Oral fluid antibody detection in the diagnosis of Helicobacter pylori infection.

The aim of this study was to evaluate an enzyme-linked immunosorbent assay (ELISA) for the detection of anti-Helicobacter pylori specific IgG antibodies in specimens of oral fluid. Antral biopsy specimens, serum and oral fluid samples were collected from 81 patients attending for upper gastrointestinal endoscopy. The presence or absence of current H. pylori infection was determined by culture, histology and urease detection. Anti-H. Pylori specific IgG was detected in serum by an established in-house ELISA and in oral fluid by an ELISA developed for this study. In all, 34 (42%) of 81 patients were positive for H. pylori by one or more of the 'gold standard' tests (culture, histology and urease detection). The oral fluid ELISA had a sensitivity of 94% and specificity of 85% with regard to current H. pylori infection. The serum ELISA had a sensitivity and specificity of 91%. There was an overall agreement of 88% between serum and oral fluid antibody detection. The detection of anti-H. pylori specific IgG in oral fluid by ELISA is comparable in sensitivity and specificity with serum-based methods. Oral fluid-based ELISA could provide a reliable, non-invasive method for the diagnosis of H. pylori infection, and may be of particular benefit for population surveys.     

Peptic ulcer disease and neuroticism in the United States adult population

BACKGROUND: The goal of the current study was to determine the association between personality factors and peptic ulcer disease (PUD) among adults in the general population. METHOD: Data were drawn from the Midlife Development in the United States Survey (MIDUS), a representative household survey of the adult population (ages 25-74; n = 3,032) of the United States. Multiple logistic regression analyses were used to determine the association between the big five personality factors and PUD, adjusting for differences in sociodemographic characteristics, psychiatric and physical comorbidity. RESULTS: Neuroticism was associated with significantly increased odds of PUD [OR = 1.5 (95% CI: 1.03, 2.4)], which persisted after controlling for differences in sociodemographic characteristics, cigarette smoking, perception of poor health, comorbid mental disorders and physical illnesses. This relationship was specific to neuroticism. CONCLUSIONS: These findings are consistent with and extend previous clinical and epidemiologic data by providing evidence of an independent association between neuroticism and PUD among adults in the general population. Future work investigating the relationship between neuroticism and the development of PUD in prospective data, including objective measures of physical and mental health status, may contribute to our understanding of this association.     

Helicobacter pylori in a costa rican dyspeptic patient population

Gastric biopsies from 65 Costa Rican dyspeptic patients were investigated for the presence ofHelicobacter pylori DNA by polymerase chain reaction (PCR) amplification of 16S rRNA sequences. Both frozen and paraffin-embedded samples were used, and the results were compared with bacterial culture and histological examination.Helicobacter pylori DNA was detected by PCR in 60 (92 %) of the patients, andHelicobacter pylori strains confirmed by PCR could be isolated from 37 of them. Altogether, 59 patients were shown to be infected using the combination of culture and histology as the reference method. The sensitivity of PCR analysis of frozen material was 98 % (58/59). The PCR analysis of paraffin-embedded samples seemed less reliable than that of frozen biopsy material.     

Host Cell Responses to Genotypically Similar Helicobacter pylori Isolates from United States and Japan

Associations of Helicobacter pylori genotypes with disease differ between Western countries and Asia. Therefore, we directly compared histopathological and in vitro responses to clinical isolates with similar genotypes. Sixty-three cagA⁺ vacAs1/m1 H. pylori isolates (United States, n = 24; Japan, n = 39) and eight cagA-negative vacAs2/m2 strains were incubated with AGS cells, and supernatants were assayed for interleukin-8 (IL-8) and for DNA fragmentation. CagA tyrosine phosphorylation in AGS cells and the sequence of the putative HP0638 (oipA) signal sequence region were determined for 22 representative strains. HP0638 and/or cag island mutant strains were created and examined in IL-8 and CagA tyrosine phosphorylation assays. Levels of IL-8 induction and DNA fragmentation were similar in the U.S. and Japanese cagA⁺ vacAs1/m1 isolates. All 10 of the isolates with the highest IL-8 induction and 8 of the 10 isolates with the lowest IL-8 induction had an in-frame oipA open reading frame, and all 10 of the isolates with the highest IL-8 induction and 7 of the 10 isolates with the lowest IL-8 induction induced CagA tyrosine phosphorylation in AGS cells. Eight isolates from gastric ulcer patients induced significantly more apoptosis in vitro, and more severe gastritis and atrophy in vivo, than other Japanese isolates. Disruption of HP0638 did not affect IL-8 induction or CagA tyrosine phosphorylation. Thus, H. pylori cagA⁺ vacAs1/m1 isolates from the United States and Japan induce similar IL-8 and apoptosis levels. Inactivation of HP0638 does not alter epithelial responses mediated by the cag island in vitro. Assessment of apoptosis in vitro identified a group of H. pylori isolates that induce more severe gastric inflammation and atrophy.     

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.     

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.     

Helicobacter pylori Virulence Factor Genotypes in Children in the United States: Clues about Genotype and Outcome Relationships

The most common Helicobacter pylori genotype among 37 U.S. children was cagA positive, vacA s1m1, and oipA “on” (n = 17, 45.9%), followed by cagA negative, vacA s2m2, and oipA “off” (n = 8, 21.6%), similar to the pattern in adults. cagA positivity was more common in blacks than in whites (i.e., 100% versus 56.5%, P = 0.032).Infection with Helicobacter pylori is etiologically associated with gastritis, peptic ulcer disease, gastric atrophy, and gastric cancer. H. pylori is thought to be typically acquired in childhood, with infection continuing for decades if not lifelong. This long bacterial host association involves countless generations of bacteria which are thought to continually evolve as the intragastric conditions change, such that those best suited for the local conditions outgrow and replace less suited neighbors. There has been considerable interest in the molecular epidemiology of H. pylori''s putative virulence factors, especially CagA, VacA, and OipA (outer inflammatory protein A) (8, 11, 12). However, there are few studies of children and only one previous study investigating the relationship between H. pylori virulence factors and ethnic groups of children in the United States (4-6, 11). This study reports the patterns of H. pylori virulence factor genotypes in children of different ethnic groups in the United States.The biopsy specimens and cultures were obtained as part of a multicenter study from 5 widely dispersed sites in the United States. The study was designed to validate the [¹³C]urea breath test for the diagnosis of H. pylori infection in children aged between 2 years and 17 years and 11 months (2). Symptomatic children scheduled for endoscopy were enrolled. Gastric biopsy specimens were evaluated by histology, rapid urease testing, and culture of H. pylori using established techniques (2). H. pylori culture isolates were evaluated for cagA and vacA genotypes using established PCR assays as previously described (9). The number of EPIYA (Glu-Pro-Ile-Tyr-Ala) repeat motifs in the 3′ region of the cagA gene was evaluated using PCR as previously described (7). OipA is a member of the large outer membrane protein family whose functional status is regulated by slipped-strand mispairing based on the number of CT dinucleotide repeats in the 5′ region of the gene (a switch status of “on” indicates the gene is functional, and a switch status of “off” indicates it is nonfunctional) (10). The 5′ region of the oipA gene was amplified using previously described primers (10), and the PCR fragments were purified and directly sequenced at Macrogen, Ltd., in Seoul, South Korea.Forty-eight of 176 children enrolled were H. pylori infected, based on two positive tests or a positive H. pylori culture. The mean age was 11.5 years (range, 3.2 to 17.9 years). Thirty-seven were H. pylori culture positive. None had atrophic gastritis. Only one patient had a significant endoscopic abnormality, a duodenal ulcer (cagA positive, vacA s1m2, and oipA on). The most common H. pylori genotype was cagA positive, vacA s1m1, and oipA on (n = 17, 45.9%), followed by cagA negative, vacA s2m2, and oipA off (n = 8, 21.6%), cagA positive, vacA s1m2, and oipA on (n = 5), cagA positive, vacA s1m1, and oipA on (n = 3), cagA negative, vacA s2m2, and oipA on (n = 2), cagA negative, vacA s1m1, and oipA on (n = 1), and cagA positive, vacA s1m2, and oipA off (n = 1) (Table ​(Table1).1). Overall, 70% of strains were cagA positive, which is similar to is the proportion found in U.S. adults (6).

TABLE 1.

Relationship between H. pylori genotype and ethnic group

Host cell responses to genotypically similar Helicobacter pylori isolates from United States and Japan.

Associations of Helicobacter pylori genotypes with disease differ between Western countries and Asia. Therefore, we directly compared histopathological and in vitro responses to clinical isolates with similar genotypes. Sixty-three cagA(+) vacAs1/m1 H. pylori isolates (United States, n = 24; Japan, n = 39) and eight cagA-negative vacAs2/m2 strains were incubated with AGS cells, and supernatants were assayed for interleukin-8 (IL-8) and for DNA fragmentation. CagA tyrosine phosphorylation in AGS cells and the sequence of the putative HP0638 (oipA) signal sequence region were determined for 22 representative strains. HP0638 and/or cag island mutant strains were created and examined in IL-8 and CagA tyrosine phosphorylation assays. Levels of IL-8 induction and DNA fragmentation were similar in the U.S. and Japanese cagA(+) vacAs1/m1 isolates. All 10 of the isolates with the highest IL-8 induction and 8 of the 10 isolates with the lowest IL-8 induction had an in-frame oipA open reading frame, and all 10 of the isolates with the highest IL-8 induction and 7 of the 10 isolates with the lowest IL-8 induction induced CagA tyrosine phosphorylation in AGS cells. Eight isolates from gastric ulcer patients induced significantly more apoptosis in vitro, and more severe gastritis and atrophy in vivo, than other Japanese isolates. Disruption of HP0638 did not affect IL-8 induction or CagA tyrosine phosphorylation. Thus, H. pylori cagA(+) vacAs1/m1 isolates from the United States and Japan induce similar IL-8 and apoptosis levels. Inactivation of HP0638 does not alter epithelial responses mediated by the cag island in vitro. Assessment of apoptosis in vitro identified a group of H. pylori isolates that induce more severe gastric inflammation and atrophy.     

Evaluation of commercial immunoassays for detection of antibody against Helicobacter pylori in Thai dyspeptic patients

The performance of five immunoassays for detection of immunoglobulin G antibody against Helicobacter pylori in 191 dyspeptic patients was evaluated. The sensitivities, specificities, accuracies, positive predictive values, and negative predictive values ranged from 86.32 to 97.89%, 57.95 to 72.22%, 77.02 to 83.76%, 71.54 to 77.42%, and 83.33 to 96.23%, respectively. The immunoglobulin A test kit also gave a high sensitivity and negative predictive value (95.79 and 91.40%, respectively), while the specificity was relatively low (51.14%).     

Helicobacter pylori infection in an urban African population

We have studied 221 adults drawn from an impoverished urban population with high human immunodeficiency virus (HIV) seroprevalence (35%) to determine the prevalence of gastroduodenal pathology and its relationship to serological markers of Helicobacter pylori virulence proteins and other potential environmental and immunological determinants of disease including HIV infection. Eighty-one percent were H. pylori seropositive, and 35% were HIV seropositive. Urban upbringing and low CD4 count were associated with a reduced likelihood of H. pylori seropositivity, as was current Ascaris infection, in keeping with recent evidence from an animal model. One hundred ninety-one adults underwent gastroduodenoscopy, and 14 had gastroduodenal pathology. Mucosal lesions were a major cause of abdominal pain in this population. While the majority of patients with gastroduodenal pathology (12 of 14) were seropositive for H. pylori, none were seropositive for HIV. Smoking was associated with increased risk of macroscopic pathology, and a history of Mycobacterium bovis BCG immunization was associated with reduced risk. Antibodies to H. pylori lipopolysaccharide were associated with pathology. HIV infection was associated with protection against mucosal lesions, suggesting that fully functional CD4 lymphocytes may be required for the genesis of gastroduodenal pathology.     

Seroprevalence of Helicobacter pylori infection in Malagasy population

Helicobacter pylori is a worldwide infection. However very few data are actually available on H. pylori seroprevalence in the Malagasy population. We carried out a transversal study in a sample of persons who met the following criteria: older than 15 years old, presence in the medicine internal unit 2 (University Hospital Center of Antananarivo) during the period of the study whatever the reason. H. pylori infection was identified serologically by using ELISA (G.A.P IgG H. pylori ELISA, Bio-Rad, France). Several factors were evaluated including serological status, demographic information, the reason of the presence in the unit, factors influencing H. pylori infection: socio-economic status, siblings, promiscuity consumption of alcohol, use of tobacco, water source and history of gastroscopy. The presence of clinical symptoms, such as dyspepsia and abdominal pain, was determined. Forty-five men and 45 women were included (mean age: 41.8 +/- 3.4 years). The seroprevalence of H. pylori infection was 82%. H. pylori infection was higher in men than in women (p < 0.02). Promiscuity constituted the principal factor influencing H. pylori infection. The seroprevalence of the H. pylori infection appears to be comparable to the rate encountered in developing countries. Considering this high rate of the H. pylori infection, eradication of H. pylori should be commonly recommended when facing gastrointestinal pathologies potentially induced by H. pylori.     

A practical single sample dry latex agglutination test for Helicobacter pylori antibody detection.

Assessment of a single serum sample for Helicobacter pylori antibodies is frequently requested in routine diagnostic laboratories. Current enzyme linked immunosorbent assay (ELISA) kits are not ideal for testing small numbers of serum samples and some have low sensitivities, specificities or large grey zones. A panel of 90 serum samples from patients who had presented for routine upper endoscopy was used to compare three kits for the detection of H pylori antibodies: (1) Pyloriset Dry, total antibody latex agglutination, Orion Diagnostica, Espoo, Finland; (2) Pyloriset enzyme immunoassay (EIA), IgG ELISA, Orion; and (3) Hel-p, IgG ELISA, Amrad, Kew, Victoria, Australia. Diagnosis of H pylori positivity was made if culture results and either rapid urease test or histopathology were positive. The sensitivity, specificity, positive, and negative predictive value for each test was as follows: Orion: latex 93.3%, 95.6%, 95.5%, 93.3%, respectively; Orion: EIA-G 84.4%, 97.8%, 97.4%, 84.4%, respectively; and Amrad: EIA-G 100%, 88.9%, 90%, 100%, respectively. The latex test performed better than the EIAs with respect to sensitivity and specificity.     

Immunohistochemical detection of Helicobacter pylori with a novel monoclonal antibody: Its clinicopathological significance and validity in the routine pathological diagnosis

The immunological mechanism of Helicobacter pylori-induced chronic gastritis is still unknown. In our previous study using a novel anti-H. pylori monoclonal antibody and surgically resected stomachs from gastric cancer patients, we succeeded to detect H. pylori captured by macrophages in gastric lamina propria and lymph nodes, and proved that the H. pylori-positive macrophages correlated with chronic gastritis. To elucidate this correlation in the cases without gastric cancer, we examined H. pylori in 519 gastric biopsy specimens of 242 cases using immunohistochemistry with the novel antibody. Also, we evaluated the validity of the novel antibody in the routine pathological diagnosis. In 402 specimens from the cases without gastric tumors, the bacteria were detected not only in the mucous layer of 148 specimens but also in the lamina propria of 144 specimens. The specimens only with the intramucosal bacteria showed high-grade chronic and low-grade acute inflammation, whereas the specimens only with the intra-mucous bacteria tended to show the low-grade chronic and high-grade acute inflammation. Statistically, H. pylori in the lamina propria correlated with chronic gastritis. When compared to commercially available anti-H. pylori antibody and Giemsa staining, the novel antibody showed the highest sensitivity to detect the bacteria in the lamina propria. These results suggest that H. pylori in the lamina propria is thought to be deeply related with the development of H. pylori-induced chronic gastritis also in the cases without gastric cancer. And, the novel antibody is proved to be very useful in the routine pathological assessment of H. pylori infection.     

Evaluation of a new immunodiagnostic assay for Helicobacter pylori antibody detection: correlation with histopathological and microbiological results.

Infection with Helicobacter pylori has been associated with the pathogenesis of chronic active gastritis and gastric and duodenal ulcer disease. Detection of immunoglobulin G antibodies to H. pylori offers a simple alternative to direct detection of the organism in biopsied tissue by culture or histopathological methods. A rapid flow-through membrane-based enzyme immunoassay for the detection of human immunoglobulin G antibodies to H. pylori has been developed and evaluated. Clinical evaluations were performed with 256 patient serum samples obtained from four clinical sites. Biopsy samples were obtained by endoscopic procedures at the same time as the serum samples, and were histopathologically and microbiologically categorized for the presence or absence of H. pylori. Sensitivity and specificity for this rapid enzyme immunoassay were 92 and 88%, respectively, compared directly with endoscopy results. After discordant results were resolved by a quantitative microwell enzyme-linked immunosorbent assay, the resulting sensitivity and specificity were 94 and > 99%, respectively. These results indicate that this rapid enzyme immunoassay is a useful technique to determine H. pylori infection status and is a viable alternative to invasive endoscopic procedures.     

Sensitivity of a novel stool antigen test for detection of Helicobacter pylori in adult outpatients before and after eradication therapy

We investigated whether a novel monoclonal stool antigen test for detection of Helicobacter pylori performs with the same accuracy as the (13)C-urea breath test (UBT) for adult outpatients in the setting of a private office. The two tests showed identical levels of sensitivity when used to identify H. pylori-infected patients before and after eradication therapy.     

Detection of Helicobacter pylori in stomach tissue by use of a monoclonal antibody.

Monoclonal antibodies were produced against an acid glycine extract of Helicobacter pylori ATCC 43504T. One of these appeared to be specific for H. pylori; it recognized all H. pylori isolates by an indirect immunofluorescence assay (IIF) but it did not cross-react with the other strains tested, including different species of the genera Helicobacter, Campylobacter, and Wolinella. Different strains of members of the families Enterobacteriaceae and Pseudomonadaceae or other gram-negative bacteria tested also gave negative reactions. Indirect immunofluorescence assay of antral biopsy specimens identified 54 of 56 infected patients (96.4%), and it may be able to detect nonviable organisms after antibiotic therapy.     

Use of the Optum Labs Data Warehouse To Assess Test Ordering Patterns for Diagnosis of Helicobacter pylori Infection in the United States

We surveyed national Helicobacter pylori diagnostic testing practices and diagnoses using commercial and Medicare medical claims data from Optum Labs (Cambridge, MA). Serologic testing for antibodies to H. pylori remains the most commonly ordered diagnostic test despite recent expert recommendations. Changes in reimbursement for serologic testing will likely drive future provider ordering practices.     

Correlation of serum antibody titres with invasive methods for rapid detection of Helicobacter pylori infections in symptomatic children

Helicobacter pylori (H. pylori) is causally associated with peptic ulcer disease and gastric carcinoma. Typically, children get infected during the first decade of life, but diseases associated with H. pylori are seen mainly in adults. Multiple diagnostic methods are available for the detection of H. pylori infection. The aim of this study was to evaluate the correlation and diagnostic accuracy of three invasive methods [rapid urease test (RUT), histology and bacterial culture] and one non-invasive method (IgG serology) for diagnosis of H. pylori infection in a prospective cohort study conducted on 50 symptomatic children between two and eighteen years of age. Endoscopies with gastric biopsies were performed for RUT, culture and histopathological examination, respectively. IgG antibodies were measured in patient sera using a commercially available enzyme-linked immunosorbent assay (ELISA). RUT and positive H. pylori IgG antibodies were concordant in 88% (44/50) of patients. Both tests were negative in 32% (16/50), and both were positive in 56% (28/50). Disagreement occurred in 12% (6/50) of the patients: three of them (6%) had positive RUT and negative H. pylori IgG, and another three (6%) had negative RUT and positive H. pylori IgG. A combination of RUT with non-invasive serology constituted the optimum approach to the diagnosis of H. pylori infection in symptomatic children. The non-invasive serological test (ELISA) could not be used alone as the gold standard because it cannot distinguish between active and recently treated infection; and bacterial culture could not be used alone because of its low sensitivity.     

High-resolution HLA alleles and haplotypes in the United States population

We extract and present high-resolution HLA allele and haplotype frequency data available from the National Marrow Donor Program databases from four major U.S. census categories of race and ethnicity. Population-based high-resolution HLA frequencies defined on the basis of from one to five loci are presented and made available online (http://bioinformatics.nmdp.org/haplotype2006). In addition, a discriminatory classification of HLA allelic variation on the basis of observed population allele frequencies (common, rare and unseen) for HLA A, C, B, DRB1, DQA1, and DQB1 is introduced. The electronic availability of this information will be useful for projects central to the typing and use of population data in HLA applications.