Local cytokine response in Helicobacter pylori-infected subjects

The host immune response to Helicobacter pylori infection might be of importance with regard to the outcome of infection by this organism, e.g., to explain why only a proportion of infected subjects develop peptic ulcers. In this study we have analyzed the local response of different cytokines-i.e., the proinflammatory interleukin-1beta, (IL-1beta), IL-6, tumor necrosis factor alpha, and IL-8; the immunoregulatory gamma interferon (IFN-gamma); and IL-4; and the anti-inflammatory transforming growth factor beta (TGF-beta)-in antral biopsy specimens from H. pylori-infected duodenal ulcer (DU) patients and asymptomatic (AS) carriers (i.e., with chronic gastritis only). For comparison, biopsy specimens from uninfected healthy individuals were also analyzed. An immunohistochemical technique was used to allow quantification of the cytokine responses as well as identification of the cell types associated with the cytokine expression. We found that the levels of all of the studied cytokines except IL-4 were increased in the H. pylori-infected subjects compared to the levels in the healthy individuals. Our results indicate that the antral cytokine response is of the Th1 type since IFN-gamma, but not IL-4, was up-regulated both in H. pylori-infected DU patients and in AS carriers. However, there were no significant differences in either proinflammatory or immunoregulatory cytokine levels when H. pylori-infected subjects with and without peptic ulcers were compared. Some of the cytokines, particularly IL-1beta and TGF-beta, were also found in the gastric mucosae of healthy, uninfected subjects. We also showed that the gastric epithelium contributes substantially to the antral cytokine response of the proinflammatory cytokines IL-1beta and IL-6 in addition to IL-8.

Surface proteins from Helicobacter pylori exhibit chemotactic activity for human leukocytes and are present in gastric mucosa

The mechanism by which Helicobacter pylori, a noninvasive bacterium, initiates chronic antral gastritis in humans is unknown. We now show that H. pylori releases products with chemotactic activity for monocytes and neutrophils. This chemotactic activity was inhibited by antisera to either H. pylori whole bacteria or H. pylori-derived urease. Moreover, surface proteins extracted from H. pylori and purified H. pylori urease (a major component of the surface proteins) exhibited dose-dependent, antibody-inhibitable chemotactic activity. In addition, a synthetic 20-amino acid peptide from the NH2-terminal portion of the 61-kD subunit, but not the 30-kD subunit, of urease exhibited chemotactic activity for monocytes and neutrophils, localizing the chemotactic activity, at least in part, to the NH2 terminus of the 61-kD subunit of urease. The ability of leukocytes to chemotax to H. pylori surface proteins despite formyl-methionyl-leucyl-phenylalanine (FMLP) receptor saturation, selective inhibition of FMLP-mediated chemotaxis, or preincubation of the surface proteins with antiserum to FMLP indicated that the chemotaxis was not FMLP mediated. Finally, we identified H. pylori surface proteins and urease in the lamina propria of gastric antra from patients with H. pylori-associated gastritis but not from uninfected subjects. These findings suggest that H. pylori gastritis is initiated by mucosal absorption of urease, which expresses chemotactic activity for leukocytes by a mechanism not involving N-formylated oligopeptides.

MUC6 apomucin shows a distinct normal tissue distribution that correlates with Lewis antigen expression in the human stomach

BACKGROUND & AIMS

Among the human mucin complementary DNAs thus far identified, two (MUC5AC and MUC6) were cloned from stomach libraries. This study examines the distribution of MUC6 in normal tissues and compares it with that of MUC5AC as well as with the expression of Lewis blood group antigens.

METHODS

Affinity-purified rabbit antibodies detecting epitopes within the repetitive sequence of MUC5AC and MUC6 were used in enzyme-linked immunosorbent assays and immunohistochemical assays. RNA expression was analyzed by in situ hybridization. Double-labeling immunofluorescence was used to study apomucin and Lewis antigen coexpression.

RESULTS

MUC6 is detected in the stomach, colon, gallbladder, and endocervix. Two patterns of staining are observed, perinuclear and diffuse cytoplasmic, possibly reflecting differences in MUC6 glycosylation. Using both immunohistochemical assays and in situ hybridization on stomach tissue sections, MUC6 is expressed mainly in antral mucous cells, whereas MUC5AC is detected mainly in the superficial epithelium and neck glands. In antral mucosa, MUC6+ cells express Lewis(y), whereas MUC5AC+ cells express Lewis(b) and sialyl-Lewis(a).

CONCLUSIONS

It was concluded that MUC6 has a distinct tissue distribution pattern, different from that of MUC1-MUC5; MUC5AC and MUC6 are expressed by different cellular populations in normal stomach; and in this tissue, MUC5AC+ cells and MUC6+ cells show different patterns of Lewis antigen expression.

Different cytokine profile and antigen-specificity repertoire in Helicobacter pylori-specific T cell clones from the antrum of chronic gastritis patients with or without peptic ulcer

Helicobacter pylori (Hp) infection almost invariably results in chronic antral gastritis, but only a proportion of patients develop peptic ulcer. Some Hp strains may be more ulcerogenic than others, but some ulcerogenic mechanisms may also depend on the type of the host immune response. In this study, the antigen specificity and the cytokine profile of 53 Hp-specific CD4+ T cell clones derived from the antral mucosa of five patients with Hp-induced uncomplicated chronic gastritis (CG) were assessed and compared with those of 34 Hp-specific CD4+ T cell clones derived from six Hp-infected patients with chronic gastritis and peptic ulcer (CG-PU). The majority (28/34; 82%) of gastric Hp-specific T cell clones from CG-PU patients expressed the Th1 profile and 17 (all Th1) of the 34 clones were specific for cytotoxin-associated protein (CagA). In contrast, 34 (64%) of the 53 Hp-specific gastric T cell clones derived from CG patients were able to secrete both Th1 and Th2 cytokines (Th0 profile) and only 36% expressed a polarized Th1 profile. The majority (85%) of Hp-specific clones from CG patients recognized Hp antigens other than CagA, since 13/53 (25%) were specific for urease, 6 (11%) for VacA, 6 (11%) for HSP and 20 (38%) for other undefined Hp antigens. Results provide evidence that the type of T helper cell response against Hp may vary according to the antigen involved and suggest that a polarized Th1 response may play a role in the genesis of peptic ulcer, whereas a local Th0 response, including interleukin-4 production, may represent an individual host factor which contributes to lower the degree of gastric inflammation and prevent ulcer complication.

Antrum- and corpus mucosa-infiltrating CD4(+) lymphocytes in Helicobacter pylori gastritis display a Th1 phenotype

In this study, cytokine patterns produced by CD4(+) T cells isolated from antrum or corpus gastral biopsy specimens of 10 patients with Helicobacter pylori-positive gastritis were compared. To this end, expression of intracellular cytokines (interleukin-4 [IL-4] and gamma interferon) and of CD4 was assessed by flow cytometry. Ten to 60% of the isolated CD4(+) T cells produced gamma interferon upon stimulation. With the exception of one patient, IL-4-positive CD4(+) cells were not detected. Therefore, CD4(+) cells infiltrating antrum and corpus stomach mucosa during H. pylori infection show a Th1 phenotype. This polarized Th1-type response may contribute to the inability of the immune system to eradicate H. pylori infection.

Mucosal gastrin concentration, molecular forms of gastrin, number and ultrastructure of G-cells in patients with duodenal ulcer

The mean antral immunoreactive gastrin (IRG) concentration of 38 duodenal ulcer (DU) patients was significantly higher (35-9+/-5-2 mug/g) than that of 21 controls (15-9+/-2-6 mug/g). Also the mean IRG concentration in the proximal duodenal mucosa of 15 DU patients (3-2+/-0-8 mug/g) was higher (but not significantly) than that of 10 controls (1-8+/-0-5 mug/g). The number of G-cells in the antral mucosa of 58 DU patients and in the duodenal mucosa of 29 DU patients was not larger than that of controls. The distribution of immunoreactivity in gastrin components has been investigated in the antral and duodenal mucosa of six DU patients and six controls. In the antral mucosa the mean percentage of G-17 was 93-3% in DU patients and 92-0% in controls. G-34 amounted to 4-0% in DU patients and to 5-0% in controls. The G-34 percentage in the duodenal mucosa was higher (however not significantly) in the DU patients than in the controls (50-1% versus 35-8%). Ultrastructurally, the antral G-cells of DU patients had a significantly lower density index of their secretory granules suggesting higher functional activity. It is concluded that the exaggerated serum IRG response of DU patients to different stimuli is not a consequence of an increased G-cell mass.

Gastric mucosal recognition of Helicobacter pylori is independent of Toll-like receptor 4

Little is known about the interactions between Helicobacter pylori, which specializes in colonizing the mucin layer that covers the gastric mucosa, and primary gastric epithelial cells. The expression pattern of Toll-like receptors (TLRs) in primary gastric epithelial cells and cell lines was compared. Primary cells did not express TLR4, whereas all cell lines expressed a nonsignaling form of TLR4. Because other cells within the mucosa expressed TLR4, it was next investigated whether H. pylori can be recognized by TLR4--they cannot. Moreover, H. pylori infection of primary cells induced a regulated production of interleukin (IL)-6, IL-8, and tumor necrosis factor-alpha, whereas infection of cell lines only resulted in IL-8 production. The cytokine production in all cell types was strictly cag dependent. These findings indicate that, although the epithelium is important in directing the immune response against H. pylori infections, the response is independent of TLR4.

Expression and activation of NF-kappa B in the antrum of the human stomach

Both in vitro studies and experiments in mice suggest a key role for transcription factor NF-kappa B as a mediator of mucosal inflammation. Experiments in vitro show that NF-kappa B activation may be a critical event in the production of proinflammatory molecules in Helicobacter pylori-associated gastritis. This study examines the expression and activity of NF-kappa B in situ in antral biopsies of 69 consecutive patients with immunohistochemical techniques. In the uninflamed stomach, NF-kappa B was highly expressed and active in a subset of epithelial cells, which were identified as predominantly G cells. In accordance with this activity, G cells were shown to express high levels of the NF-kappa B target cytokine TNF-alpha, a well-documented stimulator of gastrin production. In patients with H. pylori-associated gastritis, NF-kappa B activity was markedly enhanced. Activation occurred preferentially in the epithelial cells. The number of cells showing activated NF-kappa B correlated with the activity of gastritis, a measure of neutrophil influx, whereas no correlation was found with the chronicity of inflammation, a measure of the presence of mononuclear inflammatory cells. This correlation is direct evidence of the importance of NF-kappa B-dependent signal transduction for neutrophil influx in H. pylori-associated gastritis.

Inflammatory gene profiles in gastric mucosa during Helicobacter pylori infection in humans

Helicobacter pylori infection is associated with an inflammatory response in the gastric mucosa, ultimately leading to cellular hyperproliferation and malignant transformation. Hitherto, only expression of a single gene, or a limited number of genes, has been investigated in infected patients. cDNA arrays were therefore used to establish the global pattern of gene expression in gastric tissue of healthy subjects and of H. pylori-infected patients. Two main gene expression profiles were identified based on cluster analysis. The data obtained suggest a strong involvement of selected Toll-like receptors, adhesion molecules, chemokines, and ILs in the mucosal response. This pattern is clearly different from that observed using gastric epithelial cell lines infected in vitro with H. pylori. The presence of a "Helicobacter-infection signature," i.e., a set of genes that are up-regulated in biopsies from H. pylori-infected patients, could be derived from this analysis. The genotype of the bacteria (presence of genes encoding cytotoxin-associated Ag, vacuolating cytotoxin, and blood group Ag-binding adhesin) was analyzed by PCR and shown to be associated with differential expression of a subset of genes, but not the general gene expression pattern. The expression data of the array hybridization was confirmed by quantitative real-time PCR assays. Future studies may help identify gene expression patterns predictive of complications of the infection.

Atrophic Autoimmune Pangastritis: A Distinctive Form of Antral and Fundic Gastritis Associated With Systemic Autoimmune Disease

The 2 major recognized forms of atrophic gastritis are autoimmune and environmental atrophic gastritis. These differ in their topographical distribution in the stomach, histologic features, and etiology. Autoimmune atrophic gastritis results from immune-mediated destruction of specialized oxyntic glands, is restricted to the body and fundus, and shows characteristic neuroendocrine hyperplasia. Environmental atrophic gastritis is associated with long-standing Helicobacter pylori infection and preferentially involves antrum and transition zone mucosa. In this study, we describe a distinctive form of atrophic gastritis that differs markedly from both of these classic variants. This gastritis is characterized by: (1) intense mucosal inflammatory infiltrates, persisting even into the phase of severe glandular atrophy, (2) pangastric distribution with diffuse involvement of both body and antrum, (3) lack of association with H. pylori, and (4) lack of neuroendocrine hyperplasia. The 8 patients presented ranged from 1 to 75 years and showed a slight female predominance (5F:3M). All had systemic autoimmune and/or connective tissue diseases including autoimmune enterocolitis (4 cases), systemic lupus erythematosus, refractory sprue, autoimmune hemolytic anemia, and disabling fibromyalgia. Positive serum autoimmune markers were documented in 7 of 8 (87%) patients, but serologies for antiparietal cell and anti-intrinsic factor antibodies were undertaken in only 1 patient each and were negative. We propose that the distinctive histology of this form of atrophic pangastritis and its association with systemic autoimmune disease suggests an autoimmune process directed against multiple cell lineages in the stomach. The development of multifocal low-grade dysplasia in 1 patient, a 19-year-old woman, suggests that this condition might have neoplastic potential.

Helicobacter pylori modulation of gastric and duodenal mucosal T cell cytokine secretions in children compared with adults

BACKGROUND

In contrast to adults, ulcers are un-common in Helicobacter pylori-infected children. Since immunological determinants influence the outcome of H. pylori infection, we have investigated mucosal T cell responses in H. pylori-infected children and compared them with those of adults and negative controls.

MATERIAL AND METHODS

Mucosal biopsies were obtained from 43 patients undergoing an upper GI endoscopy for dyspeptic symptoms. The concentrations of released cytokines and the density of CD3+, CD25+ and CD69+cells were evaluated by flow cytometry, and the numbers of cytokine-secreting cells were measured by ELISPOT.

RESULTS

The numbers of isolated antral CD3+ lymphocytes were only significantly raised in infected adults compared with noninfected controls (p < 0.05), whereas the proportion of CD3+ cells expressing activation markers (CD25 or CD69) remained low. In the stomach, IFN-gamma concentrations increased in infected children and infected adults compared with controls (p < 0.05), but IFN-gamma concentrations were tenfold lower in children than in adults (p < 0.01). IL-2, IL-4, IL-10 and TNF-alpha concentrations were similar in infected and in uninfected children and adults. In contrast, in the duodenum, IFN-gamma, as well as IL-4 and IL-10 concentrations were only increased in infected children compared with controls (p < 0.05). The concentrations of these cytokines were similar in both groups of adults who, however, like children, displayed a higher number of duodenal IL-4-secreting cells compared to controls (p < 0.05).

CONCLUSION

These results suggest that IFN-gamma secretion in the stomach of H. pylori-infected patients is lower in children than in adults. This could protect children from development of severe gastro-duodenal diseases such as ulcer disease. In addition, infected patients are characterised by a dysregulation of the mucosal cytokine secretion at distance from the infection site.

Increased frequency of activated T-cells in the Helicobacter pylori-infected antrum and duodenum

Helicobacter pylori colonize the human stomach and duodenum. The infection has been shown to induce a strong T-cell response in the stomach, whereas the response within the duodenum has been poorly characterized. Furthermore, it remains to be elucidated whether the T-cell response may contribute to ulcer formation in the host. In this study, the frequency of different T-cell subsets, their degree of activation and expression of co-stimulatory receptors in biopsies from the duodenum as well as the antrum were studied by immunohistochemistry and flow cytometry. It was also evaluated whether there are differences in the T-cell responses between duodenal ulcer patients and asymptomatic carriers that might explain why only 10-15% of the infected subjects develop duodenal ulcers. The frequencies of CD4+, CD8+ and CD45RO+, i.e. memory T-cells, were significantly increased in the antrum, and the number of CD25+ cells was considerably higher in both the antrum and duodenum of duodenal ulcer patients and asymptomatic carriers as compared to uninfected individuals. Interestingly, the levels of immunosuppressive CTLA-4+ cells were significantly higher in the duodenum of duodenal ulcer patients, as compared to the asymptomatic carriers. H. pylori cause activation of T-cells in the duodenum as well as in the stomach. Our observation of higher levels of CTLA-4+ cells in the duodenum of duodenal ulcer patients than in the asymptomatic carriers suggests that a suppressive T-cell response may be related to the development of duodenal ulcers.

Quantitative distribution of immunoglobulin-producing cells in gastric mucosa: relation to chronic gastritis and glandular atrophy

Immunoglobulin (Ig)-producing immunocytes were quantified by paired immunofluorescence staining in specimens of gastric antral (n = 52) and body (n = 117) mucosa obtained from 45 patients with various gastrointestinal disorders. Enumerations were carried out in a 500 micron wide zone from the muscularis mucosae to the lumen ('tissue unit'). The specimens were divided into three categories according to the degree of inflammation, and each specimen received a grade for atrophy (0-2). The total number of IgA-, IgM- and IgG-producing cells per tissue unit increased strikingly with increasing degree of inflammation, both in antral and body mucosa. IgA immunocytes predominated (61-91%) in all specimens, but the IgG isotype showed the largest relative increase (four to 17-fold), particularly in the basal part of the mucosa. In this layer of the gastric body the proportion of IgG cells was also significantly raised in association with atrophy, irrespective of degree of inflammation. Locally produced IgG may be of protective significance in terms of internal (or 'second line') defence but may at the same time maintain immunopathological mechanisms contributing to the chronicity of gastritis.

Hypergastrinemia in response to gastric inflammation suppresses somatostatin

Hypergastrinemia and a reduction in tissue somatostatin occur in Helicobacter pylori-infected patients. We investigated whether the D cell may be a direct target of gastric inflammation and hypergastrinemia. D cells were quantified by morphometry and flow cytometry in 16-wk-old wild-type (G+/+) and gastrin-deficient (G-/-) mice. Hypochlorhydric G-/- mice were treated with either antibiotics for 20 days or infused with gastrin (G-17) for 14 days. G+/+ mice were made hypochlorhydric by treating them with omeprazole for 2 mo. G-/- mice showed significant inflammation compared with the G+/+ mice, which resolved after 20 days of antibiotic treatment. D cell numbers were not significantly different between G-/- and G+/+ mice. After G-17 was infused, fundic and antral D cell numbers decreased in the G-/- mice. G+/+ animals made hypergastrinemic with omeprazole exhibited decreased D cell numbers. When omeprazole-treated mice were treated with antibiotics alone, elevated plasma gastrin levels returned to baseline and D cell numbers returned to resting levels despite persistent hypochlorhydria. Hypergastrinemia, induced by inflammation, results in decreased D cell numbers. Thus the stomach responds to the presence of inflammation by reducing somatostatin levels, thereby releasing the inhibition on the G and parietal cells to maximize gastric acid output.

Randomised placebo-controlled double-blind trial of two dosages of sodium cromoglycate in treatment of varioliform gastritis: comparison with cimetidine

Eighteen patients with diffuse varioliform gastritis were enrolled in a double-blind, placebo-controlled trial of sodium cromoglycate, 200 mg a day, and sodium cromoglycate, 400 mg a day, for 28 days. An additional six patients were treated with cimetidine 1 g daily for 28 days. The improvement in terms of patient's subjective assessment, endoscopic assessment, and immunohistochemical measurements of IgE cells in the mucosa was significantly greater in patients given sodium cromoglycate than that in those given cimetidine or placebo. The results provide evidence that type 1 hypersensitivity plays some part in the pathogenesis of varioliform gastritis. It is, therefore, important to differentiate this condition from other types of gastritis, as treatment with sodium cromoglycate appears to be affective.

Russell body gastritis: expanding the spectrum of Helicobacter pylori - related diseases?

We report a new case of Helicobacter pylori gastritis showing plasma cell infiltrates with extensive formation of Russell bodies (Mott cells) within the lamina propria of the antral mucosa. The patient was a 60-year-old woman with a history of epigastric pain. Endoscopy revealed non-specific congestion of the mucosa. Microscopically, the intracytoplasmic inclusions were homogeneous, mainly round to oval, and pushed the nucleus toward the periphery. They were intensely PAS-positive and reacted to antibodies against polytypic light chains, CD79a, and anti-plasma cell antibody. Because of the accumulation of intracytoplasmic inclusions, Russell body gastritis is a potential source of diagnostic difficulties in endoscopic biopsy specimens that can be confused with immunocytic neoplasms, such as lymphoplasmacytic lymphoma or plasmocytoma, or signet-ring cell carcinoma. In the light of similar cases published previously, it seems as if the association between Russell body gastritis and Helicobacter pylori infection is not merely coincidental.

Autoantibodies to gastrin-producing cells in antral (type B) chronic gastritis

Autoantibodies that react exclusively with the gastrin-secreting cell of human antrum have been detected by immunofluorescence in eight of 106 patients with histologic evidence of chronic atrophic gastritis, Type B, involving mainly the antrum. These antibodies were of the IgG class and of low titer. However, follow-up studies one to two years later showed persistently positive reactions, despite symptomatic treatment. These data support the concept of an autoimmune variant of chronic "antral" gastritis, Type B.

Ethnic difference of Helicobacter pylori gastritis: Korean and Japanese gastritis is characterized by male- and antrum-predominant acute foveolitis in comparison with American gastritis

AIM: To investigate the clinicopathological factors underlying the ethnic differences of Helicobacter pylori gastritis and cancer.

METHODS: We analyzed clinicopathological parameters of gastric biopsies having H pylori infection that were randomly selected from different ethnic populations including 147 Americans, 149 Japanese, and 181 Koreans.

RESULTS: Males were predominant in Japanese and Korean populations (77.9 and 67.4% respectively) in comparison with Americans (48.3%) (P<0.001). H pylori gastritis in Koreans and Japanese was characterized by the predominant antral involvement. In the antrum, neutrophilic infiltration into the proliferative zone of pit, i.e., acute foveolitis, was more frequent in Koreans (82%) than in Japanese (71%) (P<0.05) and Americans (61%) (P<0.001). Interstitial neutrophilic infiltration, intestinal metaplasia and atrophy were also frequent in Koreans and Japanese. In the body, the prevalence of acute foveolitis was not significantly different among the populations while chronic interstitial inflammation and lymphoid follicles were more pronounced in the body of Americans than in the body of others (P<0.01).

CONCLUSION: The male-, and antrum-predominant H pylori gastritis in Koreans and Japanese is compatible with the pattern of sex and topographical distribution of gastric cancer incidence. Our data suggest that persistent acute foveolitis at the proliferative zone is a crucial step in the gastric carcinogenesis.

The histopathological spectrum of type A gastritis

It has been recently shown that type A gastritis can be histologically diagnosed in the preatrophic stage. In order to evaluate whether parietal cell atrophy in AG might correlate with other histopathological findings in the antral and body mucosa, we retrospectively investigated 171 consecutive cases of histologically diagnosed preatrophic (active) or atrophic type A gastritis (H&E, Warthin-Starry). The prevalences of intestinal metaplasia (75% vs 44.4%) and micronodular hyperplasia (86.1% vs 52.4%) of endocrine cells in the oxyntic mucosa were significantly higher of parietal cell atrophy was present (p < 0.001 and p < 0.0001, respectively), whereas the prevalence of nodular lymphoid aggregates (77.8% vs 48.1%) and of Helicobacter pylori (14.3% vs 1.9%) in the oxyntic mucosa was significantly higher if parietal cell atrophy could not be detected (p < 0.001 and p < 0.01, respectively). In the antral mucosa, altered patterns of the inflammatory reaction could be demonstrated independent of the parietal cell mass possibly caused by impaired gastric acid production. Our data support the notion that the development of parietal cell atrophy in type A gastritis represents a stepwise process including initial pseudohypertrophy of these cells.

Immunochemical characterization of gastrin in pancreatic islets of normal and genetically obese mice

Material with gastrin-like immunoreactivity has been extracted from micro-dissected islets and from antral mucosa of normal and genetically obese mice. The islet and antral extracts cross-reacted with antisera specific for the CO2H-terminal portion of human heptadecapeptide gastrin, but did not cross-react with antisera specific for the NH2-terminal region or with an antiserum specific for the entire, intact, molecule. With the antiserum showing highest cross- reactivity, the concentration of immunoreactive gastrin in normal islet tissue (138 pmol/g, standard human G17-I) was approximately 50% that in obese mouse islets (204 pmol/g) and 2% that in normal antral mucosa (6-1 nmol/g). Following fractionation on Sephadex G-50 the principal forms of gastrin in the islet and antral extracts had similar elution volumes to human heptadecapeptide gastrin, although other, probably smaller, forms of gastrin were also noted in the islet extracts.

Blood and gastric FOXP3+ T cells are not decreased in human gastric graft-versus-host disease

Previous studies suggest regulatory T cells (Tregs) inhibit graft-versus-host disease (GVHD) in mouse and human hematopoietic cell transplant (HCT) recipients. As the gastrointestinal tract represents one of the most common and severe sites of GVHD-related tissue damage, we sought to determine whether a deficit in circulating or gastric mucosal Treg numbers correlates with the clinical onset of gastric GVHD. We used the marker FOXP3 to quantify Tregs in blood and in gastric antral biopsies in a cohort of 60 allogeneic HCT recipients undergoing endoscopy at a single center to evaluate symptoms suspicious for gastrointestinal GVHD. We show for the first time in the gastric mucosa and, contrary to existing reports, in the blood, that the percent of T cells expressing FOXP3 is at least as high in the presence as in the absence of GVHD involving the upper gut. There was no correlation of Treg frequency with the histologic or clinical severity of gastrointestinal GVHD. We conclude that Treg depletion is not a central feature in the pathogenesis of gastric GVHD in humans.

Intracellular topography of immunoreactive gastrin demonstrated using electron immunocytochemistry

Gastrin (G)-producing cells from the mammalian gastric antrum have been investigated using computer-assisted morphometry and a novel double colloidal gold-labeled-immunoglobulin electron immunocytochemical procedure. Correlation analysis of human antral G-cells indicates (p less than 0.001) that a single population of granules exists with small (160 nm) electron-dense and large (240 nm) electron-lucent forms representing the extremes. Non-crossreacting region-specific antisera have been used to visualize G-17 and G-34 (progastrin) to the small electron-dense granules and G-17 to the other intermediate forms. From the results we propose a topographic segregation of immunoreactive gastrins within 2 apparently distinct granule subclasses and suggest that this may represent the pathway of granule maturation.

Increased Frequency of Antral CD4+ T and CD19+ B Cells in Patients with Helicobacter pylori-Related Peptic Ulcer Disease

Only a fraction of Helicobacter pylori (HP)-infected individuals develop clinical disease. Recent research indicates that immunological mechanisms may be important for understanding the pathophysiology of HP infection. Differences in the individual cellular immune response may reflect the clinical diversity. The aim of the present study was to investigate the cellular immune response against HP in three clinically well-defined patient groups: HP-positive peptic ulcer, HP-positive and HP-negative gastritis. Biopsies from gastric mucosa were processed for analysis by flow cytometry and histology. The number of T lymphocytes (CD3+) was significantly higher in HP-positive peptic ulcer (13.8%) than in HP-positive nonulcer gastritis (6.3%). A nonsignificant increase for B lymphocytes (CD19+) was noted as well. Furthermore, a significant difference was seen in mucosal CD4/CD8 ratio between HP ulcer (2.4) and nonulcer HP gastritis (1.0) patients. Thus, B cells (CD19+) and T-helper cells (CD4+) were dominant in gastric mucosa from peptic ulcer patients, and cytotoxic T cells (CD8+) were relatively dominant in gastric mucosa from nonulcer patients. In conclusion, distinct differences in the T-cell subset distribution of mucosal lymphocytes were detected in patients with HP infection, strongly correlated with the presence or absence of peptic ulcer.

Anti-CagA immunoglobulin G responses correlate with interleukin-8 induction in human gastric mucosal biopsy culture

Helicobacter pylori persists in the human stomach despite eliciting both cellular and humoral immune responses and inducing proinflammatory cytokines. To determine whether local humoral and cytokine responses are related to each other and to histologic responses, we studied 66 Japanese patients who underwent gastroscopy. Using specific enzyme-linked immunosorbent assays, we examined gastric antral mucosal-organ biopsy culture supernatants to assess interleukin-6 (IL-6) and interleukin-8 (IL-8) levels and antibody responses to H. pylori whole-cell antigens CagA, HspA, and HspB. Of the patients studied, 11 were H. pylori negative and 55 were H. pylori positive; by PCR, all strains were cagA(+). As expected, compared to H. pylori-negative patients, H. pylori-positive patients had significantly higher humoral responses to all H. pylori antigens and had higher IL-8 (47.8+/-3.5 versus 10.1+/-4.3 ng/mg of biopsy protein; P<0.001) and IL-6 levels (2.8+/-0.3 versus 0.26+/-0.2 ng/mg of protein; P<0.001). Among the H. pylori-positive patients, supernatant anti-CagA immunoglobulin G (IgG) levels were significantly associated with H. pylori density (P<0.005) and neutrophil infiltration (P<0.005) scores. Anti-CagA immunoglobulin A levels were correlated with intestinal metaplasia (P<0.05). Mononuclear cell infiltration scores were significantly associated with supernatant IL-6 levels (P<0.005) and with IgG responses to whole-cell antigens (P<0.05). Supernatant IL-8 levels were significantly associated with anti-CagA IgG (r = 0.75, P<0.001). Anti-CagA responses correlated with neutrophil infiltration, intestinal metaplasia, H. pylori density, and IL-8 levels, suggesting that the absolute levels of these antibodies may be markers for gastric inflammation and premalignant changes in individual hosts.