Nonceliac Wheat Sensitivity: An Immune-Mediated Condition with Systemic Manifestations

Nonallergic Diseases Associated With Foods

Clinicians are faced with evaluating real and alleged reactions to foods that may be allergic or nonallergic. Pathogenesis, diagnosis, and treatment of various non-IgE-mediated diseases are discussed in this review. These food-related conditions range from mild to severe. Referral for an allergy workup may be pursued despite the lack of IgE-mediated symptoms. Diagnostic testing is available for defined non-IgE-mediated food diseases that are either immunologic or nonimmunologic. These include celiac disease and related disorders, carbohydrate maldigestion, pancreatic insufficiency, and histamine intolerance. In contrast, there is a paucity of definitive studies to prove food intolerance diseases. There are no definitive diagnostic criteria or testing for nonceliac gluten sensitivity. Functional gastrointestinal disorders, such as irritable bowel syndrome, are better stratified diagnostically but still lack reliable testing. Both nonceliac gluten sensitivity and irritable bowel syndrome are linked to dietary triggers including fermentable oligosaccharides, disaccharides, monosaccharides, and polyols. Therefore, dietary alteration alone may be diagnostic and therapeutic when all other conditions are ruled out. These conditions are important considerations when evaluating a patient with history of a food reaction. There is little evidence that foods are causative in other ailments such as acne, migraines, and nasal congestion and hypersecretion.

Myths and Facts about Food Intolerance: A Narrative Review

Most adverse reactions to food are patient self-reported and not based on validated tests but nevertheless lead to dietary restrictions, with patients believing that these restrictions will improve their symptoms and quality of life. We aimed to clarify the myths and reality of common food intolerances, giving clinicians a guide on diagnosing and treating these cases. We performed a narrative review of the latest evidence on the widespread food intolerances reported by our patients, giving indications on the clinical presentations, possible tests, and dietary suggestions, and underlining the myths and reality. While lactose intolerance and hereditary fructose intolerance are based on well-defined mechanisms and have validated diagnostic tests, non-coeliac gluten sensitivity and fermentable oligosaccharide, disaccharide, monosaccharide, and polyol (FODMAP) intolerance are mainly based on patients' reports. Others, like non-hereditary fructose, sorbitol, and histamine intolerance, still need more evidence and often cause unnecessary dietary restrictions. Finally, the main outcome of the present review is that the medical community should work to reduce the spread of unvalidated tests, the leading cause of the problematic management of our patients.

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.

Reference proteomes of five wheat species as starting point for future design of cultivars with lower allergenic potential

Wheat is an important staple food and its processing quality is largely driven by proteins. However, there is a sizable number of people with inflammatory reactions to wheat proteins, namely celiac disease, wheat allergy and the syndrome of non-celiac wheat sensitivity. Thus, proteome profiles should be of high importance for stakeholders along the wheat supply chain. We applied liquid chromatography-tandem mass spectrometry-based proteomics to establish the flour reference proteome for five wheat species, ancient to modern, each based on 10 cultivars grown in three diverse environments. We identified at least 2540 proteins in each species and a cluster analyses clearly separated the species based on their proteome profiles. Even more, >50% of proteins significantly differed between species - many of them implicated in products' quality, grain-starch synthesis, plant stress regulation and proven or potential allergic reactions in humans. Notably, the expression of several important wheat proteins was found to be mainly driven by genetics vs. environmental factors, which enables selection and refinement of improved cultivars for the wheat supply chain as long as rapid test methods will be developed. Especially einkorn expressed 5.4 and 7.2-fold lower quantities of potential allergens and immunogenic amylase trypsin inhibitors, respectively, than common wheat, whereas potential allergen content was intermediate in tetraploid wheat species. This urgently warrants well-targeted clinical studies, where the developed reference proteomes will help to design representative test diets.

Construction of a Fab Library Merging Chains from Semisynthetic and Immune Origin, Suitable for Developing New Tools for Gluten Immunodetection in Food

The observed increase in the prevalence of gluten-related disorders has prompted the development of novel immunological systems for gluten detection in foodstuff. The innovation on these methods relies on the generation of new antibodies, which might alternatively be obtained by molecular evolution methods such as phage display. This work presents a novel approach for the generation of a Fab library by merging semi-synthetic heavy chains built-up from a pre-existent recombinant antibody fragment (dAb8E) with an immune light chain set derived from celiac donors. From the initial phage population (10⁷ candidates) and after three rounds of selection and amplification, four different clones were isolated for further characterization. The phage Fab8E-4 presented the best features to be applied in an indirect ELISA for the detection of gluten in foods, resulting in improved specificity and sensitivity.

Effectiveness of the low-FODMAP diet in improving non-celiac gluten sensitivity: a systematic review

Non-celiac gluten sensitivity is characterised by the presence of gastrointestinal and extraintestinal symptoms following gluten ingestion. Recent studies suggested an association between non-celiac gluten sensitivity and the consumption of fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAP). This systematic review aimed to examine literature evidence on the relationship between non-celiac gluten sensitivity and FODMAP intake. A comprehensive search was carried out for randomised clinical trials addressing gastrointestinal symptoms as the primary outcome, published between 2010 and 2020 in Portuguese, English or Spanish, and indexed in Scopus, PubMed, SciELO, Cochrane Library, CINAHL, Embase or VHL (LILACS) databases. The systematic review was performed using the population, intervention, comparison and outcome (PICO) framework. A total of 1133 articles were retrieved for further assessment. Three articles were selected for systematic review, one of which included two interventions with different periods and assessments. Quality of evidence was assessed according to the GRADE protocol. The selected articles used different instruments to measure gastrointestinal symptoms and quality of life, hindering comparison of data. Clinical trials identified an association between decreased gastrointestinal symptoms and FODMAP restriction. There are few studies on the topic, and those available used different instruments to assess gastrointestinal symptoms and quality of life. Nevertheless, current evidence supports the gluten-free diet still represents first-line therapy. However, a FODMAP restriction can decrease gastrointestinal symptoms in individuals with non-celiac gluten sensitivity. Further research is needed to confirm this finding.

Gut reactions: emerging mechanisms of abdominal pain from food intake

Abdominal pain, which is a form of visceral pain, is a highly prevalent symptom worldwide frequently occurring following food ingestion. Its pathophysiology is complex, and many factors, including intestinal environmental cues, the immune system, or the molecular composition of foods, can influence the development of postprandial abdominal pain. Because of the poor efficacy of drug treatments, current strategies are often limited to the exclusion of culprit food(s) from the diet. However, there are two important limitations to this approach. First, patients suffering from food-induced abdominal pain usually recognize several food items as the cause of their gastrointestinal symptoms. Second, not all offending foods can always be identified by these patients. Newly identified mechanisms involving neuroimmune interactions and their communication with the intestinal microbiota shed light on the development of new therapeutic strategies. In this Mini-Review, these novel mechanisms and relevance of such findings are highlighted.

Diploid Wheats: Are They Less Immunogenic for Non-Celiac Wheat Sensitive Consumers?

Non-celiac wheat sensitivity (NCWS) is a clinical entity induced by the ingestion of gluten that leads to intestinal and/or extraintestinal symptoms, and is diagnosed when celiac disease and wheat allergy have been ruled out. In addition to gluten, other grains’ components, including amylase trypsin inhibitors (ATIs) and fermentable short-chain carbohydrates (FODMAPs), may trigger symptoms in NCWS subjects. Several studies suggest that, compared with tetraploid and hexaploid modern wheats, ancient diploid wheats species could possess a lower immunogenicity for subjects suffering from NCWS. This review aims to discuss available evidence related to the immunological features of diploid wheats compared to common wheats, and at outlining new dietary opportunities for NCWS subjects.

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.

Nutrition in Patients with Lactose Malabsorption, Celiac Disease, and Related Disorders

Lactose malabsorption (LM), celiac disease (CD), non-celiac gluten sensitivity (NCGS), and irritable bowel syndrome (IBS) are conditions associated with food triggers, improvement after withdrawal, treatment with dietary restriction, and subsequent nutritional detriments. LM occurs when there is incomplete hydrolysis of lactose due to lactase deficiency and frequently produces abdominal symptoms; therefore, it can cause lactose intolerance (LI). A lactose-restricted diet is frequently recommended, although it can potentially lead to nutrient deficiencies. Furthermore, lactose is an essential component of fermentable oligo-, di-, and monosaccharides and polyols (FODMAPs) and is subsequently associated with intolerance to these compounds, especially in IBS. LM commonly presents in CD. Nutritional deficits are common in CD and can continue even on a gluten-free diet (GFD). Conditions triggered by gluten are known as gluten-related disorders (GRDs), including CD, wheat allergy, and NCGS. IBS can also be associated with a gluten sensitivity. A GFD is the treatment for CD, GRDs, and gluten sensitive IBS, although compliance with this restricted diet can be difficult. Strict dietary therapies can have a negative effect on quality of life. This review aims to provide an overview of the difficult nutritional elements of these disorders, which are critical for medical providers to recognize when managing these patients.

Associations Between Subclass Profile of IgG Response to Gluten and the Gastrointestinal and Motor Symptoms in Children With Cerebral Palsy

OBJECTIVE

Gastrointestinal problems are often seen in children with cerebral palsy, although the etiology and underlying mechanisms are not fully understood. Recent data point to significantly elevated levels of IgG antibody to dietary gluten in cerebral palsy independent of celiac disease, a gluten-mediated autoimmune enteropathy. We aimed to further characterize this antibody response by examining its subclass distribution and target reactivity in the context of relevant patient symptom profile.

METHODS

Study participants included children with cerebral palsy (n = 70) and celiac disease (n = 85), as well as unaffected controls (n = 30). Serum IgG antibody to gluten was investigated for subclass distribution, pattern of reactivity towards target proteins, and relationship with gastrointestinal symptoms and motor function.

RESULTS

The anti-gluten IgG antibody response in the cerebral palsy cohort was constituted of all 4 subclasses. In comparison with celiac disease, however, IgG1, IgG2, and IgG3 subclasses were significantly lower, whereas the IgG4 response was significantly higher in cerebral palsy. Within the cohort of cerebral palsy patients, levels of anti-gluten IgG1, IgG3, and IgG4 were greater in those with gastrointestinal symptoms, and the IgG3 subclass antibody correlated inversely with gross motor function. The anti-gluten IgG antibodies targeted a broad range of gliadin and glutenin proteins.

CONCLUSIONS

These findings reveal an anti-gluten IgG subclass distribution in cerebral palsy that is significantly different from that in celiac disease. Furthermore, the observed association between IgG subclass and symptom profile is suggestive of a relationship between the immune response and disease pathophysiology that may indicate a role for defects in gut immune and barrier function in cerebral palsy.

Non-Celiac Gluten Sensitivity: An Update

Non-celiac gluten sensitivity (NCGS) is a clinical entity characterized by the absence of celiac disease and wheat allergy in patients that trigger reproducible symptomatic responses to gluten-containing foods consumption. Due to the lack of sensitive and reproducible biomarkers for NCGS diagnosis, placebo-controlled gluten challenges must be carried out for its diagnosis. The gluten challenges can be either double- or single-blind, for research or clinical practice purposes, respectively. For improving our understanding about the magnitude and relevance of NCGS in different populations, epidemiological studies based on self-report have been carried out. However, the gluten challenge-based prevalence of NCGS remains to be estimated. Since NCGS was recently recognized as a clinical entity, more studies are needed to delve into NCGS pathogenesis, for instance, the molecular interactions between the suspected cereal grain components that trigger NCGS, such as fermentable oligo-, di-, monosaccharides, and polyols (FODMAPs) and amylase and trypsin inhibitors, and the immune system remains to be elucidated. Although still under debate, NCGS patients can be susceptible to only one or more than one of the NCGS triggers. The treatment of NCGS involves the dietary restriction of the suspected triggers of the disease, but there is controversial data about the effectiveness of different dietary interventions such as the gluten-free diet and low-FODMAP diet. Certainly, our understanding of NCGS is improving quickly due to the constant availability of new scientific information on this topic. Thus, the aim of the present narrative review is to present an up-to-date overview on NCGS from epidemiology to current therapy.

Food Allergy and Intolerance: A Narrative Review on Nutritional Concerns

Adverse food reactions include immune-mediated food allergies and non-immune-mediated intolerances. However, this distinction and the involvement of different pathogenetic mechanisms are often confused. Furthermore, there is a discrepancy between the perceived vs. actual prevalence of immune-mediated food allergies and non-immune reactions to food that are extremely common. The risk of an inappropriate approach to their correct identification can lead to inappropriate diets with severe nutritional deficiencies. This narrative review provides an outline of the pathophysiologic and clinical features of immune and non-immune adverse reactions to food-along with general diagnostic and therapeutic strategies. Special emphasis is placed on specific nutritional concerns for each of these conditions from the combined point of view of gastroenterology and immunology, in an attempt to offer a useful tool to practicing physicians in discriminating these diverging disease entities and planning their correct management. We conclude that a correct diagnostic approach and dietary control of both immune- and non-immune-mediated food-induced diseases might minimize the nutritional gaps in these patients, thus helping to improve their quality of life and reduce the economic costs of their management.

Non-Celiac Gluten/Wheat Sensitivity: Clinical Characteristics and Microbiota and Mycobiota Composition by Response to the Gluten Challenge Test

The aims of this observational “proof-of-concept” study were to analyze the clinical/psychological characteristics and gut microbiota/mycobiota composition of individuals with suspected non-celiac gluten/wheat sensitivity (NCGS/WS) according to responses to the double-blind-placebo-controlled (DBPC) crossover gluten challenge test. Fifty individuals with suspected NCGS/WS were subjected to the DBPC challenge test; anthropometric measurements, psychometric questionnaires, and fecal samples were collected. Twenty-seven (54%) participants were gluten responsive (NCGS), and 23 were placebo responsive, with an order effect. NCGS individuals displayed a significantly lower risk of eating disorders and a higher mental health score when compared to placebo-responsive participants, confirmed by multiple logistic regression analyses (OR = 0.87; 95% CI 0.76–0.98, p = 0.021, and OR = 1.30; 95% CI 1.06–1.59, p = 0.009, respectively). Principal coordinate analyses based on microbiota composition showed a separation by the DBPC response (p = 0.039). For Bacteroides (p = 0.05) and Parabacteroides (p = 0.007), the frequency of amplicon sequence variants was lower, and that for Blautia (p = 0.009) and Streptococcus (p = 0.004) was higher in NCGS individuals at multiple regression analyses. No difference in the mycobiota composition was detected between the groups. In conclusion, almost half of the individuals with suspected gluten sensitivity reported symptoms with placebo; they showed lower mental health scores, increased risk for eating disorders, and a different gut microbiota composition.

Non-celiac wheat sensitivity: rationality and irrationality of a gluten-free diet in individuals affected with non-celiac disease: a review

Non-celiac gluten or wheat sensitivity (NCWS) is a “clinical entity induced by the ingestion of wheat leading to intestinal and/or extraintestinal symptoms that improve once the wheat-containing foodstuff is removed from the diet, and celiac disease and wheat allergy have been excluded”. This mostly accepted definition raises several points that remain controversial on this condition. In the present review, the authors summarize the most recent advances in the clinic and research on NCWS through an accurate analysis of different studies. We screened PubMed, Medline, Embase, and Scopus using the keywords “non-celiac gluten sensitivity”, “non-celiac wheat sensitivity”, and “diagnosis”. We would like to emphasize two main points, including (A) the controversial clinical and etiological aspects in different trials and experiences with particular attention to the Salerno criteria for the diagnosis of NCWS and (B) the histological aspects. The etiology of NCWS remains controversial, and the relationship with irritable bowel syndrome is obscure. Histologically, the duodenal mucosa may show a variable pattern from unremarkable to a slight increase in the number of T lymphocytes in the superficial epithelium of villi. The endorsement of this disease is based on a positive response to a gluten-free diet for a limited period, followed by the reappearance of symptoms after gluten challenge. The Salerno expert criteria may help to diagnose NCWS accurately. Social media and inaccurate interpretation of websites may jeopardize the diagnostic process if individuals self-label as gluten intolerant.

Non-celiac gluten sensitivity as a rare cause of growth retardation in children: a case series study

AIM

Herein, we present five children and adolescents with a final diagnosis of non-celiac gluten sensitivity (NCGS).

BACKGROUND

Non-celiac gluten sensitivity (NCGS) is a condition characterized by gastrointestinal and extra-intestinal symptoms triggered by ingestion of gluten-containing compounds, e.g., wheat, rye, and barley, in subjects without celiac disease or wheat allergy.

METHODS

Demographic characteristics, clinical manifestations, serum biomarkers and skin prick test were evaluated. Patient data was also recorded after they followed a gluten-free diet (GFD). Height and weight were measured, and all patients were examined 6 months after following the suggested GFD.

RESULTS

All patients had failure to thrive and abdominal pain. Clinical symptoms were reduced, and significant weight and height gains were detected after 1 month of following a gluten-free diet.

CONCLUSION

The relationship between failure to thrive (FTT) and NCGS is still unknown; hence, NCGS may be one of the main causes of FTT which can be prevented by gluten-free diets.

From Polyclonal Sera to Recombinant Antibodies: A Review of Immunological Detection of Gluten in Foodstuff

Gluten is the ethanol-soluble protein fraction of cereal endosperms like wheat, rye, and barley. It is widely used in the food industry because of the physical-chemical properties it gives to dough. Nevertheless, there are some gluten-related diseases that are presenting increasing prevalences, e.g., celiac disease, for which a strict gluten-free diet is the best treatment. Due to this situation, gluten labeling legislation has been developed in several countries around the world. This article reviews the gluten immune detection systems that have been applied to comply with such regulations. These systems have followed the development of antibody biotechnology, which comprise three major methodologies: polyclonal antibodies, monoclonal antibodies (mAbs) derived from hybridoma cells (some examples are 401.21, R5, G12, and α-20 antibodies), and the most recent methodology of recombinant antibodies. Initially, the main objective was the consecution of new high-affinity antibodies, resulting in low detection and quantification limits that are mainly achieved with the R5 mAb (the gold standard for gluten detection). Increasing knowledge about the causes of gluten-related diseases has increased the complexity of research in this field, with current efforts not only focusing on the development of more specific and sensitive systems for gluten but also the detection of protein motifs related to pathogenicity. New tools based on recombinant antibodies will provide adequate safety and traceability methodologies to meet the increasing market demand for gluten-free products.

Is Gluten the Only Culprit for Non-Celiac Gluten/Wheat Sensitivity?

The gluten-free diet (GFD) has gained increasing popularity in recent years, supported by marketing campaigns, media messages and social networks. Nevertheless, real knowledge of gluten and GF-related implications for health is still poor among the general population. The GFD has also been suggested for non-celiac gluten/wheat sensitivity (NCG/WS), a clinical entity characterized by intestinal and extraintestinal symptoms induced by gluten ingestion in the absence of celiac disease (CD) or wheat allergy (WA). NCG/WS should be regarded as an "umbrella term" including a variety of different conditions where gluten is likely not the only factor responsible for triggering symptoms. Other compounds aside from gluten may be involved in the pathogenesis of NCG/WS. These include fructans, which are part of fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAPs), amylase trypsin inhibitors (ATIs), wheat germ agglutinin (WGA) and glyphosate. The GFD might be an appropriate dietary approach for patients with self-reported gluten/wheat-dependent symptoms. A low-FODMAP diet (LFD) should be the first dietary option for patients referring symptoms more related to FODMAPs than gluten/wheat and the second-line treatment for those with self-reported gluten/wheat-related symptoms not responding to the GFD. A personalized approach, regular follow-up and the help of a skilled dietician are mandatory.

The Two Faces of Wheat

Wheat-based foods have been staple foods since about 10,000 years and constitute a major source of energy, dietary fiber, and micronutrients for the world population. The role of wheat in our diet, however, has recently been scrutinized by pseudoscientific books and media reports promoting the overall impression that wheat consumption makes people sick, stupid, fat, and addicted. Consequently, numerous consumers in Western countries have started to question their dietary habits related to wheat consumption and voluntarily decided to adopt a wheat-free diet without a medical diagnosis of any wheat-related disorder (WRD), such as celiac disease, wheat allergy, or non-celiac gluten sensitivity. The aim of this review is to achieve an objective judgment of the positive aspects of wheat consumption as well as adverse effects for individuals suffering from WRDs. The first part presents wheat constituents and their positive nutritional value, in particular, the consumption of products from whole-grain flours. The second part is focused on WRDs that affect predisposed individuals and can be treated with a gluten-free or -reduced diet. Based on all available scientific knowledge, wheat consumption is safe and healthy for the vast majority of people. There is no scientific evidence to support that the general population would benefit from a wheat-free diet.

Minimal Lesions of the Small Intestinal Mucosa: More than Morphology

Minimal lesions of the small bowel are mucosal changes characterized by an increased number of intraepithelial lymphocytes (with or without crypt hyperplasia) and normal villous architecture. Such changes are associated with a wide spectrum of conditions, ranging from food intolerances to infections, and from drugs to immune diseases, with different clinical profiles and manifestations, which complicates the formulation of a differential diagnosis. Patient history, symptom evaluation, and histopathology are the diagnostic features needed to establish a correct diagnosis. Physicians should assist pathologists in formulating a precise morphological evaluation by taking well-oriented small intestinal biopsies and collecting informative clinical findings that inform histopathology. In this current clinical controversy, the authors provide the reader with an appraisal of the small intestine minimal lesions through a careful analysis of the major conditions (e.g., celiac disease and other non-celiac disorders) responsible for such changes and their differential diagnosis. Also, we acknowledge that some of the diseases detailed in this article may progress from an early minimal lesion to overt mucosal atrophy. Thus, the timing of the diagnosis is of paramount importance.

TNF-α, IL-17, and IL-22 production in the rectal mucosa of nonceliac wheat sensitivity patients: role of adaptive immunity

In recent years, a new gluten- or wheat-related disease has emerged, a condition labeled "nonceliac gluten sensitivity" (NCGS) or "nonceliac wheat sensitivity" (NCWS). NCWS pathogenesis is still uncertain and attributed to very different mechanisms. We aimed to study the different T-lymphocyte subsets in the rectal mucosa of NCWS patients to demonstrate the possible contribution of adaptative immune response. Twelve patients (11 women, 1 man, age range 23-61 yr, median 32 yr) with a definitive diagnosis of NCWS were recruited at random for the present study. They underwent rectal endoscopy with multiple mucosal biopsies at the end of a double-blind placebo-controlled (DBPC) wheat challenge when they reported the reappearance of the symptoms. As controls we included 11 "healthy patients", sex- and age-matched with the patients who underwent colonoscopy evaluation for rectal bleeding due to hemorrhoids. Cells freshly obtained from rectal tissue were stained to detect anti-CD45, anti-CD3, anti-CD4, and anti-CD8. Furthermore, intracellular staining was performed with anti-tumor necrosis factor (TNF)-α, anti-interleukin (IL)-17, and anti-IL-22. Production of TNF-α by CD45+, CD3+, CD4+, and CD8+ cells, as well as of IL-17 by CD4+ cells, was higher in the rectal tissue of NCWS patients than in controls. On the contrary, IL-22 production by CD8+ cells was lower in NCWS patients than in the controls. In NCWS patients diagnosed by DBPC wheat challenge, there is a complex immunological activation, with a significant role for the adaptive response.NEW & NOTEWORTHY Nonceliac wheat sensitivity (NCWS) is a syndrome characterized by symptoms triggered by gluten intake. The pathogenesis is still uncertain. Studies have shown a role for innate immunity. We demonstrated that production of TNF-α by CD45+, CD3+, CD4+, and CD8+ cells and of IL-17 by CD4+ cells is higher in the rectal tissue of NCWS patients than in controls. We clearly demonstrated that in patients with NCWS there is a significant role for the adaptive response.

Noncoeliac wheat sensitivity and diet

PURPOSE OF REVIEW

Noncoeliac gluten sensitivity (NCGS) can be suspected after exclusion of coeliac disease and wheat allergy. However, poorly understood pathogenesis of the NCGS, lack of gold standard for diagnosis and agreement in the definition for the NCGS condition, open the space for future investigation. This review aims to give an overview on the diagnosis and effective diet composition in the treatment of NCGS symptoms.

RECENT FINDINGS

It appears that a diet low in fermentable oligo, di, and monosaccharides and polyols (FODMAPs) and gluten-free diet play a prominent role in the strategy of NCGS management. Considering available evidence with respect to diagnostic tools, it is challenging to prepare a standard guideline for NCGS diagnosis and treatment with clear cut-offs for symptom reduction/improvement that could directly be translated into test results. Nutritional support, including the use of pre/probiotics, has to be tailored to the individual situation of NCGS patients.

SUMMARY

The exclusion of such components of wheat as amylase/trypsin inhibitors, wheat-germ agglutinins, or free of FODMAPs diet can reduce clinical symptoms of NCGS. The further investigation on microbiota changes may strengthen the knowledge in this area, where the major challenge is to develop biomarkers for NCGS investigation.

Celiac disease serology and gut microbiome following proton pump inhibitor treatment

BACKGROUND

Celiac disease is an autoimmune enteropathy characterized by an aberrant immune response to ingested gluten in genetically predisposed individuals. Studies have pointed to a rising prevalence of celiac disease in recent decades. Changes in diet and use of medication that may impact the gut microbiome have been suggested as potential contributors. Exposure to proton pump inhibitors (PPIs) was recently found to be associated with an increased risk for subsequent diagnosis of celiac disease. We aimed to investigate potential mechanisms for this link by examining the relationship between PPI use and gluten-related immune responses in the context of changes in gut microbiome.

METHODS

We performed a post hoc analysis of blood and fecal samples from a recent randomized trial in order to assess the potential association between PPI use and development of celiac disease serology in conjunction with alterations in gastrointestinal microbial composition. The study included 12 healthy participants who were administered a PPI (Omeprazole; 40 mg twice daily) for 4 or 8 weeks.

RESULTS

The analysis did not reveal an overall significant change in levels of serologic markers of celiac disease for the study cohort in response to PPI treatment. However, one individual developed a marked increase in the celiac disease-specific autoantibody response to transglutaminase 2 in conjunction with enhanced immune reactivity to gluten during the trial. Genotyping revealed positivity for the celiac disease-associated HLA-DQ2 and -DQ8 alleles. Furthermore, the observed elevation in antibody responses was closely associated with a sharp increase in fecal abundance of bacteria of the order Actinomycetales.

CONCLUSIONS

The results of this exploratory analysis support further investigation of molecular mechanisms involved in the contribution of PPIs to celiac disease risk through the potential enhancement of gluten immunopathology and changes in gut microbial population.

Effect of Gluten-Free Diet on Gut Microbiota Composition in Patients with Celiac Disease and Non-Celiac Gluten/Wheat Sensitivity

Celiac disease (CD) and non-celiac gluten/wheat sensitivity (NCG/WS) are the two most frequent conditions belonging to gluten-related disorders (GRDs). Both these diseases are triggered and worsened by gluten proteins ingestion, although other components, such as amylase/trypsin inhibitors (ATI) and fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAPs), seem to be involved in the NCG/WS onset. Therefore, the only effective treatment to date is the long-life adherence to a strictly gluten-free diet. Recently, increasing attention has been paid to the intestinal barrier, a dynamic system comprising various components, which regulate the delicate crosstalk between metabolic, motor, neuroendocrine and immunological functions. Among the elements characterizing the intestinal barrier, the microbiota plays a key role, modulating the gut integrity maintenance, the immune response and the inflammation process, linked to the CD and NCG/WS outbreak. This narrative review addresses the most recent findings on the gut microbiota modulation induced by the gluten-free diet (GFD) in healthy, CD and NCG/WS patients.

Mast cell-nerve interactions correlate with bloating and abdominal pain severity in patients with non-celiac gluten / wheat sensitivity

BACKGROUND

Gastrointestinal (GI) and extra-GI symptoms/manifestations represent key clinical features of patients with non-celiac gluten/wheat sensitivity (NCG/WS). This study aimed to investigate neuro-immune (focusing on mast cells, MCs) interactions in the duodenal submucosa of patients with NCG/WS.

METHODS

Submucosal whole mounts from duodenal biopsies of 34 patients with self-reported NCG/WS, 28 with celiac disease (CD), 13 with functional dyspepsia (FD), and 24 healthy controls (HC) were analyzed by immunohistochemistry. Quantitative data on neuronal and MCs density and the percentage of MCs in close vicinity to nerves were obtained, and correlations among neurons, MC density and MC-nerve distance (D), and symptoms were assessed in the three groups.

KEY RESULTS

The number of submucosal neurons was not different among groups. In NCG/WS, MC density was not different from HC, while it was slightly increased vs. CD (P = .07) and significantly decreased vs. FD (P < .05). The percentage of MCs close to nerves (D < 15 µm) was similarly increased in all three pathological groups vs. HC (P < .001). In NCG/WS, MC infiltration correlated with bloating (P = .001) and abdominal pain severity (P = .03) and the percentage of MCs in proximity to neurons correlated with the number of GI symptoms (D < 5 µm; P = .05), bloating and abdominal pain severity (D < 15um; P = .01).

CONCLUSIONS AND INFERENCES

Submucosal MC infiltration and the close (within 15 µm) MC-to-nerve proximity in the duodenum of NCG/WS patients are features providing a histopathological basis to better understand GI symptoms in this condition.

Gluten Vehicle and Placebo for Non-Celiac Gluten Sensitivity Assessment

Non-celiac gluten sensitivity (NCGS) is a syndrome characterized by gastrointestinal and extraintestinal manifestations triggered after gluten ingestion in the absence of celiac disease and wheat allergy. Because of the lack of biomarkers for NCGS diagnosis, the cornerstone for its assessment is a single- or double-blind placebo-controlled (DBPC) gluten challenge. However, there are some non-standardized points in the diagnostic approach proposed by the experts. This complicate comparisons among the results published by different research groups. The gluten vehicle and placebo must be indistinguishable from each other, which entails sensory and technological evaluations of the designed gluten vehicle and placebo products. At the moment, there is no standardized method for the preparation of the gluten vehicle and placebo for carrying out DBPC gluten challenges for NCGS assessment. This review focuses on the challenges that researchers have to face, either for the development of an accepted gluten vehicle and placebo or for identifying NCGS cases on the basis of DBPC gluten challenges.

Navigating the Gluten-Free Boom: The Dark Side of Gluten Free Diet

In gluten dependent conditions the gluten free diet is the cornerstone of therapy, decreasing disease activity, improving health and quality of life and treating or preventing the associated complications. Gluten withdrawal implies strict and lifelong elimination not only of wheat, barley, rye, and wheat-contaminated oats, but also of numerous non-nutritional products where components of wheat are often added. Due to multiple reasons the diet is difficult to follow and the long-term adherence is decreased with time. The present review summarizes the dark side of gluten restriction where nutritional deficiencies, toxicity, morbidity, mortality, and mental health problems are reported. The aim being to increase awareness, avoid, detect and treat the side effects and to promote a healthier nutrition, for the patient's benefits.