T-cell and B-cell immunity in celiac disease

Potential of nutraceuticals in celiac disease

Celiac Disease (CD) is the most common hereditarily-based food intolerance worldwide and a chronic inflammatory condition. The current standard treatment for CD involves strict observance and compliance with a gluten-free diet (GFD). However, maintaining a complete GFD poses challenges, necessitating the exploration of alternative therapeutic approaches. Nutraceuticals, bioactive products bridging nutrition and pharmaceuticals, have emerged as potential candidates to regulate pathways associated with CD and offer therapeutic benefits. Despite extensive research on nutraceuticals in various diseases, their role in CD has been relatively overlooked. This review proposes comprehensively assessing the potential of different nutraceuticals, including phytochemicals, fatty acids, vitamins, minerals, plant-based enzymes, and dietary amino acids, in managing CD. Nutraceuticals exhibit the ability to modulate crucial CD pathways, such as regulating gluten fragment accessibility and digestion, intestinal barrier function, downregulation of tissue transglutaminase (TG2), intestinal epithelial morphology, regulating innate and adaptive immune responses, inflammation, oxidative stress, and gut microbiota composition. However, further investigation is necessary to fully elucidate the underlying cellular and molecular mechanisms behind the therapeutic and prophylactic effects of nutraceuticals for CD. Emphasizing such research would contribute to future developments in CD therapies and interventions.

Fecal microbiota transplantation in autoimmune diseases - An extensive paper on a pathogenetic therapy

The role of infections in the pathogenesis of autoimmune diseases has long been recognized and reported. In addition to infectious agents, the internal composition of the "friendly" living bacteria, (microbiome) and its correlation to immune balance and dysregulation have drawn the attention of researchers for decades. Nevertheless, only recently, scientific papers regarding the potential role of transferring microbiome from healthy donor subjects to patients with autoimmune diseases has been proposed. Fecal microbiota transplantation or FMT, carries the logic of transferring microorganisms responsible for immune balance from healthy donors to individuals with immune dysregulation or more accurately for our paper, autoimmune diseases. Viewing the microbiome as a pathogenetic player allows us to consider FMT as a pathogenetic-based treatment. Promising results alongside improved outcomes have been demonstrated in patients with different autoimmune diseases following FMT. Therefore, in our current extensive review, we aimed to highlight the implication of FMT in various autoimmune diseases, such as inflammatory bowel disease, autoimmune thyroid and liver diseases, systemic lupus erythematosus, and type 1 diabetes mellitus, among others. Presenting all the aspects of FMT in more than 12 autoimmune diseases in one paper, to the best of our knowledge, is the first time presented in medical literature. Viewing FMT as such could contribute to better understanding and newer application of the model in the therapy of autoimmune diseases, indeed.

SURGE: uncovering context-specific genetic-regulation of gene expression from single-cell RNA sequencing using latent-factor models

Genetic regulation of gene expression is a complex process, with genetic effects known to vary across cellular contexts such as cell types and environmental conditions. We developed SURGE, a method for unsupervised discovery of context-specific expression quantitative trait loci (eQTLs) from single-cell transcriptomic data. This allows discovery of the contexts or cell types modulating genetic regulation without prior knowledge. Applied to peripheral blood single-cell eQTL data, SURGE contexts capture continuous representations of distinct cell types and groupings of biologically related cell types. We demonstrate the disease-relevance of SURGE context-specific eQTLs using colocalization analysis and stratified LD-score regression.

Unraveling the Immunopathological Landscape of Celiac Disease: A Comprehensive Review

Celiac disease (CD) presents a complex interplay of both innate and adaptive immune responses that drive a variety of pathological manifestations. Recent studies highlight the role of immune-mediated pathogenesis, pinpointing the involvement of antibodies against tissue transglutaminases (TG2, TG3, TG6), specific HLA molecules (DQ2/8), and the regulatory role of interleukin-15, among other cellular and molecular pathways. These aspects illuminate the systemic nature of CD, reflecting its wide-reaching impact that extends beyond gastrointestinal symptoms to affect other physiological systems and giving rise to a range of pathological landscapes, including refractory CD (RCD) and, in severe cases, enteropathy-associated T cell lymphoma. The existing primary therapeutic strategy, a gluten-free diet (GFD), poses significant challenges, such as low adherence rates, necessitating alternative treatments. Emerging therapies target various stages of the disease pathology, from preventing immunogenic gluten peptide absorption to enhancing intestinal epithelial integrity and modulating the immune response, heralding potential breakthroughs in CD management. As the understanding of CD deepens, novel therapeutic avenues are emerging, paving the way for more effective and sophisticated treatment strategies with the aim of enhancing the quality of life of CD patients. This review aims to delineate the immunopathology of CD and exploring its implications on other systems, its complications and the development of novel treatments.

Identification of gluten T cell epitopes driving celiac disease

CD4⁺ T cells specific for cereal gluten proteins are key players in celiac disease (CeD) pathogenesis. While several CeD-relevant gluten T cell epitopes have been identified, epitopes recognized by a substantial proportion of gluten-reactive T cells remain unknown. The identification of such CeD-driving gluten epitopes is important for the food industry and in clinical settings. Here, we have combined the knowledge of a distinct phenotype of gluten-reactive T cells and key features of known gluten epitopes for the discovery of unknown epitopes. We tested 42 wheat gluten-reactive T cell clones, isolated on the basis of their distinct phenotype and with no reactivity to known epitopes, against a panel of synthetic peptides bioinformatically identified from a wheat gluten protein database. We were able to assign reactivity to 10 T cell clones and identified a 9-nucleotide oligomer core region of five previously uncharacterized gliadin/glutenin epitopes. This work represents an advance in the effort to identify CeD-driving gluten epitopes.

Profiling of peripheral blood B-cell transcriptome in children who developed coeliac disease in a prospective study

Background

In coeliac disease (CoD), the role of B-cells has mainly been considered to be production of antibodies. The functional role of B-cells has not been analysed extensively in CoD.

Methods

We conducted a study to characterize gene expression in B-cells from children developing CoD early in life using samples collected before and at the diagnosis of the disease. Blood samples were collected from children at risk at 12, 18, 24 and 36 months of age. RNA from peripheral blood CD19⁺ cells was sequenced and differential gene expression was analysed using R package Limma.

Findings

Overall, we found one gene, HNRNPL, modestly downregulated in all patients (logFC -0·7; q = 0·09), and several others downregulated in those diagnosed with CoD already by the age of 2 years.

Interpretation

The data highlight the role of B-cells in CoD development. The role of HNRPL in suppressing enteroviral replication suggests that the predisposing factor for both CoD and enteroviral infections is the low level of HNRNPL expression.

Funding

EU FP7 grant no. 202063, EU Regional Developmental Fund and research grant PRG712, The Academy of Finland Centre of Excellence in Molecular Systems Immunology and Physiology Research (SyMMyS) 2012-2017, grant no. 250114) and, AoF Personalized Medicine Program (grant no. 292482), AoF grants 292335, 294337, 319280, 31444, 319280, 329277, 331790) and grants from the Sigrid Jusélius Foundation (SJF).

Enteric Glial Cells in Immunological Disorders of the Gut

Enteric glial cells (EGCs) are one of the major cell types of neural crest lineage distributed in the gastrointestinal tract. EGCs represent an integral part of the enteric nervous system (ENS) and significantly outnumber ENS neurons. Studies have suggested that EGCs would exert essential roles in supporting the survival and functions of the ENS neurons. Notably, recent evidence has begun to reveal that EGCs could possess multiple immune functions and thereby may participate in the immune homeostasis of the gut. In this review article, we will summarize the current evidence supporting the potential involvement of EGCs in several important immunological disorders, including inflammatory bowel disease, celiac disease, and autoimmune enteropathy. Further, we highlight critical questions on the immunological aspects of EGCs that warrant future research attention.

How does a celiac iceberg really float? The relationship between celiac disease and gluten

Celiac disease (CD) is an autoimmune intestinal disease caused by intolerance of genetically susceptible individuals after intake of gluten-containing grains (including wheat, barley, etc.) and their products. Currently, CD, with "iceberg" characteristics, affects a large population and is distributed over a wide range of individuals. This present review summarizes the latest research progress on the relationship between CD and gluten. Furthermore, the structure and function of gluten peptides related to CD, gluten detection methods, the effects of processing on gluten and gluten-free diets are emphatically reviewed. In addition, the current limitations in CD research are also discussed. The present work facilitates a comprehensive understanding of CD as well as gluten, which can provide a theoretical reference for future research.

[Update on celiac disease]

Celiac disease is a T-cell-mediated autoimmune disorder. It is relevant to us for two very different reasons. Firstly, it has a prevalence of 1 % in the European population. Thus, a huge number of celiac patients remains undiagnosed. Secondly, the celiac trigger, gluten, functions as a "switch", that has the potential to selectively activate celiac immune pathology, thereby allowing us to uncover previously unknown immune conditions. This again contributes to new celiac treatment modalities that will presumably alleviate the future fate of celiac disease patients. In 2022, the German guidelines for celiac disease are published by the Deutsche Gesellschaft für Verdauungs- und Stoffwechselkrankheiten (DGVS). We have summarized some of the recommendations published therein.

Celiac Disease Revisited

Celiac disease (CD) is a systemic disease triggered by gluten ingestion in genetically predisposed individuals. It manifests primarily as an autoimmune enteropathy associated with specific circulating autoantibodies and a human leukocyte antigen haplotype (HLA-DQ2 or HLA-DQ8). It afflicts roughly 1% of the population, though the majority of patients remain undiagnosed. Diarrhea and malabsorption are classic manifestations of CD; however, both children and adults can be paucisymptomatic and present extraintestinal manifestations such as anemia, osteoporosis, and abnormal liver tests. CD screening is not recommended for the general population, and it should be focused on high-risk groups. CD diagnosis is challenging and relies on serological tests, duodenal histology, and genetic testing. Particularly difficult presentations to manage are seronegative patients, seropositive patients without villus atrophy, and patients who have started a gluten-free diet before the diagnostic workup. The only proven treatment is a lifelong gluten-free diet. We present an in-depth review on the physiopathology and management of CD, with a particular emphasis on diagnostic challenges.

Single-cell approaches to dissect adaptive immune responses involved in autoimmunity: the case of celiac disease

Single-cell analysis is a powerful technology that has found widespread use in recent years. For diseases with involvement of adaptive immunity, single-cell analysis of antigen-specific T cells and B cells is particularly informative. In autoimmune diseases, the adaptive immune system is obviously at play, yet the ability to identify the culprit T and B cells recognizing disease-relevant antigen can be difficult. Celiac disease, a widespread disorder with autoimmune components, is unique in that disease-relevant antigens for both T cells and B cells are well defined. Furthermore, the celiac disease gut lesion is readily accessible allowing for sampling of tissue-resident cells. Thus, disease-relevant T cells and B cells from the gut and blood can be studied at the level of single cells. Here we review single-cell studies providing information on such adaptive immune cells and outline some future perspectives in the area of single-cell analysis in autoimmune diseases.

TG2-gluten complexes as antigens for gluten-specific and transglutaminase-2 specific B cells in celiac disease

A hallmark of celiac disease is the gluten-dependent production of antibodies specific for deamidated gluten peptides (DGP) and the enzyme transglutaminase 2 (TG2). Both types of antibodies are believed to result from B cells receiving help from gluten-specific CD4⁺ T cells and differentiating into antibody-producing plasma cells. We have here studied the collaboration between DGP- and TG2-specific B cells with gluten-specific CD4⁺ T cells using transgenic mice expressing celiac patient-derived T-cell and B-cell receptors, as well as between B-cell transfectants and patient-derived gluten-specific T-cell clones. We show that multivalent TG2-gluten complexes are efficient antigens for both TG2-specific and DGP-specific B cells and allow both types of B cells to receive help from gluten-specific T cells of many different specificities.

Missing Insight Into T and B Cell Responses in Dermatitis Herpetiformis

Dermatitis herpetiformis is a cutaneous form of celiac disease manifesting as an itching rash typically on the elbows, knees and buttocks. It is driven by the ingestion of gluten-containing cereals and characterized by granular deposits of immunoglobulin A in the papillary dermis. These antibodies target transglutaminase (TG) 3 and in the majority of patients they are also found in circulation. The circulating antibodies disappear and skin symptoms resolve as a result of gluten-free diet but the cutaneous anti-TG3 IgA deposits may persist for several years. In dermatitis herpetiformis, plasma cells secreting antibodies against TG3 are located in the intestinal mucosa similarly to those producing TG2 antibodies characteristic for celiac disease. In fact, both TG2- and TG3-specific plasma cells and gluten responsive T cells are found in dermatitis herpetiformis patients but the interplay between these cell populations is unknown. The small bowel mucosal damage in celiac disease is believed to be mediated by co-operation of cytotoxic intraepithelial T cells and the inflammatory milieu contributed by gluten-reactive CD4+ T cells, whereas the skin lesions in dermatitis herpetiformis appear to be devoid of gluten reactive T cells. Thus, how celiac disease-type intestinal T and B cell responses develop into an autoimmune condition affecting the skin is still incompletely understood. Finally, the skin and small bowel lesions may reappear upon reintroduction of gluten in patients treated with gluten-free diet but virtually nothing is known about the long-lived B cell and memory T cell populations activating in response to dietary gluten in dermatitis herpetiformis.

Gliadin Sequestration as a Novel Therapy for Celiac Disease: A Prospective Application for Polyphenols

Celiac disease is an autoimmune disorder characterized by a heightened immune response to gluten proteins in the diet, leading to gastrointestinal symptoms and mucosal damage localized to the small intestine. Despite its prevalence, the only treatment currently available for celiac disease is complete avoidance of gluten proteins in the diet. Ongoing clinical trials have focused on targeting the immune response or gluten proteins through methods such as immunosuppression, enhanced protein degradation and protein sequestration. Recent studies suggest that polyphenols may elicit protective effects within the celiac disease milieu by disrupting the enzymatic hydrolysis of gluten proteins, sequestering gluten proteins from recognition by critical receptors in pathogenesis and exerting anti-inflammatory effects on the system as a whole. This review highlights mechanisms by which polyphenols can protect against celiac disease, takes a critical look at recent works and outlines future applications for this potential treatment method.

Human intestinal dendritic cell and macrophage subsets in coeliac disease

Dendritic cells (DC) and macrophages (Mϕ) constitute the most abundant antigen presenting cells in the human intestinal mucosa. In resting conditions, they are essential to maintain the mechanisms of immune tolerance toward food antigens and commensals, at the time that they keep the capacity to initiate and maintain antigen-specific pro-inflammatory immune responses toward invading pathogens. Nevertheless, this delicate equilibrium between immunity and tolerance is not perfect, like in coeliac disease (CD), where DC and Mϕ drive the development of antigen-specific immune responses toward dietary gluten peptides. In this review, we provide therefore a comprehensive discussion about CD pathogenesis, the human intestinal immune system and the biology of intestinal DC and Mϕ both in resting conditions and in CD. Last, but not least, we discuss about all the remaining issues pending to be studied regarding DC and Mϕ contribution toward CD pathogenesis. This may allow the identification of unique and specific factors which may be useful in the clinical practice, as well as identify new therapeutic targets in order to reestablish the loss intestinal homeostasis in CD.

Epithelial cell dysfunction in coeliac disease

The intestinal epithelium limits host-luminal interactions and maintains gut homeostasis. Breakdown of the epithelial barrier and villous atrophy are hallmarks of coeliac disease. Besides the well characterized immune-mediated epithelial damage induced in coeliac mucosa, constitutional changes and early gluten direct effects disturb intestinal epithelial cells. The subsequent modifications in key epithelial signaling pathways leads to outnumbered immature epithelial cells that, in turn, facilitate epithelial dysfunction, promote crypt hyperplasia, and increase intestinal permeability. Consequently, underlying immune cells have a greater access to gluten, which boosts the proinflammatory immune response against gluten and positively feedback the epithelial damage loop. Gluten-free diet is an indispensable treatment for coeliac disease patients, but additional therapies are under development, including those that reinforce intestinal epithelial healing. In this chapter, we provide an overview of intestinal epithelial cell disturbances that develop during gluten intake in coeliac disease mucosa.

Optimising the use of proteins from rich meat co-products and non-meat alternatives: Nutritional, technological and allergenicity challenges

An exponential growth in the global demand for high quality proteins over the next 20 years is expected, mainly due to global population growth and the increasing awareness toward protein rich foods for more nutritive diets. Coupled with this, is the pressing need for more sustainable approaches within a bio-economy mindset. Although meat production is expected to increase to address this rising demand, a better use of the currently available resources provided by the food, and specially, the meat industry is required. In this regard, despite the high-quality proteins and other nutrients found in meat co-products; they are currently underused and their valorisation needs to be revisited. Also, emerging protein sources need to be investigated to alleviate the environmental pressure coming from the meat industry. In this review, the main focus was attributed to (i) the current and forthcoming challenges for the use of meat co-products as meat replacers to produce a new range of meat derived products (with high nutritional value, improved technological properties and better consumer acceptance); (ii) their performance regarding to the non-animal origin proteins currently used as meat protein replacers; and (iii) the allergenicity of the proteins that might fall into the category of novel protein sources.

In Celiac Disease Patients the In Vivo Challenge with the Diploid Triticum monococcum Elicits a Reduced Immune Response Compared to Hexaploid Wheat

SCOPE

Gluten from the diploid wheat Triticum monococcum (TM) has low content of immunostimulatory sequences and a high gastro-intestinal digestibility. Gluten-reactive T cells elicited by diploid and hexaploid (Triticum aestivum-TA) wheat in celiac disease (CD) patients upon a brief oral challenge are analyzed.

METHODS AND RESULTS

Seventeen patients with CD (median age 13 years) consumed for 3 days sandwiches made with TM (cultivar Norberto-ID331, N=11), or TA (cultivar Sagittario, N=11) flours, corresponding to 12 gr of gluten/die. Immunostimulatory properties are assessed in blood by measuring the IFN-γ-secreting T cells by EliSpot and the expression of inflammatory cytokines/receptors (IL-12A, IL-15, IL-18RAP, IFN-γ) by qPCR. TA mobilizes a remarkable number of gliadin-specific, IFN-γ-secreting T cells (p<0.05), while no significant cell mobilization is induced by TM (p=ns). Similar results are obtained in response to five immunogenic peptides from α-, ω-, and γ-gliadins, although with a large individual variability. An increased mRNA expression for IL-12A and IFN-γ is detected in the group eating TA compared to those consuming TM (p<0.05).

CONCLUSIONS

Although T. monococcum is a cereal not suitable for the diet of celiacs, this diploid wheat elicits a reduced in vivo T-cell response compared to T. aestivum in celiac patients.

Identification of Isopeptides Between Human Tissue Transglutaminase and Wheat, Rye, and Barley Gluten Peptides

Celiac disease (CD) is a chronic immune-mediated enteropathy of the small intestine, which is triggered by the ingestion of storage proteins (gluten) from wheat, rye, and barley in genetically predisposed individuals. Human tissue transglutaminase (TG2) plays a central role in the pathogenesis of CD, because it is responsible for specific gluten peptide deamidation and covalent crosslinking, resulting in the formation of N^ε-(γ-glutamyl)-lysine isopeptide bonds. The resulting TG2-gluten peptide complexes are assumed to cause the secretion of anti-TG2 autoantibodies, but the underlying mechanisms are only partly known. To gain more insight into the structures of these complexes, the aim of our study was to identify TG2-gluten isopeptides. With the use of discovery-driven as well as targeted nanoscale liquid chromatography tandem mass spectrometry, we detected 29 TG2-gluten isopeptides in total, involving seven selected TG2 lysine residues (K205, K265, K429, K468, K590, K600, K677). Several gluten peptides carried known B-cell epitopes and/or T-cell epitopes, either intact 9-mer core regions or partial sequences, as well as sequences bearing striking similarities to already known epitopes. These novel insights into the molecular structures of TG2-gluten peptide complexes may help clarify their physiological relevance in the initiation of CD autoimmunity and the role of anti-TG2 autoantibodies.

Comprehensive Detection of Isopeptides between Human Tissue Transglutaminase and Gluten Peptides

Celiac disease (CD) is a chronic inflammation of the small intestine triggered by the ingestion of gluten in genetically predisposed individuals. Tissue transglutaminase (TG2) is a key factor in CD pathogenesis, because it catalyzes both the deamidation of specific glutamine residues and the formation of covalent Nε-(γ-glutamyl)-lysine isopeptide crosslinks resulting in TG2–gluten peptide complexes. These complexes are thought to activate B cells causing the secretion of anti-TG2 autoantibodies that serve as diagnostic markers for CD, although their pathogenic role remains unclear. To gain more insight into the molecular structures of TG2-gluten peptide complexes, we used different proteomics software tools that enable the comprehensive identification of isopeptides. Thus, 34 different isopeptides involving 20 TG2 lysine residues were identified in a model system, only six of which were previously known. Additionally, 36 isopeptides of TG2-TG2 multimers were detected. Experiments with different TG2-gluten peptide molar ratios revealed the most preferred lysine residues involved in isopeptide crosslinking. Expanding the model system to three gluten peptides with more glutamine residues allowed the localization of the preferred glutamine crosslinking sites. These new insights into the structure of TG2-gluten peptide complexes may help clarify the role of extracellular TG2 in CD autoimmunity and in other inflammatory diseases.

CD38 expression on gluten-specific T cells is a robust marker of gluten re-exposure in coeliac disease

Background

Increasing efforts are being put into new treatment options for coeliac disease (CeD), a chronic disorder of the small intestine induced by gluten. Interleukin-2 (IL-2) and gluten-specific CD4 + T cells increase in the blood after four hours and six days, respectively, following a gluten challenge in CeD patients. These responses are unique to CeD and are not seen in controls. We aimed to evaluate different markers reflecting a recall response to gluten exposure that may be used to monitor therapy.

Methods

CeD patients on a gluten-free diet underwent a one- (n = 6) or three-day (n = 7) oral gluten challenges. We collected blood samples at several time points between baseline and day 8, and monitored gluten-specific CD4 + T cells for their frequency and CD38 expression using HLA-DQ:gluten tetramers. We assessed the IL-2 concentration in plasma four hours after the first gluten intake.

Results

The frequency of gut-homing, tetramer-binding, CD4 + effector memory T (tetramer + β7 + T_EM) cells and the IL-2 concentration measured shortly after the first dose of gluten increased significantly after the one- and three-day gluten challenges, but large interindividual differences were exhibited. The frequency of tetramer + β7 + T_EM plateaued between days 6 and 8 and was lower after the one-day challenge. We observed a consistent increase in CD38 expression on tetramer + β7 + T_EM cells and did not find a significant difference between the one- and three-day challenges.

Conclusions

The optimal time points for monitoring therapy response in CeD after a three-day oral gluten challenge is four hours for plasma IL-2 or six to eight days for the frequency of tetramer + β7 + T_EM cells, but both these parameters involved large interindividual differences. In contrast, CD38 expression on tetramer + β7 + T_EM cells increased uniformly and irrespectively of the length of gluten challenge, suggesting that this parameter is more suited for monitoring drug efficacy in clinical trials for CeD.

Role of Dietary Gluten in Development of Celiac Disease and Type I Diabetes: Management Beyond Gluten-Free Diet

Gluten triggers Celiac Disease (CD) and type I diabetes in genetically predisposed population of human leukocyte antigen DQ2/DQ8+ and associates with disorders such as schizophrenia and autism. Application of a strict gluten-free diet is the only well-established treatment for patients with CD, whereas the treatment for patients with celiac type I diabetes may be depend on the timing and frequency of the diet. The application of a gluten-free diet in patients with CD may contribute to the development of metabolic syndrome and nonalcoholic fatty liver disease and may also lead to a high glycemic index, low fiber diet and micronutrient deficiencies. The alteration of copper bioavailability (deficient, excess or aberrant coordination) may contribute to the onset and progress of related pathologies. Therefore, nutrient intake of patients on a gluten-free diet should be the focus of future researches. Other gluten-based therapies have been rising with interest such as enzymatic pretreatment of gluten, oral enzyme supplements to digest dietary gluten, gluten removal by breeding wheat varieties with reduced or deleted gluten toxicity, the development of polymeric binders to suppress gluten induced pathology.

Novel screening test for celiac disease using peptide functionalised gold nanoparticles

AIM

To develop a screening test for celiac disease based on the coating of gold nanoparticles with a peptide sequence derived from gliadin, the protein that triggers celiac disease.

METHODS

20 nm gold nanoparticles were first coated with NeutrAvidin. A long chain Polyethylene glycol (PEG) linker containing Maleimide at the Ω-end and Biotin group at the α-end was used to ensure peptide coating to the gold nanoparticles. The maleimide group with the thiol (-SH) side chain reacted with the cysteine amino acid in the peptide sequence and the biotinylated and PEGylated peptide was added to the NeutrAvidin coated gold nanoparticles. The peptide coated gold nanoparticles were then converted into a serological assay. We used the peptide functionalised gold nanoparticle-based assay on thirty patient serum samples in a blinded assessment and compared our results with the previously run serological and pathological tests on these patients.

RESULTS

A stable colloidal suspension of peptide coated gold nanoparticles was obtained without any aggregation. An absorbance peak shift as well as color change was caused by the aggregation of gold nanoparticles following the addition of anti-gliadin antibody to peptide coated nanoparticles at levels associated with celiac disease. The developed assay has been shown to detect anti-gliadin antibody not only in quantitatively spiked samples but also in a small-scale study on real non-hemolytic celiac disease patient’s samples.

CONCLUSION

The study demonstrates the potential of gold nanoparticle-peptide based approach to be adapted for developing a screening assay for celiac disease diagnosis. The assay could be a part of an exclusion based diagnostic strategy and prove particularly useful for testing high celiac disease risk populations.

Leaky Gut, Leaky Brain?

'Leaky gut' syndrome, long-associated with celiac disease, has attracted much attention in recent years and for decades, was widely known in complementary/alternative medicine circles. It is often described as an increase in the permeability of the intestinal mucosa, which could allow bacteria, toxic digestive metabolites, bacterial toxins, and small molecules to 'leak' into the bloodstream. Nervous system involvement with celiac disease is know to occur even at subclinical levels. Gluten and gluten sensitivity are considered to trigger this syndrome in individuals genetically predisposed to celiac disease. However, the incidence of celiac disease in the general population is quite low. Nevertheless, increased public interest in gluten sensitivity has contributed to expanded food labels stating 'gluten-free' and the proliferation of gluten-free products, which further drives gluten-free lifestyle changes by individuals without frank celiac disease. Moreover, systemic inflammation is associated with celiac disease, depression, and psychiatric comorbidities. This mini-review focuses on the possible neurophysiological basis of leaky gut; leaky brain disease; and the microbiota's contribution to inflammation, gastrointestinal, and blood-brain barrier integrity, in order to build a case for possible mechanisms that could foster further 'leaky' syndromes. We ask whether a gluten-free diet is important for anyone or only those with celiac disease.

Analysis of IL17A and IL21 Expression in the Small Intestine of Celiac Disease Patients and Correlation with Circulating Thioredoxin Level

AIMS

Th17 cells and their related cytokines play an important role in the pathogenesis of celiac disease (CD), and thioredoxin (Trx) is an extracellular TG2 activity regulator. This study evaluated Trx serum levels and the expression levels of IL17A, IL21, and Trx genes in biopsies of treated (gluten-free diet) and naïve (untreated) CD patients compared with healthy individuals.

METHODS

Duodenal biopsies were collected from treated CD patients (n = 60), healthy controls (n = 60), and eight newly diagnosed celiac patients. IL17A, IL21, and Trx gene expression was assessed by quantitative polymerase chain reaction (qPCR) and compared with serum Trx levels assessed by enzyme-linked immunosorbent assay (ELISA).

RESULTS

Expression levels of the IL21 and Trx genes were not significantly modulated in the CD group compared to the control group, whereas the IL17A gene in CD patients was transcribed at significantly higher levels among the CD group. Serum concentrations of Trx were significantly increased in treated CD patients compared to the control group.

CONCLUSIONS

We observed that IL17A gene is more highly expressed in duodenal biopsies of CD patients than controls, and that the serum levels of Trx are significantly higher in treated CD patients than controls. Therefore, the expression levels of these genes and gene products, respectively, could potentially be used as diagnostic biomarkers for CD patients, although more studies are needed to unravel the underlying molecular mechanisms.

Autoimmunity in narcolepsy

PURPOSE OF REVIEW

Summarize the recent findings in narcolepsy focusing on the environmental and genetic risk factors in disease development.

RECENT FINDINGS

Both genetic and epidemiological evidence point towards an autoimmune mechanism in the destruction of orexin/hypocretin neurons. Recent studies suggest both humoral and cellular immune responses in the disease development.

SUMMARY

Narcolepsy is a severe sleep disorder, in which neurons producing orexin/hypocretin in the hypothalamus are destroyed. The core symptoms of narcolepsy are debilitating, extreme sleepiness, cataplexy, and abnormalities in the structure of sleep. Both genetic and epidemiological evidence point towards an autoimmune mechanism in the destruction of orexin/hypocretin neurons. Importantly, the highest environmental risk is seen with influenza-A infection and immunization. However, how the cells are destroyed is currently unknown. In this review we summarize the disease symptoms, and focus on the immunological findings in narcolepsy. We also discuss the environmental and genetic risk factors as well as propose a model for disease development.

Evidence-based update on rosacea comorbidities and their common physiologic pathways

Rosacea is a common chronic inflammatory disease affecting the facial skin whose etiology and pathophysiology are the subject of much investigation. Risk factors include genetic and environmental elements that may predispose individuals to localized inflammation and abnormal neurovascular responses to stimuli. Recent studies have introduced an array of systemic rosacea comorbidities, such as inflammatory bowel disease and neurologic conditions, that can be challenging to synthesize. We critically review the current data behind reported rosacea comorbidities and identify and highlight underrecognized physiologic mediators shared among rosacea and associated comorbidities. This information may be helpful in addressing patient questions about potential systemic implications of rosacea and can serve as a candidate platform for future research to understand rosacea and improve treatments.

Celiac disease: from etiological factors to evolving diagnostic approaches

Celiac disease has advanced from a medical rarity to a highly prevalent disorder. Patients with the disease show varying degrees of chronic inflammation within the small intestine due to an aberrant immune response to the digestion of gliadin found in wheat. As a result, cytokines and antibodies are produced in celiac patients that can be used as specific biomarkers for developing diagnostic tests. This review paper describes celiac disease in terms of its etiological cause, pathological effects, current diagnostic tests based on mucosal biopsy, and the genetic basis for the disease. In addition, it discusses the use of gliadin-induced cytokines, antibodies and autoantibodies as a diagnostic tool for celiac disease. Despite good initial results in terms of sensitivity and specificity, when these immunological tests were used on a large scale, even in combination with genetic testing, the results showed lower predictive value. This review addresses that issue and ends with an outlook on future work required to develop diagnostic tests with greater accuracy in predicting celiac disease in the general public, thus avoiding the need for endoscopy and mucosal biopsy.

Allelic frequencies of the hs1.2 enhancer within the immunoglobulin heavy chain region in Dayton, Ohio patients screened for celiac disease with duodenal biopsy

BACKGROUND

Genetic and environmental factors contribute to the development of celiac disease (CD), but specific genetic predisposing factors remain poorly understood. One candidate is allele 2 of the hs1.2 enhancer within the immunoglobulin heavy chain region. In humans, there are four possible alleles and a previous study of an Italian cohort demonstrated a significantly increased frequency of allele 2 in patients with CD.

AIMS

The purpose of the current study was to determine if a similar association between allele 2 and CD exists in an American population from Dayton, OH.

METHODS

Subjects were screened for CD via esophagogastroduodenoscopy with duodenal biopsy. All biopsies were microscopically scored using a modified Marsh-Oberhuber classification. DNA was isolated from patients' buccal cells for hs1.2 genotype analysis using PCR.

RESULTS

Unlike the Italian cohort, allele 2 frequency was not significantly different in patients with histopathologic evidence of CD compared to patients without such evidence. However, our patient population as a whole demonstrated a significantly increased allele 2 frequency when compared to that previously reported within diverse ethnic populations.

CONCLUSIONS

Since our comparative control patients do not necessarily reflect a healthy control population, an overall increase in allele 2 may reflect an association between allele 2 of the hs1.2 enhancer and a spectrum of gastrointestinal disorders.

Lack of immunogenicity of hydrolysed wheat flour in patients with coeliac disease after a short-term oral challenge

BACKGROUND

A gluten-free diet is currently the only reliable therapeutic strategy that is approved for coeliac disease (CD). For many patients, however, compliance remains inadequate.

AIM

To investigate the immunogenicity of wheat flour that was pre-treated with selected lactobacilli and fungal proteases (hydrolysed wheat gluten) in coeliac patients.

METHODS

The immunogenicity of hydrolysed wheat gluten was evaluated both in vitro in intestinal T cell lines (TCLs) and in vivo in treated CD patients after a short-term gluten challenge. Twenty treated CD patients were enrolled and equally randomised into two groups. The patients ate bread that was prepared with hydrolysed wheat flour or natural wheat flour (10 g of gluten/d for 3 days). The interferon (INF)-γ responses to natural gliadin and a 33-mer peptide were assessed by the enzyme-linked immunospot (ELISPOT) assay on peripheral blood mononuclear cells (PBMCs) both before and 6 days after the start of the challenge.

RESULTS

Hydrolysed wheat was not able to activate the TCLs from the coeliac intestinal mucosa. Consistent with the in vitro results, no significant increase in INF-γ secretion was observed in patients who consumed hydrolysed wheat flour. Conversely, the consumption of natural wheat gluten mobilised INF-γ secreting cells in the blood (P<.05).

CONCLUSIONS

We confirm that fermentation of wheat flour with sourdough lactobacilli and fungal proteases is capable of abolishing the T cell immunogenicity of gluten in coeliac patients. Our data also validate the short-term oral challenge as a useful tool for testing the efficacy of novel therapeutic approaches.

The Role of Oxidative Stress in the Etiopathogenesis of Gluten-sensitive Enteropathy Disease

Background

The objective here is to examine the role of overall oxidative stress in the etiopathogenesis of gluten-sensitive enteropathy disease and its relationship with gluten free diet and autoantibodies.

Methods

Eighty gluten-sensitive enteropathy patients and 80 control group participants were included in the study. As oxidative stress parameters, we researched total antioxidant status (TAS), total oxidant status (TOS), oxidative stress index (OSI), paraoxonase-1 and arylesterase parameters in the serum samples of gluten-sensitive enteropathy patients.

Results

In comparison to the control group, gluten-sensitive enteropathy patients had lower TAS, paraoxonase-1 and arylesterase levels and gluten-sensitive enteropathy patients had considerable TOS and OSI levels. In contrast, patients who agreed to the gluten free eating routine had a higher OSI proportion and patients who did not conform to the gluten free eating regimen had a lower paraoxonase-1 level. An affirming reciprocation was de tected amidst TOS and OSI proportion and gluten-sensitive enteropathy autoantibodies and C-reactive protein levels and a negative correlation was found between arylesterase level and gluten-sensitive enteropathy autoantibodies.

Conclusions

We observed oxidative stress levels to be higher in gluten-sensitive enteropathy patients contrasted with the control group. Oxidative stress level showed differences in gluten-sensitive enteropathy patients depending on gluten diet content and autoantibody positivity. In point of fact, C-reactive protein and gluten-sensitive enteropathy autoantibodies are identified with oxidative anxiety parameters resulting in the possibility that oxidative stress might be successful in the gluten-sensitive enteropathy pathogenesis.

The enteric toxicity of gluten enhances graft-versus-host disease after allogeneic hematopoietic stem cell transplantation

Pro-inflammatory peptides present in wheat and related grains are associated with celiac disease and non-celiac gluten sensitivity. We hypothesize that these peptides induce enteric responses that may exacerbate the gastrointestinal manifestations of graft-versus-host disease after an allogeneic hematopoietic stem cell transplant. Therefore, we propose that a gluten free diet should be tested as a prophylactic and/or therapeutic intervention against gastrointestinal graft-versus-host disease for patients undergoing an allogeneic hematopoietic stem cell transplant.

A B-Cell Gene Signature Correlates With the Extent of Gluten-Induced Intestinal Injury in Celiac Disease

BACKGROUND & AIMS

Celiac disease (CeD) provides an opportunity to study autoimmunity and the transition in immune cells as dietary gluten induces small intestinal lesions.

METHODS

Seventy-three celiac disease patients on a long-term, gluten-free diet ingested a known amount of gluten daily for 6 weeks. A peripheral blood sample and intestinal biopsy specimens were taken before and 6 weeks after initiating the gluten challenge. Biopsy results were reported on a continuous numeric scale that measured the villus-height-to-crypt-depth ratio to quantify gluten-induced intestinal injury. Pooled B and T cells were isolated from whole blood, and RNA was analyzed by DNA microarray looking for changes in peripheral B- and T-cell gene expression that correlated with changes in villus height to crypt depth, as patients maintained a relatively healthy intestinal mucosa or deteriorated in the face of a gluten challenge.

RESULTS

Gluten-dependent intestinal damage from baseline to 6 weeks varied widely across all patients, ranging from no change to extensive damage. Genes differentially expressed in B cells correlated strongly with the extent of intestinal damage. A relative increase in B-cell gene expression correlated with a lack of sensitivity to gluten whereas their relative decrease correlated with gluten-induced mucosal injury. A core B-cell gene module, representing a subset of B-cell genes analyzed, accounted for the correlation with intestinal injury.

CONCLUSIONS

Genes comprising the core B-cell module showed a net increase in expression from baseline to 6 weeks in patients with little to no intestinal damage, suggesting that these individuals may have mounted a B-cell immune response to maintain mucosal homeostasis and circumvent inflammation. DNA microarray data were deposited at the GEO repository (accession number: GSE87629; available: https://www.ncbi.nlm.nih.gov/geo/).

Gliadin-reactive T cells in Italian children from preventCD cohort at high risk of celiac disease

BACKGROUND

Newborns at high risk of celiac disease (CD) were recruited in Italy in the context of the PreventCD study and closely monitored for CD, from 4 months up to a mean age of 8 years at follow-up. The aim of our study was to investigate intestinal T-cell reactivity to gliadin at the first clinical and/or serological signs of CD.

METHODS

Gliadin-reactive T-cell lines were generated from intestinal biopsies of 19 HLA-DQ2-or HLA-DQ8-positive children. At biopsy, 11 children had a diagnosis of acute CD, two of potential CD, and six were non-celiac controls. Immune reactivity was evaluated against gliadin and known immunogenic peptides from α-, γ-, or ω-gliadins. The role of deamidation by transglutaminase (tTG) in determining the immunogenicity of gliadin was also investigated.

RESULTS

Most of the children with CD (either acute or potential) had an inflammatory response to gliadin. Notably, signs of T-cell reactivity to gliadin were also found in some non-celiac subjects, in which IFN-γ responses occurred mainly when regulatory IL-10 and TGF-β cytokines were blocked. Interestingly, PreventCD children reacted to gliadin peptides found active in adult CD patients, and tTG deamidation markedly enhanced gliadin recognition.

CONCLUSIONS

T cells reactive to gliadin can be detected in the intestine of children at high risk of developing CD, in some cases also in the presence of a normal mucosa and negative CD-associated antibodies. Furthermore, children at a very early stage of CD recognize the same gliadin epitopes that are active in adult CD patients. Tissue transglutaminase strongly enhances gluten T-cell immunogenicity in early CD.

Celiac disease: From pathophysiology to treatment

Celiac disease, also known as "celiac sprue", is a chronic inflammatory disorder of the small intestine, produced by the ingestion of dietary gluten products in susceptible people. It is a multifactorial disease, including genetic and environmental factors. Environmental trigger is represented by gluten while the genetic predisposition has been identified in the major histocompatibility complex region. Celiac disease is not a rare disorder like previously thought, with a global prevalence around 1%. The reason of its under-recognition is mainly referable to the fact that about half of affected people do not have the classic gastrointestinal symptoms, but they present nonspecific manifestations of nutritional deficiency or have no symptoms at all. Here we review the most recent data concerning epidemiology, pathogenesis, clinical presentation, available diagnostic tests and therapeutic management of celiac disease.

Genome-wide analysis of complex wheat gliadins, the dominant carriers of celiac disease epitopes

Gliadins, specified by six compound chromosomal loci (Gli-A1/B1/D1 and Gli-A2/B2/D2) in hexaploid bread wheat, are the dominant carriers of celiac disease (CD) epitopes. Because of their complexity, genome-wide characterization of gliadins is a strong challenge. Here, we approached this challenge by combining transcriptomic, proteomic and bioinformatic investigations. Through third-generation RNA sequencing, full-length transcripts were identified for 52 gliadin genes in the bread wheat cultivar Xiaoyan 81. Of them, 42 were active and predicted to encode 25 α-, 11 γ-, one δ- and five ω-gliadins. Comparative proteomic analysis between Xiaoyan 81 and six newly-developed mutants each lacking one Gli locus indicated the accumulation of 38 gliadins in the mature grains. A novel group of α-gliadins (the CSTT group) was recognized to contain very few or no CD epitopes. The δ-gliadins identified here or previously did not carry CD epitopes. Finally, the mutant lacking Gli-D2 showed significant reductions in the most celiac-toxic α-gliadins and derivative CD epitopes. The insights and resources generated here should aid further studies on gliadin functions in CD and the breeding of healthier wheat.

The composition of T cell subtypes in duodenal biopsies are altered in coeliac disease patients

One of the hallmarks of Celiac disease (CD) is intraepithelial lymphocytosis in the small intestine. Until now, investigations to characterize the T cell subpopulations within the epithelial layer have not discriminated between the heterodimeric co-receptor molecule, CD8αβ, and the possibly immunoregulatory CD8αα homodimer molecule. Besides TCRαβ+ CD4+ cells, no other phenotypes have been shown to be gluten-reactive. Using flow cytometry on lymphocytes from duodenal biopsies, we determined that the number of B cells (CD3- CD19+) and the number of CD3+ CD4- CD8- double-negative (DN) T cells were elevated 6–7 fold in children with CD. We next isolated and quantified intraepithelial lymphocytes (IELs) from biopsies obtained from patients (both children and adults) with CD, potential CD and non-CD controls. Flow cytometric analysis of the duodenal T cell subpopulations was performed including the markers TCRαβ, TCRγδ, CD4, CD8α and CD8β. Proportions of γδ T cells and CD8αβ⁺ cells among IELs were increased in CD patients, whereas proportions of CD4+ CD8αα+ and CD4+ single-positive T cells were decreased. Additionally, two gluten-reactive T cell lines (TCLs) derived from CD biopsies were analyzed for changes in proportions of T cell subsets before and after gluten stimulation. In a proliferation assay, dividing cells were tracked with carboxyfluorescein succinimidyl ester (CFSE), and both αβ and γδ T cells proliferated in response to gluten. Changes in duodenal T cell subpopulations in potential CD patients followed the same pattern as for CD patients, but with less pronounced effect.

Immunogenetic Pathogenesis of Celiac Disease and Non-celiac Gluten Sensitivity

Celiac disease is the most common oral intolerance in Western countries. It results from an immune response towards gluten proteins from certain cereals in genetically predisposed individuals (HLA-DQ2 and/or HLA-DQ8). Its pathogenesis involves the adaptive (HLA molecules, transglutaminase 2, dendritic cells, and CD4(+) T-cells) and the innate immunity with an IL-15-mediated response elicited in the intraepithelial compartment. At present, the only treatment is a permanent strict gluten-free diet (GFD). Multidisciplinary studies have provided a deeper insight of the genetic and immunological factors and their interaction with the microbiota in the pathogenesis of the disease. Similarly, a better understanding of the composition of the toxic gluten peptides has improved the ways to detect them in food and drinks and how to monitor GFD compliance via non-invasive approaches. This review, therefore, addresses the major findings obtained in the last few years including the re-discovery of non-celiac gluten sensitivity.

Novel approaches for enzymatic gluten degradation to create high-quality gluten-free products

Celiac disease (CD), a chronic enteropathy of the small intestine caused by ingestion of gluten, is one of the most prevalent food hypersensitivities worldwide. The essential treatment is a strict lifelong gluten-free diet based on the avoidance of gluten-containing products from wheat, rye, barley and, in rare cases, oats. Products made from naturally gluten-free raw materials often have inferior nutritional, textural and sensory properties compared to the corresponding gluten-containing products. Therefore, the incorporation of wheat, rye and barley flours after efficient removal of the harmful component gluten into gluten-free products would be beneficial. Gluten modification resulting in decreased CD-immunoreactivity may be achieved via the formation of crosslinks using microbial transglutaminase. To effectively eliminate CD-immunoreactivity, plant, fungal, bacterial, animal or engineered peptidases are capable of degrading gluten proteins and peptides into harmless fragments. The application of peptidases from germinated cereal grains, fungal peptidases and/or lactic acid bacteria during food processing yielded high-quality sourdough wheat breads, pasta, wheat starch and bran, rye products and beer, all with gluten contents below the Codex Alimentarius threshold of 20mg/kg for gluten-free products. As with all gluten-free products, the legislative compliance of such treated materials needs to be monitored closely. Provided that all safety requirements are met, gluten-containing raw materials treated in an adequate way to remove CD-active gluten fragments may be used together with naturally gluten-free ingredients to create an extended choice of high-quality gluten-free products.

Transglutaminase 2 strongly binds to an extracellular matrix component other than fibronectin via its second C-terminal beta-barrel domain

Transglutaminase 2 (TG2) is a ubiquitous crosslinking enzyme present in both intra- and extracellular in many cell types and tissues. TG2 is upregulated upon cellular stress or injury, and extracellular TG2 is implicated in several human diseases, including celiac disease. However, incomplete knowledge about extracellular TG2 biology limits our understanding of how TG2 is involved in disease. Here, we demonstrate that binding of TG2 to the ECM of small intestinal tissue sections is the sum of binding to fibronectin (FN) via its N-terminal domain and binding to an abundant, novel extracellular matrix (ECM) interaction partner via its second C-terminal beta-barrel domain. The latter interaction dominates and gives rise to the characteristic reticular staining pattern of extracellular TG2. Of relevance for celiac disease, we show that self-multimerized TG2 does not efficiently deposit in the intestinal ECM, and TG2 complexes may thus become free-floating antigens in tissues in contrast to monomeric TG2 that would readily become sequestered by the ECM. Upon injection of monoclonal antibody targeting the FN-binding site, we observe antibody deposition on extracellular TG2 in cryosections, suggesting that the FN-binding site of TG2 is exposed in vivo. This would explain how and why celiac autoantibodies recognizing the FN-binding site of TG2 can bind TG2 in vitro, in situ as well as in vivo.

Transglutaminase 2-specific coeliac disease autoantibodies induce morphological changes and signs of inflammation in the small-bowel mucosa of mice

Coeliac disease is hallmarked by an abnormal immune reaction against ingested wheat-, rye- and barley-derived gluten and the presence of transglutaminase 2 (TG2)-targeted autoantibodies. The small-bowel mucosal damage characteristic of the disorder develops gradually from normal villus morphology to inflammation and finally to villus atrophy with crypt hyperplasia. Patients with early-stage coeliac disease have TG2-autoantibodies present in serum and small-intestinal mucosa and they may already suffer from abdominal symptoms before the development of villus atrophy. Previously, we have shown that intraperitoneal injections of coeliac patient-derived sera or purified immunoglobulin fraction into mice induce a condition mimicking early-stage coeliac disease. In the current study, we sought to establish whether recombinantly produced patient-derived TG2-targeted autoantibodies are by themselves sufficient for the development of such an experimentally induced condition in immune-compromised mice. Interestingly, mice injected with coeliac patient TG2-antibodies had altered small-intestinal mucosal morphology, increased lamina propria cellular infiltration and disease-specific autoantibodies deposited in the small bowel, but did not evince clinical features of the disease. Thus, coeliac patient-derived TG2-specific autoantibodies seem to be sufficient for the induction of subtle small-bowel mucosal alterations in mice, but the development of clinical features probably requires additional factors such as other antibody populations relevant in coeliac disease.

TCR sequencing of single cells reactive to DQ2.5-glia-α2 and DQ2.5-glia-ω2 reveals clonal expansion and epitope-specific V-gene usage

CD4+ T cells recognizing dietary gluten epitopes in the context of disease-associated human leukocyte antigen (HLA)-DQ2 or HLA-DQ8 molecules are the key players in celiac disease pathogenesis. Here, we conducted a large-scale single-cell paired T-cell receptor (TCR) sequencing study to characterize the TCR repertoire for two homologous immunodominant gluten epitopes, DQ2.5-glia-α2 and DQ2.5-glia-ω2, in blood of celiac disease patients after oral gluten challenge. Despite sequence similarity of the epitopes, the TCR repertoires are unique but shared several overall features. We demonstrate that clonally expanded T cells dominate the T-cell responses to both epitopes. Moreover, we find V-gene bias of TRAV26, TRAV4, and TRBV7 in DQ2.5-glia-α2 reactive TCRs, while DQ2.5-glia-ω2 TCRs displayed significant bias toward TRAV4 and TRBV4. The knowledge that antigen-specific TCR repertoire in chronic inflammatory diseases tends to be dominated by a few expanded clones that use the same TCR V-gene segments across patients is important information for HLA-associated diseases where the antigen is unknown.

High-risk genotypes HLA-DR3-DQ2/DR3-DQ2 and DR3-DQ2/DR4-DQ8 in co-occurrence of type 1 diabetes and celiac disease

Shared susceptibility alleles in the HLA region contribute to the co-existence of type 1 diabetes (T1D) and celiac disease (CD). The aim of our study was to identify HLA genotype variations that influence co-occurrence of T1D and CD (T1D + CD) and the order of their onset. Totally 244 patients, 67 with T1D, 68 with CD and 69 with T1D + CD, (split into "T1D first" and "CD first"), were analyzed. Control group consisted of 130 healthy unrelated individuals. Two-tailed Fisher's exact test was used for statistical analysis. The genetic background of Slovenian CD patients resembled more northern than southern European populations with DR3-DQ2/DR3-DQ2 (odds ratio [OR] = 19.68) conferring the highest risk. The T1D + CD was associated with DR3-DQ2/DR3-DQ2 (OR = 45.53) and even more with DR3-DQ2/DR4-DQ8 (OR = 93.76). DR3-DQ2/DR7-DQ2 played a neutral role in susceptibility for T1D + CD. The order of the onset of T1D or CD in patients with co-occurring diseases was not influenced by HLA risk genotype profile. DR3-DQ2/DR3-DQ2 was associated with an increased risk for developing CD in patients with T1D, whereas patients with CD carrying DR3-DQ2/DR4-DQ8 were at higher risk for developing T1D. In addition to other genetic factors including HLA class I alleles present on DR3-DQ2 extended haplotype, the second extended haplotype may moderate the risk for T1D + CD conferred by DR3-DQ2. Our results suggested that individuals carrying high-risk genotypes DR3-DQ2/DR3-DQ2 or DR3-DQ2/DR4-DQ8 would more likely develop both T1D and CD than either disease alone.

Understanding Celiac Disease by Genomics

Celiac disease (CeD) is a complex immune-mediated disease. Genetic studies have implicated 43 predisposing loci that collectively explain some 50% of the genetic variance in CeD. More than ∼90% of CeD-associated single nucleotide polymorphisms (SNPs) localize to the non-coding genome, which we need to better understand to translate genetic knowledge into clinical practice. New genomic technologies and resources are permitting a systematic analysis of the functional elements in the non-coding part of the genome. Here we explain how investigating the regulatory and epigenomic landscape will help to pinpoint the cell types involved in CeD, and the driver genes and gene regulatory networks that are affected by CeD-associated SNPs.

The Spectrum of Differences between Childhood and Adulthood Celiac Disease

An old saying states that ''children are not little adults" and this certainly holds true for celiac disease, as there are many peculiar aspects regarding its epidemiology, diagnosis, clinical presentations, associated diseases, and response to treatment in pediatric compared to adult populations, to such an extent that it merits a description of its own. In fact, contrary to the past when it was thought that celiac disease was a disorder predominantly affecting childhood and characterized by a malabsorption syndrome, nowadays it is well recognized that it affects also adult and elderly people with an impressive variability of clinical presentation. In general, the clinical guidelines for diagnosis recommend starting with specific serologic testing in all suspected subjects, including those suffering from extraintestinal related conditions, and performing upper endoscopy with appropriate biopsy sampling of duodenal mucosa in case of positivity. The latter may be omitted in young patients showing high titers of anti-transglutaminase antibodies. The subsequent management of a celiac patient differs substantially depending on the age at diagnosis and should be based on the important consideration that this is a lifelong condition.