Psoriasis and Risk of Celiac Disease: A Systematic Review and Meta-analysis

Associations between Celiac Disease, Extra-Gastrointestinal Manifestations, and Gluten-Free Diet: A Narrative Overview

Millions of children and adults worldwide suffer from undiagnosed and untreated celiac disease (CeD). The clinical picture of CeD is highly heterogeneous and comprises manifestations that can affect almost the whole body. This narrative overview is aimed at characterizing diseases and complaints that are associated with unrecognized CeD and that frequently involve sites other than the gastrointestinal (G.I.) tract, i.e., dental, otorhinolaryngological, and ocular complications; skin and hair abnormalities; afflictions of the bones, joints, and muscles; cardiovascular affectations; kidney diseases; neuro-psychiatric disorders; and gynecological-obstetrical manifestations. The association between CeD and extra-GI manifestations is frequently overlooked, which leads to a delay in diagnosis. Most CeD-mediated disorders can be treated with a strict gluten-free diet (GFD), but some of them are irreversible unless CeD is diagnosed in time. Some manifestations can be classified as risk factors for CeD, and CeD screening tests for affected patients should be selectively considered. Apart from gastroenterologists, specialists in other medical disciplines can play an important role in identifying people with unrecognized CeD and may help prevent its progress and long-term complications. Further comprehensive investigations are necessary to clarify the pathogenesis of extra-GI manifestations and the effect of a GFD.

Psoriasis, bone and bowel: a comprehensive review and new insights

Psoriasis is a chronic immune-mediated disorder affecting about 2% of the population worldwide which is associated with significant morbidity. The disease usually presents as raised, well-demarcated erythematous plaques with adherent silvery scales. Psoriasis can appear at any age but it has two peaks occurring at 15–20 and 55–60 years of age. It affects males and females equally. Despite the multitude of investigations about psoriasis and even development of drugs with satisfactory results, its pathogenesis is not fully understood yet and its course is unpredictable. Various environmental triggers, e.g., obesity, stress and drugs may induce disease in genetically susceptible patients. Although psoriasis was considered primarily as a disease of the skin, more investigations have been revealed its systemic nature. Psoriatic arthritis (PsA) may complicate up to one-third of cases of psoriasis vulgaris (PV). Also, the association between psoriasis and a variety of other immune-mediated disorders such as inflammatory bowel disease (IBD) and celiac disease (CD) has been confirmed in various studies. Moreover, a growing body of evidences indicates that psoriasis shares some common histological and phenotypical properties with the spectrum of osteoimmunological diseases such as Paget’s disease of bone (PDB). Thus, exploring the common molecular and genetic mechanisms underlying psoriasis and related disorders is of paramount importance for better elucidating disease pathogenesis and designing more targeted treatments.

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.

Metabolic Disorders and Psoriasis: Exploring the Role of Nutritional Interventions

(1) Background: Psoriasis is a chronic autoimmune disease with a close relationship with metabolic diseases such as obesity, diabetes, and dyslipidemia. The aim of this review was to identify the relationship between psoriasis, metabolic diseases, and dietetic therapies. According to recent findings, there is a strong association between psoriasis and obesity as well as vitamin D and micronutrient deficiencies. (2) Methods: This review was conducted via PubMed, aiming to search for studies involving psoriasis linked with metabolic disorders or with nutritional treatments. (3) Results: Our review shows that a healthy lifestyle can positively influence the course of the disease. The maintaining of a proper body weight together with physical activity and good nutritional choices are associated with an improvement in psoriasis severity. A Mediterranean diet rich in fiber, vitamins, and polyphenols may indeed be a strategy for controlling psoriasis symptoms. The effectiveness of this diet lies not only in its anti-inflammatory power, but also in its ability to favorably influence the intestinal microbiota and counteract dysbiosis, which is a risk factor for many autoimmune diseases. (4) Conclusions: In synergy with standard therapy, the adoption of an appropriate diet can be recommended to improve the clinical expression of psoriasis and reduce the incidence of comorbidities.

Skin gluten-related disorders: new and old cutaneous manifestations to be considered

The term gluten-related disorders (GRD) refer to a spectrum of different clinical manifestations triggered by the ingestion of gluten in genetically susceptible individuals, including coeliac disease (CD), wheat allergy and non-celiac gluten sensitivity (NCGS). GRD are characterized by a large variety of clinical presentations with both intestinal and extra-intestinal manifestations. The latter may affect almost every organ of the body, including the skin. Besides the well-known association between CD and dermatitis herpetiformis, considered as the cutaneous specific manifestation of CD, many other muco-cutaneous disorders have been associated to GRD. In this review, we analyzed the main features of dermatological diseases with a proven association with GRD and those that improve after a gluten-free diet, focusing on the newly described cutaneous manifestations associated with NCGS. Our main hypothesis is that a "cutaneous-gluten sensitivity," as specific cutaneous manifestation of NCGS, may exist and could represent a diagnostic marker of NCGS.

Screening of antigliadin and antitissue transglutaminase antibodies in patients with chronic plaque psoriasis: a case-control study

BACKGROUND

In this study, we aimed to investigate different types of celiac antibodies in psoriasis patients and to see if the presenceof the antibodies was associated with other variables.

METHODS

We included patients with plaque psoriasis who were followed up in our dermatology clinic between February 2019 and February 2021 and added a healthy control group for comparison. The antibodies studied were serum antitissue transglutaminase (tTG)-IgA, tTG-IgG, antigliadin antibody (AGA)-IgA, and AGA-IgG. The patients' records were used to note age, sex, the pattern of psoriasis involvement, psoriasis area and severity index (PASI), presence of hypertension, presence of type 2 diabetes mellitus, use of methotrexate, and use of biologic agents.

RESULTS

Sixty-five psoriasis patients (31 F, 34 M, mean age: 38.9 ± 15.2) and 65 controls (42 F, 23 M, mean age: 40.7 ± 13.2) wereincluded in the study. There was no significant difference in antibody levels between the groups: tTG-IgA (2.4 U/mL vs 3.2 U/mL, p = 0.11), tTG-IgG (2.2 U/mL vs 3.2 U/mL, p = 0.74), AGA-IgA (2.4 U/mL vs 3.5 U/mL, p = 0.068), and AGA-IgG (3.2 U/mL vs 4.2 U/mL, p = 0.15). One patient from the psoriasis group only had borderline positive antibody levels whereas the rest of the psoriasis and control group had negative levels. Hypertensive psoriasis patients had significantly higher AGA-IgA titers compared to normotensive psoriasis patients (4.2 U/mL vs 2.3 U/mL, p = 0.005).

DISCUSSION

There was no increase in the AGA-IgA/IgG and tTG-IgA/IgG levels in psoriasis patients compared to the healthy population. However, hypertensive psoriasis patients had higher AGA-IgA levels compared to normotensive ones.

A Comprehensive Review of the Neurological Manifestations of Celiac Disease and Its Treatment

Celiac disease (CD) is a common chronic inflammatory disorder occurring in genetically predisposed individuals secondary to gluten ingestion. CD usually presents with gastrointestinal symptoms such as pain, bloating, flatulence, and constipation or diarrhea. However, individuals can present in a nonclassical manner with only extraintestinal symptoms. The neurological manifestations of CD include ataxia, cognitive impairment, epilepsy, headache, and neuropathy. A lifelong gluten-free diet is the current recommended treatment for CD. This review discusses the relevant neurological manifestations associated with CD and the novel therapeutics. Further research is required to get a better understanding of the underlying pathophysiology of the neurological manifestations associated with CD. Clinicians should keep CD in the differential diagnosis in individuals presenting with neurological dysfunction of unknown cause.

Gut Microbiota in Psoriasis

Psoriasis is a chronic inflammatory skin disease with autoimmune pathogenic characteristics and is caused by chronic inflammation, which results in uncontrolled keratinocyte growth and defective differentiation. The link between the gut microbiota and immune system regulation opened a novel angle to understand the pathogenesis of many chronic multifactorial diseases, including psoriasis. Current evidence suggests that modulation of the gut microbiota, both through dietary approaches and through supplementation with probiotics and prebiotics, could represent a novel therapeutic approach. The present work aims to highlight the latest scientific evidence regarding the microbiome alterations of psoriatic patients, as well as state of the art insights in terms of microbiome-targeted therapies as promising preventive and therapeutic tools for psoriasis.

Nutritional Therapy in Persons Suffering from Psoriasis

Psoriasis is a chronic inflammatory skin disease. Immunological, genetic, and environmental factors, including diet, play a part in the pathogenesis of psoriasis. Metabolic syndrome or its components are frequent co-morbidities in persons with psoriasis. A change of eating habits can improve the quality of life of patients by relieving skin lesions and by reducing the risk of other diseases. A low-energy diet is recommended for patients with excess body weight. Persons suffering from psoriasis should limit the intake of saturated fatty acids and replace them with polyunsaturated fatty acids from the omega-3 family, which have an anti-inflammatory effect. In diet therapy for persons with psoriasis, the introduction of antioxidants such as vitamin A, vitamin C, vitamin E, carotenoids, flavonoids, and selenium is extremely important. Vitamin D supplementation is also recommended. Some authors suggest that alternative diets have a positive effect on the course of psoriasis. These diets include: a gluten-free diet, a vegetarian diet, and a Mediterranean diet. Diet therapy for patients with psoriasis should also be tailored to pharmacological treatment. For instance, folic acid supplementation is introduced in persons taking methotrexate. The purpose of this paper is to discuss in detail the nutritional recommendations for persons with psoriasis.

Nutrition and psoriasis

Nutrition and dietary supplements are commonly used in the management of psoriasis; however, evidence of their efficacy is inconsistent. Although some dietary interventions have been shown to improve psoriasis consistently, others have little evidence supporting their use. We review common dietary interventions for the management of psoriasis and the evidence behind them. Caloric restriction, especially in overweight and obese individuals, has been shown to consistently diminish psoriatic activity. Evidence about other supplements and dietary interventions is inconsistent. Given the cost and side effects of pharmaceutical treatments for psoriasis, larger, long-term studies on the use of nutrition for the management of psoriasis are necessary.

Skin Manifestations and Coeliac Disease in Paediatric Population

Celiac disease (CD) is an immune-mediated enteropathy caused by gluten ingestion, affecting approximately 1% of the worldwide population. Extraintestinal symptoms may be present as the first signs of CD, years before the CD diagnosis is made. A great variety of extraintestinal manifestations may be associated with CD. Cutaneous manifestations represent the main extraintestinal manifestations, with dermatitis herpetiformis being the most common in patients with CD. In adults, it has been demonstrated that the role of a gluten-free diet is crucial not only for the recovery of signs and symptoms associated with CD but also for cutaneous manifestations, which often improve after gluten avoidance. In children with CD, the association with skin disorders is well documented regarding dermatitis herpetiformis, but studies considering other dermatological conditions, such as psoriasis and atopic dermatitis, are few. The prevalence and manifestations of dermatological disorders in celiac children are often different from those in adults, explaining the gap between these populations. In addition, the therapeutic role of a gluten-free diet in the improvement in skin alterations is not fully understood in children and in adult population except for dermatitis herpetiformis. Therefore, cutaneous CD symptoms need to be known and recognized by physicians despite their specialties to improve early CD diagnosis, which is critical for a better prognosis. This review describes the current scientific evidence on skin manifestations associated with CD in the pediatric population.

Unconventional treatment options in psoriasis: A review

Psoriasis is a common skin disease that affects 1-3% of the general population. The treatment depends on body surface area involved, quality of life impairment and associated comorbidities. The treatment options include topical therapy, phototherapy, conventional systemic therapy (methotrexate, cyclosporine and acitretin), biologics and oral small molecules (apremilast and tofacitinib). Despite the availability of newer therapies such as biologics and oral small molecules, many a time, there is a paucity of treatment options due to the chronic nature of the disease, end-organ toxicity of the conventional drugs or high cost of newer drugs. In these scenarios, unconventional treatment options may be utilized as stand-alone or adjuvant therapy. In this review, we have discussed these uncommonly used treatment options in the management of psoriasis.

Discovering the Context of People With Disabilities: Semantic Categorization Test and Environmental Factors Mapping of Word Embeddings from Reddit

BACKGROUND

The World Health Organization's International Classification of Functioning Disability and Health (ICF) conceptualizes disability not solely as a problem that resides in the individual, but as a health experience that occurs in a context. Word embeddings build on the idea that words that occur in similar contexts tend to have similar meanings. In spite of both sharing "context" as a key component, word embeddings have been scarcely applied in disability. In this work, we propose social media (particularly, Reddit) to link them.

OBJECTIVE

The objective of our study is to train a model for generating word associations using a small dataset (a subreddit on disability) able to retrieve meaningful content. This content will be formally validated and applied to the discovery of related terms in the corpus of the disability subreddit that represent the physical, social, and attitudinal environment (as defined by a formal framework like the ICF) of people with disabilities.

METHODS

Reddit data were collected from pushshift.io with the pushshiftr R package as a wrapper. A word2vec model was trained with the wordVectors R package using the disability subreddit comments, and a preliminary validation was performed using a subset of Mikolov analogies. We used Van Overschelde's updated and expanded version of the Battig and Montague norms to perform a semantic categories test. Silhouette coefficients were calculated using cosine distance from the wordVectors R package. For each of the 5 ICF environmental factors (EF), we selected representative subcategories addressing different aspects of daily living (ADLs); then, for each subcategory, we identified specific terms extracted from their formal ICF definition and ran the word2vec model to generate their nearest semantic terms, validating the obtained nearest semantic terms using public evidence. Finally, we applied the model to a specific subcategory of an EF involved in a relevant use case in the field of rehabilitation.

RESULTS

We analyzed 96,314 comments posted between February 2009 and December 2019, by 10,411 Redditors. We trained word2vec and identified more than 30 analogies (eg, breakfast - 8 am + 8 pm = dinner). The semantic categorization test showed promising results over 60 categories; for example, s(A relative)=0.562, s(A sport)=0.475 provided remarkable explanations for low s values. We mapped the representative subcategories of all EF chapters and obtained the closest terms for each, which we confirmed with publications. This allowed immediate access (≤ 2 seconds) to the terms related to ADLs, ranging from apps "to know accessibility before you go" to adapted sports (boccia). For example, for the support and relationships EF subcategory, the closest term discovered by our model was "resilience," recently regarded as a key feature of rehabilitation, not yet having one unified definition. Our model discovered 10 closest terms, which we validated with publications, contributing to the "resilience" definition.

CONCLUSIONS

This study opens up interesting opportunities for the exploration and discovery of the use of a word2vec model that has been trained with a small disability dataset, leading to immediate, accurate, and often unknown (for authors, in many cases) terms related to ADLs within the ICF framework.

Gluten and skin disease beyond dermatitis herpetiformis: a review

Gluten, a protein found in wheat, rye, and barley, is known to cause an immune reaction in patients with celiac disease (CD) resulting in small bowel villous atrophy and impaired nutrient absorption and cutaneous manifestations in patients with dermatitis herpetiformis (DH). It is common that patients associate skin conditions with their diet, and the advantages of a gluten-free diet (GFD) are brought up frequently. Indeed, there is evidence that certain dermatologic conditions can respond to a GFD, especially for those with concomitant CD and DH. In the last decade, new data have become available on the significance of gluten in skin disease. Herein, we review the role of gluten and a GFD on various cutaneous diseases beyond DH.

Cognitive Deficit and White Matter Changes in Persons With Celiac Disease: A Population-Based Study

BACKGROUND & AIMS

There is debate over the presence and prevalence of brain injury in patients with celiac disease. To validate previous reports, we investigated the prevalence of neuropsychological dysfunction in persons with celiac disease included in the National UK Biobank, which contains experimental medical data from 500,000 adults in the United Kingdom.

METHODS

Biobank participants with celiac disease (n = 104; mean age, 63 years; 65% female) were matched with healthy individuals (controls, n = 198; mean age, 63 years; 67% female) for age, sex, level of education, body mass index, and diagnosis of hypertension. All participants were otherwise healthy. We compared scores from 5 cognitive tests and multiple choice responses to 6 questions about mental health between groups using the t test and chi-squared analyses. Groupwise analyses of magnetic resonance imaging brain data included a study of diffusion tensor imaging metrics (mean diffusivity, fractional anisotropy, radial diffusivity, axial diffusivity), voxel-based morphometry, and Mann-Whitney U comparisons of Fazekas grades.

RESULTS

Compared with control individuals, participants with celiac disease had significant deficits in reaction time (P = .004), and significantly higher proportions had indications of anxiety (P = .025), depression (P = .015), thoughts of self-harm (P = .025), and health-related unhappiness (P = .010). Tract-based spatial statistics analysis showed significantly increased axial diffusivity in widespread locations, demonstrating white matter changes in the brains of participants with celiac disease. Voxel-based morphometry and Fazekas grade analyses did not differ significantly between groups.

CONCLUSIONS

In an analysis of data from the UK Biobank, we found participants with celiac disease to have cognitive deficit, indications of worsened mental health, and white matter changes, based on analyses of brain images. These findings support the concept that celiac disease is associated with neurologic and psychological features.

The association of anti-gliadin and anti-transglutaminase antibodies and chronic plaque psoriasis in Indian patients: Preliminary results of a descriptive cross-sectional study

BACKGROUND

Gluten sensitivity among psoriasis patients and its association with gender, age, disease duration and severity of psoriasis are under studied in Indians.

OBJECTIVE

To examine association among serum levels of anti-tTG and anti-gliadin antibodies and clinical features including gender, age, duration and severity of psoriasis.

METHODS

Serum levels of anti-transglutaminase and anti-gliadin antibodies were measured quantitatively in 80 (M:F 57:23) psoriasis patients aged 15 to 83 years and matched healthy subjects.

RESULTS

Forty-five (56.3%) patients were aged ≥41years, duration of disease was >5years in 43(53.8%) patients, and 22 (27.5%) patients had moderate-to-severe psoriasis. Two (2.5%) patients had arthritis and elevated serum anti-gliadin antibody. Significantly more patients than controls had elevated serum anti-gliadin antibody (67.5% vs. 2.5%) and anti-transglutaminase antibody levels (62.5% vs. 0%). Two patients, each with mild and moderate-to-severe psoriasis, had highly elevated serum anti-gliadin antibody and symptoms akin to coeliac disease. Except for a longer duration of psoriasis in patients with elevated anti-gliadin antibodies, there was no statistically significant difference in gender, age, and severity of psoriasis when compared with patients having normal levels.

CONCLUSION

Significant elevation of serum anti-transglutaminase and anti-gliadin antibodies levels is noted in psoriasis patients reflecting a possible link. However, results need careful interpretation for any significance of gluten sensitivity in pathogenesis of psoriasis/arthritis or as a stand-alone risk factor for chronicity/severity of psoriasis or whether gluten-free diet will be ameliorating. Small number of subjects, cross-sectional study design, lack of pathological/endoscopic diagnosis and follow-up are study limitations.

Prevalence of coexisting autoimmune thyroidal diseases in coeliac disease is decreasing

BACKGROUND

Coeliac disease (CD) is associated with an increased risk of other immune-mediated conditions. Aim: To investigate the prevalence of coexistent immune-mediated diseases in CD patients, and changes in the prevalence of autoimmune thyroidal diseases over the last 50 years.

METHODS

Medical record data were collected retrospectively from 749 CD patients in Ireland. Prevalence of autoimmune diseases was compared with previously published results from general populations. Patients were divided into four groups based on the year of diagnosis to analyse changes in the prevalence of autoimmune thyroidal disease over time.

RESULTS

Median age at the time of CD diagnosis was 56 years (range 18-91 years). A total of 233 (31.1%) patients had a coexistent immune-mediated condition (IMC). Autoimmune thyroidal diseases were seen in 149 (19.9%) patients, hypothyroidism in 110 (14.7%), type 1 diabetes in 27 (3.6%), psoriasis in 20 (2.7%), inflammatory bowel disease in 14 (1.9%) and rheumatoid arthritis in 12 (1.6%). All conditions were more common in CD patients than in the general population. Type 1 diabetes was diagnosed mainly before CD, whereas there was no such trend in other conditions. Autoimmune thyroidal diseases became less common in female CD patients over time.

CONCLUSIONS

Prevalence of autoimmune diseases is increased in adult CD patients compared with the general population. However, concomitant autoimmune thyroidal diseases became less common over time in women.

Celiac Disease: Extraintestinal Manifestations and Associated Conditions

Celiac disease is a common form of enteropathy with frequent extraintestinal manifestations (EIM). Misrecognition of these presentations may lead to significant delays in diagnosis. Any organ may be involved, either through an immune/inflammatory phenomenon, or nutritional deficiencies. Some EIM, such as gluten ataxia, may be irreversible if left untreated, but most will improve with a gluten-free diet. Knowledge of the various EIM, as well as the associated conditions which do not improve on a gluten-free diet, will avoid delays in the diagnosis and management of celiac disease and associated manifestations.

Association between psoriasis and celiac disease: A systematic review and meta-analysis

BACKGROUND

Multiple studies have examined the association between psoriasis and celiac disease (CD). However, these studies have shown conflicting results.

OBJECTIVE

To analyze the association between psoriasis and CD.

METHODS

We conducted a systematic review of the case-control, cross-sectional, and cohort studies examining the association between psoriasis and CD in the PubMed, Scopus, and Cochrane databases. The adjusted effect sizes or crude data were extracted for quantitative analysis.

RESULTS

Of 754 citations initially identified, 18 studies were included. Random effects meta-analysis found significant odds ratios of 2.16 (95% confidence interval, 1.74-2.69; 9 studies) for CD in patients with psoriasis and 1.8 (95% confidence interval, 1.36-2.38; 8 studies) for psoriasis in patients with CD. We also found a significantly increased risk of new-onset psoriasis in CD (hazard ratio, 1.75; 95% confidence interval, 1.58-1.93). Subgroup analyses according to disease severity and geographic region could not be performed due to limited data.

CONCLUSION

This 2-way meta-analysis found a significant association between psoriasis and CD. Clinicians should be aware of this association. Patients with psoriasis with bowel complaints might benefit from screening for CD through questionnaires or interviews with subsequent gastroenterology consultation.

Celiac disease and risk of sarcoidosis: A systematic review and meta-analysis

BACKGROUND/OBJECTIVES

Several epidemiologic studies have suggested that patients with celiac disease may be at an increased risk of sarcoidosis but the results were inconsistent. This systematic review and meta-analysis was conducted with the aim to better characterize this risk by summarizing all available data.

METHODS

A literature review was performed using MEDLINE and EMBASE database from inception to February 2019. Studies that compared the risk of sarcoidosis among patients with celiac disease versus individuals without celiac disease were included. Pooled odds ratio (OR) and 95% confidence interval (CI) were calculated using a random-effect, generic inverse variance method.

RESULTS

Of 426 retrieved studies, four studies with 693 639 participants met the eligibility criteria and were included in meta-analysis. The risk of sarcoidosis among patients with celiac disease was higher than individuals without celiac disease with the pooled OR of 7.16 (95% CI, 1.48-34.56). The statistical heterogeneity of this study was high (I²  = 95%).

CONCLUSIONS

This systematic review and meta-analysis found a significantly higher risk of sarcoidosis among patients with celiac disease.

Dermatitis Herpetiformis: Novel Perspectives

Dermatitis herpetiformis (DH) is an inflammatory disease of the skin, considered the specific cutaneous manifestation of celiac disease (CD). Both DH and CD occur in gluten-sensitive individuals, share the same Human Leukocyte Antigen (HLA) haplotypes (DQ2 and DQ8), and improve following the administration of a gluten-free diet. Moreover, almost all DH patients show typical CD alterations at the small bowel biopsy, ranging from villous atrophy to augmented presence of intraepithelial lymphocytes, as well as the generation of circulating autoantibodies against tissue transglutaminase (tTG). Clinically, DH presents with polymorphic lesions, including papules, vesicles, and small blisters, symmetrically distributed in typical anatomical sites including the extensor aspects of the limbs, the elbows, the sacral regions, and the buttocks. Intense pruritus is almost the rule. However, many atypical presentations of DH have also been reported. Moreover, recent evidence suggested that DH is changing. Firstly, some studies reported a reduced incidence of DH, probably due to early recognition of CD, so that there is not enough time for DH to develop. Moreover, data from Japanese literature highlighted the absence of intestinal involvement as well as of the typical serological markers of CD (i.e., anti-tTG antibodies) in Japanese patients with DH. Similar cases may also occur in Caucasian patients, complicating DH diagnosis. The latter relies on the combination of clinical, histopathologic, and immunopathologic findings. Detecting granular IgA deposits at the dermal-epidermal junction by direct immunofluorescence (DIF) from perilesional skin represents the most specific diagnostic tool. Further, assessing serum titers of autoantibodies against epidermal transglutaminase (eTG), the supposed autoantigen of DH, may also serve as a clue for the diagnosis. However, a study from our group has recently demonstrated that granular IgA deposits may also occur in celiac patients with non-DH inflammatory skin diseases, raising questions about the effective role of eTG IgA autoantibodies in DH and suggesting the need of revising diagnostic criteria, conceivably emphasizing clinical aspects of the disease along with DIF. DH usually responds to the gluten-free diet. Topical clobetasol ointment or dapsone may be also applied to favor rapid disease control. Our review will focus on novel pathogenic insights, controversies, and management aspects of DH.

An update on the cutaneous manifestations of coeliac disease and non-coeliac gluten sensitivity

INTRODUCTION

Coeliac disease is a gluten-induced immune-mediated enteropathy, characterised by the expression of specific genotypes and the production of autoantibodies. The inflammatory process specifically targets the intestinal mucosa, but gastrointestinal and extraintestinal signs and symptoms can also be present. Non-coeliac gluten sensitivity (NCGS) can be diagnosed in individuals who have intestinal and/or extraintestinal symptoms related to the ingestion of gluten, but do not have autoantibodies and do not suffer from lesions in the duodenal mucosa. Among the extraintestinal manifestations, cutaneous manifestations are the most common for both diseases.

PURPOSE

We conducted this review to illustrate the common and uncommon features underlying the association of coeliac disease and NCGS with cutaneous manifestations related to gluten ingestion. Areas covered: The roles of innate and adaptive immunity in the cutaneous appearance of gluten sensitivity will be discussed.

Clinical guidelines on the diagnosis and treatment of celiac disease in Mexico

Celiac disease, celiac sprue, or gluten-sensitive enteropathy, is a generalized autoimmune disease characterized by chronic inflammation and atrophy of the small bowel mucosa. It is caused by dietary exposure to gluten and affects genetically predisposed individuals. In Mexico, at least 800,000 are estimated to possibly have the disease, prompting the Asociación Mexicana de Gastroenterología to summon a multidisciplinary group of experts to develop the "Clinical guidelines on the diagnosis and treatment of celiac disease in Mexico" and establish recommendations for the medical community, its patients, and the general population. The participating medical professionals were divided into three working groups and were given the selected bibliographic material by the coordinators (ART, LUD, JMRT), who proposed the statements that were discussed and voted upon in three sessions: two voting rounds were carried out electronically and one at a face-to-face meeting. Thirty-nine statements were accepted, and once approved, were developed and revised by the coordinators, and their final version was approved by all the participants. It was emphasized in the document that epidemiology and risk factors associated with celiac disease (first-degree relatives, autoimmune diseases, high-risk populations) in Mexico are similar to those described in other parts of the world. Standards for diagnosing the disease and its appropriate treatment in the Mexican patient were established. The guidelines also highlighted the fact that a strict gluten-free diet is essential only in persons with confirmed celiac disease, and that the role of gluten is still a subject of debate in relation to nonceliac, gluten-sensitive patients.

Cutaneous and Mucosal Manifestations Associated with Celiac Disease

Celiac disease (CD) is an immune-mediated, gluten-induced enteropathy that affects predisposed individuals of all ages. Many patients with CD do not report gastrointestinal symptoms making it difficult to reach an early diagnosis. On the other hand, CD is related to a wide spectrum of extra-intestinal manifestations, with dermatitis herpetiformis (DH) being the best characterized. These associated conditions may be the clue to reaching the diagnosis of CD. Over the last few years, there have been multiple reports of the association between CD and several cutaneous manifestations that may improve with a gluten-free diet (GFD). The presence of some of these skin diseases, even in the absence of gastrointestinal symptoms, should give rise to an appropriate screening method for CD. The aim of this paper is to describe the different cutaneous manifestations that have been associated with CD and the possible mechanisms involved.

Association between celiac disease and schizophrenia: a meta-analysis

BACKGROUND/OBJECTIVE

Recent epidemiologic studies have suggested that patients with celiac disease might be at an increased risk of schizophrenia. However, the data on this risk remain inconclusive. This meta-analysis was conducted with the aim to summarize all available evidence.

METHODS

A literature search was carried out using MEDLINE and Embase database from inception to June 2017. Studies that compared the risk of schizophrenia among patients with celiac disease versus individuals without celiac disease were included. Pooled odds ratio and 95% confidence interval were calculated using a random-effect, generic inverse-variance method.

RESULTS

Of the 284 retrieved studies, four met our eligibility criteria and were included in the analysis. We found a higher risk of schizophrenia among patients with celiac disease compared with individuals without celiac disease with the pooled odds ratio of 2.03 (95% confidence interval: 1.45-2.86). The statistical heterogeneity of this study was insignificant (I=0%).

CONCLUSION

This systematic review and meta-analysis found a significantly higher risk of schizophrenia among patients with celiac disease.

HLA-Cw6 and psoriasis

Psoriasis is a multifactorial disease with a strong genetic background. HLA-Cw6 is one of the most strongly associated psoriasis susceptibility alleles. It is repeatedly observed to affect disease course, phenotypic features, severity, comorbidities and treatment outcomes. To the best of our knowledge, the roles of HLA-Cw6 in psoriasis have not yet been thoroughly reviewed. The worldwide frequency of the HLA-Cw6 allele varies greatly, with it being generally higher in white people than in Asians. The allele is associated with type I early-onset psoriasis. Stress, obesity and streptococcal pharyngitis are commonly observed in HLA-Cw6-positive patients. Phenotypically, HLA-Cw6 has been found to be associated with guttate psoriasis. In addition, patients carrying the allele are more likely to have arm, leg and trunk involvement, and the Koebner phenomenon. Patients with psoriatic arthritis with HLA-Cw6 more often have early onset and tend to show cutaneous symptoms before musculoskeletal symptoms. HLA-Cw6-positive patients have been shown in several studies to be more responsive to methotrexate and ustekinumab. However, this difference in ustekinumab efficacy was only moderate in a post-hoc analysis of a pivotal phase III study. HLA-Cw6 positivity also tends to be less frequent in high-need patients who fail conventional therapy. Small studies have also investigated the role of HLA-Cw6 in remission of psoriasis during pregnancy, and with the comorbidities of photosensitivity and atherosclerosis. Given the diverse nature of psoriasis pathogenesis, as well as the difference of HLA-Cw6 positivity in different ethnic groups, more studies are needed to confirm the role of HLA-Cw6 in psoriasis.

The role of the gut microbiome in systemic inflammatory disease

The role of the gut microbiome in models of inflammatory and autoimmune disease is now well characterized. Renewed interest in the human microbiome and its metabolites, as well as notable advances in host mucosal immunology, has opened multiple avenues of research to potentially modulate inflammatory responses. The complexity and interdependence of these diet-microbe-metabolite-host interactions are rapidly being unraveled. Importantly, most of the progress in the field comes from new knowledge about the functional properties of these microorganisms in physiology and their effect in mucosal immunity and distal inflammation. This review summarizes the preclinical and clinical evidence on how dietary, probiotic, prebiotic, and microbiome based therapeutics affect our understanding of wellness and disease, particularly in autoimmunity.