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Maxime Breban

Publications and source records attributed to Maxime Breban.

At least 19 recordsLinked to original sources
PubMed2006

Characterization and functional consequences of underexpression of clusterin in rheumatoid arthritis.

We previously compared by microarray analysis gene expression in rheumatoid arthritis (RA) and osteoarthritis (OA) tissues. Among the set of genes identified as a molecular signature of RA, clusterin (clu) was one of the most differentially expressed. In the present study we sought to assess the expression and the role of CLU (mRNA and protein) in the affected joints and in cultured fibroblast-like synoviocytes (FLS) and to determine its functional role. Quantitative RT-PCR, Northern blot, in situ hybridization, immunohistochemistry, and Western blot were used to specify and quantify the expression of CLU in ex vivo synovial tissue. In synovial tissue, the protein was predominantly expressed by synoviocytes and it was detected in synovial fluids. Both full-length and spliced isoform CLU mRNA levels of expression were lower in RA tissues compared with OA and healthy synovium. In synovium and in cultured FLS, the overexpression of CLU concerned all protein isoforms in OA whereas in RA, the intracellular forms of the protein were barely detectable. Transgenic overexpression of CLU in RA FLS promoted apoptosis within 24 h. We observed that CLU knockdown with small interfering RNA promoted IL-6 and IL-8 production. CLU interacted with phosphorylated IkappaBalpha. Differential expression of CLU by OA and RA FLS appeared to be an intrinsic property of the cells. Expression of intracellular isoforms of CLU is differentially regulated between OA and RA. We propose that in RA joints, high levels of extracellular CLU and low expression of intracellular CLU may enhance NF-kappaB activation and survival of the synoviocytes.

Arthritis, Rheumatoid↗
PubMed2006

TNFalpha antagonist therapy in ankylosing spondylitis and psoriatic arthritis: recommendations of the French Society for Rheumatology.

OBJECTIVES: To develop recommendations for TNFalpha antagonist therapy in patients with spondyloarthropathies. METHODS: The Delphi consensus procedure was used to select questions, to which evidence-based answers were sought in the literature. Expert opinion was used when needed to estimate the risks and benefits of TNFalpha antagonists. TNFalpha antagonists exert potent antiinflammatory effects but fail to provide a definitive cure. RESULTS: Recommendations were developed for patients with ankylosing spondylitis (AS) or psoriatic arthritis (PsA). The following criteria for TNFalpha antagonist therapy were selected: definitive diagnosis of AS or PsA, active disease for at least 4 consecutive weeks documented during two physician visits, overall physician's assessment of disease activity>/=4/10 and BASDAI>/=4/10 in axial disease or at least three tender and swollen joints in peripheral disease, failure to respond adequately to at least three nonsteroidal antiinflammatory drugs given in optimal dosages for at least 3 months in axial disease or at least one disease-modifying antirheumatic drug (methotrexate, leflunomide, sulfasalazine) for at least 4 months, with local glucocorticoid injections if appropriate, in peripheral disease. Effectiveness and safety should be evaluated by a rheumatologist. The frequency of monitoring depends on the drug. Lack of effectiveness should be defined as inadequate improvement after 6-12 weeks, with a less than two-point decrease in the BASDAI in axial disease or a less than 30% decrease in the tender and swollen joint counts in peripheral disease. CONCLUSION: These clinical practice recommendations should help rheumatologists in their everyday decisions regarding the use of TNFalpha antagonist therapy in patients with AS or PsA.

Anti-Inflammatory Agents↗
PubMed2006

The genetics of spondyloarthropathies.

The spondyloarthropathies constitute a group of inflammatory joint diseases linked by shared characteristics that include a strong common genetic background. Genetic factors include major histocompatibility complex (MHC) genes, among which HLA-B27 contributes 30% of the overall genetic susceptibility to spondyloarthropathies, and non-MHC genes, none of which have been identified to date. Genome screens have identified regions that may contain susceptibility genes for spondyloarthropathies. In particular, a locus on the long arm of chromosome 9 (9q31-34) was identified by two groups working independently from each other. Studies using the candidate gene approach ruled out a role for most of the tested genes, including CARD15/NOD2. However, several independent groups have reported significant associations between ankylosing spondylitis and the IL-1 gene cluster on the long arm of chromosome 2.

Genetic Predisposition to Disease↗
PubMed2006

Genetics of spondyloarthritis.

This chapter reviews evidence from family and twin studies supporting the strong genetic predisposition of the spondyloarthritides (SpA), which is only partially attributable to the major histocompatibility locus. The current concept of SpA heterogeneity has been challenged by family studies which showed that all articular and extra-articular manifestations were linked together, and most likely to the same genetic factors.

Animals↗
PubMed2006

Inhibition of anti-tuberculosis T-lymphocyte function with tumour necrosis factor antagonists.

Reactivation of latent Mycobacterium tuberculosis (Mtb) infection is a major complication of anti-tumour necrosis factor (TNF)-alpha treatment, but its mechanism is not fully understood. We evaluated the effect of the TNF antagonists infliximab (Ifx), adalimumab (Ada) and etanercept (Eta) on anti-mycobacterial immune responses in two conditions: with ex vivo studies from patients treated with TNF antagonists and with the in vitro addition of TNF antagonists to cells stimulated with mycobacterial antigens. In both cases, we analysed the response of CD4+ T lymphocytes to purified protein derivative (PPD) and to culture filtrate protein (CFP)-10, an antigen restricted to Mtb. The tests performed were lymphoproliferation and immediate production of interferon (IFN)-gamma. In the 68 patients with inflammatory diseases (rheumatoid arthritis, spondylarthropathy or Crohn's disease), including 31 patients with a previous or latent tuberculosis (TB), 14 weeks of anti-TNF-alpha treatment had no effect on the proliferation of CD4+ T lymphocytes. In contrast, the number of IFN-gamma-releasing CD4+ T lymphocytes decreased for PPD (p < 0.005) and CFP-10 (p < 0.01) in patients with previous TB and for PPD (p < 0.05) in other patients (all vaccinated with Bacille Calmette-Guérin). Treatments with Ifx and with Eta affected IFN-gamma release to a similar extent. In vitro addition of TNF antagonists to CD4+ T lymphocytes stimulated with mycobacterial antigens inhibited their proliferation and their expression of membrane-bound TNF (mTNF). These effects occurred late in cultures, suggesting a direct effect of TNF antagonists on activated mTNF+ CD4+ T lymphocytes, and Ifx and Ada were more efficient than Eta. Therefore, TNF antagonists have a dual action on anti-mycobacterial CD4+ T lymphocytes. Administered in vivo, they decrease the frequency of the subpopulation of memory CD4+ T lymphocytes rapidly releasing IFN-gamma upon challenge with mycobacterial antigens. Added in vitro, they inhibit the activation of CD4+ T lymphocytes by mycobacterial antigens. Such a dual effect may explain the increased incidence of TB in patients treated with TNF antagonists as well as possible differences between TNF antagonists for the incidence and the clinical presentation of TB reactivation.

Adalimumab↗
PubMed2005

Animal models of HLA-B27-associated diseases: new outcomes.

The HLA-B27 molecule is strongly associated with the spondyloarthropathies, a group of chronic inflammatory diseases, affecting the skeleton, the bowel and the skin. This association has been largely studied, but mechanisms of pathology remain unclear. The HLA-B27 transgenic rats develop a spontaneous disease that strikingly resembles human spondyloarthropathies, dependent of bacterial flora and implicating the immune system. The presence of CD4+ T cells is required, and antigen presenting cells (APC) expressing high levels of HLA-B27 likely play an important role. Indeed, APC are defective in naive T lymphocytes stimulation. This default appears to implicate the APC/T cells contact, and may result in a loss of tolerance toward microbial flora. Two models of skeletal inflammation linked to HLA-B27 have been developed in mice. The ANKENT mice develop a spontaneous ossifying enthesitis affecting ankle and tarsal joints, with increased frequency in the presence of an HLA-B27 transgene. The HLA-B27 transgenic mice lacking endogenous beta2 microglobulin develop arthritis of hind-paws. In this model, homodimers of B27 heavy chains could be implicated in the pathogenesis by presenting exogenous peptides to CD4+ T cells.

Animals↗
PubMed2005

Two major spondylarthropathy phenotypes are distinguished by pattern analysis in multiplex families.

OBJECTIVE: To examine whether spondylarthropathy (SpA) disease manifestations would combine in any ordered pattern among patients from SpA multiplex families. METHODS: SpA patients (n = 540) belonging to 190 multiplex families were thoroughly investigated. Clinical data was collected, systematic pelvic radiographs were taken, and HLA-B27 status was determined. The patterns of SpA manifestations were examined by several methods, including multiple correspondence analysis, nonhierarchical and hierarchical clustering, and discriminant analysis. RESULTS: The nonhierarchical cluster analysis allowed us to classify patients, independent of disease duration, into 2 major groups of comparable size. Group A contained a majority of the women, whereas group B predominantly consisted of men. The 2 groups were very similar regarding axial symptoms, radiographic sacroiliitis, and uveitis. Group B was characterized by a younger age at onset and a higher frequency of clinical enthesitis, peripheral arthritis, dactylitis, psoriasis, and inflammatory bowel disease than group A. Patients belonging to those groups exhibited some degree of familial aggregation, thereby supporting their intrinsic validity. CONCLUSION: Pattern analysis of SpA manifestations among familial SpA allowed us to recognize 2 main clusters independent of disease duration. Furthermore, there was a trend toward aggregation by cluster among families, suggesting that they are determined by specific genetic factors. These clusters may indeed correspond to different severity patterns.

Adolescent↗
PubMed2005

Impact of ultrasound imaging on local corticosteroid injections of symptomatic ankle, hind-, and mid-foot in chronic inflammatory diseases.

OBJECTIVE: To assess the impact of ultrasonography (US) on local corticosteroid (CS) injections of painful ankle, hindfoot, and midfoot in chronic inflammatory diseases. METHODS: Consecutive patients with chronic rheumatic diseases admitted to the hospital for local CS injections of painful ankle, hindfoot, or midfoot were enrolled in this study. Clinical and radiographic evaluation was performed by the physician in charge of CS injections, and US examination was performed by an independent examiner blinded to the clinical and radiologic findings. According to a randomized weekly-periods design, the physician planned CS injections either aware (G1 group) or unaware (G2 group) of US results. In the latter case, he was nonetheless informed of US results after he had performed the injections. Impact of this information on the treatment planning was assessed in all cases. Prognostic impact of US was also evaluated by comparing the change in global assessment of efficacy of CS injections, in activity of the disease, and in the Western Ontario and McMaster Universities (WOMAC) subscales after 1 and 3 months, between G1 and G2 groups. RESULTS: The knowledge of US findings led the physician to change his decision of local CS injections in 56 (82%) of 68 patients studied. Among 1,131 assessed sites, by clinical, radiographic, and US evaluation, injection was cancelled in 37 (15%) of 242 proposed sites, whereas it was decided in 74 (8%) additional sites. After 1 month, there was an improvement in G1 as compared with G2 groups. The mean +/- SD change in WOMAC physical function subscale was 15.6 +/- 17.5 in G1 versus 8 +/- 13 in G2 (P = 0.0305). After 3 months, only the global assessment of efficacy of CS injections was statistically greater in G1 than in G2 group (P = 0.0170). CONCLUSION: US frequently led the physician to change his diagnosis of inflammatory lesions in painful foot, and consequently his planning of CS injections. Moreover, US could improve the response to local treatment.

Arthritis, Rheumatoid↗
PubMed2004

Significant linkage to spondyloarthropathy on 9q31-34.

Spondyloarthropathy (SpA) is a frequent rheumatologic disorder with a prevalence of 0.3% in Caucasian populations from western Europe. It commonly presents as chronic axial and/or peripheral arthritis with potential disabling outcome. SpA is also variably associated with extra-articular manifestations. The pathogenesis of SpA is considered as complex, with a strong genetic component. Human leukocyte antigen B27 has been identified as a predisposing factor for SpA, but family and twin studies suggest that additional genetic risk factors exist outside the major histocompatibility complex (MHC). To map SpA susceptibility loci, 120 multiplex SpA families were included in a genome-wide scan. Linkage analyses performed on the first 65 families allowed us to identify four candidate non-MHC regions on chromosomes 5q, 9q, 13q and 17q, which were further explored in the remaining 55 multiplex families (extension study). Non-parametric multipoint linkage analyses of the whole data set yielded evidence of significant linkage to 9q31-34, in the vicinity of marker D9S1776 (NPL=4.87, LOD=5.15, P=0.00002). This result provides evidence for the presence of a non-MHC susceptibility locus for SpA mapping to 9q31-34.

Chromosome Mapping↗
PubMed2004

HLA-B27 heavy chain homodimers are expressed in HLA-B27 transgenic rodent models of spondyloarthritis and are ligands for paired Ig-like receptors.

HLA-B27 transgenic rats and strains of HLA-B27-transgenic beta(2)-microglobulin (beta(2)m)-deficient mice develop a multisystem inflammatory disease affecting the joints, skin, and bowel with strong similarity to human spondyloarthritis. We show that HLA-B27 transgenic mice and rats express HC10-reactive, beta(2)m-free HLA-B27 homodimers (B27(2)) and multimers, both intracellularly and at the cell surface of leukocytes, including rat dendritic cells. Fluorescent-labeled tetrameric complexes of HLA-B27 homodimers (B27(2) tetramers) bind to populations of lymphocytes, monocytes, and dendritic cells. The murine (and probably rat) paired Ig-like receptors (PIRs) are ligands for B27(2). Thus, B27(2) tetramers stain RBL cells transfected with murine activating PIR-A4 and inhibitory PIR-B receptors. Murine PIR-A and -B can be immunoprecipitated from the RAW264.7 macrophage cell line, and murine PIR-A can be immunoprecipitated from the J774.A1 line using B27(2). B27(2) tetramer staining corresponds to the distribution of PIR expression on lymphoid and myeloid cells and on murine macrophage cell lines. B27(2) can induce TNF-alpha release from the J774.A1 macrophage cell line. The binding of B27(2) to PIR is inhibited by HC10, an mAb that ameliorates arthritis in HLA-B27(+) beta(2)m(-/-) mice. The expression and PIR recognition of B27(2) could explain the pathogenesis of rodent spondyloarthritis.

Animals↗
PubMed2004

Defective costimulatory function is a striking feature of antigen-presenting cells in an HLA-B27-transgenic rat model of spondylarthropathy.

OBJECTIVE: A disease resembling the human spondylarthropathies develops in HLA-B27-transgenic rats. This disease in rats is mediated by CD4+ T cells, but antigen-presenting cells (APCs) may also play a role. Dendritic cells (DCs) have been reported to be defective in allogeneic mixed lymphocyte culture in this model. Here, we further investigated the functional defect of APCs. METHODS: DCs and B cells from nontransgenic, HLA-B27 (33-3)-transgenic, and HLA-B7 (120-4)-transgenic rats were used to stimulate T cells. Surface expression of HLA-B transgene and rat molecules on APCs and the formation of conjugates between DCs and T cells were monitored by flow cytometry. RESULTS: We observed a strikingly defective stimulation of allogeneic and syngeneic T lymphocytes by APCs from HLA-B27 but not HLA-B7 rats, even if stimulation was driven in the presence of anti-T cell receptor (TCR) antibody. We found no evidence that HLA-B27 DCs were immature, lacked production of some diffusible factor, or produced an inhibitory factor for T cells. When comparing the levels of expression of class II major histocompatibility complex, CD2, intercellular adhesion molecule 1, lymphocyte function-associated antigen 1, B7, and CD40 molecules at the surface of DCs from 33-3, 120-4, and nontransgenic rats, we found little difference. However, HLA-B27-transgenic DCs formed fewer conjugates with T cells than did nontransgenic DCs. Furthermore, the proportion of conjugates formed between DCs and T cells, as well as the difference between nontransgenic and HLA-B27-transgenic DCs, were in large part reduced by blocking CD86 on DCs. CONCLUSION: We confirmed defective stimulation of T cells by APCs in HLA-B27 rats, the mechanism of which appears to implicate APC/T cell contact, independent of TCR engagement. In addition, decreased use of the CD86 costimulatory molecule by B27 DCs was observed. Impaired costimulatory function could result in a loss of tolerance toward microbial flora in this model.

Animals↗
PubMed2004

Ophthalmic findings and frequency of extraocular manifestations in patients with HLA-B27 uveitis: a study of 175 cases.

OBJECTIVE: To analyze ocular and extraocular manifestations in patients with HLA-B27-associated uveitis. DESIGN: Large, observational case series. PARTICIPANTS: One hundred seventy-five consecutive patients with HLA-B27-associated uveitis seen in a single center between January 1996 and March 2001. METHODS: Features of uveitis were noted and patients were referred systematically to rheumatologists. The history of previous uveitis attacks and extraocular manifestations of spondyloarthropathy was recorded. Assessments of spondyloarthropathies were based on criteria established by the European Spondyloarthropathy Study. MAIN OUTCOME MEASURES: Percentage of patients with extraocular manifestations. The time between the first episode of uveitis and symptoms or diagnosis of extraocular disease was estimated. Characteristics of uveitis were analyzed. RESULTS: The male-to-female ratio was 1.3 to 1, and the median age at the time of the first attack of uveitis was 31 years. An HLA-B27-associated extraocular disorder was seen in 136 cases (77.7%). Of these, ankylosing spondylitis was diagnosed in 81 patients (46.3%) and presumed in 17 (9.7%). Undifferentiated spondyloarthropathy was observed in 21 patients (12%) and other HLA-B27-associated diseases in 17 patients (9.7%). The onset of extraocular symptoms occurred at a younger age (mean+/-standard deviation [SD], 26.4+/-11.1 years) than the first attack of uveitis (mean+/-SD, 34.0+/-14.1 years; P<0.0001). The diagnosis of an extraocular disease was made only after the appearance of ophthalmic manifestations in 88 of 136 patients. Among 117 patients (66.9%) with more than 1 episode of uveitis, same eye attacks were observed in 48 of 117 patients (41.0%), more than the expected percentage than attacks of a random eye (P<0.0001). The median +/- SD frequency of active episodes of uveitis was 0.8+/-0.6 per year and decreased as the duration of the disease lengthened (P<0.0001). Patients with extraocular disease had a greater total number of attacks of uveitis (P = 0.02), but other ophthalmic findings did not differ between patients with and without an extraocular disorder. CONCLUSIONS: Uveitis is frequently the first indication of a previously undiagnosed HLA-B27-associated extraocular disease. The most common of these diseases are spondyloarthropathies.

Acute Disease↗
PubMed2004

Animal models of HLA-B27-associated diseases.

The HLA-B27 molecule is strongly associated with the spondyloarthropathies (SpA), a group of inflammatory conditions affecting the skeleton, the skin and several mucosae. The mechanism of this association remains unknown, largely because the HLA-B27 molecule displays normal function. A disease that closely mimicks SpA arises spontaneously in HLA-B27 transgenic rats. This disease is dependent on the presence of a normal bacterial flora and implicates the immune system. The presence of both CD4+ T cells and antigen presenting cells (APCs) expressing high levels of HLA-B27, seems of critical importance in its pathogenesis, whereas CD8+ T cells are dispensable. The T cell stimulatory function of APCs is disturbed by the HLA-B27 molecule. This disease could result from a failure of tolerance, related in part to high level of B27 expression in professional APCs and to the immune response to gut bacteria. In contrast, HLA-B27 transgenic mice have usually remained healthy. However, two types of inflammatory conditions affecting the skeleton, which arise in mice of susceptible background after exposure to a conventional bacterial flora, are increased by an HLA-B27 transgene. The first is ANKENT, a spontaneous ankylosing enthesitis that affects ankle and/or tarsal joints of ageing mice; the second is a spontaneous arthritis of hindpaws developing in mice lacking endogenous mbeta2m. As in rats, the absence of CD8+ T cells in the latter model, argues against the "arthritogenic peptide" hypothesis. In these mbeta2m0 mice, B27 free heavy chain could be implicated in the pathogenesis of arthritis by presenting extracellular peptides to CD4+ T cells.

Alleles↗
PubMed2003

[Therapeutic use of anti-TNF-alpha agents in spondyloarthropathies].

CLASSICAL DATA: Spondyloarthropathies regroup several rheumatological entities (ankylosing spondylitis, reactive arthritis, psoriatic rheumatism, entero-colopathic disease rheumatism, undifferentiated spondyloarthropathies ) with validated diagnosis criteria. Drug therapy is based upon NSAIDs (non-steroidal antiinflammatories). Refractory forms may lead to severe functional impairment, raising the need of more effective treatments. IN FAVOUR OF ANTI-TNF-ALPHA AGENTS: Several arguments (TNF-alpha serum levels, elevated levels of mRNA, TNF messengers, in sacro iliac biopsies, efficacy of anti TNF-alpha agents in Crohn's disease ) justify the use of anti-TNF-alpha agents in the treatment of spondyloarthropathies. Two biologic agents have been assessed in these circumstances: a monoclonal antibody (Infliximab) and a soluble form of the TNF receptor (Etanercept). EFFICACY AND SAFETY: Results of open and controlled studies, although on small series, demonstrated the significant efficacy of anti-TNF-alpha agents on the various clinical, biological, functional and quality of life parameters, and confirmed by imaging (MRI ). Tolerance is fair, but two cases of diffuse tuberculosis have been reported with Infliximab. THERAPEUTIC PROGRESS: Even if additional studies are required to answer some questions (long term efficacy and safety, treatment modalities), anti TNF agents appear as a therapeutic progress in refractory spondyloarthropathies, for which few validated options have existed up till now.

Antibodies, Monoclonal↗
PubMed2003

Assessment of peripheral enthesitis in the spondylarthropathies by ultrasonography combined with power Doppler: a cross-sectional study.

OBJECTIVE: To assess the prevalence and severity of peripheral enthesitis among the different subtypes of spondylarthropathy (SpA) by using ultrasonography (US) in B mode with power Doppler. METHODS: One hundred sixty-four consecutive patients with SpA (according to the criteria of the European Spondylarthropathy Study Group) and 64 control patients (34 with mechanical low back pain [MBP] and 30 with rheumatoid arthritis [RA]) underwent US examination of major entheses of their limbs. Particular attention was given to the detection of vascularization at the following sites: cortical bone insertion of entheses, junction between tendon and entheses, body of tendon, and bursa. RESULTS: Abnormal US findings consistent with at least one enthesitis were observed in 161 of 164 SpA patients (98%), affecting 1,131 of 2,952 entheses examined (38%). In contrast, only 132 of 1,152 entheses (11%) were found to be abnormal in 33 of 64 control patients (52%). US enthesitis was most commonly distributed in the distal portion of the lower limbs, irrespective of SpA subtype and of skeletal distribution of clinical symptoms. None of the abnormal entheses in control patients showed vascularization, compared with 916 of 1,131 abnormal entheses in SpA patients (81%), where it was always detected at the cortical bone insertion and sometimes also in the bursa. In SpA patients, the US pattern depended on the clinical presentation, with a higher prevalence of the most severe stages in those with peripheral forms. CONCLUSION: US in B mode combined with power Doppler allowed the detection of peripheral enthesitis in a majority of SpA patients, but not in MBP or RA patients. The presence of entheseal involvement was independent of SpA subtype, but its degree of severity appeared to be greater in peripheral forms. US could be very useful for both the diagnosis and the assessment of SpA activity.

Adult↗
PubMed2003

Familial and genetic aspects of spondyloarthropathy.

Predisposition to SpA is largely determined by genetic factors including HLA-B27 and other as yet unknown genes that might be tracked by a positional cloning approach. Analysis performed on a large cohort of SpA multiplex families revealed that the different articular and extra-articular inflammatory manifestations comprising the SpA spectrum were linked together, implying that they were determined by a shared set of factors, including HLA-B27. The variety of phenotypes appeared to be related to ubiquitous and secondary factors. Hence, SpA appeared to be more homogenous than previously thought and should be regarded as a unique disease. This conclusion also implies that genetic studies should be performed on the whole group. Such an approach allowed identification of HLA-DR4 as a gene contributing to SpA predisposition independently of linkage disequilibrium with HLA-B27. A significant role for CARD15/NOD2 gene in predisposition to SpA was ruled out, in agreement with the hypothesis that the inflammatory bowel disease in SpA is determined by factors different than those responsible for isolated Crohn's disease.

Family Health↗
PubMed2003

[What are the gastric modifications induced by acute and chronic Helicobacter pylori infection?].

H. pylori colonisation of the stomach causes the recruitment of the inflammatory cells by the adherence of the bacteria with the epithelium and the release of factors of virulence either to the contact (oipA or other soluble factors) or in the cell by translocation (CagA). Such contact triggers interleukin 8 expression in the epithelial cell and attracts lymphocytes and monocytes into the chorion. Bacterial lipopolysaccharide and urease support the activation of these inflammatory cells. The lymphocytes produce pro-inflammatory cytokines, which direct the immune response towards the Th1 pathway. The variability of the inflammatory response depends on hereditary factors of the host such as the interleukin 1 genotypes, which determine the level of the pro-inflammatory cytokine expression, and of bacterial factors such as the cag pathogenicity island, the lipopolysaccharide and the vacuolating toxin, vacA. The mucosal inflammation provokes apoptosis and atrophy of the epithelial cells through the effect of pro-inflammatory cytokines and free radicals. Epithelial proliferation is a consequence of excessive apoptosis caused by the infection. It is stimulated by the expression of inducible cyclo-oxygenase and inducible nitric oxide synthase. The development of atrophic gastritis towards cancer is supported by nitric oxide which has a mutagenic effect on DNA and inhibits p53 protein and by the bacterium itself which decreases DNA mismatch repairing activity. The gastritis induced by Helicobacter pylori changes acid secretion according to the prevalent location of the gastritis in the antrum or in the gastric body. Prevalent gastritis in the gastric body causes hypochlorhydria by reducing the release of histamin from ECL cells and inhibiting the parietal cells through the effect of tumor necrosis factor and interleukin 1-beta. Hypochlorhydria is more marked among patients having a pro-inflammatory genotype for interleukin 1-beta and those infected by bacteria with virulence factors. In the event of antrum predominant gastritis, the pro-inflammatory cytokines cause a reduction of somatostatin and gastrin releases from the D and the G cells, respectively. The result of all is increased maximal acid output and the meal-stimulated acid secretion.

Apoptosis↗