio for H. pylori-eradication failure in CagA-negative relative to CagA-positive strains and the pooled risk difference in eradication success between the two groups were used as summary statistics. Meta-regression was used for examining the source of heterogeneity.

RESULTS

The summary risk ratio for eradication failure in CagA-negative relative to CagA-positive was 2.0 (95% CI: 1.6-2.4, P < 0.001), corresponding with the summary risk difference for eradication success between the groups of 11% (95% CI: 3-19%, P = 0.011). Meta-regression analysis demonstrated that usage of polymerase chain reaction examination for CagA status and a high proportion of non-ulcer dyspepsia patients were factors for heterogeneity among studies.

CONCLUSIONS

Our meta-analysis confirmed the importance of the presence of CagA as a predictor for successful eradication of H. pylori.

CagA positivity and its association with gastroduodenal disease in Turkish children undergoing endoscopic investigation

BACKGROUND

Cytotoxin-associated gene A (CagA) product is a bacterial virulence factor contributing to the pathogenicity of Helicobacter pylori (HP) infection in humans. Host factors, which vary in different countries, interact with bacterial factors to determine the disease state. Our objective was to investigate the frequency of CagA-positive HP strains and evaluate the contribution of CagA positivity to symptoms and development of mucosal lesions in HP-infected Turkish children.

METHODS

We conducted a prospective clinical trial in 240 consecutive Turkish children undergoing endoscopy (110 girls, 130 boys; mean age, 8.7 +/- 4.3 years). HP infection was diagnosed on the basis of a positive rapid urease test and histology of the mucosal specimens. HP IgG and CagA IgG antibodies were measured by enzyme-linked immunosorbent assay in HP-positive children.

RESULTS

The HP positivity rate was 50.4% in our study group (51 girls, 70 boys; mean age, 9.9 +/- 3.9 years). CagA was positive in 74.4%. HP infection was less common in children with vomiting (25.9%, P < 0.05). CagA positivity was not associated with any clinical symptom. HP positivity was higher in children with duodenal ulcer (80% vs. 49.1%, P = 0.05); while CagA positivity was similar. Antral nodularity was strongly associated with HP positivity and CagA positivity (30.6% vs. 3.4% and 36.7% vs. 12.9%, respectively, P < 0.05). A negative association between CagA positivity and esophagitis was observed (20% vs. 76.7%, P < 0.05).

CONCLUSIONS

CagA positivity is common in HP-infected Turkish children. Esophageal lesions are less common in children infected with CagA-positive strains. Although HP is associated with duodenal ulcer disease, CagA positivity does not seem to contribute to development of ulcers in children in our series.

Hypothesis driven research and molecular mechanisms in functional dyspepsia: the beginning of a beautiful friendship in research and practice?

There is accumulating evidence of a genetic predisposition in at least a subset of patients with functional GI symptoms. Hence, hunting for genes in irritable bowel syndrome and functional dyspepsia has become fashionable of late. Unfortunately, as in other fields, replication of gene association studies has most often been problematic. In this issue of the Journal, independent corroboration of an association of dyspepsia with GNbeta3 is reported. Other carefully selected putative genes including polymorphisms in the alpha2A adrenoreceptor, the serotonin reuptake transporter, and the 5-HT1A receptor were not associated. The study raises three key questions all considered in this editorial: (a) if GNbeta3 is truly associated with functional and uninvestigated dyspepsia, why might this be the case, (b) what molecular mechanisms may be of most relevance, and (c) perhaps most importantly, does or will this finding translate into clinical practice in terms of diagnosis or treatment? New knowledge of gene associations like GNbeta3 and their pathophysiological relevance may ultimately lead to better targeted therapy as well as new disease modifying treatments.

A placebo-controlled trial of itopride in functional dyspepsia

BACKGROUND

The treatment of patients with functional dyspepsia remains unsatisfactory. We assessed the efficacy of itopride, a dopamine D2 antagonist with anti-acetylcholinesterase [corrected] effects, in patients with functional dyspepsia.

METHODS

Patients with functional dyspepsia were randomly assigned to receive either itopride (50, 100, or 200 mg three times daily) or placebo. After eight weeks of treatment, three primary efficacy end points were analyzed: the change from baseline in the severity of symptoms of functional dyspepsia (as assessed by the Leeds Dyspepsia Questionnaire), patients' global assessment of efficacy (the proportion of patients without symptoms or with marked improvement), and the severity of pain or fullness as rated on a five-grade scale.

RESULTS

We randomly assigned 554 patients; 523 had outcome data and could be included in the analyses. After eight weeks, 41 percent of the patients receiving placebo were symptom-free or had marked improvement, as compared with 57 percent, 59 percent, and 64 percent receiving itopride at a dose of 50, 100, or 200 mg three times daily, respectively (P<0.05 for all comparisons between placebo and itopride). Although the symptom score improved significantly in all four groups, an overall analysis revealed that itopride was significantly superior to placebo, with the greatest symptom-score improvement in the 100- and 200-mg groups (-6.24 and -6.27, vs. -4.50 in the placebo group; P=0.05). Analysis of the combined end point of pain and fullness showed that itopride yielded a greater rate of response than placebo (73 percent vs. 63 percent, P=0.04).

CONCLUSIONS

Itopride significantly improves symptoms in patients with functional dyspepsia. (ClinicalTrials.gov number, NCT00272103.).

Enzyme immunoassay and immunoblotting analysis of Helicobacter pylori infection in Turkish asymptomatic subjects

Approximately half of the world population is infected with Helicobacter pylori, particularly in developing countries. The aims of the study were to detect H. pylori infection in asymptomatic Turkish subjects, correlate the infection with the associated risk factors, and to evaluate the cytotoxin-associated gene (CagA) status and other H. pylori antigens. Three hundred nine asymptomatic subjects (124 female) 1-82 years of age (average: 31 years) were serologically tested by enzyme immunoassay and immunoblotting. The enzyme immunoassay detected IgG anti-H. pylori antibodies in sera of 216 (70%) out of 309 subjects, 132 (61%) male. Infection rates of 42% in subjects <10 years of age, 55% in 10-19 years, 66% in 20-29 years, 78% in 30-39 years, 79% in 40-49 years, 91% in 50-59 years, 100% in 60-69 years, and 80% in those >70 years of age were detected. Subjects >45 years of age had significantly higher antibody responses, odds ratio = 0.16 (95% confidence interval: 0.07-0.37), than those <45 years. H. pylori infection was significantly higher in married subjects, odds ratio = 0.38 (95% confidence interval: 0.20-0.73), and those with low socioeconomic status. No correlation between gender, education, smoking, and nonsteroidal anti-inflammatory drug intake and infection was detected. Immunoblots revealed antibodies to CagA in 58 (83%) of 70 samples tested. H. pylori infection is prevalent in the asymptomatic Turkish subjects. Marital and socioeconomic status was significantly associated with the acquisition of H. pylori. Antibodies to CagA antigen were highly prevalent in these subjects.

Molecular basis of functional gastrointestinal disorders

There are a number of abnormalities of gastrointestinal function, including sensory and motor dysfunction, which are believed to play a role in the manifestation of symptoms in patients with functional gastrointestinal disorders (FGID). In addition, there is a remarkable psychiatric comorbidity. Family and twin studies have provided strong evidence for a clustering of FGID in families and an increased concordance in monozygotic compared to dizygotic twins. This points towards the role of one or more hereditary (genetic) factors. Considering these disorders of function and the psychiatric comorbidity, polymorphisms of adrenergic, opioidergic or serotonergic receptors as well as G-protein beta3 (GNB3) subunit gene polymorphisms (C825T) and polymorphisms of 5-HT transporter genes are suitable causes. In addition, mediators or regulators of mucosal inflammation may trigger events that ultimately result in the manifestation of FGID. Thus, relevant polymorphisms of genes with immunmodulating and/or neuromodulating features (OPRM1, IL-4, IL-4R, TNFalpha) may also play a role in the manifestation of FGIDs.

Immunoblotting for the serodiagnosis of Helicobacter pylori infection in Brazilian patients with and without gastric carcinoma

We evaluated the performance of a commercial immunoblotting in the serodiagnosis of Helicobacter pylori infection in Brazilian patients. The presence of anti-H. pylori antibodies was also investigated in a group of 20 duodenal ulcer patients after successful treatment. One hundred and ninety one patients were studied. Among the 164 infected patients, 46 had gastric carcinoma. The duodenal ulcer patients were treated with antimicrobial drugs and the eradication of the microorganism was confirmed in all of them one month after the end of the treatment by the 13C-urea breath test. Sera were assayed for H. pylori antibodies using the Helicoblot 2.0 (Genelabs Diagnostics, Singapore). The sensitivity, specificity, positive, and negative predictive values of the test were 93.9%, 92.6%, 98.7%, and 71.4%, respectively. The sensitivity of the test was similar in patients with (93.5%) and without (95.7%) gastric carcinoma. Twenty-four months after the end of the treatment, the band of 116 kDa was still detected in one of the patients. In conclusion, the Helicoblot 2.0 is an accurate test to diagnose H. pylori infection and although it can not be employed to monitor the bacterium eradication, it may be useful for diagnosing past infection, especially in gastric carcinoma patients.

Dyspeptic symptoms associated with Helicobacter pylori infection are influenced by strain and host specific factors

BACKGROUND

Dyspepsia can be associated with H. pylori infection.

AIM

To assess dyspeptic symptoms and potentially influencing factors before and up to 6 months following successful H. pylori eradication therapy.

METHODS

Prospective cohort study involving H. pylori positive subjects from ambulatory or hospitalized care. Main outcome measures were symptoms during baseline and follow-up, the proportion of symptom-free patients, and symptom scores.

RESULTS

After successful eradication, the summary score of all dyspeptic symptoms decreased and during follow-up, the proportion of symptom-free patients was higher in the group with peptic ulcers (69.4% vs. 40.9%, P < 0.0001) than with functional dyspepsia (FD). Regardless of diagnosis, virulent strains of H. pylori were associated with a higher prevalence of epigastric pain before treatment: absolute risk-difference (ARD) with Oip-A: 18.2%, Odds Ratio (OR) 2.35 [1.3-4.2, 95%-CI], P = 0.01; with Cag-A: 24.6%, OR 2.81 [1.6-5], P = 0.01. Low-dose aspirin in part was a major risk factor in FD for previous weight loss bdfore study entry. Post-treatment, non-ulcer patients were more likely to suffer from distention/bloating. Likewise, alcohol induced persistence of nausea and vomiting in this population.

CONCLUSIONS

Dyspeptic symptoms in H. pylori infected patients are more common with virulent strains. Symptoms are more likely to persist despite successful eradication if patients initially harboured virulent strains or concomitant aspirin or alcohol intake are present. In one-third of peptic ulcer patients, symptoms will not be cured 3 months after therapy.

IBS: a syndrome or many diseases?

Patients with irritable bowel syndrome (IBS) are characterized by a broad spectrum of gastrointestinal (GI) symptoms. These IBS-symptoms and symptoms of other functional GI disorders frequently overlap. Moreover, at least in patients with severe disease manifestations there is a remarkable psychiatric comorbidity. There is a number of abnormalities of GI functions including sensory and motor dysfunction that are believed to play a role for the manifestation of symptoms in patients with these functional gastrointestinal disorders (FGID). Family studies provide strong evidence for a clustering of FGID in families. Furthermore, twin studies clearly demonstrate an increased concordance in monocygotic compared to dicygotic twins. This points towards the role of one or more hereditary factors. Considering sensory and motor function as well as the psychiatric comorbidity, polymorphisms of adrenergic, opioidergic or serotonergic receptors as well as G-protein beta3 (GNB3) subunit gene polymorphism and polymorphisms of 5-HT transporter genes are suitable mechanisms for these abnormalities. Hence acute GI infections with a mucosal inflammation appear to trigger a cascade of events that ultimately results in the manifestation of FGID, it is reasonable to assume that functionally relevant polymorphisms of genes with immunmodulating and/or neuromodulating features (OPRM1, IL-4, IL-4R, TNFalpha) play a role. It has emerged that a number of various factors may contribute to the manifestation of functional GI disorders. The currently symptom based labels for functional GI disorders may be helpful to categorize patients and target therapy. However, various underlying pathophysiologies may cause similar symptom patterns. Thus, it is reasonable to anticipate that IBS will be dissected accordingly and our disease concepts will accept the irritable bowel syndrome as the clinical manifestation of a number of different disorders.

Unexpected decrease with age of Helicobacter pylori seroprevalence among Swedish blood donors

Blood donors are often used as proxies for the general population in studies of Helicobacter pylori epidemiology. Our aim was to test if the age-specific seroprevalence rates among blood donors match with the corresponding rates in a random population sample. This descriptive study was based on sera obtained from 3,502 blood donors representing all Swedish counties and cities. An age-stratified random population sample of 1,030 from Stockholm County served as comparison. Sera were analyzed by an in-house enzyme-linked immunosorbent assay for H. pylori immunoglobulin G antibodies. In the population sample, we found the expected increase with age in the seroprevalence of H. pylori infection. This was true also among young blood donors, while the prevalence-by-age curve showed a deflection downward among blood donors who are >/= 50 years of age. In this age group, the probability of being seropositive was reduced by 73% (95% confidence interval [CI], 63 to 81%) relative to the population sample. Overall, the adjusted odds ratio for H. pylori seropositivity among blood donors was decreased by 43% (95% CI, 28 to 55%). Thus, it appears that blood donors who are H. pylori seropositive selectively disappear from the blood donor cohort. We speculate that H. pylori-seropositive blood donors may tolerate repeated bleedings less well than do noninfected individuals and/or that the general well-being among those who are infected may be somewhat impaired. Our unexpected observation indicates that blood donors may be less suitable as proxies for the general population in analytic studies of H. pylori infection and that the underlying cause needs further study.

Association of CagA and VacA presence with ulcer and non-ulcer dyspepsia in a Turkish population

AIM: The mostly known genotypic virulence features, of H. pylori are cytotoxin associated gene A (CagA) and Vacuolating cytotoxin gene A (VacA). We investigated the association of these major virulence factors with ulcer and non-ulcer dyspepsia in our region.

METHODS: One hundred and forty two dyspeptic patients were studied (average age 44.8 ± 15.9 years, range 15-87 years, 64 males and 78 females). Antral and corpus biopsies were taken for detecting and genotyping of H. pylori. 107 patients who were H. pylori positive by histological assessment were divided into three groups according to endoscopic findings: Duodenal ulcer (DU), gastric ulcer (GU) and non-ulcer dyspepsia (NUD). The polymerase chain reaction (PCR) was used to detect CagA and VacA genes of H. pylori using specific primers.

RESULTS: H. pylori was isolated from 75.4% (107/142) of the patients. Of the 107 patients, 66 (61.7%) were CagA-positive and 82 (76.6%) were VacA-positive. CagA gene was positively associated with DU and GU (P < 0.01, P < 0.02), but not with NUD (P > 0.05). Although VacA positivity in ulcer patients was higher than that in NUD group, the difference was not statistically significant (P > 0.05).

CONCLUSION: There is a significantly positive association between CagA genes and DU and GU. The presence of VacA is not a predictive marker for DU, GU, and NUD in our patients.

Clinical and pathological implications of IgG antibody responses to Helicobacter pylori and its virulence factors in non-ulcer dyspepsia

AIM

To determine whether pre-treatment antibody response to Helicobacter pylori virulence factors predicts eradication success and symptom relief 12 months after triple therapy in non-ulcer dyspepsia.

METHODS

H. pylori-positive patients with non-ulcer dyspepsia received 1-week omeprazole-based triple therapy, or omeprazole plus placebos. Symptoms were assessed using a validated Likert scale. Gastric biopsies taken before and 12 months after treatment were used for histological examination. Pre-treatment blood samples were used for the detection of anti-H. pylori immunoglobulin G (IgG) antibodies, and specific IgG antibodies to 19.5-, 26.5-, 30-, 35-, 89- (VacA) and 116-kDa (CagA) antigens of H. pylori.

RESULTS

IgG antibodies to the six antigens were detected in 62%, 96%, 88%, 47%, 54% and 78% of patients, respectively. The presence of antibody to 19.5-, 26.5- or 30-kDa antigen was associated with an increased anti-H. pylori IgG absorbance index. IgG absorbance indices were greater in those with H. pylori eradication (vs. persistent infection). The prevalence of antibodies to the six antigens was not significantly different between those with symptom relief vs. those without. The 19.5-kDa antigen (P = 0.018) and VacA (P = 0.001) were independent risk factors for body gastritis.

CONCLUSIONS

An increased pre-treatment anti-H. pylori IgG absorbance index may be a useful predictor of the success of eradication therapy. Although the 19.5-kDa antigen and VacA were associated with body gastritis, none of the six antigens tested predicted symptom relief after triple therapy.

Prevalence of Helicobacter pylori infection in asymptomatic subjects in Libya

Helicobacter pylori infection is very common infection worldwide particularly in the developing countries. No detailed study on such infection is being recorded so far in Libya. The aims of the study were to detect H. pylori prevalence in asymptomatic Libyan subjects, to determine the rate of infection among different age groups and to correlate the prevalence of H. pylori with age, sex, smoking, non-steroidal anti-inflammatory drugs intake, marital status, education, and socioeconomic status. Three hundred and sixty asymptomatic subjects 1->70 years of age (average 36) with no previous history of epigastric pain were selected randomly from the Libyan population. Serum samples were obtained and a questionnaire was filled for each subject. The ELISA test was used to detect IgG anti-H. pylori antibodies. An overall prevalence of 76% was detected in these subjects. A 50% infection rate were in subjects 1-9 years of age that increased to 84% in subjects 10-19 years and continued with increasing age and reached up to 94% in those over 70 years of age. Subjects > 45 years of age had significantly higher antibody response than those <45 years. H. pylori prevalence was higher in married subjects (84%) as compared to singles (68%) and similarly in illiterates (89%) and low socioeconomic subjects (91%). No difference in sex, smoking and NSAIDs intake was recorded. Infection with H. pylori is highly prevalent in the Libyan asymptomatic subjects. Infection acquired early in childhood and reached up to 94% in older age. Prevalence of H. pylori was significantly increased in association with marital status, education and low socioeconomic status.

Helicobacter pylori infection, anti-cagA antibodies and peptic ulcer: a case-control study in Italy

AIM

To evaluate the association between infection with specific strains of Helicobacter pylori and peptic ulcer in patients referred for upper gastrointestinal endoscopy.

METHODS

One thousand, six hundred and twenty-six consecutive dyspeptic patients, referred to one Endoscopy Unit in Bologna, Italy, were enrolled. For each participant, a blood sample was obtained for the measurement of distinct immunoglobulin G antibodies against H. pylori lysate and cytotoxin associated gene A (cagA). A case-control study included the whole series: patients diagnosed with duodenal (n=275) or gastric (n=71) ulcer were identified and independently compared with controls with non-ulcer dyspepsia (n=1280).

RESULTS

H. pylori seroprevalence (at least one positive marker) was associated with increasing age, male sex and a diagnosis of peptic ulcer. This association was stronger with duodenal ulcer (multivariate odds ratio (OR), 5.2; 95% confidence interval (CI), 3.5-7.9) than with gastric ulcer (OR, 2.3; 95% CI, 1.2-4.4). Further analyses showed that H. pylori lysate+/cagA- subjects had a moderately increased risk of duodenal (OR, 3.2), but not gastric (OR, 1.1), ulcer. When cagA+ subjects were separately compared with seronegative patients, there was a six-fold increased risk for duodenal ulcer and a three-fold increased risk for gastric ulcer.

CONCLUSIONS

A strong positive association between infection with a cagA+ H. pylori strain and the presence of peptic disease was found. The seroprevalence of anti-cagA antibodies among patients with non-ulcer dyspepsia is so high (41%) to preclude its use as a pre-endoscopic screening test.

Review article: Helicobacter pylori and nonulcer dyspepsia

Although up to 50% of patients diagnosed with nonulcer dyspepsia (NUD) have Helicobacter pylori infection and underlying chronic gastritis, it remains controversial whether any causal relationship exists. The results of worldwide epidemiological studies have been unconvincing. No clear-cut link has been documented between H. pylori and any specific symptom profile or pathophysiological mechanism in NUD. In the randomized controlled trials, methodological weaknesses may explain in part the conflicting results, but even in the well-conducted trials controversy persists. Although meta-analyses have attempted to resolve the issue, inherent methodological difficulties with meta-analysis remain a problem. Moreover, even the methodologically sound meta-analyses have reported conflicting results. In addition, predictors of treatment response remain obscure, and there continue to be theoretical concerns about the treatment of H. pylori infection in all patients with NUD. Hence, the management of these patients is challenging, but eradication of H. pylori infection may be beneficial in a small subgroup of cases with NUD that cannot be identified before treatment.

Ischaemic heart disease and Cag A strains of Helicobacter pylori in the Caerphilly heart disease study

OBJECTIVE

To look for the presence of the more virulent strains of Helicobacter pylori (H pylori) in men who developed ischaemic heart disease over a 10 year period and in controls.

DESIGN

The Caerphilly prospective heart disease study recruited 2512 men aged 45-59 years during 1979-83. Western blot analysis or enzyme linked immunosorbent assay (ELISA) was performed on serum taken from those who subsequently died of ischaemic heart disease, or developed non-fatal myocardial infarction, to determine H pylori and Cag A status. Similar information was available on age matched controls.

RESULTS

During the first decade of the study, 312 men died of ischaemic heart disease or developed non-fatal myocardial infarction. Serum was available from 172 of these (55%). There was no evidence of an association between Cag A seropositivity and incident ischaemic heart disease or ischaemic heart disease mortality, either before or after adjustment for potential confounders (adjusted odds ratios 1.18 (95% confidence interval (CI) 0.76 to 1.85) and 1.13 (95% CI 0.61 to 2.07), respectively). Further, the odds ratios for ischaemic heart disease incidence and ischaemic heart disease mortality by H pylori seropositivity did not appear to depend on the presence or absence of Cag A strains (p = 0.76 and 0.77, respectively).

CONCLUSIONS

In this cohort of middle aged men, followed over a 10 year period, there is little evidence of an association between Cag A seropositivity and either incident ischaemic heart disease or ischaemic heart disease mortality.

Nonulcer dyspepsia

Nonulcer dyspepsia, characterized by unexplained persistent or recurrent epigastric pain or discomfort, affects approximately 20% of the general population. Symptom-based diagnostic criteria, first developed by an international group of experts, have been refined in the past year in an effort to increase the applicability of the criteria (Rome II criteria). New disease-specific questionnaires that were developed to measure quality of life in patients with dyspepsia are now available and are expected to be widely used in clinical research studies. Studies on the pathophysiology and management of nonulcer dyspepsia were other major topics in the past year, including three large, well-conducted randomized controlled trials of Helicobacter pylori eradication and symptom resolution.