The immunology of gluten sensitivity: beyond the gut

Differential immune responses behind different celiac disease manifestations

In celiac disease (CeD), dietary gluten serves as the driver for a comparatively well characterized small bowel mucosal immune response that generally results in small bowel mucosal villous atrophy and crypt hyperplasia along with a disease-specific transglutaminase 2 (TG2) targeting autoantibody response. Individuals with positive TG2 autoantibodies but normal small intestinal mucosal morphology are regarded at increased risk of developing CeD and represent patients with potential CeD. The removal of gluten from the diet leads to disappearance of the autoantibodies and normalization of the mucosal architecture in most cases. However, refractory CeD patients deviate from this dogma as they present with abnormal T cell compartment, persistent symptoms and villous atrophy despite a strict gluten-free diet. The heterogeneity of CeD presentation is further diversified by varying symptomatology. Gastrointestinal symptoms are the most canonical signs of CeD, and they include for instance diarrhea, vomiting, constipation and abdominal pain. Yet, a great portion of the patients manifest the disease at extraintestinal sites such as skin, musculoskeletal system or neuronal tissues. Beyond the involvement of various transglutaminase autoantibodies, the detailed immune mechanisms contributing to the development of these manifestations remains elusive, though. This review highlights the current understanding of the immunological differences in various manifestations of CeD. As the immunological basis of the different CeD phenotypes is at present insufficiently understood, more research on the subject is warranted before such data could be maximally applied to clinical practice.

Influence of dietary patterns in the pathophysiology of Huntington's Disease: A literature review

Huntington's disease (HD), a rare autosomal dominant neurodegenerative disease, causes the gradual deterioration of neurons in the basal ganglia, specifically in the striatum. HD displays a wide range of symptoms, from motor disturbances such as chorea, dystonia, and bradykinesia to more debilitating symptoms such as cognitive decline, behavioral abnormalities, and psychiatric disturbances. Current research suggests the potential use of dietary interventions as viable strategies for slowing the progression of HD. Most notably, the Mediterranean, vegan, carnivore, paleo, and ketogenic diets have gained attention due to their hypothesized impact on neuroprotection and symptomatic modulation in various neurodegenerative disorders. Despite substantial nutritional differences among these diets, they share a fundamental premise-that dietary factors have an influential impact in modifying pertinent biological pathways linked to neurodegeneration. Understanding the intricate interactions between these dietary regimens and HD pathogenesis could open avenues for personalized interventions tailored to the individual's specific needs and genetic background. Ultimately, elucidating the multifaceted effects of these diets on HD offers a promising framework for developing comprehensive therapeutic approaches that integrate dietary strategies with conventional treatments.

Celiac Disease and Neurological Manifestations: From Gluten to Neuroinflammation

Celiac disease (CD) is a complex multi-organ disease with a high prevalence of extra-intestinal involvement, including neurological and psychiatric manifestations, such as cerebellar ataxia, peripheral neuropathy, epilepsy, headache, cognitive impairment, and depression. However, the mechanisms behind the neurological involvement in CD remain controversial. Recent evidence shows these can be related to gluten-mediated pathogenesis, including antibody cross-reaction, deposition of immune-complex, direct neurotoxicity, and in severe cases, vitamins or nutrients deficiency. Here, we have summarized new evidence related to gut microbiota and the so-called "gut-liver-brain axis" involved in CD-related neurological manifestations. Additionally, there has yet to be an agreement on whether serological or neurophysiological findings can effectively early diagnose and properly monitor CD-associated neurological involvement; notably, most of them can revert to normal with a rigorous gluten-free diet. Moving from a molecular level to a symptom-based approach, clinical, serological, and neurophysiology data might help to disentangle the many-faceted interactions between the gut and brain in CD. Eventually, the identification of multimodal biomarkers might help diagnose, monitor, and improve the quality of life of patients with "neuroCD".

A Breakdown of Immune Tolerance in the Cerebellum

Cerebellar dysfunction can be associated with ataxia, dysarthria, dysmetria, nystagmus and cognitive deficits. While cerebellar dysfunction can be caused by vascular, traumatic, metabolic, genetic, inflammatory, infectious, and neoplastic events, the cerebellum is also a frequent target of autoimmune attacks. The underlying cause for this vulnerability is unclear, but it may be a result of region-specific differences in blood–brain barrier permeability, the high concentration of neurons in the cerebellum and the presence of autoantigens on Purkinje cells. An autoimmune response targeting the cerebellum—or any structure in the CNS—is typically accompanied by an influx of peripheral immune cells to the brain. Under healthy conditions, the brain is protected from the periphery by the blood–brain barrier, blood–CSF barrier, and blood–leptomeningeal barrier. Entry of immune cells to the brain for immune surveillance occurs only at the blood-CSF barrier and is strictly controlled. A breakdown in the barrier permeability allows peripheral immune cells uncontrolled access to the CNS. Often—particularly in infectious diseases—the autoimmune response develops because of molecular mimicry between the trigger and a host protein. In this review, we discuss the immune surveillance of the CNS in health and disease and also discuss specific examples of autoimmunity affecting the cerebellum.

Measures of gluten-related reactivity in children with autism spectrum disorders in the absence of overt gastrointestinal symptoms: a pilot study from the United Arab Emirates

Objectives

The aetiology of autism spectrum disorder (ASD) is multifactorial, sometimes genetic, and may be associated with abnormal immunological responses to peptides from proteins such as gluten. These peptides may cross the blood-brain barrier and affect neurotransmission, resulting in behavioural symptoms consistent with ASD. The aim of this study was to screen for markers of gluten-related immune reactivity in the absence of overt gastrointestinal symptoms in patients with ASD in the United Arab Emirates, a country associated with a high prevalence of ASD but lacking this type of research.

Methods

Patients diagnosed with ASD (using Diagnostic and Statistical Manual of Mental Disorders-IV-based criteria and Autism Diagnostic Observational Schedules) were compared with controls, regarding anti-tissue transglutaminase (tTG) immunoglobulin (Ig) A and anti-deamidated gliadin peptide (DGP) IgA levels.

Results

Sixty-six patients with ASD and 101 controls were included. Patients with ASD showed statistically significant lower anti-DGP IgA levels, but no significant difference in anti-tTG IgA levels, versus healthy controls. Correlations between immunological data and clinical symptoms were synergistic, but not statistically significant.

Conclusion

ASD may be associated with reduced levels of anti-DGP IgA.

Neurological Manifestations of Neuropathy and Ataxia in Celiac Disease: A Systematic Review

Celiac disease (CD) is an immune-mediated gastrointestinal disorder driven by innate and adaptive immune responses to gluten. Patients with CD are at an increased risk of several neurological manifestations, frequently peripheral neuropathy and gluten ataxia. A systematic literature review of the most commonly reported neurological manifestations (neuropathy and ataxia) associated with CD was performed. MEDLINE, Embase, the Cochrane Library, and conference proceedings were systematically searched from January 2007 through September 2018. Included studies evaluated patients with CD with at least one neurological manifestation of interest and reported prevalence, and/or incidence, and/or clinical outcomes. Sixteen studies were included describing the risk of gluten neuropathy and/or gluten ataxia in patients with CD. Gluten neuropathy was a neurological manifestation in CD (up to 39%) in 13 studies. Nine studies reported a lower risk and/or prevalence of gluten ataxia with a range of 0%⁻6%. Adherence to a gluten-free diet appeared to improve symptoms of both neuropathy and ataxia. The prevalence of gluten neuropathy and gluten ataxia in patients with CD varied in reported studies, but the increased risk supports the need for physicians to consider CD in patients with ataxia and neurological manifestations of unknown etiology.

Coeliac disease and gastrointestinal symptom screening in adult first-degree relatives

BACKGROUND AND AIM

The first-degree relatives (FDRs) of patients with coeliac disease are the main risk group for disease development. The study aims to evaluate the screening strategy in FDRs with negative coeliac serology based on human leukocyte antigen (HLA) genotyping, followed by duodenal biopsy, and to analyze the prevalence of gastrointestinal symptoms and the influence of gluten intake.

METHODS

Adult FDRs with negative coeliac serology were invited to participate (n = 205), and a total of 139 completed the study protocol. HLA genotyping, transglutaminase antibody assessment, and duodenal biopsy were performed. Symptomatology was assessed using questionnaires during the various phases of dietary modification (baseline diet, gluten-free diet, and gluten overload).

RESULTS

The study included 139 participants (mean age, 42 years; 53.2% women). HLA-DQ2/8 was positive in 78.4% of the participants (homozygous, 15.1%; heterozygous, 63.3%). Histopathological alterations were noted in 37.1% of participants who underwent duodenal biopsy (Marsh I, 32.7%; Marsh IIIa, 4.4%). At baseline, symptoms were observed in 45.7% of the participants, and the proportion decreased to 24.5% after the gluten-free diet (P < 0.001). Symptoms were not associated with the presence of histological alterations or genetic risk. However, younger age (odds ratio [OR] = 0.91), female sex (OR = 2.9), and the presence of autoimmune disorders (OR = 2.8) were independently associated with a significant symptom response to the gluten-free diet.

CONCLUSIONS

Duodenal lymphocytosis and atrophy are frequently noted in FDRs, despite negative serological markers. In addition, gastrointestinal symptoms are commonly present and associated with gluten intake regardless of the histological pathology.

Coeliac disease and psychiatric comorbidity: epidemiology, pathophysiological mechanisms, quality-of-life, and gluten-free diet effects

Coeliac Disease (CD) is an autoimmune disease in which an environmental factor, gluten, triggers a pathological reaction. It results in intra- and entra-intestinal manifestations of disease, including, most frequently, diarrhoea, weight loss, and anaemia. CD occurs in ∼1% of the western population, being one of the most common autoimmune lifelong disorders, and may present with a variety of psychiatric comorbidities. Psychiatric comorbidity in CD often complicates the diagnosis, reduces the quality-of-life, and worsens the prognosis of affected patients. This review summarizes the epidemiological studies that underline this connection, and focuses on the potential mechanisms related to this comorbility, such as nutritional deficiencies, immune responses, interference in brain processes, and dysfunctions in the gut-brain axis. Factors that play a central role on patients' quality of life, psychological well-being and adherence are presented. Finally, evidence of regression in psychiatric symptoms following the introduction of a gluten-free diet is underlined as well.

Sensory Neuronopathies

PURPOSE OF REVIEW

The sensory neuronopathies are sensory-predominant polyneuropathies that result from damage to the dorsal root and trigeminal sensory ganglia. This review explores the various causes of acquired sensory neuronopathies, the approach to diagnosis, and treatment.

RECENT FINDINGS

Diagnostic criteria have recently been published and validated to allow differentiation of sensory neuronopathies from other polyneuropathies. On the basis of serial electrodiagnostic studies, the treatment window for the acquired sensory neuronopathies has been identified as approximately 8 months. If treatment is initiated within 2 months of symptom onset, there is a better opportunity for improvement of the patient's condition. Even though sensory neuronopathies are rare, significant progress has been made regarding characterization of their clinical, electrophysiologic, and imaging features. This does not hold true, however, for treatment. There have been no randomized controlled clinical trials to guide management of these diseases, and a standard treatment approach remains undetermined.

Gluten related illnesses and severe mental disorders: a comprehensive review

The putative role of gluten in the pathophysiology of severe mental illnesses remains uncertain and there is doubt about the possible benefit of gluten-free diets for individuals affected by psychosis and mood disorders. The objective of this review was to summarize the findings linking gluten related conditions to pathophysiological substrates implicated in schizophrenia and mood disorders and review the evidences of potential benefits of glute-free diets in these populations. A literature search was conducted within PubMed and Scielo databases including references from inception until March 1st 2017. The strategy search was to use the key words "gluten", "celiac disease", "wheat", "bipolar disorder", "mood disorders", "psychosis", "schizophrenia", "depression". In the review about the potential efficacy of gluten-free diets in severe mental illnesses, we included only studies with original data, including cross sectional and longitudinal studies and clinical trials. Book chapters, review articles and meta-analysis and republished data were excluded. Although the current available evidences suggest that people with celiac disease or gluten allergy could have a slightly higher risk of schizophrenia and mood disorders compared to the general population, the literature review reveals significant inaccuracies in the data. There is insufficient evidence to recommend gluten-free diets for populations with psychosis and mood disorders.

Circular dichroism and electron microscopy studies in vitro of 33-mer gliadin peptide revealed secondary structure transition and supramolecular organization

Gliadin, a protein present in wheat, rye, and barley, undergoes incomplete enzymatic degradation during digestion, producing an immunogenic 33-mer peptide, LQLQPF(PQPQLPY)3 PQPQPF. The special features of 33-mer that provoke a break in its tolerance leading to gliadin sensitivity and celiac disease remains elusive. Herein, it is reported that 33-mer gliadin peptide was not only able to fold into polyproline II secondary structure but also depending on concentration resulted in conformational transition and self-assembly under aqueous condition, pH 7.0. A 33-mer dimer is presented as one initial possible step in the self-assembling process obtained by partial electrostatics charge distribution calculation and molecular dynamics. In addition, electron microscopy experiments revealed supramolecular organization of 33-mer into colloidal nanospheres. In the presence of 1 mM sodium citrate, 1 mM sodium borate, 1 mM sodium phosphate buffer, 15 mM NaCl, the nanospheres were stabilized, whereas in water, a linear organization and formation of fibrils were observed. It is hypothesized that the self-assembling process could be the result of the combination of hydrophobic effect, intramolecular hydrogen bonding, and electrostatic complementarity due to 33-mer's high content of proline and glutamine amino acids and its calculated nonionic amphiphilic character. Although, performed in vitro, these experiments have revealed new features of the 33-mer gliadin peptide that could represent an important and unprecedented event in the early stage of 33-mer interaction with the gut mucosa prior to onset of inflammation. Moreover, these findings may open new perspectives for the understanding and treatment of gliadin intolerance disorders.

Self-assembly of 33-mer gliadin peptide oligomers

The 33-mer gliadin peptide, LQLQPF(PQPQLPY)3PQPQPF, is a highly immunogenic peptide involved in celiac disease and probably in other immunopathologies associated with gliadin. Herein, dynamic light scattering measurements showed that 33-mer, in the micromolar concentration range, forms polydisperse nano- and micrometer range particles in aqueous media. This behaviour is reminiscent of classical association of colloids and we hypothesized that the 33-mer peptide self-assembles into micelles that could be the precursors of 33-mer oligomers in water. Deposition of 33-mer peptide aqueous solution on bare mica generated nano- and microstructures with different morphologies as revealed by atomic force microscopy. At 6 μM, the 33-mer is organised in isolated and clusters of spherical nanostructures. In the 60 to 250 μM concentration range, the spherical oligomers associated mainly in linear and annular arrangements and structures adopting a "sheet" type morphology appeared. At higher concentrations (610 μM), mainly filaments and plaques immersed in a background of nanospherical structures were detected. The occurrence of different morphologies of oligomers and finally the filaments suggests that the unique specific geometry of the 33-mer oligomers has a crucial role in the subsequent condensation and organization of their fractal structures into the final filaments. The self-assembly process on mica is described qualitatively and quantitatively by a fractal diffusion limited aggregation (DLA) behaviour with the fractal dimension in the range of 1.62 ± 0.02 to 1.73 ± 0.03. Secondary structure evaluation of the oligomers by Attenuated Total Reflection FTIR spectroscopy (ATR-FTIR) revealed the existence of a conformational equilibrium of self-assembled structures, from an extended conformation to a more folded parallel beta elongated structures. Altogether, these findings provide structural and morphological information about supramolecular organization of the 33-mer peptide, which might offer new perspectives for the understanding and treatment of gliadin intolerance disorders.

Portable gliadin-immunochip for contamination control on the food production chain

Celiac disease (CD) is one of the most common digestive disorders caused by an abnormal immune reaction to gluten. So far there are no available therapies, the only solution is a strict gluten-free diet, which however could be very challenging as gluten can be hidden in many food products. Furthermore an additional problem is related to cross-contamination of nominal gluten-free foods with gluten-based ones during manufacturing. Here we propose a lab on chip platform as a powerful tool to help food manufacturers to evaluate the real amount of gluten in their products by an accurate in-situ control of the production chain and maybe to specify the real gluten content in packages labeling. Our portable gliadin-immunochips, based on an electrochemical impedance spectroscopy transduction method, were first calibrated and then validated for both liquid and solid food matrixes by analyzing different beers and flours. The high specificity of our assay was also demonstrated by performing control experiments on rice and potatoes flours containing prolamin-like proteins. We achieved limit of quantification of 0.5 ppm for gliadin that is 20 times lower than the worldwide limit established for gluten-free food while the method of analysis is faster and cheaper than currently employed ELISA-based methods. Moreover our results on food samples were validated through a mass spectrometry standard analysis.

Celiac and non-celiac gluten sensitivity: a review on the association with schizophrenia and mood disorders

An association between many psychiatric and gluten-related disorders has been known for some time. In the case of schizophrenia and mood disorders, the major psychiatric disorders, there is much evidence, not without contradictions, of a possible association between schizophrenia and celiac disease. The association between mood disorders and gluten-related disorders, especially celiac disease, has only been studied for depression, often coupled with anxiety, and very recently for bipolar disorder. Since non-celiac gluten sensitivity is now known to be different from celiac disease, many studies have shown that gluten sensitivity is also associated with major psychiatric disorders. Here we review the literature on the association between schizophrenia/mood disorders and celiac disease/gluten sensitivity, pointing out the differences between these associations.

Prevalence of serum celiac antibody in patients with IBD in Japan

BACKGROUND

Although the incidence of inflammatory bowel diseases (IBD) in Japan has increased, the prevalence of celiac disease is considered very low with the lowest genetic disposition. IBD is reported as the most common comorbidity because of the high positive rate of serological celiac markers. The aim of this study was to examine the current incidence of celiac disease, especially in IBD patients in Japan, where both wheat consumption and incidence of IBD have increased.

METHODS

A total of 172 patients with IBD and 190 controls in Japan were screened for serum antibody of tissue transglutaminase and deaminated gliadin peptide. In sero-positive patients, HLA testing and upper gastrointestinal endoscopy with duodenal biopsy was performed. Some of the sero-positive patients started a gluten-restricted or unrestricted diet, and serological change was determined.

RESULTS

The positivity of both serum antibodies was significantly higher in IBD and correlated with disease activity. However, no biopsy-defined or HLA-defined true celiac disease was found. A decrease in serum antibody titers was observed with a gluten-restricted diet.

CONCLUSIONS

Despite the increased incidence of IBD and high positivity for serum celiac antibody in Japanese IBD patients, no true-positive celiac disease was noted, suggesting the presence of gluten intolerance in these populations.

Antibodies as predictors of autoimmune diseases and cancer

BACKGROUND

Autoantibodies targeted against a variety of self-antigens are detected in autoimmune diseases and cancer. Emerging evidence has suggested the involvement of environmental factors such as infections and xenobiotics, and some dietary proteins and their antibodies in the pathogenesis of many autoimmune diseases. These antibodies appear in the blood years before presentation of symptoms in various disorders. Therefore, these antibodies may be used as biomarkers for early detection of various diseases.

OBJECTIVE

To provide an overview of antibody arrays that are measured against different human tissue antigens, crossreactive epitopes of infectious agents, dietary proteins, and haptenic chemicals in autoimmune diseases and cancer.

METHOD

Microarray analysis of antigen-antibody reaction.

CONCLUSION

The application of these antibody arrays to human autoimmune disease is expanding and is allowing for the identification of patterns or antibody signatures, thus establishing the premises for increased sensitivity and specificity of prediction, as well as positive predictive values. The presence of these antibodies would not necessarily mean that a patient would definitely become sick but may give a percentage of risk for different conditions that may develop over future months or years. Using this high-throughput microarray method, it is possible to screen rapidly for dozens of autoantibodies at low cost. This is an important factor in the implementation of autoantibody testing as a routine part of medical examinations.

The irritable bowel syndrome-celiac disease connection

Irritable bowel syndrome (IBS) is a prevalent functional gastrointestinal disorder that has a significant impact on quality of life and health care resources. Celiac disease (CD), a gluten-sensitive enteropathy, can be mistaken for IBS. This article discusses the connection between IBS and CD and the new concept of nonceliac gluten sensitivity (NCGS). NCGS may occur in the presence of a normal or near-normal small bowel biopsy. Some patients with IBS without CD may derive symptomatic benefit from a gluten-free diet. Future research could facilitate a significant impact on the quality of life in this potential subgroup of patients.

Emerging concepts: from coeliac disease to non-coeliac gluten sensitivity

The rise in gluten consumption over time has led to the increasing recognition of coeliac disease (CD) with associated complications. However, only recently has there been an appreciation that the spectrum of gluten-related disorders is greater than just CD, which may explain the growing global popularity in gluten-free products. Current literature suggests that a newly recognised clinical entity in the form of non-coeliac gluten sensitivity (NCGS) may be the most common gluten-related disorder encountered by healthcare professionals, although its exact prevalence is as yet unknown. This article will review the historical relationship between mankind and gluten as well as the progressive recognition that it is possible for gluten to have a deleterious effect on our health. To this effect we discuss the prevalence, diagnosis and complications of CD including the benefits derived from a gluten-free diet (GFD). Finally, we discuss our current understanding of NCGS, in addition to highlighting the need for further research to determine the extent, clinicopathological features and serological biomarkers to help recognise this emerging condition in clinical practice.

Neurologic and psychiatric manifestations of celiac disease and gluten sensitivity

Celiac Disease (CD) is an immune-mediated disease dependent on gluten (a protein present in wheat, rye or barley) that occurs in about 1% of the population and is generally characterized by gastrointestinal complaints. More recently the understanding and knowledge of gluten sensitivity (GS), has emerged as an illness distinct from celiac disease with an estimated prevalence 6 times that of CD. Gluten sensitive people do not have villous atrophy or antibodies that are present in celiac disease, but rather they can test positive for antibodies to gliadin. Both CD and GS may present with a variety of neurologic and psychiatric co-morbidities, however, extraintestinal symptoms may be the prime presentation in those with GS. However, gluten sensitivity remains undertreated and underrecognized as a contributing factor to psychiatric and neurologic manifestations. This review focuses on neurologic and psychiatric manifestations implicated with gluten sensitivity, reviews the emergence of gluten sensitivity distinct from celiac disease, and summarizes the potential mechanisms related to this immune reaction.

Sensory neuronopathy and autoimmune diseases

Sensory neuronopathies (SNs) are a specific subgroup of peripheral nervous system diseases characterized by primary degeneration of dorsal root ganglia and their projections. Multifocal sensory symptoms often associated to ataxia are the classical features of SN. Several different etiologies have been described for SNs, but immune-mediated damage plays a key role in most cases. SN may herald the onset of some systemic autoimmune diseases, which further emphasizes how important the recognition of SN is in clinical practice. We have thus reviewed available clinical, neurophysiological, and therapeutic data on autoimmune disease-related SN, namely, in patients with Sjögren's syndrome, autoimmune hepatitis, and celiac disease.

Immune-mediated acquired ataxias

The cerebellum, and in particular the Purkinje cells within it, appear to be a frequent immunological target in the context of some systemic diseases. This is perhaps more often the case with the cerebellum by comparison to other structures within the central nervous system. This observation may relate to the fact that the cerebellum is one of the largest, oldest, and most structurally conserved structures in the vertebrate nervous system and/or that Purkinje cells possess good and multiple antigenic targets. Immune-mediated ataxias include paraneoplastic cerebellar degeneration and post-infective cerebellitis, but these will be discussed elsewhere. This chapter covers in detail the epidemiology, clinical characteristics, pathophysiology, and treatment of some other examples of immune-mediated ataxias, including gluten ataxia and ataxia associated with anti-GAD antibodies. There is particular emphasis on gluten ataxia as this is one of the commonest immune-mediated cerebellar ataxias and one of the few ataxias that are potentially treatable. The chapter also introduces the concept of primary autoimmune cerebellar ataxia as a form of organ-specific autoimmune disease for the first time. The pathophysiology leading to cerebellar damage, loss of Purkinje cells, and the development of ataxia remains speculative, but existing clues are discussed in detail.

Gluten causes gastrointestinal symptoms in subjects without celiac disease: a double-blind randomized placebo-controlled trial

OBJECTIVES

Despite increased prescription of a gluten-free diet for gastrointestinal symptoms in individuals who do not have celiac disease, there is minimal evidence that suggests that gluten is a trigger. The aims of this study were to determine whether gluten ingestion can induce symptoms in non-celiac individuals and to examine the mechanism.

METHODS

A double-blind, randomized, placebo-controlled rechallenge trial was undertaken in patients with irritable bowel syndrome in whom celiac disease was excluded and who were symptomatically controlled on a gluten-free diet. Participants received either gluten or placebo in the form of two bread slices plus one muffin per day with a gluten-free diet for up to 6 weeks. Symptoms were evaluated using a visual analog scale and markers of intestinal inflammation, injury, and immune activation were monitored.

RESULTS

A total of 34 patients (aged 29-59 years, 4 men) completed the study as per protocol. Overall, 56% had human leukocyte antigen (HLA)-DQ2 and/or HLA-DQ8. Adherence to diet and supplements was very high. Of 19 patients (68%) in the gluten group, 13 reported that symptoms were not adequately controlled compared with 6 of 15 (40%) on placebo (P=0.0001; generalized estimating equation). On a visual analog scale, patients were significantly worse with gluten within 1 week for overall symptoms (P=0.047), pain (P=0.016), bloating (P=0.031), satisfaction with stool consistency (P=0.024), and tiredness (P=0.001). Anti-gliadin antibodies were not induced. There were no significant changes in fecal lactoferrin, levels of celiac antibodies, highly sensitive C-reactive protein, or intestinal permeability. There were no differences in any end point in individuals with or without DQ2/DQ8.

CONCLUSIONS

"Non-celiac gluten intolerance" may exist, but no clues to the mechanism were elucidated.

White matter lesions suggestive of amyotrophic lateral sclerosis attributed to celiac disease

CD is an autoimmune-mediated disorder of the gastrointestinal tract. Initial symptom presentation is variable and can include neurologic manifestations that may comprise ataxia, neuropathy, dizziness, epilepsy, and cortical calcifications rather than gastrointestinal-hindering diagnosis and management. We present a case of a young man with progressive neurologic symptoms and brain MR imaging findings worrisome for ALS. During the diagnostic work-up, endomysium antibodies were discovered, and CD was confirmed by upper gastrointestinal endoscopy with duodenal biopsies. MR imaging findings suggestive of ALS improved after gluten-free diet institution.

Novel therapeutic targets for autism

Autism spectrum disorders (ASDs) are pervasive neurodevelopmental disorders, diagnosed in early childhood when acquired skills are lost or the acquisition of new skills becomes delayed. ASDs are associated with varying degrees of dysfunctional communication and social skills, in addition to repetitive and stereotypic behaviors. The diagnosis has increased considerably to approximately one in 180 people, but it is not clear whether this is because of a higher prevalence of the disorder, improved awareness by clinicians or a combination of both. There are no defined mechanisms of pathogenesis or curative therapy presently available. Oxidative stress, overactivation of the hypothalamic-pituitary-adrenal axis and increased gut-blood-brain-barrier permeability might be involved. The scope of this article is to integrate these findings and present the opinion that non-allergic activation of gastrointestinal and brain mast cells could contribute to many of the pathologic findings and provide unique targets for ASD therapy. We make suggestions for new research directives and possible novel therapies from readily available molecules.

The Immunology of Gluten Sensitivity beyond the Intestinal Tract

Celiac disease and gluten-sensitive enteropathy are terms that have been used to refer to a disease process affecting the small bowel. However, evidence has been accumulated in literature demonstrating that gluten sensitivity or celiac disease can exist even in the absence of enteropathy, but affecting many organs. Based on overwhelming evidence, immunological pathogenesis has been demonstrated in the joint, the heart, thyroid, bone, and, in particular, the brain cerebellum and neuronal synapsin I. When blood samples of patients with celiac disease are tested against gliadin and different tissue antigens, in addition to gliadin antibody, a significant percentage of them exhibit elevation in antibodies against transglutaminase, heat shock protein, collagen, thyroid, myosin, endothelial cell, bone antigen (transglutaminase), myelin basic protein, cerebellar and synapsin. This elevation of autoantibodies in patients with celiac disease may result in neuroimmune disorders. In fact, in comparison to the general population, the incidence of various autoimmune disorders, including gluten ataxia, is increased up to 30-fold in patients with celiac disease. Therefore, immune evaluation of patients with gluten sensitivity or celiac disease, in addition to gliadin and transglutaminase, should include antibody measurement against thyroglobulin, thyroid peroxidase, heat shock protein, bone transglutaminase, myelin basic protein, cerebellar peptide and synapsin. This novel laboratory approach to gluten sensitivity and autoimmunity may enable clinicians to detect markers of autoimmune diseases. Early identification of gluten sensitive and celiac disease patients and implementation of a gluten-free diet may result in significant improvement and control of associated diseases.

The Immunology of Immediate and Delayed Hypersensitivity Reaction to Gluten

The immunology of gluten hypersensitivity and celiac disease has been pursued with significant interest in the past 20 years. For the prevention of systemic diseases, most pathogens that gain entry into our bodies must be met with an effective immune response, yet in the gastrointestinal tract it is equally important that commensal bacteria and a diverse collection of dietary proteins and peptides be recognized without eliciting an active immune response or constant activation of the inflammatory pathway. This phenomenon of hyporesponsiveness to food antigens is known as oral tolerance. This oral tolerance to dietary antigens is maintained by three different mechanisms: anergy, cell deletion and immune suppression. However, in the presence of mechanical/chemical stressors and infections, this tolerance may break down, and gut associated lymphoid tissues (GALT) will react to different luminal antigens. The reaction of GALT to these antigens may lead to the production of pro-inflammatory cytokines, opening of tight junctions, entry of undigested antigens into the circulation, and the subsequent production of IgA, IgG, IgM and IgE antibodies in blood and secretory components. Like any other food hypersensitivity reaction, gluten sensitivity can be divided into immediate and delayed hypersensitivities. In this review an attempt is made first to differentiate immediate hypersensitivity to gliadin, mediated by IgE, from delayed hypersensitivity, which is mediated by IgA and IgG. Furthermore, we attempt to differentiate between gluten hypersensitivity with enteropathy (celiac disease) and gluten hypersensitivity without enteropathy.

A case of celiac disease mimicking amyotrophic lateral sclerosis

BACKGROUND

A 44-year-old male presented to a general neurology clinic with a 6-month history of progressive right-sided spastic hemiparesis without sensory symptoms or signs. The thigh muscle in the affected leg showed signs of wasting. The patient had a remote family history of celiac disease.

INVESTIGATIONS

Neurological examination, neurophysiological studies, brain MRI scan, routine blood tests, duodenal biopsy, cerebrospinal fluid analysis including polymerase chain reaction test for JC virus DNA, serological testing for HIV and for the presence of serum antibodies to endomysium, gliadin and tissue transglutaminase.

DIAGNOSIS

Celiac disease with neurological involvement, mimicking amyotrophic lateral sclerosis.

MANAGEMENT

Strict gluten-free diet.

Gluten sensitivity in patients with primary Sjögren's syndrome

OBJECTIVE

To evaluate the rectal mucosal response to gluten as an indication of gluten sensitivity in patients with primary Sjögren's syndrome (pSS).

MATERIAL AND METHODS

Rectal challenges with wheat gluten were performed in 20 patients with pSS and 18 healthy control subjects. Fifteen hours after challenge the mucosal production of nitric oxide (NO) was measured.

RESULTS

Five patients with pSS had a significant increase in the luminal release of NO after the rectal gluten challenge, indicating gluten sensitivity. All were HLA-DQ2 and/or -DQ8-positive. Two of the patients with increased NO had antibodies against transglutaminase and a duodenal biopsy showed an absolutely flat mucosa consistent with coeliac disease in one of the patients. Before gluten challenge, 15 of the Sjögren's syndrome (SS) patients reported gastrointestinal symptoms, and 8 reported intolerance to various food products. No correlation was found between gluten sensitivity and self-reported food intolerance or gastrointestinal symptoms.

CONCLUSIONS

Rectal mucosal inflammatory response after gluten challenge is often seen in patients with pSS, signifying gluten sensitivity. However, this reactivity is not necessarily linked to coeliac disease.

Myopathy associated with gluten sensitivity

Ataxia and peripheral neuropathy are the most common neurological manifestations of gluten sensitivity. Myopathy is a less common and poorly characterized additional neurological manifestation of gluten sensitivity. We present our experience with 13 patients who presented with symptoms and signs suggestive of a myopathy and in whom investigation led to the diagnosis of gluten sensitivity. Three of these patients had a neuropathy with or without ataxia in addition to the myopathy. The mean age at onset of the myopathic symptoms was 54 years. Ten patients had neurophysiological evidence of myopathy. Inflammatory myopathy was the most common finding on neuropathological examination. One patient had basophilic rimmed vacuoles suggestive of inclusion-body myositis. Six patients received immunosuppressive treatment in addition to starting on a gluten-free diet; five improved and one remained unchanged. Among seven patients not on immunosuppressive treatment, four showed clinical improvement of the myopathy with a gluten-free diet. The improvement was also associated with reduction or normalization of serum creatine kinase level. The myopathy progressed in one patient who refused the gluten-free diet. Myopathy may be another manifestation of gluten sensitivity and is likely to have an immune-mediated pathogenesis. A gluten-free diet may be a useful therapeutic intervention.

In celiac disease, a subset of autoantibodies against transglutaminase binds toll-like receptor 4 and induces activation of monocytes

BACKGROUND

Celiac disease is a small intestine inflammatory disorder with multiple organ involvement, sustained by an inappropriate immune response to dietary gluten. Anti-transglutaminase antibodies are a typical serological marker in patients with active disease, and may disappear during a gluten-free diet treatment. Involvement of infectious agents and innate immunity has been suggested but never proven. Molecular mimicry is one of the mechanisms that links infection and autoimmunity.

METHODS AND FINDINGS

In our attempt to clarify the pathogenesis of celiac disease, we screened a random peptide library with pooled sera of patients affected by active disease after a pre-screening with the sera of the same patients on a gluten-free diet. We identified a peptide recognized by serum immunoglobulins of patients with active disease, but not by those of patients on a gluten-free diet. This peptide shares homology with the rotavirus major neutralizing protein VP-7 and with the self-antigens tissue transglutaminase, human heat shock protein 60, desmoglein 1, and Toll-like receptor 4. We show that antibodies against the peptide affinity-purified from the sera of patients with active disease recognize the viral product and self-antigens in ELISA and Western blot. These antibodies were able to induce increased epithelial cell permeability evaluated by transepithelial flux of [(3)H] mannitol in the T84 human intestinal epithelial cell line. Finally, the purified antibodies induced monocyte activation upon binding Toll-like receptor 4, evaluated both by surface expression of activation markers and by production of pro-inflammatory cytokines.

CONCLUSIONS

Our findings show that in active celiac disease, a subset of anti-transglutaminase IgA antibodies recognize the viral protein VP-7, suggesting a possible involvement of rotavirus infection in the pathogenesis of the disease, through a mechanism of molecular mimicry. Moreover, such antibodies recognize self-antigens and are functionally active, able to increase intestinal permeability and induce monocyte activation. We therefore provide evidence for the involvement of innate immunity in the pathogenesis of celiac disease through a previously unknown mechanism of engagement of Toll-like receptor 4.

Functional polymorphism of the NFKB1 gene promoter is not relevant in predisposition to celiac disease

OBJECTIVE

The nuclear factor (NF)-kappaB is one of the pivotal regulators of autoimmunity and inflammation, which has been shown to be activated in the inflamed mucosa of patients with celiac disease (CD). Recently, in the NFKB1 gene promoter region, a common insertion/deletion (-94ins/delATTG) polymorphism located between two putative key promoter regulatory elements was described. The aim of this study was to investigate the contribution of the -94ins/delATTG NFKB1 gene promoter functional variant to CD genetic predisposition.

MATERIAL AND METHODS

A case-control cohort comprising 478 patients with CD and 711 healthy controls as well as a panel of 196 celiac families was genotyped for the 94ins/delATTG NFKB1 polymorphism, using a polymerase chain reaction (PCR) method combined with fluorescence technology.

RESULTS

We found no statistically significant differences between CD patients and controls when the -94ins/delATTG genotype and allele distributions were compared. Accordingly, the familial analysis did not reach statistically significant deviation in the transmission of -94ins/delATTG alleles to the affected offspring.

CONCLUSIONS

From these results, it could be suggested that the -94ins/delATTG NFKB1 polymorphism does not play a major role in CD susceptibility.

Ataxie avec sensibilité au gluten, mythe ou réalité ?

INTRODUCTION

Gluten ataxia refers to the association of idiopathic ataxia despite exhaustive investigations with gluten sensitivity defined by anti-gliadin antibodies (AGA) presence in blood. This is a controversial concept.

PATIENTS AND METHODS

We screened 33 patients, who were hospitalized in 2003 and had subacute or chronic ataxia for presence of circulating AGA. Twelve patients were positive and their clinical and biological features were studied.

RESULTS

Among the twelve patients, we concluded that gluten ataxia was present in only eight, including one case of celiac disease. Among these eight patients, five had the usual features of gluten ataxia (progressive cerebellar ataxia affecting mainly lower limbs), but one patient presented unusual left cerebellar hemisyndrome and the two others displayed polyneuropathy with proprioceptive ataxia. Cerebellar atrophy was confirmed with magnetic resonance imaging in five cases and association with other antibodies was found in six cases. Among the four other patients positive for AGA, investigations revealed one case of multiple sclerosis, one case of late-onset Friedreich ataxia, one case of basilar tuberculous meningitis and one case of type 2 diabetes.

CONCLUSION

Screening for AGA presence should be systematically performed at presentation of patients with unknown etiology ataxia; in the event AGA are present without any other etiology, treatment with gluten-free diet must be discussed. However, the responsibility of AGA in the pathogenesis of neurological signs is highly debatable and further experimental work is required. Two pathophysiological hypotheses are suggested: (1) overexpression of cerebellar epitopes, in case of primary cerebellar pathology, leading to excessive immune response directed against these epitopes; and (2) molecular mimicry with cross-reactivity of antigens usually directed against gliadin, but also recognizing Purkinje cells epitopes.

Identification and analysis of multivalent proteolytically resistant peptides from gluten: implications for celiac sprue

Dietary gluten proteins from wheat, rye, and barley are the primary triggers for the immuno-pathogenesis of Celiac Sprue, a widespread immune disease of the small intestine. Recent molecular and structural analyses of representative gluten proteins, most notably alpha- and gamma-gliadin proteins from wheat, have improved our understanding of these pathogenic mechanisms. In particular, based on the properties of a 33-mer peptide, generated from alpha-gliadin under physiological conditions, a link between digestive resistance and inflammatory character of gluten has been proposed. Here, we report three lines of investigation in support of this hypothesis. First, biochemical and immunological analysis of deletion mutants of alpha-2 gliadin confirmed that the DQ2 restricted T cell response to the alpha-2 gliadin are directed toward the epitopes clustered within the 33-mer. Second, proteolytic analysis of a representative gamma-gliadin led to the identification of another multivalent 26-mer peptide that was also resistant to further gastric, pancreatic and intestinal brush border degradation, and was a good substrate of human transglutaminase 2 (TG2). Analogous to the 33-mer, the synthetic 26-mer peptide displayed markedly enhanced T cell antigenicity compared to monovalent control peptides. Finally, in silico analysis of the gluten proteome led to the identification of at least 60 putative peptides that share the common characteristics of the 33-mer and the 26-mer peptides. Together, these results highlight the pivotal role of physiologically generated, proteolytically stable, TG2-reactive, multivalent peptides in the immune response to dietary gluten in Celiac Sprue patients. Prolyl endopeptidase treatment was shown to abolish the antigenicity of both the 33-mer and the 26-mer peptides, and was also predicted to have comparable effects on other proline-rich putatively immunotoxic peptides identified from other polypeptides within the gluten proteome.