Anti-tissue transglutaminase antibodies in patients with abnormal liver tests: is it always coeliac disease?

Patterns of IgA Autoantibody Generation, Inflammatory Responses and Extracellular Matrix Metabolism in Patients with Alcohol Use Disorder

Recent data have emphasized the role of inflammation and intestinal immunoglobulin A (IgA) responses in the pathogenesis of alcoholic liver disease (ALD). In order to further explore such associations, we compared IgA titers against antigens targeted to ethanol metabolites and tissue transglutaminase with pro- and anti-inflammatory mediators of inflammation, markers of liver status, transferrin protein desialylation and extracellular matrix metabolism in alcohol-dependent patients with or without liver disease and in healthy controls. Serum IgAs against protein adducts with acetaldehyde (HbAch-IgA), the first metabolite of ethanol, and tissue transglutaminase (tTG-IgA), desialylated transferrin (CDT), pro- and anti-inflammatory cytokines, markers of liver status (GT, ALP) and extracellular matrix metabolism (PIIINP, PINP, hyaluronic acid, ICTP and CTx) were measured in alcohol-dependent patients with (n = 83) or without (n = 105) liver disease and 88 healthy controls representing either moderate drinkers or abstainers. In ALD patients, both tTG-IgA and HbAch-IgA titers were significantly higher than those in the alcoholics without liver disease (p < 0.0005 for tTG-IgA, p = 0.006 for Hb-Ach-IgA) or in healthy controls (p < 0.0005 for both comparisons). The HbAch-IgA levels in the alcoholics without liver disease also exceeded those found in healthy controls (p = 0.0008). In ROC analyses, anti-tTG-antibodies showed an excellent discriminative value in differentiating between ALD patients and healthy controls (AUC = 0.95, p < 0.0005). Significant correlations emerged between tTG-IgAs and HbAch-IgAs (rs = 0.462, p < 0.0005), CDT (rs = 0.413, p < 0.0001), GT (rs = 0.487, p < 0.0001), alkaline phosphatase (rs = 0.466, p < 0.0001), serum markers of fibrogenesis: PIIINP (rs = 0.634, p < 0.0001), hyaluronic acid (rs = 0.575, p < 0.0001), ICTP (rs = 0.482, p < 0.0001), pro-inflammatory cytokines IL-6 (rs = 0.581, p < 0.0001), IL-8 (rs = 0.535, p < 0.0001) and TNF-α (rs = 0.591, p < 0.0001), whereas significant inverse correlations were observed with serum TGF-β (rs = -0.366, p < 0.0001) and CTx, a marker of collagen degradation (rs = -0.495, p < 0.0001). The data indicate that the induction of IgA immune responses toward ethanol metabolites and tissue transglutaminaseis a characteristic feature of patients with AUD and coincides with the activation of inflammation, extracellular matrix remodeling and the generation of aberrantly glycosylated proteins. These processes appear to work in concert in the sequence of events leading from heavy drinking to ALD.

[Elevated liver enzymes: A diagnostic challenge]

The differential diagnosis of elevated liver enzymes is a key aspect of hepatology and a diagnostic challenge for many. Elevated liver enzymes may mostly indicate liver damage but also physiologic elevations or extrahepatic causes are possible. A rational approach to the differential diagnosis of elevated liver enzymes is necessary to avoid overdiagnosis while not missing rare causes of liver disease.

Fatty liver and celiac disease: Why worry?

Celiac disease (CD) is a chronic inflammatory intestinal disorder mediated by the ingestion of gluten in genetically susceptible individuals. Liver involvement in CD has been widely described, and active screening for CD is recommended in patients with liver diseases, particularly in those with autoimmune disorders, fatty liver in the absence of metabolic syndrome, noncirrhotic intrahepatic portal hypertension, cryptogenic cirrhosis, and in the context of liver transplantation. Non-alcoholic fatty liver disease is estimated to affect approximately 25% of the world’s adult population and is the world’s leading cause of chronic liver disease. In view of both diseases’ global significance, and to their correlation, this study reviews the available literature on fatty liver and CD and verifies particularities of the clinical setting.

Prevalence of celiac disease in patients with liver diseases: a systematic review and meta-analyses

OBJECTIVES

A subset of patients with celiac disease (CeD) have liver involvement in the form of hypertransaminasemia, liver cirrhosis and autoimmune hepatitis. We conducted a systematic review with meta-analyses to determine pooled prevalence of CeD in patients with cryptogenic cirrhosis, all-cause cirrhosis, cryptogenic hypertransaminasemia, and all-cause hypertransaminasemia.

METHODS

We searched PubMed and EMBASE up to January 2022. Cross-sectional, case-control and prospective cohort studies performing serological tests and/or intestinal biopsy for CeD on patients with cryptogenic cirrhosis, all-cause cirrhosis, cryptogenic hypertransaminasemia and all-cause hypertransaminasemia were included, to calculate pooled estimates of seroprevalence and prevalence of biopsy-confirmed CeD in these four groups.

RESULTS

Of 6,871 articles screened, 20 articles were included finally in three meta-analyses for cryptogenic cirrhosis, all-cause cirrhosis and cryptogenic hypertransaminasemia. For the all-cause hypertransaminasemia group, a qualitative review of four studies was done instead of a meta-analysis, due to significant differences in studies. The pooled prevalence (95%CI) of biopsy-confirmed CeD, in cryptogenic cirrhosis was 4.6%(2.2-7.5%) while pooled prevalence of biopsy-confirmed CeD in all-cause cirrhosis was 0.8%(0-3.4%). Pooled prevalence of biopsy-confirmed CeD in cryptogenic hypertransaminasemia was 5.7%(3.2-8.8%).

CONCLUSIONS

Nearly one in 20 patients each with cryptogenic cirrhosis and cryptogenic hypertransaminasemia have CeD, hence they should both be considered high-risk groups for CeD. While prevalence of CeD in all-cause cirrhosis is similar to that in general population, it may be worth screening them for CeD as liver pathology has potential for reversal in them.

Bi-directional Relationship Between Celiac Disease and Liver Chemistries: A Systematic Review and Meta-Analysis

AIMS

Previous studies have reported conflicting results regarding prevalence of elevated LC (2-70%) in celiac disease (CD). This systematic review and meta-analysis assessed the prevalence of elevated LC at time of CD diagnosis and associated response to GFD. We also report the prevalence of CD in patients with unexplained elevation of LC.

METHODS

Studies assessing LC (aspartate aminotransferase [AST] and alanine aminotransferase [ALT]) in CD patients were eligible. Studies with < 50 cases or in pediatric populations were excluded.

RESULTS

In total, 20 studies assessing prevalence of elevated LC in 4,265 participants with newly diagnosed CD (mean age = 35.6 ± 6.5 years, 69.8% female) were included. Pooled prevalence of elevated LC was 18.7% (95% CI 13.8-24.8; I2 = 95%). Normalization of elevated LC was seen in 83.1% (95% CI 73.4-89.7; I2 = 79%, 11 studies) of patients after GFD. On meta-regression, age at CD diagnosis, gender, and Marsh grading were not associated with elevated LC. Among 979 participants (7 studies) with unexplained elevation of LC, pooled seroprevalence and biopsy-proven CD was 6.4% (95% CI 2.9-10.3, I2 = 71%) and 4.5% (95% CI 2.6-7.7, I2 = 67%), respectively.

CONCLUSION

Elevated LC are seen in approximately one-fifth of patients at CD diagnosis with majority normalizing after GFD. Age, gender, and degree of intestinal damage are not predictive of elevated LC. In the appropriate clinical scenario, liver tests should be serially monitored in CD reserving workup for additional causes after a trial of GFD. Patients with unexplained elevation of liver tests should be screened for celiac disease.

Activated gut-homing CD8+ T cells for coeliac disease diagnosis on a gluten-free diet

BACKGROUND

The diagnosis of coeliac disease (CD) in individuals that have started a gluten-free diet (GFD) without an adequate previous diagnostic work-out is a challenge. Several immunological assays such as IFN-γ ELISPOT have been developed to avoid the need of prolonged gluten challenge to induce the intestinal damage. We aimed to evaluate the diagnostic accuracy of activated gut-homing CD8⁺ and TCRγδ⁺ T cells in blood after a 3-day gluten challenge and to compare it with the performance of IFN-γ ELISPOT in a HLA-DQ2.5 subsample.

METHODS

A total of 22 CD patients and 48 non-CD subjects, all of them following a GFD, underwent a 3-day 10-g gluten challenge. The percentage of two T cell subsets (CD8⁺ CD103⁺ β7^hi CD38⁺/total CD8⁺ and TCRγδ⁺ CD103⁺ β7^hi CD38⁺/total TCRγδ⁺) in fresh peripheral blood drawn baseline and 6 days after the challenge was determined by flow cytometry. IFN-γ ELISPOT assays were also performed in HLA-DQ2.5 participants. ROC curve analysis was used to assess the diagnostic performance of the CD8⁺ T cell response and IFN-γ ELISPOT.

RESULTS

Significant differences between the percentage of the two studied subsets of CD8⁺ and TCRγδ⁺ cells at days 0 and 6 were found only when considering CD patients (p < 10^-3 vs. non-CD subjects). Measuring activated CD8⁺ T cells provided accurate CD diagnosis with 95% specificity and 97% sensitivity, offering similar results than IFN-γ ELISPOT.

CONCLUSIONS

The results provide a highly accurate blood test for CD diagnosis in patients on a GFD of easy implementation in daily clinical practice.

Alternative Etiologies of Liver Disease in Children With Suspected NAFLD

OBJECTIVES

To determine the prevalence of alternative causes of liver disease in a cohort of youth with overweight and obesity undergoing evaluation for suspected nonalcoholic fatty liver disease (NAFLD).

METHODS

Multicenter, retrospective cohort study of patients aged ≤18 years with overweight and obesity and evidence of elevated serum aminotransferases and/or hepatic steatosis on imaging, referred for suspected NAFLD to Cincinnati Children's Hospital Medical Center (2009-2017) or Yale New Haven Children's Hospital (2012-2017). Testing was performed to exclude the following: autoimmune hepatitis (AIH), Wilson disease, viral hepatitis (B and C), thyroid dysfunction, celiac disease, α-1 antitrypsin deficiency, and hemochromatosis.

RESULTS

A total of 900 children with overweight and obesity (63% boys, 26% Hispanic ethnicity) were referred, with a median age of 13 years (range: 2-18). Most had severe obesity (n = 666; 76%) with a median BMI z score of 2.45 (interquartile range [IQR]: 2.2-2.7). Median alanine aminotransferase level at presentation was 64 U/L (IQR: 42-95). A clinically indicated liver biopsy was performed in 358 children (40%) at a median of 6 months (IQR: 1-14) post initial visit; of those, 46% had confirmed nonalcoholic steatohepatitis. Positive autoantibodies were observed in 13% of the cohort, but none met criteria for AIH. Only 19 (2%) were found to have other causes of liver disease, with no cases of viral hepatitis or Wilson disease detected.

CONCLUSIONS

In a large, multicenter cohort, the vast majority of children with overweight and obesity with presumed or confirmed NAFLD tested negative for other causes of liver disease. In contrast to a previous pediatric report, no patient was diagnosed with AIH.

Patients with celiac disease are at high risk of developing metabolic syndrome and fatty liver

Background/Aims

Gluten-free diet has an excess of fats and simple sugars and puts patients with celiac disease at risk of metabolic complications including metabolic syndrome and fatty liver. We assessed prevalence of metabolic syndrome and fatty liver in two cohorts of celiac disease.

Methods

Study was done in 2 groups. In group 1, 54 treatment naïve patients with celiac disease were recruited. Of them, 44 returned after 1-year of gluten-free diet and were reassessed. In group 2, 130 celiac disease patients on gluten-free diet for ≥1 year were recruited. All patients were assessed for anthropometric and metabolic parameters and fatty liver. Metabolic syndrome was defined as per consensus definition for Asian Indians. Fatty liver was defined as controlled attenuation parameter value >263 decibels by FibroScan.

Results

In group 1, of 44 treatment naïve patients with celiac disease, metabolic syndrome was present in 5 patients (11.4%) at baseline and 9 (18.2%) after 1 year of gluten-free diet. Patients having fatty liver increased from 6 patients (14.3%) at baseline to 13 (29.5%) after 1year of gluten-free diet (P=0.002). In group 2, of 130 patients with celiac disease on gluten-free diet for a median duration of 4 years, 30 out of 114 (26.3%) and 30 out of 130 patients (23%) had metabolic syndrome and fatty liver, respectively.

Conclusions

Patients with celiac disease are at high risk of developing metabolic syndrome and fatty liver, which increases further with gluten-free diet. These patients should be assessed for nutritional and metabolic features and counseled about balanced diet and physical activity regularly.

Discordance Between Serology and Histology for Celiac Disease in a Cohort with Coexisting Liver Disorders

Background

The liver and celiac disease (CeD) share a complex relationship. While in some patients, isolated hypertransaminasemia is the only manifestation of CeD, liver diseases (LD) may also be associated with the presence of isolated tissue transglutaminase antibodies IgA (tTG IgA) without histologic evidence of CeD.

Aims

To examine the yield of tTG IgA testing (a) in the workup for chronic liver disease (CLD) or cytolysis and (b) to identify biopsy-confirmed CeD (BxCeD) among patients with concomitant LD.

Methods

Retrospective study including two cohorts. Cohort 1 represented 444 consecutive individuals without known CeD for which liver specialists requested tTG IgA. Incidence of positive tTG and BxCeD was evaluated. Cohort 2 included 212 consecutive individuals with positive tTG IgA and subsequent duodenal biopsies. The frequency and clinical characteristics of individuals without BxCeD were examined, with and without concurrent LD.

Results

The rate of first time positive tTG IgA among the tests requested by a liver specialist (cohort 1) was 2.0% (n = 9). However, 33.0% (n = 3) of these patients did not have BxCeD. Cohort 2 included 33 individuals with coexisting LD, of which 42.4% did not have BxCeD, compared with 16.2% of the patients without LD (P < 0.001). The majority of the patients without BxCeD (65.1%) showed an increase < 3 times upper limit of normal of tTG IgA.

Conclusions

Although there is clinical value in testing for CeD in the context of LD, there could be a high rate of positive CeD serology unaccompanied by histologic signs in patients with coexisting LD.

Increased risk of nonalcoholic fatty liver disease in patients with coeliac disease on a gluten-free diet: beyond traditional metabolic factors

BACKGROUND

A gluten-free diet (GFD) is known to be associated with altered macronutrient intake and metabolic syndrome. Nonalcoholic fatty liver disease (NAFLD) is the hepatic hallmark of metabolic syndrome. The risk of NAFLD in patients with coeliac disease (CD) adhering to a GFD remains to be fully investigated; in particular, data from real-life clinical settings are lacking.

AIM

To assess the prevalence and relative risk of NAFLD in CD patients treated with a GFD.

METHODS

Case-control study, with prospective enrolment of CD outpatients following a GFD and controls. Patients were matched for demographic characteristics (age and gender) and metabolic risk factors (overweight, diabetes mellitus, total cholesterol, and triglycerides) using a 1:1 ratio. NAFLD was diagnosed according to the European Association for the Study of the Liver criteria.

RESULTS

202 CD patients and 202 controls were compared. The raw prevalence of NAFLD was 34.7% and 21.8% in the CD and control group, respectively (P = 0.006). Binary logistic regression confirmed an increased risk of NAFLD in the CD group (adjusted odds ratio = 2.90, 95% confidence interval: 1.64-5.15, P < 0.001). Additionally, the relative risk for NAFLD was notably higher in non-overweight CD patients (adjusted odds ratio = 5.71, 95% confidence interval: 2.30-14.19, P < 0.001).

CONCLUSIONS

More than one-third of CD patients adhering to a GFD had concurrent NAFLD, accounting for a three-fold increased risk compared to the general population. Dietary advice provided using a patient-tailored approach should assist CD patients with NAFLD in achieving an appropriate nutritional intake whilst reducing the risk of long-term liver-related events.

Clinicopathological and immunological characteristics and outcome of concomitant coeliac disease and non-alcoholic fatty liver disease in adults: a large prospective longitudinal study

Objective

Concomitant non-alcoholic fatty liver disease (NAFLD) and coeliac disease (CD) have not been adequately studied. This study investigated the frequency of CD among NAFLD patients and the clinicopathological and immunological patterns and outcome of concomitant NAFLD and CD.

Design

This prospective longitudinal study screened patients with NAFLD for CD (tissue transglutaminase antibodies (TTGA); anti-TTGA and antiendomysial antibodies (EMA)). Patients with concomitant NAFLD and CD and patients with either NAFLD or CD were enrolled and followed. Duodenal biopsy, transient elastography, tumour necrosis factor (TNF)-alpha, transforming growth factor-beta, interleukins (ILs) 1, 6, 10, 15 and 17, folic acid and vitamins B12 and D were performed at baseline and 1 year after gluten-free diet (GFD).

Results

CD was confirmed in 7.2% of patients with NAFLD. Refractory anaemia and nutritional deficiencies were frequent in patients with concomitant NAFLD and CD who had advanced intestinal and hepatic lesions, higher levels of TNF-α, IL-15 and IL-17 compared with patients with CD and NAFLD. Patients concomittant CD and NAFLD showed clinical response to GFD, but intestinal histological improvement was suboptimal. Combining EMA-IgA or anti-TTGA with either IL-15 or IL-17 enhances the prognostic performance of both tests in predicting histological response to GFD.

Conclusion

Concomitant NAFLD and CD is not uncommon. Recurrent abdominal symptoms, refractory anaemia, nutritional deficiencies in patients with NAFLD warrant screening for CD. The study has important clinical implications since failure in diagnosing CD in patients with NAFLD patients results in marked intestinal and hepatic damage and suboptimal response to GFD that can be alleviated by early diagnosis and initiation of GFD.

Elevated Liver Enzymes in Asymptomatic Patients - What Should I Do?

Elevated liver enzymes are a common scenario encountered by physicians in clinical practice. For many physicians, however, evaluation of such a problem in patients presenting with no symptoms can be challenging. Evidence supporting a standardized approach to evaluation is lacking. Although alterations of liver enzymes could be a normal physiological phenomenon in certain cases, it may also reflect potential liver injury in others, necessitating its further assessment and management. In this article, we provide a guide to primary care clinicians to interpret abnormal elevation of liver enzymes in asymptomatic patients using a step-wise algorithm. Adopting a schematic approach that classifies enzyme alterations on the basis of pattern (hepatocellular, cholestatic and isolated hyperbilirubinemia), we review an approach to abnormal alteration of liver enzymes within each section, the most common causes of enzyme alteration, and suggest initial investigations.

Chronic Hepatitis Due to Gluten Enteropathy - a Case Report

BACKGROUND

Celiac disease is an immune-mediated enteropathy precipitated by exposure to dietary gluten in genetically predisposed individuals.

CASE DESCRIPTION

A 45-year-old Caucasian woman presented with severe iron-deficient anemia and mild elevation of liver enzymes. Upper endoscopy was done in the context of evaluation of anemia, which revealed reduced duodenal folds and mosaic pattern of the mucosa, but also grade II esophageal varices and portal hypertensive gastropathy. Duodenal biopsy showed total villous atrophy, diffuse mainly lymphocytic infiltrate, presence of intra-epithelial lymphocytes. Serology test confirmed celiac disease by the typical pattern of high titer positive IgA and IgG antibodies to tissue transglutaminase. Liver biopsy was performed for staging and etiological evaluation, because laboratory screening ruled out common viral, metabolic and autoimmune liver disease. Liver morphology was consistent with chronic hepatitis without findings for extensive fibrosis. Our patient had poor dietary compliance, so we failed to established improvement of liver enzymes and resolution of anemia during follow-up.

CONCLUSIONS

We would like to stress on the diverse clinical manifestations of celiac disease and the importance of serologic screening with antibodies to tissue transglutaminase in differential diagnosis of chronic liver disease.

To screen or not to screen? Celiac antibodies in liver diseases

Celiac disease (CD) is a systemic immune-mediated disorder triggered by dietary gluten in genetically predisposed individuals. The typical symptoms are anemia, diarrhea, fatigue, weight loss, and abdominal pain. CD has been reported in patients with primary sclerosing cholangitis, primary biliary cholangitis, autoimmune hepatitis, aminotransferase elevations, nonalcoholic fatty liver disease, hepatitis B, hepatitis C, portal hypertension and liver cirrhosis. We evaluate recommendations for active screening for CD in patients with liver diseases, and the effect of a gluten-free diet in these different settings. Active screening for CD is recommended in patients with liver diseases, particularly in those with autoimmune disorders, steatosis in the absence of metabolic syndrome, noncirrhotic intrahepatic portal hypertension, cryptogenic cirrhosis, and in the context of liver transplantation. In hepatitis C, diagnosis of CD can be important as a relative contraindication to interferon use. Gluten-free diet ameliorates the symptoms associated with CD; however, the associated liver disease may improve, remain the same, or progress.

Relevance, pathogenesis and clinical implications of thyroid disorders in children with celiac disease

Celiac disease is a frequent chronic inflammatory small bowel disease which may present itself with associated autoimmune comorbidities. Among these comorbidities, thyroid disorders show a significant prevalence; even in the pediatric population. However, the exact epidemiology and clinical significance of such alterations are yet to be fully elucidated. The most updated guidelines do not currently offer any specific support. Focusing on the pediatric population, we will review the recent available literature that we believe might be helpful in advancing the clinician's knowledge-base regarding this issue. We also discuss which, to our knowledge, are the key pathophysiologic concepts behind the association between these two entities. Finally, we offer our own clinical perspective, recommending routine laboratory thyroid screening, possibly followed by an echographic thyroid evaluation as we believe such an approach to be appropriate when caring for children with celiac disease.

Liver involvement in pediatric celiac disease

Celiac disease (CD) is an intestinal inflammatory disease that manifests in genetically susceptible individuals when exposed to dietary gluten. It is a common chronic disorder, with a prevalence of 1% in Europe and North America. Although the disease primarily affects the gut, the clinical spectrum of CD is remarkably varied, and the disease can affect many extraintestinal organs and systems, including the liver. The hepatic dysfunction presenting in CD ranges from asymptomatic liver enzyme elevations or nonspecific reactive hepatitis (cryptogenic liver disorders), to chronic liver disease. In this article, we review the clinical presentations and possible mechanisms of CD-related liver injury to identify strategies for the diagnosis and treatment of these disorders in childhood.

Transglutaminse 2 and EGGL, the protein cross-link formed by transglutaminse 2, as therapeutic targets for disabilities of old age

Aging of the extracellular matrix (ECM), the protein matrix that surrounds and penetrates the tissues and binds the body together, contributes significantly to functional aging of tissues. ECM proteins become increasingly cross-linked with age, and this cross-linking is probably important in the decline of the ECM's function. This article reviews the role of ε-(γ-glutamyl)-lysine (EGGL), a cross-link formed by transglutaminase enzymes, and particularly the widely expressed isozyme transglutaminase 2 (TG2), in the aging ECM. There is little direct data on EGGL accumulation with age, and no direct evidence of a role of EGGL in the aging of the ECM with pathology. However, several lines of circumstantial evidence suggest that EGGL accumulates with age, and its association with pathology suggests that this might reflect degradation of ECM function. TG activity increases with age in many circumstances. ECM protein turnover is such that some EGGL made by TG is likely to remain in place for years, if not decades, in healthy tissue, and both EGGL and TG levels are enhanced by age-related diseases. If further research shows EGGL does accumulate with age, removing it could be of therapeutic benefit. Also reviewed is the blockade of TG and active removal of EGGL as therapeutic strategies, with the conclusion that both have promise. EGGL removal may have benefit for acute fibrotic diseases, such as tendinopathy, and for treating generalized decline in ECM function with old age. Extracellular TG2 and EGGL are therefore therapeutic targets both for specific and more generalized diseases of aging.

The role of celiac disease in severity of liver disorders and effect of a gluten free diet on diseases improvement

CONTEXT

Celiac disease (CD) is defined as a permanent intolerance to ingested gluten. The intolerance to gluten results in immune-mediated damage of small intestine mucosa manifested by villous atrophy and crypt hyperplasia. These abnormalities resolve with initiationa gluten-free diet.

EVIDENCE ACQUISITION

PubMed, Ovid, and Google were searched for full text articles published between 1963 and 2012. The associated keywords were used, and papers described particularly the impact of celiac disease on severity of liver disorder were identified.

RESULTS

Recently evidence has emerged revealingthat celiac disease not only is associated with small intestine abnormalities and malabsorption, but is also a multisystem disorder affecting other systems outside gastrointestinal tract, including musculo-skeletal, cardiovascular and nervous systems. Some correlations have been assumed between celiac and liver diseases. In particular, celiac disease is associated with changes in liver biochemistry and linked to alter the prognosis of other disorders. This review will concentrate on the effect of celiac disease and gluten-free diets on the severity of liver disorders.

CONCLUSIONS

Although GFD effect on the progression of CD associated liver diseases is not well defined, it seems that GFD improves liver function tests in patients with a hypertransaminasemia.

Prevalence of coeliac disease in patients with non-alcoholic fatty liver disease

BACKGROUND AND STUDY AIMS

Coeliac disease (CD) may be associated with several liver disorders including primary biliary cirrhosis, primary sclerosing cholangitis and autoimmune hepatitis. Furthermore preliminary data suggest a causative role of CD in steatosis and steatohepatitis. The aim of present study was to determine the prevalence of CD in a series of patients with non-alcoholic fatty liver disease (NAFLD).

PATIENTS AND METHODS

In a cross sectional study (2008-2010), 403 consecutive NAFLD patients (127 female and 276 male) referred to GI clinics of the Zahedan University of Medical Sciences were included. IgA anti-tissue transglutaminase (Anti-tTG) was used for screening of coeliac disease. In the patients with a positive serologic test, duodenal biopsies were taken to confirm the diagnosis.

RESULTS

The mean±SD of the age and BMI of patients were 37.4±12.4years and 28.3±4.15kg/m(2) respectively. BMIs lower than 25kg/m(2) were found in 58 subjects (14.5%). Furthermore diabetes mellitus and hyperlipidaemia were diagnosed in 48 (11.9%) and 84 (20.8%) individuals respectively. Positive Anti-tTGs were found in 14/403 (3.4%) and 13/403 (3.2%, 95% CI 1.5-4.9) had coeliac disease according to the modified Marsh classification; 8 had type I, 3 type II, 1 type IIIA and 1 type IIIB lesions.

CONCLUSION

According to our data, prevalence of CD in the subjects with NAFLD is higher than the rates reported in the general population. Therefore screening for CD in selected cases of NAFLD may be appropriate.

Celiac disease and autoimmune-associated conditions

Celiac disease (CD) is frequently accompanied by a variety of extradigestive manifestations, thus making it a systemic disease rather than a disease limited to the gastrointestinal tract. This is primarily explained by the fact that CD belongs to the group of autoimmune diseases. The only one with a known etiology is related to a permanent intolerance to gluten. Remarkable breakthroughs have been achieved in the last decades, due to a greater interest in the diagnosis of atypical and asymptomatic patients, which are more frequent in adults. The known presence of several associated diseases provides guidance in the search of oligosymptomatic cases as well as studies performed in relatives of patients with CD. The causes for the onset and manifestation of associated diseases are diverse; some share a similar genetic base, like type 1 diabetes mellitus (T1D); others share pathogenic mechanisms, and yet, others are of unknown nature. General practitioners and other specialists must remember that CD may debut with extraintestinal manifestations, and associated illnesses may appear both at the time of diagnosis and throughout the evolution of the disease. The implementation of a gluten-free diet (GFD) improves the overall clinical course and influences the evolution of the associated diseases. In some cases, such as iron deficiency anemia, the GFD contributes to its disappearance. In other disorders, like T1D, this allows a better control of the disease. In several other complications and/or associated diseases, an adequate adherence to a GFD may slow down their evolution, especially if implemented during an early stage.

Quality not quantity for transglutaminase antibody 2: the performance of an endomysial and tissue transglutaminase test in screening coeliac disease remains stable over time

National Institute of Clinical Excellence (NICE) and European Society for Paediatric Gastroenterology, Hepatology and Nutrition (ESPGHAN) guidance for the diagnosis of coeliac disease has been published. However, there is some controversy regarding the advice on the use of stratifying levels of immunoglobulin (IgA) tissue transglutaminase antibody (TG2) test positivity in the absence of test standardization and the vagueness of the indication to test equivocal samples. Using repeat service audit, we demonstrate that a combination of TG2 followed by IgA endomysial antibodies (EMA) is the best strategy for all degrees of mucosal abnormality using our test combination. Reliance upon immunoassay titre is not as effective, and cannot be applied consistently across populations in the absence of assay standardization. Guidelines advocating the use of tests should involve experts in laboratory diagnostics and external quality assurance to ensure that errors of generalization do not occur and that test performance is achievable in routine diagnostic use.

A pathogenetic link between non-alcoholic fatty liver disease and celiac disease

Non-alcoholic fatty liver disease (NAFLD) has recently been recognized as the leading cause of the abnormalities in the liver function tests in the Western countries. Celiac disease (CD) is a permanent immunological intolerance to gluten proteins in genetically predisposed individuals. CD has been reported in 4-13 % of the cases with steatohepatitis, although the pathogenesis of the liver steatosis in CD patients is unclear. Based on the literature data, it can be concluded that the inclusion of serological markers of CD should be a part of the general workup in the patients with steatosis when other causes of the liver disease are excluded and in the patients with NAFLD when metabolic risk factors are not evident.

Celiac disease markers in patients with liver diseases: A single center large scale screening study

AIM: To study the coincidence of celiac disease, we tested its serological markers in patients with various liver diseases.

METHODS: Large-scale screening of serum antibodies against tissue transglutaminase (tTG), and deamidated gliadin using enzyme-linked immunosorbent assay and serum antibodies against endomysium using immunohistochemistry, in patients with various liver diseases (n = 962) and patients who underwent liver transplantation (OLTx, n = 523) was performed. The expression of tTG in liver tissue samples of patients simultaneously suffering from celiac disease and from various liver diseases using immunohistochemistry was carried out. The final diagnosis of celiac disease was confirmed by histological analysis of small-intestinal biopsy.

RESULTS: We found that 29 of 962 patients (3%) with liver diseases and 5 of 523 patients (0.8%) who underwent OLTx were seropositive for IgA and IgG anti-tTG antibodies. However, celiac disease was biopsy-diagnosed in 16 patients: 4 with autoimmune hepatitis type I, 3 with Wilson's disease, 3 with celiac hepatitis, 2 with primary sclerosing cholangitis, 1 with primary biliary cirrhosis, 1 with Budd-Chiari syndrome, 1 with toxic hepatitis, and 1 with non-alcoholic steatohepatitis. Unexpectedly, the highest prevalence of celiac disease was found in patients with Wilson's disease (9.7%), with which it is only rarely associated. On the other hand, no OLTx patients were diagnosed with celiac disease in our study. A pilot study of the expression of tTG in liver tissue using immunohistochemistry documented the overexpression of this molecule in endothelial cells and periportal hepatocytes of patients simultaneously suffering from celiac disease and toxic hepatitis, primary sclerosing cholangitis or autoimmune hepatitis type I.

CONCLUSION: We suggest that screening for celiac disease may be beneficial not only in patients with associated liver diseases, but also in patients with Wilson's disease.

A myriad of pathways to NASH

Nonalcoholic steatohepatitis (NASH) is defined histopathologically by the presence of macrovesicular steatosis, cellular ballooning, and inflammation. NASH represents a complex multifactorial disease that typically occurs within the context of the metabolic syndrome. NASH lacks homogeneity, and other forms of NASH can present atypically. Less than 50% of patients with NASH respond to pharmacologic treatment, which speaks to this heterogeneity. The authors discuss drugs, disease entities, and nutritional states that can cause or exacerbate underlying NASH indirectly through worsening insulin resistance or directly by interfering with lipid metabolism, promoting oxidative injury, or activating inflammatory pathways.

Selected disorders of malabsorption

Malabsorption syndrome encompasses numerous clinical entities that result in chronic diarrhea, abdominal distention, and failure to thrive. These disorders may be congenital or acquired and include cystic fibrosis and Shwachman-Diamond syndrome; the rare congenital lactase deficiency; glucose-galactose malabsorption; sucrase-isomaltase deficiency; adult-type hypolactasia leading to acquired lactose intolerance. The pathology may be due to impairment in absorption or digestion of nutrients resulting in Nutritional deficiency, gastrointestinal symptoms, and extra gastrointestinal symptoms. Treatment is aimed at correcting the deficiencies and symptoms to improve quality of life. Common disorders of malabsorption celiac disease, pernicious anemia, and lactase deficiency are discussed in this article.

Cryptogenic chronic hepatitis and its changing guise in adults

Cryptogenic chronic hepatitis is a disease that is unexplained by conventional clinical, laboratory and histological findings, and it can progress to cirrhosis, develop hepatocellular carcinoma, and require liver transplantation. The goals of this review are to describe the changing phenotype of cryptogenic chronic hepatitis in adults, develop a diagnostic algorithm appropriate to current practice, and suggest treatment options. The frequency of cryptogenic hepatitis is estimated at 5.4%. Cryptogenic cirrhosis is diagnosed in 5-30% of patients with cirrhosis, and it is present in 3-14% of adults awaiting liver transplantation. Nonalcoholic fatty liver disease has been implicated in 21-63% of patients, and autoimmune hepatitis is a likely diagnosis in 10-54% of individuals. Viral infections, hereditary liver diseases, celiac disease, and unsuspected alcohol or drug-induced liver injury are recognized infrequently in the current cryptogenic population. Manifestations of the metabolic syndrome heighten the suspicion of nonalcoholic fatty liver disease, and the absence of hepatic steatosis does not discount this possibility. The diagnostic scoring system of the International Autoimmune Hepatitis Group can support the diagnosis of autoimmune hepatitis in some patients. Certain genetic mutations may have disease-specificity, and they suggest that some patients may have an independent and uncharacterized disease. Corticosteroid therapy is effective in patients with autoimmune features, and life-style changes and specific therapies for manifestations of the metabolic syndrome are appropriate for all obese patients. The 1- and 5-year survivals after liver transplantation have ranged from 72-85% to 58-73%, respectively.

Meta-analysis: Coeliac disease and hypertransaminasaemia

BACKGROUND

There may be a positive association between coeliac disease and serum hypertransaminasaemia but evidence is conflicting.

AIMS

To conduct a systematic review and meta-analysis to determine the prevalence of coeliac disease in adults presenting with cryptogenic serum hypertransaminasaemia and the prevalence of hypertransaminasaemia in patients with newly diagnosed coeliac disease.

METHODS

MEDLINE and EMBASE were searched up to August 2010. Case series and case-control studies recruiting adults with either cryptogenic hypertransaminasaemia that applied serological tests for coeliac disease and/or distal duodenal biopsy to participants or newly diagnosed biopsy-proven coeliac disease that assessed serum transaminases were eligible. The pooled prevalence of coeliac disease in individuals presenting with abnormal serum transaminases and the pooled prevalence of hypertransaminasaemia in newly diagnosed coeliac disease were calculated with 95% confidence intervals (CI).

RESULTS

Eleven eligible studies were identified. Pooled prevalences of positive coeliac serology and biopsy-proven coeliac disease in cryptogenic hypertransaminasaemia were 6% (95% CI 3% to 10%) and 4% (95% CI 1% to 7%) respectively. Pooled prevalence of abnormal serum transaminases in newly diagnosed coeliac disease was 27% (95% CI 13% to 44%). Exclusion of gluten led to normalisation of serum transaminase levels in 63% to 90% of patients within 1 year.

CONCLUSIONS

Undetected coeliac disease is a potential cause for cryptogenic hypertransaminasaemia in 3% to 4% of cases. More than 20% of individuals with newly diagnosed coeliac disease may have abnormal serum transaminases and these normalise on a gluten-free diet in the majority of cases.

Testing for gluten-related disorders in clinical practice: the role of serology in managing the spectrum of gluten sensitivity

Immunoglobulin A tissue transglutaminase is the single most efficient serological test for the diagnosis of celiac disease. It is well known that immunoglobulin A tissue transglutaminase levels correlate with the degree of intestinal damage, and that values can fluctuate in patients over time. Serological testing can be used to identify symptomatic individuals that need a confirmatory biopsy, to screen at-risk populations or to monitor diet compliance in patients previously diagnosed with celiac disease. Thus, interpretation of serological testing requires consideration of the full clinical scenario. Antigliadin tests are no longer recommended for the diagnosis of classical celiac disease. However, our understanding of the pathogenesis and spectrum of gluten sensitivity has improved, and gluten-sensitive irritable bowel syndrome patients are increasingly being recognized. Studies are needed to determine the clinical utility of antigliadin serology in the diagnosis of gluten sensitivity.

Hepatobiliary manifestations of gastrointestinal and nutritional disorders

Hepatobiliary manifestations of gastrointestinal and nutritional disorders can occur as part of the clinical spectrum of the underlying disease or as a consequence of the treatment of the disease. This article reviews aspects of pathogenesis, diagnosis, and management of hepatobiliary manifestations associated with a selection of gastrointestinal and nutritional disorders including inflammatory bowel disease, celiac disease, Whipple's disease, and parenteral nutrition associated disorders.

Diagnostic immunology in celiac disease

Serum autoantibodies to transglutaminase and endomysium are found in the majority of patients with celiac disease, an autoimmune multisystem disorder affecting approximately 1% of Western and Middle-Eastern populations. Detection of these antibodies plays a crucial role in the diagnosis of celiac disease. The aim of this review is to summarize recent publications in this field, with particular focus on the applications and limitations of celiac autoantibody testing in routine clinical practice.

Duodenal biopsy may be avoided when high transglutaminase antibody titers are present

AIM: To evaluate the predictive value of tissue transglutaminase (tTG) antibodies for villous atrophy in adult and pediatric populations to determine if duodenal biopsy can be avoided.

METHODS: A total of 324 patients with celiac disease (CD; 97 children and 227 adults) were recruited prospectively at two tertiary centers. Human IgA class anti-tTG antibody measurement and upper gastrointestinal endoscopy were performed at diagnosis. A second biopsy was performed in 40 asymptomatic adults on a gluten-free diet (GFD) and with normal tTG levels.

RESULTS: Adults showed less severe histopathology (26% vs 63%, P < 0.0001) and lower tTG antibody titers than children. Levels of tTG antibody correlated with Marsh type in both populations (r = 0.661, P < 0.0001). Multiple logistic regression revealed that only tTG antibody was an independent predictor for Marsh type 3 lesions, but clinical presentation type and age were not. A cut-off point of 30 U tTG antibody yielded the highest area under the receiver operating characteristic curve (0.854). Based on the predictive value of this cut-off point, up to 95% of children and 53% of adults would be correctly diagnosed without biopsy. Despite GFDs and decreased tTG antibody levels, 25% of the adults did not recover from villous atrophy during the second year after diagnosis.

CONCLUSION: Strongly positive tTG antibody titers might be sufficient for CD diagnosis in children. However, duodenal biopsy cannot be avoided in adults because disease presentation and monitoring are different.

Histological abnormalities of the small bowel mucosa in cirrhosis and portal hypertension

AIM: To study the small bowel (SB) mucosa on biopsy in cirrhotic patients with portal hypertension and in non-cirrhotic controls and grade findings according to the Marsh criteria.

METHODS: We prospectively enrolled 51 consecutive patients undergoing an upper endoscopy for their routine medical care. Twenty five patients with cirrhosis and portal hypertension were compared to 26 controls. We obtained coeliac serology and multiple upper small bowel biopsies on all 51 patients. A GI pathologist interpreted biopsies and graded findings according to the Marsh criteria. We assessed equivalence in Marsh grade between cirrhotic and non-cirrhotic controls using the Mann-Whitney test for equivalence.

RESULTS: Gender, ethnicity and age were similar between both groups. Marsh grades were equivalent between the groups. Grade of 0 was present in 96% and grade of 1 was present in 4% of both groups and there was no villus atrophy or decrease in villus/crypt ratio in patients with portal hypertension.

CONCLUSION: This study provides evidence for the lack of villus atrophy in patients with cirrhosis and portal hypertension, and supports the continuous reliance on the Marsh criteria when the diagnosis of coeliac disease is to be made in the presence of cirrhosis.

Systematic review: The evidence base for long-term management of coeliac disease

BACKGROUND

While gluten-free diet is an effective treatment for coeliac disease, the need for and goals of long-term management of patients are poorly defined.

AIM

To review systematically the complications and associations of coeliac disease, to identify potential risk factors, to define ways of assessing risk factors and to provide a strategy for management.

METHODS

Review of medical literature from 1975.

RESULTS

There is an increasing list of potential complications and/or conditions associated with coeliac disease, in particular, autoimmune disease, malignancy and bone disease. Risk factors that may predict or influence long-term outcomes include genetic susceptibility, environmental factors predominantly gluten ingestion, persistent small intestinal inflammation/injury and nutritional deficiencies. Genotyping of patients is yet to have an established clinical role in long-term management. Assessment of adherence to the gluten-free diet largely relies upon skilled dietary history, but the ultimate test is duodenal histopathology, which is the only currently established means of assessing healing. Symptoms, serology or other non-invasive means are poor predictors of healing and the likelihood of complications.

CONCLUSION

Evidence (albeit limited) that adherence to a gluten-free diet and mucosal healing prevent and/or ameliorate complications indicates that a planned long-term strategy for follow-up is essential.

Celiac disease and non-organ-specific autoantibodies in patients with chronic hepatitis C virus infection

OBJECTIVE

Considering that celiac disease (CD) is an autoimmune-based entity and the hepatitis C virus is suspected of being able to trigging autoimmune reactions, it has been hypothesized that hepatitis C virus infection might predispose to CD. The aim of this study was to investigate CD-related antibodies in a large series of hepatitis C virus-infected subjects that were also tested for non-organ-specific autoantibodies (NOSA) as indirect marker of autoimmune disorders.

METHODS

Two hundred and forty-four patients with chronic hepatitis C virus infection (HCV-patients) and 121 patients with HCV-negative liver disease (non-HCV-patients) underwent NOSA determination and celiac serology (firstly, anti-tissue transglutaminase antibodies, then the cases which tested positive were subsequently evaluated for the presence of antiendomysial antibodies). Serum samples from 42 of the HCV-patients who underwent interferon-alpha therapy after enrollment were tested for celiac antibodies and NOSA even after stopping treatment. Additionally, sera from 1,230 blood donors were assayed for celiac serology as healthy control population.

RESULTS

Positive anti-endomysial antibodies (AEA) were found in 5/244 (2%) HCV-patients, 1/121 (0.8%) non-HCV-patients and 2/1,230 (0.16%) blood donors, with a significant difference between HCV-patients and blood donors (P = 0.02; Odds ratio 12.8; 95% Confidence Interval 2.4-66). NOSA were found in 51 HCV-patients but only one of them had positive AEA. Eight out of 42 HCV-patients treated with interferon-alpha developed NOSA under therapy and none of them had CD antibodies.

CONCLUSIONS

AEA occur in 2% of HCV-patients and their presence is independent of other patterns of autoimmunity.

Strongly positive tissue transglutaminase antibodies are associated with Marsh 3 histopathology in adult and pediatric celiac disease

GOALS

Our objective was to determine whether high serologic IgA tissue transglutaminase antibodies (TTGA) are exclusively associated with celiac disease (CD).

BACKGROUND

IgA TTGA are found in the serum of most individuals with CD. This serologic marker is used to screen individuals with suspected CD for duodenal biopsy, the gold standard of CD diagnosis. Data suggest strongly positive IgA TTGA >or= 100 units are highly specific for CD histopathology in pediatric patients and may be sufficient for diagnosis.

STUDY

Records of adult and pediatric subjects in the celiac study at the University of Utah and University of California Irvine were reviewed for strongly positive TTGA. Pathology reports from duodenal biopsies of subjects with IgA TTGA >or= 100 units were graded as 0 to 3 by modified Marsh criteria.

RESULTS

From a pool of 1882 subjects with IgA TTGA assayed, 208 had IgA TTGA >or= 100 units. Seventy-six of these, including 28 children and 48 adults, also had duodenal biopsies. Villous atrophy (Marsh 3 histopathology) was found on biopsy in 73 (96%) of these subjects. The remaining 3 subjects had intermediate Marsh histology. One (Marsh 1) had a complete serologic response to a gluten-free diet and 2 had Marsh 2 lesions and positive endomysium, making early CD most likely.

CONCLUSIONS

IgA TTGA >or= 100 units occur almost exclusively in the setting of Marsh 3 duodenal histopathology in adults and children. Rare cases without villous atrophy were marked by intermediate Marsh changes suggestive of early CD. IgA TTGA >or= 100 arbitrary units indicate duodenal changes consistent with CD.

Co-occurrence of IgA antibodies against ethanol metabolites and tissue transglutaminase in alcohol consumers: correlation with proinflammatory cytokines and markers of fibrogenesis

IgA antibodies to tissue transglutaminase have been suggested to be specific indicators of celiac disease. However, no studies have addressed the relationships between such antibodies and alcohol abuse, which is also a common cause of IgA-isotype immune responses and tissue injury in the gastrointestinal tract and liver. Here, measurements of specific IgAs against tissue transglutaminase and proteins modified by acetaldehyde, the first metabolite of ethanol, showed significantly higher levels of both antibodies in alcoholic liver disease patients than in healthy controls or heavy drinkers without liver disease. These antibodies also significantly co-occurred in heavy drinkers without liver disease, moderate drinkers, and abstainers, and correlated with biomarkers of alcohol consumption, proinflammatory cytokines and markers of fibrogenesis. The data suggests a link between such immune responses, perturbations in cytokine profiles and fibrogenesis, which should be implicated in studies on the pathogenesis and diagnosis of ethanol-induced tissue injury and celiac disease.

[Utility of liver biopsy in the etiologic diagnosis of biochemical liver abnormalities of unknown cause]

INTRODUCTION

To establish the diagnostic usefulness of liver biopsy (LB) and its influence on the therapeutic approach in patients with persistent abnormal liver tests of unknown cause.

METHODS

The 1135 LB performed between January 1999 and January 2007 were retrospectively evaluated. Patients with a strongly suspected diagnosis were excluded. One hundred and twelve patients with chronic elevation of aminotransferases (103 patients), gamma-glutamyltransferase (GGT) (7 patients) and ferritin (2 patients) were included in the analysis.

RESULTS

The most common diagnoses were normal liver (35 patients, group 1), minimal changes (15 patients, group 2), bland steatosis (23 patients, group 3), non-alcoholic steatohepatitis (NASH) (17 patients, group 4), and chronic hepatitis (eight patients, group 5). Three patients had tuberculosis of the liver and the remaining 11 had other diagnoses. Ferritinemia was the only parameter significantly lower in group 1 than in groups 2 (p = 0.038), 3 (p = 0.023), and 4 (p < 0.001). Transaminase levels lacked discriminatory value except in chronic hepatitis (p = 0.008). Alkaline phosphatase levels (p = 0.003) were lower in group 4 than in group 1. Triglyceride levels were higher in group 3 (p = 0.009) and group 4 (p = 0.008) than in group 1. Ultrasonography detected steatosis in 28 of the 40 patients with fatty liver (specificity = 0.94; sensitivity = 0.70).

CONCLUSIONS

LB modified the therapeutic approach only in the three patients with hepatic tuberculosis. LB confirmed ultrasonographic findings of steatosis and differentiated bland steatosis from NASH, but did not influence the therapeutic approach. Most patients with normal findings on ultrasonography had normal or near-normal biopsies. The indication for LB should be individualized.

The liver in celiac disease

Celiac disease is a common (1% prevalence) chronic immune-mediated disorder of the small intestine induced by dietary wheat, barley, and rye. Several hepatic disorders have been described in association with celiac disease. Isolated hypertransaminasemia with nonspecific histologic changes in a liver biopsy is the commonest hepatic presentation of celiac disease. A gluten-free diet normalizes liver enzymes and histologic changes in most patients. Moreover, celiac disease can coexist with autoimmune liver disorders such as autoimmune hepatitis, primary biliary cirrhosis, and primary sclerosing cholangitis. Celiac disease has increasingly been reported with a variety of other liver diseases. Thus, the hepatologist needs to consider celiac disease in the differential of abnormal liver blood tests and to be aware of the clinical implications of this frequent disease in patients with liver disorders. The possible mechanisms of liver injury and those common factors that explain the association of celiac disease with liver disorders are discussed. The aims of this article are (1) to review the spectrum and pathogenesis of liver injury related to celiac disease and (2) to provide direction to those caring for patients with chronic liver diseases regarding the detection and effective treatment of celiac disease.

Testing for IgG class antibodies in celiac disease patients with selective IgA deficiency. A comparison of the diagnostic accuracy of 9 IgG anti-tissue transglutaminase, 1 IgG anti-gliadin and 1 IgG anti-deaminated gliadin peptide antibody assays

BACKGROUND

To evaluate the diagnostic characteristics of commercially available IgG anti-tTG assays in selective IgA deficiency (SIgAD), we tested different IgG anti-tTG methods and compared the results with those obtained from two other tests: one for IgG anti-gliadin (AGA) and one for IgG to deaminated gliadin peptides (DGP).

METHODS

20 CD patients with SIgAD and 113 controls (9 patients with SIgAD without CD; 54 patients with chronic liver disease; 50 healthy subjects) were tested with 9 IgG anti-tTG assays (2 of which are enriched with gliadin peptides), one IgG AGA assay and one IgG anti-DGP assay.

RESULTS

Using optimal cutoffs as determined by ROC curves, the sensitivity of IgG anti-tTG methods ranged from 75% (1 kit) to 95% (7 kits) and the specificity from 94% (1 kit) to 100% (5 kits). Sensitivity and specificity were 40% and 87% for IgG AGA, and 80% and 98% for IgG anti-DGP, respectively.

CONCLUSIONS

All IgG anti-tTG methods evaluated are reliable serologic assays for the diagnosis of CD in patients with SIgAD and perform better than the gliadin-based assays used in this study. The tests containing both tTG and gliadinic peptides are burdened by a lower specificity than the anti-tTG assays.

Deamidated Gliadin Peptides as Targets for Celiac Disease‐Specific Antibodies

Celiac disease (CD) is an (auto)immunologically mediated intestinal intolerance against proteins from wheat (gluten) and related cereal proteins. Tissue transglutaminase (tTG) has been identified as the autoantigen in CD. Although ultimate diagnosis is based on histological analysis of small intestinal mucosa obtained via tissue biopsy, assessment of autoantibodies can provide substantial help in the evaluation of CD. Gliadin antibodies are directed against the native disease-provoking cereal proteins. Despite their initial usefulness, these antibodies have lost diagnostic importance due to their poor specificity and sensitivity as CD markers. Recently, it was found, however, that gliadin antibodies from sera of patients with active CD preferentially recognized deamidated gliadin peptides. The use of deamidated gliadin peptides in immunoassays has significantly improved the usefulness of gliadin antibodies in diagnosis of CD to that observed with autoantibody assay methods (endomysium antibodies, antibodies against tTG). The antibody epitopes (B-cell epitopes) reflect substrate specificity of tTG and resemble peptide sequences known to be strongly T-cell stimulatory (T-cell epitopes) in CD. The assay applying deamidated gliadin peptides measures a new species of antibodies, which is different from conventional gliadin antibodies as well as from autoantibodies and will likely provide new information on pathophysiological mechanisms of CD.

Adult population screening for coeliac disease: comparison of tissue-transglutaminase antibody and anti-endomysial antibody tests

Serological screening tests for coeliac disease have significantly advanced the diagnosis of this condition. The very high specificity (almost 100%) of anti-endomysial antibody detection has been repeatedly confirmed, whereas a lower specificity (90-95%) is found with anti-tissue transglutaminase antibody assays. In the study by Malekzadeh and colleagues, a group of study participants were identified with raised anti-tissue transglutaminase antibodies, but the endomysial antibody test was negative in 86%. Although many of these participants were found to have raised intra-epithelial lymphocytes in their small intestinal mucosa, there is currently insufficient evidence to confidently diagnose gluten-sensitive disease in these patients. Hence, their report that a minimum prevalence of 1:104 of gluten sensitivity is found in the general population of Iran is likely to be an over-estimate and requires confirmation.

Liver involvement in celiac disease

Celiac disease may present as a cryptogenic liver disorder being found in 5-10 % of patients with a persistent and cryptogenetic elevation of serum aminotransferase activity. In fact, a wide spectrum of liver injuries in children and adults may be related to CD and in particular: (1) a mild parenchymal damage characterised by absence of any clinical sign or symptom suggesting a chronic liver disease and by non-specific histological changes reversible on a gluten-free diet; (2) a chronic inflammatory liver injury of autoimmune mechanism, including autoimmune hepatitis, primary sclerosing cholangitis and primary biliary cirrhosis, that may lead to fibrosis and cirrhosis, generally unaffected by gluten withdrawal and necessitating an immunosuppressive treatment; (3) a severe liver failure potentially treatable by a gluten-free diet. Such different types of liver injuries may represent a spectrum of a same disorder where individual factors, such as genetic predisposition, precocity and duration of exposure to gluten may influence the reversibility of liver damage. A rigorous cross-checking for a asymptomatic liver damage in CD individuals and conversely, for CD in any cryptogenic liver disorder including end-stage liver failure is recommended.

Diagnosis of celiac disease

Celiac disease is an immune mediated enteropathy initiated by ingestion of gluten, in genetically susceptible individuals. With changing epidemiology, celiac disease initially thought to affect only Europeans, has been increasingly reported from other parts of the world including India. However, its true prevalence in India is still not known, as the diagnosis is being missed. The gold standards for diagnosis have been characteristic small intestinal mucosal changes on gluten and a full clinical remission on its removal from the diet. Presence of serological antibodies, which disappear on gluten free diet further confirms the diagnosis. The understanding of the histopathology of celiac disease has changed over the years. The small bowel mucosal lesion of celiac disease is an evolutionary process with normal mucosal architecture and an increase in intraepithelial lymphocytes at one end of the spectrum and classical flat mucosa at the other. In the Indian subcontinent celiac disease has a heterogeneous histological presentation and the diagnosis may be missed if it is based only on severe mucosal changes or the serology is not considered when moderate or mild mucosal changes are present. The last two decades have shown that antiendomysical (Anti EMA) and anti tissue transglutaminase antibodies (anti-tTGA) have a sensitivity and specificity of more than 95% to diagnose celiac disease. Anti EMA tests being operator dependent are more liable to errors and anti- tTGA may be preferred for large scale screening. However, the different source of tTGA antigen, varied techniques of production and the use of arbitrary units by different commercial kits can influence the diagnostic accuracy of the anti-tTGA assay. There is a strong genetic association of celiac disease with HLA-DQ2 or DQ8. The presence of HLA-DQ2 hetrodimer in more than 97% of a group of North Indian patients with celiac disease indicates that this population has a similar genetic risk for the disease. HLA DQ2 typing can be used for ruling out celiac disease where the diagnosis is equivocal as it has a negative predictive value of greater than 95%. Given the protean clinical manifestation and the heterogeneous histology a standard algorithm for diagnosis of celiac disease is important.

Unusual manifestations of celiac disease

Celiac disease is multifaced autoimmune disorder with several extraintestinal manifestations and connections to other autoimmune diseases and other conditions. The recognition of the complex clinical picture of the disease helps doctors to search and diagnose celiac disease even if the gastrointestinal symptoms are lacking. Individuals at risk for celiac disease should be thoroughly investigated and individuals with unusual manifestations of the disease should be screened actively.

Update on the evaluation and diagnosis of celiac disease

PURPOSE OF REVIEW

Our understanding of the pathophysiology of celiac disease has advanced with associated improvement in diagnostic modalities. Recent studies have placed the prevalence of celiac disease in Western populations at between 1:250 and 1:67. Celiac disease is common throughout the world and most cases go undiagnosed. Understanding the risk factors, clinical presentations and diagnostic modalities is necessary to identify and treat patients with this commonly misdiagnosed disorder.

RECENT FINDINGS

Increased prevalence of celiac disease in individuals with autoimmune diseases, reduced bone mineral density and undiagnosed liver disease have been confirmed. However, celiac disease may not be associated with Down's syndrome or epilepsy. Evidence supports high sensitivity and specificity of endomysial- and tissue transglutaminase-based tests in most settings. In children, high or low tissue transglutaminase levels may preclude the need for duodenal biopsy. Cost-effectiveness studies suggest using tissue transglutaminase or endomysial initially, while distal duodenal or jejunal biopsy may confirm celiac disease in the absence of proximal changes.

SUMMARY

There is insufficient evidence to support mass screening for celiac disease. However, case finding in individuals with risk factors for celiac disease is recommended. Further study is necessary to define diagnostic algorithms and target populations likely to benefit from testing.