Clinical response to gluten withdrawal is not an indicator of coeliac disease

Yield of Gluten Challenge in Patients on Self-Prescribed Gluten-Free Diets

BACKGROUND

Patients on a gluten-free diet (GFD) whose celiac disease (CD) status is unknown may undergo gluten challenge (GC) to clarify their diagnosis. Though this is an established diagnostic practice, the proportion of patients undergoing GC who are diagnosed with CD is unknown.

AIMS

We aimed to analyze which factors were predictive of having CD in a cohort of patients who underwent GC followed by upper endoscopy with duodenal biopsy.

METHODS

We identified adult patients at a CD referral center who had been on a GFD and then underwent GC to determine a diagnosis of CD during the years spanning 2006 to 2020. We compared those patients found to have CD (defined as villus atrophy/Marsh 3) on duodenal biopsy with those who did not, using the chi square and Fischer exact tests.

RESULTS

We identified 206 patients who underwent GC. Of these 206, 30 (14%) were diagnosed with CD based on post-GC duodenal biopsy. 176 of the 206 (85%) patients reported various gastrointestinal symptoms, including bloating (39%), though these were more common in those without CD (any GI symptoms: 89% vs 67%, p 0.004; bloating: 43% vs 20%, p 0.019). Serology values, when normalized, including pre- and post-challenge TTG IgA (37% vs 1.7%, p 0.001; 23% versus 2.3%, p 0.001), DGP IgG and IgA (57% vs 2.8%, p 0.001; 37% vs 6.2%, p 0.001) were higher in the group of patients with CD.

CONCLUSION

Among patients undergoing GC for diagnostic purposes, only 14% had evidence of villus atrophy corresponding with CD on duodenal biopsy. The presence of any elevated pre-challenge serology was associated with CD. Bloating in combination with low serologies may help risk stratify patients as being less likely to have CD upon GC.

Gluten-related Disorders From Bench to Bedside

Celiac disease, non-celiac gluten sensitivity, and wheat allergy comprise 3 of the main conditions with wheat- and gluten-containing foods as the symptom trigger. Distinguishing between these entities can be daunting. In this review, we compare and contrast celiac disease, non-celiac gluten sensitivity, and wheat allergy to allow clinicians to determine which diagnosis fits their patient to facilitate high-quality management and longitudinal care.

Food Allergies and Intolerances: A Clinical Approach to the Diagnosis and Management of Adverse Reactions to Food

Food allergy is an aberrant immunological response to food antigen, which can result in potentially life-threatening reactions. It is often challenging to differentiate food allergy from other adverse reactions to food because their presentations can be indistinguishable. The purpose of this article is to give an overview of the classification, evaluation, and management of adverse food reactions, key differentiating features of food allergy, roles and limitations of various food allergy testing, and promising areas of emerging research. Case studies are used to highlight some of the clinical pearls in diagnosing and managing food-related diseases.

Pitfalls in the Diagnosis of Coeliac Disease and Gluten-Related Disorders

The spectrum of gluten-related disorders (GRD) has emerged as a relevant phenomenon possibly impacting on health care procedures and costs worldwide. Current classification of GRD is mainly based on their pathophysiology, and the following categories can be distinguished: immune-mediated disorders that include coeliac disease (CD), dermatitis herpetiformis (DH), and gluten ataxia (GA); allergic reactions such as wheat allergy (WA); and non-coeliac gluten sensitivity (NCGS), a condition characterized by both gastrointestinal and extra-intestinal symptoms subjectively believed to be induced by the ingestion of gluten/wheat that has recently gained popularity. Although CD, DH, and WA are well-defined clinical entities, whose diagnosis is based on specific diagnostic criteria, a diagnosis of NCGS may on the contrary be considered only after the exclusion of other organic disorders. Neither allergic nor autoimmune mechanisms have been found to be involved in NCGS. Mistakes in the diagnosis of GRD are still a relevant clinical problem that may result in overtreatment of patients being unnecessary started on a gluten-free diet and waste of health-care resources. On the basis of our clinical experience and literature, we aim to identify the main pitfalls in the diagnosis of CD and its complications, DH, and WA. We provide a practical methodological approach to guide clinicians on how to recognize and avoid them.

Possible role of intestinal stem cells in the pathophysiology of irritable bowel syndrome

The pathophysiology of irritable bowel syndrome (IBS) is not completely understood. However, several factors are known to play a role in pathophysiology of IBS such as genetics, diet, gut microbiota, gut endocrine cells, stress and low-grade inflammation. Understanding the pathophysiology of IBS may open the way for new treatment approaches. Low density of intestinal stem cells and low differentiation toward enteroendocrine cells has been reported recently in patients with IBS. These abnormalities are believed to be the cause of the low density of enteroendocrine cells seen in patients with IBS. Enteroendocrine cells regulate gastrointestinal motility, secretion, absorption and visceral sensitivity. Gastrointestinal dysmotility, abnormal absorption/secretion and visceral hypersensitivity are all seen in patients with IBS and haven been attributed to the low density the intestinal enteroendocrine cells in these patients. The present review conducted a literature search in Medline (PubMed) covering the last ten years until November 2019, where articles in English were included. Articles about the intestinal stem cells and their possible role in the pathophysiology of IBS are discussed in the present review. The present review discusses the assumption that intestinal stem cells play a central role in the pathophysiology of IBS and that the other factors known to contribute to the pathophysiology of IBS such as genetics, diet gut microbiota, stress, and low-grade inflammation exert their effects through affecting the intestinal stem cells. It reports further the data that support this assumption on genetics, diet, gut microbiota, stress with depletion of glutamine, and inflammation.

Gamma delta+ intraepithelial lymphocytes and coeliac lymphogram in a diagnostic approach to coeliac disease in patients with seronegative villous atrophy

BACKGROUND

The causes of seronegative villous atrophy can be grouped as coeliac or noncoeliac related. There is no consensus on how to approach subjects with seronegative coeliac disease.

AIM

To evaluate the accuracy of both an increase in CD3⁺ T-cell receptor gamma delta⁺ (TCRγδ⁺ ) intraepithelial lymphocytes and coeliac lymphogram for the diagnosis of coeliac disease in patients with seronegative villous atrophy.

METHODS

Sixty-seven consecutive patients with seronegative villous atrophy were included. Duodenal biopsies to assess TCRγδ⁺ and CD3^- by flow cytometry were performed at the index endoscopy. Coeliac lymphogram was defined as an increase in TCRγδ⁺ plus a decrease in CD3^- intraepithelial lymphocytes. Sensitivity, specificity and Fagan's nomogram were calculated.

RESULTS

Coeliac disease was diagnosed in 37 patients and noncoeliac villous atrophy in 30. Coeliac patients were younger (39 ± 3 vs 55 ± 3 years; P = 0.001), more often showed HLA-DQ2/8 (97.6% vs 61%; P = 0.002) and had a more severe histology (61% vs 32% Marsh 3b-c; P = 0.055), as compared to noncoeliac ones. Coeliac lymphogram was associated with a sensitivity of 87% (CI, 73.7-95) and specificity of 96.7% (82.7-99.9), whereas evaluating only TCRγδ⁺ yielded a sensitivity of 91.3% (79.2-97.6) and specificity of 83.3% (65.3-94.3). Among patients with a pre-test coeliac disease probability of 30%, post-test probabilities were 92% and 5% for positive and negative coeliac lymphogram, and 70% and 4% for positive and negative TCRγδ⁺ .

CONCLUSIONS

Coeliac lymphogram was associated with a high level of diagnostic evidence either against or in favour of coeliac disease in patients with seronegative villous atrophy.

Celiac Disease

Gluten-related disorders, including celiac disease, wheat allergy, and nonceliac gluten sensitivity (NCGS), are increasingly reported worldwide. Celiac disease is caused by an immune-mediated reaction to ingested gluten in genetically susceptible persons. NCGS is largely a diagnosis of exclusion when other causes of symptoms have been ruled out. All patients with celiac disease should be referred to a registered dietitian nutritionist with expertise in celiac disease and a gastroenterologist who specializes in celiac disease and malabsorptive disorders, and they should remain on a strict gluten-free diet indefinitely. This article provides an overview of gluten- and wheat-related disorders.

Overview in the clinical management of patients with seronegative villous atrophy

Differential diagnosis and management of enteropathies found in the context of seronegative villous atrophy (VA) are still a clinical challenge. Although seronegative coeliac disease may be the most frequent cause of serology-negative VA, other conditions must be taken into account in the differential diagnosis of seronegative VA. The rarity of these enteropathies with frequent overlapping of histological features may result in misclassification of such patients as affected by a seronegative or a refractory form of coeliac disease with consequent inappropriate treatments and long-term morbidity. The aim of this review is to summarize the current knowledge and to provide an evidence base and practical algorithmic approach for the investigation and management of seronegative VA.

Gluten-free diet in non-celiac patients: beliefs, truths, advantages and disadvantages

A gluten-free diet is the safest treatment for the treatment of patient with celiac disease (CD) and other gluten-related disorders. However, in the last years, gluten-free diet is one of the most popular diet followed by the general population and by patients affected from others clinical conditions, such as non-celiac gluten sensitivity (NCGS), irritable bowel syndrome (IBS), autism, neurological, psychiatric and rheumatologic diseases and for improving sports practice. This review highlights some questions about the appropriateness of following this trend answering to some questions such as how safe are the current gluten-free products, what are the benefits and side effects of gluten-free diet and what are clinical conditions that might benefit from gluten avoidance.

Evaluation of T cells in blood after a short gluten challenge for coeliac disease diagnosis

BACKGROUND AND AIM

To diagnose coeliac disease (CD) in individuals on a gluten free diet (GFD), we aimed to assess the utility of detecting activated γδ and CD8 T cells expressing gut-homing receptors after a short gluten challenge.

METHODS

We studied 15 CD patients and 35 non-CD controls, all exposed to three days of gluten when following a GFD. Peripheral blood was collected before and six days after starting gluten consumption, and the expression of CD103, β7 and CD38 in γδ and CD8 T cells was assessed by flow cytometry. Determination of IFN-γ and IP-10 was performed by means of ELISPOT and/or Luminex technology.

RESULTS

We observed both γδ and CD8 T cells coexpressing CD103, β7^hi and CD38 in every patient with CD on day six, but only in one control. The studied CD8 T subpopulation was easier to detect than the γδ subpopulation. Increased IFN-γ and IP-10 levels after challenge were observed in patients with CD, but not in controls.

CONCLUSION

A short three-day gluten challenge elicits the activation of CD103⁺ β7^hi CD8⁺ T cells in CD. These cells can be detected by flow cytometry in peripheral blood, opening new possibilities for CD diagnosis in individuals on a GFD.

Small bowel villous atrophy: celiac disease and beyond

Small bowel villous atrophy can represent a diagnostic challenge for gastroenterologists and pathologists. In Western countries small bowel atrophy and mild non-atrophic alterations are frequently caused by celiac disease. However, other pathology can mimic celiac disease microscopically, widening the differential diagnosis. The several novelties on this topic and the introduction of the device-assisted enteroscopy in the diagnostic flowchart make an update of the literature necessary. Areas covered: In this review, a description of the different clinical scenarios when facing with small bowel mucosal damage, particularly small bowel atrophy, is described. The published literature on this subject has been summarized and reviewed. Expert commentary: When an intestinal mucosal alteration is histologically demonstrated, the pathology report forms part of a more complex workup including serological data, clinical presentation and clinical history. A multidisciplinary team, including pathologists and enteroscopy-devoted endoscopists, is frequently required to manage patients with small bowel alterations, especially in cases of severe malabsorption syndrome.

Gluten ataxia is better classified as non-celiac gluten sensitivity than as celiac disease: a comparative clinical study

Gluten ataxia (GA) has customarily been considered to be the main neurological manifestation of celiac disease (CD). In recent years, the condition of non-celiac gluten sensitivity (NCGS) has been defined, which includes some patients who are not considered "true celiacs." We performed a comparative clinicopathological study of these three entities. We studied 31 GA, 48 CD and 37 NCGS patients, prospectively in the same center for a period of 7 years. The protocol study included two serological determinations for gluten sensitivity [anti-gliadin IgA and IgG (AGA) and anti-tissue transglutaminase IgA (TG) antibodies], HLA-DQ2 typing, and duodenal histological assessment. Demographics and investigative findings were compared. Females were 55 % in GA, 75 % in CD (p < 0.001), and 47 % in NCGS (N.S.). GA patients were older (59 ± 14 years) than CD (43 ± 13 years) and NCGS (41 ± 8 years) groups (p < 0.001). AGA positivity was higher in GA (100 %) than in CD (48 %) groups (p < 0.001), but similar to NCGS patients (89 %; N.S.); TG positivity was lower in GA (3.2 %) than in CD (33.3 %; p < 0.001), but similar to NCGS (2.7 %; N.S.). DQ2 (+) was lower in GA (32.2 %) than in CD (89.6 %; p < 0.001), but similar to NCGS (29.7 %; N.S.). Lymphocytic enteritis (Marsh type 1) was lower in GA (9.6 %) than in CD (66.7 %; p < 0.001), but similar to NCGS (10.8 %; N.S.). The other gluten sensitivity-related characteristics measured were different to CD patients, but very close to NCGS. We conclude that GA patients are better classified within the NCGS group, than within CD.

Prior Misdiagnosis of Celiac Disease Is Common Among Patients Referred to a Tertiary Care Center: A Prospective Cohort Study

OBJECTIVES

Interest of patients and physicians in celiac disease is growing worldwide, but without a corresponding increase in the awareness of the disease. Many patients are diagnosed as celiacs even without completing the whole diagnostic process, with consequent risk of misdiagnosis and delay in the evaluation of other diseases. The objective of this study was to assess the rates of prior celiac disease misdiagnosis among patients referred to a tertiary care center.

METHODS

From June 2013 to December 2014, we prospectively recruited patients referred for the first time to our Celiac Disease Center. Patients with a previous diagnosis of celiac disease underwent a diagnostic revaluation by second reading of duodenal tissue slides, dosage of specific antibodies, and/or duodenal biopsy sampling; HLA status was investigated in pertinent cases.

RESULTS

A total of 198 subjects were recruited. Of these, 91 "naïve" patients (46%) started the diagnostic screening for celiac disease; 58 of them (64-29% of the whole sample) were diagnosed as celiacs. The remaining 107 patients (54%) came with a previous diagnosis of celiac disease: of these, 52 (49-26% of the whole sample) presented with confirmed diagnosis of celiac disease, whereas 55 (51-28% of the whole sample) underwent diagnostic revaluation. After the reassessment, diagnosis was rejected in 43 cases (78-22% of the whole sample) and confirmed in the remaining 12 (22-6% of the whole sample). Overall, diagnosis was confirmed in only 64 of the 107 subjects with a previous diagnosis (60-32% of the whole sample). Diagnosis of celiac disease was more frequently confirmed in "naïve" patients compared those with a questionable previous diagnosis (64% vs. 22%; P<0.0001).

CONCLUSIONS

A considerable number of patients referred to a tertiary care center are inaccurately diagnosed with celiac disease. Although we cannot exclude that uncertain diagnosis was a reason for the referral, we suggest greater adherence to guidelines to minimize the burden of celiac disease misdiagnosis.

The relation between celiac disease, nonceliac gluten sensitivity and irritable bowel syndrome

Wheat products make a substantial contribution to the dietary intake of many people worldwide. Despite the many beneficial aspects of consuming wheat products, it is also responsible for several diseases such as celiac disease (CD), wheat allergy, and nonceliac gluten sensitivity (NCGS). CD and irritable bowel syndrome (IBS) patients have similar gastrointestinal symptoms, which can result in CD patients being misdiagnosed as having IBS. Therefore, CD should be excluded in IBS patients. A considerable proportion of CD patients suffer from IBS symptoms despite adherence to a gluten-free diet (GFD). The inflammation caused by gluten intake may not completely subside in some CD patients. It is not clear that gluten triggers the symptoms in NCGS, but there is compelling evidence that carbohydrates (fructans and galactans) in wheat does. It is likely that NCGS patients are a group of self-diagnosed IBS patients who self-treat by adhering to a GFD.

The spectrum of noncoeliac gluten sensitivity

The past 5 years have seen an increase in the use of a gluten-free diet outside a diagnosis of coeliac disease or IgE-mediated wheat allergy. This trend has led to the identification of a new clinical entity termed noncoeliac gluten sensitivity (NCGS). In this Review, we discuss the evidence for NCGS as demonstrated by the results of double-blind, placebo-controlled dietary rechallenge studies. Furthermore, the characteristic phenotype of individuals with NCGS is described as well as the symptom manifestations commonly reported after gluten exposure, which include intestinal symptoms consistent with IBS, and extraintestinal symptoms such as neurological dysfunction, psychological disturbances, fibromyalgia and skin rash. Moreover, emerging evidence suggests that NCGS can be associated with organic gastrointestinal pathologies, such as IBD, in which its presence might be a reflection of severe or stricturing disease. However, NCGS is not without its controversies and uncertainties, in particular pertaining to whether it is gluten or nongluten components of the grain evoking symptoms; evidence suggests that fermentable carbohydrates, amylase trypsin inhibitors and wheat-germ agglutinin can also be responsible culprits. Finally, we discuss the novel techniques that might help diagnose NCGS in the future.

Recent developments in the pathophysiology of irritable bowel syndrome

Irritable bowel syndrome (IBS) is a common gastrointestinal disorder, the pathophysiology of which is not completely known, although it has been shown that genetic/social learning factors, diet, intestinal microbiota, intestinal low-grade inflammation, and abnormal gastrointestinal endocrine cells play a major role. Studies of familial aggregation and on twins have confirmed the heritability of IBS. However, the proposed IBS risk genes are thus far nonvalidated hits rather than true predisposing factors. There is no convincing evidence that IBS patients suffer from food allergy/intolerance, with the effect exerted by diet seemingly caused by intake of poorly absorbed carbohydrates and fiber. Obesity is a possible comorbidity of IBS. Differences in the microbiota between IBS patients and healthy controls have been reported, but the association between IBS symptoms and specific bacterial species is uncertain. Low-grade inflammation appears to play a role in the pathophysiology of a major subset of IBS, namely postinfectious IBS. The density of intestinal endocrine cells is reduced in patients with IBS, possibly as a result of genetic factors, diet, intestinal microbiota, and low-grade inflammation interfering with the regulatory signals controlling the intestinal stem-cell clonogenic and differentiation activities. Furthermore, there is speculation that this decreased number of endocrine cells is responsible for the visceral hypersensitivity, disturbed gastrointestinal motility, and abnormal gut secretion seen in IBS patients.

Nonceliac gluten sensitivity

During the past decade there has been an impressive increase in popularity of the gluten-free diet (GFD)-now the most trendy alimentary habit in the United States and other countries. According to recent surveys, as many as 100 million Americans will consume gluten-free products within a year. Operating under the concept that the GFD benefits only individuals with celiac disease, health care professionals have struggled to separate the wheat from the chaff; there are claims that eliminating gluten from the diet increases health and helps with weight loss, or even that gluten can be harmful to every human being. However, apart from unfounded trends, a disorder related to ingestion of gluten or gluten-containing cereals, namely nonceliac gluten sensitivity (NCGS), has resurfaced in the literature, fueling a debate on the appropriateness of the GFD for people without celiac disease. Although there is clearly a fad component to the popularity of the GFD, there is also undisputable and increasing evidence for NCGS. However, we require a better understanding of the clinical presentation of NCGS, as well as its pathogenesis, epidemiology, management, and role in conditions such as irritable bowel syndrome, chronic fatigue, and autoimmunity. Before we can begin to identify and manage NCGS, there must be agreement on the nomenclature and definition of the disorder based on proper peer-reviewed scientific information. We review the most recent findings on NCGS and outline directions to dissipate some of the confusion related to this disorder.

Diet in irritable bowel syndrome

Irritable bowel syndrome (IBS) is a common chronic gastrointestinal disorder that is characterized by intermittent abdominal pain/discomfort, altered bowel habits and abdominal bloating/distension. This review aimed at presenting the recent developments concerning the role of diet in the pathophysiology and management of IBS. There is no convincing evidence that IBS patients suffer from food allergy/intolerance, and there is no evidence that gluten causes the debated new diagnosis of non-coeliac gluten sensitivity (NCGS). The component in wheat that triggers symptoms in NCGS appears to be the carbohydrates. Patients with NCGS appear to be IBS patients who are self-diagnosed and self-treated with a gluten-free diet. IBS symptoms are triggered by the consumption of the poorly absorbed fermentable oligo-, di-, monosaccharides and polyols (FODMAPs) and insoluble fibre. On reaching the distal small intestine and colon, FODMAPS and insoluble fibre increase the osmotic pressure in the large-intestine lumen and provide a substrate for bacterial fermentation, with consequent gas production, abdominal distension and abdominal pain or discomfort. Poor FODMAPS and insoluble fibres diet reduces the symptom and improve the quality of life in IBS patients. Moreover, it changes favourably the intestinal microbiota and restores the abnormalities in the gastrointestinal endocrine cells. Five gastrointestinal endocrine cell types that produce hormones regulating appetite and food intake are abnormal in IBS patients. Based on these hormonal abnormalities, one would expect that IBS patients to have increased food intake and body weight gain. However, the link between obesity and IBS is not fully studied. Individual dietary guidance for intake of poor FODMAPs and insoluble fibres diet in combination with probiotics intake and regular exercise is to be recommended for IBS patients.

Coeliac disease and noncoeliac gluten sensitivity

The spectrum of gluten-related disorders was restricted to coeliac disease and wheat allergy, but the new contemporary entity referred to as noncoeliac gluten sensitivity has gained recognition mainly in adults but also in children. Noncoeliac gluten sensitivity is defined as the presence of a variety of symptoms related to gluten ingestion in patients in whom coeliac disease and wheat allergy have been excluded. The pathophysiology and biomarkers of coeliac disease and wheat allergy are well known, but this is not the case for noncoeliac gluten sensitivity. It is also not clear whether noncoeliac gluten sensitivity is caused by consumption of gluten or by consumption of fermentable oligosaccharides, disaccharides, monosaccharides, and polyols. Randomized trials on noncoeliac gluten sensitivity in children are lacking and are hardly needed to evaluate its role in paediatric patients with gastroenterology to avoid the use of unnecessary restrictive diets in children and interference with proper diagnosis of coeliac disease.

Effect of gliadin on permeability of intestinal biopsy explants from celiac disease patients and patients with non-celiac gluten sensitivity

Background: Intestinal exposure to gliadin leads to zonulin upregulation and consequent disassembly of intercellular tight junctions and increased intestinal permeability. We aimed to study response to gliadin exposure, in terms of barrier function and cytokine secretion, using intestinal biopsies obtained from four groups: celiac patients with active disease (ACD), celiac patients in remission (RCD), non-celiac patients with gluten sensitivity (GS) and non-celiac controls (NC). Methods: Ex-vivo human duodenal biopsies were mounted in microsnapwells and luminally incubated with either gliadin or media alone. Changes in transepithelial electrical resistance were monitored over 120 min. Media was subsequently collected and cytokines quantified. Results: Intestinal explants from all groups (ACD (n = 6), RCD (n = 6), GS (n = 6), and NC (n = 5)) demonstrated a greater increase in permeability when exposed to gliadin vs. media alone. The increase in permeability in the ACD group was greater than in the RCD and NC groups. There was a greater increase in permeability in the GS group compared to the RCD group. There was no difference in permeability between the ACD and GS groups, between the RCD and NC groups, or between the NC and GS groups. IL-10 was significantly greater in the media of the NC group compared to the RCD and GS groups. Conclusions: Increased intestinal permeability after gliadin exposure occurs in all individuals. Following gliadin exposure, both patients with gluten sensitivity and those with active celiac disease demonstrate a greater increase in intestinal permeability than celiacs in disease remission. A higher concentration of IL-10 was measured in the media exposed to control explants compared to celiac disease in remission or gluten sensitivity.

The clinical response to gluten challenge: a review of the literature

The aim of this review was to identify, evaluate and summarize all relevant studies reporting on the clinical response to gluten challenge by adult or pediatric patients with suspected or diagnosed coeliac disease (CD) on a gluten-free diet. We evaluated the effect of gluten challenge on changes in symptoms, intestinal mucosa histology, and serum antibodies. A systematic electronic search was performed for studies published as of 1966 using PubMed and Scopus databases. In the reviewed studies, doses ranged from 0.2 to 30 g/day of wheat gluten or comprised a gluten-containing diet. The onset of symptoms upon gluten intake varied largely from days to months and did not parallel serum antibody or histological changes. Within 3 months of gluten challenge, 70%-100% of pediatric CD patients became positive for AGA-IgA and EMA-IgA antibodies and 50%-70% for AGA-IgG. A limited number of trials suggest that no more than half of adult patients developed positive AGA-IgA, EMA-IgA, tTG-IgA or DGP-IgA/IgG titers. Approximately 50%-100% of pediatric and adult patients experienced mucosal relapse of gluten provocation within 3 months, which was preceded by increased mucosal intra-epithelial lymphocytes within several days of challenge. A 3-month high-dose gluten challenge should be suitable to diagnose the majority of CD patients. In some cases prolonged challenge may be needed to verify diagnosis. Combination testing for antibodies and mucosal histology may fasten the diagnosis.

ACG clinical guidelines: diagnosis and management of celiac disease

This guideline presents recommendations for the diagnosis and management of patients with celiac disease. Celiac disease is an immune-based reaction to dietary gluten (storage protein for wheat, barley, and rye) that primarily affects the small intestine in those with a genetic predisposition and resolves with exclusion of gluten from the diet. There has been a substantial increase in the prevalence of celiac disease over the last 50 years and an increase in the rate of diagnosis in the last 10 years. Celiac disease can present with many symptoms, including typical gastrointestinal symptoms (e.g., diarrhea, steatorrhea, weight loss, bloating, flatulence, abdominal pain) and also non-gastrointestinal abnormalities (e.g., abnormal liver function tests, iron deficiency anemia, bone disease, skin disorders, and many other protean manifestations). Indeed, many individuals with celiac disease may have no symptoms at all. Celiac disease is usually detected by serologic testing of celiac-specific antibodies. The diagnosis is confirmed by duodenal mucosal biopsies. Both serology and biopsy should be performed on a gluten-containing diet. The treatment for celiac disease is primarily a gluten-free diet (GFD), which requires significant patient education, motivation, and follow-up. Non-responsive celiac disease occurs frequently, particularly in those diagnosed in adulthood. Persistent or recurring symptoms should lead to a review of the patient's original diagnosis to exclude alternative diagnoses, a review of the GFD to ensure there is no obvious gluten contamination, and serologic testing to confirm adherence with the GFD. In addition, evaluation for disorders associated with celiac disease that could cause persistent symptoms, such as microscopic colitis, pancreatic exocrine dysfunction, and complications of celiac disease, such as enteropathy-associated lymphoma or refractory celiac disease, should be entertained. Newer therapeutic modalities are being studied in clinical trials, but are not yet approved for use in practice. Given the incomplete response of many patients to a GFD-free diet as well as the difficulty of adherence to the GFD over the long term, development of new effective therapies for symptom control and reversal of inflammation and organ damage are needed. The prevalence of celiac disease is increasing worldwide and many patients with celiac disease remain undiagnosed, highlighting the need for improved strategies in the future for the optimal detection of patients.

Non-celiac gluten sensitivity

Gluten sensitivity has been best recognized and understood in the context of two conditions, celiac disease and wheat allergy. However, some individuals complain of symptoms in response to ingestion of "gluten," without histologic or serologic evidence of celiac disease or wheat allergy. The term non-celiac gluten sensitivity (NCGS) has been suggested for this condition, although a role for gluten proteins as the sole trigger of the associated symptoms remains to be established. This article reviews the available information regarding symptomatology, epidemiology and genetics, serology and histology, and in vitro and in vivo experimental data on the pathophysiology of NCGS.

The prevalence of celiac disease in the United States

OBJECTIVES

The prevalence of celiac disease (CD) in the United States is unknown. We sought to estimate CD prevalence nationwide by using a nationally representative sample.

METHODS

This study included 7,798 persons aged 6 years or older who participated in the National Health and Nutrition Examination Survey 2009-2010. Serum samples from all participants were tested for immunoglobulin A (IgA) tissue transglutaminase antibodies and, if findings were abnormal, also for IgA endomysial antibodies. Information about prior diagnosis of CD and use of a gluten-free diet (GFD) was obtained by direct interview. CD was defined as having either double-positive serology (serologically diagnosed CD) or a reported diagnosis of CD by a doctor or other health-care professional and being on a GFD (reported clinical diagnosis of CD).

RESULTS

CD was found in 35 participants, 29 of whom were unaware of their diagnosis. Median age was 45 years (interquartile range, 23-66 years); 20 were women and 29 were non-Hispanic white. The prevalence of CD in the United States was 0.71% (95% confidence interval (CI), 0.58-0.86%), with 1.01% (95% CI, 0.78-1.31%) among non-Hispanic whites. In all, 55 participants reported following a GFD, which corresponded to a prevalence of 0.63% (95% CI, 0.36-1.07%).

CONCLUSIONS

The prevalence of CD in the United States was 0.71% (1 in 141), similar to that found in several European countries. However, most cases were undiagnosed. CD was rare among minority groups but affected 1% of non-Hispanic whites. Most persons who were following a GFD did not have a diagnosis of CD.

A score that verifies adherence to a gluten-free diet: a cross-sectional, multicentre validation in real clinical life

A dietary interview performed by expert personnel is the best method to check whether patients with coeliac disease follow a strict gluten-free diet (GFD). We previously developed a score based on four fast and simple questions that can be administered even by non-expert personnel. The aim of the present study is to verify the reliability of our questionnaire in a new cohort of patients. The questionnaire has a five-level score. From March 2008 to January 2011, the questionnaire was administered to 141 coeliac patients on a GFD, who were undergoing re-evaluation. The score obtained was compared with persistence of both villous atrophy and endomysial antibodies (EMA). The rate of lower scores was higher among the patients with persistence of either villous atrophy (Fisher's exact, P < 0·001; test for trend, P < 0·001) or positive EMA (Fisher's exact, P = 0·001; test for trend, P = 0·018). Given that the coeliac patients have been well instructed on what a GFD means and on how to follow it, our questionnaire is a reliable and simple method to verify compliance to a GFD.

Assessing possible celiac disease by an HLA-DQ2-gliadin Tetramer Test

OBJECTIVES

Investigation of uncertain celiac disease (CD) in patients already on a gluten-free diet (GFD) is difficult. We evaluated HLA-DQ2-gliadin tetramers for detection of gluten-specific T cells in peripheral blood and histological changes in the duodenum after a short gluten challenge as a diagnostic tool.

METHODS

HLA-DQ2+ individuals on a GFD for at least 4 weeks were investigated; 35 with uncertain diagnosis, 13 CD patients, and 2 disease controls. All participants had a challenge with four slices of gluten-containing white bread, daily for 3 days (d1-d3). An esophagogastroduodenoscopy with biopsy sampling was done on d0 and d4. Biopsies were scored according to revised Marsh criteria. Peripheral blood CD4+ T cells were isolated, stained with HLA-DQ2-gliadin peptide tetramers, and analyzed by flow cytometry on d0 and d6.

RESULTS

After challenge, a positive tetramer test was seen in 11/13 CD patients. Four of these subjects also showed typical histological changes on challenge. Of the 35 patients with uncertain diagnosis, 3 were diagnosed with CD. Two of these three patients had both positive tetramer staining and histological changes in biopsies after challenge.

CONCLUSIONS

Tetramer staining for gluten-specific T cells is a sensitive method in detecting an immune response in CD patients after a short gluten challenge. The prevalence of CD in the group with self-prescribed GFD was about 10%.

What is the use of biopsy and antibodies in coeliac disease diagnosis?

The advent of highly sensitive and specific serological markers has led to some protagonists proposing that coeliac disease can be diagnosed without the need for a biopsy. However, this is an area of controversy. Lack of consensus about diagnostic degrees of histological change, paucity of symptoms, antibody-negative disease and immunodeficiency can make diagnosis difficult even with a biopsy. Conversely, an argument can be put forward for a 'no biopsy' approach based on the large number of patients with typical symptoms and positive serology who experience a diagnostic delay. In addition, endoscopy is not without discomfort. This article discusses the use of antibodies and duodenal biopsy within this context. Finally, we propose a pragmatic diagnostic algorithm for clinicians to use when investigating patients for coeliac disease.

When to reconsider the diagnosis of irritable bowel syndrome

Irritable bowel syndrome (IBS) is a highly prevalent disorder characterized by nonspecific symptoms that can mimic other common medical conditions. A careful history and physical examination may reveal clues that suggest a coexisting or alternative diagnosis, such as small intestinal bacterial overgrowth or celiac disease (CD). Testing for bacterial overgrowth has limitations, but emerging data suggest that antibiotics may be of some benefit in patients with IBS with diarrhea and bloating. CD seems to have a higher prevalence in patients with IBS. Some patients with IBS may have symptomatic improvement on gluten-restricted diets, without histologic or serologic evidence of CD.

Are we not over-estimating the prevalence of coeliac disease in the general population?

Until the 1980s, coeliac disease was considered to be a rare disease, but in the 1990s it became clear that it was a frequent condition. Recently, it was suggested to affect 1 out of 100 subjects in the Western world. To understand what the true prevalence of coeliac disease is in the general population, we conducted a systematic review of published papers. The overall prevalence of coeliac disease in the general population appears to be around 1/160 (6.2‰), but this figure varies widely according to the diagnostic criteria used in the original papers. Prevalence obtained with tissue transglutaminase antibodies only was markedly higher than that obtained through a histological diagnosis. We conclude that the prevalence of coeliac disease in the general population has been over-estimated. This is mainly due to tissue transglutaminase antibodies being used as the only diagnostic tool.

Mucosal recovery and mortality in adults with celiac disease after treatment with a gluten-free diet

OBJECTIVES

Clinical response is typically observed in most adults with celiac disease (CD) after treatment with a gluten-free diet (GFD). The rate of mucosal recovery is less certain. The aims of this study were (1) to estimate the rate of mucosal recovery after GFD in a cohort of adults with CD, and (2) to assess the clinical implications of persistent mucosal damage after GFD.

METHODS

The study group included adults with biopsy-proven CD evaluated at the Mayo Clinic who had duodenal biopsies at diagnosis and at least one follow-up intestinal biopsy to assess mucosal recovery after starting a GFD. The primary outcomes of interest were mucosal recovery and all-cause mortality.

RESULTS

Of 381 adults with biopsy-proven CD, 241 (73% women) had both a diagnostic and follow-up biopsy available for re-review. Among these 241, the Kaplan-Meier rate of confirmed mucosal recovery at 2 years following diagnosis was 34% (95% confidence interval (CI): 27-40%), and at 5 years was 66% (95% CI: 58-74%). Most patients (82%) had some clinical response to GFD, but it was not a reliable marker of mucosal recovery (P=0.7). Serological response was associated with confirmed mucosal recovery (P=0.01). Poor compliance to GFD (P<0.01), severe CD defined by diarrhea and weight loss (P<0.001), and total villous atrophy at diagnosis (P<0.001) were strongly associated with persistent mucosal damage. There was a trend toward an association between achievement of mucosal recovery and a reduced rate of all-cause mortality (hazard ratio=0.13, 95% CI: 0.02-1.06, P=0.06), adjusted for gender and age.

CONCLUSIONS

Mucosal recovery was absent in a substantial portion of adults with CD after treatment with a GFD. There was a borderline significant association between confirmed mucosal recovery (vs. persistent damage) and reduced mortality independent of age and gender. Systematic follow-up with intestinal biopsies may be advisable in patients diagnosed with CD as adults.

Pediatric celiac disease

PURPOSE OF REVIEW

Celiac disease is an extremely common, although underdiagnosed, disorder. Knowledge about the varied clinical manifestations and the proper approach to screening and diagnosing celiac disease will lead to appropriate early intervention in affected children

RECENT FINDINGS

New age-dependent algorithms are emerging to properly screen for celiac disease. There is new evidence on the patchy nature of celiac disease supporting the practice of multiple duodenal biopsies including the bulb of the duodenum. Therapeutic dietary compliance, particularly in asymptomatic children, can be poor, and therefore, the involvement of a dietician trained in celiac disease is instrumental in keeping patients up to date with dietary guidelines and to improve their compliance to the diet. Expanding knowledge about the pathogenesis of celiac disease has led to the development of investigational therapeutic alternatives to the gluten-free diet. Ongoing clinical trials are evaluating methods of celiac disease prevention in at-risk infants.

SUMMARY

This review aims at outlining the different manifestations of celiac disease in children as well as a step-wise approach to screen and diagnose the disease. A better understanding of the pathogenic mechanisms of celiac disease is paving the way to innovative diagnostic tools, preventive strategies, and therapeutic interventions alternative to a gluten-free diet.

The impact of misdiagnosing celiac disease at a referral centre

In the past few years, the number of celiac disease diagnoses not confirmed at the Fondazione IRCCS Policlinico San Matteo, Pavia, Italy, a tertiary referral centre, was particularly high. Therefore, a decision was made to investigate the reasons why these diagnoses were wrong and by whom they had been made. The clinical histories of all celiac patients referred to the centre were re-evaluated. Between December 1998 and January 2007, 614 patients who were diagnosed at other institutions and presumed to be affected by celiac disease attended the tertiary referral outpatient clinic. The histological and serological results allowed for confirmation the diagnosis in 434 patients. In the remaining 180 patients, the initial diagnosis of celiac disease could not be confirmed; therefore, the patients were re-investigated. After re-evaluation, the diagnosis of celiac disease was confirmed in only 61 of these 180 cases. The reasons for incorrect initial diagnosis were analyzed. A mere 80% correct diagnosis rate is a very disappointing result. Although it should be obvious that celiac disease must be investigated with duodenal biopsies and celiac antibody testing, this well-known strategy is not always followed, probably resulting in an incorrect diagnosis.

Enteroscopy in the diagnosis and management of celiac disease

Esophagogastroduodenoscopy (EGD) with 3 to 6 biopsies in the descending duodenum is the gold standard for the diagnosis of celiac disease. At the time of the first diagnosis of celiac disease, an extensive evaluation of the small bowel is not recommended. However, video capsule endoscopy, because of its good sensitivity and specificity in recognizing the Endoscopic features of celiac disease, can be considered a valid alternative to EGD in patients unable or unwilling to undergo EGD with biopsies. Capsule endoscopy is also a possible option in selected cases with strong suspicion of celiac disease but negative first-line tests. In evaluating patients with refractory or complicated celiac disease, in whom a complete evaluation of the small bowel is mandatory (at least in refractory celiac disease type II patients) because of the possible presence of complications beyond the reach of conventional endoscopes, both capsule endoscopy and balloon-assisted enteroscopy have been found to be helpful. In these patients, capsule endoscopy offers several advantages: it is well tolerated, it allows inspection of the entire small bowel, and it is able to recognize subtle mucosal changes. However, in this setting, capsule endoscopy should ideally be coupled with imaging techniques that provide important information about the thickness of the wall of the intestine and about extraluminal abnormalities. Although deep enteroscopy (such as balloon enteroscopy) is expensive, time-consuming, and potentially risky in these frail patients, they may have a key role, because they make it possible to take tissue samples from deep in the small intestine.