The Oslo definitions for coeliac disease and related terms

Other Dietary Confounders: FODMAPS et al

BACKGROUND

While it is well documented and widely appreciated that ingestion of wheat (and less so rye and barley) is associated with gastrointestinal symptoms such as bloating or abdominal pain, the component of wheat to which such an effect is attributed is less well established.

KEY MESSAGES

Wheat is a complex of proteins (80% gluten, 20% metabolic proteins), carbohydrates (starch, non-starch polysaccharides, fructans), lipids and other components. The majority of attention has focused on gluten as the culprit in triggering symptoms, but re-challenge studies have nearly all used wheat flour-related products (such as bread) as the stimulus. When carbohydrate-deplete gluten was used as the challenge agent, gluten-specific feelings of depression and not gut symptoms were observed in those who fulfilled strict criteria of 'non-coeliac gluten sensitivity', thereby underlining the complexity of cereals and of undertaking research in this area. Candidate components other than gluten include poorly absorbed oligosaccharides (mainly fructans), non-gluten wheat proteins such as amylase-trypsin inhibitors or wheat germ agglutinin, and exorphins released during the digestion of gluten. Specific biological and/or clinical effects associated with gluten-free diets or wheat ingestion need to be carefully dissected before attribution to gluten can be claimed.

CONCLUSIONS

Currently, coeliac disease is the only common condition that has been unequivocally linked to gluten. Inaccurate attribution will be associated with suboptimal therapeutic advice and at least partly underlies the current gluten-free epidemic gripping the Western world.

Celiac disease screening in southern and East Asia

Until 1970s, celiac disease (CD) was considered to be an uncommon disease except in Western Europe. The global epidemiology of CD continues to evolve with improvement in the diagnostic tests, simplification of the diagnostic criteria and increase in awareness about the disease. The Asian region is currently at the crossroads of the frontier of knowledge and awareness of CD. In many Asian nations, CD is still considered to be either nonexistent or very rare. A notable exception is India, where CD has been well recognized, especially in the northern part, and 2 population-based studies have revealed a prevalence of 0.3-1.04%. Initial reports from Malaysia, China, Japan and Singapore suggest the existence of CD in these countries. Furthermore, a meta-analysis of the predisposing factors predicts a high probability of occurrence of CD in fair numbers in China. There are no formal reports on CD from Malaysia, Indonesia, Korea, Taiwan and many other nations in this region. With the impending CD epidemic in Asia, there are many challenges. Some of the efforts which are required include determination of prevalence of CD across the region, spreading of awareness among physicians and patients, training of dieticians for proper counseling and supervision of patients, creation of gluten-free food infrastructure in the food supply and creation of patient advocacy organizations. Although the absolute number of patients with CD at present is not very large, this number is expected to increase over the next few years/decades. It is thus appropriate that the medical community across Asia define the extent of the problem and get prepared to handle the impending CD epidemic.

Extraintestinal manifestations of celiac disease

Case finding for celiac disease (CD) is becoming increasingly common practice and is conducted in a wide range of clinical situations ranging from the presence of gastrointestinal symptoms to failure to thrive in children, prolonged fatigue, unexpected weight loss and anemia. Case finding is also performed in associated conditions, such as autoimmune thyroid disease, dermatitis herpetiformis and type 1 diabetes, as well as in patients with irritable bowel syndrome, unexplained neuropsychiatric disorders and first-degree relatives of patients with diagnosed CD. This aggressive active case finding has dramatically changed the clinical characteristics of newly diagnosed patients. For instance, higher numbers of patients who present with extraintestinal symptoms are now being diagnosed with CD. Current recommendations state that due to a high risk for complications if the disease remains undiagnosed, patients with extraintestinal symptoms due to CD require appropriate diagnosis and treatment. Despite criticism regarding the cost-effectiveness of case finding in CD, such an aggressive approach has been considered cost-effective for high-risk patients. The diagnosis of CD among patients with extraintestinal symptoms requires a high degree of awareness of the clinical conditions that carry a high risk for underlying CD. Also, understanding the correct use of specific serology and duodenal histology is key for an appropriate diagnostic approach. Both procedures combined are able to confirm diagnosis in the vast majority of cases. However, in certain circumstances, serology and even duodenal histology cannot confirm or rule out CD. A common cause of negative IgA serology is IgA deficiency. For such eventuality, IgG-based serological tests can help confirm the diagnosis. Importantly, some histologically diagnosed cases still remain seronegative despite exclusion of IgA deficiency. On the other hand, duodenal histology may be normal despite the presence of CD-specific antibodies and active CD. This has been clearly demonstrated in some cases of untreated dermatitis herpetiformis, but may also be due to the patchy condition of CD or lesions that are not adequately recognized by nonexpert endoscopists and/or pathologists. The effectiveness of agluten-free diet depends on the clinical end point addressed. A good example is the outcome of bone loss. While risk for fracture normalizes after the first year of dietary treatment, bone parameters measured by densitometry may not be normalized in the long-term follow-up. Moreover, it is still unclear how far an early gluten-free diet will positively affect associated autoimmune diseases like type 1 diabetes and autoimmune thyroiditis.

Motility alterations in celiac disease and non-celiac gluten sensitivity

Regulation of gut motility is complex and involves neuromuscular, immune and environmental mechanisms. It is well established that patients with celiac disease (CD) often display gut dysmotility. Studies have shown the presence of disturbed esophageal motility, altered gastric emptying, and dysmotility of the small intestine, gallbladder and colon in untreated CD. Most of these motor abnormalities resolve after a strict gluten-free diet, suggesting that mechanisms related to the inflammatory condition and disease process are responsible for the motor dysfunction. Motility abnormalities are also a hallmark of functional bowel disorders such as irritable bowel syndrome (IBS), where it has been proposed as underlying mechanism for symptom generation (diarrhea, constipation, bloating). Non-celiac gluten sensitivity (NCGS) is a poorly defined entity, mostly self-diagnosed, that presents clinically with IBS symptoms in the absence of specific celiac markers. Patients with NCGS are believed to react symptomatically to wheat components, and some studies have proposed the presence of low-grade inflammation in these patients. There is little information regarding the functional characterization of these patients before and after a gluten-free diet. A study suggested the presence of altered gastrointestinal transit in NCGS patients who also have a high prevalence of nonspecific anti-gliadin antibodies. Results of an ongoing clinical study in NCGS patients with positive anti-gliadin antibodies before and after a gluten-free diet will be discussed. Elucidating the mechanisms for symptom generation in NCGS patients is important to find new therapeutic alternatives to the burden of imposing a strict gluten-free diet in patients who do not have CD.

Videocapsule endoscopy in celiac disease: indications and timing

BACKGROUND

Because of its technical characteristics (i.e. 8-fold magnification, capability to inspect the entire small bowel) and minimal invasiveness, videocapsule endoscopy (VCE) has been proposed as a useful tool for managing patients with celiac disease (CD).

KEY MESSAGES

Although VCE has been found to be highly sensitive and specific in identifying CD endoscopic markers, it is still inadequate to replace esophagogastroduodenoscopy (EGD) with biopsies in the diagnosis of CD. Nevertheless, it represents a reliable alternative in patients unable or unwilling to undergo EGD. Up to now, available studies have failed to identify any correlation between the length of small bowel involvement and the severity of symptoms. The available evidence on the use of VCE in diagnosing CD in equivocal cases (patients with positive serology and negative or nonspecific histology or those with negative serology and histologically proven villous atrophy) is limited, and its role is still under discussion. In CD patients not improving on gluten-free diet, a complete workup is necessary. In patients with nonresponsive (NRCD) or refractory CD (RCD), VCE has been shown to be able not only to detect significant findings, driving further management, but also to rule out major complications. Nevertheless, in this setting, the inability of VCE to take tissue samples and the risk of capsule retention can represent major limitations.

CONCLUSIONS

At the present time, for diagnostic purposes, VCE can be proposed only in patients unable or unwilling to undergo EGD, whereas it could be useful in some equivocal cases. Conversely, there is no room for VCE either to estimate the length of the small bowel affected by villous atrophy or to follow up patients improving on gluten-free diet. In patients with NRCD or RCD, VCE can play a role, but it should be combined with other diagnostic techniques.

Celiac disease and the gluten-free diet: consequences and recommendations for improvement

BACKGROUND

Celiac disease (CD) is a chronic small intestinal immune-mediated enteropathy precipitated by exposure to dietary gluten in genetically susceptible individuals. CD-related enteropathy leads to multiple nutritional deficiencies involving macro- and micronutrients. Currently, medical nutrition therapy consisting of the gluten-free diet (GFD) is the only accepted treatment for CD.

KEY MESSAGES

The GFD is the cornerstone of treatment for CD. Prior published studies have concluded that maintenance of the GFD results in improvement of the majority of nutritional deficiencies. In the past, counseling for CD focused mainly on the elimination of gluten in the diet. However, the GFD is not without its inadequacies; compliance to the GFD may result in certain deficiencies such as fiber, B vitamins, iron, and trace minerals. Paucity of fortified gluten-free foods may be responsible for certain deficiencies which develop on the GFD. Weight gain and obesity have been added to the list of nutritional consequences while on the GFD and have been partially attributed to hypercaloric content of commercially available gluten-free foods. Follow-up of patients diagnosed with CD after starting the GFD has been reported to be irregular and, hence, less than ideal.

CONCLUSIONS

Monitoring of the nutritional status using blood tests and use of appropriate gluten-free supplementation are integral components in the management of CD. The ideal GFD should be nutrient-dense with naturally gluten-free foods, balanced with macro- and micronutrients, reasonably priced, and easily accessible. Rotation of the pseudo-cereals provides a good source of complex carbohydrates, protein, fiber, fatty acids, vitamins and minerals. Fortification/enrichment of commonly consumed gluten-free commercial grain products should be encouraged. Dietitians specializing in CD play a critical role in the education and maintenance of the GFD for patients with CD.

Living gluten-free: adherence, knowledge, lifestyle adaptations and feelings towards a gluten-free diet

BACKGROUND

A gluten-free diet (GFD) requires tremendous dedication, involving substantive changes to diet and lifestyle that may have a significant impact upon quality of life. The present study aimed io assess dietary adherence, knowledge of a GFD, and the emotional and lifestyle impact of a GFD.

METHODS

Community dwelling adults following a GFD completed a questionnaire with items related to reasons for avoiding gluten, diagnostic testing, GFD adherence, knowledge and sources of information about a GFD, the Work and Social Adjustment Scale, and the effect of a GFD diet on lifestyle, feelings and behaviours.

RESULTS

Strict GFD adherence among the 222 coeliac disease (CD) patients was 56%. Non-CD individuals (n = 38) were more likely to intentionally ingest gluten (odds ratio = 3.7; 95% confidence interval = 1.4-9.4). The adverse impact of a GFD was modest but most pronounced in the social domain. Eating shifted from the public to the domestic sphere and there were feelings of social isolation. Affective responses reflected resilience because acceptance and relief were experienced more commonly than anxiety or anger. Non-CD respondents were less knowledgeable and less likely to consult health professionals. They experienced less anger and depression and greater pleasure in eating than CD respondents.

CONCLUSIONS

The findings obtained in the present suggest there is good potential for positive adaptation to the demands of a GFD; nevertheless, there is a measurable degree of social impairment that merits further study. The GFD may be a viable treatment option for conditions other than CD; however, education strategies regarding the need for diagnostic testing to exclude CD are required.

A study evaluating the bidirectional relationship between inflammatory bowel disease and self-reported non-celiac gluten sensitivity

BACKGROUND

Non-celiac gluten sensitivity and the associated use of a gluten-free diet (GFD) are perceived to belong to the spectrum of irritable bowel syndrome (IBS). However, recent reports suggest substantial use of a GFD in inflammatory bowel disease (IBD). We assessed the bidirectional relationship between IBD and self-reported non-celiac gluten sensitivity (SR-NCGS).

METHODS

A cross-sectional questionnaire screened for SR-NCGS and the use of a GFD in 4 groups: ulcerative colitis (n = 75), Crohn's disease (n = 70), IBS (n = 59), and dyspeptic controls (n = 109). We also assessed diagnostic outcomes for IBD in 200 patients presenting with SR-NCGS.

RESULTS

The prevalence of SR-NCGS was 42.4% (n = 25/59) for IBS, followed by 27.6% (n = 40/145) for IBD, and least among dyspeptic controls at 17.4% (n = 19/109); P = 0.015. The current use of a GFD was 11.9% (n = 7/59) for IBS, 6.2% (n = 9/145) for IBD, and 0.9% (1/109) for dyspeptic controls; P = 0.02. No differences were established between ulcerative colitis and Crohn's disease. However, Crohn's disease patients with SR-NCGS were significantly more likely to have stricturing disease (40.9% versus 18.9%, P = 0.046), and higher mean Crohn's Disease Activity Index score (228.1 versus 133.3, P = 0.002), than those without SR-NCGS. Analysis of 200 cases presenting with SR-NCGS suggested that 98.5% (n = 197) could be dietary-related IBS. However, 1.5% (n = 3) were found to have IBD; such patients had associated alarm symptoms, and/or abnormal blood parameters, prompting colonic investigations.

CONCLUSIONS

SR-NCGS is not only exclusive to IBS but also associated with IBD, where its presence may be reflecting severe or stricturing disease. Randomized studies are required to further delineate the nature of this relationship and clarify whether a GFD is a valuable dietetic intervention in selected IBD patients.

Screening for celiac disease in the general population and in high-risk groups

BACKGROUND

Celiac disease (CD) occurs in approximately 1% of the Western population. It is a lifelong disorder that is associated with impaired quality of life (QOL) and an excessive risk of comorbidity and death.

OBJECTIVES

To review the literature on screening for CD in relation to the current World Health Organization (WHO) criteria for mass screening.

METHODS

We performed a PubMed search to identify indexed papers on CD screening with a publication date from 1900 until 1 June 2014. When we deemed an abstract relevant, we read the corresponding paper in detail.

RESULTS

CD fulfills several WHO criteria for mass screening (high prevalence, available treatment and difficult clinical detection), but it has not yet been established that treatment of asymptomatic CD may reduce the excessive risk of severe complications, leading to higher QOL nor that it is cost-effective.

CONCLUSIONS

Current evidence is not sufficient to support mass screening for CD, but active case-finding may be appropriate, as we recognize that most patients with CD will still be missed by this strategy. Although proof of benefit is still lacking, screening for CD may be appropriate in high-risk groups.

The gluten-free diet and its current application in coeliac disease and dermatitis herpetiformis

BACKGROUND

A gluten-free diet (GFD) is currently the only available therapy for coeliac disease (CD).

OBJECTIVES

We aim to review the literature on the GFD, the gluten content in naturally gluten-free (GF) and commercially available GF food, standards and legislation concerning the gluten content of foods, and the vitamins and mineral content of a GFD.

METHODS

We carried out a PubMed search for the following terms: Gluten, GFD and food, education, vitamins, minerals, calcium, Codex wheat starch and oats. Relevant papers were reviewed and for each topic a consensus among the authors was obtained.

CONCLUSION

Patients with CD should avoid gluten and maintain a balanced diet to ensure an adequate intake of nutrients, vitamins, fibre and calcium. A GFD improves symptoms in most patients with CD. The practicalities of this however, are difficult, as (i) many processed foods are contaminated with gluten, (ii) staple GF foods are not widely available, and (iii) the GF substitutes are often expensive. Furthermore, (iv) the restrictions of the diet may adversely affect social interactions and quality of life. The inclusion of oats and wheat starch in the diet remains controversial.

Transamidation of gluten proteins during the bread-making process of wheat flour to produce breads with less immunoreactive gluten

Due to an increasing incidence of celiac disease (CD) and other gluten-related disorders, different gluten-free breads have been developed using starches and additives as a substitute for gluten. Thus, patients miss not only the taste and aroma of wheat bread but also risk their sensitive intestines. Therefore, modifying gluten to avoid an immune response in CD and its application to baking is in progress. The aim of the study was to enzymatically modify gluten on wheat flour, during bread-making avoiding the use of additives, to reduce immunoreactivity, preserving its properties. Microbial transglutaminase (mTG) or chymotrypsin (ChT) was used to bind lysine or valine to gluten proteins in a model system. The best conditions were directly applied to wheat flour for bread-making with and without punching at 45 min. Subsequently, the rheological properties of the doughs, specific volume of the loaves, immunoreactive gluten content and modification of the extracted proteins were evaluated. ChT-treated breads presented a better appearance with a more homogeneous crumb, higher specific volume values (3.34-4.25 cm(3) g(-1)) and higher reactive gluten reduction (up to 71%) than the mTG-treated ones (1.23-2.66 cm(3) g(-1)) with only a 42% reactive gluten reduction. Thus, transpeptidation during bread-making is a promising technology, although it is necessary to improve the modification process to obtain the reactive gluten reduction required in breads for the treatment of CD patients and other gluten-related disorders.

Sourdough fermentation of wheat flour does not prevent the interaction of transglutaminase 2 with α2-gliadin or gluten

The enzyme transglutaminase 2 (TG2) plays a crucial role in the initiation of celiac disease by catalyzing the deamidation of gluten peptides. In susceptible individuals, the deamidated peptides initiate an immune response leading to celiac disease. Several studies have addressed lactic fermentation plus addition of enzymes as a means to degrade gluten in order to prevent adverse response in celiacs. Processing for complete gluten degradation is often harsh and is not likely to yield products that are of comparable characteristics as their gluten-containing counterparts. We are concerned that incomplete degradation of gluten may have adverse effects because it leads to more available TG2-binding sites on gluten peptides. Therefore, we have investigated how lactic acid fermentation affects the potential binding of TG2 to gluten protein in wheat flour by means of estimating TG2-mediated transamidation in addition to measuring the available TG2-binding motif QLP, in α₂-gliadin. We show that lactic fermentation of wheat flour, as slurry or as part of sourdough bread, did not decrease the TG2-mediated transamidation, in the presence of a primary amine, to an efficient level (73%–102% of unfermented flour). Nor did the lactic fermentation decrease the available TG2 binding motif QLP in α₂-gliadin to a sufficient extent in sourdough bread (73%–122% of unfermented control) to be useful for celiac safe food.

Diet and irritable bowel syndrome

PURPOSE

of review Those who suffer from irritable bowel syndrome (IBS) have long reported the frequent precipitation of their symptoms in relation to food ingestion and have often been convinced that certain foods were especially problematic. However, until very recently, research on the responses to food or individual dietary constituents, in IBS, has been scarce. This review addresses recent literature on diet and IBS.

RECENT FINDINGS

The complexity of food-symptom interactions in IBS is being revealed in recent and ongoing research. Such studies have revealed the variable effects of fibre in IBS and the susceptibility of IBS individuals to the ingestion of poorly digested and absorbed carbohydrates. The latter has led to the widespread adoption of the low-fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAPs) diet. Less certain is the role of another widely adopted dietary strategy, gluten restriction. Diet-microbe interactions are critical to the homeostasis of the gut microbiome in health and may well be disturbed in disease; enthusiasm continues, therefore, for the use of probiotics in IBS.

SUMMARY

Food is a common precipitant of symptoms in IBS and recent research has focused on the role(s) of individual dietary constituents in IBS and on fibre, FODMAPs, gluten and probiotics, in particular. Each may have a role in certain IBS sufferers.

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.

A Grounded Guide to Gluten: How Modern Genotypes and Processing Impact Wheat Sensitivity

The role of wheat, and particularly of gluten protein, in our diet has recently been scrutinized. This article provides a summary of the main pathologies related to wheat in the human body, including celiac disease, wheat allergy, nonceliac wheat sensitivity, fructose malabsorption, and irritable bowel syndrome. Differences in reactivity are discussed for ancient, heritage, and modern wheats. Due to large variability among species and genotypes, it might be feasible to select wheat varieties with lower amounts and fewer types of reactive prolamins and fructans. Einkorn is promising for producing fewer immunotoxic effects in a number of celiac research studies. Additionally, the impact of wheat processing methods on wheat sensitivity is reviewed. Research indicates that germination and fermentation technologies can effectively alter certain immunoreactive components. For individuals with wheat sensitivity, less-reactive wheat products can slow down disease development and improve quality of life. While research has not proven causation in the increase in wheat sensitivity over the last decades, modern wheat processing may have increased exposure to immunoreactive compounds. More research is necessary to understand the influence of modern wheat cultivars on epidemiological change.

High prevalence of post-partum depression in women with coeliac disease

AIM: To explore the prevalence of post-partum depression (PPD) in coeliac disease (CD).

METHODS: We performed a case-control study evaluating the prevalence of PPD in CD patients on gluten-free diet (GFD) compared to that of healthy subjects experiencing a recent delivery. All participants were interviewed about menstrual features, modality and outcome of delivery and were evaluated for PPD by Edinburgh Postnatal Depression Scale (EPDS).

RESULTS: The study included 70 CD patients on GFD (group A) and 70 controls (group B). PPD was present in 47.1% of CD women and in 14.3% of controls (P < 0.01; OR = 3.3). Mean EPDS score was higher in CD compared to the controls (mean score: group A 9.9 ± 5.9; group B 6.7 ± 3.7; P < 0.01). A significant association was observed between PPD and menstrual disorders in CD (69.7% vs 18.9%; P < 0.001; OR = 3.6).

CONCLUSION: PPD is frequent in CD women on GFD, particularly in those with previous menstrual disorders. We suggest screening for PPD in CD for early detection and treatment of this condition.

Association between coeliac disease and psoriasis: Italian primary care multicentre study

BACKGROUND

Studies assessing the association between coeliac disease (CD) and psoriasis show conflicting results.

OBJECTIVE

To assess in the primary care setting the prevalence of CD in patients with psoriasis and the response to a gluten-free diet (GFD) in subjects with psoriasis and CD.

METHODS

We enrolled 218 patients with psoriasis and 264 controls. Coeliac screening was carried out in all subjects (Eurospital, Trieste, Italy). In subjects with a positive serology, the diagnosis of CD was confirmed histologically.

RESULTS

Nine (4.1%) psoriatic patients had positive anti-tissue transglutaminase antibodies compared to only 1 among controls (0.4%, p < 0.05; OR 2.03, 95% CI 1.42-90.11). The diagnosis of CD was confirmed histologically in all 10 subjects. At 6 months GFD was associated with a great improvement of skin lesions in 7 out of 8 patients with psoriasis.

CONCLUSION

Our multicentre primary care study showed an high prevalence of CD in psoriasis and an improvement of skin lesions in CD under GFD.

Review article: the aetiology, diagnosis, mechanisms and clinical evidence for food intolerance

BACKGROUND

Food intolerance is non-immunological and is often associated with gastrointestinal symptoms.

AIM

To focus on food intolerance associated with gastrointestinal symptoms and critically appraise the literature in relation to aetiology, diagnosis, mechanisms and clinical evidence.

METHODS

A search using the terms and variants of food intolerance, lactose, FODMAP, gluten, food chemicals within Pubmed, Embase and Scopus was carried out and restricted to human studies published in English. Additionally, references from relevant papers were hand searched for other appropriate studies.

RESULTS

Food intolerance affects 15-20% of the population and may be due to pharmacological effects of food components, noncoeliac gluten sensitivity or enzyme and transport defects. There have been significant advances in understanding the scientific basis of gastrointestinal food intolerance due to short-chain fermentable carbohydrates (FODMAPs). The most helpful diagnostic test for food intolerance is food exclusion to achieve symptom improvement followed by gradual food reintroduction. A low FODMAP diet is effective, however, it affects the gastrointestinal microbiota and FODMAP reintroduction to tolerance is part of the management strategy.

CONCLUSIONS

There is increasing evidence for using a low FODMAP diet in the management of functional gastrointestinal symptoms where food intolerance is suspected. Exclusion diets should be used for as short a time as possible to induce symptom improvement, and should be followed by gradual food reintroduction to establish individual tolerance. This will increase dietary variety, ensure nutritional adequacy and minimise impact on the gastrointestinal microbiota.

Age at gluten introduction and risk of celiac disease

OBJECTIVES

The goal of this study was to determine whether age at introduction to gluten was associated with risk for celiac disease (CD) in genetically predisposed children.

METHODS

TEDDY (The Environmental Determinants of Diabetes in the Young) is a prospective birth cohort study. Newborn infants (N = 6436) screened for high-risk HLA-genotypes for CD were followed up in Finland, Germany, Sweden, and the United States. Information about infant feeding was collected at clinical visits every third month. The first outcome was persistent positive for tissue transglutaminase autoantibodies (tTGA), the marker for CD. The second outcome was CD, defined as either a diagnosis based on intestinal biopsy results or on persistently high levels of tTGA.

RESULTS

Swedish children were introduced to gluten earlier (median: 21.7 weeks) compared with children from Finland (median: 26.1 weeks), Germany, and the United States (both median: 30.4 weeks) (P < .0001). During a median follow-up of 5.0 years (range: 1.7-8.8 years), 773 (12%) children developed tTGA and 307 (5%) developed CD. Swedish children were at increased risk for tTGA (hazard ratio: 1.74 [95% CI: 1.47-2.06]) and CD (hazard ratio: 1.76 [95% CI: 1.34-2.24]) compared with US children, respectively (P < .0001).Gluten introduction before 17 weeks or later than 26 weeks was not associated with increased risk for tTGA or CD, adjusted for country, HLA, gender, and family history of CD, neither in the overall analysis nor on a country-level comparison.

CONCLUSIONS

In TEDDY, the time to first introduction to gluten introduction was not an independent risk factor for developing CD.

Metabolic syndrome in patients with coeliac disease on a gluten-free diet

BACKGROUND

Several studies have shown that weight changes are common in patients with coeliac disease after starting a gluten-free diet (GFD), but data on the prevalence of metabolic syndrome in this population are still scarce.

AIMS

To assess the prevalence of metabolic syndrome in patients with CD at diagnosis and 1 year after starting GFD.

METHODS

We enrolled all consecutive patients with newly diagnosed coeliac disease (CD) who were referred to our third-level CD Unit. For all patients we collected: waist circumference, BMI, blood pressure, lipid profile (HDL cholesterol, triglycerides) and levels of blood glucose. Diagnosis of metabolic syndrome was made according to the International Diabetes Federation (IDF) criteria for European countries. The prevalence of metabolic syndrome was re-assessed after 12 months of GFD.

RESULTS

Ninety-eight patients with CD were assessed, two patients with CD (2%) fulfilled the diagnostic criteria for metabolic syndrome at diagnosis and 29 patients (29.5%) after 12 months of GFD (P < 0.01; OR: 20). With regard to metabolic syndrome sub-categories 1 year after GFD compared to baseline respectively: 72 vs. 48 patients exceeded waist circumference cut-off (P < 0.01; OR: 2.8); 18 vs. 4 patients had high blood pressure (P < 0.01; OR: 5.2); 25 vs. 7 patients exceeded glycemic threshold (P = 0.01; OR: 4.4); 34 vs. 32 patients with CD had reduced levels of HDL cholesterol (P = 0.7); and 16 vs. 7 patients had high levels of triglycerides (P = 0.05).

CONCLUSIONS

Patients with coeliac disease show a high risk of metabolic syndrome 1 year after starting a gluten-free diet. We suggest that an in-depth nutritional assessment is undertaken for all patients with coeliac disease.

What a practitioner needs to know about celiac disease?

Celiac disease (CD) is an immune-mediated systemic disorder elicited by gluten and related prolamines in genetically susceptible individuals and is characterized by the presence of a variable combination of gluten-dependent clinical manifestations, CD-specific antibodies, HLA-DQ2 or HLA-DQ8 haplotypes and enteropathy. CD is triggered by wheat gluten and related prolamines in barley and rye. Worldwide, the disease affects approximately 1 % of the general population. Clinical features of CD vary considerably. Intestinal symptoms are more common in young children. In older children extra intestinal manifestations affecting almost all organs are seen. IgA tTG antibody, upper GI endoscopy with histological analysis of multiple biopsies of the duodenum and in selected cases HLA DQ2 and DQ8 positivity and endomysial antibodies (EMA) are needed for diagnosis. Currently, the only treatment for CD is a life-long gluten-free diet (GFD). Strict avoidance of wheat, rye, barley and their derivatives will result in intestinal healing and relief of symptoms for the majority of individuals with CD. The GFD is simple in principle, however, completely eliminating all foods and ingredients containing wheat, rye, barley, and most commercial oats can be very challenging. Newly diagnosed CD children should undergo testing and treatment for micronutrient deficiencies specially iron, folic acid, vitamin D, and vitamin B12. Long-term monitoring and follow up of patients with CD is necessary.

The present and the future in the diagnosis and management of celiac disease

Celiac disease is an autoimmune enteropathy caused by gluten in genetically predisposed individuals. In celiac disease, adaptive and innate immune activation results in intestinal damage and a wide range of clinical manifestations. In the past, celiac disease was thought to result in signs and symptoms solely related to the gastrointestinal tract. Now, more than half of the adult population presents with extra-intestinal manifestations that can also be expected to improve on a gluten-free diet. For this reason, it is recommended that physicians have a low threshold of suspicion for celiac disease. Current knowledge of the immune pathogenesis of this autoimmune disease has served as a catalyst for the development of novel diagnostic tools and therapeutics. Over the years, highly sensitive and specific serological assays, in addition to genetic markers, have been found to target specific steps in the cascade pathway of celiac disease. Also the advent of the gluten challenge has enabled experts to design diagnostic algorithms and monitor clinical responses in clinical trials. The gluten challenge has provided substantial benefit in the advance of novel therapeutics as an adjuvant treatment to the gluten free diet. Generally, a strict gluten-free diet is highly burdensome to patients and can be limited in its efficacy. Alternative therapies-including gluten modification, modulation of intestinal permeability and immune response-could be central to the future treatment of celiac disease.

The diagnosis and treatment of celiac disease

BACKGROUND

Celiac disease is an inflammatory disease of, the small intestine with a prevalence of roughly 0.5%-1%. Its symptoms arise in response to gluten consumption by genetically predisposed persons (HLA-DQ2/8). The autoantigen tissue transglutaminase (TG2) plays an important role in the pathogenesis of celiac disease.

METHOD

Selective review of pertinent literature, including guidelines from Germany and abroad.

RESULTS

Celiac disease can present at any age with gastrointestinal or extraintestinal manifestations (e.g., malabsorption or Duhring's dermatitis herpetiformis); it can also be found in association with other (auto-)immune diseases, such as type 1 diabetes. Most cases are oligosymptomatic. The wide differential diagnosis includes food intolerances, intestinal infections, and irritable bowel syndrome, among other conditions. The definitive diagnosis requires the demonstration of celiac disease-specific autoantibody to TG2 (endomysium), which is over 90% sensitive and far over 90% specific, and the characteristic histologic lesions of the small-bowel mucosa and remission on a gluten-free diet.

CONCLUSION

An understanding of celiac disease ought to inform everyday clinical practice in all medical disciplines, because this is a common condition with diverse manifestations that can be effectively diagnosed and easily treated for the prevention of both acute and long-term complications. Patients should follow a strictly gluten-free diet for life.

Characteristics and factors related to quality of life in Mexican Mestizo patients with celiac disease

Background

Celiac disease (CD) is a global health problem and its prevalence is underestimated, especially in Latin American populations. Our aim was to evaluate the clinical features, psychological factors, and health-related quality of life (QoL), before and after diagnosis, in a representative sample of adult Mexican Mestizo patients presenting with CD.

Methods

A cross-sectional analysis was conducted on patients seen at two tertiary referral centers in Mexico. QoL before and after CD diagnosis was evaluated using the EuroQoL 5D, the Hospital Anxiety and Depression Scale (HADS), and the disease-specific Celiac Symptom Index (CSI) questionnaires.

Results

We included 80 patients (80% were women, with a mean age of 48.6 ± 14.1 years). The most common symptoms were diarrhea (86%), bloating (77.5%), and abdominal pain (71.3%). Mean symptom duration was 10.33 ± 6.3 years. Fifty-one patients (63.8%) had a previous diagnosis of irritable bowel syndrome (IBS) and 23 (28.8%) had one of functional dyspepsia. Questionnaire respondents rated their health status at 50% before diagnosis (0 = worst imaginable state, 100 = best imaginable state) and there was a significant improvement of 26% after diagnosis. Thirty-nine percent of the patients had a CSI score > 45 and they were the ones that had been previously diagnosed most often with IBS (p = 0.13) or dyspepsia (p = .036).

Conclusions

At the time of diagnosis, Mexican Mestizo patients with CD had poor QoL. Long-standing symptoms and a previous diagnosis of functional disorders were associated with worse QoL. As in other populations, our results support the need for a detailed examination of cost-effective strategies for increasing CD awareness in clinical practice.

Overview of biomarkers for diagnosis and monitoring of celiac disease

Among the adverse reactions caused by wheat, celiac disease (CD) is the longest studied and best-known pathology. The more recently defined non-celiac gluten sensitivity (NCGS) presents with symptoms which are often indistinguishable from CD. Diagnosis of CD is based on serologic, molecular, and bioptic testing. The IgA anti-transglutaminase (tTG) test is considered highly important, as it shows high sensitivity and specificity and its levels correlate to the degree of intestinal damage. Small bowel biopsy can be avoided in symptomatic patients with IgA anti-tTG levels above 10× the manufacturer's cut-off. Recently, tests of anti-deamidated peptides of gliadin (DGP) have replaced classic anti-native gliadin (AGA) tests. DGP assays have a considerably higher diagnostic accuracy than AGA assays, especially in the IgG class, and can replace anti-tTG tests in patients with selective IgA deficiency. The combination of IgG anti-DGP plus IgA anti-tTG assays show greater sensitivity than a single test, with very high specificity. EMA tests have great diagnostic accuracy but are not recommended by all the latest guidelines because they are observer dependent. Biopsy must still be considered the gold standard for CD diagnosis. HLA-DQ genotyping can be used to screen asymptomatic children and in cases of histology/serology disagreement. About half of NCGS patients are DQ2 positive and have IgG AGA. To diagnose NCGS, first CD and wheat allergy must be excluded; then the wheat dependence of symptoms must be verified by a gluten-free diet and subsequent gluten challenge.

Prevalence of celiac disease and celiac autoimmunity in the Toba Native Amerindian community of Argentina

BACKGROUND

Celiac disease (CD) is mostly recognized among subjects with a Caucasian ethnic ancestry. No studies have explored conditions predisposing Amerindians to CD.

OBJECTIVE

To prospectively assess environmental, genetic and serological conditions associated with CD among members of the Toba native population attending a multidisciplinary sanitary mission.

METHODS

An expert nutritionist determined daily gluten intake using an established questionnaire. Gene typing for the human leukocyte antigen (HLA) class II alleles was performed on DNA extracted from peripheral blood (HLA DQ2⁄DQ8 haplotype). Serum antibodies were immunoglobulin (Ig) A tissue transglutaminase (tTG) and the composite deamidated gliadin peptides⁄tTG Screen test. Positive cases were tested for IgA endomysial antibodies.

RESULTS

A total of 144 subjects (55% female) were screened. The estimated mean gluten consumption was 43 g⁄day (range 3 g⁄day to 185 g⁄day). Genetic typing showed that 73 of 144 (50.7%) subjects had alleles associated with CD; 69 (94.5%) of these subjects had alleles for HLA DQ8 and four had DQ2 (5.5%). Four and six subjects had antibody concentrations above the cut-off established by the authors' laboratory (>3 times the upper limit of normal) for IgA tTG and deamidated gliadin peptides⁄tTG screen, respectively. Four of these had concomitant positivity for both assays and endomysial antibodies were positive in three subjects who also presented a predisposing haplotype.

CONCLUSION

The present study was the first to detect CD in Amerindians. The native Toba ethnic population has very high daily gluten consumption and a predisposing genetic background. We detected subjects with persistent CD autoimmunity and, at least, three of them fulfilled serological criteria for CD diagnosis.

Candidate Gene Knockdown in Celiac Disease

RNA interference (RNAi) is a powerful genetic tool that has created new opportunities in cell biology by allowing the specific modulation of gene expression under controlled conditions. Knockdown of genes associated with disease can provide valuable information pertaining to their function and potentially their role in the disease etiology. In the context of celiac disease, it allows us to examine closely the cellular changes that occur when the expression levels of genes of interest are reduced. Utilizing informative assays that demonstrate changes in cell behavior or other measurable endpoints such as cytokine production or migratory phenotypes can further our understanding of the pathogenic mechanisms in this prevalent autoimmune disorder. This chapter outlines protocols for examining the effects of RNAi on candidate genes and subsequent changes to migratory phenotype, transmigration, and adhesion.

Managing coeliac disease in patients with diabetes

The association between coeliac disease and type 1 diabetes has long been established. The combination of genetic susceptibility along with a potential role for gluten in the pathogenesis of autoimmunity makes defining gluten's role in type 1 diabetes extremely important. Evidence supporting the role of a gluten-free diet to improve complications associated with type 1 diabetes is not robust. However there is evidence to support improved growth, bone density and potentially the prevention of additional autoimmune diseases in patients with coeliac disease and type 1 diabetes. The gluten free diet is expensive and challenging to adhere to in people already on a modified diet. Early identification of those who have coeliac disease and would benefit from a gluten-free diet is of utmost importance to prevent complications associated with type 1 diabetes and coeliac disease.

Mucosal molecular pattern of tissue transglutaminase and interferon gamma in suspected seronegative celiac disease at marsh 1 and 0 stages

BACKGROUND/AIM

In celiac disease (CD), there is increased mRNA coding for tissue transglutaminase (tTG) and interferon gamma (IFNα). In seronegative celiac patients, the mucosal immune complexes anti-tTG IgA/tTG are found. We assayed tTG- and IFNα-mRNA in the mucosa of patients with a clinical suspicion of seronegative CD and correlated the values with intraepithelial CD3 lymphocytes (IELs).

MATERIALS AND METHODS

Distal duodenum specimens from 67 patients were retrieved and re-evaluated for immunohistochemically proven CD3 IELs. Five 10 μm sections were used for the extraction and assay of tTG and IFNα coding mRNA levels using reverse transcriptase real-time polymerase chain reaction (RT-PCR). Samples from 15 seropositive CD patients and 15 healthy subjects were used as positive and negative controls. Results were expressed as fold-change.

RESULTS

Our series was divided into three groups based on IEL count: >25 (14 patients: group A), 15-25 (26 patients: group B), and 0-15 (27 patients: Group C). tTG-mRNA levels were (mean ± SD): CD = 9.8 ± 2.6; group A = 10.04 ± 4.7; group B = 4.99 ± 2.3; group C = 2.26 ± 0.8, controls = 1.04 ± 0.2 (CD = group A > group B > group C = controls). IFNα-mRNA levels were: CD = 13.4 ± 3.6; group A = 7.28 ± 3.6; group B = 4.45 ± 2.9; group C = 2.06 ± 1.21, controls = 1.04 ± 0.4.

CONCLUSIONS

Our results suggest that tTG- and IFNγmRNA levels are increased in both seropositive and potential seronegative patients with CD, showing a strong correlation with the CD3 IEL count at stage Marsh 1. An increase in both molecules is found even when IELs are in the range 15-25 (Marsh 0), suggesting the possibility of a "gray zone" inhabited by patients which should be closely followed up in gluten-related disorders.

An unusual cause of constipation in a patient without any underlying disorders

Constipation is the most common digestive complaint in the general population. It is associated with considerable adverse effect on quality of life and substantial economic costs and often has no underlying pathology. Non-Celiac Gluten Sensitivity (NCGS) has been described as a cause of constipation in a few studies. We present a 62-year-old male with long standing constipation without any underlying cause during extensive surveys and not responding to any conservative treatment but significant response with gluten free diet (GFD).

Celiac disease: an immune dysregulation syndrome

Celiac disease is a chronic immune-mediated condition that develops in genetically predisposed individuals. It is characterized by the presence of circulating auto-antibodies in addition to an enteropathy and at times, other extra-intestinal manifestations triggered by exposure to the gliadin fraction of gluten, a family of proteins found in wheat, barley, and rye. There seems to be a rise in reported adverse reactions to gluten, an entity currently termed non-celiac gluten (or perhaps more accurately, wheat) sensitivity, where neither the enteropathy nor the auto-antibodies are present. Celiac disease has protean extra-intestinal manifestations, and an accurate diagnosis should be sought in people suffering from seemingly unrelated complaints, such as fatigue, anorexia, delayed puberty, short stature, decreased bone density, unusual skin rashes, unexplained iron deficiency, and infertility. The presence of an enteropathy, in conjunction with the positive serology, is considered the diagnostic gold standard for making the diagnosis of celiac disease. It is important to stress that the elimination of gluten, even in asymptomatic patients, brings about health benefits, particularly in relation to bone health, as well as a decrease in the incidence of small bowel malignancy, especially lymphoma. Better understanding of the pathophysiology of celiac disease and the molecular mechanisms involved in antigen recognition and processing has provided the impetus for the development of pharmacologic agents that might block the recognition of gluten and its conversion to a toxic antigenic target. Inhibition of tight junction dysregulation could also prevent or minimize the damage triggered by gluten. Work on genetically modified wheat cultivars has progressed, and the possibility of a vaccine to block the immune mediated trigger is being actively investigated. Education and guidance by a knowledgeable nutritionist or registered dietitian can go a long way in minimizing the stress and facilitating the acceptance of the diet and the life-style changes that it represents.

Isotretinoin use and celiac disease: a population-based cross-sectional study

BACKGROUND AND AIM

Isotretinoin, a vitamin A analogue, can promote a pro-inflammatory milieu in the small intestine in response to dietary antigens. We hypothesized that oral isotretinoin exposure would increase the risk of celiac disease (CD).

METHODS

We contacted all 28 pathology departments in Sweden, and through biopsy reports identified 26,739 individuals with CD. We then compared the prevalence of ever using oral isotretinoin to the prevalence in 134,277 matched controls through conditional logistic regression. Data on isotretinoin exposure were obtained from the national Swedish Prescribed Drug Registry. As the only indication for isotretinoin use in Sweden is acne, we also examined its relationship to CD. Data on acne were obtained from the Swedish Patient Registry.

RESULTS

Ninety-three individuals with CD (0.35 %) and 378 matched controls (0.28 %) had a prescription of isotretinoin. This corresponded to an odds ratio (OR) of 1.22 [95 % confidence interval (CI) 0.97-1.54]. Risk estimates were similar in men and women, and when we restricted our data to individuals diagnosed after the start of the Prescribed Drug Registry. Restricting our analyses to individuals diagnosed aged 12-45 years did not influence the risk estimates (OR 1.38, 95 % CI 0.97-1.97). Meanwhile, having a diagnosis of acne was positively associated with CD (OR 1.34, 95 % CI 1.20-1.51).

CONCLUSIONS

This study found no association between isotretinoin use and CD, but a small excess risk of CD in patients with a diagnosis of acne.

The changing clinical profile of celiac disease: a 15-year experience (1998-2012) in an Italian referral center

BACKGROUND

Celiac disease is a multiform, challenging condition characterized by extremely variable features. Our goal was to define clinical, serological and histopathological findings in a large cohort of celiacs diagnosed in a single referral center.

METHODS

From January 1998 to December 2012, 770 patients (599 females, median age 36 years, range 18-78 years) were diagnosed as celiacs at St. Orsola-Malpighi Hospital (Bologna, Italy). The clinical phenotypes were classified as: 1) classical (malabsorption syndrome); 2) non-classical (extraintestinal and/or gastrointestinal symptoms other than diarrhea); 3) subclinical. Serology, duodenal histology, comorbidities, response to gluten-free diet and complications were evaluated.

RESULTS

Disease onset was symptomatic in 610 patients (79%), while 160 celiacs showed a subclinical phenotype. In the symptomatic group the non-classical prevailed over the classical phenotype (66% vs 34%). Diarrhea was found in 27%, while other gastrointestinal manifestations were bloating (20%), aphthous stomatitis (18%), alternating bowel habit (15%), constipation (13%) and gastroesophageal reflux disease (12%). Extraintestinal manifestations included osteopenia/osteoporosis (52%), anemia (34%), cryptogenic hypertransaminasemia (29%) and recurrent miscarriages (12%). Positivity for IgA tissue transglutaminase antibodies was detected in 97%. Villous atrophy was found in 87%, while 13% had minor lesions consistent with potential celiac disease. A large proportion of patients showed autoimmune disorders, i.e. autoimmune thyroiditis (26.3%), dermatitis herpetiformis (4%) and diabetes mellitus type 1 (3%). Complicated celiac disease was very rare.

CONCLUSIONS

Our study demonstrates that the clinical profile of celiac disease changed over time with an increasing rate of non-classical and subclinical phenotypes.

The presence of anti-endomysial antibodies and the level of anti-tissue transglutaminases can be used to diagnose adult coeliac disease without duodenal biopsy

BACKGROUND

The new ESPGHAN guidelines for diagnosis of paediatric coeliac disease suggest to avoid biopsy in genetically pre-disposed and symptomatic individuals with positive anti-endomysial antibodies (EMA) and anti-tissue transglutaminases (a-tTG). However, duodenal biopsy remains the gold standard in adult coeliac disease.

AIMS

To establish the cut-off values of a-tTG, which would: predict the presence of duodenal histology (Marsh ≥2) diagnostic for coeliac disease; and predict the presence of villous atrophy (Marsh 3) in adults.

METHODS

We performed an observational prospective study including all consecutive adult patients with suspected coeliac disease. All subjects were tested for EMA and a-tTG. Coeliac disease diagnosis was made in presence of Marsh ≥2, a-tTG >7 U/mL and positive EMA. A ROC curve was constructed to establish the best specificity cut-off of a-tTG levels, which would predict the presence of Marsh ≥2 and Marsh 3 at histology.

RESULTS

The study included 310 patients with positive antibodies. Histology showed Marsh 1 in 8.7%, Marsh 2 in 3.5%, Marsh 3 in 87.7%. The best cut-off value of a-tTG for predicting Marsh ≥2 was 45 U/mL (sensitivity 70%; specificity 100%; PPV 100%; NPV 24.1%); the best cut-off for predicting villous atrophy was 62.4 U/mL (sensitivity 69%, specificity 100%; PPV 100%; NPV 31%).

CONCLUSIONS

The diagnosis of coeliac disease can be reached without histology in adult patients with positive EMA and a-tTG levels >45 U/mL. An a-tTG level >62.4 was diagnostic for villous atrophy. These results could contribute to improving the diagnosis of coeliac disease by allowing for a significant reduction in diagnosis-related costs.

Investigation into celiac disease in Indian patients with portal hypertension

BACKGROUND

There is limited data on celiac disease in patients with cryptogenic cirrhosis or idiopathic noncirrhotic intrahepatic portal hypertension (NCIPH). Our objective was to evaluate for celiac disease in patients with portal hypertension in India.

METHODS

Consecutive patients with portal hypertension having cryptogenic chronic liver disease (cases) and hepatitis B- or C-related cirrhosis (controls) were prospectively enrolled. We studied tissue transglutaminase (tTG) antibody and duodenal histology in study patients.

RESULT

Sixty-one cases (including 14 NCIPH patients) and 59 controls were enrolled. Celiac disease was noted in six cases (including two NCIPH patients) as compared to none in controls. In a significant proportion of the remaining study subjects, duodenal biopsy showed villous atrophy, crypt hyperplasia, and lamina propria inflammation, not accompanied by raised intraepithelial lymphocytes (IELs); this was seen more commonly in cases as compared to controls. An unexpectedly high rate of tTG antibody positivity was seen in study subjects (66 %) of cases as compared to 29 % in controls (p-value < 0.001), which could indicate false-positive test result.

CONCLUSION

In this study, 10 % of patients with unexplained portal hypertension (cryptogenic chronic liver disease) had associated celiac disease. In addition, an unexplained enteropathy was seen in a significant proportion of study patients, more so in patients with cryptogenic chronic liver disease. This finding warrants further investigation.

Systematic review with meta-analysis: associations between coeliac disease and type 1 diabetes

BACKGROUND

In the past decade, a number of population-based studies have examined the prevalence of coeliac disease in individuals with type 1 diabetes but prevalences have differed considerably.

AIM

To examine the prevalence of coeliac disease in individuals with type 1 diabetes.

METHODS

A systematic review of English-language articles published in PubMed Medline between 2000 and May 2014. Search terms included 'celiac disease' or 'coeliac disease' and 'diabetes mellitus'. Studies were selected with at least 100 individuals with type 1 diabetes being screened for coeliac disease where the coeliac diagnosis was later confirmed through small intestinal biopsy. Data synthesis used random-effects inverse variance-weighted models, and metaregression was used to examine heterogeneity in subgroups.

RESULTS

A pooled analysis, based on 26,605 patients with type 1 diabetes, found a prevalence of biopsy-confirmed coeliac disease of 6.0% (95% CI = 5.0-6.9%). Heterogeneity was large (I(2) = 93.2%). The prevalence was lower in adults with type 1 diabetes (2.7%), and in mixed populations with both children and adults with type 1 diabetes (4.7%) than in children (6.2%) with type 1 diabetes (P < 0.001). Additional subgroup analyses could not explain the large variation in coeliac disease prevalence between studies.

CONCLUSION

More than one in twenty patients with type 1 diabetes have biopsy-verified coeliac disease. This prevalence is high enough to motivate screening for coeliac disease among patients with type 1 diabetes.

Diagnosing coeliac disease and the potential for serological markers

The diagnosis of coeliac disease has advanced in the past decade owing to increased clinical awareness and improved tests. Coeliac disease is now regarded as a common disease presenting at any age with a broad spectrum of symptoms. Previous guidelines on diagnosis relied on the histological analysis of duodenal biopsy samples. However, contemporary antibody analysis is a diagnostic tool with a comparatively high accuracy that has reduced reliance on performing biopsies. Furthermore, determination of HLA-based genetic susceptibility to coeliac disease has become routine. European and North American guidelines utilize symptoms, coeliac antibodies (primarily tissue transglutaminase 2 IgA and endomysial IgA antibodies), HLA determination and histological analysis of biopsy tissue for diagnosis. Some guidelines conclude that the diagnostic accuracy of tissue transglutaminase 2 IgA antibodies is sufficient to omit duodenal biopsies in selected children with very high antibody levels, in the presence of clear symptom response as well as a positive endomysial antibody test and confirmation of genetic susceptibility. This Review discusses if such a strategy is appropriate for children and adults in all populations. The performance characteristics of antibody tests (particularly of the tissue transglutaminase 2 IgA test) including quality control and characterisation of the population in whom testing is performed are also discussed.

Gut microbes and adverse food reactions: Focus on gluten related disorders

Immediately following birth, the gastrointestinal tract is colonized with a complex community of bacteria, which helps shape the immune system. Under conditions of health, the immune system is able to differentiate between innocuous antigens, including food protein and commensals, and harmful antigens such as pathogens. However, patients with celiac disease (CD) develop an intolerance to gluten proteins which results in a pro-inflammatory T-cell mediated immune response with production of anti-gluten and anti-tissue transglutaminase antibodies. This adaptive immune response, in conjunction with activation of innate inflammatory cells, lead to destruction of the small intestinal mucosa. Overall 30% of the global population has genetic risk to develop CD. However, only a small proportion develop CD, suggesting that additional environmental factors must play a role in disease pathogenesis. Alterations in small intestinal microbial composition have recently been associated with active CD, indicating a possible role for the microbiota in CD. However, studies demonstrating causality are lacking. This review will highlight the recent data on the potential role of the microbiota in CD pathogenesis, the potential mechanisms, and discuss future research directions.

Potential blood-based markers of celiac disease

Background

Blood-based diagnostics has the potential to simplify the process of diagnosing celiac disease (CD). Although high levels of autoantibodies against tissue transglutaminase (anti-TG2) are strongly indicative of active CD, several other scenarios involve a need for additional blood-based CD markers.

Methods

We investigated the levels of messenger RNA (mRNA) in whole blood (n = 49) and protein in plasma (n = 22) from cases with active CD (n = 20), with confirmed CD and normalized histology (n = 15), and without a CD diagnosis (n = 14). Group differences were analyzed using Kruskal-Wallis one-way analysis of variance by ranks. We also investigated correlations between levels of potential markers, histopathology according to the modified Marsh scale, and CD risk gradient based on HLA type, using Spearman rank correlation. The relation between HLA-DQ2 gene dose effect and the expression levels of selected blood-based markers was investigated using the Mann–Whitney U test. Finally, the diagnostic performance of anti-TG2, potential blood-based CD markers, and logistic regression models of combined markers was evaluated using receiver operating characteristic (ROC) curve analysis.

Results

CXCL11 protein levels and TNFRSF9 and TNFSF13B mRNA levels were identified as potential CD markers. These are all affected by or involved in the regulation of the NF-κB complex. CXCL11 protein levels and IL21 and IL15 mRNA levels were correlated with histopathology according to the modified Marsh scale, as were the established CD markers. HLA genotype risk and HLA-DQ2 gene dose effect did not show any significant relations with either the potential CD markers or the established CD markers. ROC curve analysis revealed a slight, non-significant increase in the area under the curve for the combined use of anti-TG2 and different constellations of potential blood-based CD markers compared to anti-TG2 alone.

Conclusions

The CD markers identified in this study further emphasize the significance of components related to NF-κB regulation in relation to CD. However, the relevance of CXCL11, TNFSF13B, TNFRSF9, and other NF-κB interacting proteins recognized by pathway analysis, needs to be further investigated in relation to diagnosis and monitoring of CD.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-230X-14-176) contains supplementary material, which is available to authorized users.