Local and systemic immune and inflammatory responses to Helicobacter pylori strains

Investigating associations between HLA DQA1 ~ DQB1 haplotypes, H. pylori infection, metaplasia, and anti-CagA IgA seropositivity in a Turkish gastritis cohort

Helicobacter pylori was reported as an important cause of gastritis, and gastric ulcers and CagA oncoprotein-producing H. pylori subgroups were blamed to increase the severity of gastritis. Disparities were reported in that the presence of serum anti-CagA IgA was not parallel with CagA-positive H. pylori cohabitation. We hypothesized that the HLA-DQA1 ~ DQB1 haplotypes in human populations include protective haplotypes that more effectively present immunogenic CagA peptides and susceptible haplotypes with an impaired capacity to present CagA peptides. We recruited patients (n = 201) admitted for gastroendoscopy procedures and performed high-resolution HLA-DQA1 and DQB1 typing. Serum anti-CagA IgA levels were analyzed by ELISA (23.0% positive), and H. pylori was classified as positive or negative in gastric mucosal tissue slides (72.6% positive). The HLA DQA1*05:05 allele (29.1%) and HLA DQB1*03:01 allele (32.8%) were found at the highest frequency among gastritis patients of Turkish descent. In HLA DQA1*05:05 ~ DQB1*03:01 double homozygous (7.3%) and heterozygous (40.7%) haplotype carriers, the presence of anti-CagA IgA decreased dramatically, the presence of H. pylori increased, and the presence of metaplasia followed a decreasing trend. The DQ protein encoded by HLA DQA1*05:05-DQ*03:01 showed a low binding affinity to the CagA peptide when binding capacity was analyzed by the NetMHCIIPan 4.0 prediction method. In conclusion, HLA DQA1 ~ DQB1 polymorphisms are crucial as host defense mechanisms against CagA H. pylori since antigen binding capacity plays a crucial role in anti-CagA IgA production.

Host immune response mediates changes in cagA copy number and virulence potential of Helicobacter pylori

Helicobacter pylori is the major risk factor for gastric cancer. H. pylori harboring the type IV secretion system (T4SS) and its effector CagA encoded on the cag pathogenicity Island (cagPAI) increases the risk. H. pylori PMSS1 has a multi-cagA genotype, modulating cagA copy number dynamically from zero to four copies. To examine the effect of the immune response on cagA copy number change, we utilized a mouse model with different immune status. PMSS1 recovered from Rag1-/- mice, lacking functional T or B cells, retained more cagA copies. PMSS1 recovered from Il10-/- mice, showing intense inflammation, had fewer cagA copies compared to those recovered from wild-type mice. Moreover, cagA copy number of PMSS1 recovered from wild-type and Il10-/- mice was positively correlated with the capacity to induce IL-8 secretion at four weeks of infection. Since recombination in cagY influences T4SS function, including CagA translocation and IL-8 induction, we constructed a multiple linear regression model to predict H. pylori-induced IL-8 expression based on cagA copy number and cagY recombination status; H. pylori induces more IL-8 secretion when the strain has more cagA copies and intact cagY. This study shows that H. pylori PMSS1 in mice with less intense immune response possess higher cagA copy number than those infected in mice with more intense immune response and thus the multi-cagA genotype, along with cagY recombination, functions as an immune-sensitive regulator of H. pylori virulence.

Infection by CagA-Positive Helicobacter pylori Strains and Bone Fragility: A Prospective Cohort Study

Helicobacter pylori (HP) infection is a common and persistent disorder acting as a major cofactor for the development of upper gastrointestinal diseases and several extraintestinal disorders including osteoporosis. However, no prospective study assessed the effects of HP on bone health and fracture risk. We performed a HP screening in a population-based cohort of 1149 adults followed prospectively for up to 11 years. The presence of HP infection was assessed by serologic testing for serum antibodies to HP and the cytotoxin associated gene-A (CagA). The prevalence of HP infection did not differ among individuals with normal bone mineral density (BMD), osteoporosis, and osteopenia. However, HP infection by CagA-positive strains was significantly increased in osteoporotic (30%) and osteopenic (26%) patients respect to subjects with normal BMD (21%). Moreover, anti-CagA antibody levels were significantly and negatively associated with lumbar and femoral BMD. Consistent with these associations, patients affected by CagA-positive strains had a more than fivefold increased risk to sustain a clinical vertebral fracture (HR 5.27; 95% CI, 2.23-12.63; p < .0001) and a double risk to sustain a nonvertebral incident fracture (HR 2.09; 95% CI, 1.27-2.46; p < .005). Reduced estrogen and ghrelin levels, together with an impaired bone turnover balance after the meal were also observed in carriers of CagA-positive HP infection. HP infection by strains expressing CagA may be considered a risk factor for osteoporosis and fractures. Further studies are required to clarify in more detail the underlying pathogenetic mechanisms of this association. © 2020 American Society for Bone and Mineral Research (ASBMR).

Relationship Between Helicobacter pylori Infection, Serum Vitamin D3 Level and Spontaneous Abortion

Background

The effects of vitamin D3 (VD3) on pregnancy outcomes remain obscure. Thus, this study aims to investigate the relationship between maternal H. pylori infection, low VD3 level, and spontaneous abortion.

Methods

This research is conducted in Shahid Ali Qader Consultant Clinic in Sulaimaniyah city in which 100 women with a history of abortion and 100 women with no history of miscarriage were included. Serum detection of anti-H. pyloriIgG, IgA, and VD3 were done using enzyme-linked immunosorbent assay (ELISA) technique.

Results

The mean of VD3, H. pylori IgG, and IgAin patients and control group cases was determined and analyzed statistically.

Conclusion

H. pylori infection and VD3 play a significant role in early pregnancy loss. Blood group A and O are more prone to spontaneous abortion.

Effect of familiarity and mixing method on gestating sow welfare and productivity in large dynamic groups

The objectives of this study were twofold: first, to investigate the effects of sow familiarity prior to mixing into a larger dynamic group of gestating sows and, second, to examine the impact of how the sows entered the pen during this mixing event. The cohort of sows was either familiar with each other because of premixing (PMIX) or unfamiliar (UMIX). This PMIX or containment of sows in a stall (UMIX), occurred from weaning until the sows were mixed into the large gestation pen 8 d later. The cohort of incoming sows was introduced either as a batched unit (BAT) or new sows were introduced into the dynamic group singly (IND) though the electronic sow feeder. Lesion severity and quantity score, lameness, and body condition score (BCS) were tracked throughout the entire gestation period for 213 sows. Overall, there was little effect of the treatment but a strong impact of parity on the outcomes. Younger animals had significantly higher risk for lesions (P < 0.001) and higher risk for more severe lesions (P < 0.001) than higher parity animals. Lower parity had an association with the risk of lameness (P < 0.05), but it had no significant effect on BCS (P > 0.05). The risk of lameness increased on days 15 and 62 compared to weaning (P < 0.001). Risk of low BCS decreased on days 62 and 113 relative to scores at weaning (P < 0.001). A degree of familiarity by day interaction was present for lesion quantity (P < 0.001) and lesion severity (P < 0.001). The risk of more lesions was higher in the premixed groups before going into the dynamic group, but equilibrated with the unmixed group after day 11, 3 d in the large dynamic pen. The highest risk for the greatest quantity of lesions peaked at day 11 then declined, but never reached the lowest level again which was measured at weaning. Despite the variability in the welfare measures, there was no significant impact of treatment or parity on sow productivity. In conclusion, our data demonstrate that a period of premixing sows and varying the method of entering sows into the pen did not have a long-term impact on the welfare of the sows or on their productivity.

When is Helicobacter pylori acquired in populations in developing countries? A birth-cohort study in Bangladeshi children

Helicobacter pylori colonization is prevalent throughout the world, and is predominantly acquired during childhood. In developing countries, >70% of adult populations are colonized with H. pylori and >50% of children become colonized before the age of 10 years. However, the exact timing of acquisition is unknown. We assessed detection of H. pylori acquisition among a birth cohort of 105 children in Mirzapur, Bangladesh. Blood samples collected at time 0 (cord blood), and at 6, 12, 18, and 24 months of life were examined for the presence of IgG and IgA antibodies to whole cell H. pylori antigen and for IgG antibodies to the CagA antigen using specific ELISAs and immunoblotting. Breast milk samples were analyzed for H. pylori-specific IgA antibodies. Cord blood was used to establish maternal colonization status. H. pylori seroprevalence in the mothers was 92.8%. At the end of the two-year follow-up period, 50 (47.6%) of the 105 children were positive for H. pylori in more than one assay. Among the colonized children, CagA prevalence was 78.0%. A total of 58 children seroconverted: 50 children showed persistent colonization and 8 (7.6%) children showed transient seroconversion, but immunoblot analysis suggested that the transient seroconversion observed by ELISA may represent falsely positive results. Acquisition of H. pylori was not influenced by the mother H. pylori status in serum or breastmilk. In this population with high H. pylori prevalence, we confirmed that H. pylori in developing countries is detectable mainly after the first year of life.

Proinflammatory Cytokine IL-17 Shows a Significant Association with Helicobacter pylori Infection and Disease Severity

Background

The pro- and anti-inflammatory cytokines play an important role in the immune response against H. pylori infection. The proinflammatory cytokines of Th17 cells have been suggested to play a major role in H. pylori infection and resulting gastric inflammation.

Objective

The objective of this study was to compare the expression of selected inflammatory cytokines (IL-10, IL-17, IL-21, IL-23, and TNF-α) in H. pylori-infected patients and healthy controls and to understand their association with H. pylori infection and disease severity.

Results

The expression levels of IL-17 and IL-23 were significantly higher in H. pylori-infected patients. The expression of IL-21 was also higher in H. pylori-positive patients but there was no significant association with infection. IL-17 expression showed a significant increase with the severity of chronic gastritis.

Conclusion

The proinflammatory cytokine, IL-17, shows a significant association with H. pylori infection and disease severity in a Sri Lankan dyspeptic patient population.

Helicobacter pylori colonization and pregnancies complicated by preeclampsia, spontaneous prematurity, and small for gestational age birth

BACKGROUND

Preeclampsia (PE), small for gestational age (SGA), and spontaneous preterm birth (PTB) each may be complications of impaired placental function in pregnancy. Although their exact pathogenesis is still unknown, certain infectious agents seem to play a role. Helicobacter pylori (H. pylori) colonization has been associated with increased risk for PE. Our aim was to assess the association between H. pylori colonization and PE, SGA, and PTB.

MATERIAL AND METHODS

We measured IgG anti-H. pylori and CagA antibodies in serum of pregnant women (median 20.5 weeks, range 16.5-29.4) who participated in a population-based prospective cohort study. Delivery and medical records were assessed. Information on demographics, education, and maternal risk factors was collected by questionnaire. We used multivariate logistic regression analyses to assess associations between H. pylori colonization and PE, SGA, and PTB.

RESULTS

In total, 6348 pregnant women were assessed. H. pylori positivity was found in 2915 (46%) women, of whom 1023 (35%) also were CagA-positive. Pregnancy was complicated by PE, SGA, or PTB in 927 (15%) women. H. pylori colonization was associated with PE (aOR 1.51; 95%CI 1.03-2.25). Differentiation according to CagA status revealed the same risk. H. pylori was positively related with SGA, mainly explained by CagA-positive strains (aOR 1.34; 1.04-1.71). No association was observed between H. pylori and PTB.

CONCLUSIONS

Our data suggest that H. pylori colonization may be a risk factor for PE and SGA. If these associations are confirmed by future studies and shown to be causal, H. pylori eradication may reduce related perinatal morbidity and mortality.

In situ visualization of plasma cells producing antibodies reactive to Porphyromonas gingivalis in periodontitis: the application of the enzyme-labeled antigen method

Porphyromonas gingivalis is a keystone periodontal pathogen. Histologocally, the gingival tissue in periodontitis shows dense infiltration of plasma cells. However, antigens recognized by antibodies secreted from the immunocytes remain unknown. The enzyme-labeled antigen method was applied to detecting plasma cells producing P. gingivalis-specific antibodies in biopsied gingival tissue of periodontitis. N-terminally biotinylated P. gingivalis antigens, Ag53 and four gingipain domains (Arg-pro, Arg-hgp, Lys-pro and Lys-hgp) were prepared by the cell-free protein synthesis system using wheatgerm extract. With these five labeled proteins as probes, 20 lesions of periodontitis were evaluated. With the AlphaScreen method, antibodies against any one of the five P. gingivalis antigens were detected in 11 (55%) serum samples and 17 (85%) tissue extracts. Using the enzyme-labeled antigen method on paraformaldehyde-fixed frozen sections of gingival tissue, plasma cells were labeled with any one of the five antigens in 17 (94%) of 18 specimens, in which evaluable plasma cells were detected. The positivity rates in periodontitis were significantly higher than those found previously in radicular cysts (20% in sera and 33% in tissue extracts with the AlphaScreen method, and 25% with the enzyme-labeled antigen method). Our findings directly indicate that antibodies reactive to P. gingivalis are locally produced in the gingival lesions, and that inflammatory reactions against P. gingivalis are involved in periodontitis.

Correlation of serum anti-helicobacter pylori immunoglobulin a (IgA) with histological parameters of chronic gastritis in ibadan, Nigeria

BACKGROUND

The seroprevalence of anti-H. pylori IgA antibodies has been reported to vary among populations and in relation to strains of Helicobacter pylori bacterium. However, there has been conflicting reports on the association between IgA serological status and the histological variables of chronic gastritis. This study was therefore conducted to clarify this relationship.

METHOD

Using an ELISA based commercial kit, anti-H. pylori IgA antibody tests were performed on 65 dyspeptic patients and 65 age- and sex-matched controls. The gastric biopsies of these patients were also examined histologically for the degrees of inflammation, activity, intestinal metaplasia and atrophy. The CagA status of the patients had been determined previously.

RESULTS

There was an anti-H. pylori IgA antibody prevalence of 67.7% in dyspeptics and 56.9% in non-dyspeptic individuals. No correlations were observed between serum H. pylori IgA antibody and the graded parameters of chronic gastritis in dyspeptic patients, although twice more patients with mild gastric inflammation were found among IgA positive than among IgA negative patients. However, a statistically significant relationship was established between serum IgA positivity and the CagA status of the patients (p = 0.028).

CONCLUSION

The seroprevalence of anti-H. pylori IgA antibody is high in our environment. Serum IgA status may be associated with milder degrees of gastritis in our patients but a larger cohort of patients is needed to confirm this. There seems to be a good agreement between serum IgA and CagA statuses among dyspeptic patients.

Immunosuppressive proteins isolated from spiral and coccoid cytoplasmic solutions of Helicobacter pylori

The aim of this study was to investigate the antiproliferative proteins that probably have a role in Helicobacter pylori evade of immune response and cause chronic infection disease and also to see if coccoid form had a role in its chronicity. H. pylori strain VacA s2/m2 positive and CagA negative, from a gastric biopsy of a patient with peptic ulcer disease, was isolated and cultured in brucella agar. Both spiral and coccoid forms were harvested and ruptured by sonication. The cytoplasmic solutions of both forms were collected and their fractions obtained by gel chromatography and preparative polyacrylamide gel electrophoresis. The fractions were analyzed by MTT assay for their antiproliferative activity. We isolated two proteins with a significant dose dependent antiproliferative activity that analyzed with sodium dodecyl sulfate-polyacrylamide gel electrophoresis, one of them that was urease positive showed two bands with 61 and 27 kDa, which is resumed to urease of H. pylori, another consist of 57 and 63 kDa. Helicobacterpylori secret some proteins like urease that inhibit immune cells proliferation response against its antigens.

Development of immunoreagents for diagnostics of CagA-positive Helicobacter pylori infections

BACKGROUND

Helicobacter pylori strains expressing cytotoxic CagA protein are more likely to provoke severe gastric mucosal pathology and cause adenocarcinoma development than that lacking CagA. Determination of the CagA-status of a pathogen, therefore, is regarded as informative approach in H. pylori infection diagnostics and disease risk prediction.

MATERIALS AND METHODS

Molecular cloning, recombinant protein expression in Escherichia coli, affinity chromatography, electrophoresis and commonly used techniques of hybridoma production and screening were used as well as different immunosorbent assays and Western blot procedures.

RESULTS

Four overlapping N-terminally His(6)-tagged recombinant fragments of CagA that covered the entire CagA sequence were produced and purified. An ELISA for specific anti-CagA serum antibodies detection was developed and evaluated. Utilizing recombinant fragments, the first set of monoclonal antibodies against CagA-antigen was produced and characterized. Three antibodies recognized distinct linear epitopes inside conserved regions of the cytotoxin whereas the epitope of the forth antibody was mapped in the variable area of CagA. The monoclonal antibodies allowed discriminating CagA-positive and CagA-negative H. pylori strains by means of Western blot and immunosorbent assays.

CONCLUSIONS

The use of recombinant protein technology allowed obtaining pure CagA antigen, thus providing new perspectives for development of immunodiagnostic reagents. The set of monoclonal antibodies is a valuable tool for determination of CagA-status of H. pylori infection and for the investigation of cytotoxin molecule as well.

Identification of Helicobacter spp. in bile and gallbladder tissue of patients with symptomatic gallbladder disease

BACKGROUND

This experimental study was designed to determine if Helicobacter spp. contribute to benign gallbladder disease using polymerase chain reaction (PCR) methods.

METHODS

Patients with benign gallbladder disease scheduled for elective cholecystectomy at New York University Langone Medical Center were recruited from February to May 2008. Bile, gallbladder tissue and gallstones were collected. DNA was isolated from these specimens and amplified via PCR using C97F and C98R primers specific for Helicobacter spp. Appropriate positive and negative controls were used. Products were analysed with agarose gel electrophoresis, sequenced and results aligned using sequencher. Plasma was collected for detection of anti-Helicobacter pylori antibodies via enzyme-linked immunosorbent assay.

RESULTS

Of 36 patients, 12 patients' bile and/or tissue were positive for Helicobacter spp. by PCR. Species were most homologous with H. pylori, although other Helicobacter spp. were suggested. Six of 12 patients demonstrated anti-Helicobacter antibodies in plasma, suggesting that the remaining six might have demonstrated other species besides H. pylori. Four of six plasma samples with anti-Helicobacter antibodies were anti-CagA (cytotoxin associated gene) negative.

DISCUSSION

Helicobacter spp. can be detected in bile and gallbladder tissue of patients with benign gallbladder disease. The contribution of these bacteria to the pathophysiology of gallbladder disease and gallstone formation requires further study.

Impact ofHelicobacter pyloriInfection 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.

Effects of H pylori infection on gap-junctional intercellular communication and proliferation of gastric epithelial cells in vitro

AIM: To explore the effects of H pylori infection on gap-junctional intercellular communication (GJIC) and proliferation of gastric epithelial cells in vitro.

METHODS: A human gastric epithelial cell line (SGC-7901) cultured on coverslips was exposed overnight to intact H pylori (CagA⁺ or CagA^- strains) and sonicated extracts, respectively. GJIC between the cells was detected by fluorescence redistribution after photobleaching (FRAP) technique. Proliferation of SGC cells was determined by methylthiazolyl tetrazolium (MTT) assay.

RESULTS: When compared with control in which cells were cultured with simple medium alone, both CagA⁺ and CagA^-H pylori isolates could inhibit GJIC (CagA⁺: F = 57.98, P < 0.01; CagA^-: F = 29.59, P < 0.01) and proliferation (CagA⁺: F = 42.65, P < 0.01; CagA^-: F = 58.14, P < 0.01) of SGC-7901 cells. Compared with CagA^- strains, CagA⁺H pylori more significantly down-regulated GJIC of gastric cells (intact H pylori: t = 13.86, P < 0.01; sonicated extracts: t = 11.87, P < 0.01) and inhibited proliferation gastric cells to a lesser extent in vitro (intact H pylori: t = 3.06, P < 0.05; sonicated extracts: t = 3.94, P < 0.01).

CONCLUSION: Compared with CagA^-H pylori strains, CagA⁺ strains down-regulate GJIC of gastric epithelial cells more significantly and inhibit proliferation of gastric cells to a lesser extent in vitro. H pylori, especially CagA⁺ strains, may play an important role in gastric carcinogenesis.

Signaling perturbations induced by invading H. pylori proteins in the host epithelial cells: a mathematical modeling approach

Helicobacter pylori (H. pylori), a gram-negative bacterium, infects the stomach of approximately 50% of the world population. H. pylori infection is a risk factor for developing chronic gastric ulcers and gastric cancer. The bacteria produce two main cytotoxic proteins: Vacuolating cytotoxin A (VacA) and Cytotoxin-Associated gene A (CagA). When these proteins enter the host cell they interfere with the host MAP Kinase and Apoptosis signaling pathways leading to aberrant cell growth and premature apoptosis. The present study expanded existing quantitative models of the MAP Kinase and Apoptosis signaling pathways to take into account the protein interactions across species using the CellDesigner tool. The resulting network contained hundreds of differential equations in which the coefficients for the biochemical rate constants were estimated from previously published studies. The effect of VacA and CagA on the function of this network were simulated by increasing levels of bacterial load. Simulations showed that increasing bacterial load affected the MAP Kinase signaling in a dose dependant manner. The introduction of CagA decreased the activation time of mapK signaling and extended activation indefinitely despite normal cellular activity to deactivate the protein. Introduction of VacA produced a similar response in the apoptosis pathway. Bacterial load activated both pathways even in the absence of external stimulation. Time course of emergence of transcription factors associated with cell division and cell death predicted by our simulation showed close agreement with that determined from a publicly accessible microarray data set of H. pylori infected stomach epithelium. The quantitative model presented in this study lays the foundation for investigating the affects of single nucleotide polymorphisms (SNPs) on the efficiency of drug treatment.

Helicobacter pylori stimulates a mixed adaptive immune response with a strong T-regulatory component in human gastric mucosa

BACKGROUND

Host factors play an important role in the pathophysiology of Helicobacter pylori infection and development of gastritis and related disease. The established opinion is that the T-cell-mediated immune response to H. pylori infection is of Th1 type. Our earlier immune cell phenotype studies indicate a mixed Th1-Th2 profile of the effector cells. Therefore, an extensive adaptive and regulatory cytokine gene expression profile was conducted by quantitative real-time polymerase chain reaction (qPCR).

MATERIALS AND METHODS

Biopsies from gastric mucosa of 91 patients diagnosed as H. pylori negative, H. pylori positive with gastritis, or H. pylori positive with peptic ulcer were obtained by endoscopy. Gene expressions of nine cytokines and CagA status were measured by qPCR.

RESULTS

All cytokine genes showed higher expression levels in the presence of H. pylori when compared to H. pylori-negative samples (fold increase: IL8: x 11.2; IL12A: x 2.4; TNF-alpha: x 5.2; IFN-gamma: x 4.3; IL4: x 3.6; IL6: x 14.7; and IL10: x 6.7). Patients infected with CagA-positive strains had higher expression of IL1-beta and IL18 compared to patients infected with CagA-negative strains (x 1.6 for IL1-beta and x 2.0 for IL18). Patients with duodenal ulcer had a lower antral Th1/Th2 ratio than other H. pylori-positive patients.

CONCLUSIONS

The cytokine profile of H. pylori-infected gastric mucosa shows a mixed Th1-Th2 profile. Furthermore, a high IL10 expression may indicate that also regulatory T cells play a role in the chronic phase of H. pylori infection.

Response of IgG1 and IgG2 subclasses to Helicobacter pylori in subjects with chronic inflammation of the gastric mucosa, atrophy and gastric cancer in a country with high Helicobacter pylori infection prevalence

Polarized immune response to Helicobacter pylori and induction of chronic inflammation may increase the risk of gastric atrophy and adenocarcinoma. We studied the association of the response of IgG1 and IgG2 antibodies to H. pylori with grade of gastric chronic inflammation and atrophy in a population with a high prevalence of H. pylori, and compared these data with the data obtained from the study of gastric cancer patients, as well as with the data for CagA positivity. Altogether, 114 persons from two adult population samples from Estonia and 45 consecutive gastric cancer patients were studied. All patients were positive for the H. pylori antibody determined by ELISA. Adenocarcinoma was classified histologically according to the Laurén's system. The response of the IgG subclasses to H. pylori (acid glycine-extracted whole cell proteins) was determined by ELISA and the results were compared with the ELISA results for the recombinant fragment of the CagA protein. Helicobacter pylori IgG level was lower in atrophic gastritis compared with nonatrophic gastritis (chronic inflammation) (p=0.001). In the group of cancer patients, the response of IgG and IgG1 was lower compared with both gastritis groups (p=0.01 and p=0.0002 for IgG, and p=0.001 and p=0.0005 for IgG1). IgG2 was lower for gastric cancer localized in the corpus (p=0.03). In conclusion, atrophic gastritis and gastric cancer were associated with a significant decline in IgG and IgG1 response to H. pylori compared with nonatrophic gastritis. Higher value of CagA antibodies was seen in gastric cancer and in gastric atrophy compared with nonatrophic gastritis; in gastric cancer patients, IgG1 response to H. pylori was correlated with CagA status.