Evaluation of a Novel Anti-H. pylori Antibody Detection Kit by Latex Turbidimetric Immunoassay.

BACKGROUND: While all modalities used for diagnosis of Helicobacter pylori (H. pylori) have demonstrated sufficient sensitivity and specificity, each test has advantages and limitations. The serum test for anti-H. pylori antibody with the latex method is noninvasive, easy, and inexpensive; it is thus a useful tool for mass-screening for H. pylori. In this study, we evaluated the utility of a newly developed latex kit, in comparison with other serum diagnostic kits based on enzyme-linked immunosorbent assay (ELISA). METHODS: In total, 187 subjects (77: H. pylori-positive, 75: H. pylori-negative, 35: previous infection with H. pylori) seen at Oita University Hospital during the period from January 1988 to September 2014 were enrolled in the study. All subjects were evaluated with 4 types of serum H. pylori antibody kits. One modality was based on the use of latex (Denka Kit, Denka Seiken Co., Ltd., Tokyo, Japan). Three kits were based on the use of ELISA. The E-Plate II Eiken (Eiken Chemical Co., Ltd., Tokyo, Japan) is henceforth referred to as Kit A. The Premier H. pylori kit (Meridian Bioscience, Inc., USA) is referred to as Kit B. The Platelia H. pylori IgG (Bio-Rad, Marnes-la-Coquette, France) is referred to as Kit C. RESULTS: Evaluation of 152 study participants, including some who were positive for H. pylori and some who were negative, sensitivity, specificity, and accuracy values were as follows: for the Denka kit, these values were, respec-tively, 92.2%, 93.3%, and 92.8%. For Kit A, these values were 88.3%, 100.0%, and 194.1%. For Kit B, these values were 98.7%, 76.0%, and 87.5%. For Kit C, these values were 98.7%, 80.0%, and 89.5%. The specificity of Kit A was > 90%. Sensitivity was > 90% for Kits B and C. For the Denka kit, both sensitivity and specificity were > 90%. Among the 35 subjects previously infected with H. pylori, the rate of positive diagnosis was 48.6% (17/35) with the Denka kit, 17.1% (6/35) with Kit A, 54.3% (19/35) with Kit B, and 54.3% (19/35) with Kit C. The rate of positive diagnosis was significantly higher with the Denka kit than with Kit A (p < 0.05). CONCLUSIONS: An assay based on use of the latex method, H. pylori-latex Seiken, demonstrated satisfactory sensitivity and specificity for detecting serum levels of H. pylori antibody. The performance of this kit was equivalent to that of ELISA kits currently used for the same purpose. This kit is therefore considered to be extremely suitable for diagnosis of H. pylori and mass-screening of patients at high risk for gastric cancer.

Promoting Immune Efficacy of the Oral Helicobacter pylori Vaccine by HP55/PBCA Nanoparticles against the Gastrointestinal Environment.

The immunogenicity of oral subunit vaccines is poor partly as a result of the harsh milieu of the gastrointestinal (GI) tract. For some pathogens that restrictedly inhabit the GI tract, a vaccine that works in situ may provide more potent protection than vaccines that operate parenterally. Yet, no appropriate delivery system is available for oral subunit vaccines. In this study, we designed HP55/poly( n-butylcyanoacrylate) (PBCA) nanoparticles (NPs) to carry Helicobacter pylori ( H. pylori) subunit vaccine CCF for oral administration in a prophylactic mice model. These NPs, which are synthesized using an interfacial polymerization method, protected the CCF antigen not only from the acidic pH in simulated gastric fluid (SGF, pH 1.2) but also from the proteolysis in simulated intestinal fluid (SIF, pH 7.4). Oral vaccination of mice with HP55/PBCA-CCF NPs promoted the production of serum antigen-specific antibodies, mucosal secretory IgA, and proinflammatory cytokines. Moreover, a Th1/Th17 response and augmented lymphocytes were found in the gastric tissue of HP55/PBCA-CCF NP-immunized mice, which might eventually limit H. pylori colonization. Collectively, these results indicate that HP55/PBCA NPs are promising carriers against the severe situation of the GI tract and thereby may be further utilized for other orally administrated vaccines or drugs.

Vaccine-mediated protection against Helicobacter pylori is not associated with increased salivary cytokine or mucin expression.

BACKGROUND: The development of an effective vaccine against Helicobacter pylori is impeded by the inability to reliably produce sterilizing immunity and our lack of knowledge regarding mechanisms of protective immunity against this pathogen. It has previously been described that salivary glands are essential for vaccine-mediated protection against H. pylori, but the mechanism responsible for this effect has not been identified. In this study we tested the hypothesis that vaccines reduce H. pylori colonization by inducing an immune-mediated change in salivary gland mucin secretion. MATERIALS AND METHODS: Sublingual and submandibular salivary glands were removed from untreated mice, from mice infected with H. pylori and from mice vaccinated against H. pylori then challenged with live bacteria. Cytokine levels in these salivary glands were quantified by ELISA, and salivary mucins were quantified by real-time PCR. Salivary antibody responses were determined by Western blot. RESULTS: Vaccine-mediated protection against H. pylori did not produce any evidence of a positive increase in either salivary cytokine or mucin levels. In fact, many cytokines were significantly reduced in the vaccinated/challenged mice, including IL-17A, IL-10, IL-1ß, as well as the mucin Muc10. These decreases were associated with an increase in total protein content within the salivary glands of vaccinated mice which appeared to be the result of increased IgA production. While this study showed that vaccination increased salivary IgA levels, previous studies have demonstrated that antibodies do not play a critical role in protection against H. pylori that is induced by current vaccine formulations and regimes. CONCLUSIONS: The effector mechanism of protective immunity induced by vaccination of mice did not involve immune changes within the salivary glands, nor increased production of salivary mucins.

Helicobacter pylori present in caries sample among dental caries patients.

Helicobacter pylori is Gram negative bacteria, the reason for causing peptic ulcer. There is suggestion between the presence of H. pylori in oral cavity and gastritis. The present study aimed to detect H. pylori in dental caries samples. The study included 29 dental caries patients from both sexes (13 males and 16 females), with different age groups (children and adult), and nine apparently healthy subject as a control group (2 males & 7 females). Dental caries samples were collected and investigated for this study from patients with dental caries who visited the Dental Faculty in the College of Dentistry, University of Babylon, Iraq. H. pylori antigen was detected using an enzyme linked immunosorbent assay (ELISA) technique. Of the 29 dental caries patients, 19 (65.51%) patients were positive for H. pylori antigen test. Most of them were in the age group 20-30 (9 patients) & 30-40 (8 patients). The age groups (10-20) & (40-50) years shows 100% positivity for H. pylori antigen. Also, result was recorded significant higher difference's between H. pylori positive antigen between dental caries patients and H. pylori positive antigen among control group. (t=2.697,df=5, p≤ 0.05). Pearson correlation recorded significantly higher association between the presence of H. pylori antigen and the dental caries infection among test group (r=1, p≤ 0.000), 4 (44.5%) of the 9 control subjects, without dental caries, were positive for H. pylori antigen test. In summary, the H. pylori positive antigen test was recorded in both dental caries patients (65.51%) and in the control group (62.5 %). In conclusion, H. pylori antigen was present in dental caries patients. This could indicate that the bacteria H. pylori present in dental caries samples may contribute to caries processes.

Immunoinformatics design and synthesis of a multi-epitope vaccine against Helicobacter pylori based on lipid nanoparticles.

Helicobacter pylori (H. pylori) is responsible for various chronic or acute diseases, such as stomach ulcers, dyspepsia, peptic ulcers, gastroesophageal reflux, gastritis, lymphoma, and stomach cancers. Although specific drugs are available to treat the bacterium's harmful effects, there is an urgent need to develop a preventive or therapeutic vaccine. Therefore, the current study aims to create a multi-epitope vaccine against H. pylori using lipid nanoparticles. Five epitopes from five target proteins of H. pylori, namely, Urease, CagA, HopE, SabA, and BabA, were used. Immunogenicity, MHC (Major Histocompatibility Complex) bonding, allergenicity, toxicity, physicochemical analysis, and global population coverage of the entire epitopes and final construct were carefully examined. The study involved using various bioinformatic web tools to accomplish the following tasks: modeling the three-dimensional structure of a set of epitopes and the final construct and docking them with Toll-Like Receptor 4 (TLR4). In the experimental phase, the final multi-epitope construct was synthesized using the solid phase method, and it was then enclosed in lipid nanoparticles. After synthesizing the construct, its loading, average size distribution, and nanoliposome shape were checked using Nanodrop at 280 nm, dynamic light scattering (DLS), and atomic force microscope (AFM). The designed vaccine has been confirmed to be non-toxic and anti-allergic. It can bind with different MHC alleles at a rate of 99.05%. The construct loading was determined to be about 91%, with an average size of 54 nm. Spherical shapes were also observed in the AFM images. Further laboratory tests are necessary to confirm the safety and immunogenicity of the multi-epitope vaccine.

Nanobody-based immunosensor for the detection of H. pylori in saliva.

Helicobacter pylori (H. pylori) infection is highly prevalent worldwide, affecting more than 43% of world population. The infection can be transmitted through different routes, like oral-oral, fecal-oral, and gastric-oral. Electrochemical sensors play a crucial role in the early detection of various substances, including biomolecules. In this study, the development of nanobody (Nb)-based immunosensor for the detection of H. pylori antigens in saliva samples was investigated. The D2_Nb was isolated and characterized using Western blot and ELISA and employed in the fabrication of the immunosensor. The sensor was prepared using gold screen-printed electrodes, with the immobilization of Nb achieved through chemical linkage using cysteamine-glutaraldehyde. The surface of the electrode was characterized using EIS, FTIR and SEM. Initially, the Nb-based immunosensor's performance was evaluated through cyclic voltammetry (CV), differential pulse voltammetry (DPV), and square wave voltammetry (SWV). The sensor exhibited excellent linearity with an R2 value of 0.96. However, further assessment with the DPV technique revealed both a low limit of detection (5.9 ng/mL, <1 cfu/mL) and high selectivity when exposed to a mixture of similar antigens. Moreover, the immunosensor demonstrated robust recovery rates (96.2%-103.4%) when spiked into artificial saliva and maintained its functionality when stored at room temperature for 24 days.

Association of Helicobacter pylori positivity with the symptoms in patients with hyperemesis gravidarum.

PURPOSE: To investigate the relationship between Helicobacter pylori (Hp) positivity and the severity of symptoms of nausea and vomiting in patients diagnosed with hyperemesis gravidarum (HG). DESIGN: Prospective controlled. METHODS: Ninety patients with the diagnosis of HG below the 20th week gestation, who had no additional disease and 50 pregnant women with no complaints were enrolled in the study. According to the severity of symptoms, the patients were divided into three groups as group I, II and III (mild, moderate and severe, respectively). The Rhode's scoring system was used to determine the severity of HG symptoms. HpIgG and IgM levels were determined in the blood samples and Hp DNA positivity with PCR was investigated in the saliva. RESULTS: In accordance with the Rhode's scoring system, 15.5 % of the pregnant women had mild, 58.9 % had moderate, and 25.6 % had severe symptoms (group I, II and III, respectively). HpIgG was determined as positive in 78.6, 84.9 and 82.6 % in groups I, II and III, respectively. HpIgM positivity was determined as 26.1 % only in group III (p = 0.847). HpDNA was determined as 7.2, 3.8, and 91.3 % in group I, II, and III, respectively (p<0.01). While HpIgG was positive in 60 %, HpDNA was found to be positive in 2 % and HpIgM was found to be negative in all the pregnant women in the control group. CONCLUSION: A positive relationship between the symptoms of HG and Hp positivity was determined using PCR.

[Clinical and pathogenetic significance of collagen metabolism disorder in children with gastroesophageal reflux disease].

In 62 children with gastroesophageal reflux disease (GERD) and 32 with gastroduodenitis (DG) aged 9-17 years, the peculiarities of metabolism of collagen were studied. High levels of fractions of sialic acids were set, that was associated with the protein fructose, fractions of hydroxyproline in children with GERD compared with the patients with DG, which testify to the process of degradation of collagen and may be one of the factors contributing to the local inflammation of the esophagus and gastroduodenal zone of the digestive tract. The prevalence of Helicobacter pylori, as well as violations of diet, play an important role in maintaining the inflammatory process.

The role of environmental factors in autoimmune thyroiditis.

Environmental factors can play an important role in the development of autoimmune thyroiditis (AT) and other autoimmune diseases. This article reviews the role of heavy metals and infectious agents in AT. Currently, the genes responsible for a metal-induced pathology are known in experimental animals but similar knowledge is lacking in man. Metals such as nickel or mercury induce delayed type T cell hypersensitivity (allergy) which is relatively common, especially in women. T-cell allergy can be studied with the lymphocyte transformation test, LTT-MELISA. It has been found that patients with AT and other autoimmune diseases, such as multiple sclerosis, psoriasis, systemic lupus erythematosus and atopic eczema, show increased lymphocyte reactivity in vitro to inorganic mercury, nickel and other metals compared to healthy controls. The important source of mercury is dental amalgam. Replacement of amalgam in mercury-allergic subjects resulted in improvement of health in about 70% of patients. Several laboratory parameters such as mercury-specific lymphocyte responses in vitro and anti-thyroid autoantibodies were normalized as well. In contrast, no changes in health and laboratory results were observed in mercury-allergic patients who did not have their amalgams replaced. The same was true for non-allergic patients who underwent amalgam replacement. Infectious agents such as Helicobacter pylori (Hp) may cause chronic inflammation and autoimmune reactivity in susceptible subjects. The results of in vitro experiments performed with lymphocytes from Hp infected patients indicate that Hp can cause immunosuppression which might be eliminated by successful eradication therapy. In conclusion, heavy metals and Hp infection may play an important role in AT. Laboratory tests, such as LTT-MELISA, can help to determine the specific etiological agents causing inflammation in individual patients. The treatment of AT and other autoimmune diseases might be improved if such agents are eliminated and any future exposure restricted.

Nanohybrid-based immunosensor prepared for Helicobacter pylori BabA antigen detection through immobilized antibody assembly with @ Pdnano/rGO/PEDOT sensing platform.

The gastric colonization of human hosts by Helicobacter pylori (H. pylori) increases the risk of developing gastritis, ulcers and gastric cancer. To detect H. pylori, a nanohybrid-based BabA immunosensor is developed herein. BabA is an outer membrane protein and one of the major virulence factors of H. pylori. To design the immunosensor, an Au electrode is loaded with palladium nanoparticles (Pdnano) by electrodeposition to generate reduced graphene oxide (rGO)/poly(3,4-ethylenedioxythiophene) (PEDOT). The immobilization of these nanostructured materials imparts a large surface area and electroconductivity to bio-immune-sensing molecules (here, the BabA antigen and antibodies). After optimization, the fabricated immunosensor has the ability to detect antigens (H. pylori) in a linear range from 0.2 to 20 ng/mL with a low LOD (0.2 ng/mL). The developed immunosensor is highly specific, sensitive and reproducible. Additionally, in silico methods were employed to better understand the hybrid nanomaterials of the fabricated Pdnano/rGO/PEDOT/Au electrode. Simulations performed by molecular docking, and Metropolis Monte Carlo adsorption studies were conducted. The results revealed that the hybrid nanomaterials exhibit a stable antigen-antibody complex of BabA, yielding the lowest binding energy in relation to the electrode materials, emphasizing the functionality of the constructed electrodes in the electrochemical immunosensor.

Characterizing the polymeric status of Helicobacter pylori heat shock protein 60.

Helicobacter pylori heat shock protein 60 (HpHsp60) was first identified as an adhesion molecule associated with H. pylori infection. Here we have analyzed the structure of HpHsp60 via amino acid BLAST, circular dichroism, and electrophoresis and the results indicate that most recombinant HpHsp60 molecules exist as dimers or tetramers, which is quite different from Escherichia coli Hsp60. Treatment of human monocytic cells THP-1 with HpHsp60 was found to up-regulate a panel of cytokines including IL-1alpha, IL-8, IL-10, IFN-gamma, TNF-alpha, TGF-beta, GRO, and RANTES. Carboxymethylated HpHsp60 molecules with a switched oligomeric status were able to further enhance NF-kappaB-mediated IL-8 and TNF-alpha secretion in THP-1 cells compared to unmodified HpHsp60 molecules. These results indicated that the oligomeric status of HpHsp60s might have an important role in regulating host inflammation and thus help facilitate H. pylori persistent infection.

Salivary anti-Helicobacter pylori positivity among endoscopy patients with chronic liver disease.

In this study, endoscopy patients with and without chronic liver disease (CLD) were examined and tested for Helicobacter pylori infection by detecting the presence of serum and salivary anti-H. pylori antibody. The validity of these measures was compared with Campylobacter-like organism analysis (gold standard) performed on patients requiring gastric biopsy. Among 114 patients with CLD and 50 without, the commonest endoscopy diagnosis was gastritis (27.2%). Salivary H. pylori positivity was significantly associated with older age. Salivary anti-H. pylori antibody positivity showed low sensitivity (36.6%) and high specificity (75.8%) in CLD patients.

Synergistic effect of 2D material coated Pt nanoparticles with PEDOT polymer on electrode surface interface for a sensitive label free Helicobacter pylori CagA(Ag-Ab) immunosensing.

Helicobacter pylori (H. pylori) immunosensor based on platinum nanoparticles/poly(3,4-ethylenedioxythiophene)/reduced graphene oxide (Ptnano/PEDOT/red-GOx) modified gold electrode (Au-ET) was stepwise fabricated for the detection of cytotoxin-associated gene A antibody (CagA antibody). H. pylori is a microaerophillic and a Gram-negative bacteria that causes gastric ulcer leading eventually to adenocarcinoma (gastric cancer) in the later stage. H. pylori colonizes inner lining of human stomach. The developed diagnostic sensing interface would allow H. pylori (stomach infection) detection in early stage and would be a great contribution in clinical laboratories. In order to fabricate the immunosensor, CagA antigen was immobilized over the Ptnano/PEDOT/red-GOx modified Au-ET. Afterwards, the modified electrode was used for immuno-sensing of H. pylori specific Cag A antibodies in serum. At lower voltage the modified Ptnano/PEDOT/red-GOx/Au-ET shows an amplified sensing at the interface that makes the sensor more sensitive and specific. CagA is a virulence factor produced by H. pylori was determined by sudden decrease in the current. The laboratory synthesized nano composites were characterised by Scanning Electron Microscopy (SEM) and Atomic force microscopy (AFM) studies. The sensor had excellent linear range of 0.1 ng/ml to 30 ng/ml by limiting the detection range up to 0.1 ng/ml. Moreover, the novel immunosensor formed had good accuracy, precision and reliability. The immunosensor also showed an excellent storage stability by retaining 60-70% of its initial activity until 60 days kept at 4 °C. Highly sensitive interface of CagA antigen@Ptnano/PEDOT/red-GOx/Au-ET shows a promising future for H. pylori detection in diagnosis of stomach ulcer and stomach cancer.

Prevalence of Helicobacter pylori in asymptomatic subjects--a nested PCR based study.

The aim of the study was to see the prevalence of Helicobacter pylori in asymptomatic children and adults by using nested PCR which is considered to be more specific than serological methods. Saliva and stool samples of 137 healthy children (aged 8 months to 16 y) and 108 asymptomatic adults (aged 17-60 y) were collected. PCR with primers targeting Hsp60 gene sequence of H. pylori was used. H. pylori positivity with nested PCR was observed in 45.7% (112/245) of the saliva and 42.8% (105/245) of the stool specimens. Prevalence of H. pylori in saliva was found to be 2.1%, 22.7%, 55.9%, 56.0%, 68.9% and 62.9% in the age groups of < 5 y, 6-10 y, 11-16 y, 17-30 y , 31-45 y and 45-60 y, respectively. The detection rates in stool were 4.25% in < 5 y, 13.64% in 6-10 y, 50% in 11-16 y, 64% in 17-30 y, 58.62% in 31-45 y and 61.1% in 45-60 y of age groups. The most favourable age group for acquiring the infection was 11-16 y. H. pylori positivity increased with lowering of socioeconomic status. There was no gender bias in prevalence of the bacterium.

The relationship between the helicobacter pylori seropositivity with systemic and local oxidative status and hyperemesis gravidarum: a pilot study.

OBJECTIVES: The aim of study was to determine the helicobacter pylori (HP) seropositivity and oxidative parameters in serum and saliva of pregnant women with poor oral hygiene and hyperemesis gravidarum (HG). METHODS: A case-control study was conducted involving 50 pregnant women in their first trimester of pregnancy. Twenty-five subjects had a diagnosis of HG, and remaining 25 were healthy pregnant women who served as control subjects were included. The groups were adjusted for age, parity and gestational week. All patients were subjected to the measurement of total oxidant status (TOS) and total antioxidant status in serum and saliva. Also HP seropositivity was investigated. RESULTS: Serum TAS and TOS values were similar, although oxidative burden in saliva of women with HG were significantly higher than controls. HP seropositivity was found to be 24% in women with HG and 4% of controls. CONCLUSIONS: Our results suggest that significantly increased oxidative burden and slightly decreased antioxidative capacity of saliva may be involved in the pathogenesis of HG and this condition may be the result of HP infection which was found to be significantly more common in women with poor oral hygiene and HG.

Association of common chronic infections with coronary artery disease in patients without any conventional risk factors.

BACKGROUND & OBJECTIVES: Report from the west suggest an association of infections and inflammation with atherosclerotic coronary artery disease (CAD). Entire microbial burden from several simultaneous chronic infections could be more important than a single infection in promoting atherosclerosis. No study has been done in Indian population, investigating the association of various chronic infections with CAD. We therefore evaluated the presence of markers of chronic infections in CAD patients having no conventional risk factors and healthy individuals in a tertiary care hospital in north India. METHODS: Seropositivity to IgG antibodies was investigated for Chlamydia pneumoniae, Mycoplasma pneumoniae, and Helicobacter pylori in 30 CAD patients with no conventional risk factors scheduled for coronary artery bypass surgery and in healthy blood donors. Periodontal pathogens were isolated by aerobic and anaerobic culture. RESULTS: All patients except one were < 55 yr of age and six were younger than 40 yr. Seropositivity to C. pneumoniae was significantly higher in CAD patients than healthy controls (63.3 vs. 23.3%, P<0.01). Combined seropositivity to both C. pneumoniae and M. pneumoniae was significantly higher in CAD patients with myocardial infarction (MI) than those without MI (61.5 vs. 11.8%, P<0.05). Aerobic and anaerobic cultures for the isolation of periodontal pathogens were positive in seven patients and five healthy blood donors. INTERPRETATION & CONCLUSION: C. pneumoniae seropositivity was significantly higher (P<0.001) in CAD patients without any of the conventional risk factors for CAD. Combined seropositivity to C. pneumoniae and M. pneumoniae was significantly higher (P<0.05) in CAD patients with MI than in those without MI. Possibly CAD in young is not (or less) governed by conventional risk factors, and infectious agents can be potential risk factors for the development of atherosclerosis and CAD in this subset of patients.

Oral Helicobacter pylori vaccine-encapsulated acid-resistant HP55/PLGA nanoparticles promote immune protection.

Oral vaccination, is notoriously weak or nonimmunogenic. One of the major reasons is the inefficient antigen uptake caused by enzymolysis and hydrolysis in the gastrointestinal tract. In this study, acid-resistant HP55/PLGA nanoparticle was developed as an oral delivery system to protect H. pylori recombinant antigen CCF against the complex gastrointestinal environment. These ∼200nm particles controlled the release of antigen in the acidic environment (pH⩽5.5). Immunized mice with HP55/PLGA-CCF nanoparticles induced high levels of urease-specific antibodies and memory T cell responses. A month after H. pylori challenge, 43% of mice were completely protected. The protection was highly associated with the Th1/Th17-bias immune response, which had been recognized as an optimal immunity against H. pylori infection. In addition, a mass of T-cells were observed in the lamina propria of mice immunized with CCF, especially in the HP55/PLGA-CCF nanoparticles administered recipients, and contributed to the development of postimmunization gastritis. These results indicate that oral immunization with acid-resistant HP55/PLGA nanoparticles encapsulating vaccine antigens represent a promising strategy for antigen protection, slow-release and targeting, and thus prevented gastrointestinal infection.

ABH and Lewis antigen distributions in blood, saliva and gastric mucosa and H pylori infection in gastric ulcer patients.

AIM: To investigate the ABH and Lewis antigen expression in erythrocytes, saliva and gastric epithelium, as well as the association between H pylori and the presence of gastric epithelial lesions. METHODS: The distribution of ABH and Lewis blood group antigens in erythrocytes, saliva and gastric mucosa of H pylori-infected gastric ulcer patients was analyzed. Forty-two patients with gastric ulcer were studied, and fifty healthy individuals were used as control group. The blood group antigens were determined by direct hemagglutination, dot-ELISA and immunohistochemical methods in erythrocytes, saliva and gastric mucosa specimens, respectively. Diagnosis for H pylori infection was performed by conventional optical microscopy and ELISA. RESULTS: A higher seroprevalence of IgG H pylori specific antibodies was observed in gastric ulcer patients (90%) compared to the control group (60%). We observed a significant increase of phenotypes O, A2 and Lewis b in H pylori-infected patients. The expression of these antigens had progressive alterations in areas of ulcerous lesions and intestinal metaplasia. CONCLUSION: ABH and Lewis blood group antigens are a good indicator for cellular alterations in the gastric epithelium.

Developing a Salivary Antibody Multiplex Immunoassay to Measure Human Exposure to Environmental Pathogens.

The etiology and impacts of human exposure to environmental pathogens are of major concern worldwide and, thus, the ability to assess exposure and infections using cost effective, high-throughput approaches would be indispensable. This manuscript describes the development and analysis of a bead-based multiplex immunoassay capable of measuring the presence of antibodies in human saliva to multiple pathogens simultaneously. Saliva is particularly attractive in this application because it is noninvasive, cheaper and easier to collect than serum. Antigens from environmental pathogens were coupled to carboxylated microspheres (beads) and used to measure antibodies in very small volumes of human saliva samples using a bead-based, solution-phase assay. Beads were coupled with antigens from Campylobacter jejuni, Helicobacter pylori, Toxoplasma gondii, noroviruses (G I.1 and G II.4) and hepatitis A virus. To ensure that the antigens were sufficiently coupled to the beads, coupling was confirmed using species-specific, animal-derived primary capture antibodies, followed by incubation with biotinylated anti-species secondary detection antibodies and streptavidin-R-phycoerythrin reporter (SAPE). As a control to measure non-specific binding, one bead set was treated identically to the others except it was not coupled to any antigen. The antigen-coupled and control beads were then incubated with prospectively-collected human saliva samples, measured on a high throughput analyzer based on the principles of flow cytometry, and the presence of antibodies to each antigen was measured in Median Fluorescence Intensity units (MFI). This multiplex immunoassay has a number of advantages, including more data with less sample; reduced costs and labor; and the ability to customize the assay to many targets of interest. Results indicate that the salivary multiplex immunoassay may be capable of identifying previous exposures and infections, which can be especially useful in surveillance studies involving large human populations.

Detection of Helicobacter pylori urease antigen in saliva in patients with different gastric H. pylori status.

BACKGROUND: Finding a simple, accurate, and noninvasive diagnosis method is a substantial challenge for the detection of Helicobacter pylori. The aim of the present study was to compare the presence of H. pylori urease antigen in saliva with the presence of this bacterium in gastric mucosa. METHODS: Saliva samples and gastric biopsies were taken from 153 consenting Moroccan patients. Saliva samples were analyzed using an immunochromatographic test for urease antigen H. pylori detection. Thereafter, the gastric biopsies were analyzed by histology and polymerase chain reaction (PCR) to detect this bacterium. RESULTS: From a total of 153 recruited Moroccan patients, H. pylori was detected in 28 (18.30%), 87 (57.24%), and 69 (45.10%) cases by saliva test, histology, and PCR, respectively. A significant association was observed between the presence of H. pylori antigen in saliva and age. However, no association was found with sex, H. pylori virulence factors, gastric disease outcome, and density of the bacterium on the gastric mucosa. Considering that only 90 patients presented concordant results on H. pylori diagnosis (positive or negative) by both histology and PCR, the immunochromatographic test showed very low sensitivity (29.79%) and high specificity (90.70%). Of these two tests, the positive and negative predictive values were 77.78% and 54.17%, respectively. The accuracy of the test for salivary detection of urease antigen H. pylori was 58.89%. CONCLUSION: This study demonstrated a low detection rate of H. pylori antigens in saliva compared with the presence of this bacterium in gastric mucosa, suggesting that saliva cannot be used as a suitable sample for the diagnosis of H. pylori in our study population.