Comparison of commercial serological tests for detection of Helicobacter pylori antibodies

A combination of serum anti-Helicobacter pylori antibody titer and Kyoto classification score could provide a more accurate diagnosis of H pylori

BACKGROUND

We previously showed that the endoscopic Kyoto classification for gastritis could predict Helicobacter pylori infection in individuals with a high negative titer of serum anti-H pylori antibodies. This study evaluated H pylori infection and the Kyoto classification score in patients with a low negative titer (<3 U/ml), high negative titer (3-9.9 U/ml), low positive titer (10-49.9 U/ml), and high positive titer (≥50 U/ml).

METHODS

Serum antibody levels, Kyoto classification score and histology were investigated in 870 individuals with no history of H pylori-eradication therapy. Urea breath tests (UBTs) were additionally conducted for patients with a low negative titer and a Kyoto score ≥1 or an antibody titer ≥10 U/ml and a Kyoto score of 0 or 1. UBTs and/or histological studies were conducted for participants with a high negative titer.

RESULTS

False diagnoses based on anti-H pylori antibody titers were observed in 0.3% of the low-negative-titer group, 11.7% of the high-negative-titer group, 18.9% of the low-positive-titer group and 2.2% of the high-positive-titer group. Surprisingly, false diagnoses based on antibody titers were noted in 63.2% of patients with a low positive titer and a Kyoto score of 0 and in 62.5% of patients with a high negative titer and a Kyoto score ≥2, respectively.

CONCLUSIONS

Endoscopic findings could predict false diagnoses determined using serum antibody titers.

Non-invasive diagnostic tests for Helicobacter pylori infection

BACKGROUND

Helicobacter pylori (H pylori) infection has been implicated in a number of malignancies and non-malignant conditions including peptic ulcers, non-ulcer dyspepsia, recurrent peptic ulcer bleeding, unexplained iron deficiency anaemia, idiopathic thrombocytopaenia purpura, and colorectal adenomas. The confirmatory diagnosis of H pylori is by endoscopic biopsy, followed by histopathological examination using haemotoxylin and eosin (H & E) stain or special stains such as Giemsa stain and Warthin-Starry stain. Special stains are more accurate than H & E stain. There is significant uncertainty about the diagnostic accuracy of non-invasive tests for diagnosis of H pylori.

OBJECTIVES

To compare the diagnostic accuracy of urea breath test, serology, and stool antigen test, used alone or in combination, for diagnosis of H pylori infection in symptomatic and asymptomatic people, so that eradication therapy for H pylori can be started.

SEARCH METHODS

We searched MEDLINE, Embase, the Science Citation Index and the National Institute for Health Research Health Technology Assessment Database on 4 March 2016. We screened references in the included studies to identify additional studies. We also conducted citation searches of relevant studies, most recently on 4 December 2016. We did not restrict studies by language or publication status, or whether data were collected prospectively or retrospectively.

SELECTION CRITERIA

We included diagnostic accuracy studies that evaluated at least one of the index tests (urea breath test using isotopes such as 13C or 14C, serology and stool antigen test) against the reference standard (histopathological examination using H & E stain, special stains or immunohistochemical stain) in people suspected of having H pylori infection.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened the references to identify relevant studies and independently extracted data. We assessed the methodological quality of studies using the QUADAS-2 tool. We performed meta-analysis by using the hierarchical summary receiver operating characteristic (HSROC) model to estimate and compare SROC curves. Where appropriate, we used bivariate or univariate logistic regression models to estimate summary sensitivities and specificities.

MAIN RESULTS

We included 101 studies involving 11,003 participants, of which 5839 participants (53.1%) had H pylori infection. The prevalence of H pylori infection in the studies ranged from 15.2% to 94.7%, with a median prevalence of 53.7% (interquartile range 42.0% to 66.5%). Most of the studies (57%) included participants with dyspepsia and 53 studies excluded participants who recently had proton pump inhibitors or antibiotics.There was at least an unclear risk of bias or unclear applicability concern for each study.Of the 101 studies, 15 compared the accuracy of two index tests and two studies compared the accuracy of three index tests. Thirty-four studies (4242 participants) evaluated serology; 29 studies (2988 participants) evaluated stool antigen test; 34 studies (3139 participants) evaluated urea breath test-13C; 21 studies (1810 participants) evaluated urea breath test-14C; and two studies (127 participants) evaluated urea breath test but did not report the isotope used. The thresholds used to define test positivity and the staining techniques used for histopathological examination (reference standard) varied between studies. Due to sparse data for each threshold reported, it was not possible to identify the best threshold for each test.Using data from 99 studies in an indirect test comparison, there was statistical evidence of a difference in diagnostic accuracy between urea breath test-13C, urea breath test-14C, serology and stool antigen test (P = 0.024). The diagnostic odds ratios for urea breath test-13C, urea breath test-14C, serology, and stool antigen test were 153 (95% confidence interval (CI) 73.7 to 316), 105 (95% CI 74.0 to 150), 47.4 (95% CI 25.5 to 88.1) and 45.1 (95% CI 24.2 to 84.1). The sensitivity (95% CI) estimated at a fixed specificity of 0.90 (median from studies across the four tests), was 0.94 (95% CI 0.89 to 0.97) for urea breath test-13C, 0.92 (95% CI 0.89 to 0.94) for urea breath test-14C, 0.84 (95% CI 0.74 to 0.91) for serology, and 0.83 (95% CI 0.73 to 0.90) for stool antigen test. This implies that on average, given a specificity of 0.90 and prevalence of 53.7% (median specificity and prevalence in the studies), out of 1000 people tested for H pylori infection, there will be 46 false positives (people without H pylori infection who will be diagnosed as having H pylori infection). In this hypothetical cohort, urea breath test-13C, urea breath test-14C, serology, and stool antigen test will give 30 (95% CI 15 to 58), 42 (95% CI 30 to 58), 86 (95% CI 50 to 140), and 89 (95% CI 52 to 146) false negatives respectively (people with H pylori infection for whom the diagnosis of H pylori will be missed).Direct comparisons were based on few head-to-head studies. The ratios of diagnostic odds ratios (DORs) were 0.68 (95% CI 0.12 to 3.70; P = 0.56) for urea breath test-13C versus serology (seven studies), and 0.88 (95% CI 0.14 to 5.56; P = 0.84) for urea breath test-13C versus stool antigen test (seven studies). The 95% CIs of these estimates overlap with those of the ratios of DORs from the indirect comparison. Data were limited or unavailable for meta-analysis of other direct comparisons.

AUTHORS' CONCLUSIONS

In people without a history of gastrectomy and those who have not recently had antibiotics or proton ,pump inhibitors, urea breath tests had high diagnostic accuracy while serology and stool antigen tests were less accurate for diagnosis of Helicobacter pylori infection.This is based on an indirect test comparison (with potential for bias due to confounding), as evidence from direct comparisons was limited or unavailable. The thresholds used for these tests were highly variable and we were unable to identify specific thresholds that might be useful in clinical practice.We need further comparative studies of high methodological quality to obtain more reliable evidence of relative accuracy between the tests. Such studies should be conducted prospectively in a representative spectrum of participants and clearly reported to ensure low risk of bias. Most importantly, studies should prespecify and clearly report thresholds used, and should avoid inappropriate exclusions.

Comparison of salivary and serum enzyme immunoassays for the diagnosis of Helicobacter pylori infection

Infection with Helicobacter pylori has been established as an important risk factor for the development of peptic ulcer disease, gastritis and gastric cancer. The diagnosis of H pylori infection can be established by invasive or noninvasive techniques. Two noninvasive enzyme immunoassays (EIAs) for antibody detection - HeliSal and Pylori Stat - were compared with histology. Both assays detect immunoglobulin (Ig) G directed against purified H pylori antigen. The test populations consisted of 104 consecutive patients scheduled for upper gastrointestinal endoscopy. Of these patients, 97 (93%) had symptoms compatible with peptic ulcer disease. Saliva and serum were collected simultaneously at the time of endoscopy. Salivary EIA had a sensitivity of 66%, specificity of 67%, positive predictive value of 67% and negative predictive value of 66% compared with the serum EIA, where the results were 98%, 48%, 64% and 96%, respectively. Although the salivary EIA is an appealing noninvasive test, it was not a sensitive and specific assay. The serum EIA also lacked specificity, but was highly sensitive with a good negative predictive value. Although a negative serum EIA rules out H pylori infection, a positive result must be interpreted in the clinical context and confirmed with a more specific measure.

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.

Detection and evaluation of salivary antibodies to Helicobacter pylori in dyspeptic patients

Helicobacter pylori infection is one of the most prevalent infections in humans. The high prevalence and the association with peptic ulceration and gastric cancer require simple and non-invasive methods for the diagnosis of the infection. Detection of salivary anti-H. pylori IgG antibodies has advantages compared with those on serum. In this study, salivary immunoglobulin G response to H. pylori was evaluated in 100 consecutive dyspeptic patients by enzyme-linked immunosorbent assay (ELISA), in comparison with culture and histopathologic examination of gastric biopsy specimens obtained at endoscopic procedures and assessed the accuracy of salivary diagnosis of the infection. The overall sensitivity and specificity of the test were 87 and 73%, respectively. These results suggest that saliva testing for H. pylori antibodies could be used reliably for screening dyspeptic patients in general practice, especially in children in whom venesection is more difficult.

Acute coronary syndrome and chronic infection in the Cork coronary care case-control study

OBJECTIVE

To examine the association between chronic infection and cumulative burden of infection and acute coronary syndrome.

DESIGN

The 5C (Cork coronary care case-control) study was a community based case-control study. Patients and controls underwent a standard physical examination and had blood samples taken for serological analysis for Helicobacter pylori (IgG), Chlamydia pneumoniae (IgA, IgM, and IgG), cytomegalovirus (IgG), and herpes simplex virus types 1 and 2 (IgG).

SETTING

Patients were recruited from four hospitals in Cork City and Mallow Town. Controls, individually matched on age and sex, were selected by incident density sampling from the same general practices as the referent case.

MAIN OUTCOME MEASURES

Age and sex adjusted and fully adjusted odds ratios for acute coronary syndrome by seropositivity and by increasing number of infections.

RESULTS

Cases and controls did not differ significantly in seropositivity to C pneumoniae, cytomegalovirus, herpes simplex viruses, and H pylori. In unconditional logistic regression analysis adjusted for age, sex, waist to hip ratio, smoking, physical activity, alcohol consumption, and social class there was no evidence of an increasing risk for acute coronary syndrome with increasing burden of infection.

CONCLUSIONS

The findings do not support an association between specific infectious agents and acute coronary syndrome and do not provide evidence of a burden of infection effect.

Serologic prevalence of antibodies to Helicobacter pylori in internationally adopted children

BACKGROUND

Helicobacter pylori (H. pylori) infection has been linked to gastritis, diarrhea, peptic ulcers, failure-to-thrive, anemia, as well as predisposition to gastric malignancies. Because many internationally adopted children have diarrhea, failure-to-thrive, and anemia on arrival to the US, we determined the prevalence of HP antibodies among these children.

METHODS

Serum samples from 226 unselected children from 18 countries who were evaluated in the International Adoption Clinic at New England Medical Center were tested for antibodies to H. pylori. The results of serologic screening were analyzed in relation to age at adoption, site of residence prior to adoption, weight and height, and the presence or absence of anemia, diarrhea, or intestinal parasites.

RESULTS

31% of internationally adopted children had antibodies to H. pylori. The presence of H. pylori-antibodies was associated with residence in an orphanage (vs. foster care) prior to adoption, older age at adoption, and coinfection with intestinal parasites. No direct effects on height or weight were identified; no associations with diarrhea or anemia were found.

CONCLUSIONS

Internationally adopted children have a high incidence of exposure to H. pylori, as diagnosed serologically. Residence in an orphanage (compared with foster care), older age at adoption, and coinfection with intestinal parasites were more common among children seropositive for anti-H. pylori antibodies.

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.

Food/nutrient intake and risk of atrophic gastritis among the Helicobacter pylori-infected population of northeastern Japan

Although Helicobacter pylori (H. pylori ) infection is considered a key risk factor for atrophic gastritis, along with other environmental factors, it is still unclear which factor is involved in the development of atrophic gastritis among H. pylori-infected subjects. In the present cross-sectional study, therefore, we analyzed various dietary factors in relation to the presence of atrophic gastritis among H. pylori-infected subjects who participated in a health check-up program in a town in northeastern Japan. One thousand and seventy-one subjects (362 males and 709 females) who provided both self-administered validated food frequency questionnaires and blood samples were the basis for the study, and all of them were serologically positive for H. pylori immunoglobulin G (IgG) antibody. Among them, 663 (223 males and 440 females) were diagnosed as having atrophic gastritis on the basis of serum pepsinogen levels. Odds ratios (OR) and 95% confidence intervals (95% CI) were calculated based on tertile categories of subjects without atrophic gastritis, using logistic regression analysis. Among females, high consumptions of rice (OR = 1.6, 95% CI: 1.1-2.3), cod roe (OR = 1.5, 95% CI: 1.0-2.2) and cuttlefish (OR = 1.5, 95% CI: 1.0-2.3) were associated with a moderately increased risk of atrophic gastritis after adjustment for age (P for trend = 0.02 for these items). Among males, high consumptions of rice and miso soup showed a tendency toward an increased risk (P for trend = 0.12 and 0.13, respectively). Vegetables and fruits showed no association among either males or females. From these results, it is suggested that the dietary habits of consumers of traditional Japanese foods may play a role in the development of atrophic gastritis after H. pylori infection.

Ethnic difference in serology of Helicobacter pylori CagA between Japanese and non-Japanese Brazilians for non-cardia gastric cancer

The usefulness of serology against CagA of Helicobacter pylori as a biomarker to identify high-risk individuals for non-cardia gastric cancer (ncGC) remains unclear among several ethnic populations with a high prevalence of cagA-positive strains. We investigated ethnic differences of CagA serology in two sets of case-control subjects, Japanese-Brazilians (JB) and non-Japanese Brazilians (NJB). We performed a cross-sectional comparison of IgG antibody titers to CagA (CagA-Ab) and the combination of CagA-Ab with conventional surface antigen (Hp-Ab) in 80 JB and 178 NJB ncGC patients and their controls (160 JB and 178 NJB). The level of CagA-Ab titer in cancer cases was significantly higher in NJB than in JB. The strength of the association between CagA-Ab seropositivity (+) (> or = 10 U/ml) and ncGC was almost 2-fold higher in NJB than in JB [odds ratio (OR) (95% confidence interval), 4.5 (2.6-7.8) and 2.1 (1.2-3.6), respectively]. However, in both JB and NJB, the OR was highest in CagA-Ab(+) subjects with low titer (10-29 U/ml), and decreased inversely with elevating CagA-Ab titer. In addition, the serological status of CagA-Ab(+) and Hp-Ab(-) showed a similar close association with ncGC between JB and NJB [5.4 (1.9-15.3) and 5.4 (2.0-15.0), respectively]. These results suggest that although the roles of CagA in the carcinogenic process of ncGC might be different between JB and NJB, the CagA-Ab could be a useful marker for ncGC, independently of ethnicity, particularly in high-risk individuals with the serological status of CagA-Ab(+) with low IgG titer or combined with Hp-Ab(-).

Changing rates of Helicobacter pylori testing and treatment in patients with peptic ulcer disease

OBJECTIVES

The aim of this study was to identify temporal trends in the rate of Helicobacter pylori (H. pylori) testing, prevalence, and treatment among patients with peptic ulcer disease in Olmsted County, MN, from 1984 through 1997.

METHODS

All 3317 Olmsted County residents with a clinical diagnosis of peptic ulcer disease at the Mayo Clinic from 1984 through 1997 were identified. The complete medical records of an age-, sex-, and calendar year-stratified random sample were reviewed (n = 720); 298 patients (41%) had confirmed peptic ulcer disease. Changes in proportions of H. pylori testing, infection, and treatment over time were analyzed by logistic regression.

RESULTS

Of the 298 patients with confirmed peptic ulcer disease, 32% were tested for H. pylori; 36% were positive for infection, of whom 66% received antibiotic therapy. The rate of testing for H. pylori increased from 0% in 1984 to 96% in 1997, but the prevalence of infection did not change (36.4% vs 36.5%). The rate of treatment of those infected increased from 0% to 95%. By logistic regression, calendar year was associated with H. pylori testing and treatment but not infection. Recent use of nonsteroidal anti-inflammatory drugs was reported by 58% of patients, and 44% presented with GI bleeding.

CONCLUSIONS

Physicians' practice of testing and treating for H. pylori in patients with confirmed peptic ulcer disease has steadily increased over the past 14 yr. However, in our study, only 36% of these patients were infected with H. pylori, whereas the majority used nonsteroidal anti-inflammatory drugs (NSAIDs). Therefore, testing seems to be more appropriate than empiric treatment in patients with peptic ulcer disease.

The role of Helicobacter pylori infection in the cause of squamous cell carcinoma of the larynx

OBJECTIVE

Helicobacter pylori can cause chronic infection that has been linked to the development of both benign and malignant disease of the aerodigestive tract. The purpose of this study was to determine the link between H pylori infection and squamous cell carcinoma of the larynx (SCCL).

METHODS

We estimated the presence of IgG antibodies against H pylori antigens by using ELISA technique in the sera of 26 patients with SCCL and 32 matched controls without carcinoma of the larynx.

RESULTS

The incidence of seropositivity of patients with SCCL was 73.07% and of controls was 40.62%. These data support an etiologic role for H pylori infection on development of SCCL (chi(2) = 4.85, P< 0.05).

CONCLUSION

H pylori infection of the upper aerodigestive tract might result in mucosal disruption, allowing for subsequent transformation by known carcinogens such as tobacco and alcohol.

Serological Immunoglobulin G antibody titers to Helicobacter pylori in Japanese Brazilian and Non-Japanese Brazilian gastric cancer patients and controls in São Paulo

Helicobacter pylori (H. pylori) infection is considered a cause of gastric cancer (GC), though evidence for this association is scarce in high-risk areas. Possible case control and/or ethnic differences were investigated as to the presence of H. pylori and its immunogloblin G antibody titer in the multi-ethnic city of São Paulo, where the incidence of GC is relatively high. We performed a cross-sectional comparison of antibody titers to H. pylori in Japanese Brazilian, and non-Japanese Brazilian GC patients and their controls. Japanese Brazilian patients were matched by age, sex and ethnicity with two controls, while non-Japanese Brazilian patients were matched as above with one control. Among Japanese Brazilians, 59 of 93 (63.4%) patients with GC and 127 of 186 (68.3%) controls were positive for H. pylori-specific antibody (odds ratio (OR) = 0.80, 95% confidence interval (CI) = 0.47 - 1.36), while among non-Japanese Brazilians, 171 of 228 patients with GC (75.7%) and 178 of 226 controls (78.8%) were positive (OR = 0.84, 95% CI = 0.54 - 1.30). The median serum antibody titer was lower in cases than in controls in both ethnic groups. A high titer (H. pylori titer > or = 50) was associated with less likelihood of GC for both ethnic groups (for Japanese Brazilians, OR = 0.39, 95% CI = 0.16 - 0.92; for non-Japanese Brazilians, OR = 0.56, 95% CI = 0.31 - 1.02). The high titer can be regarded as a sign of the necessity of eradication, and low titer is regarded as a sign of the necessity of close screening for GC in both ethnic groups, because extended atrophy may cause spontaneous disappearance of H. pylori from the stomach.

Helicobacter pylori is not a risk factor for hepatic encephalopathy

BACKGROUND

Helicobacter pylori infection has been described as a risk factor for hepatic encephalopathy in patients with chronic liver disease although the topic remains controversial.

AIMS

To determine whether Helicobacter pylori infection is an independent predictive factor for encephalopathy in patients with liver cirrhosis.

METHODS

Clinical, epidemiological, analytical and nutritional parameters of 205 patients were collected. Helicobacter pylori infection was determined by serology. Encephalopathy (grade II or higher) was clinically assessed during follow-up. The relationship between each parameter and encephalopathy was analysed by Kaplan-Meier curves and the Log rank test. The most significant parameters underwent multivariate analysis by Cox regression.

RESULTS

Twenty-five variables were related to encephalopathy in the bivariate analysis. Multivariate analysis selected five independent factors: previous bouts of encephalopathy (Odds ratio 3.79; 95% confidence interval 1.94-7.38), albumin (Odds ratio 0.86; 95% confidence interval 0.80-0.92), tricipital skin fold (Odds ratio 0.79; 95% confidence interval 0.66-0.95) chronic pulmonary disease (Odds ratio 2.78, 95% confidence interval; 1.31-5.92), and on-going alcoholism (Odds ratio 2.62; 95% confidence interval 1.16-5. BB).

CONCLUSIONS

Helicobacter pylori is not an independent risk factor for hepatic encephalopathy.

Evaluation of five commercial serological tests for the detection of Helicobacter pylori infection in Chinese

BACKGROUND

Commercial serological tests for the detection of Helicobacter pylori infection must be locally validated. We evaluated the accuracy of five commercial tests in the Chinese population.

METHODS

Serum samples were collected from patients referred for upper endoscopy. Antral biopsies were taken for histological examination and culture of H. pylori. The gold standard for diagnosing H. pylori infection was positive histological staining and/or positive H. pylori culture. The serum samples were tested for H. pylori antibodies using the following tests: (i) Cobas Core Anti-H. pylori EIA; (ii) GAP IgG; (iii) GAP IgM; (iv) H. pylori microwell EIA (Quidel); and (v) Premier H. pylori. The sensitivity, specificity and accuracy of each test was calculated according to the manufacturers' instructions or according to a new cut-off value.

RESULTS

A total of 158 patients were recruited amongst whom 114 (72%) were H. pylori-positive. Indeterminate results varied from 7% to 19%. The accuracy of the tests varied from 57% to 85%. By using new cut-off values, the accuracy was much improved, ranging from 73.4% to 86.7%.

CONCLUSIONS

By defining new cut-off values for the Chinese population, we were able to improve the performance of some of the serology tests. This illustrates the importance of local validation.

Helicobacter pylori and dyspepsia: a population-based study of the organism and host

OBJECTIVE

The role of Helicobacter pylori (HP) infection in dyspepsia in the absence of peptic ulcer remains controversial. Specific attributes of the organism or the host response may be important. We aimed to determine whether HP infection overall, CagA status, serum gastrin, or serum pepsinogen levels are associated with dyspepsia in the community.

METHODS

A self-report bowel disease questionnaire was mailed to a random sample of Olmsted County, Minnesota residents, aged 20-50 yr. All respondents who reported symptoms of dyspepsia or irritable bowel syndrome (cases) and all respondents without significant GI symptoms (controls) were invited to participate (n = 260). They were each assessed by a physician and their medical records reviewed. Serum was obtained to measure HP and CagA antibodies, pepsinogen I and II levels, and basal serum gastrin using validated assays.

RESULTS

Of the 148 (57%) subjects who agreed to participate, 36 had dyspepsia (17 had ulcer-like dyspepsia), 35 had irritable bowel syndrome (IBS) without dyspepsia, and 77 were asymptomatic. The proportion who were seropositive for HP were 17% in dyspepsia (24% in ulcer-like dyspepsia), 20% in IBS, and 12% in asymptomatic controls. HP was not associated with dyspepsia, ulcer-like dyspepsia, or IBS after adjusting for age. Pepsinogen levels and serum gastrin were not associated with any of the conditions studied. However, CagA antibody positivity was associated with IBS (p < 0.05), and a borderline statistically significant association with dyspepsia was detected (p = 0.08).

CONCLUSIONS

In this community, HP infection overall does not seem to explain dyspepsia, although the role of CagA-positive HP strains deserve further study.

Validation of serological tests forHelicobacter pylori infection in an Irish population

BACKGROUND

Serological tests for Helicobacter pylori using laboratory and 'office' formats are commonly used, easy to perform, inexpensive and widely available. Local validation of test performance is required.

AIMS

This study examined the performance of a laboratory and 'office' ELISA in a population of Irish dyspeptics presenting for endoscopy.

METHODS

Consecutive patients presenting for endoscopy had blood drawn at sedation. Samples were analysed using two ELISA formats; a standard laboratory format and an 'office' ELISA test card. H. pylori infection was diagnosed by analysis of antral and corpus biopsies using the rapid urease test, culture and histology. A combination of two positive invasive tests was considered indicative of infection.

RESULTS

The sensitivity and specificity of laboratory ELISA was 82.4% and 85% respectively while the values for the 'office' ELISA were 87.7% and 85.7% respectively. In patients under 45 years sensitivities and specificities of the 'office' test exceeded 90%. The two serological tests agreed in 87.5% of subjects.

CONCLUSIONS

Both tests performed satisfactorily. However, indeterminate results impaired the usefulness of the laboratory ELISA particularly when using a new cut-off. The 'office' ELISA performed particularly well in young patients. A simpler test using antigens from locally prevalent strains to optimise accuracy is awaited.

Is upper gastrointestinal radiography a cost-effective alternative to a Helicobacter pylori "test and treat" strategy for patients with suspected peptic ulcer disease?

OBJECTIVE

Current clinical consensus supports an initial Helicobacter pylori (HP) "test and treat" approach when compared to immediate endoscopy for patients with suspected peptic ulcer disease. Alternative diagnostic approaches that incorporate upper GI radiography (UGI) have not been previously evaluated. We sought to determine the cost effectiveness of UGI compared to a HP test and treat strategy, incorporating recent data addressing the reduced prevalence of HP, lower cost of diagnostic interventions, and reduced attribution of PUD to HP.

METHODS

Using decision analysis, three diagnostic and treatment strategies were evaluated: 1) Test and Treat--initial HP serology, treat patients who test positive with HP eradication and antiulcer therapy; 2) Initial UGI series--treat all patients with documented ulcer disease with HP eradication and antiulcer therapy; and 3) Initial UGI series, HP serology if ulcer present--treat ulcer and HP based on diagnostic test results.

RESULTS

The estimated cost per ulcer cured for each strategy were as follows: test and treat, $3,025; initial UGI, $3,690; and UGI with serology, $3,790. The estimated cost per patient treatment were: test and treat, $498; initial UGI, $610; and UGI with serology, $620. When UGI reimbursement was decreased to less than $50, the UGI strategies yielded a lower cost per patient treated than the test and treat strategy.

CONCLUSION

At the current level of reimbursement, UGI should not be considered a cost-effective alternative to the HP test and treat strategy for the initial evaluation of patients with suspected peptic ulcer disease.

Treatment of Helicobacter pylori infection in clinical practice in the United States: results from 224 patients

Our objectives were to define treatment success, compliance, and side effects for treatment of Helicobacter pylori in clinical practice. In all, 224 consecutive patients received Helicobacter pylori treatment: 97 received two weeks of bismuth subsalicylate, metronidazole, tetracycline four times a day with a H2-receptor antagonist twice a day (BMT); 89 received one week of metronidazole, lansoprazole, and clarithromycin twice a day (MLC); and 38 received one week of BMT with lansoprazole twice a day (BMT-PPI). Cure rates were: BMT 81% (95% CI 74-89%), MLC 90% (95% CI 84-96%) BMT-PPI 87% (95% CI 81-92%). More patients prescribed a bismuth-based regimen discontinued medications due to side effects compared to MLC (P = 0.049). Nausea was more common for BMT compared to MLC (P = 0.04). In conclusion, treatment of Helicobacter pylori infection with a one-week course of MLC achieves a high rate of cure in clinical practice. Significantly fewer patients prescribed PPI-based therapy discontinue medications due to side effects as compared to bismuth-based triple therapy.

Alpha1-antitrypsin deficiency may be a risk factor for duodenal ulcer in patients with Helicobacter pylori infection

BACKGROUND

Most individuals with Helicobacter pylori infection in Western countries have no evidence of peptic ulcer disease (PUD). We therefore assessed the PiZ deficiency variant of the major plasma protease inhibitor alpha1-antitrypsin (alpha1AT) as a risk factor for PUD in H. pylori-infected individuals.

METHODS

The cohort comprised 100 patients with endoscopically or surgically proven PUD (30 patients with duodenal ulcer (DU) and 70 patients with gastric ulcer (GU)) and 162 age- and sex-matched controls with PUD-negative endoscopic findings and no history of PUD. Plasma samples were screened for alpha1AT deficiency (PiZ) with an enzyme-linked immunosorbent assay (ELISA) and phenotyped by isoelectric focusing. H. pylori infection was evaluated with an IgG ELISA technique.

RESULTS

Among the 262 patients 17 (6.5%) were positive for the PiZ alpha1AT deficiency, a frequency of the same magnitude as in the Swedish general population (4.7%). Of the PiZ carriers 76% (13 of 17) had H. pylori antibodies compared with 61% (151 of 245) of the non-PiZ carriers (NS). The prevalence of DU tended to be higher in H. pylori-positive PiZ carriers than in non-PiZ carriers (15.4%, 4 of 26 versus 0 of 4). Furthermore, among patients with DU a high PiZ allele frequency (13.3%, 4 of 30) was found compared with the general population (4.7%) (odds ratio (OR), 3.2; 95% confidence interval (CI), 1.09-8.94; P = 0.02). All DU patients carrying the PiZ allele were positive for H. pylori. In addition, four of five PiZ carriers with H. pylori infection and PUD had DU.

CONCLUSIONS

The PiZ allele may be a contributing factor in the development of DU in H. pylori-positive individuals.

How useful is the detection kit for antibody to Helicobacter pylori in urine (URINELISA) in clinical practice?

OBJECTIVE

Increased knowledge of the significance of Helicobacter pylori (H. pylori) infection in gastric disorders has accelerated the trend of screening patients with dyspepsia for its infection. Serological examination of antibody for H. pylori has been widely performed. Recently, a urine-based enzyme-linked immunosorbent assay (URINELISA) kit for detection of antibody for H. pylori has been developed. Accordingly, we evaluated its diagnostic accuracy in clinical practice.

METHODS

Subjects of this study were 132 patients who presented at our university hospital because of dyspeptic symptoms (81 men, 51 women; age, 41.5+/-1.4 yr). 13C urea breath test, blood drawing for serological antibody for H. pylori infection by four different kits, and urine collection for the URINELISA test for detection of the antibody were performed. Diagnostic accuracy of the commercially available antibodies in serum and in urine were investigated using the results of the 13C urea breath test as the gold standard.

RESULTS

Sensitivity, specificity, and accuracy of URINELISA were 86.3% (95% confidence intervals [CI], 76-93%), 91.5% (95% CI, 81-97%), and 88.6% (95% CI, 82-93%), respectively, which were comparable to those of imported serological kits.

CONCLUSIONS

The URINELISA kit for detecting anti-H. pylori antibody in urine provides diagnostic accuracy comparable to that of imported kits for detecting antibodies in serum and is considered to be clinically useful for the diagnosis of H. pylori infection.

Use of a dried plasma collection card for simplified diagnosis of Helicobacter pylori infection

OBJECTIVES

To compare testing for Helicobacter pylori IgG antibodies using a dried plasma collection card device with specimens obtained by venepuncture.

METHODS

Eighty-four patients underwent testing for H. pylori IgG antibodies by venepuncture and by fingerstick using a single drop of blood placed on each of two dried plasma collection card devices. The correlation of venepuncture results to dried plasma card results was assessed.

RESULTS

There was a high degree of correlation of EIA results between venepuncture and dried plasma card specimens (r=0.98). The qualitative result of the first dried plasma card and venepuncture specimen testing differed in 7 of 84 patients and for the second dried plasma card differed in 7 of 82 patients. The first dried plasma card was 93% sensitive and 100% specific and the second was 93% sensitive and 98% specific as compared to the venepuncture result. There was a high degree of correlation between the first and second dried plasma cards (r=0.996).

CONCLUSIONS

The dried plasma collection card has adequate sensitivity and excellent specificity as compared to venepuncture specimens and is a feasible alternative for H. pylori IgG antibody testing.

Exploring novel vaccines against Helicobacter pylori: protective and therapeutic immunization

Infection of human stomach by Helicobacter pylori, a gram negative spiral bacterium first isolated in 1983 from a patient with chronic active gastritis (1), causes nearly all duodenal ulcers and most gastric ulcers and is associated with an increased risk of gastric adenocarcinoma (2). Current therapies for gastric infections include combination triple or quadruple therapy of antimicrobial and/or antiulcer agents for eradication of H. pylori infection (3). Development of the resistant strains and ecological niche (habitant) of the bacteria may cause relapse after the termination of the therapy. However, if effective, the high cost, difficulty of patient compliance and risk of selection for resistant strains make these therapeutic regimens impractical on a large scale, though effective on the laboratory trial stages. Studies of the pathogenesis of H. pylori have led to the identification of bacterial antigens and adherin proteins as candidates for inclusion as novel vaccines against these diseases (4-7). Both prophylactic and therapeutic vaccination have been demonstrated in animal models of H. pylori infection (8-10).

New immunological assays for the diagnosis of Helicobacter pylori infection

There are several types of immunological tests available for the diagnosis and management of Helicobacter pylori infection. Most commercially available serological kits use the enzyme linked immunosorbent assay (ELISA) test format. Originally the kits used crude antigen preparations although many of the newer kits use a more purified antigen preparation, with often increased specificity but lower sensitivity. Near patient test kits are based either on latex agglutination or immunochromatography. Generally they have low sensitivities compared with laboratory tests. Western blotting, ELISA, and recombinant immunoblot assays (RIBA) have also been developed into commercially available kits and can be used to indicate the presence of specific virulence markers. An antigen detection kit has been developed for the detection of Helicobacter pylori in faeces. Immunological reagents have also been combined with other diagnostic modalities to develop immunohistochemical stains and DNA immunoassays. Helicobacter pylori is now recognised as the cause of gastritis and most cases of peptic ulcer disease (PUD); its long term carriage increases the risk of gastric adenocarcinoma sixfold and it is designated as a class I carcinogen. H pylori has also been implicated as a cause of gastric mucosa associated lymphoid tissue lymphomas. Its relation to non-ulcer dyspepsia remains controversial. Additionally, long term carriage of the organism may be associated with short stature in young girls and, in the general population, as a possible risk factor for the development of vasospastic disorders and possibly skin immunopathology such as urticaria. With the recognition of H pylori as an important human pathogen, it has become one of the growing number of organisms to have its complete genome sequence mapped. Serology is an important method of determining colonisation status and can be used for diagnosis, as a screening procedure, or to follow the efficacy of eradication regimens. Most serological assays are in the ELISA format although some are based on the latex agglutination reaction. These latter are used principally as near patient assays. Most assays detect IgG in serum although some detect serum IgA. More recently developed assays detect IgA in saliva and the production of affinity purified antibodies has led to the development of an antigen detection assay for faecal specimens. Serological reagents have also been used in immunocytochemistry and to speed up the detection of amplified products of the polymerase chain reaction (PCR)-DNA immunoassays.

Eradication of Helicobacter pylori increases gastric acidity in patients with atrophic gastritis of the corpus-evaluation of 24-h pH monitoring

BACKGROUND

Recent studies have shown that the eradication of Helicobacter pylori results in a gastric acid secretion which decreases to normal levels in patients with duodenal ulcer disease. The aim of this study was to evaluate the effect of eradication of H. pylori in a 24-h study of gastric acidity in patients with atrophic gastritis of the corpus.

METHODS

Intragastric acidity was measured by continuous 24-h pH monitoring, and the histology of the gastric antrum and corpus were evaluated in 14 H. pylori-positive patients with histologically proven atrophic gastritis of the corpus (10 men, 4 women; mean age, 57 years) before and 1 year after anti-H. pylori therapy.

RESULTS

H. pylori was absent in 13 of 14 patients 1 year after treatment. Both gastritis and atrophy scores were significantly lower after eradication therapy (P < 0.01). The 24-h median pH and the percentage of 24-h pH readings above 4.0 units were significantly decreased after eradication therapy (from 5.12 +/- 0.36 to 2.69 +/- 0.21, and from 65.5 +/- 6.6% to 28.2 +/- 6.1%, P < 0.01, respectively.)

CONCLUSION

Eradication of H. pylori increases 24-h gastric acidity in patients with atrophic gastritis of the corpus. Improvement of the histology of the gastric antrum and corpus may lead to the normalization of gastric acidity.

An epizootic of lymphoplasmacytic gastritis attributed to Helicobacter pylori infection in cynomolgus monkeys (Macaca fascicularis)

An epizootic of subclinical lymphoplasmacytic gastritis occurred in cynomolgus monkeys maintained at our research facility. Gastric pathology data and histologic sections of 63 adolescent monkeys (2.5-3.5 years old) sacrificed during the epizootic were reviewed. Localized to multifocal reddening of the gastric mucosa was noted grossly in 7 of 44 (16%) monkeys harboring Helicobacter pylori, but not in any of 19 monkeys in which these bacteria were not seen. Gastritis, characterized by accentuation of lymphoplasmacytic infiltrates in antral and to a lesser degree cardiac mucosa, occurred in 42 of 63 (67%) monkeys evaluated and in 42 of 44 (93%) monkeys in which H. pylori was observed microscopically. Two monkeys with H. pylori infection had infiltrate scores that overlapped with the upper limit of scores of H. pylori-negative animals. Coincident with accentuated infiltrates were gastric gland epithelial hyperplasia, reduction in mucin content of surface and gland epithelia, and comparatively minor infiltrates of neutrophils in superficial lamina propria and gastric glands. Antral mucosa thickness often exceeded 1.5 to 2 times normal. Antral mucosal erosions occurred in 7 of 44 (16%) monkeys with H. pylori. Argyrophilic bacteria morphologically consistent with H. pylori were present in antral and less commonly cardiac mucosal glands. Intensity of bacterial colonization correlated with lymphoplasmacytic infiltrates (r = 0.754) and hyperplasia (r = 0.700), although responses were quite variable. These bacteria were not detected in fundic mucosa except in instances where parietal cells were substantially depleted in glands coincident with localized increases in lamina propria inflammatory cell infiltrates. Helicobacter heilmannii-like organisms (HHLOs) were present in fundic glands of all 63 monkeys; colonization was often pronounced. Scores for fundic mucosal inflammation did not correlate with presence or intensity of colonization with HHLOs (r = 0.005). Rather, fundic inflammation scores positively correlated with the antral inflammation scores (r = 0.548). Bacteria morphologically, biochemically, and genetically consistent with H. pylori were cultured from gastric mucosal specimens confirming bacterial identification. These findings demonstrate that adolescent cynomolgus monkeys are susceptible to natural infection with H. pylori and develop many morphologic hallmarks of H. pylori-related gastritis in humans.

Epidemiology of peptic ulcer disease in cirrhotic patients: role of Helicobacter pylori infection

OBJECTIVE

The aim of this study was to investigate the clinical and epidemiological factors associated with the appearance of peptic ulcer in patients with cirrhosis and, in particular, the role of Helicobacter pylori infection.

METHODS

A total of 201 of 220 consecutive patients included in a prospective study that aimed to evaluate the effect of dietary intervention on cirrhotic complications and survival underwent upper gastrointestinal endoscopy. At entry, an epidemiological and clinical questionnaire was completed and the presence of peptic ulcer disease or esophageal varices at endoscopy was prospectively collected. Sera were obtained and stored at -70 degrees C until analyzed, being tested afterward for Helicobacter pylori antibodies using a commercial ELISA kit.

RESULTS

Eleven of 201 patients had borderline anti-Helicobacter pylori IgG titers and were excluded from further analysis. In the remaining 190 patients, point prevalence of peptic ulcer was 10.5% and lifetime prevalence 24.7%. Multivariate analysis selected male sex (OR 2.3; 95%CI 1.09-4.89) and Helicobacter pylori seropositivity (OR: 1.7, 95%CI 1.02-2.81) as the variables independently related to peptic ulcer disease.

CONCLUSIONS

Male sex and seropositivity for Helicobacter pylori are the major risk factors for peptic ulcer in cirrhosis.

Helicobacter pylori infection and gastric neoplasia: correlations with histological gastritis and tumor histology

OBJECTIVE

Several authors have reported an association between Helicobacter pylori (H. pylori) and gastric carcinoma, but the data are conflicting. Atrophic gastritis and intestinal metaplasia (IM) have also been linked to gastric carcinoma, especially the intestinal tumor type. We investigated the relationship between H. pylori infection, gastric neoplasms, and histological gastritis.

METHODS

A total of 105 patients with gastric carcinoma, 36 patients with gastric adenoma, and 105 age- and sex-matched control subjects were examined for H. pylori infection and histological gastritis. H. pylori status was evaluated by Giemsa staining and IgG serology. Mucosal inflammation, atrophy, and IM were evaluated in biopsy specimens from antrum and corpus.

RESULTS

H. pylori seroprevalence was higher in patients with gastric carcinoma (98 of 105, 93%) and adenoma (34 of 36, 94%) than in control subjects (82 of 105, 71%, p < 0.05). H. pylori was more prevalent in patients with noncardia (OR, 5.67; 95% CI, 2.25-14.44) than cardia (OR, 5.20; 95% CI, 0.65-41.68) tumors. Histologic types and tumor stage (early; OR, 6.60; 95% CI, 2.23-19.69, advanced; OR, 4.27; 95% CI, 1.21-15.03) showed no difference in H. pylori prevalence. Atrophy and IM scores were higher in patients with the intestinal- but not diffuse-type of carcinoma and adenoma than in H. pylori-positive control subjects. Smoking was associated with gastric carcinoma (OR, 3.05; 95% CI, 1.58-5.93) but not alcohol or coffee use, blood group A, or a family history of gastric cancer.

CONCLUSIONS

Our results confirm a strong association between H. pylori and gastric carcinoma and adenoma. The intestinal-type gastric carcinoma is associated with atrophic gastritis and IM.

Blood tests in the management of Helicobacter pylori infection. Italian Helicobacter pylori Study Group

There are three main types of blood test available for the management of Helicobacter pylori infection: those that detect an antibody response; tests of the pathophysiological state of the stomach; and those that indicate an active infection. Enzyme linked immunosorbent assay (ELISA) based kits are the most numerous of the commercially available tests. Originally the kits used crude antigen preparations but many of the newer kits use a more purified antigen preparation giving increased specificity but a lower sensitivity. The sensitivity, specificity, and predictive values of the tests can also be affected by the population under test and coexistent disease in the patients. Near patient test kits are based on either latex agglutination or immunochromatography. Generally, they have low sensitivities compared with laboratory tests. Commercial western blotting kits have also been developed and are used to detect the presence of specific virulence markers. The exact role of serology in the management of Helicobacter infection has still to be defined, although there is evidence that, used as a screening procedure, it can reduce endoscopy cost and workload. Gastrin and pepsinogen blood concentrations may provide valuable information on the pathophysiological state of the stomach--for example, the presence of inflammation or gastric atrophy. A combination of serology and serum concentrations of gastrin and pepsinogen may be used effectively to detect serious gastroduodenal disease in patients.

Helicobacter pylori and peptic ulcer disease. Current evidence for management strategies

OBJECTIVE

To review current evidence for primary care physicians who manage Helicobacter pylori in peptic ulcer disease.

QUALITY OF EVIDENCE

MEDLINE was searched to August 1997 for randomized controlled trials, systematic overviews, and consensus reports. High-quality recent reviews were often found. Randomized controlled trials presented as abstracts at recent meetings were reviewed.

MAIN FINDINGS

Helicobacter pylori is found in most case of duodental and gastric ulcer, and eradication of H pylori leads to "cure" of ulcer disease and prevention of ulcer complications. Eradication of H pylori is not indicated for gastroesophageal reflux disease. No evidence indicates that screening asymptomatic individuals for H pylori infection reduces the risk of subsequent development of gastric cancer. Controversial areas are the role of H pylori in functional dyspepsia and screening for H pylori before initiating nonsteroidal anti-inflammatory drugs. In primary care, H pylori can be detected using serologic tests or urea breath tests (UBT), but only UBTs can be used to confirm eradication. Whether patients suspected of having ulcers can be managed with an H pylori test-and-treat strategy without initial investigation is controversial. The first-line recommended treatment is 1 week of twice daily triple therapy with a proton pump inhibitor, clarithromycin (Biaxin), and amoxicillin (e.g., Amoxil), or metronidazole (Flagyl).

CONCLUSIONS

Helicobacter pylori eradication should be first-line therapy in primary care for infected patients with peptic ulcers. Effective H pylori testing methods and treatments are now available.

Testing for Helicobacter pylori in primary care: trouble in store?

STUDY OBJECTIVE

To assess the role of testing for Helicobacter pylori in the management of dyspeptic patients in primary care.

DESIGN

Selective review of literature frequently quoted to support use of H pylori testing.

MAIN RESULTS

Testing for H pylori and referral of only positive cases for endoscopy aims to reduce the number of "unnecessary" endoscopies. Patients with negative results may receive short-term reassurance and subsequently place fewer demands on health services. However, studies to date have only assessed this practice in secondary care settings. Given the relatively high prevalence of both dyspepsia and H pylori infection, the transfer of this practice to primary care may lead to a paradoxical increase in endoscopy referrals. Identification of H pylori and prescribing of eradication treatment also aims to reduce endoscopy referrals. No primary care trials have yet assessed this approach. Given that fewer than one in four of dyspeptic patients have peptic ulceration, a high proportion may fail to respond to eradication treatment and subsequently require referral for endoscopy. The longer term clinical and psychosocial sequelae of treating or labelling patients with an infection associated with gastric cancer remain unknown.

CONCLUSIONS

Given uncertainty concerning the possible adverse effects of H pylori testing in primary care, we suggest a moratorium on its use in this setting until results from relevant clinical trials become available.

Evaluation and comparison of two immunodiagnostic assays for Helicobacter pylori antibodies with culture results

Several commercially available serological kits have been used as an alternative to endoscopy for the diagnosis of Helicobacter pylori infection. We evaluated the performance of two such kits, Serion H. pylori immunotab kit (Serion, Wurzberg, West Germany) and Pyloragen H. pylori test kit (Hypcor Biomedical Inc., Irvine, CA). Gastric biopsy and serum samples were collected from 345 consecutive dyspeptic patients. The culture and or direct smear of the biopsy was positive for H. pylori in 228 patients (66%), whereas 117 patients (34%) were found to be H. pylori negative. We determined the serological response of the patients using the two kits, both of which are based on the principle of enzyme-linked immunosorbent assay. Comparing the serum immunoglobin G (IgG) and IgA (in a limited number of cases) responses to H. pylori status, the sensitivity, the specificity, positive predictive value, and negative predictive value were calculated. The corresponding data for the different tests were 64%, 79%, 84%, and 56% for Serion IgC, 32%, 94%, 88%, and 52% for Serion IgA, and 88%, 17%, 62%, and 46% for Pyloragen IgG, respectively. We conclude that there is a poor correlation between the presence of H. pylori infection and the antibody response, which could be explained either because of low sensitivities and specificities of the commercial kits used for the measurement of antibodies to H. pylori in the serum or because of poor immunological response in our patients to H. pylori antigens.

Comparison of rapid office-based serology with formal laboratory-based ELISA testing for diagnosis of Helicobacter pylori gastritis

Accurate and cost-effective diagnosis of Helicobacter pylori gastritis has taken on major importance. Several serologic tests for the diagnosis of H. pylori infection are commercially available. We compared the performance of the FlexSure HP rapid IgG antibody test with the conventional HM-CAP ELISA to evaluate whether qualitative office-based serology is reliable enough to replace formal laboratory-based testing. We assessed H. pylori status by concordance in 100 consecutive patients with antral biopsy, rapid urease, and 1 microCi[14C]urea breath tests. Both antibody tests had good sensitivity and specificity (>86%). Concordance between the two antibody tests occurred in 87/93 patients (94%). Based on our data, the office-based FlexSure HP performed equally well as the laboratory-based formal ELISA and may be a better choice for initial serologic diagnosis in untreated patients.

Helicobacter pylori independent chronological change in gastric acid secretion in the Japanese

BACKGROUND

Gastric acid secretion in Japanese subjects decreases with aging. One of the possible causative mechanisms of this attenuated acid secretion is speculated to be a Helicobacter pylori induced chronic gastritis. The infection rate of this microorganism has decreased recently in Japan.

AIMS

To investigate whether gastric acid secretion has altered over the past 20 years, and if so, what the influence of H pylori infection might be in the Japanese population.

SUBJECTS AND METHODS

Gastric acid secretion, serum gastrin and pepsinogen I and II concentrations, and H pylori infection were determined in 110 Japanese subjects in both the 1970s and 1990s.

RESULTS

Basal acid output as well as maximal acid output have greatly increased over the past 20 years, not only in individuals with H pylori infection but also in those without infection. Furthermore, subjects with H pylori infection tended to show decreased gastric acid secretion in comparison with those without infection, particularly in geriatric subjects. There was a positive correlation between gastric acid secretion and serum pepsinogen I concentrations.

CONCLUSIONS

In Japan, both basal and stimulated gastric acid secretion have increased over the past 20 years; some unknown factors other than the decrease in H pylori infection may play an important role in this phenomenon.

Seroprevalence and epidemiology of Helicobacter pylori infection in patients with cirrhosis

BACKGROUND

Helicobacter pylori infection is the major pathogenic factor for peptic ulcer disease. Its epidemiology is not fully known; few data are available in patients with chronic liver disease.

AIMS

To investigate the seroprevalence and factors associated with Helicobacter pylori infection in a series of liver cirrhosis patients.

METHODS

Two hundred and twenty consecutive patients were prospectively included in a study aimed to evaluate the effect of dietary intervention on cirrhosis complications and survival. At inclusion, an epidemiological and clinical questionnaire was completed. Sera were obtained and stored at -70 degrees C until analyzed. They were tested for Helicobacter pylori antibodies using a commercial ELISA kit.

RESULTS

Eleven out of 220 patients had borderline anti-Helicobacter pylori IgG titers. Of the remaining 209 patients, 105 (50.2%) showed positive titers of Helicobacter pylori IgG. Univariate analysis showed that Helicobacter pylori infection was more frequent in older patients, those born outside Catalonia, and in patients with a low educational level. Past ethanol consumption and current smoking correlated negatively with Helicobacter pylori infection. Multivariate analysis selected age (OR 3.1. 95% CI 1.46-6.45), educational level (OR 2.2. 95% CI 1.18-4.2) and alcohol consumption (OR 0.7. 95% CI 0.45-0.99) as the variables independently related to Helicobacter pylori infection.

CONCLUSIONS

Helicobacter pylori infection in cirrhosis has the same epidemiological pattern as in the general population. Suggestions that the etiology or the severity of the liver disease could be related to Helicobacter pylori infection were not confirmed by our study.

Diagnosis of Helicobacter pylori infection in a colony of rhesus monkeys (Macaca mulatta)

Twenty-three young adult rhesus monkeys from China were evaluated for the presence of Helicobacter pylori. Gastric body and antral biopsy samples were tested for H. pylori by PCR analysis, culture, rapid urease testing, and histologic evaluation. Serologic testing to detect H. pylori immunoglobulin G (IgG) antibodies was performed by using a commercially available human-based enzyme-linked immunosorbent assay (ELISA) test and an ELISA test which utilized homologous H. pylori antigens and an anti-rhesus IgG conjugate. PCR analysis with H. pylori-specific 26-kDa protein primers detected H. pylori in 21 of the 23 rhesus monkeys (91%). Culture testing identified the organism in 12 of the 23 animals (52%). Rapid urease tests were positive for all animals. H. pylori was diagnosed by histological examination in 11 of 23 monkeys (48%). Of the 21 monkeys positive for H. pylori by PCR, only 3 (14%) had positive results by the commercial ELISA test, yielding a sensitivity of 14%, a specificity of 100%, and an accuracy of 22%. However, 19 of the 21 PCR-positive animals (90%) had positive results by the ELISA test with homologous rhesus H. pylori antigen and anti-monkey conjugate, with predicted index values greater than or equal to 0.7 considered positive and values between 0.5 and 0.7 considered equivocal. This test had a sensitivity of 90%, a specificity of 100%, and an accuracy of 91%. Therefore, the ELISA test with rhesus monkey origin components was more accurate for detecting infected animals than the human-based ELISA.

Evaluation of initial noninvasive therapy in pediatric patients presenting with suspected ulcer disease

OBJECTIVE

To compare the clinical and economic effects of five likely treatment strategies in children with dyspepsia: initial diagnostic endoscopy (EGD) with biopsy for Helicobacter pylori infection; initial EGD without biopsy; H. pylori serology screening and treatment for H. pylori if positive; empiric treatment with antisecretory therapy; and empiric treatment for H. pylori with antibiotics and antisecretory therapy.

METHODS

Our decision analysis model incorporated data from published literature on the incidence of duodenal ulcer disease and effect of H. pylori infection. Cost inputs were derived from payments made by third-party payers. For the three noninvasive strategies that did not include immediate endoscopy, endoscopy was performed on the first episode of symptom recurrence.

RESULTS

The estimated costs per child evaluated for each strategy were: EGD with biopsy, $1458; EGD alone, $1248; H. pylori serology, $1224; antisecretory, $1160; and antisecretory-antibiotic, $1164. Results were sensitive to the costs of EGD and the likelihood of recurrent symptoms in children. When the cost of endoscopy fell below $950 or if over 65% of patients without ulcers eventually underwent endoscopy, there was no longer a cost advantage for initial noninvasive treatment when compared with EGD alone strategy.

CONCLUSION

In a decision analysis model, empiric antisecretory treatment in children with dyspepsia was most cost-effective, eliminating 40% of endoscopies and leading to antibiotic use in only those patients with H. pylori (4%). Further studies to determine the actual recurrence rate of symptoms after empiric antisecretory treatment of children with dyspepsia are required.

The application of epitope mapping in the development of a new serological test for Helicobacter pylori infection

Epitope mapping was applied to the derived amino acid sequences of the urease A and urease B genes of Helicobacter pylori. This identified 15 epitopes of which five were the most immunodominant. These were LTPKELD (Ure A), FISP, QIPTAF, EVGKVA and SIP (Ure B). Peptide 1 representing LTPKELD and peptide 2 representing EVGKVA were used to develop ELISA procedures for detecting antibody specific to H. pylori infection. The sensitivity, specificity and efficiency values for peptide 1 reactive IgM were 31.6, 92.8 and 52.5% and for peptide 1 IgG were 52.6, 35.7 and 45.4%. The corresponding values for peptide 2 IgM were 31.6, 100 and 60.6% and for peptide 2 IgG were 63.2, 71.4 and 66.6% respectively. When the tests were combined so that a positive for either peptide was counted as a positive overall the figures for IgM were 52.6, 92.8 and 69.6%. Thus epitope mapping delineated peptides against which specific IgM was produced in active H. pylori infection.

Evaluation of Pyloriset Dry, a new rapid agglutination test for Helicobacter pylori antibody detection

We evaluated the performance of a new latex agglutination test, Pyloriset Dry (Orion Diagnostica, Espoo, Finland), in the simultaneous detection of immunoglobulin G (IgG), IgA, and IgM antibodies to Helicobacter pylori and compared it with that of the Pyloristat test (BioWhittaker, Fontenay-sous-Bois, France), an enzyme-linked immunosorbent assay detecting IgG to H. pylori, for 96 untreated dyspeptic patients who had undergone gastroduodenal endoscopy. Infection was diagnosed in 56 cases by positive culture and/or positive Giemsa stain and rapid urease test (antral biopsies) and was associated with chronic gastritis in 52 patients. Forty noninfected patients did not have chronic gastritis. The sensitivity of Pyloriset Dry was 91.1%. The sensitivity of Pyloristat was 91.1 or 82.1%, depending on whether equivocal results were considered positive or negative, respectively. Both tests had a specificity of 87.5%. Their performances were not statistically different. Thus, Pyloriset Dry is an alternative to serological tests for adults, particularly when a small number of serum samples has to be tested.

Evaluation of three commercial enzyme immunoassays compared with the 13C urea breath test for detection of Helicobacter pylori infection

The diagnostic significance of the serological detection of antibodies to Helicobacter pylori has been established by numerous investigators. Reports of the clinical reliabilities of commercial enzyme immunoassay (EIA) kits available for this purpose vary as a result of the different H. pylori antigen sources and reference methods used. The 13C urea breath test (UBT) has been shown to be an extremely accurate and reliable method of detecting H. pylori infection. We used the 13C urea breath test as the confirmatory method for H. pylori status to evaluate three commercially available EIA kits designed to detect immunoglobulin G antibodies to H. pylori. These kits were the HM-CAP EIA kit (Enteric Products, Inc.), the PYLORI STAT EIA kit (BioWhittaker, Inc.), and the G.A.P. kit (Bio-Rad Laboratories/Biomerica, Inc.). The evaluations were performed in a double-blind manner with samples from 473 clinically characterized patients. This group included patients with symptomatic gastrointestinal disorders as well as nonsymptomatic volunteers. The sensitivities of the kits were as follows: HM-CAP, 98.4%; PYLORI STAT, 99.2%; and G.A.P., 100%. The specificities were as follows: HM-CAP, 96.4%; PYLORI STAT, 90.1%; and G.A.P., 26.0%. Although the HM-CAP and PYLORI STAT kits performed comparably, the G.A.P. test yielded significantly more false-positive results and an unacceptably high number of indeterminate results.

Accuracy of serology for the diagnosis of Helicobacter pylori infection--a comparison of eight kits

AIMS

To determine the accuracy of eight commercially available kits for the serological diagnosis of Helicobacter pylori infection, and hence whether a serology service could be introduced to reduce endoscopy workload.

METHODS

Eighty four patients newly presenting to their general practitioners with dyspepsia were recruited. Gold standard diagnosis of H pylori infection was obtained both by a histological examination of gastroduodenal biopsy specimens and by the 14C-urea breath test (UBT). The performance of six quantitative and two qualitative enzyme linked immunosorbent assays for H pylori IgG, used according to the manufacturers' instructions, with serum samples obtained during the endoscopy visit, were compared.

RESULTS

The study population had a median age of 45 years, and the prevalence of H pylori infection was 35%. With one exception, where the patient had received a course of anti-H pylori treatment between endoscopy and UBT, there was 100% concordance in the results of the two gold standard techniques. Discordant serology results were more common in patients aged > 50 years (42% of the total) than in younger patients (21%), and this was most noticeable in uninfected patients. The sensitivity of the kits was good (90-100%), but specificity was more variable (76-96%), and the rate of equivocal results was unacceptably high in some cases (0-12%). The overall accuracy of the kits ranged from 83 to 98%. Two kits in particular performed well (Pylori-Elisa II, Bio-Whitaker and Premier, Launch; qualitative) with 98% and 100% accuracy, respectively.

CONCLUSIONS

In a symptomatic population with a prevalence of H pylori infection of 35%, particularly in patients aged < 50 years, some but not all serology kits may be used as a highly accurate and inexpensive alternative to the gold standard techniques.

New noninvasive tests for Helicobacter pylori gastritis. Comparison with tissue-based gold standard

The current gold standard for diagnosing H. pylori gastritis requires antral biopsy for urease test (eg, CLOtest) and/or history. We compared this gold standard to a new low-dose capsule-based 1 microCi [4C]urea breath test (UBT) and a rapid serum test for anti-H. pylori antibodies (FlexSure HP) in 50 consecutive patients undergoing upper endoscopy. Antral biopsies within 3 cm of the pylorus were used for CLOtest and were stained with H&E and thiazine. Slides were reviewed by a single, blinded pathologist (Review) and compared to the pathology department report (Report). A true positive was defined as a positive CLOtest or Review. The prevalence of H. pylori infection by each test was: CLOtest 32%, Review 36%, gold standard 42%, UBT 38%, FlexSure HP 44%, Report 44%. UBT had sensitivity = 90%, specificity = 96%, positive predictive value = 95%, and negative predictive value = 93% and accurately determined H. pylori status in a subgroup of 10 patients who had completed treatment. The one false positive breath test occurred in a patient with 2+ chronic inflammation on biopsy and a positive antibody test. There were two false negative breath tests. Each had both negative CLOtests and negative antibody tests. FlexSure HP had sensitivity = 74%, specificity = 89%, positive predictive value = 88%, and negative predictive value = 77% in patients not previously treated, but had a high false-positive rate in the 10 patients after treatment. Pathology department Report and blinded pathologist Review had only 84% agreement, kappa = 0.67. Both CLOtest and UBT agreed better with Review (86%, 87%, kappa = 0.68, 0.73, respectively) than Report (78%, 77%, kappa = 0.53, 0.53, respectively) suggesting that Review is more accurate than Report. When biopsy is done, we recommend that a CLOtest be performed followed by histological examination if the CLOtest is negative to ensure adequate sensitivity. However, interpretation of histological slides has significant interobserver variability even in experienced hands and may be inaccurate at times. FlexSure HP has good PPV but inadequate sensitivity to rule out active infection and is not useful in patients after treatment. UBT is an excellent noninvasive test that should be considered in cases where EGD is otherwise not indicated.

Evaluation of enzyme immunoassay for detection of salivary antibody to Helicobacter pylori

The Helisal test is a quantitative enzyme immunoassay for the measurement of Helicobacter pylori-specific immunoglobulin G antibodies in saliva. This test was evaluated in comparison with culture and histopathologic examination of gastric biopsy specimens obtained from 195 patients who underwent 200 endoscopic procedures for the investigation of gastrointestinal symptoms. Forty-one (21%) patients were found to have peptic ulcer disease, and one other patient had a gastric carcinoma. H. pylori was detected in gastric biopsy specimens obtained from 98 (49%) of the procedures. The sensitivity, specificity, and positive and negative predictive values of the Helisal test were 81, 75, 76, and 80%, respectively. The test was negative for 16 (38%) of the 42 patients with peptic ulcer disease or a gastric malignancy diagnosed at endoscopy. These results suggest that the Helisal assay is only moderately accurate for the detection of H. pylori infection in symptomatic patients.

Immediate endoscopy or initial Helicobacter pylori serological testing for suspected peptic ulcer disease: estimating cost-effectiveness using decision analysis

OBJECTIVE

To compare the clinical and economic effects of a strategy using immediate endoscopy to a non-invasive strategy utilizing a serologic test for Helicobacter pylori infection for individuals with symptoms suggestive of peptic ulcer disease.

DESIGN

Cost-effectiveness analysis evaluating the clinical and economic effects of alternative management strategies of hypothetical patients with suspected peptic ulcer disease in a computer simulation model.

INTERVENTION

Two strategies for hypothetical patients with suspected ulcer disease were evaluated: 1) Immediate endoscopy and biopsy for H. pylori, using antisecretory treatment in all patients with documented ulcers and adding antibiotic eradication therapy for those patients with ulcers whose biopsies were positive for H. pylori. 2) Empiric treatment with antisecretory therapy and serologic testing for H. pylori for all patients, using antibiotic eradication therapy only in patients testing positive for H. pylori.

MEASUREMENTS

Cost per ulcer cured over a one-year study period.

RESULTS

The more cost-effective strategy was the test-and-treat strategy (Strategy 2) with $4481 cost per ulcer cured. The immediate endoscopy strategy resulted in $8045 cost per ulcer cured. The cost-effectiveness advantage of the non-invasive strategy diminished as the cost of endoscopy fell or as the probability of recurrent symptoms rose in patients initially managed without endoscopy.

CONCLUSION

Endoscopy, though costly, precisely guided diagnosis and treatment and, thus, potentially reduced the number of patients inappropriately treated. However, cost-effectiveness analysis supports the continued practice of initial non-invasive management of patients with symptoms suggestive of peptic ulcer disease, achieving the benefits of H. pylori eradication through the use of serologic testing to guide antibiotic use.

Helicobacter pylori in endoscopy patients in Zimbabwe: value of enzyme-linked immunosorbent assay and a rapid urease test

Biopsy and serum specimens were obtained from 95 patients undergoing endoscopy at the University of Zimbabwe Medical School. Common presenting features were epigastric pain, bleeding and dyspepsia. Ulcers were detected in 16 patients (17%), and were more common in men (24%) than in women (7%). Histological examination of biopsies showed that all 95 patients had spiral-shaped organisms that were indistinguishable microscopically from Helicobacter pylori, though the numbers of organisms varied considerably. There was evidence that the degree of inflammation in the mucosa was related to the numbers of H. pylori-like organisms (HPLO) present. Fifty-one biopsy specimens (55%) gave a positive rapid urease test (RUT), with colour change occurring within 4 h. In all but one case, the gastric mucosa from these patients contained moderate to numerous HPLO. We defined the 'gold standard' of H. pylori-associated gastritis as the presence of both moderate to numerous HPLO and moderate to severe inflammation in the gastric mucosa. Using these criteria, RUT had a sensitivity of 67% and a specificity of 68%. Sera from 92 patients were tested for immunoglobulin G antibodies reactive with a glycine-extract antigen of H. pylori, using an enzyme-linked immunosorbent assay (ELISA). Sera giving an indeterminate reaction in the ELISA were also tested by Western blotting. In all, 36 sera (39%) gave a positive ELISA or Western blot reaction. There was poor correlation between serology and RUT results, with only 57% of biopsy specimens from seropositive patients giving a positive RUT, compared with 45% from seronegative patients. Positive serology was found in only 35 patients (61%) with histological evidence of H. pylori-associated gastritis, and the specificity of the test was only 54%. When used in combination with the RUT result, however, 79% of patients with a positive RUT and positive serology had histological evidence of H. pylori-associated gastritis. There was a general trend for increased seroprevalence in patients with mild to moderate atypia. These findings indicate that serology, using an antigen derived from the type strain of H. pylori, is unreliable in detecting H. pylori infection in Zimbabwe. Current studies are aimed at characterizing antigens from organisms isolated from Zimbabwean patients.

Multi-laboratory comparison of eight commercially available Helicobacter pylori serology kits. Helicobacter pylori Serology Study Group

The performance of eight commercially available EIA kits in detecting antibody to Helicobacter pylori was evaluated by a panel of 17 laboratories using serum from 59 patients selected from endoscopy clinics in Belgium, Ireland, Italy, the Netherlands and Switzerland. Each laboratory received a randomly numbered set of sera and was ignorant of the culture results of the patients. The performance of the kits was assessed in terms of diagnostic accuracy compared to culture (measured by sensitivity and specificity), the inter-laboratory variability in diagnostic accuracy and the number of laboratories that experienced problems in using the kits. Grey zone results, which are routinely used to highlight the uncertain interpretation of results that lie near the cut-off point between positive and negative diagnoses, were accounted for in the analysis. Laboratories experienced practical problems in using some kits, whilst other kits were found to have high inter-laboratory variation or low diagnostic accuracy. There was no single kit that performed better on every criterion than the others. The Orion kit was a good all-round performer, whilst the Roche kit was excellent at detecting positive results, although it had a slightly raised false-positive rate.