Diagnostic value of decreasing IgG, IgA, and IgM antibody titres after eradication of Helicobacter pylori

Persisting chronic gastritis and elevated Helicobacter pylori antibodies after successful eradication therapy

AIM

The persistence of chronic inflammation in gastric mucosa and elevated Helicobacter pylori antibodies after successful eradication therapy are common findings in clinical practice. We studied their possible association with each other and disappearance in long-term follow up, as well as their possible connection with gastric atrophy.

PATIENTS AND METHODS

The study population consisted of 108 dyspeptic patients with successful eradication therapy median 6.4 years earlier. The patients underwent gastroscopy, and biopsies from antrum and corpus were evaluated by an experienced pathologist. Serum samples collected from 77 patients were studied for H. pylori antibodies, parietal cell antibodies, as well as for pepsinogen I, pepsinogen II, and gastrin-17 levels.

RESULTS

The prevalence of chronic gastric inflammation and elevated H. pylori antibodies after successful eradication therapy decreased by time, but still after 5 years, 17 of 51 (33%) subjects had elevated H. pylori antibodies and 14 of 68 (21%) had a mild inactive chronic inflammation in gastric mucosa. In patients with and without chronic inflammation in gastric mucosa, elevated H. pylori antibodies were detected in three of 10 (30%) and 14 of 41 (34%), elevated parietal cell antibodies in one of 10 (10%) and six of 41 (15%), low pepsinogen I in one of 10 (10%) and none of 41, and elevated gastrin-17 in three of 10 (30%) and six of 41 (15%), respectively.

CONCLUSION

More than 5 years after successful H. pylori eradication therapy, mild persistent chronic inflammation may occur in gastric mucosa in up to one-fifth and elevated H. pylori antibodies even in one-third of patients, although these two are independent phenomena.

Current management of Helicobacter pylori infections in the elderly

Helicobacter pylori infection is a chronic gastric gram-negative infection that increases with age worldwide. However, the percentage age of H. pylori-positive elderly patients who are tested and treated for their infection remains very low. It is now demonstrated that H. pylori infection induces a whole cascade of events leading to gastric pathologies, such as peptic ulcer diseases, gastric precancerous lesions and gastric cancer. Recent data also demonstrated that H. pylori chronic infection can play a role in gastric aging, appetite regulation and extradigestive diseases, such as Alzheimer's disease, in the elderly. The diagnosis of H. pylori infection remains difficult to realize in the very old population, and the urea breath test obtains the best performance in this population. 1-week proton pump inhibitor-based triple therapy regimens are highly effective and well tolerated in elderly patients, and antibiotic resistance remains very low. Low compliance is the main factor related to treatment failure in this population.

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.

Size of the peptic ulcer in Helicobacter pylori-positive patients: association with the clinical and histological characteristics

OBJECTIVE

Based on a large trial of Helicobacter pylori-positive peptic ulcer patients, we studied whether the size of the ulcer, along with other clinical and histological characteristics, has any effect on healing. We also studied the clinical and endoscopic characteristics associated with size of the peptic ulcer.

MATERIAL AND METHODS

A total of 333 consecutive patients with H. pylori infection and peptic ulcer were enrolled (mean age 54.8+/-12.7 years). Location of the ulcer was recorded by gastroscopy and the presence of H. pylori was assured by rapid urease test, histology and by serum H. pylori IgG and IgA antibody measurement. The diameter of the ulcer was measured by placing the opened biopsy forceps (7 mm) beside it. Biopsy specimens were examined in accordance with the Sydney system.

RESULTS

Mean size of the peptic ulcer was 13.2+/-8.3 in corpus, 11.3+/-5.3 in antrum, 13.8+/-7.8 in angulus, 9.5+/-5.3 in prepylorus and 9.2+/-4.7 mm in duodenum (duodenal versus gastric type; p<0.05). Average size of the ulcers was 9.4+/-5.3 mm in patients with Forrest III type and 11.5+/-6.8 in other types (p<0.05). Patients who were >or=50 years of age, currently smoking, or who had corpus-predominant chronic gastritis or atrophic gastritis, had larger ulcers than others. Size of index ulcers, successful eradication of H. pylori and the presence of atrophic gastritis were independent factors for healing. The odds ratio was 11.5 (95% CI 3.3-40.5; p<0.01) for eradication of H. pylori, 3.5 (95% CI 1.1-11.2; p<0.05) for size of the index ulcer (<or=10 mm versus >10 mm) and 3.4 (95% CI 1.2-9.8; p<0.05) for atrophic gastritis versus no atrophy.

CONCLUSIONS

Size of the peptic ulcer, successful H. pylori eradication and atrophic gastritis were independent factors for the healing of peptic ulcers. A number of clinical and endoscopic variables (age, current smoking, corpus-predominant gastritis, Forrest classification) were associated with size of the peptic ulcer in H. pylori-positive patients.

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.

Non-Invasive Serological Detection of Helicobacter pylori Antigens in Adult Hong Kong Chinese Non-Ulcer Dyspepsia Patients

OBJECTIVE

The aim of our study was to evaluate the accuracy of the serology test kit (Signify H. pylori test), an office-based serological test and to compare relative performances with endoscopy, including biopsy urease tests (Clotest), histology, and culture when applied to dyspeptic adult patients in Hong Kong Chinese.

METHODS

Prospective clinical trial was conducted at the Alice Ho Miu ling Nethersole Hospital (AHNH) outpatient endoscopy center from June to December 2004 and included adult Chinese patients who attended the endoscopy center. A research nurse interviewed consenting patients and whole blood samples were obtained via simple fingerstick were then and transferred to Signify test kits. The results were read after 5 minutes. The presence of two distinct lines within the result-reading window was treated as a positive result; a single distinct line was treated as a negative result. All patients underwent upper gastroduodenal endoscopy, and antral/antrum gastric biopsy specimens were taken and then processed for microbiological cultures.

RESULTS

A total of 384 patients were recruited in the study and 131 (34.7%) patients were tested positive for H. pylori. Among them, 62 patients (47.3%) were detected by the Signify H. pylori test. The Signify serology test kit was 52.7% sensitive, 87.9% specific, and 75.7% accurate, respectively in the current study.

CONCLUSION

The Signify H. pylori test showed a sub-optimal correlation between the presence of H. pylori infection and the serological test results in a Hong Kong Chinese population.

Helicobacter pylori IgA and IgG antibodies, serum pepsinogen I and the risk of gastric cancer: changes in the risk with extended follow-up period

The prediction of Helicobacter pylori antibodies immunoglobulin A (IgA) and immunoglobulin G (IgG) and serum pepsinogen I (PG I) on gastric cancer occurrence was studied in a nested case-control study, based on 225 incident cancer cases and 435 matched controls from a Finnish cohort followed from 1966-1991. The odds ratio of noncardia gastric cancer between infected and noninfected persons was 3.12 (95% confidence interval (CI)=1.97-4.95) for elevated IgA and 2.88 (CI: 1.63-5.07) for elevated IgG antibodies. The odds ratio between low and high PG I was 2.24 (CI: 1.43-3.49). The strength of association was significant for IgA antibodies during the total follow-up, but for IgG antibodies this was only true for follow-up periods of 15 years or more. IgA antibodies were significantly associated with all registered histological subtypes apart from intestinal type adenocarcinoma. The highest gastric cancer risk was found among individuals with simultaneously elevated IgA and IgG antibodies and low PG I with an odds ratio of 10.9 (CI: 4.31-27.7) in comparison with those who were negative for both antibodies and had normal PG I. Elevated IgA and IgG antibodies and low PG I were not associated with cancers of the gastric cardia. The findings support the hypothesis that H. pylori infection is a cause of noncardia gastric cancer. Although elevated H. pylori IgA and IgG antibodies and low PG I independently could predict the occurrence of noncardia gastric cancer, their power to do so varied with the stage and length of the follow-up period and it increased when they were applied in combination.

Clinical significance of widespread gastric metaplasia in the duodenal bulb

BACKGROUND

All the risk factors of peptic ulcer disease are not thoroughly understood.

GOALS

To assess duodenal gastric metaplasia (DGM) in relation to Helicobacter pylori status and endoscopy findings with special reference to the effects of highly selective vagotomy.

STUDY

The study population consisted of 1056 adult patients and an additional 154 patients who had had a highly selective vagotomy. Their clinical and endoscopy records as well as the histology of gastric and duodenal biopsies were evaluated retrospectively. H. pylori infection had been determined by serology and culture.

RESULTS

Widespread (more than 20%) DGM was strongly associated with H. pylori positive duodenal ulcer disease (in 59.7% of patients). The prevalence of DGM diminished progressively the more proximally the ulcer was located in the stomach, and was 2.5% in proximal gastric ulcers patients. In vagotomized patients, the prevalence of widespread DGM (8.4% of patients, median 14 years after operation and the majority still H. pylori positive) was close to that of patients with H. pylori gastritis without peptic ulcer disease (4.5%).

CONCLUSIONS

Widespread DGM is an indicator for an increased risk of duodenal ulcer among H. pylori positive patients and it could be used to select patients for eradication therapy.

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.

IgA antibodies in persisting Helicobacter pylori infection in Finnish adults

Most individuals infected with Helicobacter pylori have elevated levels of specific IgG antibodies, but only in about two-thirds of cases does the IgA titre exceed the cut-off level. The aim of this study was to determine whether H. pylori-infected subjects with elevated IgG levels would subsequently produce IgA antibodies, and whether elevated IgA levels increased during infection. Paired sera were available from 336 adults who took part in a large population-based health survey in 1977-1980 and a follow-up study on asthma and atopic diseases in 1997-1998 (series A). Data on paired sera from 224 adults who participated in a population-based health survey in Vammala, Finland in 1973 and who gave a follow-up blood sample in 1994 (series B) were also re-analysed. H. pylori IgG and IgA levels were determined with commercially available (series A) and in-house (series B) enzyme immunoassays. Twenty-one (35%) of the 60 subjects who initially had elevated levels of IgG antibodies only were found to be IgA-positive at follow-up. In those subjects whose baseline and follow-up samples were IgG- and IgA-positive, the median IgA levels increased by 48% and 22% in series A and B (p < 0.0001 and p 0.0241), respectively, whereas the median IgG levels did not change significantly in either series. During H. pylori infection, an increase in specific IgA was reflected by the increase in the number of responders and by the rise in titres.

Association of Helicobacter pylori IgA antibodies with the risk of peptic ulcer disease and gastric cancer

AIM

To compare the prevalence of Helicobacter pylori (H pylori) IgG and IgA antibodies between adult subjects, with defined gastric diseases, non-defined gastric disorders and those representing the population.

METHODS

Data on H pylori IgG and IgA antibodies, determined by enzyme immunoassay, were analyzed in 3,252 subjects with DGD including 482 patients with gastric ulcer, 882 patients with duodenal ulcer, 1,525 patients with chronic gastritis only and 363 subjects with subsequent gastric cancer, 19,145 patients with NoDg and 4,854 POPUL subjects. The age-adjusted prevalences were calculated for 1- and 20-year age cohorts.

RESULTS

The prevalences of IgG antibodies were equally high (89-96%) in all 20-year age cohorts of the DGD groups, whereas the prevalences of IgG antibodies were lower and increased by age in the POPUL and NoDg groups. The prevalences of IgA antibodies were also higher in the DGD groups; among them CA (84-89%) and GU groups (78-91%) showed significantly higher prevalences than DU (68-77%) and CG patients (59-74%) (OR 2.49, 95%CI 1.86-3.34 between the GU and DU groups). In the CA, GU, and DU groups, the IgA prevalences showed only minor variation according to age, while they increased by age in the CG, POPUL, and NoDg groups (P<=0.0001). The IgA response, but not the IgG response, was associated with an increased risk of CA (OR 2.41, 95%CI 1.79-3.53) and GU (OR 2.57, 95%CI 1.95-3.39) in comparison with CG patients.

CONCLUSION

An IgA antibody response during H pylori infection is significantly more common in CA and GU patients as compared with CG patients.

Helicobacter pylori infection and typhoid fever in Jakarta, Indonesia

We evaluated the association between typhoid fever and Helicobacter pylori infection, as the latter microorganism may influence gastric acid secretion and consequently increase susceptibility to Salmonella typhi infection. Anti-H. pylori IgG and IgA antibody titres (ELISA) and gastrin concentration (RIA) were determined in the plasma of 87 blood culture-confirmed typhoid fever cases (collected after clinical recovery) and 232 random healthy controls without a history of typhoid fever, in the Jatinegara district, Jakarta. Patients with typhoid fever more often than controls were seropositive for H. pylori IgG (67% vs. 50%, P<0.008), when antibody titres were dichotomized around median titres observed in controls. H. pylori IgA seropositivity was not associated with typhoid fever. Plasma gastrin concentrations indicative of hypochlorhydria (i.e. gastrin > or =25 or > or =100 ng/l) were not significantly elevated in typhoid fever cases compared to controls (P=0.54 and P=0.27 respectively). In a multivariate analysis, typhoid fever was independently associated with young age (<33 years, median age of the controls) [odds ratio (OR) 7.93, 95% confidence interval (CI) 3.90-16.10], and H. pylori IgG seropositivity (OR 1.93, 95% CI 1.10-3.40). Typhoid fever was independently associated with H. pylori IgG seropositivity, but not with elevated gastrin concentration. Therefore, the association suggests a common risk of environmental exposure to both bacteria, e.g. poor hygiene, rather than a causal relationship via reduced gastric acid production.

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.

Prevalence of Helicobacter pylori in United States Navy submarine crews

Helicobacter pylori prevalence is elevated in German submarine crews and in United States Navy (USN) surface fleet personnel, but H. pylori prevalence in USN submariners was unknown. The goal of the study was to determine the prevalence of H. pylori in the crews of USN nuclear submarines compared to other military personnel and to the general US population. The presence of H. pylori IgG antibodies was determined in serum samples using a commercial ELISA. Only 47 out of 451 submariners (9.4%) were H. pylori positive, which is similar to that of the US general population with a similar level of education. In contrast, H. pylori prevalence is significantly higher in US Army recruits (26%), USN surface fleet personnel (25%), and German diesel submariners (38%). These data demonstrate that submarine service (and by inference activity requiring isolation and close contact, per se) is not a risk factor for H. pylori infection.

An observational study of upper gastrointestinal bleeding in intensive care units: is Helicobacter pylori the culprit?

OBJECTIVE

Upper gastrointestinal bleeding (UGIB) related to stress ulcers was formerly a fearsome complication of intensive care. The incidence of this event has decreased over the years. However, the morbidity, mortality, and causes of UGIB, particularly the etiologic role of Helicobacter pylori infection, are still controversial. Therefore, we prospectively assessed the incidence of UGIB in the intensive care unit (ICU) and evaluated the role of H. pylori infection.

DESIGN

A prospective observational study followed by a case-control study.

SETTING

Seven ICUs in the Paris area, five of them located in teaching hospitals.

PATIENTS

All patients admitted consecutively to seven ICUs during a 1-year period were monitored for signs of clinically relevant UGIB.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Only cases of endoscopically confirmed UGIB were analyzed. Patients whose hemorrhage originated from the stomach and/or duodenum were tested for H. pylori infection, by means of serology, histologic examination, and stool antigen detection. The possible association between H. pylori and UGIB was examined in a case-control study. Twenty-nine of the 4,341 patients admitted to the seven ICUs during the study period had clinically relevant, endoscopically confirmed UGIB (incidence, 0.67%; 95% confidence interval, 0.56%-0.77%). Ulcers were most frequently observed endoscopically. Patients who bled had a higher Simplified Acute Physiology Score (SAPS II) at admission (mean +/- sd, 47 +/- 14 vs. 36 +/- 28; p < .001). Despite a higher in-ICU mortality rate among patients who bled (73% vs. 16%; p < .001), death was never due to bleeding. H. pylori infection was more frequent in patients who bled than in matched controls (36% vs. 16%; p = .04).

CONCLUSIONS

Clinically relevant, endoscopically confirmed UGIB is a rare event in the ICU setting and tends to occur in severely ill patients. H. pylori infection is more frequent in patients with gastroduodenal hemorrhage than in nonbleeding patients.

Helicobacter pylori infection and platelet counts during pregnancy

OBJECTIVE

To investigate whether there is any correlation between Helicobacter pylori infection and platelet counts during pregnancy.

METHODS

One hundred and twenty pregnant women without any complications were evaluated. Platelet counts were determined during pregnancy and postpartum. H. pylori infection was assessed by the detection of serum antibodies at the 3rd day postpartum. Statistically significant differences of platelet count between H. pylori-positive and -negative patients were determined.

RESULTS

H. pylori infection was found in 29 of 120 (24.2%). Platelet counts in the 3rd trimester were 22.7+/-4.7 x 10(3)/microl in H. pylori-positive group and 22.8+/-5.6 x 10(3)/microl in negative group (p=0.98). Platelet count in the 3rd trimester in positive and negative patients were 93+/-17% and 94+/-20%, respectively, of that of the 1st trimester (p=0.92). The incidence of hyperemesis gravidarum in both groups was not significant (p=0.28).

CONCLUSION

A correlation between H. pylori infection and thrombocytopenia during pregnancy was not found in this study.

Diagnosis and genotyping of Helicobacter pylori by polymerase chain reaction of bacterial DNA from gastric juice

BACKGROUND

Efficient and accurate detection of Helicobacter pylori infection as well as identification of virulence-associated alleles are important for the treatment of gastroduodenal diseases caused by this gastric pathogen. The present study was performed to test the efficiency of gastric juice polymerase chain reaction (PCR) method for the rapid detection of H. pylori infection and to determine the bacterial genotypes without the need for culture, which is often not feasible especially in developing countries.

METHODS

DNA was extracted from gastric juice samples collected from 45 subjects and was used to amplify urease B gene (ureB) for H. pylori. Results obtained from this method were further confirmed by rapid urease test (RUT), histology and culture. Genotypes of the infected strains predicted from gastric juice PCR were compared to the genotype data obtained from the isolated strains.

RESULTS

Among 45 cases, 32 were positive by RUT, 37 by histological examination, 25 by gastric juice PCR method, while culture yielded positive results for 19 samples. Except for one case, all the 19 culture-positive strains gave the same genotype with the gastric juice PCR result. It was found that the gastric juice PCR is more efficient for detection of multiple-strain infection as compared to genotype data obtained from strains isolated as pooled culture.

CONCLUSIONS

This moderately sensitive technique could be employed with good efficiency, particularly in cases where it is difficult to obtain biopsy. Moreover, with this method bacterial genotype could be obtained.

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.

First-line eradication therapy for Helicobacter pylori in primary health care based on antibiotic resistance: results of three eradication regimens

AIM

To determine the efficacy of three Helicobacter pylori eradication regimens and factors affecting the eradication results in Finland.

METHODS

A total of 342 H. pylori-positive adult patients from primary health care referred for gastroscopy at 23 centres in different parts of Finland were randomized to receive either (i) lansoprazole 30 mg b.d., amoxicillin 1 g b.d. and metronidazole 400 mg t.d.s. (LAM), (ii) lansoprazole 30 mg b.d., amoxicillin 1 g b.d. and clarithromycin 500 mg b.d. (LAC), or (iii) ranitidine bismuth citrate 400 mg b.d., metronidazole 400 mg t.d.s. and tetracycline 500 mg q.d.s. (RMT). A (13)C-urea breath test was performed 4 weeks after therapy.

RESULTS

The eradication result could be assessed in 329 cases. Intention-to-treat cure rates of LAM, LAC, and RMT were 78, 91 and 81%. The difference was significant between LAM and LAC (P = 0.01) and between LAC and RMT (P = 0.04). The eradication rates in cases with metronidazole-susceptible vs. -resistant isolates were for LAM 93% vs. 53% (P = 0.00001), for LAC 95% vs. 84%, and for RMT 91% vs. 67% (P = 0.002). Previous antibiotic use, smoking, and coffee drinking reduced the efficacy of therapy.

CONCLUSIONS

In unselected patients in primary health care, LAC was the most effective first-line eradication.

Sjogren’s syndrome: concomitant H. Pylori infection and possible correlation with clinical parameters

OBJECTIVE

To identify whether or not there are clinical markers that correlate with Helicobacter pylori (H. pylori) infection in patients with Sjogren's syndrome (SS) and its implication to handling this group of patients.

METHODS

Four groups of patients were studied. Group 1, 36 patients with primary SS; group 2, 31 patients with secondary SS; group 3, 46 patients with various connective tissue diseases not suffering from sicca symptoms, and group 4, 64 healthy controls. Clinical assessment was done and a score for disease manifestation was given for every SS patient. Serum IgG and IgM antibodies to H. pylori were assessed by ELISA.

RESULTS

The prevalence and mean titer of H. pylori infection in patients with SS in group 1 (80.6%) and 2 (71%) were significantly higher than in group 3 (60.9%) and 4 (56.3%) (P < 0.01). There was significant correlation between H. pylori infection and age, disease duration, global score for disease status and C-reactive protein (CRP) in SS patients. On the other hand, there was no significant correlation with body mass index, and erythrocyte sedimentation rate (ESR).

CONCLUSION

Patients with SS are more prone to have H. pylori infection in comparison to other connective tissue diseases. Serum antibody titer to H. pylori correlated with index for clinical disease manifestations, age, disease duration and CRP. Assessment of H. pylori infection in older patients suffering from active SS for a relatively long duration is recommended, especially those suffering form primary SS for more than 3 years.

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.

Comparison of different criteria for interpretation of immunoglobulin G immunoblotting results for diagnosis of Helicobacter pylori infection

Gastric infection with Helicobacter pylori is one of the most common chronic infections in humans, causing substantial morbidity and mortality. The diagnosis of H. pylori infection usually involves upper endoscopy with biopsy since the only noninvasive method of comparable accuracy, the [(13)C]urea breath test, requires technical equipment that is not available in most gastroenterological units. Serological methods for detection of H. pylori infection have reached sufficient accuracy to be used as screening tests before endoscopy or for seroepidemiological surveys. In the present study we evaluated different interpretation criteria for use with immunoglobulin G immunoblotting for the diagnosis of H. pylori infection. We applied five different sets of interpretation criteria, four of which had been published previously, to the Western blot results of 294 patients with different gastrointestinal symptoms. Since it is known that less than 2% of patients who are infected with H. pylori fail to seroconvert, an optimally sensitive Western blotting system should be able to detect approximately 98% of active infections. When the different criteria were applied to our patient population, it became apparent that the abilities of the systems to detect active H. pylori infection were quite varied. The results for the sensitivity and specificity, according to the different applied criteria, ranged from 62.8 to 95.9% and from 85.7 to 100.0%, respectively. Positive predictive values and negative predictive values, according to the published criteria, ranged from 97.2 to 100.0% and from 37.7 to 82.4%, respectively. Recommendations for the optimal use of the different interpretation criteria are discussed.

Helicobacter pylori eradication as the sole treatment for gastric and duodenal ulcers

OBJECTIVES

It is uncertain whether eradication of Helicobacter pylori--without a prolonged suppression of acid secretion--is sufficient to allow healing of peptic ulcers. We evaluated whether eradication of H. pylori with no following anti-secretory medication then administered is sufficient for treatment of peptic ulcers. We also looked at the impact of non-steroidal anti-inflammatory drug (NSAID) and acetylsalicylic acid (ASA) use on ulcer relapses.

METHODS

The effect of eradication on ulcer healing and relapse rate was analysed in 115 patients, randomly allocated to four treatment groups: (1) quadruple therapy (28); (2) dual therapy (n-30); (3) triple therapy (n=27); and (4) lansoprazole and placebo (n=30). Endoscopic assessment was performed at 0, 8, and 52 weeks.

RESULTS

The ulcer healing rate was 100% [95% confidence interval (CI), 95-100%] in H. pylori-negative and 83% (95% CI, 67-94%) in H. pylori-positive patients (P<0.01). In patients who used NSAIDS or ASA, the healing rates was 100% (95% CI, 73-100%) and 75% (95% CI, 19-99%) in H. pylori-negative (12 patients) and H. pylori-positive patients (four patients) (P = not significant). Ulcer relapses occurred in 5% (95% CI, 1-13%) of H. pylori-negative and in 36% (95% CI, 19-56%) of H. pylori-positive patients (P < 0.01). In H. pylori-negative patients who used NSAIDs or ASA the ulcer relapse rate was 30% (95% CI, 7-65%), whereas the ulcer relapse rate was 2% (95% CI, 0.4-10%) in patients who did not use NSAIDs or ASA (P < 0.05). No difference in ulcer relapse rate in H. pylori-positive patients who used or did not use NSAIDs or ASA was found. The eradication rate of H. pylori was 93% (95% CI, 76-99%) in the quadruple therapy group, 83% (95% CI, 64-94%) in the dual therapy group, 100% (95% CI, 87-100%) in the triple therapy group, and 0% (95% CI, 0-12%) in the lansoprazole and placebo group.

CONCLUSIONS

Eradication treatment for H. pylori-positive gastric or duodenal ulcer is sufficient, with no need to follow it with anti-secretory medication. Cure of the infection reduces ulcer relapses in patients who did not use NSAIDs or ASA.

Seropositivity for Helicobacter pylori antibodies is associated with lower occurrence of venous bypass graft occlusion

Common chronic infections including those caused by cytomegalovirus (CMV), herpes simplex viruses (HSV), Helicobacter pylori and Chlamydia pneumoniae have previously been related to increased risk of coronary heart disease (CHD). We investigated the association between serology of these chronic infections and coronary bypass graft occlusions in 61 patients. As a result, IgG seropositivity rate against H. pylori was higher among patients without occlusion (82%) than in those with occlusion (45%) or apparently healthy controls (57%) (p = 0.004 and p = 0.008, respectively). In conclusion, H. pylori infection, as judged by IgG seropositivity, is associated with lower occurrence of venous bypass graft occlusion in patients with CHD and may thus be connected with better outcome and prognosis of CHD patients after bypass graft surgery.

Comparison of serum IgA and IgG antibodies for detecting Helicobacter pylori infection

OBJECTIVE

Although the diagnostic utility of serum IgG antibodies to Helicobacter pylori (H. pylori) is well established, the usefulness of IgA-based tests is less well documented. The aim of this study was to evaluate two commercially available ELISAs, both for IgG and IgA.

PATIENTS AND METHODS

Rapid urease test and histology analysis were performed in 183 patients. A patient was considered to be H. pylori-positive when either biopsy test was positive, and considered to be noninfected when both tests were negative. Intestinal metaplasia was determined by dye endoscopy with methylene blue. ELISA testing was performed using the EPI HM-CAP IgG and PP-CAP IgA assays and EIAgen IgG and IgA assays.

RESULTS

Sensitivity was 94.7, 93.9, 94.8, and 97.0% for HM-CAP IgG, PP-CAP IgA, EIAgen IgG, and EIAgen IgA, respectively. Although sensitivity was excellent for both IgG and IgA antibodies, specificity of both IgA EIAs was low (PP-CAP 72.6%, EIAgen H. pylori IgA 59.2%). Three of 101 H. pylori-infected patients were PP-CAP positive and HM-CAP negative and four were EIAgen H. pylori IgA positive and EIAgen IgG negative. Of eight noninfected patients in whom intestinal metaplasia was found, PP-CAP IgA results were positive in three of five patients with a HM-CAP IgG negative result and EIAgen IgA was detected in one of four patients with an EIAgen IgG negative result.

CONCLUSIONS

Since some patients have IgA positive but IgG negative results, great care should be taken not to underestimate the prevalence of H. pylori infection from the results of IgG serology.

Accelerated decline in Helicobacter pylori seroprevalence rate during the screen and treat project in Vammala, Finland, as demonstrated in 29- to 45-year-old pregnant women

The potential preventability of serious helicobacter-associated diseases - especially gastric cancer - has evoked interest in eradicating this pathogen from the population. We assessed the efficacy of the pioneering screen and treat intervention project in Vammala by studying helicobacter seroprevalence in pregnant women representing the normal population. Consecutive maternity clinic samples from native Finnish females at five different localities in 1995 (n=701) and 2000 (n=772) were investigated for class IgG H. pylori antibodies by enzyme immunoassay (Pyloriset EIA-G III, Orion Diagnostica, Espoo, Finland). In Vammala the change in helicobacter seroprevalence was -13%-units (between 1995 and 2000; p=0.0125, chi-square test) in > or =29-year-old females, +1.6%-units (difference statistically non-significant) in <29-year-old females, and -5.5%-units (difference statistically non-significant) in the whole study population. In the four reference localities studied, all the corresponding changes remained statistically non-significant. Thus, in Vammala the programme applied accelerated the decline of helicobacter infections in 29- to 45-year-old females and in 2000 the seroprevalence rate had also become significantly lower than that of the four reference communities combined (7.6% versus 13.5%, respectively, p=0.0433, chi-square test). The final outcome of the intervention project, i.e. the long-term effect of this decline on gastric cancer and peptic ulcer disease, remains to be evaluated.

Non-invasive diagnosis of Helicobacter pylori infection: simplified 13C-urea breath test, stool antigen testing, or DNA PCR in human feces in a clinical laboratory setting?

OBJECTIVES

(1) To compare two stool antigen EIAs (HpSA, FemtoLab) and PCR of ureaseA and cagA in feces, with (13)C-urea breath test (UBT). (2) To ascertain whether a simplified UBT (breath collection time = 10 min) is as reliable as the standard assay (30 min).

DESIGN AND METHODS

Helicobacter pylori status was recorded in Group 1 (n = 187) by UBT, H. pylori stool antigen, ureA and cagA PCR in feces. UBT with 10, 20 and 30 min sampling was performed in Group 2 patients (n = 283).

RESULTS

The sensitivity and specificity of HpSA, FemtoLab, and ureA were 67% and 99%, 90% and 96%, 35% and 98%, respectively. cagA results were positive in 16/48 H. pylori-positive, and in 5/100 H. pylori-negative patients. The results of UBT with a 10- and 30-min sampling strictly overlapped.

CONCLUSION

UBT with 10 min breath collection and FemtoLab stool antigen assay are the most reliable non-invasive tests to diagnose H. pylori infection.

Are tonsils a reservoir for Helicobacter pylori infection in children?

OBJECTIVE

Helicobacter pylori (H. Pylori) has been associated with the development of gastritis, peptic ulcer and gastric cancer. Although H. pylori infects up to more than half of the world's population, to date the precise modes of transmission has not been fully understood yet. Therefore a study was planned to investigate whether the tonsils and the adenoid tissue were the reservoir or the gate for the entrance of H. pylori.

METHODS

The adenotonsillectomy specimens obtained from 50 children, between two and 10 years of age were examined for H. Pylori colonization by the CLO-test method. Before tonsillectomy, anti-H. pylori IgG antibody titers were detected by commercial enzyme immunoassay method in venous blood and H. pylori antigen enzyme immunoassay for detection of H. pylori in stool was used to define current infection status.

RESULTS

The stool antigen was positive in 25 (50%) of 50 children. Serum IgG antibody was positive in 28 (56%) patients and both tests were positive in 21 (42%) patients. H. pylori positivity was not detected in any one of the adenotonsillectomy specimens with the CLO-test method.

CONCLUSION

In this study although H. pylori was detected in stools of children, it was not detected in adenotonsillectomy specimens with CLO-test method. The results may indicate that H. pylori does not colonize in either adenoid or tonsils and that these tissues do not constitute a reservoir for H. pylori infection.

Helicobacter pylori infection in Finland

Helicobacter pylori causes chronic gastritis worldwide and it is the most important single factor in peptic ulcer disease. Up to half of H. pylori infected individuals develop atrophic gastritis over years and decades. H. pylori infection has also been classified as a class I carcinogen in human gastric cancer. Most infections are obtained in childhood, in Finland mainly before the age of 7 years but the exact transmission routes are not known. The infection shows an age-dependent pattern, the infection being rare among children but gradually becoming more prevalent among older age groups. As new infections are few in adults and the infection only rarely disappears without effective anti-microbial therapy, the occurrence of the infection in the old actually reflects the prevalence of the infection in their childhood. In developed countries, such as Finland, a rapid decline of H. pylori prevalence rate has been demonstrated. In order to speed up this natural decline of the infection, a unique population based 'screen and treat' project was started in Vammala, a semiurban south-western community in Finland. In this survey, young inhabitants were offered diagnosis and treatment for H. pylori.

Development of Barrett's esophagus after 'spontaneous' healing of atrophic corpus gastritis

We report here the case of a 58-year-old asymptomatic male smoker who had a gastroscopy performed in 1990 because of a low serum pepsinogen I level (16 microg/l). The patient had severe atrophic corpus gastritis and elevated Helicobacter pylori antibody titers, but no histologic evidence of the bacteria. Additionally, a hiatal hernia without esophagitis was seen. He was followed up endoscopically because of the atypical changes (indefinite for dysplasia) in addition to atrophic gastritis in some of the gastric biopsy samples. During the follow-up period, H. pylori antibody titers declined to normal levels without eradication therapy, and atrophic gastritis healed. The patient developed first erosive esophagitis, and, 5 years later, a 3-cm-long Barrett's esophagus was detected.

Eradication of Helicobacter pylori improves the healing rate and reduces the relapse rate of nonbleeding ulcers in patients with bleeding peptic ulcer

OBJECTIVE

A causal relationship between Helicobacter pylori (H. pylori) and peptic ulcer complications remains obscure. The aim of this study was to determine the importance of H. pylori and other risk factors for healing rate, ulcer recurrence, and rebleeding in patients with bleeding peptic ulcer.

METHOD

A total of 223 patients with H. pylori positive bleeding peptic ulcer were randomly allocated to three treatment groups: 1) quadruple therapy (QT) (88 patients); 2) dual therapy (DT) (88 patients); and 3) omeprazole and placebo therapy (OPl) (47 patients). Endoscopic assessment was performed initially and at 8 and 52 wk. Ulcer healing and eradication rates were assessed; endpoints were ulcer relapse and ulcer rebleeding during 52 wk.

RESULTS

Results after 8 and 52 wk were available for 211 and 179 patients, respectively. Eradication rate was 100% (95% CI = 96-100%) in the QT, 84% (95% CI = 74-91%) in the DT, and 4% (95% CI = 1-15%) in the OPl group. Ulcer healing rate was 95% (95% CI = 91-98%) in H. pylori negative and 8% (95% CI = 70-91%) in H. pylori positive patients. Ulcer relapses occurred in 2% (95% CI = 0.5-6%) of H. pylori negative and in 38% (95% CI = 24-54%) of H. pylori positive patients, and rebleeding occurred in five patients (three H. pylori positive and two negative).

CONCLUSIONS

Eradication of H. pylori infection enhances healing of bleeding peptic ulcers after endoscopic therapy. H. pylori infection is an important independent risk factor for relapsing of nonbleeding ulcers in patients with bleeding peptic ulcer.

What is the role of serology in assessing Helicobacter pylori eradication?

AIM

To assess the decline in Helicobacter pylori antibodies after eradication of infection.

METHODS

The H. pylori status was determined at entry (D0) by culture and histology performed on antral biopsies and after eradication treatment at day 42 (day 42) and after 6 months (M6) by the 13C-urea breath test. The EIA kits used to determine the anti-H. pylori antibody titre were HM-CAP (immunoglobulin-G) and PP-CAP (immunoglobulin-A) kits (Enteric Products, Inc.) and Pyloriset EIA-G (Orion Diagnostica).

RESULTS

Ninety-three patients were included. For 82 patients who were successfully treated, no kit was sufficiently accurate at D42 to show eradication. The antibody titre decreased for HM-CAP, PP-CAP and Pyloriset EIA-G by a mean of 35.6%, 41.2% and 64.7% between D0 and M6, respectively. According to the cut-off values defined by the manufacturers, 8.5% (PP-CAP, Pyloriset EIA-G) and 9.7% (HM-CAP) of the patients became H. pylori negative at M6. Using a 25% decrease in antibody titre between D0 and M6 as a threshold for H. pylori eradication, specificity was 100% for HM-CAP, 89.9% for Pyloriset EIA-G and 100% for PP-CAP, whereas the sensitivity was 76.8%, 98.8% and 72%, respectively.

CONCLUSION

An antibody titre decrease of 25% at M6 was found to be accurate in confirming H. pylori eradication.

Helicobacter pylori: a microbiologist's view

Helicobacter pylori infection is known to cause a number of gastrointestinal diseases. From the standpoint of a microbiologist there are several important facets to this organism, which include the nature of the organism, it's diagnosis and the effectiveness of eradication therapy.

Helicobacter pylori in intensive care: why we should be interested

Helicobacter pylori is estimated to infect over 50% of the world's population, the majority of whom are asymptomatic. Although most research to date has focused on local gastroduodenal disease manifestations, the potential impact of H. pylori infection and the associated chronic active inflammation on systemic disease processes is now being explored. This review addresses three aspects of emerging importance regarding H. pylori in intensive care medicine: acute gastric stress ulceration, nosocomial infection, and the potential modulatory effect on the systemic stress response. The role of H. pylori in acute stress ulceration remains uncertain, but it is unlikely to have the same major aetiological role as in peptic ulcer disease. The pathogenesis of both acute stress ulceration and H. pylori gastritis suggest overlapping mechanisms of gastric mucosal damage and H. pylori may augment stress ulceration incidence and severity. Nosocomial infection of both staff and patients with H. pylori has been suggested by serological studies, and increased H. pylori infection has been reported in intensive care staff. This has significant short- and long-term health implications and also raises questions regarding the efficacy and implementation of routine infection control precautions in intensive care. Finally, H. pylori infection has been linked with the pathogenesis of many extra-intestinal diseases, but the evidence is weak and the relationship between H. pylori and systemic diseases remains controversial. However, the potential for H. pylori to modulate systemic disease processes, particularly the systemic stress response in critical illness, is both theoretically plausible and therapeutically tantalising and requires further investigation.

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.

Helicobacter pylori infection in the Australian community: current prevalence and lack of association with ABO blood groups

AIMS

To assess the current prevalence of Helicobacter pylori infection in an Australian urban population sample and to relate this to age, gender and ABO and Rhesus blood groups.

METHODS

We performed a prospective epidemiological survey of H. pylori serological status in 500 consecutive voluntary blood donors who presented for the purpose of blood donation at the central -Melbourne branch of the Australian Red Cross Blood Service, Victoria, Australia, and gave a Melbourne suburban home address.

RESULTS

The overall prevalence of specific anti-H. pylori IgG antibodies in this cohort was 32% (95% confidence interval = 28-36%) and H. pylori sero-positivity increased with age. The rate of H. pylori infection was not significantly different in men and women, with anti-H. pylori IgG anti-bodies detected in 35% (97/277) of men compared with 28% (63/233) of women (P = 0.12). Similarly, H. pylori serological status was not significantly different between subjects of different ABO (P = 0.18) or Rhesus blood groups (P = 0.55).

CONCLUSION

This study showed that, contrary to expectation, the updated prevalence of H. pylori seropositivity (32%) in this Melbourne sample is at least as high as that found in previous Australian studies over the past 19 years. Seropositivity increased with age, and was not related to gender, confirming the infection pattern seen in other developed nations. Despite epidemiological evidence of increased peptic ulcer disease in ABO blood group O subjects, and recent evidence that H. pylori adhesion to gastric epithelial cells is mediated by blood group epitopes, no significant association between blood groups and H. pylori serological status was detected.

The seroprevalence of Helicobacter pylori infection in patients with obstructive sleep apnoea: a preliminary study

We investigated the seroprevalence of Helicobacter pylori in patients with obstructive sleep apnoea. A prospective clinical study consisting of 19 patients, aged 23-72 years with confirmed obstructive sleep apnoea by overnight polysomnography, and 36 control subjects, aged 25-61 years with no history of obstructive sleep apnoea and gastroesophageal reflux complaints, was conducted. Titres of serum H. pylori IgG antibody were assayed by a serum enzyme-linked immunoabsorbant assay. The difference between the study and control groups was analysed by chi-squared test. Seventeen of the 19 patients (89.5%) were found to be H. pylori positive. However, 21 of the 36 control subjects (58.3%) were H. pylori positive. The seropositivity of H. pylori in obstructive sleep apnoea patients was found to be significantly higher than the control group (P = 0.017). The result of our study shows that there is a high association between H. pylori infection and obstructive sleep apnoea. This data may be important for future treatment strategies of the disease.

Helicobacter pylori serology at diagnosis and follow-up of biopsy-verified infection in children

Data on the use of Helicobacter pylori serology in children are limited. We studied the serum antibodies of 105 H. pylori-infected children (median age 9.1 y, range 1.5-17.5 y) using an in-house enzyme immunoassay. At diagnosis of the biopsy-verified infection, IgG antibodies to H. pylori were elevated in 98/105 children (93%) but were at a normal level in 7 children, 5 of whom were < 5 y of age. Serum IgA antibodies to H. pylori were elevated in 40/105 children (38%). The levels of IgG and IgA antibody titers to H. pylori correlated with age (p < 0.001 and p < 0.02, respectively). IgG titers were reduced by > or = 50% in 85% (83/98; median follow-up 0.6 y) of children after therapy. In 56 such children eradication was verified by negative histology or urea breath test but I such child showed Helicobacters on histologic examination. Of the 15 children whose IgG titers dropped by < 50%, 7 were considered positive and 4 negative on the basis of histology or urea breath test. In 3 children, IgG titers returned to pretreatment levels 1 y after a 50% drop was seen. Serology is 1 alternative for monitoring H. pylori infection in children, although its sensitivity is lower in very young children. The length of follow-up needed after eradication, however, is unclear.

Real-time quantitative PCR for detection of Helicobacter pylori

Helicobacter pylori is one of the most common chronic infections in humans, in whom it is a key etiological factor in peptic ulcer disease, gastric mucosa-associated lymphoid tissue lymphoma, and gastric adenocarcinoma. Humans are the bacterium's only host. Here we report the development of a real-time quantitative (Q) PCR-based assay to measure ureC gene copy number to detect H. pylori, based on the fact that there is only one copy of the ureC gene per bacterium. Upon optimization of LightCycler Q-PCR conditions, we obtained a standard curve with a linear range (correlation coefficient = 1) across six logs of DNA concentration. We were able to accurately quantify as few as 1,000 bacteria in our assay. Analysis of variance on 15 randomly selected clinical samples showed good reproducibility of this assay. Comparison of Q-PCR results with bacterial culture and histopathological results from an additional 85 clinical biopsy samples showed a significant difference for the presence of H. pylori. Many samples that were negative for H. pylori by culture and histopathology were positive by Q-PCR. Contamination of PCR by H. pylori or H. pylori genetic material could not be ruled out. In summary, we developed a rapid, sensitive, and real-time Q-PCR method for detecting H. pylori. This technique offers a significant improvement over other available methods for detecting H. pylori in clinical and research samples.

In diffuse atrophic gastritis, routine histology underestimates Helicobacter pylori infection

BACKGROUND

histologic detection of shows high diagnostic accuracy in chronic nonatrophic gastritis. However, when atrophy occurs, the sensitivity of bacterial detection varies. This study assessed the routine histologic sensitivity for current infection in patients with atrophic gastritis, with and without intestinal metaplasia.

STUDY

five hundred and ten consecutive patients with diffuse chronic atrophic gastritis, with (174 cases) and without (336 cases) intestinal metaplasia, were investigated following the Sydney System recommendations. In cases with negative tissue staining for Helicobacter-like organisms, serum immunoglobulin G (IgG) antibodies to were assayed.

RESULTS

the overall rate of positive staining for Helicobacter-like organisms was 51.8% (264 of 510 cases), 62.8% and 30.4% in cases without and with intestinal metaplasia, respectively. Serum IgG antibody determination was consistent with current infection in 180 (73.2%) of the 246 cases with negative histology. detection rate was significantly lower ( < 0.01) in Grade 3 than in Grade 1 atrophy. When intestinal metaplasia was present, histologic bacterial detection progressively decreased, from 46.3% to 20%, depending on severity. infection was found by histology in 42.2% and in 56.2% of cases with inactive and active disease, respectively. Overall, the diagnostic accuracy of histology was significantly lower ( <0.001) than that of histology combined with serology.

CONCLUSIONS

most (87.1%) diffuse chronic atrophic gastritis patients showed serum antibody IgG levels consistent with current infection, although histology was positive in only 59.5% of cases. Gastritis activity and current infection did not ever correlate in the presence of mucosal atrophy and/or intestinal metaplasia. Routine biopsy sampling, hematoxylin and eosin staining, and Giemsa staining therefore underestimated the true prevalence of infection.

Reliability of Helicobacter pylori and CagA serological assays

Background serological assays for Helicobacter pylori are commonly used without knowledge of reliability. This information is needed to define the ability of serological tests to determine either new cases of infection or loss of infection in longitudinal studies. We evaluated the reproducibility and the interrelationships of serological test results for H. pylori and cytotoxin-associated gene product A (CagA) enzyme-linked immunoassays within a subset of participants in a population-based study. Stored samples from 1,229 participants in the third U.S. National Health and Nutrition Examination Survey were replicate serologically tested for H. pylori and CagA. Overall disagreement was 3.4% between duplicate tests for H. pylori (or 2.3% if equivocal results were disregarded). Six percent of samples positive on the first test had an immune serum ratio at least 30% lower on repeat testing. The odds ratio for H. pylori seropositivity on retesting was 2.8 (95% confidence interval [CI] = 1.8 to 4.5) when CagA serology was positive versus when it was negative. CagA antibody was found among 47.8% of H. pylori-equivocal and 7.0% of H. pylori-negative samples. CagA-positive yet H. pylori-negative samples were more likely to occur among Mexican Americans (odds ratio, 5.2; 95% CI = 2.4 to 11.4) and non-Hispanic blacks (odds ratio, 5.5; 95% CI = 2.3 to 13.0) than among non-Hispanic whites. Relying on repeated H. pylori serological tests over time to determine infection rates may result in misinterpretation due to limits in test reproducibility. CagA testing may have a role in verifying infection.