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

OBJECTIVE: Although the diagnostic utility of serum IgG antibodies to Helicobacter pylori (H. pylori) is well established, the usefulness of IgA-based tests is less well documented. The aim of this study was to evaluate two commercially available ELISAs, both for IgG and IgA. PATIENTS AND METHODS: Rapid urease test and histology analysis were performed in 183 patients. A patient was considered to be H. pylori-positive when either biopsy test was positive, and considered to be noninfected when both tests were negative. Intestinal metaplasia was determined by dye endoscopy with methylene blue. ELISA testing was performed using the EPI HM-CAP IgG and PP-CAP IgA assays and EIAgen IgG and IgA assays. RESULTS: Sensitivity was 94.7, 93.9, 94.8, and 97.0% for HM-CAP IgG, PP-CAP IgA, EIAgen IgG, and EIAgen IgA, respectively. Although sensitivity was excellent for both IgG and IgA antibodies, specificity of both IgA EIAs was low (PP-CAP 72.6%, EIAgen H. pylori IgA 59.2%). Three of 101 H. pylori-infected patients were PP-CAP positive and HM-CAP negative and four were EIAgen H. pylori IgA positive and EIAgen IgG negative. Of eight noninfected patients in whom intestinal metaplasia was found, PP-CAP IgA results were positive in three of five patients with a HM-CAP IgG negative result and EIAgen IgA was detected in one of four patients with an EIAgen IgG negative result. CONCLUSIONS: Since some patients have IgA positive but IgG negative results, great care should be taken not to underestimate the prevalence of H. pylori infection from the results of IgG serology.     

Comparison of two enzyme immunoassays for the assessment of Helicobacter pylori status in stool specimens after eradication therapy

OBJECTIVES: Assessment of Helicobacter pylori antigen in stool specimens has recently been proposed as a valid method for the noninvasive detection of H. pylori infection, especially as posttreatment control. After the development of an enzyme immunoassay based on polyclonal antibodies (Premier Platinum HpSA) a monoclonally based test has recently been developed (FemtoLab H. pylori). The aim of the present study was to assess the diagnostic accuracy of both tests in adult patients undergoing H. pylori eradication therapy. METHODS: Stool samples were collected and the 13C-urea breath test performed in 148 patients (79 females and 69 males aged 21-75 yr) 4-6 wk after eradication therapy. The FemtoLab H. pylori and Premier Platinum HpSA tests were performed in accordance with the manufacturers' protocols. A receiver operator characteristics analysis was performed to define the optimal cutoff value on the basis of the results of the 13C-urea breath test. RESULTS: H. pylori eradication was successful in 113 of the 148 patients (76%). After adjusting the cutoff, the sensitivity of FemtoLab H. pylori was found to be higher than that of the Premier Platinum HpSA (94.3% vs 80.0%, ns). Specificity, positive predictive value, and negative predictive value of the two tests were comparable (93.8% vs 95.6%, 82.8% vs 85.2%, and 98.1% vs 93.8%, respectively). CONCLUSIONS: The new stool antigen test (FemtoLab H. pylori) is an excellent tool for diagnosing H. pylori infection after eradication therapy, and its accuracy is comparable with that of the Premier Platinum HpSA. Adjustment of the cutoff after H. pylori eradication therapy increases the overall accuracy.     

A novel enzyme immunoassay for serodiagnosis of Helicobacter pylori infection

Helicobacter pylori has recently been implicated as an etiologic agent of gastroduodenal disorders. Comparing the antibody to H. pylori in the sera of patients with that of normal controls by Western blot analysis, a unique antibody was detected in the sera of patients, which reacted with the 25-kilodalton antigen of H. pylori. On the other hand, monoclonal antibody CP3 prepared in the authors' laboratory also recognized the 25-kilodalton antigen of H. pylori. Whether the serum antibody of the patient recognized the CP3 antigen purified by monoclonal antibody CP3 was then examined. Western blot analysis showed that the patient's serum reacted strongly with the affinity-purified CP3 antigen. Using monoclonal antibody CP3, an enzyme-linked immunosorbent assay to detect CP3 antibody in sera was established. In patients with chronic gastritis and gastric ulcers, the titer of CP3 antibody was significantly higher than in normal controls and correlated with the histological grade of antral gastritis. The detection of CP3 antibody in sera is useful in the diagnosis of chronic gastritis and gastric ulcer associated with H. pylori infection and also in evaluation of the grade of gastritis.     

Current standards in the diagnosis of Helicobacter pylori infection

A large number of diagnostic tests are available for the diagnosis of Helicobacter pylori infection. These diagnostic methods include invasive and noninvasive methods. Culture yields the highest specificity and moreover allows the determination of strain resistance against antibiotics. Histology besides detection of H. pylori allows to assess morphological changes of the gastric mucosa. In clinical practice, the rapid urease test is very convenient and highly accurate. The (13)C-urea breath test and the recently developed stool antigen test are reliable noninvasive tests with a high diagnostic accuracy in pre- and posttreatment conditions. Serological tests have a lower diagnostic accuracy and should only be used for screening of H. pylori infection or after careful local validation.     

Evaluation of rapid antibody tests for the diagnosis of Helicobacter pylori infection

OBJECTIVE: The aim of this study was to compare the performance characteristics of one serum and four whole blood rapid antibody tests for Helicobacter pylori infection. METHODS: A total of 97 outpatients referred for endoscopic evaluation of dyspepsia were included. Antral biopsies were obtained for histology and rapid urease test. Serum was tested with an enzyme-linked immunoassay (HM-CAP) and a rapid serology test (FlexSure HP). A commercially available 13C-urea breath test was performed. Capillary blood obtained by fingerstick was tested with FlexSure HP, QuickVue, Accustat, and StatSimple pylori tests. Sensitivity, specificity, and accuracy of each rapid test was calculated relative to a criterion standard of histological gastritis and at least two of the four following tests positive: identifiable organisms on specially stained slides, rapid urease test, urea breath test, or serum immunoassay. RESULTS: A total of 30 patients (31%) were infected. The FlexSure HP Serum, and FlexSure HP, QuickVue, Accustat, and StatSimple pylori whole blood tests had sensitivities of 90%, 87%, 83%, 76%, and 90%; specificities of 94%, 90%, 96%, 96%, and 98%, and accuracies of 93%, 88%, 92%, 87%, and 96%, respectively. Sensitivities were not statistically different. StatSimple pylori was more specific than FlexSure HP whole blood (p<0.03), and more accurate than FlexSure whole blood (p<0.024) and Accustat (p< 0.01). Serum immunoassay was significantly more sensitive (97%) than FlexSure whole blood, QuickVue, and Accustat (p<0.01), but its specificity (95%) was not statistically different from the rapid tests. CONCLUSION: Rapid antibody testing provides an accurate diagnosis of H. pylori infection. In general, these tests are less sensitive than, but as specific as, standard serology.     

Helicobacter pylori infection - recent developments in diagnosis

Considering the recommended indications for Helicobacter pylori (H. pylori) eradication therapy and the broad spectrum of available diagnostic methods, a reliable diagnosis is mandatory both before and after eradication therapy. Only highly accurate tests should be used in clinical practice, and the sensitivity and specificity of an adequate test should exceed 90%. The choice of tests should take into account clinical circumstances, the likelihood ratio of positive and negative tests, the cost-effectiveness of the testing strategy and the availability of the tests. This review concerns some of the most recent developments in diagnostic methods of H. pylori infection, namely the contribution of novel endoscopic evaluation methodologies for the diagnosis of H. pylori infection, such as magnifying endoscopy techniques and chromoendoscopy. In addition, the diagnostic contribution of histology and the urea breath test was explored recently in specific clinical settings and patient groups. Recent studies recommend enhancing the number of biopsy fragments for the rapid urease test. Bacterial culture from the gastric biopsy is the gold standard technique, and is recommended for antibiotic susceptibility test. Serology is used for initial screening and the stool antigen test is particularly used when the urea breath test is not available, while molecular methods have gained attention mostly for detecting antibiotic resistance.     

Accuracy of the Ultra-Rapid Urease Test for diagnosis of Helicobacter pylori infection

Background

Rapid Urease Test (RUT) is a simple, cheap and relatively fast method for diagnosing Helicobacter pylori infection. It is therefore the preferred method used for patients undergoing gastroscopy. Most kits require 24 h to give results. The new Ultra-Rapid Urease Test (URUT) kit by Biohit® requires less than 1 h.

Capsule 13C-urea breath test for the diagnosis of Helicobacter pylori infection

AIM: To compare the accuracy of capsule 13C-urea breath test (UBT) with conventional invasive methods for the diagnosis of Helicobacter pylori infection. METHODS: One hundred patients received CLO test, histological examination, culture and 100- or 50-mg capsule UBT for the diagnosis of H pylori infection. H pylori infection was defined as those with positive culture or positive results from both histology and CLO test. RESULTS: Both the sensitivity and specificity of the 100-mg capsule UBT (n=50) were 100%. The sensitivity and specificity of the 50-mg capsule UBT (n = 50) were 96.4 and 100%, respectively. Taken together, the accuracy of capsule UBT (n =100) was higher than that of CLO test, histology and culture (100% vs 92%, 91% and 89%, respectively; P= 0.035, 0.018 and 0.005, respectively). Our data showed that the optimal timing of sampling for 100-and 50-mg capsule UBT was 15-30 and 6-15 min, respectively. CONCLUSION: Capsule UBT has a higher accuracy compared with biopsy-based tests. It is an ideal method for the diagnosis of H pylori infection.     

Association of Helicobacter pylori infection with elevated serum lipids

Helicobacter pylori causes a chronic gastric infection, which has been associated with coronary heart disease. To evaluate the mechanisms of this association, we studied whether the infection affects serum lipid levels as previously shown in acute infections. We analysed the serum samples of 880 males who participated in a reindeer herders’ health survey in Northern Finland in 1989. H. pylori IgG and IgA antibodies were measured by enzyme-linked immunosorbent assay and triglyceride, total cholesterol and high-density lipoprotein cholesterol concentrations by routine enzymatic methods. A total of 52% of the subjects were positive for both H. pylori specific IgG and IgA and 31% were antibody-negative. The serum triglyceride and total cholesterol concentrations were significantly higher in the males with positive IgG and IgA antibody titres for H. pylori than in the males with no signs of infection (1.20 vs. 1.03 mmol/l, P<0.001 and 6.59 vs. 6.11 mmol/l, P<0.001, respectively). The associations remained statistically significant in non-smokers after the adjustment for age, body mass index (BMI) and social class. The finding supports the hypothesis that chronic infections may modify the serum lipid profile in a way that increases the risk of atherosclerosis.     

Helicobacter pylori Stool Antigen test: a reliable non-invasive test for the diagnosis of Helicobacter pylori infection in children

OBJECTIVE: To evaluate the Helicobacter pylori Stool Antigen (HpSA) test for the diagnosis of H. pylori infection in children. DESIGN AND SETTING: Prospective cohort study in an academic medical centre. PATIENTS AND METHODS: A total of 106 consecutive children who underwent gastroscopy were included. Biopsy specimens were sampled from the gastric antrum and corpus for the assessment of H. pylori infection by culture and histology. A patient was defined to be H. pylori positive if the results of culture and/or histology proved to be H. pylori positive; a patient was defined to be negative if both test results were negative. All children provided a stool sample within 2 days of gastroscopy. H. pylori antigens in faeces were assessed by an enzyme immunoassay (Premier HpSA, Meridian Diagnostics, Inc., Cincinnati, OH, USA). RESULTS: The mean age of included patients was 8.5 years (range 1-18.5). Thirty patients were H. pylori positive and 76 patients were H. pylori negative. Using the recommended cut-off values of 0.140 optical density (OD) and 0.159 OD, sensitivity and specificity of 100% and 92% were found. The positive and negative predicting values were 83% (30/36) and 100% (70/70), respectively. CONCLUSION: The HpSA test is an accurate test for the diagnosis of H. pylori infection in children, and might therefore be a good alternative for diagnostic tests such as the 13C-urea breath test (UBT).     

Use of the 'Polymerase Chain Reaction' for the diagnosis of Helicobacter pylori infection

PURPOSE: H. pylori infection can be diagnosed by means of non-invasive tests or invasive techniques using endoscopy. The choice of the test depends on available instruments, type of diseases, aim of diagnostic research (therapeutic or epidemiological) and test features. PCR is able to reveal pathogenic germs in biological material with very high sensitivity and specificity. In vitro DNA amplification method consists of hybriding denaturated DNA by means of two oligonucleotide primers that allow to copy DNA fragment. The aim of our study was to determine, using PER, H. pylori colonization in the gastric mucosa of 18 consecutive patients under-went gastroscopy. MATERIALS AND METHODS: Eighteen patients complaining of dyspeptic symptoms and referred to us for upper GI endoscopy participated in the study. The studied population comprised 9 males and 9 females with mean age of 55.4 yrs (range 26-73 years). All patients underwent gastroscopy during which 4 biopsies from the antrum and 4 from the corpus were obtained for Giemsa stain, PCR analysis and histologic examination. A pair of synthetic oligonucleotides for H. pylori urease A gene, designated as HPU1 and HPU2, were used. Urease A gene fragment amplified by PCR was analyzed by 1.5 agarose gel electrophoresis. Positivity for H. pylory corresponded to PCR DNA products migrating at 411 bp after staining with ethidium bromide. RESULTS: The patients were divided into two groups, according to H. pylori infection, determined by means of Giemsa stain: group A, comprising 11 H. pylori-positive patients; and group B, with 7 H. pylori-negative patients. Our PCR assay of gastric mucosa samples proved positive in 7 cases of group A (63.6%), whereas it always proved negative among group B subjects (100%). CONCLUSIONS: Our findings, apparently in contrast with the high sensitivity of PCR, may be attributed to the lower specificity of histology or, alternatively, the absence of H. pylori in the samples tested by PCR due to the patchy distribution of H. pylori colonization in the gastric mucosa. These observations are in agreement with those from other investigations.     

幽门螺杆菌感染内镜下的诊疗方法

目的探讨活检部位与Ｈｐ的检出率，观察内镜下喷洒美蓝治疗Ｈｐ的效果．方法选择内镜下诊断的慢性萎缩性胃炎或其它胃病伴有萎缩改变及肠上皮化生改变者２６８例．对其萎缩面的形态、肠上皮化生的特点进行分型．结果闭合型萎缩性胃炎以窦部Ｈｐ检出率高，而开放型以体部检出率高（Ｐ＜００１），肠上皮化生广泛的部位，Ｈｐ检出率低（Ｐ＜００１）．美蓝喷洒法与口服法比较具有相同治疗效果．结论内镜下取活检的部位及肠上皮化生的程度可影响Ｈｐ检出率．喷洒美蓝治疗Ｈｐ法，经济、效果好、副作用少．     

Helicobacter pylori infection

Summary The present report describes two patients with fasting hypergastrinemia, gastric acid hypersecretion, andHelicobacter pylori gastritis. Provocative testing for Zollinger-Ellison syndrome was negative and imaging studies did not demonstrate an intra-abdominal mass. Following eradication of theHelicobacter pylori infection, the fasting hypergastrinemia resolved in both patients and in one patient the gastric acid hypersecretion also resolved. The implications of this case on the differential diagnosis of Zollinger-Ellison syndrome are discussed.     

Helicobacter pylori infection in subjects negative for high titer serum antibody

AIM To investigate the clinicopathological features of the patients testing negative for high titer serum antiHelicobacter pylori(H. pylori) antibody.METHODS The antibody titers were measured using antigens derived from Japanese individuals. ~(13)C-urea breath test-positive individuals were defined as having H. pylori infection. We investigated the demographic characteristics, laboratory data, endoscopic findings including Kyoto classification of gastritis, and histology in negative-high titer patients without H. pylori eradication therapy. Kyoto classification consisted of scores for gastric atrophy, intestinal metaplasia, enlarged folds, nodularity, and redness.RESULTS Of the 136 subjects enrolled, 23(17%) had H. pylori infection. Kyoto classification had an excellent area under the receiver operating characteristics curve(0.886, 95% confidence interval: 0.803-0.968, P = 3.7 × 10~(-20)) for predicting H. pylori infection with a cutoff value of 2. Further, Kyoto classification, H. pylori density, and neutrophil activity had high accuracies(89.7%, 96.3%, and 94.1%, respectively). Kyoto classification was independent of the demographic and laboratory parameters in multivariate analysis.CONCLUSION Endoscopic Kyoto classification of gastritis is a useful predictor of H. pylori infection in negative-high titer antibody patients.     

Helicobacter pylori infection

IS THERE ANYTHING NEW? Helicobacter pylori has been for many years a forgotten bacterium, since the first report on this spiral organism dated from the 19th century[1]. As early as in 1906, an association between a spiral organism and gastric carcinoma was suggested[2].Doenges reported in 1938 that on autopsy not less than 40% of human stomachs were found to be invaded by spiral organisms[3].     

Usefulness of the Helicobacter pylori stool antigen test for detection Helicobacter pylori infection

Several diagnostic tests are available for evaluating Helicobacter pylori (H. pylori) infection: histological examination, culture of gastric biopsy specimens, rapid urease test, urea breath test and serology. In this study, we assessed the reliability of a newly developed enzyme immunoassay HpSA (H. pylori Stool Antigen) kit for detecting H. pylori antigen in stool. Eighty-five patients (50 males, 35 females; mean age 41.6 +/- 9.8 years) with dyspeptic symptoms who were examined by upper gastrointestinal endoscopy. The patients with a history of previous treatment with proton pump inhibitors, bismuth compounds or antibiotics were excluded. During the endoscopic examination biopsies were taken from antrum and corpus for rapid urease test and histological examination. Stool specimens were submitted to the laboratory and HpSA test was performed. H. pylori was considered in condition with rapid urease test and histopathological examination for H. pylori positive. Forty-six of 85 patients were positive and remaining 39 patients were negative for H. pylori with the rapid urease test and pathologic evaluation. When 0.160 was adopted as the cut-off value, in accordance with the manufacturer's recommendations; stool antigen has been detected in 45 of the 46 H. pylori positive patients. The sensitivity and specificity of HpSA test were 97.8%, 94.9% respectively. These results indicate that HpSA is a highly reliable diagnostic method for H. pylori infection.     

十二指肠癌及溃疡组织幽门螺杆菌感染对比

目的研究幽门螺杆菌(Helicobacter pylori,Hp)在十二指肠溃疡及十二指肠癌中的表达及意义。方法采用免疫组织化学染色方法检测40例十二指肠溃疡组织(对照组)和32例十二指肠癌组织(观察组)中Hp表达情况。结果对照组Hp阳性表达率(72.5%)与观察组(12.5%)差异显著(P<0.005)。结论 Hp感染在十二指肠溃疡发生发展中起着重要作用,而与十二指肠癌发生关系不大。