Cytokine profile in coeliac disease

Human intestinal alphabeta IEL clones in celiac disease show reduced IL-10 synthesis and enhanced IL-2 production

Celiac disease is a gluten-induced T-cell mediated autoimmune process that results in the destruction of the intestinal mucosa and is associated with an expansion of CD8(+) CD103(+) TCRalphabeta intraepithelial lymphocytes (IELs) in the damaged epithelium. The role of this IEL population in the pathology is unknown. The aim of this work was to compare the cytokine profile and the cytotoxicity pattern from CD8(+) IEL clones isolated from celiac (CD) and non-celiac (NCD) biopsies. We report that the number of IL-10 producing CD clones was significantly lower (26%) than that obtained from the NCD sample (62%). Instead, IL-2 was produced by more CD (44%) than NCD clones (26%). Cytotoxicity patterns against intestinal epithelial cell lines suggest different functional subsets of CD8(+) IELs. CD clones capable of high cytotoxicity produced IL-2 whereas most cytotoxic NCD IELs produced IL-10. This clonal analysis indicates that an impaired immune regulation in celiac mucosa may be partially attributed to the low generation of regulatory CD8(+) IELs that produce IL-10.

A decapeptide from durum wheat prevents celiac peripheral blood lymphocytes from activation by gliadin peptides

Identifying antagonist peptides able to inhibit the abnormal immune response triggered by gliadin peptides in celiac disease (CD) is an alternative therapeutic strategy for CD. The aim of this study was to evaluate the antagonist effect of 10mer, a decapeptide (sequence QQPQDAVQPF) from alcohol-soluble protein fraction of durum wheat, assessing its ability to prevent celiac peripheral blood lymphocytes from activation by gliadin peptides. Peripheral blood mononuclear cells (PBMC) were obtained from DQ2-positive untreated coeliac children and from healthy controls and incubated with the peptic-tryptic digest of bread wheat gliadin (GLP) and peptide 62-75 from alpha-gliadin both alone and with 10mer simultaneously. PBMC proliferation, release of pro-inflammatory Th1 cytokines interferon-gamma and tumor necrosis factor-alpha, release of immunoregulatory cytokine IL-10, and analysis of CD25 expression as indexes of lymphocytes activation were carried out. Enhanced lymphocytes activation was seen after exposure to GLP and p62-75, whereas the simultaneous incubation with 10mer inhibits the lymphocytes response. These data indicate that a peptide naturally occurring in durum wheat exerts in vitro an antagonist effect against gliadin toxicity and could have a protective effect in CD disease.

Compartmentalised expression of meprin in small intestinal mucosa: enhanced expression in lamina propria in coeliac disease

Epithelial cells in the human small intestine express meprin, an astacin-like metalloprotease, which accumulates normally at the brush border membrane and in the gut lumen. Therefore, meprin is targeted towards luminal components. In coeliac disease patients, peptides from ingested cereals trigger mucosal inflammation in the small intestine, disrupting epithelial cell differentiation and function. Using in situ hybridisation on duodenal tissue sections, we observed a marked shift of meprin mRNA expression from epithelial cells, the predominant expression site in normal mucosa, to lamina propria leukocytes in coeliac disease. Meprin thereby gains access to the substrate repertoire present beneath the epithelium.

Gluten-free diet impact on leptin levels in asymptomatic coeliac adolescents: one year of follow-up

Coeliac disease, daily more frequently diagnosed in our population, involves many organs also in oligosymptomatic patients and with an adequate nutritional regime. Possible endocrine implications include failure to thrive, pubertal delay and reproduction diseases due to deregulation of GH, FSH and LH secretion. Leptin, an adipose tissue hormone, can be decreased as well and its deficiency could be related to growth and puberty anomalies. We studied 14 asymptomatic coeliac patients in peripubertal age (7.5-13.8 years) and tested their leptin levels in order to correlate them with endocrine and anthropometric data. Before the diet was started leptinaemia (M+/-DS) was: 4.94+/-5.53 ng/ml. In 10/14 patients (71%) leptinaemia was<or=2 DS for gender and age. In all the patients, after a period of 6-12 months of gluten-free diet, Leptin levels appreciably raised to 10.8+/-7.9 ng/ml, with a significant correlation to the time of the diet. Leptinaemia was actually lower in patients with a severe mucosal atrophy, and in these patients it increased more significantly after the diet was started. The removal of gluten itself may reduce immunological hit to adipose tissue and the 'malnutrition' of adipocytes: leptin can hence increase despite no significant increase of body mass index occurs. This study could partially explain the correlation between body mass index, Coeliac disease and the deregulation of puberty and fertility, mainly in patients who started the diet late. It could also explain the reversibility of this alteration if the cause is removed.

Gliadin-Specific Type 1 Regulatory T Cells from the Intestinal Mucosa of Treated Celiac Patients Inhibit Pathogenic T Cells

Celiac disease (CD) results from a permanent intolerance to dietary gluten and is due to a massive T cell-mediated immune response to gliadin, the main component of gluten. In this disease, the regulation of immune responses to dietary gliadin is altered. Herein, we investigated whether IL-10 could modulate anti-gliadin immune responses and whether gliadin-specific type 1 regulatory T (Tr1) cells could be isolated from the intestinal mucosa of CD patients in remission. Short-term T cell lines were generated from jejunal biopsies, either freshly processed or cultured ex vivo with gliadin in the presence or absence of IL-10. Ex vivo stimulation of CD biopsies with gliadin in the presence of IL-10 resulted in suppression of Ag-specific proliferation and cytokine production, indicating that pathogenic T cells are susceptible to IL-10-mediated immune regulation. T cell clones generated from intestinal T cell lines were tested for gliadin specificity by cytokine production and proliferative responses. The majority of gliadin-specific T cell clones had a Th0 cytokine production profile with secretion of IL-2, IL-4, IFN-gamma, and IL-10 and proliferated in response to gliadin. Tr1 cell clones were also isolated. These Tr1 cells were anergic, restricted by DQ2 (a CD-associated HLA), and produced IL-10 and IFN-gamma, but little or no IL-2 or IL-4 upon activation with gliadin or polyclonal stimuli. Importantly, gliadin-specific Tr1 cell clones suppressed proliferation of pathogenic Th0 cells. In conclusion, dietary Ag-specific Tr1 cells are present in the human intestinal mucosa, and strategies to boost their numbers and/or function may offer new therapeutic opportunities to restore gut homeostasis.

Reduction of tissue transglutaminase autoantibody levels by gluten-free diet is associated with changes in subsets of peripheral blood lymphocytes in children with newly diagnosed coeliac disease

Tissue transglutaminase (tTG) autoantibodies decline after gluten-free diet in patients with coeliac disease. We tested the hypothesis that gluten-free diet-induced change in tTG autoantibody levels affects subsets of peripheral blood lymphocytes. Peripheral blood was obtained from 20 children with biopsy-proven active coeliac disease. Gluten-free diet was initiated and the children examined again after three and six months. tTG autoantibodies were measured in radioligand binding assays and lymphocyte subsets by flow cytometry. IgA-tTG levels at diagnosis, 2204 U/ml (median, range 113-24990), were reduced over six months to 76 U/ml (median, range 1-1261) (P < 0.001). At six months, 12/20 (60%) children had reduced their IgA-tTG levels to < 100 U/ml and these children showed a decrease in B cells (mean change -3.8%, P = 0.014), CD4+ T cells (mean -4.32%, P = 0.011) and CD4+ T cells expressing CD25high (mean change -0.62%, P = 0.036). In contrast, the CD4+CD25(high)CCR4+ T cell population increased during the same period (mean change 11.5%, P = 0.0036). The decline in IgA-tTG levels correlated to the decrease in B cells (r = 0.56, P = 0.01), CD4+ T cells (r = 0.66, P = 0.004) as well as CD4+CD25high T cells (r = 0.59, P = 0.01). A negative correlation was found between the decline in IgA-tTG and CD4+CD25high T cells expressing CD45RO (r = -0.49, P = 0.03) and CCR4 (r = -0.54, P = 0.01). This is the first observational study on the effect of gluten-free diet on concurrent changes of tTG autoantibodies and specific peripheral blood lymphocyte subsets. Our data suggest that flow cytometry may be a useful complement to tTG autoantibodies when studying the effects of gluten-free diet in children with coeliac disease.

Analysis of candidate genes in celiac disease: a tool to identify life-threatening associated genes?

The authors have recently reported that celiac patients show a proinflammatory cytokine genetic profile characterized by the contemporaneous presence of both the tumour necrosis factor-alpha-308A and the interferon-gamma +874T allele-positive genotypes. The same alleles are considered risk factors for aging associated disease, whereas an anti-inflammatory cytokine genotype profile might be associated with an extended life expectancy. This paper reports data on the 1249-1250InsACAA/Non-Ins transforming growth factor (TGF)-beta2, a multifunctional anti-inflammatory cytokine, polymorphism distribution in 88 celiac disease (CD) patients, 99 age- and sex-matched controls, and 28 >95-year-old healthy subjects living in western Sicily. These data demonstrate that genotype frequencies of CD patients are not different from that of age-matched and >95-year-old healthy control subjects. These data might suggest that TGF-beta2 polymorphism is not involved in the complex genotypes associated with successful or unsuccessful aging. In addition, one can speculate that the genotype profile associated with CD susceptibility might be detrimental for longevity, and studies of this CD genetic asset might point to a candidate gene for antiaging strategies.

"Coelionomics": towards understanding the molecular pathology of coeliac disease

Coeliac disease (CD) is an inflammatory disorder of the small intestine characterised by a permanent intolerance to gluten-derived peptides. When gluten-derived peptides reach the lamina propria in CD patients, they provoke specific changes in the mucosa of their small intestine. Although the susceptibility to CD is strongly determined by environmental gluten, it is clearly a common genetic disorder. Important genetic factors for CD are the HLA-DQ genes located in the MHC region on chromosome 6 [HLA-DQ2 (95%) or HLA-DQ8 ( approximately 5%) heterodimers]. So far, the only treatment for CD consists of a life-long gluten-free diet. A key question in CD is why the gluten-derived peptides are resistant to further breakdown by endogenous proteases and how, in turn, they can activate a harmful immune response in the lamina propria of genetically predisposed individuals. Four mechanisms, namely apoptosis, oxidative stress, matrix metalloproteinases and dysregulation of proliferation and differentiation, are thought to play a role in the pathophysiology of CD. Whether the genes involved in these four mechanisms play a causative role in the development of the villous atrophy or are, in fact, a consequence of the disease process is unknown. In this review we summarise these mechanisms and discuss their validity in the context of current insights derived from genetic, genomic and molecular studies. We also discuss future directions for research and the therapeutic implications for patients.

TNFalpha, IFNgamma and IL-10 gene polymorphisms in a sample of Sicilian patients with coeliac disease

BACKGROUND

Coeliac disease is associated with DQ2 and DQ8 alleles, but other genes also confer an additional genetic risk.

AIMS

Defining whether the genetic profiles of interleukin-10, tumour necrosis factor alpha and interferon gamma are associated with an increased coeliac disease risk.

PATIENTS AND METHODS

The functionally gene polymorphisms of tumour necrosis factor alpha (-308G/A), interferon gamma (+874T/A) and interleukin-10 (-1082G/A) were typed using sequence specific primer-polymerase chain reaction in 110 Sicilian coeliac disease patients and in 220 Sicilian healthy controls.

RESULTS

No differences in genotype frequencies of interleukin-10 polymorphisms were found between coeliac disease patients and healthy controls. A significant increase of -308A (p<0.033; OR: 1.72; CI: 1.27-2.33) and of +874T (p: 0.0045; OR: 3.02; CI: 1.47-6.21) allele frequencies, both in hetero- and homozygosis, was observed in coeliac patients in comparison with healthy controls. In addition, simultaneous significant higher percentages of -308A and +874T alleles (p: 0.0066; OR: 2.33; CI: 1.42-3.82) as well as simultaneous significant lower percentages of -308A and +874T alleles (p: 0.003; OR: 0.23; CI: 0.10-0.60) were observed in coeliac patients compared with healthy controls.

CONCLUSIONS

Genetically determined higher frequencies of -308A tumour necrosis factor alpha and +874T interferon gamma alleles, both in hetero and in homozygosis and mostly whether simultaneous, may play a role in predisposing to gluten intolerance. Subjects positive for -308A tumour necrosis factor alpha and +874T interferon gamma alleles have an increased risk for coeliac disease.

Citocinas en la patogenia de la enfermedad celíaca

Celiac disease is manifested by an enteropathy caused by intolerance to gluten, a family of proteins found in wheat and other cereals. Following intestinal T-cell activation in predisposed individuals, different inflammatory mechanisms are triggered under the control of the cytokine balance including those with a pro-inflammatory Th1 pattern such as IFNgamma, TNFalpha, IL-15 and IL-18; and regulatory cytokines such as TGFbeta and IL-10. These cytokines, besides increasing the intensity of the activation and the number of immune cells within the intestinal mucosa, regulate the activity of epithelial growth factors and metalloproteinases, a group of molecules involved in the maintenance and turnover of the intestinal mucosa structure; in inflammatory conditions, they also induce the intestinal lesion responsible for malabsorption syndrome.

Elevated expression of iNOS mRNA and protein in coeliac disease

BACKGROUND

The role of nitric oxide synthase (NOS) in the pathophysiology of coeliac disease (CD) was investigated.

METHODS

We examined mRNA (reverse transcription multiplex polymerase chain reaction) and protein expression (Western blotting) of i,e and nNOS in enterocytes isolated from the duodenum of patients with untreated CD (n=22) and iron deficiency anaemia (IDA, n=22). Expression of IL1beta and TNFalpha, two pivotal "NOS-controlling" cytokines, was also studied.

RESULTS

Enterocytes from both patient groups were negative for eNOS and TNF(alpha) message but positive for n and iNOS. nNOS gene expression was not statistically different between groups (158.38+/-29.11% vs. 114.95+/-24.17%, IDA vs. CD, p=0.07, Mann-Whitney U). iNOS expression was higher in patients with CD when compared to patients with IDA (96.95+/-17.82% vs. 48.76+/-8.07%, p<0.006). Low levels of IL1beta mRNA (15.66+/-3.70%) were detected in nine samples-all of these samples were isolated from patients with CD representing a positive result in 40% of coeliac patients. In support of these observations, patients with CD expressed more iNOS protein than those with IDA (159.7+/-14.9% vs. 69.8+/-20%, p<0.05).

CONCLUSION

These results suggest that iNOS could be an important mediator in coeliac disease. Expression of this regulatory protein may be under the control of IL1beta.

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.

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.

A porous defense: the leaky epithelial barrier in intestinal disease

A critical function of the intestinal mucosa is to form a barrier that separates luminal contents from the interstitium. This intestinal barrier is compromised in a number of intestinal diseases, most notably inflammatory bowel disease. In vitro studies have demonstrated that cytokines elaborated by immune cells can cause the mucosal barrier to become leaky; these cytokines are known to be increased in intestinal mucosa involved in inflammatory bowel disease. Detailed information describing the mechanisms by which altered cytokine signaling occurs is not available, but recent data implicate the cytoskeleton within epithelial cells as a critical regulator of the mucosal barrier under physiological and pathophysiological conditions. Using available data, we describe a model of intestinal disease where an initial insult to the epithelial barrier may trigger a self-amplifying cycle of immune activation, cytokine release, and further barrier dysfunction. This model is supported by the observation that pharmacological abrogation of cytokine signaling corrects both barrier defects and clinical disease in animal models and human patients, although such therapy clearly has multiple mechanisms. Other therapeutic targets that represent strategies to prevent or reverse disease processes are also considered. The overarching hypothesis is that modulation of the mucosal epithelial barrier plays a critical role in the initiation and propogation of inflammatory intestinal diseases.

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.

Cytokine genotyping (TNF and IL-10) in patients with celiac disease and selective IgA deficiency

OBJECTIVE

Selective IgA deficiency (IgAD) and celiac disease (CD) are frequently associated and share the ancestral haplotype human leukocyte antigen (HLA)-8.1, which is characterized by a peculiar cytokine profile. The aim of this study was to evaluate the role of tumor necrosis factor (TNF) and interleukin (IL)-10 alleles in CD and CD-IgAD.

METHODS

The distribution of some biallelic polymorphisms of both cytokine promoters (-308G-->A and -863C-->A at TNF promoter sequence and -1082G-->A, -819C-->A, and -592C-->T at IL-10 promoter) were typed using biotilinated specific probes in 32 celiac patients, in 34 CD-IgAD patients, and in 96 healthy controls.

RESULTS

In CD and CD-IgAD, the -308A allele was significantly more frequent than in controls, whereas no significant differences were observed for the biallelic polymorphisms at the -863 and for the three IL-10 promoter polymorphisms. The evaluation of combined TNF and IL-10 genotypes showed in CD-IgAD a significant reduction of -308G/-1082G homozygous subjects and both in CD and CD-IgAD groups an increase of 308AA/1082GG. Accordingly, CD-IgAD patients positive both for -308A TNF and -1082A IL-10 showed an increase of TNF-alpha and a reduction of IL-10 serum levels.

CONCLUSIONS

Genetically determined increased production of TNF-alpha and reduction of IL-10 may be relevant for susceptibility to CD, mainly in IgAD, as the different allele expression at TNF and IL-10 loci seems to influence cytokine production profile.

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.

Persistent decreased plasma cholecystokinin levels in celiac patients under gluten-free diet: respective roles of histological changes and nutrient hydrolysis

Celiac disease is associated with impaired cholecystokinin (CCK) release. The mechanism by which CCK release is impaired is poorly understood and seems to be related to the mucosal atrophy or to decreased stimulation due to reduced intraduodenal nutrient hydrolysis. The aims of our study were to evaluate basal and postprandial CCK in celiac patients presenting with distinctive types of mucosal lesions (normal, infiltrative and atrophic), and to study the role of protein hydrolysis on CCK release. Plasma CCK was measured in 20 celiac patients (normal mucosa: n=6; infiltrative type: n=6; atrophic type=8) and 9 controls, before and after ingestion of a polymeric or a semi-elemental meal. Significant decreases in basal CCK plasma (B 0.6 [95% CI, 0.3-1.3] pmol/l; p<0.003) and postprandial CCK area under curve (AUC 34 [19-61] pmol/l x 120 min, p<0.0001) were observed in patients with an atrophic mucosa compared with treated patients (B 1.6 [1.0-2.4] pmol/l, AUC 267 [172-414] pmol/l x 120 min) or healthy volunteers (B 1.0 [0.7-1.4] pmol/l, AUC 186 [131-264] pmol/l x 120 min). A significant defective CCK release was also observed in patients with an infiltrative type: B 0.4 [0.2-0.7] pmol/l and AUC 56 [31-101] pmol/l x 120 min; p<0.0001. Administration of a semi-elemental diet did not correct the defective CCK release. In conclusion, the decreased CCK levels observed in celiac patients are not strictly related to the mucosal atrophy but rather to the lymphocytic infiltrate. Administration of a predigested meal did not correct the impaired CCK release. Some inhibitory mechanism could be involved in the CCK cell dysfunction observed in celiac patients presenting with lesser degrees of disease activity.

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.

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.

IFN-gamma induces transglutaminase 2 expression in rat small intestinal cells

Transglutaminase 2 (tissue transglutaminase, TGase 2) was recently identified as an endomysial autoantigen in celiac disease (CD). Identification of how TGase 2 expression is increased may allow a better understanding of this autoimmune disease. Certain inflammatory cytokines, tumor necrosis factor-alpha (TNF-alpha) and transforming growth factor-beta (TGF-beta), and the Th type I cytokine interferon-gamma (INF-gamma) are abundant in CD. We have investigated whether these play a role in the regulation of TGase 2 expression in a model rat small intestinal epithelial cell line (IEC-6). After treatment for 24 h, TNF-alpha did not significantly alter TGase 2 mRNA or activity, but TGF-beta decreased mRNA and activity by 4-5-fold. IFN-gamma increased mRNA and TGase 2 activity by about 2-fold in 24 h and 5-fold by 5 days. Our new data suggest that increased TGase 2 expression in the upper small intestine of CD patients may be due to increased IFN-gamma expression, loss of TGF-beta signaling, or both.

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.

Heat-shock protein 70-1 and HLA class II gene polymorphisms associated with celiac disease susceptibility in Navarra (Spain)

Heat shock proteins (HSP) are thought to play a role in the immune response making probable their contribution to celiac disease (CD). We studied the polymorphisms in the 5' regulatory region of the HSP70-1 gene and performed genomic HLA-DQ and -DR typing in 128 CD patients and 94 healthy controls from Navarra (Spain). The frequency of the C allele of the HSP70-1, characterized by the intermediate electrophoretic mobility of DNA, was significantly increased among CD patients (64.5% vs 37.2%. p <1 x 10(-7)). When subjects were stratified by the HLA II genotype, differences were statistically significant between DR3-negative or DR3-DQB1*02-negative CD patients and matched controls. Homozygosity for the DQB1*02 allele was present in 48.4% of CD patients and 12.8% of controls (OR = 6.4; CI:3.1 to 13.8; p <1 x 10(-7)). Similar increased risk was observed for DQB1*02/*02, DRB1*03/-, or DRB1*03/07 patients. Furthermore, those individuals expressing the classical HLA alleles in CD (DQB1*02/*02, DRB1*03/*07) who also carried the HSP70-1 CC genotype were twelve times more likely to develop the disease than the matched controls. We therefore conclude that although HSP70-1 gene does not seem to be primarily associated with CD, it might be a component of the high risk haplotype, playing a role as an additional predisposing gene for the disease.

Cytokine expression in unstimulated PBMC of children with type 1 diabetes and subjects positive for diabetes-associated autoantibodies

The aim of this study was to evaluate possible changes in the circulating levels of interferon (IFN)-gamma, interleukin (IL)-4 and transforming growth factor (TGF)-beta in association with the autoimmune process leading to type 1 diabetes. Expression levels of mRNAs specific for each cytokine were determined in peripheral blood mononuclear cells (PBMC) by a multiplex reverse transcription-polymerase chain reaction (RT-PCR) followed by hybridization reactions with lanthanide-labelled probes and detection by time-resolved fluorometry. Newly diagnosed diabetic children had lower levels of IFN-gamma, IL-4 and TGF-beta 1 signals compared to their age- and sex-matched controls (P < 0.02, P < 0.005 and P < 0.005, respectively) and also the autoantibody-positive subjects had significantly lower levels of IL-4 and TGF-beta 1 in comparison with their matched controls (P = 0.0013 and P = 0.012). No significant differences were observed when comparing matched pairs of diabetic children and autoantibody-positive subjects. Our results suggest a systemic bias towards reduced production of T-helper cell type 2 cytokines (IL-4 and TGF-beta 1) during the autoimmune process, but there was also a reduced level of IFN-gamma expression in the periphery at the onset of clinical diabetes.

Prevalence of silent coeliac disease in atopics

BACKGROUND

Coeliac disease sometimes runs a subclinical/silent course and is often associated with immunologic and non-immunologic diseases. Although atopy is described as one of the most frequently associated conditions, the prevalence of coeliac disease in atopics has not yet been established.

AIM

To evaluate the frequency of coeliac disease in an Italian series of atopics.

PATIENTS AND METHODS

Sera from 401 consecutive atopics with no clinical evidence of malabsorption were tested for IgA antiendomysial antibodies by indirect immunofluorescence on human umbilical cord and IgA anti tissue transglutaminase by enzyme-linked immunosorbent assay Results. Four patients (1%) were found to be positive for both autoantibodies. Intestinal biopsy confirmed the diagnosis of active coeliac disease. One of the 4 coeliacs was also affected by Down's syndrome, autoimmune thyroiditis and coeliac hepatitis. In another case, a previously unknown severe iron deficiency was detected.

CONCLUSIONS

The present study shows, for the first time, that the prevalence of coeliac disease in atopics is 1%, which is significantly higher than that in the general Italian population. Therefore, atopy should be considered a condition at risk and atopic patients routinely screened by means of specific autoantibody testing.

Interferon-gamma downregulates ion transport in murine small intestine cultured in vitro

Effects of IFN-gamma on mammalian small intestinal ion transport were studied in vitro using incubated sheets of murine small intestine in Ussing chambers. In oxygenated standard culture medium containing hydrocortisone and antibiotics, they maintained their short-circuit current (I(sc)) responses to glucose and theophylline for 48 h. Histological examination revealed a 50% diminution of villus height over 36 h but no change in crypts. Height was better maintained during a 36-h incubation of small intestine from SCID mice, suggesting a role for B or T lymphocytes in villus atrophy. Exposure of small intestine to 100 U/ml IFN-gamma for 36 h decreased basal I(sc) by 40% and I(sc) responses to glucose and theophylline by approximately 70%; at 1,000 U/ml for 36 h, IFN-gamma inhibited these I(sc) responses by 90%. An inhibitor of inducible NO synthase did not reverse these effects, suggesting that they are not mediated by NO. Tissue resistance, mucosal K(+) content, and epithelial morphology were not affected. Ouabain-sensitive ATPase activity in homogenates was inhibited 60% by IFN-gamma (100 U/ml for 36 h). IFN-gamma inhibition of I(sc) responses to glucose and theophylline also occurred in SCID mouse small intestine. Thus murine small intestinal sheets can be maintained viable in vitro for at least 48 h, although villus blunting develops (but less so in SCID mouse small intestine). Also, prolonged exposure to IFN-gamma downregulates Na(+)-coupled glucose absorption, active Cl(-) secretion, and Na(+)-K(+)-ATPase activity, effects unlikely to be mediated by enhanced NO.

In vivo antigen challenge in celiac disease identifies a single transglutaminase-modified peptide as the dominant A-gliadin T-cell epitope

Celiac disease (CD) is an increasingly diagnosed enteropathy (prevalence, 1:200-1:300) that is induced by dietary exposure to wheat gliadins (as well as related proteins in rye and barley) and is strongly associated with HLA-DQ2 (alpha1*0501, beta1*0201), which is present in over 90% of CD patients. Because a variety of gliadin peptides have been identified as epitopes for gliadin-specific T-cell clones and as bioactive sequences in feeding studies and in ex vivo CD intestinal biopsy challenge, it has been unclear whether a 'dominant' T-cell epitope is associated with CD. Here, we used fresh peripheral blood lymphocytes from individual subjects undergoing short-term antigen challenge and tissue transglutaminase-treated, overlapping synthetic peptides spanning A-gliadin to demonstrate a transient, disease-specific, DQ2-restricted, CD4 T-cell response to a single dominant epitope. Optimal gamma interferon release in an ELISPOT assay was elicited by a 17-amino-acid peptide corresponding to the partially deamidated peptide of A-gliadin amino acids 57-73 (Q65E). Consistent with earlier reports indicating that host tissue transglutaminase modification of gliadin enhances gliadin-specific CD T-cell responses, tissue transglutaminase specifically deamidated Q65 in the peptide of A-gliadin amino acids 56-75. Discovery of this dominant epitope may allow development of antigen-specific immunotherapy for CD.