Salivary immunoglobulin G assay to diagnose Helicobacter pylori infection in children.

An in-house enzyme-linked immunosorbent assay (ELISA) for measurement of Helicobacter pylori-specific immunoglobulin G (IgG) and IgA in saliva was evaluated by comparison with histopathologic (Giemsa staining) and biochemical (urease quick test) examination of gastric biopsy specimens obtained from 112 children referred for diagnostic gastroscopy. Serum H. pylori IgG was also measured in a subgroup of 50 children by the same ELISA. Salivary H. pylori IgG levels were significantly higher in H. pylori-positive (n = 57) than in H. pylori-negative (n = 55) children (P < 0.001). The sensitivity and specificity of the salivary IgG test were 93 and 82%, respectively; the positive and negative predictive values were 84 and 92%, respectively; and the accuracy was 87.5%. Salivary H. pylori IgA did not distinguish H. pylori-positive from H. pylori-negative children. The performance of serum H. pylori IgG was slightly (3 to 6%) better than that of salivary H. pylori IgG. The salivary IgG test can be considered a useful tool for the screening of H. pylori infection in children.     

Evaluation of a Western blot technique (Helicoblot 2.1) for the diagnosis of Helicobacter pylori infection in children

AIM: We evaluated the performance of Helicoblot 2.1 which differentiates the reactivity to each of the various Helicobacter pylori antigens, and compared the results with those obtained by standard techniques (rapid urease test and histological examination of gastric biopsy) in symptomatic children of different ages living in Antalya, Turkey. METHODS: Eighty-eight children (mean age, 9.15 years) were divided into two groups. The first group included 66 children who were found to be infected with H. pylori. The second group included 22 children who were negative for H. pylori. Serum samples collected from all patients were tested for H. pylori IgG antibodies by immunoblot assay (Helicoblot 2.1). RESULTS: The sensitivity, specificity, positive and negative predictive values for detection of H. pylori infection were 80%, 100%, 100% and 85%, respectively. In children under 7 years of age, the sensitivity of the test was found to be lower than other age groups (P<0.05). No relationship was found between peptic ulcer and cagA antibody positivity (P>0.05). CONCLUSION: Helicoblot 2.1 is a useful non-invasive diagnostic tool for H. pylori infection in children over 6 years of age.     

Role of ELISA in H. pylori detection and its correlation with urease test

Helicobacter pylori is one of the most common chronic bacterial infection in humans linked to acid peptic diseases, gastric carcinomas and lymphomas. The bacilli produces large amounts of urease and this property has formed the basis of detection of H. pylori by the Christensen's urease test. Where endoscopy is not clinically indicated, serology may be used to establish the diagnosis. This study was undertaken to diagnose H. pylori with the help of Christensen's urease test on endoscopic biopsy specimens & correlated with the detection in Sera, of IgG antibodies against H. pylori, by ELISA technique. The study was conducted on 100 patients suffering from acid peptic disorders out of which 40 (40%) tested positive for H. pylori both by urease and serology. Christensen's urease and ELISA were found to have sensitivities of 85.7% & 90.9% and specificities of 96% and 87.5% respectively. Christensen's urease was taken as a standard method of diagnosis and its correlation with ELISA worked out to (+1) which meant there was a strong positive association between both the tests. Hence either test could be used for primary diagnosis of H. pylori instead of histopathological study and/or culture of H. pylori.     

Evaluation of a commercial ELISA for serodiagnosis of Helicobacter pylori infection.

A commercial ELISA for the detection of Helicobacter pylori IgG antibodies was evaluated using serum from 242 patients attending an endoscopy clinic. The efficacy of the ELISA was assessed in relation to the histological detection of H pylori on antral mucosal biopsy specimens. In patients under 61 years of age (n = 138) the ELISA was 97.5% sensitive and 85.5% specific for H pylori infection, with a positive predictive value of 91% and a negative predictive value of 96%. Over the whole group the sensitivity of the ELISA was 93.8% and the specificity 79.3%. The positive predictive value and negative predictive values were, respectively, 90% and 87%. These results suggest that the Bio-Rad GAP IgG H pylori ELISA is suitable for serodiagnosis of H pylori infections for most clinical purposes and thus makes H pylori serology available to routine diagnostic laboratories.     

Immune responses to Helicobacter pylori in children with recurrent abdominal pain.

The systemic immune response to Helicobacter pylori was examined in 69 children with recurrent abdominal pain and upper gastrointestinal symptoms. Twenty one (30%) children were histologically positive for H pylori. Eighteen of the 21 positive subjects and two H pylori negative subjects (one with normal mucosa, one with lymphocytic gastritis) were positive for H pylori IgG antibodies by enzyme linked immunosorbent assay (ELISA) (86% sensitivity, 98% specificity). In children with H pylori associated gastritis, there was a significant positive correlation (p less than 0.05) between IgG antibody titres and patient age. Intra-assay comparison of sera from histologically negative adults with those of histologically negative children showed that the cut off for positivity in the ELISA for adults was greater than that for children. Immunoblotting showed IgG positivity in 20 of the 21 patients with H pylori infection (95% sensitivity). Both ELISA and immunoblotting for IgA and IgM H pylori antibodies had poor discriminatory value for determining infection. Serological detection of H pylori IgG antibodies seems to be valuable in the assessment of children presenting with recurrent abdominal pain and other gastrointestinal symptoms, but assays must first be validated in paediatric populations.     

Serological detection of Helicobacter pylori antibodies in children and their parents.

The antibody response to Helicobacter pylori was examined in 56 children (ages 5 to 18) to determine whether serological tests can be used for diagnosis. Twenty-four children (43%) were H. pylori positive and 32 children (57%) were H. pylori negative by culture and histological examination of endoscopic biopsy specimens. The immune response was also examined in 39 nonendoscoped parents of the children. H. pylori-specific immunoglobulin G (IgG) and IgA antibodies were detected by the flow microsphere immunofluorescent assay (FMIA). IgG was also detected by using the Pyloristat enzyme-linked immunosorbent assay (ELISA). The sensitivity, specificity, and positive and negative predictive values for the FMIA for IgG were 100, 97, 96, and 100%, respectively. The respective values for the Pyloristat ELISA for IgG were 96, 94, 92, and 97%. The respective values for the FMIA for IgA were 50, 100, 100, and 73%. Both assays identified the same 19 parents as IgG positive, while FMIA identified 17 of the 19 parents as IgA positive.     

Non-invasive techniques for the diagnosis of Helicobacter pylori infection

Helicobacter pylori infection can be diagnosed by invasive techniques requiring endoscopy and biopsy (histologic examination, culture, polymerase chain reaction), and non-invasive techniques (serology, urea breath test, urine or blood, detection of H. pylori antigen in stool specimen). However, recent studies have demonstrated that a strategy of 'testing and treating' for H. pylori in uninvestigated, young (<50 years), dyspeptic patients in primary care is safe and reduces the need for endoscopy. Indeed, a number of clinical guidelines recommend non-invasive testing in dyspeptic patients followed by treatment of H. pylori in primary care based on clinical and economic analyses. Several non-invasive tests are currently available on the market. The choice depends on the clinical circumstances, the likelihood ratio of positive and negative tests, the cost-effectiveness of the testing strategy, and, finally, the availability of the tests. Nevertheless, two non-invasive tests are commonly used: the urea breath test, and the stool antigen test.     

Evaluation of infection by Helicobacter pylori in HIV positive patients trough enzyme immunoassay and specific amplification of DNA

The objective of this work was to assess the effectiveness of detection of specific antibodies anti-Helicobacter pylori (H. pylori) by ELISA and amplification of specific DNA by polimerase chain reaction (PCR) as diagnostic methods of infection of H. pylori in HIV positive patients. Twenty two patients with HIV infection were studied, with ages between 26 to 35 years, 17 masculine, 55% with gastrointestinal symptoms, controlled in the Unit of Immunology, CHET. Inclusion approaches: older than 18 years, with confirmed diagnosis of HIV infection (ELISA and WB), lymphocyte subpopulation and good general conditions. Consent in writing was obtained. Exclusion approaches: previous diagnosis of H. pylori infection or treatment with antibiotics in the three previous months to their inclusion. The quantification of IgG anti H. pylori was carried out by Enzyme Immunoassay methods (ELISA). Biopsy of gastric mucosa was obtained by superior endoscopic study. The amplification of DNA for H. pylori was performed by PCR (Wizard SV Genomik and PCR Ready-Promega). In the statistical analysis was used the test of Fisher, with a level of significance of 5% (0.05). In 15 patients of the total group, antibodies anti H. pylori were confirmed, without statistical association with the presence or not of digestives symptoms, neither with the number of lymphocytes CD4 + in peripheral blood. Also 15 patients were positives by PCR for H. pylori DNA, 73.3% of them presented levels of CD4+ above 200 cells. There was not statistical association between the positivity of this method and levels of lymphocytes CD4+. In 12 of the 15 patients with positive results by PCR, antibodies anti H. pylori were evidenced, and among the 7 patients with negative serology to H. pylori, PCR was positive in three of them. In conclusion, serology is an effective method for the diagnose of H. pylori infection in VIH+ patients, but its negativity doesn't discard the infection for this bacillus.     

Study of diagnostic modalities and pathology of Helicobacter pylori infection in children

To evaluate various diagnostic tests for Helicobacter pylori (Hp) in children, and to study the spectrum of endoscopic and histological changes in the stomach and duodenum of children with gastroduodenal disorders, associated with Hp infection Children below 12 years of age with various gastroduodenal disorders requiring upper gastrointestinal endoscopy were studied. Endoscopic biopsy specimens were collected from duodenum and antrum. Apart from histopathological examination of biopsy material, rapid urease test (RUT) of the antral biopsy specimen and blood examination to estimate specific IgG antibodies to Hp by Indirect Solid Phase Enzyme Immunoassay was performed. Forty seven children were included. Nine (19.1%) of them were positive both by serology and RUT. Seven (14.9%) were positive by histology. A significant correlation of Hp was noticed with chronic antral gastritis (p = 0.002) and chronic duodenitis (p = 0.006). Age equal to or more than 10 years was found to be significant risk factor for acquiring Hp infection. Prevalence of Hp in children with gastroduodenal complaints was found to be 19%. Both RUT and serology were found to be reliable diagnostic tests for Hp as compared with histology. Antral gastritis and chronic duodenitis had a significant correlation with Hp colonization.     

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.     

Evaluation of the performance of commercial test kits for detection of Helicobacter pylori antibodies in serum.

We have compared the sensitivities, specificities, and predictive values of three commercial serological assays for the diagnosis of Helicobacter pylori infection. A qualitative latex method (Pyloriset; Orion Diagnostics), a semiquantitative enzyme-linked immunosorbent assay (ELISA) (GAP test IgG; Bio-Rad), and a quantiative ELISA (Helico-G; Porton Cambridge) were used in 109 untreated dyspeptic patients. The presence of H. pylori was established when the results of culture and/or histology of the gastric biopsies taken were positive. The prevalence of H. pylori infection was 62% (52% in 42 patients younger than 45 years of age and 69% in 67 patients older than 45 years of age). Sensitivities and specificities were 68 and 76% for Pyloriset, 89 and 77% for GAP test IgG, and 82 and 83% for Helico-G. The positive predictive values for all three tests were between 85 and 90%. The predictive values for the absence of disease with a negative result were 62, 82, and 74% for Pyloriset, the GAP test, and Helico-G, respectively. With Helico-G in the younger group (less than 45 years), sensitivity significantly lower (71 versus 87%) and a positive predictive value lower than those for the older group (greater than 45 years) were found. Either the sensitivities and specificities of commercial methods for the measurement of antibodies to H. pylori in serum must be improved or the relationship between the presence of antibodies and the presence of bacteria in the stomach at the time of investigation is too weak to allow the use of serological techniques instead of culture and histological investigation of gastric biopsy material.     

Diagnosis of Helicobacter pylori infection in adults and children by using the Malakit Helicobacter pylori, a commercially available enzyme-linked immunosorbent assay.

Malakit Helicobacter pylori (Biolab, Limal, Belgium) is a second-generation enzyme-linked immunosorbent assay (ELISA) for the detection of Helicobacter pylori infection. We evaluated its ability to diagnose H. pylori infection in 489 asymptomatic pregnant women, 427 asymptomatic children, and 95 symptomatic children. 87 asymptomatic adults (17.8%), 31 asymptomatic children (7.3%), and 27 symptomatic children (28.4%) were seropositive. We observed an increase in H. pylori infection with age. 13C-urea breath tests were performed for all seropositive and 100 randomly selected seronegative asymptomatic adults. They were also performed for all seropositive and 65 randomly chosen seronegative asymptomatic children. Breath tests were positive for 86 of 87 (98.9%) seropositive adults, 30 of 31 seropositive children (96.8%), and no seronegative individual. Compared with those of culture, the sensitivity and specificity of the Malakit Helicobacter pylori were both 96%. We conclude that the Malakit Helicobacter pylori is equally suitable for adults and children. Therefore, this ELISA can be proposed as an important alternative to other more time-consuming and/or more expensive diagnostic tests for the detection of H. pylori.     

Isolation and preliminary evaluation of a low-molecular-mass antigen preparation for improved detection of Helicobacter pylori immunoglobulin G antibodies.

Previously, immunoglobulin G (IgG) antibodies to five antigens with a relative molecular mass of between 15 and 30 kDa from Helicobacter pylori were found to be significantly more frequent in H. pylori-infected patients than in noninfected patients. In this study, these specific low-molecular-mass (LMW) antigens were separated by ultrafiltration of whole-cell sonicates. The LMW antigen preparation was evaluated by enzyme-linked immunosorbent assay with serum samples from 76 children with abdominal symptoms and 151 adults with dyspeptic symptoms. H. pylori was cultured or seen in 40 (53%) children and 83 (55%) adults. Increased antibody levels to H. pylori were found in serum from 35 (46%) children and 88 (58%) adults. Values for sensitivity, specificity, and predictive value of positive and negative results of the test were higher with LMW antigens than with the heat-stable antigen previously described. The low specificity and predictive value of a positive result were due to seropositive results for 21 persons with a negative culture for H. pylori and negative microscopy results for Helicobacter-like organisms in biopsies from gastric mucosa. Histologically, chronic gastritis was demonstrated in 43% of these persons, and 19% had peptic ulcer, indicating that they have or have had H. pylori infection. Specific antibodies to H. pylori were confirmed in all 21 patients by the Western immunoblot technique. Use of the LMW antigen improved the IgG antibody detection in patients with H. pylori infection, even though the results reflect the difficulties in establishing a true gold standard for diagnosis of H. pylori infection.     

Effect of transport medium and transportation time on culture of Helicobacter pylori from gastric biopsy specimens.

To determine whether transportation time and use of a low budget transport medium (NaCl 0.9%) would influence culture of Helicobacter pylori from gastric biopsy specimens, upper gastrointestinal endoscopy was performed on 42 patients. The specimens were cultured and examined histologically, and H pylori antibodies were determined using an ELISA technique. Patients were regarded as H pylori positive when culture was positive or when histology or IgG anti-H pylori antibodies indicated H pylori infection. Rapid transportation of gastric biopsy specimens in NaCl 0.9%, at room temperature resulted in a high diagnostic yield (23 H pylori positive cultures in 26 patients with H pylori infection). A 24 hour delay in plating gastric biopsy specimens after transportation in NaCl 0.9%, at room temperature, did not seriously affect results (22 instead of 23 H pylori positive cultures). The culture results after transportation in Cairy-Blair medium were comparable with those after transportation in NaCl 0.9%, but because of availability, low cost, and ease of handling in the endoscopy department, NaCl 0.9% was preferred as transport medium. This study shows that for culture of H pylori from gastric biopsy specimens sterile saline is an adequate medium, and that transportation can be delayed for 24 hours without a significant loss of diagnostic yield.     

Detection of Helicobacter pylori infection in symptomatic Bulgarian adults

This study assessed the prevalence of Helicobacter pylori in symptomatic Bulgarian adults by means of culture, Gram's stain and an in-house rapid urease test (RUT), and also assessed the H. pylori density by culture. In total, 1441 non-treated and 270 treated patients were evaluated. Most non-treated patients with ulcers (87.7%), gastric malignancy (79.2%) and other gastroduodenal diseases (73.4%) were H. pylori-positive. Among non-treated and treated patients, 75.3% and 54.8%, respectively, of elderly patients, and 78.3% and 56.1%, respectively, of other adults were H. pylori-positive. Two (0.1%) non-treated adults were Helicobacter heilmannii-positive. The accuracy of direct Gram's stain and the in-house RUT were 74.8% and 64.2% in non-treated patients, and 73.7% and 63.0% in treated patients, respectively. Culture was highly accurate (>95%) in both groups. Older age decreased the sensitivity of the RUT in non-treated patients by 10.7% and that of all tests in treated patients by 6.9-8.1%. Incubation for 11 days was required for the growth of 2% and 4% of the strains from treated patients on selective and non-selective medium, respectively. There were no differences in isolation rates between positive fresh (74.2%) and frozen (75.2%) specimens. In non-treated adults, a high H. pylori density (growth in all quadrants of the plates) was more common (43.1%) in ulcer patients than in other patients (25.4%). In conclusion, H. pylori infection was common in Bulgarian patients, and at a high density in >40% of ulcer patients, while H. heilmannii infection was uncommon. Culture provided a highly accurate diagnostic approach. Stomach biopsies from non-treated patients can be frozen for several days. The benefit of reporting H. pylori density, as determined by culture, requires further evaluation.     

Estimation of prevalence of Helicobacter pylori infection in an asymptomatic elderly population comparing [14C] urea breath test and serology.

A non-invasive serological assay devised in this laboratory had a sensitivity and specificity of 100% as determined by culture and confirmed by histology in a group of 47 patients who had undergone endoscopy. The correlation between serology and the non-invasive [14C] breath test was very good. Only one of 24 culture positive patients was, while all 23 culture negative patients were, breath test negative. In a group of 46 healthy elderly persons, however, significant anomalies between serology and breath test were observed. Only 83% of the breath test negative persons were seronegative, while only 68% of the breath test positive persons were seropositive. These results can be explained in terms of age related atrophic gastritis and immune incompetence, causing reduced colonisation and decreased antibody production, respectively. These investigations suggest that non-invasive tests for H pylori infection may not be reliable in the elderly.     

Diagnosis of Helicobacter pylori infection by specific gastric mucosal IgA and IgG pylori antibodies.

AIMS--To investigate the diagnostic value of mucosal IgA and IgG Helicobacter pylori antibodies. METHODS--The study population comprised 209 consecutive patients with severe dyspeptic complaints referred for upper gastrointestinal endoscopy. A positive culture or histological identification of H pylori in gastric biopsy specimens, or both, were used to confirm infection. Specific IgA and IgG H pylori antibodies were determined using a modified ELISA technique. RESULTS--Of the 209 patients, 137 were infected with H pylori. The diagnostic value of systemic IgA and IgG H pylori antibodies was confirmed. Systemic IgA antibodies had a sensitivity of 76.6% (95% confidence interval 69.5-83.7) and a specificity of 94.4% (89.1-99.7). The sensitivity and specificity for systemic IgG antibodies were, respectively, 97.1% (94.3-99.9) and 98.6% (95.9-100). A moderate but clinically important correlation was found between local and systemic IgA and IgG. Mucosal IgA H pylori antibodies had a sensitivity of 98.5% (96.5-100) and a specificity of 91.7% (85.3-98.1), while for IgG these figures were, respectively, 88.3% (82.9-93.7) and 98.6% (95.9-100). As a diagnostic test mucosal IgA H pylori antibodies were comparable with culture and histology. CONCLUSION--Determination of local IgA and IgG H pylori antibody levels is a highly sensitive and specific test for the diagnosis of H pylori infection.     

Comparative evaluation of conventional methods and ELISA based IgG antibodies detection for diagnosis of Helicobacter pylori infection in cases of dyspepsia

Seventy five gastric biopsy specimens and 75 serum samples of same patients complaining of dyspepsia were collected. Biopsy specimens were processed for rapid urease test, gram staining and culture. Serum samples were used for detecting IgG antibodies against 128 kDa external protein (Cog A) of H. pylori using a commercially available ELISA kit. Rapid urease test was positive in 54 (72%), culture in 21 (28%) and gram staining in 15 (20%). Significant IgG levels were detected in 57 (76%) cases. It was therefore concluded that for diagnosis of H. pylori infection in cases of dyspepsia, determination of IgG levels can act as an important screening procedure.     

Impact of Helicobacter pylori infection on the humoral immune response to MUC1 peptide in patients with chronic gastric diseases and gastric cancer

Many investigators have demonstrated alteration of gastric mucins in H. pylori infected individuals. The inflammatory environment induced by H. pylori leading to aberrant glycosylation of MUC1 and demasking of core peptide MUC1 epitope could enhance immune responses to MUC1. IgG and IgM immune response to MUC1 in patients with gastric cancer (n = 214) chronic gastroduodenal diseases (n = 160) and healthy blood donors (n = 91) was studied with ELISA using bovine serum albumin-MUC1 60-mer peptide as antigen. H. pylori serologic status was evaluated with ELISA and CagA status by immunoblotting. Gastric mucosa histology was scored according to the Sydney system. Compared to H. pylori seronegative individuals, higher levels of IgG antibody to MUC1 were found in H. pylori seropositive patients with benign gastric diseases (p < 0.01) and blood donors (p < 0.03). Higher MUC1 IgG antibody levels were associated with a higher degree of gastric corpus mucosa inflammation in patients with chronic gastroduodenal diseases (p < 0.0025). There was a positive correlation between the levels of anti-H. pylori IgG and MUC1 IgG antibody levels in blood donors (p = 0.03), and in patients with benign diseases (p < 0.0001). In patients with gastric cancer (n = 214) a significantly higher level of anti-MUC1 IgG than in blood donors was observed (p < 0.001) irrespective of H. pylori status or stage of cancer. MUC1 IgM antibody levels were not related to the H. pylori serology. IgG immune response to tumor-associated MUC1 is up regulated in H. pylori infected individuals. This increase is associated with a higher IgG immune response to H. pylori and with a higher degree of gastric mucosa inflammation. High levels of MUC1 IgG antibody irrespective of H. pylori serologic status characterized patients with gastric cancer. The findings suggest that, in some individuals, the H. pylori infection may stimulate immune response to tumor-associated MUC1 peptide antigen thus modulating tumor immunity.     

Use of Helicobacter pylori-specific antibodies in the evaluation of intestinal metaplasia and gastric dysplasia

It is believed that Helicobacter pylori acts mainly during the initial phases of gastric carcinogenesis. Therefore, this study aims to assess the usefulness of H. pylori diagnosis in patients with chronic gastritis (CG), intestinal metaplasia (IM) and dysplasia--conditions that are associated with gastric cancer. A cross-sectional study of 94 patients was performed, which involved endoscopic biopsy and determination of specific serum anti-H. pylori antibodies (IgA, IgG and IgM) by enzyme-linked immunosorbent assay (ELISA). Biopsies were taken from the gastric antrum and corpus, and from endoscopic lesions. Two specimens per patient were used for bacterial culture. H. pylori infection status, used as the gold standard, was based on culture results. Validity measures were determined and receiver operating curve (ROC) was used to determine the best cut-off for serum antibody levels. Histopathological evaluation (n = 160) was performed independently by two pathologists. Lesions consistent with CG were found in 86 patients (91%), consistent with IM in 69 patients (73%) and with dysplasia in five patients (5%). In the 86 patients with CG, 38 (44%) were infected by H. pylori, as were 26 (38%) and one (20%) with IM and dysplasia, respectively (P=0.039). Area under the curve (AUC) was 0.40 (95% confidence interval [CI]: 0.28-0.51) for IgM, 0.69 (0.58-0.80) for IgA and 0.83 (0.74-0.92) for IgG for the diagnosis of H. pylori infection. Best cut-off was 41 u/mL for IgG, with a sensitivity (95% CI) of 90% (84-96%) and a negative predictive value (NPV) of 91% (85-97%). For IgA the results were 22 u/mL, 74% (65-83%) and 77% (68-86%), respectively. Prevalence of H. pylori appeared to decrease with increasing severity of the gastric lesion. In conclusion, it is suggested that non-invasive serological evaluation of anti-H. pylori (IgG) status after eradication therapy for peptic ulcer disease could be extended, after proper assessment of cut-off values and their validation, to the follow-up of patients with CG and IM.