Positive serum antibody and negative tissue staining for Helicobacter pylori in subjects with atrophic body gastritis

Prevalence of Helicobacter pylori infection in advanced gastric carcinoma

BACKGROUND

[corrected] There is substantial evidence that infection with Helicobacter pylori plays a role in the development of gastric cancer and that it is rarely found in gastric biopsy of atrophic gastritis and gastric cancer. On advanced gastric tumors, the bacteria can be lost from the stomach.

AIMS

To analyze the hypothesis that the prevalence of H.pylori in operated advanced gastric carcinomas and adjacent non-tumor tissues is high, comparing intestinal and diffuse tumors according to Lauren's classification

METHODS

A prospective controlled study enrolled 56 patients from "Hospital Universitário", Federal University of Rio Grande do Norte, Natal, RN, Brazil, with advanced gastric cancer, treated from February 2000 to March 2003. Immediately after partial gastrectomy, the resected stomach was opened and several mucosal biopsy samples were taken from the gastric tumor and from the adjacent mucosa within 4 cm distance from the tumor margin. Tissue sections were stained with hematoxylin and eosin. Lauren's classification for gastric cancer was used, to analyse the prevalence of H. pylori in intestinal or diffuse carcinomas assessed by the urease rapid test, IgG by ELISA and Giemsa staining. H. pylori infected patients were treated with omeprazole, clarithromycin and amoxicillin for 7 days. Follow-up endoscopy and serology were performed 6 months after treatment to determine successful eradication of H. pylori in non-tumor tissue. Thereafter, follow-up endoscopies were scheduled annually. Chi-square and MacNemar tests with 0.05 significance were used.

RESULTS

Thirty-four tumors (60.7%) were intestinal-type and 22 (39.3%) diffuse type carcinomas. In adjacent non-tumor gastric mucosa, chronic gastritis were found in 53 cases (94.6%) and atrophic mucosa in 36 patients (64.3%). All the patients with atrophic mucosa were H. pylori positive. When examined by Giemsa and urease test, H. pylori positive rate in tumor tissue of intestinal type carcinomas was higher than that in diffuse carcinomas. In tumor tissues, 34 (60.7%) H. pylori-positive in gastric carcinomas were detected by Giemsa method. H. pylori was observed in 30 of 56 cases (53.5%) in tissues 4 cm adjacent to tumors. This difference was not significant. Eradication of H. pylori in non-tumor tissue of gastric remnant led to a complete negativity on the 12th postoperative month

CONCLUSIONS

The data confirmed the hypothesis of a high prevalence of H. pylori in tumor tissue of gastric advanced carcinomas and in adjacent non-tumor mucosa of operated stomachs. The presence of H. pylori was predominant in the intestinal-type carcinoma.

How labile is gastric infection with H pylori?

It is known that patients infected with H pylori can spontaneously become free from infection, and that the reverse change can occur. The time-scale of these conversions is expressed as percentages per year. Since they have been investigated in terms of serology, the changes are called sero-reversion and sero-conversion respectively. Using serological evidence to investigate these phenomena is open to the criticisms that positive serology can be present in the absence of all other evidence of infection, and that a time-lag of 6-12 mo or longer can occur between eradication of the infection and sero-reversion. Investigations using direct evidence of current infection are sparse. The few that exist suggest that some individuals can seroconvert or sero-revert within six to twelve weeks. If these findings are confirmed, it means that some patients have an ability that is variable in time to resist, or spontaneously recover from, H pylori infection. Evidence suggests that the deciding factor of susceptibility is the level of gastric secretion of acid.

The association between Helicobacter pylori infection and early gastric cancer: a meta-analysis

OBJECTIVE

Helicobacter pylori (H. pylori) is recognized as a definite carcinogen for gastric cancer. The prevalence of H. pylori infection in patients with gastric cancer varies widely among studies and no meta-analysis on the prevalence of H. pylori infection in early gastric cancer (EGC) has been performed. We aimed to review systematically the relationship between H. pylori infection and EGC, and different types of EGC.

METHODS

Observational studies reporting raw data on the prevalence of H. pylori infection in EGC and controls, or comparing different types of EGC, conducted in adult populations, and published in the English language were identified through MEDLINE and EMBASE up to June 2006.

RESULTS

Of 87 relevant studies, 19 case-control studies met inclusion criteria. Of these, 15 studies compared EGC (N = 2,722) and non-neoplasm controls (N = 13,976) or advanced gastric cancer (AGC) (N = 1,130), 9 studies compared the intestinal-type (I-EGC) and diffuse-type (D-EGC) of EGC, and 2 studies compared the differentiated-type (DF-EGC) and undifferentiated-type (UDF-EGC) of EGC and were included in the meta-analysis. The prevalence of H. pylori infection was significantly higher in patients with EGC (87.3%) than in non-neoplasm controls (61.4%) (OR 3.38, 95% CI 2.15-5.33, P < 0.00001). However, significant heterogeneity was seen (P < 0.00001). Four large sample (N > or = 100) studies (N = 2,060) may result in the heterogeneity, but the conclusion remained unchanged when sensitivity analysis was made with the other 11 homogeneous small sample studies alone, in which the prevalence of H. pylori infection was significantly higher in EGC (N = 662) than that in controls (N = 5,898) (87.8%vs 68.6%, P < 0.00001), and the odds ratio (OR 3.28, 95% CI 2.34-4.61) was similar to the large sample studies alone (OR 3.40, 95% CI 1.14-10.12). The prevalence of H. pylori infection in EGC was significantly higher than in AGC (6 studies) (OR 2.13, 95% CI 1.75-2.59) and 16-fold higher in patients with DF-EGC than in those with UDF-EGC (OR 16.53, 95% CI 2.64-103.43). No significant difference in the prevalence of H. pylori infection was seen between the patients with I-EGC and D-EGC types (OR 0.75, 95% CI 0.26-2.18).

CONCLUSIONS

This study indicates that H. pylori infection is strongly associated with early gastric cancer when compared with non-neoplasm controls or advanced gastric cancer. To determine more accurately the effect size of H. pylori in EGC, age-matched normal controls or adjusting for age in the analysis should be considered in H. pylori-related gastric cancer case-control studies.

Infection à Helicobacter pylori chez la personne âgée

PURPOSES

Helicobacter pylori (H. pylori) infection is a chronic gastric Gram-negative infection that increases with age. Acquired in childhood, H. pylori infection may induce a whole cascade of events leading to gastric pathologies such as peptic ulcer diseases, gastric precancerous lesions, and gastric lymphomas (MALT). The characteristics of the diagnosis and the treatment of this infection in geriatrics are thus particularly important to take into account.

MAIN POINTS

1) The incidence of gastric and duodenal ulcers and their bleeding complications is increasing in old-aged populations. Clinical signs such as anorexia and malnutrition are proven to be excellent indications for endoscopic explorations in the elderly. NSAID-use and H. pylori infection were shown to be independent and unrelated risk factors for peptic ulcer and gastroduodenal bleeding in elderly subjects; 2) H. pylori infection diagnosis is difficult to realize in the very old population, and the urea breath test is the test which obtain the best performances in this population.

PERSPECTIVES

Recent work showed the part played by H. pylori chronic infection in gastric aging and in appetite regulation in the elderly. Research tasks should be continued in this field in order to better understand the part played by this chronic infection in gastric aging and in other pathologies (i.e. neurological or cardiovascular diseases) in this population.

Helicobacter pylori detection and antimicrobial susceptibility testing

The discovery of Helicobacter pylori in 1982 was the starting point of a revolution concerning the concepts and management of gastroduodenal diseases. It is now well accepted that the most common stomach disease, peptic ulcer disease, is an infectious disease, and all consensus conferences agree that the causative agent, H. pylori, must be treated with antibiotics. Furthermore, the concept emerged that this bacterium could be the trigger of various malignant diseases of the stomach, and it is now a model for chronic bacterial infections causing cancer. Most of the many different techniques involved in diagnosis of H. pylori infection are performed in clinical microbiology laboratories. The aim of this article is to review the current status of these methods and their application, highlighting the important progress which has been made in the past decade. Both invasive and noninvasive techniques will be reviewed.

CagA and VacA are immunoblot markers of past Helicobacter pylori infection in atrophic body gastritis

BACKGROUND AND AIM

Atrophic body gastritis (ABG) may be induced by H. pylori infection. It is difficult to diagnose H. pylori infection in this condition, since during progression of body atrophy the bacterium disappears. In 30% of patients with ABG no sign of H. pylori infection is detectable. We aimed to investigate whether patients with ABG, classified as H. pylori-negative by conventional methods (ELISA serology and Giemsa stain histology), have been previously exposed to the infection.

METHODS

Case series consisted of 138 outpatients with ABG, of whom 31 are H. pylori negative (histology and ELISA serology), and 107 are H. pylori related (histology and ELISA serology positive: active infection, n = 29; only serology positive: past infection, n = 78). Thirty control subjects who were H. pylori negative at histology and ELISA serology were investigated. Immunoblotting of sera against H. pylori whole-cell protein lysate was performed.

RESULTS

None of the control sera recognized CagA, VacA, heat-shock protein B, and urease B, yielding a specificity of 100%. All H. pylori-negative patients with ABG showed immunoblotting seroreactivity, including in each case either CagA or VacA. The concomitant seroreactivity against CagA and VacA was highly prevalent in the H. pylori-negative patients with ABG, comparable to those with active infection (77.4% vs. 86.2%) and with past infection (vs. 61.5%).

CONCLUSIONS

Immunoblotting against CagA and VacA is able to prove past exposure to H. pylori infection in all patients with ABG defined as H. pylori-negative by conventional methods, suggesting a hidden role of H. pylori infection in gastric atrophy also in these patients.

Progression of atrophic gastritis and intestinal metaplasia drives Helicobacter pylori out of the gastric mucosa

This study was performed to evaluate the implication of anti-H. pylori IgG positivity when CLOtest, histological test, and culture in the antrum and body are all negative, and to find out the specific disease category that is more affected by the hostile relationship of atrophic gastritis and intestinal metaplasia (IM) with H. pylori. Four hundred thirty-six patients (84 controls, 69 with duodenal ulcer, 96 with benign gastric ulcer, 43 with dysplasia, 144 with gastric cancer), who had not received any eradication therapy, were divided into three groups according to H. pylori test: CLOtest or histological H. pylori-positive group (group A; 294 cases), only anti-H. pylori IgG-positive group (group B; 62 cases), and anti-H. pylori IgG-negative group (group C; 80 cases). The grade of neutrophil and monocyte infiltration, atrophic gastritis, and IM was compared according to the updated Sydney system classification. Neutrophil and monocyte infiltrations were significantly severe in the group A. In contrast, the grade of atrophic gastritis and IM in the antrum was significantly higher in group B than the other two groups, A or C. When patients were divided according to the disease outcome in each group, the grade of IM in the body was statistically higher only in the patients with cancer or dysplasia in group B. These results suggest that anti-H. pylori IgG positivity with all negative invasive H. pylori tests represents past infection with H. pylori rather than a false negative, especially in the case of dysplasia and gastric cancer.

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.

Effect of Helicobacter pylori infection combined with CagA and pepsinogen status on gastric cancer development among Japanese men and women: a nested case-control study

BACKGROUND

Although accumulating evidence suggests that Helicobacter pylori plays a role in gastric carcinogenesis, the magnitude of the risk remains uncertain.

AIM

We aimed to estimate the magnitude of the risk of gastric cancer associated with H. pylori infection by a large case-control study nested within a prospective cohort. Possible effect modification by CagA status, and serum pepsinogen status, as a marker of atrophic gastritis, was also considered to see its effect on developing gastric cancer.

SUBJECTS AND METHODS

Subjects (n = 123,576) were followed up from 1990 to 2004; 511 gastric cancer cases matched to 511 controls were used in the analysis. Plasma immunoglobulin G antibody to H. pylori, CagA, and pepsinogen I and II were measured.

RESULTS

The adjusted odds ratio (95% confidence interval) of gastric cancer associated with H. pylori infection was 5.1 (3.2-8.0). Assuming all CagA-positive subjects are true H. pylori positives doubled this risk. Atrophic gastritis was also associated with an elevated risk of gastric cancer and the risk increased further with pepsinogen levels.

CONCLUSIONS

Subjects with pepsinogen levels indicative of severe atrophic gastritis may need careful examination regularly regardless of H. pylori infection. Those who have other pepsinogen levels but who are H. pylori seropositive are likely to benefit from H. pylori eradication therapy. Considering both the cost and the potential for misclassification that may occur using multiple serologic tests, caution is needed in interpreting or extrapolating these findings into a screening strategy.

Opposing Risks of Gastric Cardia and Noncardia Gastric Adenocarcinomas Associated With Helicobacter pylori Seropositivity

BACKGROUND

Colonization with Helicobacter pylori is a risk factor for gastric adenocarcinoma, but the magnitude of this association and its relationship to anatomic location of the cancer, duration of follow-up, age at diagnosis, histologic subtype, and H. pylori strain differences are less clear. We conducted a prospective nested case-control study of H. pylori serology to address these questions.

METHODS

Case and control subjects were selected from the 29,133 50- to 69-year-old males recruited into the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study. At baseline, detailed demographic data and a serum sample were collected. From 1985 to 1999, 243 incident cases of gastric adenocarcinoma were diagnosed in cohort members. Serum samples from 234 case subjects (173 with noncardia gastric cancers and 61 with gastric cardia cancers) and 234 age-matched control subjects were assayed for antibodies against H. pylori whole-cell and CagA antigens. We fit conditional logistic regression models to estimate the unadjusted and adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for the association of H. pylori seropositivity, defined as seropositivity to either whole-cell or CagA antigens, with noncardia gastric and gastric cardia cancers. All statistical tests were two-sided.

RESULTS

H. pylori seropositivity was strongly associated with the risk of noncardia gastric cancer (adjusted OR = 7.9, 95% CI = 3.0 to 20.9) but was inversely associated with the risk of gastric cardia cancer (adjusted OR = 0.31, 95% CI = 0.11 to 0.89). H. pylori seropositivity rates did not vary statistically significantly by length of follow-up, age at diagnosis, or histologic subtype. A calculation of rates showed that the absolute risks of noncardia gastric and cardia gastric adenocarcinomas in the H. pylori-positive participants of this cohort would be 63 and 12 per 100,000 person-years, respectively, whereas corresponding rates in H. pylori-negative participants would be 8 and 37 per 100,000 person-years, respectively.

CONCLUSION

H. pylori is a strong risk factor for noncardia gastric cancer but is inversely associated with the risk of gastric cardia cancer. These findings bolster the hypothesis that decreasing H. pylori prevalence during the past century may have contributed to lower rates of noncardia cancer and higher rates of cardia cancer in Western countries.

Pathology of the gastroesophageal junction

The gastroesophageal junction (GEJ) is a poorly defined anatomic area that represents the junction etween the distal esophagus and the proximal stomach (cardia). The true anatomic GEJ corresponds to the most proximal aspect of the gastric folds, which represents an endoscopically apparent transition oint in most individuals. Many, if not most, adults, particularly those with either physiologic or logic GERD, have a proximally displaced Z-line indicating that the histologic squamocolumnar nction (SCJ) is located above the anatomic GEJ. The histologic characteristics of short segments of columnar mucosa located above the anatomic GEJ in these individuals are similar to the gastric cardia, ng composed of either pure mucous glands or mixed mucous glands/oxyntic glands. Although controversial, some authors believe that the cardia is normally composed, at birth, of surface mucinous columnar epithelium and underlying oxyntic glands identical to the gastric corpus, whereas others maintain that the true anatomic cardia is normally composed of mucinous columnar epithelium with underlying mucous glands or mixed mucous and oxyntic glands. However, the preponderance of evidence supports the latter theory and that the length of mucosa composed of either mucous, or mixed mucous glands/oxyntic glands, increases with age and is presumed to be related to ongoing GERD. Inflammation of the true gastric cardia (carditis), which is most often due to H. pylori infection, is difficult to distinguish from columnar metaplasia of the distal esophagus secondary to GERD. From a pathologist's perspective, the differential diagnosis of true gastric carditis from esophageal columnar metaplasia of the distal esophagus in GEJ biopsies is difficult, but a variety of clinical, pathologic, and immunohistochemical methods can be used to help separate these two disorders. Nearly one-third of patients who present for upper GI endoscopy without endoscopic evidence of BE reveal foci of intestinal metaplasia in the GEJ. There are some studies to suggest that the risk of dysplasia and cancer is different in patients with intestinal metaplasia in the cardia related to H. pylori infection versus those with metaplastic columnar epithelium in the distal esophagus related to GERD. Chronic inflammation is generally considered the predominant underlying stimulus for the development of columnar metaplasia in the GEJ, regardless of the etiology. Columnar metaplasia and intestinal metaplasia in the distal esophagus represents a squamous to columnar cell transition and there is some evidence that this occurs through an intermediate, or transitional, phase of intestinalization termed multilayered epithelium. In contrast, intestinal metaplasia that develops in the true gastric cardia secondary to H. pylori infection represents a columnar to columnar metaplastic reaction. This review will focus on the clinical, pathologic, and pathogenetic aspects of GERD and H. pylori-induced inflammation of the GEJ region.

CD25+/Foxp3+ T cells regulate gastric inflammation and Helicobacter pylori colonization in vivo

BACKGROUND & AIMS

Helicobacter pylori infects more than half of the world's population. In contrast to most other pathogens, the microbe persists for the virtual life of its host. It is unclear why the immune system is unable to eliminate the infection, but recent studies suggested that CD4+/CD25+/Foxp3+ regulatory T cells may be involved in this process.

METHODS

By using a mouse model of infection and gastric biopsies from 108 patients, we performed a detailed descriptive and functional characterization of the Helicobacter-induced CD25+/Foxp3+ T-cell response.

RESULTS

In C57BL/6 mice, H pylori induced a marked gastric Foxp3+ T-cell response, which increased over several months together with the severity of inflammation, until a stable homeostatic situation became established. Accordingly, in Helicobacter-infected patients, but not in uninfected individuals, large numbers of gastric Foxp3+ T cells were detected immunohistochemically. To define the functional in vivo relevance of this response, CD25+ cells were depleted systemically in mice by using an anti-CD25 monoclonal antibody (PC61). Already 4 weeks after infection, PC61-treated mice, but not untreated animals, developed a severe gastritis with heightened cytokine expression and increased numbers of mucosal T cells, B cells, and macrophages. This was accompanied by increased titers of H pylori-specific IgG1 and IgG2c antibodies in the sera of PC61-treated mice. This increased gastric inflammatory response in CD25-depleted mice was associated with reduced bacterial loads.

CONCLUSIONS

CD25+/Foxp3+ T cells actively participate in the immune response to H pylori. In vivo depletion of these cells in infected mice leads to increased gastric inflammation and reduced bacterial colonization.

Helicobacter pylori eradication in the healing of atrophic gastritis: a one-year prospective study

OBJECTIVE

Whether gastric atrophy or intestinal metaplasia heals after successful treatment of Helicobacter pylori (H. pylori) infection is still a matter of controversy. The aim of this article was to clarify whether, after one year, H. pylori eradication is associated with healing in glandular atrophy and intestinal metaplasia in the corpus and antrum.

MATERIAL AND METHODS

Ninety-two H. pylori-positive peptic ulcer patients with atrophic gastritis (panatrophy, antral or corpus predominant) participated in the baseline study, 1-year prospective follow-up data being available from 76 patients. Mean age was 58+/-12.6 years (mean+/-SD) and the male/female ratio 2/1. The patients participated in an H. pylori eradication study in which they randomly received active eradication therapy. Endoscopy was performed before H. pylori eradication therapy and after 8 and 52 weeks, with specimens examined according to the Sydney system.

RESULTS

Of the 92 patients, 8 (9%) had panatrophy, 58 (63%) had antral- and 26 (28%) had corpus-predominant atrophic gastritis. After H. pylori eradication, the mean atrophy score declined in patients with antral-predominant atrophy from 1.5 (mean) to 0.7 (p<0.05), in corpus-predominant atrophy from 1.7 to 0.2 (p=NS) and in patients with panatrophy from 1.2 to 0.8 (p=NS). Atrophy healing was seen in 55% of antral-predominant atrophy patients who had successful H. pylori eradication. The mean antral atrophic score in one year declined in patients with duodenal ulcer (from 1.0 mean to 0.4) whereas it remained the same (1.3) in those with gastric ulcer (p<0.05).

CONCLUSIONS

Atrophy can diminish or even disappear, especially in the antrum, during a 1-year follow-up after eradication of infection. Atrophy progression seems milder in patients with duodenal ulcer than in patients with gastric ulcer.

Causal role of Helicobacter pylori infection in gastric cancer: An Asian enigma

Helicobacter pylori (H pylori) has been etiologically linked to gastric cancer. H pylori infection is more frequent in less developed Asian countries like India, Bangladesh, Pakistan, and Thailand and is acquired at early age than in more developed Asian countries like Japan and China. Frequency of gastric cancer, however, is very low in India, Bangladesh, Pakistan and Thailand compared to that in Japan and China. Similar enigma has been reported from Africa as compared to the West. Seroprevalence of H pylori infection in adult populations of India, Bangladesh, Pakistan and Thailand varies from 55% to 92%. In contrast, seroprevalence of H pylori in Chinese and Japanese adults is 44% and 55%, respectively. Annual incidence rate of gastric cancer in India, Bangladesh, and Thailand is 10.6, 1.3, 7.1 per 100 000 populations, respectively; in contrast, that in China and Japan is 32-59 and 80-115 per 100 000 populations, respectively. Several studies from India failed to show higher frequency of H pylori infection in patients with gastric cancer than controls. Available evidences did not support difference in H pylori strains as an explanation for this enigma. Despite established etiological role of H pylori, situation is somewhat enigmatic in Asian countries because in countries with higher frequency of infection, there is lower rate of gastric cancer. Host’s genetic make-up and dietary and environmental factors might explain this enigma. Studies are urgently needed to solve this issue.

Helicobacter pylori phase variation, immune modulation and gastric autoimmunity

Helicobacter pylori can be regarded as a model pathogen for studying persistent colonization of humans. Phase-variable expression of Lewis blood-group antigens by H. pylori allows this microorganism to modulate the host T-helper-1-cell versus T-helper-2-cell response. We describe a model in which interactions between host lectins and pathogen carbohydrates facilitate asymptomatic persistence of H. pylori. This delicate balance, favourable for both the pathogen and the host, could lead to gastric autoimmunity in genetically susceptible individuals.

Gastric cancer risk in a Mexican population: role of Helicobacter pylori CagA positive infection and polymorphisms in interleukin-1 and -10 genes

Several polymorphisms of the IL1B and IL10 gene promoters have been reported to be associated with gastric cancer risk in Caucasians. However, studies in other populations have shown differing results. We aimed to test for associations between polymorphisms in IL1B (-31 and +3954), IL10-592 and IL1RN variable number of tandem repeats (VNTR) and risk of gastric cancer in a Mexican population. DNA was extracted from sera of 183 gastric adenocarcinoma patients and 377 controls. The IL1B-31, IL1B+3954 and IL10-592 biallelic polymorphisms were discriminated using 5' Nuclease (TaqMan) assays and Pyrosequencing. The IL1RN penta-allelic VNTR polymorphism was genotyped using PCR followed by GeneScan analysis. A significant interaction was found between IL1B-31 and CagA status for the risk of intestinal-type gastric cancer (p = 0.023). Among CagA positive subjects, those with IL1B-31CC genotype had an increased risk of intestinal-type gastric cancer (OR 3.19, 95%CI = 1.05-9.68), compared to carriers of IL1B-31TT genotype. In contrast, among CagA negative subjects, no significant association of IL1B-31CC genotype with gastric cancer was observed. The IL10-592CC genotype was associated with more than doubling of the risk of the intestinal-type gastric cancer (OR, 2.20, 95%CI = 1.04-4.65). A nonsignificantly increased risk for intestinal-type gastric cancer was found in IL1RN*2 carriers (OR 1.49, 95%CI = 0.89-2.50). None of these polymorphisms was significantly related to the risk of diffuse-type gastric cancer. No significant association was found between risk of gastric cancer and the IL1B+3954 polymorphism. Individuals carrying 2 or more of the risk-associated alleles (IL1B-31C, IL1RN *2 and IL10-592C) were at increased risk for intestinal-type gastric cancer, compared to those with 0 or 1 risk-associated allele. The risk from multiple risk-associated alleles was especially high in subjects infected with CagA positive H. pylori. Our results support the identification of the IL1B-31 promoter polymorphism as a useful marker for risk of intestinal type gastric cancer in persons with CagA positive H. pylori infections.

Western blotting of total lysate of Helicobacter pylori in cases of atrophic body gastritis

BACKGROUND

Atrophic body gastritis is considered the first important step in the histogenesis of gastric carcinoma, a multistep process starting from chronic gastritis and progressing through chronic atrophic gastritis, intestinal metaplasia, and dysplasia. Helicobacter pylori is involved in the induction of atrophic body gastritis, but documentation of H. pylori infection is difficult because of the progressive disappearance of the bacterium. Our study aimed to detect past H. pylori infection in patients with atrophic body gastritis.

METHODS

We used Western blot analyses of whole bacterial protein lysate of 2 different strains to probe sera from 143 patients. All sera were analyzed by ELISA (Bio-Rad), and results of gastric histology were available for all patients.

RESULTS

Among 111 patient sera previously classified as negative for H. pylori infection by ELISA, 106 (95.5%) were positive when assayed by immunoblotting.

CONCLUSIONS

Commercial diagnostic reagent sets may fail to detect H. pylori infection. Western blotting of whole bacterial protein extracts could provide the basis of a noninvasive serology tool able to assess previous infection with H. pylori in patients with atrophic body gastritis.

Of microbe and man: determinants ofHelicobacter pylori-related diseases

The human gastric pathogen Helicobacterpylori infects the human gastric mucus layer of approximately half of the world's population. Colonization with this bacterium results in superficial gastritis without clinical symptoms, but can progress into gastric or duodenal ulcers, gastric malignancies and mucosa-associated lymphoid tissue-lymphomas. Disease outcome is affected by a complex interplay between host, environmental and bacterial factors. Irrespective of disease outcome, the majority of H. pylori infected individuals remain colonized for life. Changing conditions in the human gastric mucosa may alter gene expression and/or result in the outgrowth of more fit H. pylori variants. As such, H. pylori is a highly flexible organism that is optimally adapted to its host. the heterogeneity in H. pylori populations make predictions on H. pylori-related pathogenesis difficult. In this review, we discuss host, environmental and bacterial factors that are important in disease progression. Moreover, H. pylori adaptive mechanisms, which allow its life-long survival and growth in the gastric mucosa are considered.

Diagnostic accuracy of the serum profile of gastric mucosa in relation to histological and morphometric diagnosis of atrophy

BACKGROUND

Histology is the gold standard for diagnosis of atrophy but is hampered by observer variation. A reliable method to overcome this issue is morphometric analysis of gastric mucosa. Serum pepsinogens and gastrin have been proposed in the diagnostic work-up of gastric atrophy although diagnostic accuracy of these tests is considered unsatisfactory.

AIM

To evaluate the diagnostic accuracy of gastric serum profile in relation both to morphological and morphometric diagnosis of gastric atrophy.

METHODS

Ninety-four dyspeptic out-patients underwent upper endoscopy and evaluation of serum levels of PGI, PGII and 17-gastrin. Diagnostic accuracy of gastric serum profile was tested by receiver operating characteristic curves and by evaluation of sensitivity and specificity in relation to both histology and morphometric analyses.

RESULTS

As far as concern to histological evaluation, only PGI/PGII ratio showed an acceptable diagnostic accuracy in discrimination of gastric atrophy, while, when morphometric analysis was considered as reference, both serum PGI level and PGI/PGII ratio showed an excellent performance. However, both PGI and PGI/PGII ratio showed low sensitivity and high specificity.

CONCLUSIONS

Serological gastric profile corresponds better with the morphometric diagnosis of atrophy, even if, because of the low sensitivity, today this could only be used as screening test of chronic atrophic gastritis.

Recovery of gastric function after Helicobacter pylori eradication in subjects with body atrophic gastritis: prospective 4-year study

BACKGROUND

The relationship between Helicobacter pylori (H. pylori) eradication and atrophic changes in the gastric mucosa has not yet been fully defined. Although studies report a partial restoration of serum pepsinogen I (sPGI) levels after eradication, it is not clear if this finding reflects gastric mucosal healing on a morphological level.

AIM

To assess alterations in gastric function after H. pylori eradication on moderate/severe body atrophic gastritis by determination of sPGI levels.

METHODS

Twenty-three dyspeptic patients, selected from 284 consecutive H. pylori positive patients, with histological features of moderate/severe body atrophic gastritis and sPGI < 25 microg/L (11 men, mean age: 51.8 years, range: 29-79 years), underwent an upper gastrointestinal endoscopy with gastric biopsies and sPGI determination at baseline. All patients underwent eradication therapy. Serum pepsinogen I was measured again after 6 months, and at 1, 2, 3 and 4 years after eradication therapy.

RESULTS

Mean sPGI levels prior to eradication were 11.9 microg/L (range: 4-23 microg/L). Six months after eradication therapy, mean sPGI levels significantly increased to 17.4 microg/L (P = 0.04). At the completion of the study, 4 years after eradication, sPGI levels increased from 17.4 to 32.7 microg/L (P = 0.01). A significant progressive increase in sPGI levels was observed from 6 months to 1 year (17.4 to 23.9 microg/L) and from 1 to 2 years (23.9 to 26.0 microg/L, P = 0.01). Serum pepsinogen I levels higher than the cut-off value of 25 microg/L were observed at various time-points: 6.3% of patients at 6 months (1/16), 33.3% (5/15) at 1 year, 50% (7/14) at 24 months, 66.7% (6/9) at 36 months and 87.5% (7/8) at 4 years.

CONCLUSION

After H. pylori eradication, subjects with body atrophic gastritis showed long-term improvement of physiological gastric function, reflected by significantly and continually increasing sPGI levels over a 4-year period.

Racial differences in Helicobacter pylori, serum pepsinogen and gastric cancer incidence in an urban Asian population

BACKGROUND

In Singapore, the highest incidence of gastric cancer occurs in the Chinese (C), with lower rates among Malay (M) and Indian (I) subjects. The purpose of the present paper was to examine whether racial differences in the prevalence of Helicobacter pylori and serum pepsinogen (PG) could account for this difference.

METHODS

A randomized community health survey involving 7000 asymptomatic healthy individuals was conducted. Among the Chinese, Malay and Indian respondents, subjects were matched for age, gender and race and a total of 595 sera were obtained. The H. pylori seropositivity and serum PG levels were determined by ELISA. The dependency of the cumulative gastric incidence rate on H. pylori seroprevalence was evaluated by linear regression. The racial difference in the seroprevalence of H. pylori and low serum PG was determined.

RESULTS

The H. pylori seroprevalence was similar between Chinese and Indian subjects, but significantly lower among Malay subjects (C, 46.3%; M, 27.9%; I, 48.1%). The gastric cancer incidence rates correlated with H. pylori seropositivity for the Chinese and Malay subjects, but not for the Indian subjects. The prevalence of low PG was highest in Indian subjects (PG I low: C, 2.1%; M, 5.4%; I, 14.2%; P < 0.0001; PG I:II ratio low: C, 5.3%; M, 5.9%; I, 12.6%; P = 0.012), even when adjusted for gender and the presence of H. pylori.

CONCLUSIONS

The difference in gastric cancer incidence correlated with H. pylori seroprevalence for Chinese and Malay subjects. The lower incidence of gastric cancer among Indian subjects cannot be explained by differences in H. pylori or serum PG. Other modifying factors such as host and environmental factors may be important.

The best method of detecting prior Helicobacter pylori infection

AIM

Prior Helicobacter pylori (H pylori) infection has often been underestimated. These underestimations have misled physicians attempting to determine the significance between H pylori and certain gastrointestinal lesions such as intestinal metaplasia, atrophic gastritis, and gastric cancer. Our study endeavored to detect past H pylori infections accurately, easily, and rapidly with the newly developed immunoblot kit, Helico Blot 2.1.

METHODS

Thirty-three patients, including 25 H pylori infected and 8 uninfected cases, were enrolled in our study. All patients received consecutive gastroendoscopic examinations and (13)C-urea breath test (UBT) tests at 6- or 12-mo intervals for up to 4 years. Serum samples were obtained from each patient at the same time. Intragastric H pylori infection was confirmed in accordance with the gold standard. Twenty-five H pylori-infected patients received triple therapies after initial bacterial confirmation, and were successful in eradicating their infections. Serially obtained sera were tested by means of Helico Blot 2.1.

RESULTS

Current infection marker detected by Helico Blot 2.1 was unreliable for representing ongoing H pylori infection. Only 35 and 37 ku antibodies of H pylori had significant seroconversion rates 1 year after having been cured. The seropositive rates of 116 ku (cytotoxin-associated antigen (CagA)) and Helico Blot 2.1 were nearly 100% during 4-year follow-up period. Both CagA antigen and Helico blot 2.1 could serve as indicators of long-term H pylori infection.

CONCLUSION

Helico Blot 2.1 can detect past H pylori infections for up to 4 years, and is the best method to date for detecting previous long-term H pylori infection.

Lack of specific association between gastric autoimmunity hallmarks and clinical presentations of atrophic body gastritis

AIM: To investigate the possible relationships between gastric autoimmune phenomena and clinical presentations of this disorder, in consecutive atrophic body gastritis patients.

METHODS: A total of 140 atrophic body gastritis patients, diagnosed as consecutive outpatients presenting with macrocytic or iron deficiency anemia, or longstanding dyspepsia underwent gastroscopy with antral and body biopsies, assay of intrinsic factor, parietal cells and Helicobacter pylori (H pylori) antibodies. Gastritis was assessed according to Sydney System.

RESULTS: Parietal cell antibodies were equally distributed in all clinical presentations, whereas the positivity of intrinsic factor antibodies (49/140, 35%) was significantly higher in pernicious anemia patients (49.2%) than in iron deficiency (21.1%) and dyspeptic patients (27.8%). No specific pattern of autoantibodies was related to the clinical presentations of atrophic body gastritis. A positive correlation was obtained between the body atrophy score and the intrinsic factor antibody levels (r = 0.2216, P = 0.0085). Associated autoimmune diseases were present in 25/140 (17.9%) patients, but the prevalence of autoimmune diseases was comparable, irrespective of the clinical presentations.

CONCLUSION: The so-called hallmarks of gastric autoimmunity, particularly in intrinsic factor antibody cannot be usefully employed in defining an autoimmune pattern in the clinical presentations of ABG.

Helicobacter pylori antibodies and gastric cancer: a gender-related difference

Helicobacter pylori has been proposed as a causative agent of gastric cancer. The aim of this study was to define serum antibodies response against different H. pylori antigens in patients with gastric cancer. Serum samples were collected from 115 Lithuanian patients with non-cardia gastric cancer and 110 age- and sex-matched controls without cancer. Heat-stable, low-molecular-mass, and outer membrane proteins were used as antigens to analyze serum IgG antibody response against H. pylori by enzyme-linked immunosorbent assay. Seroprevalence of H. pylori using low-molecular-mass antigen was significantly higher in gastric cancer patients, compared to controls (77% versus 57%, p<0.05). Significant differences in the prevalence of H. pylori infection between gastric cancer patients and controls were found in females using all three studied antigens: heat-stable (98% versus 84%, p<0.05), low-molecular-mass (88% versus 48%, p<0.05) and outer membrane proteins (78% versus 57%, p<0.05). In males, no significant differences were revealed between gastric cancer patients and controls. There may be other cofactors in addition to H. pylori that are important for the development of gastric cancer. H. pylori seems, however, to be a more important for development of gastric cancer in females than in males or males may have more confounding risk factors for gastric cancer than females.

Prevalence of gastric cancer decreases with age in long-living elderly in Japan, possibly due to changes in Helicobacter pylori infection status

OBJECTIVES

The prevalence of Helicobacter pylori (Hp) infection and the development of gastric cancer are both believed to increase with age in Japan. However, no studies have investigated people older than 65 years in detail. In this study, we investigated the prevalence of Hp infection and gastric cancer in the elderly, and analyzed the influence of both factors on longevity.

METHODS

All patients investigated were 65 years old and over. A total of 1877 autopsy cases were used to investigate the prevalence of gastric cancer and colonic cancer. Serum samples were obtained from 644 patients with dyspepsia and analyzed for Hp-IgG antibodies. Of these 644 patients, 63 underwent upper gastrointestinal endoscopies. Five biopsies were obtained and evaluated for the following morphological variables: neutrophils, mononuclear cell, atrophy, and intestinal metaplasia. Hp infection was evaluated histologically and with the (13)C-urea breath test.

RESULTS

The prevalence of gastric cancer was significantly lower in subjects older than 85 years. The positive rate of serum Hp-IgG, and Hp infection as detected histologically and by the (13)C-urea breath test, also decreased with age. In Hp(+) patients, the neutrophil score significantly decreased with age. In Hp(-) patients, however, the intestinal metaplasia score significantly increased with age.

CONCLUSIONS

The non-infection of Hp itself is not related to longevity in Japanese elderly, because even Hp(-) patients appear to have been infected previously with Hp. The lower prevalence of gastric cancer in the elderly may be due to the disappearance of Hp colonization, which may contribute to longevity in Japanese elderly.

Unraveling the mystery of the gastroesophageal junction: a pathologist's perspective

The gastroesophageal junction (GEJ), which is defined as the point where the distal esophagus joins the proximal stomach (cardia), is a short anatomic area that is commonly exposed to the injurious effects of GERD and/or Helicobacter pylori infection. These disorders often lead to inflammation and intestinal metaplasia (IM) of this anatomic region. The true gastric cardia is an extremely short segment (<0.4 mm) of mucosa that is typically composed of pure mucous glands, or mixed mucous/oxyntic glands that are histologically indistinguishable from metaplastic mucinous columnar epithelium of the distal esophagus. In patients with GERD, whether physiologic or pathologic, the length of cardia-type epithelium increases and extends proximally above the level of the anatomic GEJ into the distal esophagus. Columnar metaplasia of the distal esophagus represents a squamous to columnar metaplastic reaction that develops from an esophageal stem cell and may pass through an intermediate phase characterized by the presence of a type of epithelium that possesses a mixture of squamous and columnar features, termed multilayered epithelium. In contrast, IM of the gastric cardia represents a columnar to columnar cell metaplastic reaction that develops from a gastric stem cell located in the deep foveolar compartment of the gastric mucosa. Intestinal metaplasia, particularly the incomplete type, is widely believed to represent the precursor lesion upon which dysplasia and cancer arises. The frequency of IM is probably greater in metaplastic columnar epithelium in the esophagus secondary to GERD, than in cases of true gastric carditis secondary to H. pylori, and may be a reason why there is a higher risk of carcinoma in the former compared to the latter. A variety of clinical, endoscopic, histologic, and histochemical methods can be used to distinguish GERD-induced columnar metaplasia of the distal esophagus from H. pylori-induced inflammation of true gastric cardia, and these are outlined in this review, but further controlled studies are needed to critically evaluate these techniques. Further prospective trials are needed to adequately evaluate the different etiologic and pathogenetic mechanisms and, most importantly, the risk of malignancy in these two conditions.

The Development of Therapeutic and Preventive Vaccines for Gastric Cancer and Helicobacter pylori

Gastric cancer is one of the most important worldwide public health problems. Convincing epidemiologic and etiologic associations have been made between the development of gastric cancer and infection with Helicobacter pylori. H. pylori not only has adapted to survive within the harsh environment of the stomach but also is able to modulate and avoid endogenous immune responses. The design and creation of efficacious vaccine strategies against H. pylori requires an understanding of the complex interactions that make up mucosal immunity. An effective vaccine strategy against H. pylori has the potential to affect significantly on population health worldwide.

Clinical usefulness of serum pepsinogens I and II, gastrin-17 and anti-Helicobacterpylori antibodies in the management of dyspeptic patients in primary care

BACKGROUND

Several tests have been proposed for evaluating dyspeptic symptoms and their relationship to the underlying gastric disease. Serum pepsinogens and gastrin-17 are known to be useful biomarkers for the detection of gastric pathologies.

AIM

To evaluate the capability of screening dyspeptic patients in the primary care by analyses of serum pepsinogens I (sPGI) and II (sPGII), gastrin-17 (sG-17) and the IgG anti-Helicobacter pylori antibodies (IgG-Hp).

PATIENTS AND METHODS

Three hundred and sixty-two consecutive patients with dyspeptic symptoms (208 females, mean age 50.6 +/- 16 years, range 18-88 years) referred by general practitioners for upper gastrointestinal endoscopy were enrolled. A blood sample was taken from each subject for IgG-Hp, sPGI, sPGII and sG-17 analyses.

RESULTS

Two hundred and eighty-seven patients had a complete screening; of these, 132 resulted positive for Hp infection. Patients with atrophic chronic gastritis showed significantly lower serum pepsinogen I levels and sPGI/sPGII ratio than patients with non-atrophic chronic gastritis. Moreover, by calculating the values of sPGI by sG-17 and sG-17 by sPGII/sPGI, subjects with atrophic chronic gastritis could be distinguished from those with non-atrophic chronic gastritis and from those with normal mucosa, respectively. sG-17 levels were found to be a useful biomarker for the detection of antral atrophic gastritis, while the combination of sPGI, the sPGI/sPGII ratio and sG-17 was found effective in identifying corpus atrophy.

CONCLUSION

A panel composed of PGI, PGII, G-17 and IgG-Hp could be used as a first approach in the 'test and scope' and/or 'test and treat' strategy in the primary care management of dyspeptic patients.

Histamine-2 receptor expression in gastric mucosa before and after Helicobacter pylori cure

BACKGROUND

Helicobacter pylori infection prevents the occurrence of the tolerance phenomenon of Histamine-2 (H2) receptor antagonists. Gastro-esophageal reflux disease develops in some cases with the restoration of acid secretion after H. pylori eradication therapy.

AIM

To clarify the mechanisms of H2 receptor restoration after the eradication of H. pylori on parietal cells.

METHODS

We enrolled 80 consecutive asymptomatic male patients with H. pylori infection, having chronic gastritis with or without the presence of peptic ulcers. Biopsy specimens from the greater curvatures at the mid-corpus of the stomach were obtained endoscopically from all subjects before and 12 weeks after the eradication of H. pylori. Degrees of gastric atrophy were evaluated by serum pepsinogen levels. The amounts of mRNA expression of H2 receptor were evaluated in each subject's gastric mucosa by real time reverse transcriptase-polymerase chain reaction (RT-PCR).

RESULTS

H2 receptor mRNA expression levels significantly correlated with serum pepsinogens I and II ratios. The expression level of H2 receptor mRNA was lower in subjects with hypergastrinemia. The median expression level of H2 receptor after H. pylori eradication was threefold greater than prior to treatment. In addition, its restoration became more pronounced in subjects with severe gastric atrophy. However, a comparatively low restoration of H2 receptor mRNA was found in subjects with hypergastrinemia.

CONCLUSIONS

H2 receptor mRNA levels decrease with the progression of gastric atrophy induced by H. pylori infection, and are restored after H. pylori eradication. Such expression levels of H2 receptor may explain a part of the tolerance phenomenon to H2 receptor antagonists.

Age-dependent accuracy of Helicobacter pylori antibody assays for adults, with special emphasis on atrophic gastritis

The accuracy of Helicobacter pylori antibody assays for 561 consecutive adult outpatients who had undergone gastroscopy was studied. The sensitivity of an immunoglobulin G test was 99 to 100% for all age groups, but the specificity declined by age group, from 99% for those aged 15 to 49 years to 75% for those aged > or =65 years. The exclusion of false-positive results for patients with atrophic gastritis improved the specificity to 93 to 97% for the older age groups.

Helicobacter pylori infection and low serum pepsinogen I level as risk factors for gastric carcinoma

AIM: To study whether examination of CagA antibodies could increase the odds ratio for gastric cancer in a case-control study, and how often other serum markers of gastric cancer risk could be found in Helicobacter pylori -negative patients.

METHODS: H pylori CagA and parietal cell antibodies (PCAs), and serum pepsinogen I (SPGI) levels were compared between patients with gastric cancer and controls who received endoscopic examination due to reasons other than gastrointestinal malignancy.

RESULTS: The odds ratio (OR) for gastric cancer was 2.9 (95% CI 1.4-5.8) in H pylori+ patients, and 2.4 (95% CI 1.2-4.9) in CagA+ patients. When results of H pylori and CagA antibodies were combined, OR increased to 5.0 (95% CI 2.5-10.0). Furthermore, if cardia cancer patients were excluded, the OR increased to 6.8 (95% CI 3.1-14.8). Among patients with a low SPGI level, the OR was 12.0 (95% CI 4.1-35.3). However, the risk was significant only in the older age group. The number of patients with low SPGI was significantly higher in H pylori-/CagA+ patients as compared to other cancer patients.

CONCLUSION: Examination of both H pylori and CagA antibodies increases the OR for gastric cancer in our case-control study. CagA antibodies are important in detecting previous H pylori infection in advanced atrophic gastritis or cancer when spontaneous decline of H pylori antibodies occurs. SPGI may be helpful in screening elderly gastric cancer patients.

Helicobacter pylori Infection among Patients Visiting a Clinic in Kasama City, Ibaraki Prefecture

We examined Helicobacter pylori infection in patients who visited the Iso Clinic (Kasama City, Ibaraki Prefecture) with abdominal complaints, and determined the prevalence of H. pylori infection by age, sex, endoscopic diagnosis, abdominal complaint, gastric mucosa, and living environment. Peptic ulcer disease was observed in 23.2% of the patients examined with endoscopy, but there was no association between abdominal complaints and the prevalence of H. pylori infection. The prevalence of H. pylori infection was high among patients with peptic ulcer disease and atrophic gastritis. The prevalence of H. pylori infection was higher in the generation born before tae start of the period of rapid economic growth (71.5%) than in the generation born afterward (64.8%). No significant difference was observed between males and females. The prevalence of H. pylori infection was high in those who drank well water during childhood and those who were raised in a house with a nonflushing of toilet (67.2% and 67.5%, respectively). There were no associations with river basin of residence, alcohol consumption, or smoking. The prevalence of H. pylori infection among patients who visited Iso Clinic was higher than that among patients seen at Tama-Nagayama Hospital, Nippon Medical School (Tama City, Tokyo). The difference is attributable to the higher prevalence of H. pylori infection in the elderly.

Helicobacter infection and gastric neoplasia

Chronic gastritis induced by Helicobacter pylori is the strongest known risk factor for adenocarcinoma of the distal stomach, yet only a minority of people who harbour this organism ever develop cancer. H. pylori isolates possess substantial genotypic diversity, which engenders differential host inflammatory responses that influence clinical outcome. H. pylori strains that possess the cag pathogenicity island and secrete a functional cytotoxin induce more severe gastric injury and further augment the risk for developing distal gastric cancer. However, carcinogenesis is also influenced by host genetic diversity, particularly involving immune response genes such as IL-1ss and TNF-alpha. It is important to gain insight into the pathogenesis of H. pylori-induced gastritis and adenocarcinoma, not only to develop more effective treatments for gastric cancer, but also because it might serve as a paradigm for the role of chronic inflammation in the genesis of other malignancies that arise within the gastrointestinal tract.

Gastric autoimmunity: the role of Helicobacter pylori and molecular mimicry

Pathogens can induce autoreactive T cells to initiate autoimmune disease by several mechanisms. Pathogen-induced inflammation results in the enhanced presentation of self antigens, which causes the expansion of the activated autoreactive T cells that are required for disease onset. Alternatively, a pathogen might express antigens with epitopes that are structurally similar to epitopes of autoantigens, resulting in a mechanism of molecular mimicry. This is the case for Helicobacter pylori-associated human autoimmune gastritis, in which the activated CD4+ Th1 cells that infiltrate the gastric mucosa cross-recognize the epitopes of self gastric parietal cell H(+)K(+)-ATPase and of various H. pylori proteins. Therefore, in genetically susceptible individuals, H. pylori infection can start or worsen gastric autoimmunity, leading to atrophic gastritis.

Persistent bacterial infections: the interface of the pathogen and the host immune system

Persistent bacterial infections involving Mycobacterium tuberculosis, Salmonella enterica serovar Typhi (S. typhi) and Helicobacter pylori pose significant public-health problems. Multidrug-resistant strains of M. tuberculosis and S. typhi are on the increase, and M. tuberculosis and S. typhi infections are often associated with HIV infection. This review discusses the strategies used by these bacteria during persistent infections that allow them to colonize specific sites in the host and evade immune surveillance. The nature of the host immune response to this type of infection and the balance between clearance of the pathogen and avoidance of damage to host tissues are also discussed.

Serum antibodies to Helicobacter pylori and its heat-shock protein 60 correlate with the response of gastric mucosa-associated lymphoid tissue lymphoma to eradication of H. pylori

BACKGROUND AND AIMS

Eradication of Helicobacter pylori leads to regression of mucosa-associated lymphoid tissue (MALT) lymphomas. In this study, we measured serum antibodies to H. pylori and H. pylori-recombinant heat-shock protein 60 (rHSP60) in patients with gastric MALT lymphoma to determine whether humoral immune responses to the bacterial antigens correlate with the efficacy of eradication therapy.

METHODS

Serum samples were obtained from 33 patients with H. pylori-positive gastric MALT lymphoma before undergoing therapy to eradicate the bacteria. Anti-H. pylori antibodies were measured in a commercial assay and in immunoassays to lysates and rHSP60 which were prepared from ATCC 43504 strain.

RESULTS

Helicobacter pylori were eradicated in all 33 patients, and the lymphoma completely regressed histologically in 26 patients (79%). Pre-treatment titers of serum antibody to H. pylori and to rHSP60 in the patients whose tumor regressed were significantly higher than titers in patients whose tumors did not regress (p =.0011 and.035, respectively). By logistic regression analysis, age (odds ratio = 0.88, 95% confidence interval = 0.80-0.99), endoscopic appearance (0.053, 0.004-0.65), titers of anti-H. pylori antibodies (67.6, 2.5-1800), and titers of anti-rHSP60 antibody (6.4, 1.2-36) were identified as significantly associated factors with the outcome of MALT lymphoma.

CONCLUSIONS

Measurement of serum antibodies to H. pylori and HSP60 might be useful for predicting the response of gastric MALT lymphoma to eradication of H. pylori.

Progression of chronic atrophic gastritis associated with Helicobacter pylori infection increases risk of gastric cancer

We conducted a longitudinal cohort study to determine the association of Helicobacter pylori infection and the progression of chronic atrophic gastritis (CAG) with gastric cancer. A cohort of 4655 healthy asymptomatic subjects was followed for a mean period of 7.7 years. H. pylori infection was established by serum specific antibodies and the presence of CAG was confirmed by serum pepsinogen. During the follow-up period, 45 gastric cancer cases were detected (incidence rate, 126/100000 person-years). A univariate analysis after adjustment for age showed that both H. pylori and CAG were significantly associated with gastric cancer. To clarify the interaction between H. pylori and CAG, an analysis stratified by H. pylori- and CAG-status was performed. No cancer developed in the H. pylori(-)/CAG(-) group during the study period. This supports the theory that it is quite rare for any type of gastric cancer to develop in an H. pylori-free healthy stomach. With the progression of H. pylori-induced gastritis, the risk of gastric cancer increased in a stepwise fashion from CAG-free gastritis [H. pylori(+)/CAG(-) group] (HR=7.13, 95%CI=0.95-53.33) to CAG [H. pylori(+)/CAG(+) group] (HR=14.85, 95%CI=1.96-107.7) and finally to severe CAG with extensive intestinal metaplasia [H. pylori(-)/CAG(+) group] (HR=61.85, 95%CI=5.6-682.64) in which loss of H. pylori from the stomach is observed. Therefore, it is probable that H. pylori alone is not directly associated with stomach carcinogenesis. Instead, H. pylori appears to influence stomach carcinogenesis through the development of CAG. The observed positive correlation between the extent of H. pylori-induced gastritis and the development of cancer was strong, especially for the intestinal type. These results are compelling evidence that severe gastritis with extensive intestinal metaplasia is a major risk factor for gastric cancer, and they confirm the previously described model of stomach carcinogenesis: the gastritis-metaplasia-carcinoma sequence.

Natural acquisition of Helicobacter pylori infection in newborn rhesus macaques

Helicobacter pylori infection is usually acquired in childhood, but precise estimates of the age of acquisition are difficult to obtain in young children. Since serial endoscopic biopsies are not feasible in human infants, we examined acquisition of H. pylori infection that is known to occur in socially housed nonhuman primates. By 12 weeks of age, 8 of 20 newborns (40%) were culture positive for H. pylori, and prevalence reached 90% by 1 year of age. Newborns from infected dams were more commonly infected than those from uninfected dams, particularly during the peripartum period, suggesting that close contact during this time may facilitate transmission. Transient infection was uncommon and occurred only after the first positive culture. These results suggest that in a high-prevalence environment, persistent H. pylori infection may be acquired at an earlier age than was previously thought. Since clean, potable water was readily available, contamination of water supply is not essential for widespread infection at an early age in areas where hygiene is otherwise poor. Furthermore, breastfeeding seems to offer little protection, since newborn macaques breastfeed during the first year of life and typically are fully weaned only when another newborn arrives the following spring.

Helicobacter pylori infection and gastric autoimmune diseases: is there a link?

BACKGROUND

Helicobacter pylori is thought to be involved in atrophic body gastritis. We explored the prevalence of H. pylori infection in asymptomatic subjects with gastric parietal cell antibodies, as well as in patients with pernicious anemia, to evaluate a possible role of H. pylori gastric infection in gastric autoimmunity.

PATIENTS AND METHODS

We studied 79 consecutive asymptomatic subjects with parietal cell antibodies, 24 patients with pernicious anemia, and 66 parietal cell antibody-negative controls. All patients underwent gastric biopsies for histology and detection of H. pylori. Red blood cell count and volume, serum levels of gastrin, pepsinogen I, iron, folic acid, vitamin B12, and circulating antibodies to H. pylori and to intrinsic factor were also determined.

RESULTS

We found an atrophic body gastritis in 14 of the 79 asymptomatic subjects with parietal cell antibodies (18%) and in 2 of the 66 controls (3%) (p =.01). Mean levels of gastrin were increased (p <.0001), while those of pepsinogen were reduced (p <.001) compared with controls. H. pylori was identified at the gastric level and/or circulating anti-H. pylori antibodies were detected in 46 parietal cell antibody-positive subjects (58%) compared with 26 controls (39%) (p =.03). In patients with pernicious anemia we found an atrophic body gastritis in 18 of 24 cases (75%) (p <.001 vs. controls). Mean levels of gastrin were markedly increased (p <.0001) and those of pepsinogen I decreased (p <.0001) relative to controls. Only five of these patients (21%) had evidence of H. pylori infection compared with 46 of the parietal cell antibody-positive subjects (58%) (p =.003) and 26 of the controls (39%). Considering all patients with gastric autoimmunity (i.e. with parietal cell antibodies and/or with pernicious anemia), H. pylori was found in 44 of 72 of those without atrophy (61%) but in 6 of 31 with gastric body atrophy (19%) (p <.001), indicating that H. pylori infection is greatly reduced when gastric acid secretion decreases.

CONCLUSIONS

The frequent detection of H. pylori infection in subjects with early gastric autoimmunity, indicated by the presence of parietal cell antibodies, suggests that H. pylori could have a crucial role in the induction and/or the maintenance of autoimmunity at the gastric level.

'Serological biopsy' in first-degree relatives of patients with gastric cancer affected by Helicobacter pylori infection

BACKGROUND

Relatives of patients with gastric cancer are at increased risk of developing this disease, especially if they are infected by Helicobacter pylori. Moreover, H. pylori-related atrophic gastritis and hypochlorhydria are well-documented risk factors for noncardia gastric cancer. Serum pepsinogen I (sPGI) and II (sPGII) levels are low in this condition. The aim of our study was to assess by means of a 'Gastropanel' blood test, including sPGI, sPGII, gastrin-17 (G-17) and antibodies anti-H. pylori (IgG-Hp). both functional and morphological features of gastric mucosa in Hp + ve subjects with a family history of gastric cancer.

MATERIALS AND METHODS

Twenty-five Hp + ve subjects consecutively referred to our department for gastrointestinal complaints, selected as first-degree relatives of patients suffering from gastric cancer, were enrolled in the study and then matched for sex and age with 25 dyspeptic and Hp + ve subjects with no family history of gastric neoplasia. Blood samples were taken for determination of gastropanel in all patients; in addition, antibodies against CagA were analysed.

RESULTS

No statistically significant differences were detected between the two groups as regards alcohol consumption, coffee intake and smoking habits. Mean sPGI levels in Group A (83.4 +/- 58.4 microg/L) were significantly lower than those in Group B (sPGI 159.5 +/- 80.6 microg/L; P < 0.0001) as well as sPGII (12.5 microg/L = 6.24 versus 20.6 +/- 58 microg/L; P < 0.006). No statistical difference was found between the two groups in relation to G-17 levels, IgG-Hp titres and antibodies against CagA.

CONCLUSION

First-degree relatives of patients with noncardia gastric cancer affected by H. pylori infection present lower sPGI and sPGII levels, possibly due to the increased frequency of atrophic lesions in these patients.

Population attributable risks of esophageal and gastric cancers

BACKGROUND

Several risk factors have been identified for esophageal adenocarcinoma, gastric cardia adenocarcinoma, esophageal squamous cell carcinoma, and noncardia gastric adenocarcinoma, but no study has comprehensively examined their contributions to the cancer burden in the general population. Herein, we estimate the population attributable risks (PARs) for various risk factors observed in a multicenter population-based case-control study.

METHODS

We calculated PARs by using 293 patients with esophageal adenocarcinoma, 261 with gastric cardia adenocarcinoma, 221 with esophageal squamous cell carcinoma, 368 with noncardia gastric adenocarcinoma, and 695 control subjects. We included smoking for all four tumor types and Helicobacter pylori infection for noncardia gastric adenocarcinoma as established causal risk factors as well as several other factors for which causality is under evaluation.

RESULTS

Ever smoking, body mass index above the lowest quartile, history of gastroesophageal reflux, and low fruit and vegetable consumption accounted for 39.7% (95% confidence interval [CI] = 25.6% to 55.8%), 41.1% (95% CI = 23.8% to 60.9%), 29.7% (95% CI = 19.5% to 42.3%), and 15.3% (95% CI = 5.8% to 34.6%) of esophageal adenocarcinomas, respectively, with a combined PAR of 78.7% (95% CI = 66.5% to 87.3%). Ever smoking and body mass index above the lowest quartile were responsible for 45.2% (95% CI = 31.3% to 59.9%) and 19.2% (95% CI = 4.9% to 52.0%) of gastric cardia adenocarcinomas, respectively, with a combined PAR of 56.2% (95% CI = 38.1% to 72.8%). Ever smoking, alcohol consumption, and low fruit and vegetable consumption accounted for 56.9% (95% CI = 36.6% to 75.1%), 72.4% (95% CI = 53.3% to 85.8%), and 28.7% (95% CI = 11.1% to 56.5%) of esophageal squamous cell carcinomas, respectively, with a combined PAR of 89.4% (95% CI = 79.1% to 95.0%). Ever smoking, history of gastric ulcers, nitrite intake above the lowest quartile, and H. pylori infection were responsible for 18.3% (95% CI = 6.5% to 41.8%), 9.7% (95% CI = 5.4% to 16.8%), 40.7% (95% CI = 23.4% to 60.7%), and 10.4% (95% CI = 0.3% to 79.6%) of noncardia gastric adenocarcinomas, respectively, with a combined PAR of 59.0% (95% CI = 16.2% to 91.4%).

CONCLUSION

In this population, a few known risk factors account for a majority of esophageal and gastric cancers. These results suggest that the incidence of these cancers may be decreased by reducing the prevalence of smoking, gastroesophageal reflux, and being overweight and by increasing the consumption of fruits and vegetables.

Spontaneous disappearance of Helicobacter pylori antibodies in patients with advanced atrophic corpus gastritis

Background. Only a few reported studies focus on the natural history and course of advanced and severe chronic atrophic gastritis. Methods. In this study we followed 47 men (mean age 62 years) with advanced (moderate or severe) Helicobacter pylori-positive atrophic corpus gastritis. Duration of endoscopic follow-up was 6 years and follow-up based on serum levels of pepsinogen I and antibodies to H. pylori covered a period of 10 years. None of the patients was treated for H. pylori infection prior to end of follow-up. Results. The median H. pylori antibody titre declined (IgG from 4000 to 1300; IgA from 200 to 50) in the study population, and 11 men (23%) converted to seronegative (p=0.0005, Fisher's exact test). There was a small but significant (p=0.0004, Page's test) declining trend in mean atrophy score of the corpus during follow-up (from 2.5 to 2.2). However, no significant changes were observed in grade of atrophy or intestinal metaplasia of the antral mucosa or in grade of intestinal metaplasia in the corpus. The mean SPGI level remained at the initial low level during the entire follow-up. Conclusions. H. pylori antibodies disappear spontaneously within 10 years in almost one fourth of patients with advanced atrophic corpus gastritis. The disappearance of H. pylori antibodies is accompanied by no or more than a mild improvement of the gastric mucosa.

Culturing Helicobacter pylori from clinical specimens: review of microbiologic methods

Helicobacter pylori is probably the most common chronic bacterial infection of humankind, and is usually acquired first in childhood. Microbiologic culture of H. pylori is the "gold standard" for diagnosis in a patient with suspected infection. Although not currently recommended for routine use, culture allows testing for susceptibility to antimicrobials, especially in populations with a high prevalence of drug resistance. Gastric biopsies are the specimens most commonly used to culture H. pylori, but stool, vomitus, saliva, and dental plaque offer opportunities. This review examines the current methods used to culture H. pylori from biologic specimens and suggests useful hints to enhance its recovery rate.

An association between Helicobacter pylori infection and serum vitamin B12 levels in healthy adults

GOALS

To determine whether serum vitamin B12 levels in non-vitamin B12 deficient healthy adults correlate with serological evidence of H. pylori infection.

BACKGROUND

An association between H. pylori infection and vitamin B12 deficiency has been recently reported.

STUDY

133 adults, presenting to a community based primary care clinic who met the following exclusion criteria; history of H. pylori eradication or antacid use, liver disease, inflammatory bowel disease, previous gastrointestinal surgery, a vegetarian diet or multivitamin supplementation were studied. Blood was drawn for a complete blood count, serum vitamin B12, gastrin, folic acid and H. pylori IgG antibodies. Subjects with vitamin B12 < or = 145 ng/mL (deficient range) were excluded.

RESULTS

Of 133 subjects 96 (72.2%) were seropositive for H. pylori IgG antibodies (HP+). Age of HP(+) subjects did not differ from that of seronegative subjects (HP-); 52.8 +/- 1.6 mean +/- SE versus 49.2 +/- 2.9 ( = NS). Prevalence of HP seropositivity was significantly higher among subjects with borderline (>145-180 pg/mL) or low normal (>180-250 pg/mL) vitamin B12 levels than among those with vitamin B12 > 250 pg/mL; among 25 subjects with vitamin B12 > 145-180 pg/mL 92% were seropositive and among 47 subjects with vitamin B12 > 180-250 pg/mL 89% were seropositive as compared with 31/61 (51%) of subjects with B12 > 250 pg/mL, Fisher exact test < 0.0001. Vitamin B12 levels did not correlate with age (r = -0.07). Gastrin levels (pg/mL) did not differ significantly between groups; 70.2 +/- 5.8 in HP(+) versus 56.0 +/- 12.4 in HP(-).

CONCLUSIONS

The higher prevalence of H. pylori infection among subjects with serum vitamin B12 levels that are within the lower end of the normal range suggests a causal relationship between H pylori infection and vitamin B12 levels in healthy adults.