Non-invasive diagnosis of H pylori infection: Evaluation of serological tests with and without current infection marker CIM

Role of H.pylori in Chronic Sore Throat by Using H.pylori Line

Pharyngitis is an inflammation of the mucous membranes of the oropharynx. Pharyngitis may be caused by an infectious or noninfectious disease. Noninfectious diseases of pharynx include allergies, trauma, cancer, reflux and certain toxins. Infection with H. Pylori is associated with developing chronic sore throat, gastritis, gastric or duodenal ulcer, gastric cancer and MALT lymphoma. There are many different investigations to diagnose H pylori as H pylori antigen in blood and stool, urea breath test but, H. Pylori line is a new test for detection of the virulent strains. There are many lines of H pylori therapy in the form of PPIs and antibiotics for about two weeks. This study aimed to detect role of H pylori in chronic pharyngitis. 85 patients who had chronic pharyngitis with normal CBC, WBCS, lymphocyte, monocyte and eosinophils with negative ASO titer and throat swab. These patients did H pylori line to detect H pylori virulent antigen. 77 patients with chronic pharyngitis are positive H pylori and after medical treatment 68 patients became negative. H. Pylori line is a new test for detection of the virulent strains and screening H pylori carrier at risk of developing gastric and duodenal ulcers as well as cancer.

Frequency, distribution and determinants of Helicobacter pylori infection in adults and adolescents with gastric symptoms: cross-sectional epidemiological inquiry in district Haripur, Pakistan

Abstract Helicobacter pylori (HP) is a vital element in the etiology of peptic ulcers and gastric cancer. This research aimed to determine the frequency, distribution, and determinants of HP infection in adults and adolescents with gastric symptoms in district Haripur, Khyber Pakhtunkhwa, Pakistan. This cross-sectional study was performed from June 2018 to June 2020 at the Medical Laboratory Technology Department, The University of Haripur, Pakistan. Presence of HP was a research variable, while sex, age groups, education status, overcrowding, dining habits, milk intake, drinking water source and animal contact were grouping variables. Immuno-chromatographic technique (ICT) was used to for serological detection of HP antibodies. All variables were represented by frequency and percentage with 95%CI. Prevalence of HP and its distribution by eight socio-demographic variables was testified by the chi-square goodness-of-fit test while association was testified by chi-square test of association. Out of total 1160 cases, 557 (48%) were positive for HP. Population prevalence was higher in men, in the age group 20-40 years, illiterate, family size ≤ 10 persons, taking restaurant food, using tetra pack, using municipal water, and having animal contact. The observed prevalence of HP was similar to its expected prevalence in the population. The observed distribution of HP in the sample was different from its expected distribution in population by eight socio-demographic variables. Presence of HP was associated with all eight socio-demographic variables besides age groups.

Diagnostic Validity of a Serological Test with the Current Infection Marker in Thai Adults before and after Helicobacter pylori Eradication Therapy

Helicobacter pylori infection poses significant health risks, such as gastric adenocarcinoma, necessitating accurate diagnosis and effective treatment in primary care. This study evaluated the diagnostic efficacy of the serological current infection marker (CIM) test in identifying current H. pylori infection. The CIM test samples from 159 participants undergoing gastroscopy were collected, and H. pylori-positive outpatients received triple therapy based on histology or rapid urease test results. Following treatment, 45 patients underwent a 13C-urea breath test and the CIM test for eradication assessment. For pre-eradication, the CIM test demonstrated 89.6% sensitivity, 95.7% specificity, 93.8% positive predictive value, 92.6% negative predictive value, and 93.1% accuracy. Following post-eradication, the CIM test exhibited sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of 71.4%, 92.1%, 62.5%, 94.6%, and 88.9%, respectively, using the 13C-urea breath test as the reference standard. The CIM test showcased commendable diagnostic performance, emphasizing its efficacy in both pre- and post-eradication scenarios. Notably, the accuracy, non-invasiveness, user-friendliness, and cost-effectiveness of the CIM test advocate for its recommendation as a preferred diagnostic tool in primary care settings for H. pylori infection detection.

Thin Layer Immunoassay: An Economical Approach to Diagnose Helicobacter pylori Infection in Gastroduodenal Ulcer Disease Patients of Pakistan, a Comparative Analysis

Helicobacter pylori is a causative agent of gastritis, gastroduodenal ulcers and gastric adenocarcinoma. The majority of H. pylori-associated patients live in underdeveloped areas, facing the problem of lack of proper diagnostic facility. Hence, a simple and economical assay is required to handle the majority of gastric patients. Serum samples from gastroduodenal ulcers and gastritis patients were screened for H. pylori infection by thin layer immunoassay. A polystyrene plate coated with H. pylori sonicate whole cell antigen (10 µg/mL). Two-fold diluted patient's serum was allowed to react at 37 °C, incubated at 60 °C for 1 min over a water bath and the water condensation pattern for the H. pylori antibody was recorded. ELISAs were used as reference assays to evaluate the efficacy of the developed thin layer immunoassay (TLI). Gastric patients' blood samples (62% male and 6% female) tested positive for H. pylori, while age-wise, 15-25-year-old males (36%) and 65-75-year-old females (50%) showed the highest number of H. pylori infections. TLI showed sensitivity (72-67%), specificity (100%), accuracy (94-69%) and κ value (0.493-0.357) in comparison with wELISA (Surface whole cell ELISA), sELISA (sonicate whole cell ELISA) and kELISA (commercial KIT ELISA). We conclude that thin layer immunoassay is a low cost, fast, simple and clinically reliable method for H. pylori diagnosis at initial stages in patients in under-developed countries.

Mechanisms for the sex-specific effect of H. pylori on risk of gastroesophageal reflux disease and Barrett's oesophagus

BACKGROUND

Mechanisms for how Helicobacter pylori infection affects risk of gastroesophageal reflux disease (GERD) and Barrett's oesophagus (BE) are incompletely understood and might differ by sex.

METHODS

In a case-control study nested in the Melbourne Collaborative Cohort Study with 425 GERD cases and 169 BE cases (identified at 2007-10 follow-up), we estimated sex-specific odds ratios for participants who were H. pylori seronegative versus seropositive at baseline (1990-94). To explore possible mechanisms, we 1) compared patterns of H. pylori-induced gastritis by sex using serum pepsinogen-I and gastrin-17 data and 2) quantified the effect of H. pylori seronegativity on BE mediated by GERD using causal mediation analysis.

RESULTS

For men, H. pylori seronegativity was associated with 1.69-fold (CI:1.03-2.75) and 2.28-fold (CI:1.27-4.12) higher odds of GERD and BE, respectively. No association was observed for women. H. pylori-induced atrophic antral gastritis was more common in men (68%) than in women (56%; p=0.015). For men, 5 of the 15 per 1,000 excess BE risk from being seronegative was mediated by GERD.

CONCLUSIONS

Men, but not women, who were H. pylori seronegative had increased risks of GERD and BE. A possible explanation might be sex-differences in patterns of H. pylori-induced atrophic antral gastritis, which could lead to less erosive reflux for men. Evidence of GERD mediating the effect of H. pylori on BE risk among men supports this proposed mechanism.

IMPACT

The findings highlight the importance of investigating sex differences in the effect of H. pylori on risk of GERD and BE in future studies.

Hepatocyte Growth Factor in Blood and Gastric Cancer Risk: A Nested Case-Control Study

BACKGROUND

Potential of hepatocyte growth factor (HGF)-stimulating signaling pathways related to cytotoxin-associated gene A (CagA) to predict gastric cancer development has not been fully investigated.

METHODS

We conducted a nested case-control study consisting of 238 gastric cancer cases and 238 matched controls within the Korean Multicenter Cancer Cohort. Plasma HGF concentrations were measured with a human HGF ELISA. Odds ratios (OR) and 95% confidence intervals (CI) for gastric cancer development according to HGF level were calculated using conditional logistic regression model.

RESULTS

Sequential elevation of gastric cancer risk according to HGF level increase was observed (OR, 10.99; 95% CI, 4.91-24.62) for highest quartile HGF (≥364 pg/mL) versus lowest quartile HGF (<167 pg/mL). A significantly increased gastric cancer risk associated with high HGF level measured even 6 or more years prior to cancer diagnosis was also found. The group with both high risk of HGF and CagA-related genetic variants was associated with highest gastric cancer risk compared with the group with both low risk of HGF and genetic variants (P _interaction = 0.05). Model performance using HGF and CagA-related genetic variants to discriminate gastric cancer was fair [area under the curve of receiver operating characteristic (AUC-ROC), 0.71; 95% CI, 0.64-0.78] and significantly higher than that of model not including those biomarkers.

CONCLUSIONS

Our results suggest HGF as a potential biomarker to predict gastric cancer development.

IMPACT

These findings suggest HGF as a useful biomarker to predict gastric cancer risk. Further research to assess gastric cancer risk based on useful biomarkers, including HGF, may contribute to primary prevention of gastric cancer.

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 the serum and salivary antibodies to detect gastric Helicobacter pylori infection in Kashan (Iran)

Background and aim

Helicobacter pylori (H. pylori) is an important and common contagious human pathogen which may cause peptic ulcer and also gastric cancer. The definite diagnosis of it is made through invasive tests. Recently, non-invasive tests including serologic tests of serum and saliva have been conducted for diagnosis of H. pylori infection. In this research, the diagnostic values of serum and salivary serology were compared together to use salivary anti-H. pylori test as an alternative method in the future.

Methods

During this prospective case-control study on patients who were candidates for endoscopy and gastric biopsy from March 2015 to April 2016 in Shahid Beheshti hospital, Kashan, Iran, serum and salivary samples were obtained for measurement of Immunoglobulin G (IgG) antibody levels against H. pylori by enzyme-linked immunosorbent assay (ELISA). Histopathology was the gold standard test. Statistical analysis was performed by SPSS software version 16. Statistical tests included Kolmogorov-Smirnov, independent-samples t-test, Chi-square, Mann-Whitney U, Kruskal-Wallis, McNemar and correlation.

Results

Of 123 patients, sixty-one patients (49.6%) were H. pylori-positive according to histology. The median levels of anti-H. pylori antibodies in serum (p<0.001) and saliva (p<0.001) of H. pylori-positive cases were significantly higher than H. pylori-negative cases. Sensitivity, specificity, positive likelihood ratio, negative likelihood ratio and accuracy of serologic tests in serum were 75%, 79%, 3.5, 0.3, 77% and for saliva were 85%, 82%, 4.7, 0.18, 84% respectively.

Conclusion

Diagnostic values of salivary ELISA are comparable to serum ELISA and can be used as an alternative modality for diagnosis of H. pylori infection.

Correlation Between Expression of the Cancer/Testis Antigen KK-LC-1 and Helicobacter pylori Infection in Gastric Cancer

BACKGROUND/AIM

Our previous study indicated that Kita-kyushu lung cancer antigen-1 (KK-LC-1) is a cancer/testis antigen (CTA) expressed in 82% of gastric cancer cases. Here, we investigated the relationship between KK-LC-1 expression and Helicobacter pylori infection in Japanese patients with gastric cancer.

PATIENTS AND METHODS

We examined CTA expression in 25 surgical gastric cancer specimens and anti-H. pylori IgGs in the serum of each patient.

RESULTS

KK-LC-1 was expressed in 80% of tumor samples, markedly higher than melanoma antigen gene (MAGE)-A1, MAGE-A3, MAGE-A4, synovial sarcoma, X breakpoint 4 (SSX4) and New York esophageal squamous cell carcinoma-1 (NY-ESO-1). Anti-H. pylori IgG titers from the KK-LC-1-positive patients were significantly higher (67.5±7.6) than those from KK-LC-1-negative patients (15.8±7.5, p<0.01) although there were no significant differences between patients positive and negative for MAGE-A1, -A3 and-A4, SSX4 and NY-ESO-1.

CONCLUSION

As far as we are aware, this is the first report of a correlation between a carcinogen and CTA expression in clinical samples. KK-LC-1 was frequently expressed in gastric cancer caused by H. pylori infection. The risk diagnosis for gastric cancer might be more accurate if KK-LC-1 expression status were also considered.

Comparative Evaluation of RUT, PCR and ELISA Tests for Detection of Infection with Cytotoxigenic H. pylori

PURPOSE

Helicobacter pylori is one of the most prevalent infectious agents in the world which causes a variety of gastrointestinal diseases including gastritis, peptic ulcer and gastric carcinoma. The objective of this study was to comparatively evaluate invasive (rapid urease test and polymerase chain reaction) and non-invasive (enzyme-linked immunosorbent assay) tests in diagnosis of infection with cytotoxigenic H. pylori.

METHODS

Biopsy specimens and sera were collected from 105 patients with gastric disorders. The presence of H. pylori infection in gastric biopsies was evaluated by RUT and PCR methods using chemotaxis signal transduction protein gene (CSTP), Urea C and HP-16srRNA primers. Serum samples were used for the ELISA test. Detection of infection with cag A-positive strains was performed by PCR and cag A-IgG ELISA kit.

RESULTS

Patients with at least two out of three positive results were regarded as infected. The sensitivity, specificity, predictive value and accuracy of the three different methods were evaluated. Of the 105 gastric biopsies, H. pylori were positive in 51 patients (48.57%). The best sensitivity (92.16%) belonged to RUT. The sensitivities of other tests including PCR and ELISA test were 88.24% and 90.20%, respectively. PCR showed the best specificity (94.44%), and the specificities of the other tests including RUT and ELISA test, were 90.74 % and 61.11%, respectively. Furthermore, results of PCR and cag A-IgG ELISA showed high prevalence of cag A-positive strain in the study population.

CONCLUSION

Based on our findings, serum ELISA is a rapid noninvasive test for screening of H. pylori infection in the absence of endoscopy indication. In addition, considering the high prevalence of cytotoxigenic H. pylori strains, cag A is suggested as a promising target for PCR and non- invasive ELISA tests for detection of infection with toxigenic strains.

Diagnosis of Helicobacter pylori: Changes towards the Future

Since the first evidence demonstrating the dramatically high incidence of H. pylori infection and the subsequent medical challenges it incurs, health management of H. pylori infection has been a high priority for health authorities worldwide. Despite a decreasing rate of infection in western countries, prevalence of H. pylori infection in developing and in some industrial countries is still very high. Whereas treatment and vaccination against H. pylori is a contemporary issue in medical communities, selective treatment and prior high-throughput screening of the subject population is a major concern of health organizations. So far, diagnostic tests are either elaborative and require relatively advanced medical care infrastructure or they do not fulfill the criteria recommended by the Maastricht IV/Florence consensus report. In this review, in light of recent scientific studies, we highlight current and possible future approaches for the diagnosis of H. pylori. We point out that novel non-invasive tests may not only cover the requirements of gold standard methods in H. pylori detection but also offer the potential for risk stratification of infection in a high throughput manner.

Non-Invasive Diagnosis of Helicobacter pylori: Evaluation of Two Enzyme Immunoassays, Testing Serum IgG and IgA Response in the Anand District of Central Gujarat,India

CONTEXT

Validation of an accurate and less cumbersome noninvasive method to detect current Helicobacter pylori infection is a requisite for any laboratory.

OBJECTIVES

The purpose of this study is to corroborate the usefulness of two commercially available kits NovaTec ELISA-A and ELISA-G, in the detection of ongoing H.pylori infection.

MATERIALS AND METHODS

Two hundred and twenty eight consecutive serum samples of symptomatic patients who attended the endoscopy unit of "Deep" surgical hospital, Anand, which were collected during the period from 27th February 2008 to 31st august 2011, were studied. The sera were processed and tested for the detection of the H.pylori IgG and IgA antibody by using a solid phase; capture micro well ELISA, procured from Nova Tec immunodiagnostica GmbH Germany.

RESULTS

IgG ELISA showed 100% sensitivity and Negative predictive value (NPV), while IgA ELISA was better in terms of specificity (61.4%) and accuracy (63%) as compared to IgG ELISA. We found 7% (16/228) of IgA positive cases with IgG negative response. IgG response was more common in reflux esophagitis patients (OR 1.451, 95%CI-0.850-2.477) and then in gastritis (OR 0.962, 95%CI-0.570-1.621) and duodenitis(OR-0.806, 95%CI-0.112-5.827), while IgA positive response was more common in duodenitis patients (OR-1.383, 95%CI-0.191-9.995) and reflux esophagitis patients (OR 1.289, 95% CI-0.756-2.197) and least in duodenal ulcer patients (OR 0.670, 95%CI-0.222-2.029).

CONCLUSION

IgG update is reliable and accurate test and can be expedient as a screening test and thus serve as an alternative to endoscopy. For the purpose of excluding infection with H.pylori, the performance of IgG is moderate (low specificity) but can be improved by conjunctional IgA testing which will offer some additional diagnostic value.

A novel line immunoassay based on recombinant virulence factors enables highly specific and sensitive serologic diagnosis of Helicobacter pylori infection

Helicobacter pylori colonizes half of the world's population, and infection can lead to ulcers, gastric cancer, and mucosa-associated lymphoid tissue (MALT) lymphoma. Serology is the only test applicable for large-scale, population-based screening, but current tests are hampered by a lack of sensitivity and/or specificity. Also, no serologic test allows the differentiation of type I and type II strains, which is important for predicting the clinical outcome. H. pylori virulence factors have been associated with disease, but direct assessment of virulence factors requires invasive methods to obtain gastric biopsy specimens. Our work aimed at the development of a highly sensitive and specific, noninvasive serologic test to detect immune responses to important H. pylori virulence factors. This line immunoassay system (recomLine) is based on recombinant proteins. For this assay, six highly immunogenic virulence factors (CagA, VacA, GroEL, gGT, HcpC, and UreA) were expressed in Escherichia coli, purified, and immobilized to nitrocellulose membranes to detect serological immune responses in patient's sera. For the validation of the line assay, a cohort of 500 patients was screened, of which 290 (58.0%) were H. pylori negative and 210 (42.0%) were positive by histology. The assay showed sensitivity and specificity of 97.6% and 96.2%, respectively, compared to histology. In direct comparison to lysate blotting and enzyme-linked immunosorbent assay (ELISA), the recomLine assay had increased discriminatory power. For the assessment of individual risk for gastrointestinal disease, the test must be validated in a larger and defined patient cohort. Taking the data together, the recomLine assay provides a valuable tool for the diagnosis of H. pylori infection.

Development of an in-house enzyme-linked immunosorbent assay based on surface whole cell antigen for diagnosis of Helicobacter pylori infection in patients with gastroduodenal ulcer disease

Helicobacter pylori (H. pylori) is a causative agent of gastritis, gastroduodenal ulcers and gastric adenocarcinoma. More than 50% world population is colonized by H. pylori, which is closely related to the chronic gastritis and gastric ulcer infection. In this study, a total of 214 gastritis patient's serum samples were screened for anti-H. pylori IgG antibody. A 96-well plate coated with 20 μg/ml antigen and hundred-fold diluted patient's serum was allowed to react. After extensive washing with buffer, 1:2,500 diluted conjugated secondary antibody was added. Later substrate was added to observe positivity by measuring the intensity of color. Statistical analyses were performed, and p value of <0.01 was taken as significant; 84% male patients and 89% female patients, respectively, tested positive for H. pylori, while agewise distribution was 35-45 years males (40%) and 35-55 years females (52%) were found highest number of H. pylori infected patients. In-house ELISA based on surface whole cell antigen (wELISA) showed a sensitivity of 93%, specificity of 100%, accuracy 94% and κ value 0.86 with significant correlation R-0.77020; p < 0.0001. We conclude that H. pylori local isolates surface antigen was satisfactory for diagnosis as different parameters were adjusted according to the local H. pylori isolates. Fluctuations in serum antibody titer predict the variation in an individual's response of the host against H. pylori. In-house wELISA could provide a reliable and a clinically useful method for the diagnosis of H. pylori infection in patients of Karachi, Pakistan.

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.

Correlation of serology with morphological changes in gastric biopsy in Helicobacter pylori infection and evaluation of immunohistochemistry for H. pylori identification

BACKGROUND/AIM

Helicobacter pylori is implicated in various gastroduodenal diseases and many tests are available for its detection. The present study attempted to document the morphological changes in the gastric mucosa induced by H. pylori colonization and correlate them with the severity of the infection. The study also compared various diagnostic tests and evaluated the different staining methods used for H. pylori detection, especially immunohistochemical identification.

PATIENTS AND METHODS

One hundred and two patients with dyspepsia were included. Enzyme-linked immunosorbent assay (ELISA) for H. pylori-specific immunoglobulin G (IgG), immunoglobulin A (IgA), and immunoglobulin M (IgM) was used. Rapid urease test was performed on endoscopic biopsy and it was stained with hematoxylin and eosin (H and E), modified Giemsa, and immunohistochemical stains.

RESULTS

A significant correlation was found between the density of H. pylori and severity of gastritis. A significant correlation was observed between serology (especially when used in combination, IgG and IgA) and status of H. pylori. Immunohistochemical staining enhanced the diagnostic yield of H. pylori detection.

CONCLUSIONS

Immunohistochemistry (IHC) should be used judiciously, whereas simple and economical tests like modified Giemsa should be used routinely for the detection of H. pylori. Combined ELISA (IgG and IgA) should be preferred over single ELISA. Simultaneous morphological and serological detection of H. pylori is preferable as H. pylori may not be detected on morphology alone due to its patchy distribution in the stomach.

Factors contributing to the underestimation of Helicobacter pylori-associated gastric cancer risk in a high-prevalence population

OBJECTIVE

This study aimed to identify sources of underestimation of the association between Helicobacter pylori infection and non-cardia gastric cancer, in a high-risk European population.

METHODS

Non-cardia gastric cancer patients (n = 420) recruited in two major hospitals in North of Portugal and population controls (n = 1,389) were evaluated. Whole-cell IgG antibodies against H. pylori were quantified by ELISA and Western Blot testing was conducted in a subsample (272 cases and 186 controls) allowing for the detection of current infection marker and CagA. Sex- and age-adjusted odds ratios (OR) and 95% confidence intervals (95% CI) were computed.

RESULTS

When assessing infection by ELISA, the OR for its association with gastric cancer decreases and reverts as IgG titers increased, from 1.96 (95% CI: 1.09-3.54) for borderline positive results (16.0-21.9 RU/ml) to 0.52 (95% CI: 0.36-0.74) for the highest IgG levels (> or = 102.0 RU/ml). The same pattern was observed across strata of age and blood collection timing with stronger associations among younger subjects and those providing blood samples earlier after diagnosis. The presence of CagA (Western Blot) was associated with an increased risk of gastric cancer (OR = 11.32; 95% CI: 5.64-22.73).

CONCLUSION

The use of methods with low sensitivity to detect past infection leads to a substantial underestimation of gastric cancer risk in high-prevalence settings.

Antibody-based detection tests for the diagnosis of Helicobacter pylori infection in children: a meta-analysis

Background

Numerous serologic tests are available for the diagnosis of H. pylori infection in children. Common designs of antibody-based detection tests are ELISA and Western Blot (WB). For developing countries with limited laboratory resources and access, ELISA would be the preferred method because of its simplicity, lower cost and speed. Although in adults ELISA has proven to be highly accurate in diagnosing H. pylori infection; in children, it has shown variable accuracy.

Methods/Findings

We conducted a systematic review and meta-analysis to assess the accuracy of antibody-based detection tests for the diagnosis of H. pylori infection in children. Selection criteria included participation of at least 30 children and the use of a gold standard for H. pylori diagnosis. In a comprehensive search we identified 68 studies. Subgroup analyses were carried out by technique, immunoglobulin class, and source of test (commercial and in-house). The results demonstrated: 1) WB tests showed high overall performance, sensitivity 91.3% (95% CI, 88.9–93.3), specificity 89% (95% CI, 85.7–91.9), LR+ 8.2 (95% CI, 5.1–13.3), LR− 0.06 (95% CI, 0.02–0.16), DOR 158.8 (95% CI, 57.8–435.8); 2) ELISA-IgG assays showed low sensitivity 79.2% (95% CI, 77.3–81.0) and high specificity (92.4%, 95% CI, 91.6–93.3); 3) ELISA commercial tests varied widely in performance (test for heterogeneity p<0.0001); and 4) In-house ELISA with whole-cell antigen tests showed the highest overall performance: sensitivity 94% (95% CI, 90.2–96.7), specificity 96.4% (95% CI, 94.2–97.9), LR+ 19.9 (95% CI, 7.9–49.8), LR− 0.08 (95% CI, 0.04–0.15) DOR 292.8 (95% CI, 101.8–841.7).

Conclusions/Significance

WB test and in-house ELISA with whole-cell antigen tests are the most reliable tests for the diagnosis of H. pylori infection in children. Antigens obtained from local strains of the community could partially explain the good overall accuracy of the in-house ELISA. Because of its cost and technical demands, in-house ELISA might be more suitable for use in developing countries.

Diagnosis of Helicobacter pylori

The different invasive and noninvasive diagnostic tests for Helicobacter pylori have been applied mainly in emerging countries. Molecular methods have been developed, especially a test for detection of H. pylori and its clarithromycin resistance directly from stools. The long-term effects of eradication on histologic lesions have been studied in a meta-analysis and the prognostic value of post-treatment in gastric mucosa-associated lymphoid tissue lymphoma has been assessed. An operating link for gastritis assessment (the OLGA staging) has also been published. Attempts to simplify the urea breath test protocol have been made, and new stool antigen tests have been proposed and compared to those previously available.