Gluten induces an intestinal cytokine response strongly dominated by interferon gamma in patients with celiac disease

The interferon gamma gene in celiac disease: augmented expression correlates with tissue damage but no evidence for genetic susceptibility

Celiac disease (CD) is a complex genetic disorder characterized by gluten intolerance. The Th1 immune response, with a key position for interferon gamma (IFN-gamma), is an important determinant of intestinal remodeling in CD. We aimed at further ascertaining the role of IFN-gamma, either as a genetic factor in the etiology, or as a facilitator of disease initiation/progression. Duodenal biopsies were sampled across distinct histopathological stages of the disease, including refractory CD (RCD), and used to determine IFN-gamma gene (IFNG) expression by real-time RT-PCR. INFG expression correlated with the extent of tissue restructuring, reaching a 240-fold higher expression in total villous atrophy compared to healthy tissue. CD and RCD patients with similar lesions had comparable expression levels. Interestingly, patients in complete remission still had 7.6-fold residual over-expression. An INFG marker was tested in three cohorts of Dutch patients for both genetic linkage and association. Linkage analysis yielded no significant scores for IFNG or its flanking markers. In addition, IFNG allele frequencies were not differently distributed between cases and controls. Likewise, all alleles were randomly transmitted to affected children in parents-case trios. There is no evidence for IFNG as a predisposing gene in CD, despite its enhanced expression in patients in complete remission.

The pathogenesis of coeliac disease

Coeliac disease is a chronic enteropathy caused by intolerance to gluten proteins. The true prevalence of this condition is greater than previously thought, with increasing numbers of 'silent' cases being diagnosed. Untreated coeliac disease is associated with significant morbidity and increased mortality. There have been a number of advances in our understanding of the pathogenesis of coeliac disease, in particular the mechanisms whereby gluten epitopes are processed, become modified by tissue transglutaminase (tTG) and then interact with HLA restricted T cells. An improved understanding of the immune response to gluten is likely to lead to the development of novel strategies for the treatment of coeliac disease.

A functional variant of IFNγ gene is associated with coeliac disease

In coeliac disease (CD) a profile of proinflammatory cytokines are secreted interferon gamma (IFNgamma) being one of the most important. A dinucleotide polymorphism consisting of a variable number of CA repeats related with IFNgamma production levels, has been reported on the first intron of the IFNgamma gene. The aim of this study was to analyse the influence of the functional IFNgamma CA repeats in CD predisposition through familial and case-control studies. The familial analysis showed that the 124 bp allele was significantly more transmitted to the affected offspring (P=0.02), while the 126 bp allele showed a statistically significant nontransmission pattern (P=0.01). Nevertheless, in the case-control analysis, we could not find a direct association of CA repeats with CD. This fact might be due to parent-of-origin effect in the IFNgamma CA polymorphism. Our data suggest a possible role of IFNgamma CA polymorphism in CD susceptibility.

Increased incidence of autoimmune disorders as a late complication in children with early onset dermatitis and/or milk allergy

Subjects with atopic dermatitis and autoimmune disorders share some similar immune response disorders. The aim of this study was to see whether subjects with early onset atopic dermatitis run a risk of eventually developing autoimmune diseases. The results of a questionnaire of 145 adolescents (70 f, 75 m, mean age 18.2 years, range 16-23 years) was compared with those of a group of 262 controls (112 f, 150 m, mean age 17.5 years, range 16-21 years), 164 of whom reported no atopic symptoms and were treated as a separate group for statistical analysis. As compared with the non-atopic controls, the study group subjects showed a significantly increased incidence of autoimmune disorders (9% vs. 1%), the relative risk ratio of a subject with infantile onset atopic eczema getting a gastrointestinal (GI) immune-mediated disease being 2.4 (CI(95)2.1-2.8) and of getting some other autoimmune disorder 3.1 (CI(95)2.8-9.7). The positive skin prick tests showed a negative association with the manifestation of a GI or other autoimmune disorder. The subjects with infantile dermatitis also reported recurrent abdominal pains (23% vs. 15%), and milk-induced gastrointestinal symptoms (19% vs. 10%) significantly more even as young adults than the controls. Our study showed that infantile atopy increases a predisposition to autoimmune disorders, suggesting that these two entities might have a common immunological determinant. While a high incidence of chronic GI complaints among the study subjects suggests the ongoing activity of local immune responses. However, more detailed prospective studies are needed to confirm these observations.

cDNA microarray analysis of gene expression in coeliac disease jejunal biopsy samples

In coeliac disease in the jejunum of a genetically susceptible person wheat gliadin and related prolamins from rye and barley trigger an immunological reaction, which induces small-bowel mucosal transformations, villous atrophy and crypt hyperplasia. Though CD4+ specific T cells, intraepithelial lymphocytes, infiltrating plasma cells and autoantibodies are known to have an effect on the coeliac disease, the pathogenic mechanisms leading to the tissue injury remain to be elucidated. Our aim was to find novel gene transcripts, which might have a role in coeliac disease pathogenesis. The gene expression in duodenal biopsy samples from untreated coeliac patients (n=4), patients on gluten-free diet (n=4) and healthy controls (n=4) was studied by cDNA microarray analysis. The method allows monitoring of the expression of thousands of genes simultaneously. Compared to healthy controls, the expression of 156 and 60 genes was changed in untreated and treated coeliac disease, respectively. Between treated and untreated coeliac disease, 98 genes had altered expression. Of the 5184 genes or expressed sequence tags, altogether 263 were affected. Many of these genes are directly or indirectly connected to T-cell activation, B-cell maturation or epithelial cell differentiation. By the microarray method, numerous genes were found to evince altered mRNA expression in coeliac disease. The method holds promise in exploring the pathogenetic mechanisms in the small bowel and may reveal new target genes for the therapy of coeliac disease.

Transcriptional downregulation of tight junction protein ZO-1 in active coeliac disease is reversed after a gluten-free diet

Coeliac disease is an autoimmune enteropathy characterized by an enhanced permeability of the intestinal epithelial barrier. In epithelial cells paracellular permeability is regulated by intercellular tight junction. The cytoplasmic protein ZO-1 interacts directly with F-actin and plays a pivotal role in the structural and functional organization of tight junction.

AIM

The aim of this study was to investigate the expression and localization of ZO-1 in the intestinal mucosa of coeliac patients.

PATIENTS AND METHODS

Twenty patients with active coeliac disease, seven of whom underwent a repeat biopsy following a gluten-free diet and 27 control subjects, were studied. In all subjects, three biopsies were obtained from distal duodenum during upper gastrointestinal endoscopy. ZO-1 protein localization and levels were detected by immunofluorescence followed by confocal microscopy analysis and immunoblotting. ZO-1 mRNA expression was assessed by RT-PCR. F-actin distribution was also investigated.

RESULTS

In patients with active coeliac disease, both ZO-1 protein levels and mRNA were clearly reduced. Cytoskeletal organization was disrupted with F-actin staining concentrated at the subcortical and basal surface regions. Abnormalities in ZO-1 expression and actin organization were reversed after a gluten-free diet.

CONCLUSIONS

In active coeliac disease, ZO-1 protein expression is downregulated at the transcriptional level in association with F-actin redistribution. These changes are completely reversed after a gluten-free diet and could contribute to the increased intestinal paracellular permeability observed in this disorder.

Presence of bacteria and innate immunity of intestinal epithelium in childhood celiac disease

OBJECTIVES

Exposure to gliadin and related prolamins and appropriate HLA-DQ haplotype are necessary but not sufficient for contracting celiac disease (CD). Aberrant innate immune reactions could be contributing risk factors. Therefore, jejunal biopsies were screened for bacteria and the innate immune status of the epithelium investigated.

METHODS

Children with untreated, treated, challenged CD, and controls were analyzed. Bacteria were identified by scanning electron microscopy. Glycocalyx composition and mucin and antimicrobial peptide production were studied by quantitative RT-PCR, antibody and lectin immunohistochemistry.

RESULTS

Rod-shaped bacteria were frequently associated with the mucosa of CD patients, with both active and inactive disease, but not with controls. The lectin Ulex europaeus agglutinin I (UEAI) stained goblet cells in the mucosa of all CD patients but not of controls. The lectin peanut agglutinin (PNA) stained glycocalyx of controls but not of CD patients. mRNA levels of mucin-2 (MUC2), alpha-defensins HD-5 and HD-6, and lysozyme were significantly increased in active CD and returned to normal in treated CD. Their expression levels correlated to the interferon-gamma mRNA levels in intraepithelial lymphocytes. MUC2, HD-5, and lysozyme proteins were seen in absorptive epithelial cells. beta-defensins hBD-1 and hBD-2, carcinoembryonic antigen (CEA), CEA cell adhesion molecule-1a (CEACAM1a), and MUC3 were not affected.

CONCLUSIONS

Unique carbohydrate structures of the glycocalyx/mucous layer are likely discriminating features of CD patients. These glycosylation differences could facilitate bacterial adhesion. Ectopic production of MUC2, HD-5, and lysozyme in active CD is compatible with goblet and Paneth cell metaplasia induced by high interferon-gamma production by intraepithelial lymphocytes.

Association of FAS (TNFRSF6)-670 gene polymorphism with villous atrophy in coeliac disease

AIM: To investigate the association of FAS gene polymorphism with coeliac disease (CD) development.

METHODS: FAS-G670A gene polymorphism, located in a gamma interferon activation site, was studied in 146 unrelated CD patients and 203 healthy ethnically matched controls. The restriction fragment length polymorphism (RFLP) method was used to identify FAS-G670A gene polymorphism.

RESULTS: No significant difference was found in genotype frequency between CD cases and controls. In controls, however, the frequency of the GG genotype was significantly higher in women (26.5%) than in men (12.8%) (OR = 2.44, 95%CI 1.15-5.20, P = 0.020) and it was also higher in men with CD than controls (OR = 2.60, 95%CI 0.96-7.05, P = 0.061). The GG genotype frequency was significantly higher in patients with most severe villous atrophy (Marsh IIIc lesions) (OR = 3.74, 95%CI 1.19-11.82, P = 0.025). A significantly less proportion of men suffered from Marsh IIIc lesions than women (OR = 0.20, 95%CI 0.06-0.68, P = 0.01). The risk of having severe villous atrophy increased with the additive effect of the G allele in women (P = 0.027 for trend, age and gender adjusted).

CONCLUSION: FAS-G670A gene polymorphism is associated with the severity of villous atrophy in CD. Female gender is also associated with the severity of villous atrophy.

Gliadin and tissue transglutaminase complexes in normal and coeliac duodenal mucosa

Tissue transglutaminase (tTG) seems to be the target self-antigen for endomysial antibodies in coeliac disease (CD) and to catalyse the critical deamidation of gliadin which strengthens its recognition by HLA-restricted gut-derived T cells. To date, it has not been demonstrated whether gliadin is cross-linked to tTG within the gut wall, a phenomenon known to occur in vitro. We therefore investigated the putative presence of tTG and gliadin complexes directly in duodenal mucosa. The immunoprecipitation and Western blotting experiments were performed on mucosal biopsies obtained from untreated, treated CD patients and biopsied controls, by using either anti-tTG or anti-gliadin antibodies, in both denaturating/reducing or nondenaturating/nonreducing conditions. A subset of experiments was performed by using anti-tTG antibodies purified by affinity chromatography from sera of untreated coeliac patients. The localization of tTG and gliadin was studied by immunofluorescence at confocal laser microscopy on seriate sections of diseased and normal duodenal mucosa by using the same antibodies of the coimmunoprecipitation section. The amounts of tTG and gliadin coimmunoprecipitated with anti-tTG monoclonal antibody in untreated CD mucosa were significantly increased compared to those of the other two groups. When performing the experiments in nondenaturating/nonreducing conditions, a high molecular weight band formed by both molecules, was evidenciated. Also the anti-tTG antibodies purified from patients' sera turned out to be able to coimmunoprecipitate the two molecules. The analysis by confocal microscopy showed that tTG colocalizes with gliadin at the epithelial and subepithelial levels in active CD, and only in the lamina propria of the villi in normal mucosa. Our findings firstly demonstrated that gliadin was directly bound to tTG in duodenal mucosa of coeliacs and controls, and the ability of circulating tTG-autoantibodies to recognize and immunoprecipitate the tTG-gliadin complexes.

IL12B and IRF1 gene polymorphisms and susceptibility to celiac disease

Celiac disease (CD) is a common gastro-intestinal disorder resulting from permanent intolerance to wheat gliadins and related proteins in rye and barley. In addition to the strong genetic association with HLA-DQ2 and HLA-DQ8, a genetic region on chromosomes 5 (CELIAC2) has been identified that harbours a susceptibility gene for CD. The gene(s) responsible for this association, however, remains to be identified. In the present study we evaluated polymorphisms in the genes encoding interleukin-12 p40 (IL12B) and interferon regulatory factor 1 (IRF1). Both genes are located in the celiac2 region, and have key roles in inducing interferon (IFN)-gamma secreting T helper 1 (Th1) cells, one of the immunological hallmarks of CD. The frequencies of a TaqI gene polymorphism in the 3' UTR of IL12B and a HinfI gene polymorphism in the 3' UTR of IRF1 were studied in 258 Dutch CD patients and 237 ethnically matched healthy controls. The transmission of the polymorphic variants from parents to affected child was determined in 123 families with at least one affected child. The frequencies of the IL12B TaqI gene polymorphism and the IRF1 HinfI gene polymorphism did not differ significantly between patients and controls. In addition, in the family study, no deviation from the expected transmission from parents to affected child of any of the polymorphic variants was found. The IL12B TaqI and the IRF1 HinfI gene polymorphisms do not appear to be involved in susceptibility to CD. Further studies on the factors that drive the Th1 immunopathology in CD are required.

Pediatric celiac disease: clinicopathologic and genetic aspects

Evaluation for celiac disease (CD), an autoimmune enteropathy triggered by grain proteins in wheat, barley, rye, and possibly oats, is a common indication for pediatric endoscopy and biopsy. Duodenal or jejunal biopsy remains key for the initial diagnosis of CD. Small intestinal pathology may be diffuse or focal in CD, and histologic findings are nonspecific and must be interpreted in conjunction with clinical and serologic findings. A standardized grading system for CD biopsies is recommended. This review article summarizes the epidemiology, clinical manifestations, genetics, pathogenesis, and serologic and histologic findings of CD. Clinical management of CD and general handling of small intestinal biopsies are also addressed.

Interleukin 15: a key to disrupted intraepithelial lymphocyte homeostasis and lymphomagenesis in celiac disease

BACKGROUND & AIMS

The mechanism of intraepithelial lymphocyte hyperplasia, a hallmark of celiac disease, is unknown. We have investigated the role of epithelium-derived interleukin (IL)-15 in the alterations of epithelial homeostasis in refractory celiac sprue, a privileged situation to study the first step of lymphoid transformation and the contribution of intraepithelial lymphocytes to villous atrophy in celiac disease.

METHODS

IL-15 expression was assessed in biopsy specimens and isolated enterocytes by combining immunohistochemistry, flow cytometry, and real-time quantitative polymerase chain reaction. The ability of IL-15 to induce growth and survival of clonal intraepithelial lymphocytes lacking surface CD3 and to induce their cytotoxicity and secretion of interferon gamma was tested using soluble IL-15 and coculture in the presence of epithelial cell lines expressing membrane IL-15.

RESULTS

IL-15 was massively overexpressed not only in lamina propria but also in the intestinal epithelium of patients with active celiac disease and refractory celiac sprue. IL-15 was not secreted but delivered at the surface of enterocytes. IL-15 specifically induced the expansion and survival of the clonal abnormal intraepithelial lymphocytes that characterize refractory celiac sprue and triggered their secretion of interferon gamma and their cytotoxicity against intestinal epithelial cells. Comparable activating signals could be delivered by IL-15 expressed at the membrane of the T84 enterocyte cell line.

CONCLUSIONS

These data provide strong evidence that uncontrolled overexpression of IL-15 in refractory celiac sprue perpetuates epithelial damage and promotes the emergence of T-cell clonal proliferations. Blocking IL-15 might prove useful to treat this severe complication of celiac disease.

Enhanced expression of interferon regulatory factor-1 in the mucosa of children with celiac disease

Celiac disease (CD) is an enteropathy characterized by a Th1-type immune response to the dietary gluten. The transcriptional mechanisms or factors that control Th1 cell development in this condition remain to be elucidated. The aim of this study was to analyze in CD the expression of interferon (IFN) regulatory factor (IRF)-1, a transcription factor that regulates the differentiation and function of Th1 cells. Duodenal biopsies were taken from children with untreated CD and control children, and analyzed for IRF-1 by Southern blotting of reverse-transcriptase PCR products and Western blotting. IRF-1 DNA-binding activity was assessed by electrophoretic shift mobility assay. The effect of gliadin stimulation on IRF-1 induction was investigated in an ex vivo organ culture of treated CD biopsies. Enhanced IRF-1 was seen in untreated CD in comparison with controls. This was evident at both the RNA and protein level. Furthermore, untreated CD samples exhibited stronger nuclear accumulation and DNA-binding activity of IRF-1 than controls. In contrast, IRF-2, a transcriptional repressor that binds the same DNA element and competes with IRF-1, was expressed at the same level in nuclear proteins extracted from both untreated CD and control patients. In explant cultures of treated CD biopsies, gliadin enhanced both IRF-1 RNA and protein. This effect was prevented by a neutralizing IFN-gamma antibody. Furthermore, stimulation of normal duodenal biopsies with IFN-gamma enhanced IRF-1. These data indicate that IRF-1 is a hallmark of the gliadin-mediated inflammation in CD and suggest that IFN-gamma/IRF-1 signaling pathway can play a key role in maintaining and expanding the local Th1 inflammatory response in this disease.

Intestinal T-cell responses to high-molecular-weight glutenins in celiac disease

BACKGROUND & AIMS

The chronic, small intestinal inflammation that defines celiac disease is initiated by a HLA-DQ2 restricted T-cell response to ingested gluten peptides after their in vivo deamidation by tissue transglutaminase (TG2). To date, celiac disease can only be treated by a lifelong abstinence from foods that contain wheat, rye, or barley; better therapeutic options are hence needed. An attractive target would be to identify nontoxic wheat cultivars or components thereof with intact baking qualities. Because these qualities are mainly determined by the high molecular weight (HMW) glutenin proteins of gluten, it is critical to know if these proteins are toxic or, more specifically, if they will trigger the activation of T cells in the celiac lesion.

METHODS

Different, highly purified HMW glutenins were isolated from wheat cultivars or expressed as recombinant proteins. The proteins were first tested for recognition by a large panel of gluten-specific T-cell lines established from celiac lesions and then applied during ex vivo challenges of celiac biopsies to allow for a direct identification of HMW specific T cells.

RESULTS

Intestinal T-cell responses to TG2-deamidated HMW glutenins but not the corresponding native proteins were detectable in 9 of the 22 adult and childhood celiac disease patients tested.

CONCLUSIONS

T cells within celiac lesions frequently recognize deamidated HMW glutenin proteins. This finding questions the possibility of implementing these proteins in novel food items destined to be nontoxic for celiac disease patients.

Plasma cytokine profiles in patients with celiac disease and selective IgA deficiency

Celiac disease (CD) and selective IgA deficiency (IgAD) are frequently associated, and share the same genetic background. The aim of the present study was to evaluate both Type 1 and 2 plasma cytokine levels in CD and in CD-IgAD. IL-2, TNF-alpha, IL-10, IL-4 and IL-13 plasma levels were measured both at diagnosis and after a gluten-free diet (GFD) in 32 CD patients, in 27 CD-IgAD patients and in 30 healthy controls. IFN-gamma levels were significantly higher in CD and CD-IgAD than in controls, TNF-alpha displayed significantly higher levels in CD-IgAD when compared both with controls and with CD, and IL-2 was in CD-IgAD significantly increased respect to controls. Kinetics of the Type 1 cytokine plasma levels did not show a clear relationship with the GFD in both groups of CD patients, and particularly in those with IgAD. IL-4 and IL-13, both at diagnosis and after a GFD, were not significantly different in controls and in celiac patients (with and without IgAD). IL-10, whose production is stimulated by the TNF-alpha, had significantly higher plasma levels in CD-IgAD, but not in CD patients, with a significant decrease after a GFD. CD and especially CD-IgAD patients display persistently higher pro-inflammatory cytokine levels, suggesting a persistent state of activation of pro-phlogistic signals in CD, particularly when IgAD coexists. Serial measurement of serum IL-10 may be an adjunctive evaluating criterion in the follow-up of CD-IgAD patients.

Human small-intestinal epithelium contains functional natural killer lymphocytes

BACKGROUND & AIMS

CD3(-) non-T lymphocytes constitute the second most abundant lymphoid subset in the human small-bowel epithelium, and these CD3(-) intraepithelial lymphocytes are virtually absent in active celiac disease. Phenotypically, they resemble natural killer cells and have been termed natural killer-like intraepithelial lymphocytes. Because of the limited availability of appropriate human samples, functional studies have not yet been reported, and it is not yet clear whether these are true natural killer cells.

METHODS

We used magnetic bead-based purification and flow cytometry to study several aspects of normal human small-bowel natural killer-like intraepithelial lymphocytes: intracellular cytokine content (basally and after activation); ability to lyse natural killer-sensitive K562 target cells; and expression of perforins, Fas ligand, and other functional markers.

RESULTS

CD3(-) intraepithelial lymphocytes cultured in interleukin-2 showed a higher lymphokine-activated killer activity than CD3(+) intraepithelial lymphocytes (48%-83% lysis exerted by CD3(-) intraepithelial lymphocytes at an effector-target cell ratio of 2:1 vs. 8%-18% by CD3(+) intraepithelial lymphocytes). Perforin content correlated with this lytic potential (75% +/- 4% in CD3(-) vs. 5% +/- 4% in CD3(+) intraepithelial lymphocytes). Both CD3(-) and CD3(+) cells displayed a type I cytokine profile (interferon-gamma > tumor necrosis factor-alpha > interleukin-2; undetectable interleukin-4 and interleukin-10). In addition to their activated phenotype, subsets of natural killer-like intraepithelial lymphocytes expressed CD8alphaalpha and intracellular CD3epsilon chain, showing the existence of heterogeneity within this cell lineage.

CONCLUSIONS

This is the first demonstration of functional natural killer cells within the human gut epithelium. These cells might play an important role in innate mucosal immunity (host defense and tumor surveillance) and tolerance.

Modulation of cytokine release from colonic explants by bacterial antigens in inflammatory bowel disease

The intestinal flora play an important role in experimental colitis and inflammatory bowel disease (IBD). Using colonic explant cultures from 132 IBD and control subjects, we examined tumour necrosis factor-alpha (TNF-alpha), interleukin (IL)-1 and interleukin-1 receptor antagonist (IL-1RA) production in vitro in response to bacterial activators. Unstimulated TNF-alpha release was increased significantly in rectal biopsies from involved IBD tissue, correlating with inflammation severity. Whereas lipopolysaccharide (LPS) only moderately stimulated TNF-alpha production from inflamed tissue, pokeweed mitogen (PWM) induced its release in all groups, with a stronger response in involved IBD tissue. Superantigen staphylococcal enterotoxin A (SEA) had a similar, but weaker effect. SEB was observed to be the strongest inducer of TNF-alpha for all groups, again with a more marked response in inflamed tissue. Stimulated release of IL-1 was considerably less than for TNF-alpha. The superantigens' superior potency over LPS was not as marked for IL-1 as it was for TNF-alpha. In addition to IL-1, IL-1RA release was also triggered by the bacterial products. The net effect of activation on the IL-1RA/IL-1 ratio was relatively modest. Release of the proinflammatory cytokines TNF-alpha and IL-1, as well as that of the anti-inflammatory cytokine IL-1RA was increased by incubation of colonic tissue with bacterial factors. TNF-alpha production and release was increased significantly in involved colonic explants from IBD. SEB was even capable of inducing TNF-alpha release from uninvolved colonic tissue.

Cytokines and adhesion molecules in duodenal mucosa of children with delayed-type food allergy

OBJECTIVES

The aim was to investigate the expression of cytokines, adhesion molecules, and activation and proliferation markers in duodenal biopsies from children with delayed-type food allergy (FA).

METHODS

Seven children with untreated FA (uFA), seven children with treated FA (tFA) to cow milk and/or cereals, and five normal controls furnished duodenal biopsy specimens. Additionally, five pediatric patients with celiac disease were included, serving exclusively as positive controls for in situ hybridization. Interferon-gamma (IFN-gamma), interleukin-4 (IL-4), adhesion molecules, and activation markers were detected by immunohistochemistry, and expression of IFN-gamma and IL-4 messenger RNA was revealed by in situ hybridization.

RESULTS

uFA patients had a higher density of IFN-gamma positive cells in the lamina propria than did tFA patients and controls (P = 0.053 and P = 0.018). Moreover, the uFA patients exhibited a higher proportion of crypt cells in mitosis than did tFA patients (P = 0.026), and stronger staining of HLA-DR in the crypts and increased density of gammadelta-T cell receptor-positive intraepithelial lymphocytes than did controls (P = 0.048 and P = 0.010). The densities of alpha(4)beta(7) positive cells in the lamina propria tended to be higher in controls than in uFA or tFA patients (P = 0.106, P = 0.073). Expression of IL-4 mRNA was significantly higher in celiac patients than in the other study groups (uFA P = 0.006, tFA P = 0.010; controls P = 0.029), and celiac patients showed higher expression of IFN-gamma mRNA than did tFA patients or controls (P = 0.017 and P = 0.016).

CONCLUSIONS

As expected, Th1 dominance was present in the lamina propria of children with delayed-type FA. It may cause activation of epithelial cells and increase their turnover.

Association of -1087 IL10 and -308 TNFA gene polymorphisms with serological markers of coeliac disease

Coeliac disease (CD) is known to have a strong genetic background. We analyzed the association between serological markers of CD and the -1087 IL10 and -308 TNFA gene polymorphisms in Swedish patients. A higher frequency of the TNF2 allele was present in the patients compared with the controls (p < 0.0001). The frequency of the AA genotype of the IL10 gene in the patients was unexpectedly higher in comparison with the controls (p < 0.05). The levels of IgA anti-endomysium and antitissue transglutaminase antibodies were associated with IL10 but not with TNFA genotype. The patients with the AA or GG -1087 IL10 genotypes had significantly lower levels of antibodies in comparison with those with the AG genotype (p < 0.05 to p < 0.0005). However, when divided according to potential level of IL-10 production, the group of potentially high IL-10 producers among the CD patients demonstrated significantly lower levels of antitissue transglutaminase antibodies compared to potentially low IL-10 producers (p = 0.01). Our results show a relationship between the levels of IgA antibodies involved in CD with the IL10 genotypes. This suggests a possible involvement of IL-10 in the development of the disease.

Nuclear factor kappa B is activated in small intestinal mucosa of celiac patients

NF-kappa B regulates inflammatory and immune response by increasing the expression of specific genes. In celiac disease proinflammatory cytokines, adhesion molecules, and enzymes whose gene expression is known to be regulated by NF-kappa B are involved. This study investigated the activation of NF-kappa B in inflamed mucosa from patients with untreated celiac disease. Biopsy specimens from control, untreated, and treated patients were subjected to molecular biology analysis. NF-kappa B activation was evaluated by electrophoretic mobility shift assay. NF-kappa B related subunit protein level, and inducible nitric oxide synthase and cyclo-oxygenase 2 protein expression was analyzed by western blot. Both NF-kappa B/DNA binding activity and p50/p65 nuclear levels were higher in biopsy specimens from untreated patients than in those from treated patients and controls. The degradation of I kappa B beta in the cytosol and the reappearance in the nucleus indicated a persistent NF-kappa B activation in celiac disease. NF-kappa B activity was maintained in cultured biopsy specimens up to 6 h and decreased at 24 h, and then the addition of peptic-tryptic digest of gliadin caused the recovery of NF-kappa B activity at 6 h. NF-kappa B/DNA binding activity was correlated with inducible nitric oxide synthase and cyclo-oxygenase-2 protein expression. These results show for the first time that NF-kappa B is activated in the inflamed mucosa of celiac patients and suggest that it may represent a molecular target for the modulation of inflammatory response in celiac disease.

Constitutive activation of the signal transducer and activator of transcription pathway in celiac disease lesions

The biological effects of interferon (IFN)-gamma rely mainly on the activity of the transcription factor signal transducer and activator of transcription (STAT) 1 and the intracellular levels of suppressor of cytokine signaling (SOCS)-1, a negative regulator that controls the amplitude and duration of STAT-1 activation. IFN-gamma is a key mediator of the immunopathology in celiac disease (CD, gluten-sensitive enteropathy). Thus we have investigated STAT-1 signaling and SOCS-1 expression in this condition. As expected, high local concentrations of IFN-gamma were invariably seen in duodenal biopsies from CD patients in comparison to controls. On the basis of immunohistochemistry, STAT-1 phosphorylation, nuclear localization, and DNA-binding activity, STAT-1 activation was consistently more pronounced in CD compared with controls. Despite samples from CD patients containing abundant SOCS-1 mRNA, SOCS-1 protein was expressed at the same level in CD patients and controls. In explant cultures of CD biopsies, gliadin induced the activation of STAT-1 but not SOCS-1. Furthermore, inhibition of STAT-1 prevented the gliadin-mediated induction of ICAM-1 and B7-2. These data suggest that persistent STAT-1 activation can contribute to maintaining and expanding the local inflammatory response in CD.

Genetic susceptibility to food allergy is linked to differential TH2-TH1 responses in C3H/HeJ and BALB/c mice

BACKGROUND

Although food allergy is a serious health problem in westernized countries, factors influencing the development of food allergy are largely unknown. Appropriate murine models of food allergy would be useful in understanding the mechanisms underlying food allergy in human subjects.

OBJECTIVE

We sought to determine the susceptibility of different strains of mice to food hypersensitivity.

METHODS

C3H/HeJ and BALB/c mice were sensitized to cow's milk (CM) or peanut by means of intragastric administration, with cholera toxin as a mucosal adjuvant. Mice were then challenged with CM or peanut. Antigen-specific IgE levels, anaphylactic symptoms, plasma histamine levels, and splenocyte cytokine profiles of these 2 strains were compared.

RESULTS

CM-specific IgE levels were significantly increased only in the C3H/HeJ strain, 87% of which exhibited systemic anaphylactic reactions accompanied by significantly increased plasma histamine levels in response to challenge. BALB/c mice exhibited no significant CM-specific IgE response, increased plasma histamine levels, or anaphylactic symptoms. After peanut challenge, 100% of peanut-sensitized C3H/HeJ mice exhibited high levels of peanut-specific IgE and anaphylactic symptoms. In contrast, no hypersensitivity reactions were detected in BALB/c mice, despite the presence of significant serum peanut-specific IgE levels. Splenocytes from CM- and peanut-sensitized C3H/HeJ mice exhibited significantly increased IL-4 and IL-10 secretion, whereas splenocytes from BALB/c mice exhibited significantly increased IFN-gamma secretion.

CONCLUSION

Induction of food-induced hypersensitivity reactions in mice is strain dependent, with C3H/HeJ mice being susceptible and BALB/c mice being resistant. This strain-dependent susceptibility to food allergy is associated with differential T(H)2-T(H)1 responses after intragastric food allergen sensitization.

Celiac disease: a model autoimmune disease with gene therapy applications

Gene therapy (GT) is still at the 'experimental' stage and some recent setbacks have cooled the potential use of this therapeutic tool even in life-threatening conditions. However, this therapeutic approach has a potential, which is not limited to disease for which we have not other option. There are increasing evidence that GT will be soon used in diseases that are not life threatening. One group of diseases that can benefit from GT is the autoimmune one. Several experimental animal models have indicated the efficacy (proof of principle) of GT. In the present review, we have addressed the possibility that even extremely benign autoimmune-like diseases such as Celiac Disease (CD) might one day profit from this type of therapy. We further point that in conditions such as CD, where the trigger is well known and the pathogenic cascade is relatively well defined, a situation not common in autoimmunity, we can even have a better situation where to explore and use GT to control disease initiation and progression. Once the risks that are still intrinsic to GT will have been reduced the therapeutic options we outline in the present review might not appear too far from reality.

Engineered recombinant peanut protein and heat-killed Listeria monocytogenes coadministration protects against peanut-induced anaphylaxis in a murine model

Peanut allergy (PNA) is the major cause of fatal and near-fatal anaphylactic reactions to foods. Traditional immunotherapy using peanut (PN) protein is not an option for PNA therapy because of the high incidence of adverse reactions. We investigated the effects of s.c. injections of engineered (modified) recombinant PN proteins and heat-killed Listeria monocytogenes (HKLM) as an adjuvant on anaphylactic reactions in a mouse model of PN allergy. PN-allergic C3H/HeJ mice were treated s.c. with a mixture of the three major PN allergens and HKLM (modified (m)Ara h 1-3 plus HKLM). The effects on anaphylactic reactions following PN challenge and the association with Ab levels and cytokine profiles were determined. Although all mice in the sham-treated groups exhibited anaphylactic symptoms with a median symptom score of 3, only 31% of mice in the mAra h 1-3 plus HKLM group developed mild anaphylaxis, with a low median symptom score of 0.5. Alterations in core body temperature, bronchial constriction, plasma histamine, and PN-specific IgE levels were all significantly reduced. This protective effect was markedly more potent than in the mAra h 1-3 protein alone-treated group. HKLM alone did not have any protective effect. Reduced IL-5 and IL-13, and increased IFN-gamma levels were observed only in splenocytes cultures from mAra h 1-3 plus HKLM-treated mice. These results show that immunotherapy with modified PN proteins and HKLM is effective for treating PN allergy in this model, and may be a potential approach for treating PNA.

Association between migraine and Celiac disease: results from a preliminary case-control and therapeutic study

OBJECTIVES

Subclinical celiac disease (CD) has been associated with various neurological disorders, the most common being neuropathy and cerebellar ataxia. The aims of the present study were to assess the following: 1) the prevalence of CD in patients affected by migraine; 2) whether there are regional cerebral blood flow abnormalities in migraine patients with CD compared to migraine patients without CD; and 3) the effects of a gluten free diet in migraine patients with CD.

METHODS

A total of 90 patients affected by idiopathic migraine were enrolled, and 236 blood donors were used as controls. Serum IgG antitransglutaminase (TgA) and IgA antiendomysial (EmA) were measured. In positive cases, diagnosis was confirmed endoscopically. A gluten free diet was started in the patients diagnosed with CD, who were followed for 6 months. A single photon emission CT brain study was performed before and after a gluten free diet.

RESULTS

Four of 90 (4.4%; 95% CI = 1.2-11.0) migraine patients were found to have CD compared with 0.4% (95% CI = 0.01-2.3) blood donor controls (p < 0.05). During the 6 months of gluten free diet, one of the four patients had no migraine attacks, and the remaining three patients experienced an improvement in frequency, duration, and intensity of migraine. Single photon emission CT studies showed a regional baseline reduction in brain tracer uptake in all four patients. Such reduction in uptake completely resolved at follow-up.

CONCLUSIONS

Our results suggest that a significant proportion of patients with migraine may have CD, and that a gluten free diet may lead to a improvement in the migraine in these patients.

Celiac disease association with CD8+ T cell responses: identification of a novel gliadin-derived HLA-A2-restricted epitope

One of the diagnostic hallmarks of the histological lesions associated with celiac disease is the extensive infiltration of the small intestinal epithelium by CD8(+) T cells of unknown Ag specificity. In this study, we report recognition of the gliadin-derived peptide (A-gliadin 123-132) by CD8(+) T lymphocytes from celiac patients. A-gliadin 123-132-specific IFN-gamma production and cytotoxic activity were detected in PBMCs derived from patients on gluten-free diet, but not from either celiac patients on gluten-containing diet or healthy controls. In contrast, A-gliadin 123-132-specific cells were isolated from small intestine biopsies of patients on either gluten-free or gluten-containing diets. Short-term T cell lines derived from the small intestinal mucosa and specific for the 123-132 epitope recognized human APC pulsed with either whole recombinant alpha-gliadin or a partial pepsin-trypsin gliadin digest. Finally, we speculate on a possible mechanism leading to processing and presentation of class I-restricted gliadin-derived epitopes in celiac disease patients.

Neutrophil CD11b, L-selectin and Fc IgA receptors in patients with dermatitis herpetiformis

BACKGROUND

The skin lesions found in patients with dermatitis herpetiformis (DH) are characterized by the presence of neutrophils at the dermal papillary tips in areas where the diagnostic cutaneous IgA deposits are found. Although the presence of the skin lesions of DH is known to be associated with gluten-sensitive enteropathy, the mechanisms that control the development of skin lesions are not known.

OBJECTIVES

To determine if circulating neutrophils from patients with DH have evidence of priming as shown by increased expression of CD11b, decreased expression of L-selectin and increased function of neutrophil Fc IgA receptor.

METHODS

Neutrophils from 12 normal subjects and 10 DH patients with active, ongoing disease and 14 DH patients with quiescent disease activity were examined by fluorescence-activated cell sorter for expression of cell surface CD11b, L-selectin expression, Fc IgA expression (CD89) and for the function of the Fc IgA receptor by determining the binding capacity of neutrophils for monoclonal human IgA.

RESULTS

Neutrophils from patients with active, ongoing DH had increased expression of CD11b when compared with patients with inactive DH or normal subjects [mean net geometric mean channel fluorescence (GMCF): active DH, 403.3; inactive DH, 237.8; normal subjects, 290.5; P < 0.05]. L-selectin expression in both groups of DH patients was significantly lower than that seen in normal subjects (mean net GMCF: active DH, 363.2; inactive DH, 375.2; normal subjects, 432.7; P < 0.05). No difference in CD89 expression was seen in any of the groups; however, the function of Fc IgA receptor was increased in patients with active DH when compared with patients with inactive DH and normal subjects.

CONCLUSIONS

Neutrophils from patients with active, ongoing DH show an increased expression of CD11b, decreased expression of L-selectin and increased ability to bind IgA, consistent with a pattern of priming of the neutrophils. This priming may occur in the gut as a result of the ongoing mucosal immune response that is present in patients with DH on a gluten-containing diet and may predispose neutrophils to localize in the skin of patients with DH.

Interferon-gamma-secreting T cells localize to the epithelium in coeliac disease

Increased levels of interferon-gamma (IFN-gamma) transcripts have previously been found in duodenal biopsy specimens from patients with untreated coeliac disease (CD). Such samples and duodenal control mucosa were therefore studied to locate and phenotype cells spontaneously secreting IFN-gamma. Specimens were collected from consecutively recruited patients with untreated (seven), treated (four) or refractory (three) CD and from five histologically normal controls. Morphological and immunohistochemical examinations were performed, and epithelial and lamina propria cell suspensions were prepared from parallel samples. Unstimulated viable cells secreting IFN-gamma were identified and phenotyped with a new fluorescence-activated cell sorter-based assay, and IFN-gamma messenger RNA (mRNA) was analysed in snap-frozen aliquots of the same suspensions. Untreated CD cases had the highest fraction of IFN-gamma+ cells in the epithelial compartment (median 2.6%, range 1.6-6.2%) and, less strikingly, in the lamina propria compartment (1.6%, range 0.3-3.6%), followed by refractory (1.4%, 1.0-1.9%; and 0.3%, 0.0-1.2%) and treated (0.8%, 0.5-0.9%; and 0.7%, 0.2-1.1%) disease and finally the controls (0.5%, 0.3-0.9%; and 0.2%, 0.1-0.7%). IFN-gamma mRNA data supported these findings. IFN-gamma+ intraepithelial lymphocytes were mostly CD3+ and CD8+, whereas many positive lamina propria cells were CD8-. We conclude that isolated T cells spontaneously secreting IFN-gamma localize preferentially in the epithelium of patients with classical and refractory CD.

T cell activation causes diarrhea by increasing intestinal permeability and inhibiting epithelial Na+/K+-ATPase

Inflammatory bowel disease (IBD) is associated with mucosal T cell activation and diarrhea. We found that T cell activation with anti-CD3 mAb induces profound diarrhea in mice. Diarrhea was quantified by intestinal weight-to-length (wt/l) ratios, mucosal Na(+)/K(+)-ATPase activity was determined and ion transport changes were measured in Ussing chambers. Anti-CD3 mAb increased jejunal wt/l ratios by more than 50% at 3 hours, returning to base line after 6 hours. Fluid accumulation was significantly reduced in TNF receptor-1 (TNFR-1(-/-)), but not IFN-gamma knockout mice. Anti-CD3 mAb decreased mucosal Na(+)/K(+)-ATPase activity, which was blocked by anti-TNF mAb and occurred to a lesser degree in TNFR-1(-/-) mice. Neither alpha nor beta subunits of Na(+)/K(+)-ATPase decreased in abundance at 3 hours. Intestinal tissue from anti-CD3-treated mice exhibited increased permeability to mannitol at 1 hour and decreases in electroneutral Na(+) absorption, Na(+)-dependent glucose absorption, and cAMP-stimulated anion secretion at 3 hours. Furthermore, enteral fluid accumulation was observed in CFTR(-/-) mice, indicating a minor role of active anion secretion. These data suggest that diarrhea in IBD is due to TNF-mediated malabsorption rather than to secretory processes. T cell activation induces luminal fluid accumulation by increasing mucosal permeability and reducing epithelial Na(+)/K(+)-ATPase activity leading to decreased intestinal Na(+) and water absorption.

Transforming growth factor-beta (TGF-beta) and tissue transglutaminase expression in the small intestine in children with coeliac disease

The production of cytokines from T cells and macrophages is of potential importance for the histological changes apparent in coeliac disease (CoD). Small intestinal biopsy specimens from children with CoD and disease control subjects were investigated for their content of cytokines and tissue transglutaminase (tTG). The transforming growth factor-beta1 (TGF-beta1) expression was increased in the lamina propria of children with villous atrophy. In contrast, TGF-beta3 was expressed at a higher level in the epithelium and the lamina propria of the disease control subjects. The tTG expression was increased in the small intestine of CoD patients as compared with that in subjects. Interleukin-4 (IL-4) was detected in the lamina propria of both CoD patients and controls, and some of the investigated biopsy specimens also showed IL-4 expression in the epithelium. We conclude that children with active CoD could have an altered expression of TGF-beta and tTG in the small intestine and that a disturbed regulation of TGF-beta may be of importance in the immune pathogenesis of CoD.

Polymorphism of the inducible nitric oxide synthase gene in celiac disease

The aim of this study was to investigate the possible association between the inducible nitric oxide synthase (NOS2) gene promoter polymorphism, CCTTTn microsatellite, with celiac disease susceptibility. We carried out a familial study in which 53 Spanish families were genotyped by a polymerase chain reaction (PCR)-based method combined with fluorescent technology. A transmission disequilibrium test was performed to investigate the transmission pattern of the different CCTTTn alleles from parents to affected offspring. The test did not reach any statistically significant difference because none of the CCTTTn repeats was shown to be significantly transmitted to the affected siblings. Our data suggest that the CCTTTn pentanucleotide microsatellite in the NOS2 gene promoter does not play a major role in celiac disease development.

Serum soluble interleukin-2 receptor, interleukin-6, and tumor necrosis factor-alpha levels in children with celiac disease: response to treatment

OBJECTIVES

T-cell mediated immune response to dietary gluten and cytokines release are important for the enteropathy seen in celiac disease. We investigated the serum levels of soluble interleukin-2 receptor, interleukin-6, and tumor necrosis factor-alpha in celiac children before and after gluten exclusion.

METHODS

Cytokine levels were determined using enzyme immunoassay in serum from 12 untreated celiac patients, 16 treated celiac patients on a gluten-free diet for at least two years, and from 26 control children. Eight of 12 untreated patients were also investigated at 6 and 12 months after gluten exclusion. Serum IgA antiendomysium antibodies were also assayed by indirect immunofluorescence.

RESULTS

Soluble interleukin-2 receptor and interleukin-6 levels were significantly increased in untreated celiac patients compared with treated and control children. There was no difference in the tumor necrosis factor-alpha levels between the groups. Soluble interleukin-2 receptor levels were the only ones significantly decreased at 12 months after gluten exclusion. However, soluble interleukin-2 receptor and interleukin-6 levels at 12 months were significantly higher compared with controls. Antiendomysium antibodies had a diagnostic sensitivity of 100% and the titers decreased significantly after 12 months of gluten exclusion. A significant positive correlation was found between antiendomysium antibody titers with both soluble interleukin-2 receptor and interleukin-6 values.

CONCLUSIONS

The serum soluble interleukin-2 receptor and interleukin-6 levels may be used as a noninvasive measure of celiac disease activity and response to treatment.

Paradoxical coexpression of proinflammatory and down-regulatory cytokines in intestinal T cells in childhood celiac disease

BACKGROUND & AIMS

Specific T-lymphocyte reactions are central in the pathogenesis of celiac disease, an inflammatory small-bowel enteropathy caused by a permanent intolerance to gluten. To delineate local T-lymphocyte responses to gluten, the cytokine expression in jejunal T lymphocytes of pediatric celiac patients with active disease, i.e., untreated and gluten-challenged celiac patients, was determined and compared with that of treated, symptom-free celiac patients and controls.

METHODS

Biopsy samples were collected from celiac patients and controls. Intraepithelial and lamina propria T lymphocytes were isolated separately, and the cytokine messenger RNA levels were determined by using quantitative real-time reverse-transcription polymerase chain reaction. Interferon (IFN)-gamma and interleukin (IL)-10 were determined at the protein level by immunohistochemistry.

RESULTS

Active celiac disease was characterized by distortions in cytokine expression by T lymphocytes, with highly significant increases of IFN-gamma and IL-10 but no concomitant increases in tumor necrosis factor alpha, transforming growth factor beta1, or IL-2 and no induction of IL-4. A marked shift of IFN-gamma and IL-10 production from the lamina propria to the epithelium was characteristic of active celiac disease, and as many as one fourth of the intraepithelial lymphocytes expressed IFN-gamma. Intraepithelial T lymphocytes in treated, symptom-free celiac patients still had increased IFN-gamma levels compared with controls.

CONCLUSIONS

In celiac patients, gluten intake seems to cause an overreaction in intraepithelial T lymphocytes, with uncontrolled production of IFN-gamma and IL-10. This may cause both recruitment of intraepithelial lymphocytes and a leaky epithelium, leading to a vicious circle with amplified immune activity and establishment of intestinal lesions.

Coeliac disease: dissecting a complex inflammatory disorder

The disease mechanisms of complex inflammatory disorders are difficult to define because of extensive interactions between genetic and environmental factors. Coeliac disease is a typical complex inflammatory disorder, but this disease is unusual in that crucial genetic and environmental factors have been identified. This knowledge has allowed functional studies of the predisposing HLA molecules, the identification of antigenic epitopes and detailed studies of disease-relevant T cells in coeliac disease. This dissection of the pathogenic mechanisms of coeliac disease has uncovered principles that are relevant to other chronic inflammatory diseases.

Endocrinological disorders and celiac disease

Celiac disease is a permanent intolerance to dietary gluten. Its well known features are abdominal symptoms, malabsorption of nutrients, and small-bowel mucosal inflammation with villous atrophy, which recover on a gluten-free diet. Diagnosis is challenging in that patients often suffer from subtle, if any, symptoms. The risk of clinically silent celiac disease is increased in various autoimmune conditions. The endocrinologist, especially, should maintain high suspicion and alertness to celiac disease, which is to be found in 2-5% of patients with insulin-dependent diabetes mellitus or autoimmune thyroid disease. Patients with multiple endocrine disorders, Addison's disease, alopecia, or hypophysitis may also have concomitant celiac disease. Similar heredity and proneness to autoimmune conditions are considered to be explanations for these associations. A gluten-free diet is essential to prevent celiac complications such as anemia, osteoporosis, and infertility. The diet may also be beneficial in the treatment of the underlying endocrinological disease; prolonged gluten exposure may even contribute to the development of autoimmune diseases. The diagnosis of celiac disease requires endoscopic biopsy, but serological screening with antiendomysial and antitissue transglutaminase antibody assays is an easy method for preliminary case finding. Celiac disease will be increasingly detected provided the close association with autoimmune endocrinological diseases is recognized.

Basement membrane and connective tissue proteins in intestinal mucosa of patients with coeliac disease

AIMS

Gluten ingestion in coeliac disease is associated with alterations of the intestinal mucosa, especially the expansion of the lamina propria. Antiendomysium and antireticulin antibodies may result from interactions between gliadin and extracellular matrix components. By behaving as autoantigens, connective tissue proteins could initiate mucosal damage. This study evaluates changes in the distribution of laminin, type IV collagen, and fibronectin in the mucosa of patients with coeliac disease in an attempt to explain the alterations of mucosal morphology.

METHODS

Intestinal biopsies were obtained from patients with coeliac disease on admission and while on a gluten free diet. The distribution of type IV collagen, laminin, fibronectin, and alpha-smooth muscle actin was evaluated by immunofluorescence and by immunogold labelling and electron microscopy.

RESULTS

In patients with coeliac disease, the intensity of type IV collagen, laminin, and fibronectin immunofluorescent staining was decreased and less well defined than in controls, with frequent breaches in the basement membrane; fibronectin staining was weak in the distal third of the elongated crypts and absent under the flat surface. The distribution of smooth muscle fibre in the distal lamina propria of flat mucosae was altered. The distribution of these proteins was normal as assessed by immunoelectron microscopy.

CONCLUSIONS

The intensity of staining of some components of the basement membrane is decreased in coeliac disease and the distribution of smooth muscle fibres is altered. These changes may result from interactions between gliadin and components of the extracellular matrix and may play a role in the genesis of mucosal lesions and in the damage to the epithelium.

Monitoring of in vitro deamidation of gliadin peptic fragment by mass spectrometry may reflect one of the molecular mechanisms taking place in celiac disease development

Celiac disease, a chronic disorder of the small intestine, is caused by dietary gluten and is characterized by villous atrophy and local inflammation associated with infiltration of B and T lymphocytes and/or macrophages into the intestinal wall. In genetically predisposed individuals, the infiltrating cells are activated by gluten, gliadin and their proteolytic fragments and produce chemokines, cytokines and reactive radicals. The sequence of one of the macrophage-stimulatory gliadin peptic fragment was determined by mass spectrometry (MS) as VSFQQPQQQYPSSQ. The role of tissue transglutaminase (tTG) in innate immunity stimulation was studied by mass spectrometric monitoring of sequence changes in this active peptide. Two sites of glutamine deamidation in this peptide were localized by high-resolution scanning in MS/MS mode in an ion trap. A single deamidation in the parent peptide led to the complete loss of its stimulatory effect on macrophages.

Current understanding of gastrointestinal immunoregulation and its relation to food allergy

Tolerance to food antigens induced via the gut ("oral tolerance") appears to be a rather robust adaptive immune mechanism. However, the neonatal period is particularly critical in terms of mucosal defense, with regard to infections and priming for allergic disease. This is so because the intestinal barrier function provided by secretory antibodies, as well as the immunoregulatory network, is poorly developed for a variable period after birth. Notably, the postnatal development of mucosal immune homeostasis depends on the establishment of a normal commensal microbial flora and also on adequate timing and dose of dietary antigens when first introduced. In this context, breastfeeding appears to exert both shielding and positive regulatory effects. Altogether, the intestinal immune system normally seems rather fit for tolerance induction against innocuous antigens because most children with food allergy "outgrow" their problems, whereas airway allergy tends to persist.

Inflammatory cytokines in small intestinal mucosa of patients with potential coeliac disease

T helper cell type 1 (Th1) response to gluten has been implicated in the pathogenesis of coeliac disease (CD). To characterize immunological activation and mild inflammations leading to overt CD in potential coeliac patients, jejunal biopsies were obtained from family members of patients with CD or dermatitis herpetiformis (DH). Nine family members and one latent CD, eight CD patients and eight normal controls furnished jejunal biopsy specimens. Immunohistochemical staining of sections for interleukin-1alpha (IL-1alpha), IL-2, IL-4, interferon-gamma (IFN-gamma), tumour necrosis factor alpha (TNF-alpha), CD3, gammadelta-T cell receptor (gammadelta-TCR), and alphabeta-TCR was carried out with monoclonal antibodies. Further, expression of IL-4 and IFN-gamma messenger RNA was detected by radioactive in situ hybridization in these same samples. In lamina propria, CD patients and potential CD patients had higher densities of IL-2 (P = 0.028, P = 0.043), IL-4 (P = 0.021, P = 0.034) and IFN-gamma positive cells (P = 0.000, P = 0.009) than did controls. Moreover, CD patients showed a higher density of TNF-alpha positive cells (P = 0.012, P = 0.001) than the other two groups, and expression of IFN-gamma mRNA (P = 0.035) was higher in them than in the other two study groups. Additionally, higher densities of TNF-alpha and IFN-gamma positive cells occurred in potential CD patients with high gammadelta-TCR+ intraepithelial lymphocytes (IELs). Our findings support the hypothesis that lamina propria T cells and macrophages, through their secretion of cytokines, play a central role in the pathogenesis of coeliac disease. The inflammatory cytokines found in potential CD specimens strongly suggest that these inflammatory markers can be identified long before visible villous changes have occurred.

Successful infliximab treatment for steroid-refractory celiac disease: a case report

Celiac disease is a T cell-mediated enteropathy induced by gluten in genetically predisposed individuals. The majority of patients responds to a gluten-free diet but a small number do not. After the exclusion of gluten in the diet, ulcerative jejunititis, and an enteropathy-associated T-cell lymphoma, another treatment modalities, such as systemic steroids and immunosuppressives, may be necessary. This article reports the case of a 47-year-old white woman with immunoglobulin A deficiency. She was diagnosed with celiac disease with subtotal villous atrophy on jejunal biopsy together with positive antiendomysium and antigliadin immunoglobulin G antibodies. Despite close adherence to a gluten-free diet, her weight continued to decrease, she had diarrhea, and her distal duodenal histology showed no improvement. Some improvement in her symptoms was observed with cyclosporine and systemic steroids, but this was not sustained. Recent evidence has suggested that anti-tumor necrosis factor alpha antibodies have a role in the amelioration of an animal model of villous atrophy, and after careful consideration, she was treated with infliximab. There was a dramatic improvement in her weight, symptoms, and distal duodenal histology. The response has been maintained for 18 months while on azathioprine therapy. It is concluded that infliximab is an effective treatment that may be considered in a small number of patients with refractory celiac disease, resistant to other therapy.

Coeliac disease--all questions answered?

Gliadin specific T cells in the small intestines of coeliac disease patients use the disease associated human leukocyte antigen-DQ2 molecules in their antigen recognition. In an exciting interplay with tissue transglutaminase, the immune system recognises modified gliadin peptides and mounts a phlogistic response. Moreover, the role for autoimmune phenomena and the mechanism of breaking of immunological tolerance remain elusive.

Update on immunologic basis of celiac disease

During the past few years several seminal studies have greatly expanded our knowledge on celiac disease pathogenesis. This review focuses on aspects that have been most properly addressed and where substantial new information has been gathered include. Topics covered include (a) the identification of T-cell epitopes in gluten and the mechanisms of specific T-cell response in celiac disease small intestine; (b) the mechanisms of induction of mucosal lesion; and (c) the putative role of non-T-cell factors in driving mucosal response to gliadin. After discussing a brief history of the "quest for the cause of celiac disease," we examine the development of the typical celiac lesion (the crypt hyperplastic mucosal atrophy) as it generally unfolds: the increased entry of dietary antigens; the early changes, linked to specific components of the innate immunity rather than to its adaptive branch; the most thoroughly investigated subsequent response, involving a strong T-cell response and cytokines; and the factors responsible for enterocytes' death. The emerging pattern is that of a complex interaction of factors, although far from being completely understood, but fascinating as it opens an incredible window of knowledge on an autoimmune disorder whose environmental factor is known, whose autoantigen is known, whose autoantibodies are known: a truly unique situation in medicine.

The IL12B gene does not confer susceptibility to coeliac disease

Coeliac disease (CD) is a chronic inflammatory disorder where dietary gluten is not tolerated. In the lesion there are gluten reactive T cells predominantly secreting gamma-interferon. Both HLA and non-HLA genes contribute to CD susceptibility. Interleukin-12 (IL-12) regulates gamma-interferon production. The IL12B gene is located in a region (5q31.1-33.1) where there is evidence for linkage with CD. Allele 1 of an IL12B 3'UTR single-nucleotide polymorphism leads to increased expression of IL-12, and was recently implicated in susceptibility for type 1 diabetes (T1D). We found no evidence for association of allele 1 to CD by the transmission/disequilibrium test or case-control approach. No increased frequency was observed in patients belonging to families where the disease was linked to markers on chromosome 5q. Unlike T1D, allele 1 does not appear to confer susceptibility to CD.

Transglutaminases in disease

Transglutaminases (TGases) are enzymes that are widely used in many biological systems for generic tissue stabilization purposes. Mutations resulting in lost activity underlie several serious disorders. In addition, new evidence documents that they may also be aberrantly activated in tissues and cells and contribute to a variety of diseases, including neurodegenerative diseases such as Alzheimer's and Huntington's diseases. In these cases, the TGases appear to be a factor in the formation of inappropriate proteinaceous aggregates that may be cytotoxic. In other cases such as celiac disease, however, TGases are involved in the generation of autoantibodies. Further, in diseases such as progressive supranuclear palsy, Huntington's, Alzheimer's and Parkinson's diseases, the aberrant activation of TGases may be caused by oxidative stress and inflammation. This review will examine the role and activation of TGases in a variety of diseases.