CD4+ regulatory T cells in gastric cancer mucosa are proliferating and express high levels of IL-10 but little TGF-ß.

BACKGROUND: An increase of regulatory T cells, defined as CD25high- and/or FOXP3+-expressing CD4+ T cells, within tumors has been reported in several studies. Tregs promote tumor growth by modulating the antitumor immune response, mainly through inhibition of T-cell-mediated tumor cell killing: this has been suggested to be dependent on IL-10 and/or TGF-ß. In stomach cancer, the mechanisms behind the accumulation of Tregs in tumor tissue has not been fully elucidated, and neither has Treg gene expression in situ. MATERIALS AND METHODS: Stomach tissue from gastric cancer patients undergoing gastric resection was analyzed using flow cytometry and cell sorting, followed by RT-PCR. RESULTS: We observed that stomach CD4+ FOXP3+ T cells proliferated to a higher degree than CD4+ FOXP3- T cells, which may contribute to Treg accumulation in the mucosa. By analyzing DNA methylation, we demonstrated that both proliferating and nonproliferating FOXP3+ T cells exhibited complete demethylation of the FOXP3 gene, indicating a stable FOXP3 expression in both cell populations. Furthermore, analysis of T-cell populations isolated directly from the tumor and tumor-free mucosa demonstrated that CD4+ CD25high T cells have a higher IL-10/IFN-γ gene expression ratio but express lower levels of TGF-ß than CD4+ CD25low/- T cells. CONCLUSION: We demonstrate strong proliferation among regulatory CD4+ FOXP3+ CD25high T cells in the gastric cancer mucosa. These local Treg express a suppressive cytokine profile characterized by high IL-10 and low TGF-ß and IFN-γ production.

Immune responses against Helicobacter pylori in gastric cancer patients and in risk groups for gastric cancer.

BACKGROUND: It has previously been reported that weak serum IgG but elevated IgA antibody responses against H. pylori may be associated with risk of gastric cancer (GC) development. To search for potential immunologic markers for GC, we analyzed antibody responses against H. pylori in risk groups of cancer development. MATERIAL AND METHODS: Sera and stomach biopsies collected from H. pylori-infected GC patients as well as from patients with gastric ulcer (GU), atrophic gastritis, intestinal metaplasia (IM) and duodenal ulcer and from H. pylori-infected control subjects without atrophy or IM, and in addition from H. pylori-negative subjects were analyzed for IgG and IgA antibodies against three different H. pylori antigen preparations, that is, membrane protein (MP), urease, and CagA. RESULTS: We observed an increased serum IgA/IgG titer ratio against H. pylori anti-MP in GC and GU patients, and against CagA in Hp-infected GC patients and risk groups. Female patients with GC had a higher serum anti-MP IgA/IgG titer ratio and a higher proportion of poorly differentiated cancer compared with male patients. As earlier observed, the non-tumorous mucosa of H. pylori-infected GC patients contained considerably lower levels of total IgA and H. pylori-specific IgA compared with H. pylori-infected controls. Similarly, we observed decreased specific mucosal anti-MP IgA response in patients with IM. CONCLUSION: We observed several differences in local and systemic immunologic responses against H. pylori in H. pylori-infected GC patients and putative GC risk group patients compared with H. pylori-infected controls. These findings may be of importance in efforts to identify risk groups of GC or early stages of GC.

FOXP3-expressing CD4(+) T-cell numbers increase in areas of duodenal gastric metaplasia and are associated to CD4(+) T-cell aggregates in the duodenum of Helicobacter pylori-infected duodenal ulcer patients.

BACKGROUND: We have previously demonstrated that Helicobacter pylori infection is associated with an increased number of CD4(+)CD25(high) regulatory T cells in the gastric and duodenal mucosa. In this study, we determined the number and localization of CD4(+) cells expressing the regulatory T-cell-specific transcription factor FOXP3 in the antrum and duodenum of duodenal ulcer patients, asymptomatic carriers, and uninfected individuals. We also determined gene expression levels of FOXP3 as well as anti- and proinflammatory cytokines before and after H. pylori eradication. METHODS: Cellular FOXP3 expression was studied by immunofluorescence and flow cytometry, and transcription levels of FOXP3, interleukin (IL)-10, transforming growth factor-beta, CD4, and interferon-gamma were analyzed by real-time reverse transcription-polymerase chain reaction. RESULTS: We found an increased (6-fold) frequency of CD4(+)FOXP3(+) T cells in H. pylori-infected gastric mucosa; interestingly 26% of these cells did not co-express CD25. The increase of FOXP3-expressing T cells in the antrum of infected individuals was dependent on the presence of H. pylori, since eradication therapy resulted in 4-fold lower levels of FOXP3 and IL-10 mRNA in the antrum. Furthermore, higher numbers of CD4(+)FOXP3(+) T cells were found in areas of duodenal gastric metaplasia in the duodenum of duodenal ulcer patients compared to duodenal gastric metaplasia of asymptomatic individuals and healthy mucosa in both patient groups. In duodenal ulcer patients, the CD4(+)FOXP3(+) T cells were more highly associated to aggregates in the duodenal mucosa. CONCLUSION: The numbers of CD4(+)FOXP3(+) T cells are increased and localized in CD4(+) T-cell aggregates in areas of duodenal gastric metaplasia in duodenal ulcer patients.

Interleukin 1-beta gene polymorphisms and risk of gastric cancer in Sweden.

OBJECTIVE: Helicobacter pylori (H. pylori) infection stimulates the production of interleukin (IL)-1 beta, a pro-inflammatory cytokine and suppressor of gastric acid secretion. As both inflammation and hypochlorhydria, which might facilitate proximal colonization of H. pylori and other bacterial species alike, have been implicated in gastric carcinogenesis, much attention has been directed to functional genetic polymorphisms that affect the production of IL-1 beta. The purpose of this study was to clarify the role of these polymorphisms. MATERIAL AND METHODS: We analysed a population-based, case-control study in 5 Swedish counties and a hospital-based, case-control study conducted in 8 Swedish hospitals, with a total of 351 gastric cancer cases and 539 controls. The IL1B-31, IL1B-511 and IL1B+3954 biallelic polymorphisms were genotyped using pyrosequencing. The variable number of tandem repeats (VNTR) polymorphism of IL1-RN was analysed using polymerase chain reaction (PCR) followed by gel electrophoresis. Relative risks were estimated by odds ratios with 95% confidence intervals, derived from unconditional logistic regression. RESULTS: The risk of gastric cancer was unrelated to genotype in all of the studied polymorphic loci, and the absence of any association was confirmed in both the population-based and hospital-based case-control studies. Analyses confined to histological subtypes (intestinal or diffuse) and site-specific tumours (cardia or distal stomach), as well as analyses stratified by H. pylori infection status and family history of gastric cancer, did not reveal any significant increases or decreases in risk. CONCLUSION: Our results do not lend support to the hypothesis that human genetic polymorphisms related to the production of IL-1 beta are associated with the risk of gastric cancer.

CCL28 is increased in human Helicobacter pylori-induced gastritis and mediates recruitment of gastric immunoglobulin A-secreting cells.

Human Helicobacter pylori infection gives rise to an active chronic gastritis and is a major risk factor for the development of duodenal ulcer disease and gastric adenocarcinoma. The infection is accompanied by a large accumulation of immunoglobulin A (IgA)-secreting cells in the gastric mucosa, and following mucosal immunization only H. pylori-infected volunteers mounted a B-cell response in the gastric mucosa. To identify the signals for recruitment of gastric IgA-secreting cells, we investigated the gastric production of CCL28 (mucosa-associated epithelial chemokine) and CCL25 (thymus-expressed chemokine) in H. pylori-infected and uninfected individuals and the potential of gastric B-cell populations to migrate toward these chemokines. Gastric tissue from H. pylori-infected individuals contained significantly more CCL28 protein and mRNA than that from uninfected individuals, while CCL25 levels remained unchanged. Chemokine-induced migration of gastric lamina propria lymphocytes isolated from patients undergoing gastric resection was then assessed using the Transwell system. IgA-secreting cells and IgA(+) memory B cells from H. pylori-infected tissues migrated toward CCL28 but not CCL25, while the corresponding cells from uninfected patients did not. Furthermore, IgG-secreting cells from H. pylori-infected patients did not migrate to CCL28 but instead to CXCL12 (SDF-1alpha). However, chemokine receptor expression did not correlate to the migratory pattern of the different B-cell populations. These studies are the first to show increased CCL28 production during gastrointestinal infection in humans and provide an explanation for the large influx of IgA-secreting cells to the gastric mucosa in H. pylori-infected individuals.

Impact of clinical experience and diagnostic performance in patients with acute abdominal pain.

Background. The aims were to evaluate the importance of the formal competence of the emergency department physician, the patient's time of arrival at the emergency department, and the use of a structured schedule for investigation of patients with acute abdominal pain. Methods. Patients attending the Mora Hospital with acute abdominal pain from 1997 to 2000 were registered prospectively according to a structured schedule. Registration included history, symptoms, signs, preliminary diagnosis, surgery and final diagnosis after at least one year. Results. 3073 acute abdominal pain patients were included. The preliminary diagnosis, as compared with the final diagnosis, was correct in 54% (n = 1659). Previously, during 1996, a base-line registration of 790 patients had a 58% correct diagnoses (n = 458). A majority of the patients (n = 2699; 88%) were managed by nonspecialists. The proportion of correct diagnoses was 54% (n = 759) for pre-registrar house officers and 55% (n = 443) for senior house officers. Diagnostic performance at the emergency department was independent of patient's time of arrival. Conclusions. A structured schedule for investigation did not improve the diagnostic precision at the emergency department in patients with acute abdominal pain. The diagnostic performance was independent of the formal competence of the physician and the patient's time of arrival.

Diagnostic pitfalls and accuracy of diagnosis in acute abdominal pain.

OBJECTIVE: To identify the differential diagnostic difficulties in acute abdominal pain at the emergency department and during hospitalization. MATERIAL AND METHODS: Patients with abdominal pain lasting for up to 7 days were registered during 1997-2000 and re-evaluated one year after discharge (n=2851). RESULTS: Diagnoses with low sensitivity at the emergency department but markedly increased sensitivity at discharge were non-specific abdominal pain with a sensitivity value at the emergency department of 0.43, appendicitis 0.80, gallstones 0.68, constipation 0.74 and peptic ulcer 0.26. Corresponding kappa-values were 0.48, 0.74, 0.84, 0.88 and 0.93, respectively. Malignancy, gynaecological complaints, dyspepsia, urinary tract infection and diverticulitis displayed fairly good concordance between the preliminary and discharge judgements, but the predictive diagnostic value was still low at discharge. Sensitivity values at discharge were 0.40, 0.75, 0.73, 0.77 and 0.83, respectively. Among 479 surgically treated patients, 104 initially received a diagnosis usually not requiring surgery and had a median delay until operation of 22 h (95% CI 30-50 h), compared with 8 h (12-18 h) for referrals. CONCLUSIONS: Non-specific abdominal pain is the main differential diagnostic problem in the emergency department also for diagnoses requiring surgery. Constipation is a diagnostic pitfall and when making this diagnosis a careful re-evaluation is necessary.

Is the association between Helicobacter pylori and gastric cancer confined to CagA-positive strains?

BACKGROUND: Infection with Helicobacter pylori is associated with an increased risk of gastric cancer. Several studies have indicated that the association differs with strain type. We aimed to find out if infection with strains lacking the virulence factor CagA is linked to gastric cancer risk. MATERIALS AND METHODS: In a hospital-based case-control study, we collected sera from 100 case patients with a newly diagnosed gastric adenocarcinoma and 96 control patients with diseases unrelated to H. pylori status. Antibodies to H. pylori were analyzed by enzyme-linked immunosorbent assay (ELISA), and antibodies to CagA were detected by immunoblot. Logistic regression was used to obtain odds ratios (ORs) as estimates of relative risk, adjusted for potential confounding. RESULTS: Among the case patients, 81% were ELISA positive and 86% had antibodies to CagA. The corresponding numbers among the controls were 58% and 55%, respectively. ELISA positivity was associated with an increased risk of gastric adenocarcinoma compared to ELISA negativity (OR for gastric cancer regardless of site 3.9, 95% CI 1.9-8.2). The OR was 7.4 (95% CI 3.3-16.6) for CagA-positive relative to CagA-negative subjects. Among ELISA-positive subjects the presence of CagA antibodies increased the risk 3.6 times (95% CI 1.2-11.1). ELISA-positive CagA-negative infections were associated with a fourfold increased risk (OR = 4.2, 95% CI 1.0-17.0) compared to no infection (ELISA-negative and CagA-negative). CONCLUSIONS: Although patients with antibodies to CagA have the greatest risk of developing gastric cancer, those with CagA-negative infections run a significantly greater risk than uninfected persons.