Celiac disease is caused by an abnormal intestinal T cell response to cereal gluten proteins. The disease has a strong human leukocyte antigen (HLA) association, and CD4
+
T cells recognizing gluten ...epitopes presented by disease-associated HLA-DQ allotypes are considered to be drivers of the disease. This paper provides an update of the currently known HLA-DQ restricted gluten T cell epitopes with their names and sequences.
Celiac disease (CeD) is a chronic immuno-mediated enteropathy caused by dietary gluten with marked autoimmunity traits. The human leukocyte antigen (HLA) class II heterodimers represent the main ...predisposing factor, although environmental agents, as viral infection, gut microbiota, and dietary regimen, also contribute to CeD risk. These molecules are involved in autoimmunity as they present self-antigens to autoreactive T cells that have escaped the thymic negative selection. In CeD, the HLA class II risk alleles, DQA1*05-DQB1*02 and DQA1*03-DQB1*03, encode for DQ2.5 and DQ8 heterodimers, and, furthermore, disease susceptibility was found strictly dependent on the dose of these genes. This finding questioned how the expression of HLA-DQ risk genes, and of relative surface protein on antigen-presenting cells, might be relevant for the magnitude of anti-gluten inflammatory response in CeD patients, and impact the natural history of disease, its pathomechanisms, and compliance to dietary treatment. In this scenario, new personalized medical approaches will be desirable to support an early, accurate, and non-invasive diagnosis, and to define genotype-guided preventive and therapeutic strategies for CeD. To reach this goal, a stratification of genetic risk, disease outcome, and therapy compliance based on HLA genotypes, DQ2.5/DQ8 expression measurement and magnitude of T cell response to gluten is mandatory. IMPACT: This article revises the current knowledge on how different HLA haplotypes, carrying the DQ2.5/DQ8 risk alleles, impact the onset of CeD. This review discusses how the expression of susceptibility HLA-DQ genes can determine the risk assessment, outcome, and prevention of CeD. The recent insights on the environmental factors contributing to CeD in childhood are reviewed. This review discusses the use of HLA risk gene expression as a tool to support medical precision approaches for an early and non-invasive diagnosis of CeD, and to define genotype-guided preventive and therapeutic strategies.
Gluten proteins are the causative agent of Celiac Disease (CD), a life-long food intolerance characterized by an autoimmune enteropathy. Inadvertent gluten exposure is frequent even in celiac ...patients complying with a gluten-free diet, and the supplementation of exogenous gluten-digestive enzymes (glutenases) is indeed a promising approach to reduce the risk of dietary gluten boost. Here we describe Endopeptidase 40, a novel glutenase discovered as secreted protein from the soil actinomycete Actinoallomurus A8, and its recombinant active form produced by Streptomyces lividans TK24. E40 is resistant to pepsin and trypsin, and active in the acidic pH range 3 to 6. E40 efficiently degrades the most immunogenic 33-mer as well as the whole gliadin proteins, as demonstrated by SDS-PAGE, HPLC, LC-MS/MS, and ELISA. T lymphocytes from duodenal biopsies of celiac patients showed a strongly reduced or absent release of IFN-γ when exposed to gluten digested with E40. Data in gastrointestinal simulated conditions suggest that no toxic peptides are freed during gluten digestion by E40 into the stomach to enter the small intestine, thus counteracting the intestinal inflammatory cascade to occur in CD patients. E40 is proposed as a novel candidate in Oral Enzymatic Therapy for the dietary management of gluten toxicity.
► Casein and whey proteins were in vitro digested and applied to Caco-2 monolayers. ► Resistant peptides able to translocate across monolayers were characterised. ► Minor amount of supposed bioactive ...peptides were detected. ► After digestion milk proteins almost completely lost the IgE-binging properties. ► β-Lg 127–135 is a possible “immune sensitising factors” in vivo.
The entire panel of peptides produced from caseins (CN) and whey proteins (WP) that survive in vitro sequential gastro-pancreatic digestion and translocate across monolayers of Caco-2 cells, used as a model of the intestinal epithelium, has been characterised by HPLC and mass spectrometry. Among the milk-derived bioactive peptides, only minor amounts of mono-phosphorylated peptides arising from αs1- and β-CN were detected. The absorption behaviour of two resistant β-lactoglobulin (β-Lg) domains, β-Lg 125–135 and β-Lg 40–60, was studied in detail using synthetic peptides. The IgE-binding properties of the digests recovered from the apical and basolateral monolayer compartments were evaluated by dot-blot, using the sera of milk allergic children (N=5). Outcomes indicated β-Lg 127–135 as a possible “immune sensitising factor” in vivo. The almost complete loss of the IgE-affinity of CN and WP after digestion points out the need to design in vivo experiments to track the metabolic fate of dietary proteins.
The gluten-free diet is, to date, the only efficacious treatment for patients with Celiac Disease. In recent years, the impressive rise of Celiac Disease incidence, dramatically prompted changes in ...the dietary habit of an increasingly large population, with a rise in demand of gluten-free products. The formulation of gluten-free bakery products presents a formidable challenge to cereal technologists. As wheat gluten contributes to the formation of a strong protein network, that confers visco-elasticity to the dough and allows the wheat flour to be processed into a wide range of products, the preparation of cereal-based gluten-free products is a somehow difficult process. This review focuses on nutritional and technological quality of products made with gluten-free cereals available on the market. The possibility of using flour from naturally low toxic ancient wheat species or detoxified wheat for the diet of celiacs is also discussed.
In the recent years, the incidence of inflammatory bowel disease (IBD) has dramatically increased in young subjects, however, the pathogenesis of paediatric IBD is poorly investigated. In this study ...we aimed to evaluate the cytokine pattern and the phenotype of cytokine producing cells in the intestinal mucosa of paediatric patients affected by Crohn's disease (CD) or ulcerative colitis (UC) and of non-IBD healthy controls (HC). Cytokine (IL-15, TNF-α, INF-γ) production was analyzed at basal condition and after mitogen stimulation either intracellularly by flow cytometry or in intestinal cell culture supernatants by enzyme-linked immunosorbent assay (ELISA). A higher frequency of enterocytes (EpCam+ cells) was observed in UC patients compared to CD or HC. An expansion of enterocytes producing IL-15 and TNF-α were found in IBD patients compared to HC. A marked expression of IL-15 in the intestinal epithelium of IBD patients was further confirmed by immunohistochemistry. Myeloid dendritic (CD11c+) cells producing TNF-α and INF-γ were increased in IBD biopsies. Unexpectedly, only after a strong mitogen stimulus, as phytohaemagglutinin, the frequency of CD3+ cells producing IFN-γ was increased in IBD compared to control intestinal mucosa. Interestingly, functional studies performed on organ cultures of intestinal biopsies with neutralizing anti-IL-15 monoclonal antibody showed a marked reduction of mononuclear cell activation, proliferation of crypt enterocytes, as well as a reduction of TNF-α release in organ culture supernatants. In conclusion, we found that in the gut mucosa of IBD children both enterocytes and dendritic cells produce proinflammatory cytokines. The over-expression of IL-15 by enterocytes in IBD intestine and the reduced IBD inflammation by IL-15 blockage suggests that this cytokine could be a therapeutic target in IBD.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Immunological events that precede the development of villous atrophy in celiac disease (CeD) are still not completely understood. We aimed to explore CeD-associated antibody production (anti-native ...gliadin (AGA), anti-deamidated gliadin (DGP) and anti-tissue transglutaminase (anti-tTG)) in infants at genetic risk for CeD from the Italian cohorts of the PREVENT-CD and Neocel projects, as well as the relationship between antibody production and systemic inflammation. HLA DQ2 and/or DQ8 infants from families with a CeD case were followed from birth. Out of 220 at-risk children, 182 had not developed CeD by 6 years of age (CTRLs), and 38 developed celiac disease (CeD). The profiles of serum cytokines (INFγ, IL1β, IL2, IL4, IL6, IL10, IL12p70, IL17A and TNFα) and the expression of selected genes (FoxP3, IL10, TGFβ, INFγ, IL4 and IL2) were evaluated in 46 children (20 CeD and 26 CTRLs). Among the 182 healthy CTRLs, 28 (15.3%) produced high levels of AGA-IgA (AGA+CTRLs), and none developed anti-tTG-IgA or DGP-IgA, compared to 2/38 (5.3%) CeD infants (Chi Sq. 5.97,
= 0.0014). AGAs appeared earlier in CTRLs than in those who developed CeD (19 vs. 28 months). Additionally, the production of AGAs in CeD overlapped with the production of DGP and anti-tTG. In addition, gene expression as well as serum cytokine levels discriminated children who developed CeD from CTRLs. In conclusion, these findings suggest that the early and isolated production of AGA-IgA antibodies is a CeD-tolerogenic marker and that changes in gene expression and cytokine patterns precede the appearance of anti-tTG antibodies.
Environmental pollutants, including endocrine disruptor chemicals (EDCs), interfere on human health, leading to hormonal, immune and metabolic perturbations. Bisphenol-A (BPA), a main component of ...polycarbonate plastics, has been receiving increased attention due to its worldwide distribution with a large exposure. In humans, BPA, for its estrogenic activity, may have a role in autoimmunity, inflammatory and allergic diseases. To this aim, we assessed the effect of low BPA doses on functionality of human peripheral blood mononuclear cells (PBMCs), and on in vitro differentiation of dendritic cells from monocytes (mDCs). Fresh peripheral blood samples were obtained from 12 healthy adult volunteers. PBMCs were left unstimulated or were activated with the mitogen phytohemagglutinin (PHA) or the anti-CD3 and anti-CD28 antibodies and incubated in presence or absence of BPA at 0.1 and 1nM concentrations. The immune-modulatory effect of BPA was assessed by evaluating the cell proliferation and the levels of interferon-γ (IFN-γ), interleukin-4 (IL-4), interleukin-10 (IL-10) and interleukin-13 (IL-13) secreted by PBMCs. mDCs were differentiated with IL-4 and GC-CSF with or without BPA and the expression of differentiation/maturation markers (CD11c, CD1a, CD86, HLA-DR) was evaluated by flow cytometry; furthermore, a panel of 27 different cytokines, growth factors and chemokines were assayed in the mDC culture supernatants. PBMCs proliferation significantly increased upon BPA exposure compared to BPA untreated cells. In addition, a significant decrease in IL-10 secretion was observed in PBMCs incubated with BPA, either in unstimulated or mitogen-stimulated cells, and at both 0.1 and 1nM BPA concentrations. Similarly, IL-13 was reduced, mainly in cells activated by antiCD3/CD28. By contrast, no significant changes in IFN-γ and IL-4 production were found in any condition assayed. Finally, BPA at 1nM increased the density of dendritic cells expressing CD1a and concomitantly decreased the expression of HLA-DR and CD86 activation markers. In conclusion, in humans the exposure to BPA causes on PBMCs a significant modulation of proliferative capacity and cytokine production, and on mDCs alteration in differentiation and phenotype. These immune cell alterations suggest that low dose chronic exposure to BPA could be involved in immune deregulation and possibly in the increased susceptibility to develop inflammatory and autoimmune diseases.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Regulatory T cells (Tregs) play a critical role in maintaining immune homeostasis. We investigated two main types of Tregs, the CD4+FOXP3+ and IL-10+ Tr1, in pediatric subjects with inflammatory ...bowel disease (IBD) both at diagnosis and after the clinical remission.
Peripheral blood Tregs were analyzed in 16 children with Crohn's disease (CD), 19 with ulcerative colitis (UC), and 14 healthy controls (HC). Two cocktails of fluoresceinated antibodies were used to discriminate between CD4+FOXP3+ and Tr1.
We observed in both CD and UC groups a higher frequency of Tr1 at diagnosis compared to controls, which decreased at follow-up compared to diagnosis, in particular in UC. Similarly, in UC patients the percentage of CD4+FOXP3+ Tregs markedly decreased at follow-up compared to the same patients at diagnosis and compared to HC. The expression of CTLA-4 in CD4+FOXP3+ Tregs increased in both groups at clinical remission.
This study shows that IBD children present at diagnosis an increased frequency of circulating Tregs, probably as a compensative reaction to tissue inflammation. During the clinical remission, the Treg frequency diminishes, and concomitantly, their activation status increases. Notwithstanding, the high Treg density at diagnosis is not sufficient to counteract the inflammation in the childhood IBD.
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