Autoantibodies to tissue transglutaminase as predictors of celiac disease

Liver manifestation of patients with celiac disease: A single center experience

OBJECTIVES

Characterize the clinicopathologic features of liver biopsies from patients with celiac disease (CD).

METHODS

Single center, retrospective search for liver biopsies from patients with CD.

RESULTS

36 unique patients were included, median age of 46 years (range: 2-75), including 5 pediatric patients, with an overall female predominance (25, 69 %) but in in children a male predominance was seen (p = 0.023). Most cases (75 %) had an underlying condition including autoimmune hepatitis (AIH) (11 %), AIH/primary biliary cholangitis (PBC) overlap (3 %) and PBC (3 %). The median body mass index was 28, with 4 (11 %) underweight and 22 (61 %) overweight/obese patients. The most common histologic pattern was steatosis (18, 50 %), considered severe in 5 (14 %) and in 7 (19 %) regarded as steatohepatitis. The other histologic patterns included a nonspecific portal and/or lobular inflammation ("celiac hepatitis") in 9 cases (25 %), autoimmune hepatitis (3, 8 %), chronic cholestatic pattern (3, 8 %), chronic hepatitis (1, 3 %), acute lobular hepatitis (1, 3 %) and stablished cirrhosis (1, 3 %). Additionally, 2 of the cases with steatosis show cirrhosis.

CONCLUSIONS

The biopsy findings from patients with CD are heterogenous and in most represent a concomitant underlying disease, particularly metabolic dysfunction-associated steatotic liver disease. Additionally, CD injury should remain in the differential diagnosis in liver biopsies with a nonspecific portal and/or lobular inflammation.

Celiac Disease: A Forty-Year Analysis in an Italian Referral Center

BACKGROUND

Celiac disease (CD) is an autoimmune disorder triggered by gluten ingestion. Herein, we assessed clinical, serological and histopathological findings of a single-center, large cohort of CD patients diagnosed and followed-up over forty years.

METHODS

From January 1980 to December 2020, 1547 CD patients (1170 females; age range: 8-81 years; F:M ratio = 3.1:1) were diagnosed in an Italian tertiary referral center. Comorbidities and complications were recorded at diagnosis and during follow-up.

RESULTS

CD diagnoses quadrupled after 2000. The most frequent phenotype was the non-classical CD (63.3%), and the most prevalent histotype was Marsh 3C (44.7%). Gastrointestinal manifestations, detectable in 51% of patients, were diarrhea (24.3%), bloating (28%) and aphthous stomatitis (19.7%). The most common CD-associated disorder was osteopenia (59.9%), predominant in females (64.3%); extraintestinal manifestations included anemia (35.8% iron-deficiency; 87% folic acid malabsorption), cryptogenic hypertransaminasemia (27.9%), and recurrent miscarriages (11.5%). Thyroiditis (26.9%), type 1 diabetes mellitus (2.9%), and dermatitis herpetiformis (1.4%) were the most common CD-related autoimmune disorders. Six patients had inflammatory bowel disease. Complications and mortality rate occurred in 1.8% and 1.9%, respectively.

CONCLUSIONS

This single-center, large cohort analysis confirmed that CD presentation changed over the years, with an increase of non-classical and subclinical clinical phenotypes.

Celiac Disease-Related Conditions: Who to Test?

Celiac disease (CeD) is a chronic immune-mediated condition triggered by gluten consumption in genetically predisposed individuals. Approximately 1% of the general population is affected by the disorder. Disease presentation is heterogeneous and, despite growing awareness among physicians and the public, it continues to be underestimated. The most effective strategy for identifying undiagnosed CeD is proactive case finding through serologic testing in high-risk groups. We reviewed the most recent evidence on the association between CeD and more than 20 conditions. In light of this review, CeD screening is recommended in individuals with (1) autoimmune disease and accompanying symptoms suggestive of CeD; (2) diseases that may mimic CeD (eg, irritable bowel syndrome [IBS], inflammatory bowel disease [IBD], and microscopic colitis); and (3) among patients with conditions with a high CeD prevalence: first-degree relatives, idiopathic pancreatitis, unexplained liver enzyme abnormalities, autoimmune hepatitis, primary biliary cholangitis, hyposplenism or functional asplenia with severe bacterial infection, type 1 diabetes mellitus, Hashimoto's thyroiditis and Graves' disease, Sjögren's syndrome, dermatitis herpetiformis, recurrent aphthous syndrome and enamel defects, unexplained ataxia, peripheral neuropathy, delayed menarche or premature menopause, Down syndrome, Turner syndrome, Williams syndrome, chronic fatigue syndrome, IgA nephropathy, and IgA deficiency. CeD serology should be the initial step in the screening process. However, for patients with any of the aforementioned disorders who are undergoing upper endoscopy, biopsies should be performed to rule out CeD.

Coeliac disease: the paradox of diagnosing a food hypersensitivity disorder with autoantibodies

Serum antibodies to the autoantigen transglutaminase 2 (TG2) are increasingly harnessed to diagnose coeliac disease. Diagnostic guidelines for children give recommendation for a no-biopsy-based diagnosis through detection of high amounts of IgA anti-TG2 antibodies in serum with confirmation of positivity in a separate blood sample by characteristic autoantibody-staining of tissue. While measurement of IgA anti-TG2 also is important in the diagnostic workup of adults, the adult guidelines still mandate examination of gut biopsies. This requirement might well change in the future, as might the necessity for confirming autoantibody positivity by tissue staining. The key role of autoantibody serology for diagnosis of coeliac disease is paradoxical. Coeliac disease was considered, and still can be considered, a food intolerance disorder where autoantibodies at face value are out of place. The immunological mechanisms underlying the formation of autoantibodies in response to gluten exposure have been dissected. This review presents the current insights demonstrating that the autoantibodies in coeliac disease are intimately integrated in the maladapted immune response to gluten.

Accuracy of the No-Biopsy Approach for the Diagnosis of Celiac Disease in Adults: A Systematic Review and Meta-Analysis

BACKGROUND & AIMS

Current international guidelines recommend duodenal biopsies to confirm the diagnosis of celiac disease in adult patients. However, growing evidence suggests that immunoglobulin A (IgA) anti-tissue transglutaminase (tTg) antibody levels ≥10 times the upper limit of normal (ULN) can accurately predict celiac disease, eliminating the need for biopsy. We performed a systematic review and meta-analysis to evaluate the accuracy of the no-biopsy approach to confirm the diagnosis of celiac disease in adults.

METHODS

We systematically searched MEDLINE, EMBASE, Cochrane Library, and Web of Science from January 1998 to October 2023 for studies reporting the sensitivity and specificity of IgA-tTG ≥10×ULN against duodenal biopsies (Marsh grade ≥2) in adults with suspected celiac disease. We used a bivariate random effects model to calculate the summary estimates of sensitivity, specificity, and positive and negative likelihood ratios. The positive and negative likelihood ratios were used to calculate the positive predictive value of the no-biopsy approach across different pretest probabilities of celiac disease. The methodological quality of the included studies was evaluated using the QUADAS-2 tool. This study was registered with PROSPERO, number CRD42023398812.

RESULTS

A total of 18 studies comprising 12,103 participants from 15 countries were included. The pooled prevalence of biopsy-proven celiac disease in the included studies was 62% (95% confidence interval [CI], 40%-83%). The proportion of patients with IgA-tTG ≥10×ULN was 32% (95% CI, 24%-40%). The summary sensitivity of IgA-tTG ≥10×ULN was 51% (95% CI, 42%-60%), and the summary specificity was 100% (95% CI, 98%-100%). The area under the summary receiver operating characteristic curve was 0.83 (95% CI, 0.77 - 0.89). The positive predictive value of the no-biopsy approach to identify patients with celiac disease was 65%, 88%, 95%, and 99% if celiac disease prevalence was 1%, 4%, 10%, and 40%, respectively. Between-study heterogeneity was moderate (I2 =30.3%), and additional sensitivity analyses did not significantly alter our findings. Only 1 study had a low risk of bias across all domains.

CONCLUSION

The results of this meta-analysis suggest that selected adult patients with IgA-tTG ≥10×ULN and a moderate to high pretest probability of celiac disease could be diagnosed without undergoing invasive endoscopy and duodenal biopsy.

Phenome-wide Mendelian randomization analysis reveals multiple health comorbidities of coeliac disease

BACKGROUND

Coeliac disease (CeD) has been associated with a broad range of diseases in observational data; however, whether these associations are causal remains undetermined. We conducted a phenome-wide Mendelian randomization analysis (MR-PheWAS) to investigate the comorbidities of CeD.

METHODS

Single nucleotide polymorphisms (SNPs) associated with CeD at the genome-wide significance threshold and without linkage disequilibrium (R2 <0.001) were selected from a genome-wide association study including 12,041 CeD cases as the instrumental variables. We first constructed a polygenic risk score for CeD and estimated its associations with 1060 unique clinical outcomes in the UK Biobank study (N = 385,917). We then used two-sample MR analysis to replicate the identified associations using data from the FinnGen study (N = 377,277). We performed a secondary analysis using a genetic instrument without extended MHC gene SNPs.

FINDINGS

Genetic liability to CeD was associated with 68 clinical outcomes in the UK Biobank, and 38 of the associations were replicated in the FinnGen study. Genetic liability to CeD was associated with a higher risk of several autoimmune diseases (type 1 diabetes and its complications, Graves' disease, Sjögren syndrome, chronic hepatitis, systemic and cutaneous lupus erythematosus, and sarcoidosis), non-Hodgkin's lymphoma, and osteoporosis and a lower risk of prostate diseases. The associations for type 1 diabetes and non-Hodgkin's lymphoma attenuated when excluding SNPs in the MHC region, indicating shared genetic aetiology.

INTERPRETATION

This study uncovers multiple clinical outcomes associated with genetic liability to CeD, which suggests the necessity of comorbidity monitoring among this population.

FUNDING

This project was funded by Karolinska Institutet and the Swedish Research Council.

Autoantibody binding and unique enzyme-substrate intermediate conformation of human transglutaminase 3

Transglutaminase 3 (TG3), the autoantigen of dermatitis herpetiformis (DH), is a calcium dependent enzyme that targets glutamine residues in polypeptides for either transamidation or deamidation modifications. To become catalytically active TG3 requires proteolytic cleavage between the core domain and two C-terminal β-barrels (C1C2). Here, we report four X-ray crystal structures representing inactive and active conformations of human TG3 in complex with a TG3-specific Fab fragment of a DH patient derived antibody. We demonstrate that cleaved TG3, upon binding of a substrate-mimicking inhibitor, undergoes a large conformational change as a β-sheet in the catalytic core domain moves and C1C2 detaches. The unique enzyme-substrate conformation of TG3 without C1C2 is recognized by DH autoantibodies. The findings support a model where B-cell receptors of TG3-specific B cells bind and internalize TG3-gluten enzyme-substrate complexes thereby facilitating gluten-antigen presentation, T-cell help and autoantibody production.

The debate in the diagnosis of coeliac disease - time to go 'no-biopsy'?

PURPOSE OF REVIEW

Duodenal biopsies have been central to making a diagnosis of coeliac disease for the last 70 years. Recent paediatric guidelines have reduced the emphasis on duodenal biopsies with the incorporation of a 'no-biopsy' arm to the diagnostic pathway. This review discusses the no-biopsy approach in adults and highlights advances in alternative (non-biopsy) diagnostic modalities in coeliac disease.

RECENT FINDINGS

Evidence suggests that a no-biopsy approach for the diagnosis of adult coeliac disease is accurate. However, a number of factors still favour duodenal biopsy sampling in specific patient groups. Moreover, several factors need to be considered if this pathway is implemented into local gastroenterology services.

SUMMARY

Duodenal biopsies remain an important step in the diagnosis of adult coeliac disease. However, an alternative approach that removes the necessity for biopsies may be an option in selected adults. If further guidelines incorporate this pathway, then efforts should focus on supporting a dialogue between primary and secondary care to facilitate the appropriate implementation of this approach.

PSMA2 knockdown impacts expression of proteins involved in immune and cellular stress responses in human lung cells

Proteasome subunit alpha type-2 (PSMA2) is a critical component of the 20S proteasome, which is the core particle of the 26S proteasome complex and is involved in cellular protein quality control by recognizing and recycling defective proteins. PSMA2 expression dysregulation has been detected in different human diseases and viral infections. No study yet has reported PSMA2 knockdown (KD) effects on the cellular proteome.

METHODS

We used SOMAScan, an aptamer-based multiplexed technique, to measure >1300 human proteins to determine the impact of PSMA2 KD on A549 human lung epithelial cells.

RESULTS

PSMA2 KD resulted in significant dysregulation of 52 cellular proteins involved in different bio-functions, including cellular movement and development, cell death and survival, and cancer. The immune system and signal transduction were the most affected cellular functions. PSMA2 KD caused dysregulation of several signaling pathways involved in immune response, cytokine signaling, organismal growth and development, cellular stress and injury (including autophagy and unfolded protein response), and cancer responses.

CONCLUSIONS

In summary, this study helps us better understand the importance of PSMA2 in different cellular functions, signaling pathways, and human diseases.

Diagnostic management of patients reporting symptoms after wheat ingestion

Many patients report symptoms after wheat ingestion experiencing a wide spectrum of clinical manifestations. Three possible diagnoses have been recognized: celiac disease (CD), wheat allergy (WA), and non-celiac (gluten) wheat sensitivity (NCGS/NCWS). CD is a chronic immune-mediated disease of the small bowel caused by exposure to dietary gluten in genetically predisposed individuals, with a prevalence of approximately 1%. It is characterized by mucosal inflammation and atrophy following exposure to gluten and improvement after gluten withdrawal. Food allergies are immunological responses to a food antigen. WA is the expression of an immunologically mediated process that can be immunoglobulin E (IgE) or non-IgE mediated; its many symptoms include urticaria/angioedema, asthma, rhinitis, and anaphylaxis. NCGS/NCWS is characterized by gastrointestinal and/or extra-intestinal symptoms after ingestion of gluten-containing food in subjects not affected by CD or WA. The aim of this review is to help physicians and nutritionists diagnose the cause of symptoms reported after wheat ingestion, thus avoiding patient frustration, inappropriate testing, and incorrect or missed diagnoses. An algorithm for the diagnostic approach in these patients is provided, to help to diagnose CD, WA, NCGS/NCWS or to identify possible functional disorders as the wheat-sensitive irritable bowel syndrome. A personalized approach, regular follow-up, and the help of a skilled healthcare professional are mandatory for patients with symptoms following wheat ingestion is provided. A gluten-free-diet is often recommended for patients with self-reported gluten/wheat-dependent symptoms; for patients with symptoms similar to those of functional diseases while there is evidence that a low-FODMAP diet could be the first option.

The seroprevalence of celiac disease in patients with symptoms of irritable bowel syndrome: A cross-sectional study in north of Iran

BACKGROUND

Celiac disease (CD) is a common cause of malabsorption that is definitively diagnosed by abnormal bowel biopsy, symptoms and histologic changes to gluten free diet. The symptoms of irritable bowel syndrome (IBS) are common in our community as the majority of people in Guilan, north of Iran, consume rice daily. Also, a number of celiac patients are unknown, and IBS are mistakenly diagnosed.

OBJECTIVE

This study aimed to evaluate the prevalence of CD among IBS patients.

METHODS

A total of 475 consecutive patients with IBS, confirmed by Rome IV, underwent celiac serological tests antitissue transglutaminase antibodies (IgA-tTG, IgG-tTG) after obtaining a written consent form. In case of positive serological tests, biopsy was performed from small intestine after endoscopyRESULTS: Thirty-one (6.53%, 95% CI: 4.55-9.22) patients were positive for celiac serology. Based on Marsh-Oberhuber criteria, out of 9 patients with positive pathology 77.78% (95% CI: 40.19-96.05) had marsh IIIc. In IBS patients cramp (0.009) and stomach fullness (0.021) were two statistically significant IBS symptoms.

CONCLUSIONS

We suggest physicians to consider celiac examinations for all patients with IBS symptoms, even for patients with no obvious celiac symptoms.

Pathophysiology and immunogenetics of celiac disease

Celiac disease (CD) is a chronic inflammatory enteropathy caused by gluten (protein from wheat, rye and, barley) in genetically predisposed individuals carrying the HLA-DQ2/HLA-DQ8 genotype. This pathology has a multifactorial etiology in which HLA genes, the microbiome, gluten and, other environmental factors are involved in the development of the disease. Its pathogenesis involves both innate and adaptive immunity as well as upregulation of IL-15. The objective of this review is to examine the results of current studies on genetic and environmental variables to better understand the pathogenesis of this enteropathy. The complex etiology of celiac disease makes our understanding of the pathogenesis of the disease incomplete, and a better knowledge of the many genetic and environmental components would help us better understand the pathophysiology of celiac disease.

Frontiers in Celiac Disease: Where Autoimmunity and Environment Meet

Celiac disease is a chronic, immune-mediated enteropathy driven by dietary gluten found in genetically susceptible hosts. It has a worldwide distribution, is one of the most common autoimmune disorders globally, and is the only autoimmune condition for which the trigger is known. Despite advances in characterizing mechanisms of disease, gaps in understanding of celiac disease pathogenesis remain. A "frontier" concept is considering what moves an HLA-DQ2 or DQ8-positive individual from asymptomatic gluten tolerance to celiac disease manifestation. In this arena, environmental triggers, including age at the time of initial gluten exposure, the occurrence of usual childhood viral infections, and microbiome alterations have emerged as key events in triggering the symptomatic disease. Pathologists play a major role in frontier aspects of celiac disease. This includes the discovery that duodenal mucosal histology in follow-up biopsies does not correlate with ongoing patient symptoms, antitissue transglutaminase antibody titers and diet adherence in celiac disease patients. Further, in light of recent evidence that the detection of monoclonal T-cell populations in formalin-fixed biopsies is not specific for type II refractory celiac disease, pathologists should resist performing such analyses until common causes of "apparent" refractoriness are excluded. The promise of therapies in celiac disease has led to clinical trials targeting many steps in the inflammatory cascade, which depend upon a pathologist's confirmation of the initial diagnosis and evaluation of responses to therapies. As pathologists continue to be active participants in celiac disease research, partnering with other stakeholders, we will continue to impact this important autoimmune disease.

Diagnosing coeliac disease: A literature review

Coeliac disease (CD) is an autoimmune gastroenteropathy triggered by gliadin and gliadin-tissue transglutaminase (tTG) complexes. CD is one of the few autoimmune diseases with an accurate, non-invasive serological test. Anti-endomysial, anti-tTG and anti-deaminated gliadin peptides (DGP) antibodies are currently used for serological tests with tTG ELISAs being the superior test. Duodenal biopsy, although invasive, is the gold standard for CD diagnosis. HLA genotyping and flow cytometry can also be used as supplementary tests. The incidence of CD is rising globally although the reasons for this remain unclear. In addition, the true incidence of coeliac disease in African populations remains unknown although recent work suggests that South African populations express the alleles associated with this disease. This review examines the pathogenesis and diagnosis of coeliac disease and considers novel and innovative biomarkers in its diagnosis specifically in an African population.

Systematic review and meta-analysis: the incidence and prevalence of paediatric coeliac disease across Europe

BACKGROUND

Coeliac disease is one of the most prevalent immune-mediated gastrointestinal disorders in children.

AIM

To review the incidence and prevalence of paediatric coeliac disease, and their trends, regionally across Europe, overall and according to age at diagnosis.

METHODS

Systematic review and meta-analysis from January 1, 1950 to December 31, 2019, based on PubMed, CINAHL and the Cochrane Library, searches of grey literature and websites and hand searching of reference lists. A total of 127 eligible studies were included.

RESULTS

The prevalence of previously undiagnosed coeliac disease from screening surveys (histology based) ranged from 0.10% to 3.03% (median = 0.70%), with a significantly increasing annual trend (P = 0.029). Prevalence since 2000 was significantly higher in northern Europe (1.60%) than in eastern (0.98%), southern (0.69%) and western (0.60%) Europe. Large increases in the incidence of diagnosed coeliac disease across Europe have reached 50 per 100 000 person-years in Scandinavia, Finland and Spain. The median age at diagnosis increased from 1.9 years before 1990 to 7.6 since 2000. Larger increases in incidence were found in older age groups than in infants and ages <5 years.

CONCLUSIONS

Paediatric coeliac disease incidence and prevalence have risen across Europe and appear highest in Scandinavia, Finland and Spain. The most recent evidence shows large increases in incidence in most regions, but stabilisation in some (notably Sweden and Finland). Sharp increases in the age at diagnosis may reflect increases in milder and asymptomatic cases diagnosed since reliable serology testing became widely used, through endomysial antibodies after 1990 and tissue transglutaminase antibodies around 2000.

Interplay Between Gluten, HLA, Innate and Adaptive Immunity Orchestrates the Development of Coeliac Disease

Several environmental, genetic, and immune factors create a "perfect storm" for the development of coeliac disease: the antigen gluten, the strong association of coeliac disease with HLA, the deamidation of gluten peptides by the enzyme transglutaminase 2 (TG2) generating peptides that bind strongly to the predisposing HLA-DQ2 or HLA-DQ8 molecules, and the ensuing unrestrained T cell response. T cell immunity is at the center of the disease contributing to the inflammatory process through the loss of tolerance to gluten and the differentiation of HLA-DQ2 or HLA-DQ8-restricted anti-gluten inflammatory CD4⁺ T cells secreting pro-inflammatory cytokines and to the killing of intestinal epithelial cells by cytotoxic intraepithelial CD8⁺ lymphocytes. However, recent studies emphasize that the individual contribution of each of these cell subsets is not sufficient and that interactions between these different populations of T cells and the simultaneous activation of innate and adaptive immune pathways in distinct gut compartments are required to promote disease immunopathology. In this review, we will discuss how tissue destruction in the context of coeliac disease results from the complex interactions between gluten, HLA molecules, TG2, and multiple innate and adaptive immune components.

Tissue Transglutaminase Expression Associates With Progression of Multiple Sclerosis

Objective

The clinical course of multiple sclerosis (MS) is variable and largely unpredictable pointing to an urgent need for markers to monitor disease activity and progression. Recent evidence revealed that tissue transglutaminase (TG2) is altered in patient-derived monocytes. We hypothesize that blood cell–derived TG2 messenger RNA (mRNA) can potentially be used as biomarker in patients with MS.

Methods

In peripheral blood mononuclear cells (PBMCs) from 151 healthy controls and 161 patients with MS, TG2 mRNA was measured and correlated with clinical and MRI parameters of disease activity (annualized relapse rate, gadolinium-enhanced lesions, and T2 lesion volume) and disease progression (Expanded Disability Status Scale [EDSS], normalized brain volume, and hypointense T1 lesion volume).

Results

PBMC-derived TG2 mRNA levels were significantly associated with disease progression, i.e., worsening of the EDSS over 2 years of follow-up, normalized brain volume, and normalized gray and white matter volume in the total MS patient group at baseline. Of these, in patients with relapsing-remitting MS, TG2 expression was significantly associated with worsening of the EDSS scores over 2 years of follow-up. In the patients with primary progressive (PP) MS, TG2 mRNA levels were significantly associated with EDSS, normalized brain volume, and normalized gray and white matter volume at baseline. In addition, TG2 mRNA associated with T1 hypointense lesion volume in the patients with PP MS at baseline.

Conclusion

PBMC-derived TG2 mRNA levels hold promise as biomarker for disease progression in patients with MS.

Classification of Evidence

This study provides Class II evidence that in patients with MS, PBMC-derived TG2 mRNA levels are associated with disease progression.

Transglutaminase 2 as a Marker for Inflammation and Therapeutic Target in Sepsis

Sepsis results in lethal organ malfunction due to dysregulated host response to infection, which is a condition with increasing prevalence worldwide. Transglutaminase 2 (TG2) is a crosslinking enzyme that forms a covalent bond between lysine and glutamine. TG2 plays important roles in diverse cellular processes, including extracellular matrix stabilization, cytoskeletal function, cell motility, adhesion, signal transduction, apoptosis, and cell survival. We have shown that the co-culture of Candida albicans and hepatocytes activates and induces the translocation of TG2 into the nucleus. In addition, the expression and activation of TG2 in liver macrophages was dramatically induced in the lipopolysaccharide-injected and cecal ligation puncture-operated mouse models of sepsis. Based on these findings and recently published research, we have reviewed the current understanding of the relationship between TG2 and sepsis. Following the genetic and pharmacological inhibition of TG2, we also assessed the evidence regarding the use of TG2 as a potential marker and therapeutic target in inflammation and sepsis.

Large-Scale Screening in General Population Children for Celiac Disease with a Multiplex Electrochemiluminescence (ECL) Assay

Background

Autoimmunity Screening for Kids (ASK) study was launched to screen general population children for type 1 diabetes (T1D) and celiac disease (CD).

Methods

A total of 23,319 children from general population were screened. A high throughput multiplex electrochemiluminescence (ECL) assay to screen multiautoantibodies in a single well was applied, parallel with a standard radiobinding assay (RBA). All children with any positive autoantibodies in screening were revisited within one month for confirmation and followed every 6 months.

Results

Among 23,319 children, 2.6% (606/23,319) of children were tested positive for TGA. Multiplex ECL assay detected more TGA (584/23,319) in the initial screening than RBA (490/23,319, p = 0.004) and was able to detect TGA earlier than RBA in a subset of children by 0.8 to 34.8 months. Prevalence of TGA by either ECL or RBA in children with islet autoantibodies was found significantly higher than overall prevalence in general population screened.

Conclusions

A multiplex ECL assay was more sensitive than standard RBA by identifying more TGA positivity and detecting TGA earlier in general population screening. It also provides a high efficient tool with its unique advantage of multiplexing measurements to screen for multiple autoimmune diseases simultaneously in general population.

The Role of Early Programming and Early Nutrition on the Development and Progression of Celiac Disease: A Review

Experimental and epidemiological evidence has shown that modifications of the intrauterine environment can have deleterious consequences for individuals, expressed as an increased risk of suffering non-communicable pathologies in adult life, which is known as the hypothesis of the early origin of diseases or fetal programming. On the other hand, changes in gene expression patterns through epigenetic modifications can be the basis for long-term maintenance of the effects of fetal programming. In this sense, epigenetics comprises the study of intrauterine disturbances, which develop diseases in the adult, including celiac disease (CD). In addition, early feeding practices could influence the risk of CD development, such as breastfeeding timing and duration and age of gluten introduction in the diet. Gluten acts as a trigger for CD in genetically predisposed subjects, although approximately 30% of the world population has HLA DQ2 or DQ8, the prevalence of the disease is only 1–3%. It is not known what factors act to modify the risk of disease in genetically at-risk subjects. Taking into account all these considerations, the aim of the current review is to elucidate the role of early programming and the effect of early nutrition on the development and progression of CD. It is logical that attention has been paid to gluten as a key element in preventing the disease. However, there is no strong evidence in favor of the protective factor of breastfeeding, timing of introduction of gluten during lactation, and the development of CD. Diet, genetic risk, microbiota, and environmental interaction are possible triggers of the change in tolerance to an immune response to gluten, but large-scale cohort studies are needed. Emerging scientific concepts, such as epigenetics, may help us establish the role of these factors.

Celiac Disease Screening for High-Risk Groups: Are We Doing It Right?

Celiac disease (CD) is an immune-mediated enteropathy triggered by dietary ingestion of gluten in genetically susceptible patients. CD is often diagnosed by a "case-finding" approach of symptomatic patients. In recent times, the diagnostic paradigm has shifted to investigate patients who may be asymptomatic, but are at high risk of developing CD due to shared genetic susceptibilities. These high-risk groups include first-degree relatives of CD patients and patients with Type 1 diabetes mellitus, autoimmune thyroid disease, Down's syndrome, and Turner syndrome. Moreover, CD is often diagnosed as the cause of iron deficiency anemia or unexplained chronic diarrhea. Although screening for CD with serological tests is not recommended for the general population, it should be considered in these special populations. In this review, we explore screening for CD among high-risk groups in light of recent research and development in the CD arena.

Food Allergies

Food allergy is 1 of the 4 manifestations of the "atopic march," along with eczema, allergic rhinitis, and asthma. Depending on the pathophysiologic immune mechanisms behind a food allergy, it can be classified as immunoglobulin E-mediated, non-immunoglobulin E-mediated, or mixed. The prevalence of food allergies has risen worldwide during the past few decades, becoming a significant global health concern. Patients experiencing food allergies and their caregivers are heavily burdened personally, socially, emotionally, and financially. The health-care system is also considerably affected. Pediatricians, as primary health-care providers, are often challenged with these patients, becoming the first-line for the recognition and management of food allergies. The purpose of this review is to provide a comprehensive summary of food allergies, including the most up-to-date information, recent guidelines, and recommendations.

Gluten Degrading Enzymes for Treatment of Celiac Disease

Celiac disease (CeD) affects about 1% of most world populations. It presents a wide spectrum of clinical manifestations, ranging from minor symptoms to mild or severe malabsorption, and it may be associated with a wide variety of autoimmune diseases. CeD is triggered and maintained by the ingestion of gluten proteins from wheat and related grains. Gluten peptides that resist gastrointestinal digestion are antigenically presented to gluten specific T cells in the intestinal mucosa via HLA-DQ2 or HLA-DQ8, the necessary genetic predisposition for CeD. To date, there is no effective or approved treatment for CeD other than a strict adherence to a gluten-free diet, which is difficult to maintain in professional or social environments. Moreover, many patients with CeD have active disease despite diet adherence due to a high sensitivity to traces of gluten. Therefore, safe pharmacological treatments that complement the gluten-free diet are urgently needed. Oral enzyme therapy, employing gluten-degrading enzymes, is a promising therapeutic approach. A prerequisite is that such enzymes are active under gastro-duodenal conditions, quickly neutralize the T cell activating gluten peptides and are safe for human consumption. Several enzymes including prolyl endopeptidases, cysteine proteases and subtilisins can cleave the human digestion-resistant gluten peptides in vitro and in vivo. Examples are several prolyl endopeptidases from bacterial sources, subtilisins from Rothia bacteria that are natural oral colonizers and synthetic enzymes with optimized gluten-degrading activities. Without exception, these enzymes must cleave the otherwise unusual glutamine and proline-rich domains characteristic of antigenic gluten peptides. Moreover, they should be stable and active in both the acidic environment of the stomach and under near neutral pH in the duodenum. This review focuses on those enzymes that have been characterized and evaluated for the treatment of CeD, discussing their origin and activities, their clinical evaluation and challenges for therapeutic application. Novel developments include strategies like enteric coating and genetic modification to increase enzyme stability in the digestive tract.

The Long-Term Safety and Quality of Life Effects of Oats in Dermatitis Herpetiformis

The treatment of choice for dermatitis herpetiformis (DH), a cutaneous manifestation of coeliac disease, is a life-long gluten-free diet (GFD). In a GFD, wheat, rye and barley should be strictly avoided, but the role of oats is more controversial. This study aimed to investigate the safety and long-term quality of life and health effects of oat consumption in 312 long-term treated DH patients. Baseline data were gathered from patient records and follow-up data from questionnaires or interviews, and validated questionnaires were used to assess quality of life. We found that altogether 256 patients (82%) were consuming oats as part of their GFD at the follow-up. Long-term follow-up data showed that there were no differences in the presence of long-term illnesses, coeliac disease complications or the usage of medication between those consuming and not consuming oats. However, oat consumers had a better quality of life and reported ongoing gastrointestinal symptoms less frequently (4% vs 19%, p = 0.004) at the follow-up than those not consuming oats. The study established that oats are safe for DH patients and in the long-term seem to improve the quality of life of DH patients.

Progress in the serology-based diagnosis and management of adult celiac disease

Introduction: This article provides a comprehensive overview of the development and application of serological tests used routinely in clinical practice for the diagnosis and management of adult celiac disease.Areas covered: We summarize existing scientific literature related to anti-endomyseal, anti-tissue transglutaminase, and anti-deamidated gliadin peptide antibodies and detail the current and potential future applications of these tests in celiac disease.Expert commentary: Current serological tests in celiac disease have some of the best performance characteristics among disease-specific tests. However, in adult celiac disease, current diagnostic algorithms still rely on duodenal biopsies to confirm the diagnosis. A 'biopsy avoidance strategy' has been implemented in pediatric celiac disease. Future high-quality studies will help inform on whether this approach can be implemented into adult gastroenterology services. It is envisaged that the next 5 years will see an increasing reliance on serology in the diagnosis of adult celiac disease.

Intestinal ex vivo organoid culture reveals altered programmed crypt stem cells in patients with celiac disease

The ex vivo generation of gastrointestinal organoids from crypt stem cells opens up the possibility of new research approaches investigating gastrointestinal diseases. We used this technology to study differences between healthy controls and patients with celiac disease (CD). We noticed distinct dissimilarities in the phenotypes of organoids between our study groups and found considerable variations in their gene expression. Extracellular matrix genes involved in epithelial-mesenchymal transition are expressed most differently. In addition, we demonstrated epigenetic modifications that might be responsible for the different organoid gene expression thus accounting for a deranged crypt/villus axis development in CD. The organoids have proven valuable to demonstrate fundamental differences in duodenal derived organoids between healthy controls and patients with CD and thus are a suitable tool to gain new insights in pathogenesis of CD.

Trend of Antitissue Transglutaminase Antibody Normalization in Children With Celiac Disease Started on Gluten-free Diet: A Comparative Study Between Chemiluminescence and ELISA Serum Assays

BACKGROUND

The aim of this study is to compare the performance of antitissue transglutaminase (atTG) chemiluminescence immunoassay (CLIA) with the standard enzyme-linked immunosorbent assay (ELISA) methods in monitoring celiac children after the start of gluten-free diet (GFD).

METHODS

Celiac children diagnosed between 2005 and 2016 at our centre were classified into 2 groups based on serum assay (ELISA vs CLIA) used for atTG monitoring, and were compared on percentage of decrease and time to normalization of atTG on GFD.

RESULTS

Among 260 included children, the rate of normalization of atTG levels at 30 months' follow-up was 86% and 70% in ELISA and CLIA group, respectively (P < 0.01). Median time to normalization was 11.7 and 14.7 months in ELISA and CLIA group respectively (P = 0.003). Marsh score at diagnosis was not associated with time to atTG normalization (P = 0.770), whereas older age at diagnosis and higher baseline atTG predicted longer time to atTG normalization (P = 0.01, P < 0.01).

CONCLUSIONS

The percentage and the time of the atTG normalization in celiac children on GFD should be interpreted according to the utilized assay: at 30 months' follow-up children tested by CLIA are less likely to normalize atTG levels compared to those tested by ELISA. Younger age at diagnosis and lower baseline atTG are predictors of earlier atTG normalization, regardless of the adopted assay.

Positive IgA against transglutaminase 2 in patients with distal radius and ankle fractures compared to community-based controls

BACKGROUND

Patients with celiac disease (CD), including adults with subclinical disease, have low bone mineral density (BMD), deteriorated bone microarchitecture and meta-analysis show an increased risk of fracture. Immunoglobulin A (IgA) against transglutaminase 2 (IgA TG2) is a highly reliable marker to detect CD.

MAIN OBJECTIVE

To explore the prevalence of positive IgA TG2 and CD in patients with distal radius and ankle fracture compared to community-based controls.

METHODS

Four hundred patients aged 40 years or above with distal fractures were included in a case-control study. About 197 controls were identified from the National Population Registry, those included had never suffered a fracture. BMD was measured, and comorbidities, medications, physical activity, smoking habits, body mass index (BMI) and nutritional factors were registered. Blood analysis to detect common causes of secondary osteoporosis was performed.

RESULTS

About 2.5% of the fracture patients had positive IgA TG2, compared to 1% in the control group. The odds ratio, adjusted for sex and age, of having positive IgA TG2 was 2.50 (95% CI 0.54-11.56).

CONCLUSIONS

There were no significantly increased odds of CD in adult patients with fractures compared to controls; however, results imply that positive IgA TG2 is more prevalent in fracture patients than in controls. This study indicates that universal screening for CD in fracture patients is not warranted, but supports current clinical practice in Norway to suspect and investigate for CD in patients with fracture, osteoporosis and other risk factors for CD.

Novel screening test for celiac disease using peptide functionalised gold nanoparticles

AIM

To develop a screening test for celiac disease based on the coating of gold nanoparticles with a peptide sequence derived from gliadin, the protein that triggers celiac disease.

METHODS

20 nm gold nanoparticles were first coated with NeutrAvidin. A long chain Polyethylene glycol (PEG) linker containing Maleimide at the Ω-end and Biotin group at the α-end was used to ensure peptide coating to the gold nanoparticles. The maleimide group with the thiol (-SH) side chain reacted with the cysteine amino acid in the peptide sequence and the biotinylated and PEGylated peptide was added to the NeutrAvidin coated gold nanoparticles. The peptide coated gold nanoparticles were then converted into a serological assay. We used the peptide functionalised gold nanoparticle-based assay on thirty patient serum samples in a blinded assessment and compared our results with the previously run serological and pathological tests on these patients.

RESULTS

A stable colloidal suspension of peptide coated gold nanoparticles was obtained without any aggregation. An absorbance peak shift as well as color change was caused by the aggregation of gold nanoparticles following the addition of anti-gliadin antibody to peptide coated nanoparticles at levels associated with celiac disease. The developed assay has been shown to detect anti-gliadin antibody not only in quantitatively spiked samples but also in a small-scale study on real non-hemolytic celiac disease patient’s samples.

CONCLUSION

The study demonstrates the potential of gold nanoparticle-peptide based approach to be adapted for developing a screening assay for celiac disease diagnosis. The assay could be a part of an exclusion based diagnostic strategy and prove particularly useful for testing high celiac disease risk populations.

Opening up about Tissue Transglutaminase: When Conformation Matters More than Enzymatic Activity

Tissue transglutaminase (tTG), also referred to as type 2 transglutaminase or Gα_h, can bind and hydrolyze GTP, as well as function as a protein crosslinking enzyme. tTG is widely expressed and can be detected both inside cells and in the extracellular space. In contrast to many enzymes, the active and inactive conformations of tTG are markedly different. The catalytically inactive form of tTG adopts a compact “closed-state” conformation, while the catalytically active form of the protein adopts an elongated “open-state” conformation. tTG has long been appreciated as an important player in numerous diseases, including celiac disease, neuronal degenerative diseases, and cancer, and its roles in these diseases often depend as much upon its conformation as its catalytic activity. While its ability to promote these diseases has been traditionally thought to be dependent on its protein crosslinking activity, more recent findings suggest that the conformational state tTG adopts is also important for mediating its effects. In particular, we and others have shown that the closed-state of tTG is important for promoting cell growth and survival, while maintaining tTG in the open-state is cytotoxic. In this review, we examine the two unique conformations of tTG and how they contribute to distinct biological processes. We will also describe how this information can be used to generate novel therapies to treat diseases, with a special focus on cancer.

Sex- and age-dependent effects of celiac disease on growth and weight gain in children with type 1 diabetes: Analysis of the type 1 diabetes Exchange Clinic Registry

BACKGROUND

Celiac disease (CD) is common in patients with type 1 diabetes (T1D) and effects of CD on growth in children with T1D remain unclear.

METHODS

We analyzed heights, weights, and body mass index (BMI) in 215 matched pediatric CD/control pairs in the T1D Exchange Clinic Registry. CD was defined by a clinic-reported diagnosis and positive celiac serology (n = 80) and/or positive small bowel biopsy (n = 135). Cases and controls were matched by age (mean: 14 years), diabetes duration (median: 7 years), sex (57% female), and clinic site. There were 5569 height/weight measurements.

RESULTS

Gluten was restricted for varying periods of time in 61% of females and 51% of males with CD. Females with CD were shorter than female controls at all ages (P = 0.01). Weight z-scores were initially lower in preschool females with CD but similar to controls by middle childhood. Males with CD were initially shorter but adult heights were similar. Height in both sexes and weight in males were lower in CD participants diagnosed at younger age. Growth in T1D children with biopsy-proven CD, 76% of them were gluten-restricted, was comparable to that of T1D controls.

CONCLUSION

Concurrent CD impairs linear growth in T1D females at all stages of development and in young T1D males. Young females with CD have lower weights, but both sexes have similar weights by middle childhood. Children younger at CD onset remain shorter throughout childhood; males younger at CD onset have persistently lower weights. Long-term gluten restriction may restore weight gain and linear growth in children with CD and T1D.

Daily Intake of Milk Powder and Risk of Celiac Disease in Early Childhood: A Nested Case-Control Study

Milk powder and gluten are common components in Swedish infants' diets. Whereas large intakes of gluten early in life increases the risk of celiac disease in genetically at-risk Swedish children, no study has yet evaluated if intake of milk powder by 2 years of age is associated with celiac disease. A 1-to-3 nested case-control study, comprised of 207 celiac disease children and 621 controls matched for sex, birth year, and HLA genotype, was performed on a birth cohort of HLA-DR3-DQ2 and/or DR4-DQ8-positive children. Subjects were screened annually for celiac disease using tissue transglutaminase autoantibodies (tTGA). Three-day food records estimated the mean intake of milk powder at ages 6 months, 9 months, 12 months, 18 months, and 24 months. Conditional logistic regression calculated odds ratios (OR) at last intake prior to seroconversion of tTGA positivity, and for each time-point respectively and adjusted for having a first-degree relative with celiac disease and gluten intake. Intake of milk powder prior to seroconversion of tTGA positivity was not associated with celiac disease (OR = 1.00; 95% CI = 0.99, 1.03; p = 0.763). In conclusion, intake of milk powder in early childhood is not associated with celiac disease in genetically susceptible children.

Review article: coeliac disease in later life must not be missed

BACKGROUND

The presenting symptoms of coeliac disease are often subtle and the diagnosis is frequently delayed or overlooked. Therefore, especially elderly patients may be denied the benefits conferred by gluten free diet which can be dramatically life-changing.

AIM

To review the occurrence, clinical features, diagnosis and management in coeliac patients detected later in life.

METHODS

To review manuscripts concerned with coeliac disease in the elderly and to derive subgroups of elderly people from publications on the disorder.

RESULTS

Approximately a quarter of all diagnoses are now made at the age of 60 years or more and a fifth at 65 years or over. About 4% are diagnosed at 80 years or above. Around 60% remain undetected, since their symptoms are often subtle: tiredness, indigestion, reduced appetite. Good compliance with gluten free diet, resolution of symptoms and improvement in laboratory indices can be achieved in over 90% of patients.

CONCLUSIONS

Coeliac disease not uncommonly presents for the first time in older patients and is an important diagnosis to make.

Using Serum IgE Antibodies to Predict Esophageal Eosinophilia in Children

OBJECTIVES

Symptoms of eosinophilic esophagitis are variable and can be nonspecific. Food-specific serum immunoglobulin E (IgE) antibodies are frequently found in patients with eosinophilic esophagitis and are obtained using a widely available blood test. Our objective was to evaluate the ability of food-specific IgE antibodies to predict the presence of esophageal eosinophilia.

METHODS

We reviewed 144 medical records for pediatric patients having esophageal biopsy and serum analysis for IgE antibodies to food (exploratory group). We performed logistic regression using sex and number of positive food-specific IgE tests to develop a model that predicts ≥15 eosinophils/high-power field (hpf) in the esophagus. We tested the model using 142 additional patients (validation group).

RESULTS

The probability of having ≥15 eosinophils/hpf in the esophagus was higher in boys and increased with the number of positive food-specific IgE tests from 12% (95% confidence interval 4.8-26) in girls with 0 foods positive to 86% (95% confidence interval 71-94) for boys with 4 or 5 foods positive. The statistical model using sex and number of positive IgE tests to predict patients having ≥15 eosinophils/hpf showed acceptable discriminative ability (area under the receiver operating characteristic curve 0.80). The performance metrics for the model to predict ≥15 eosinophils/hpf in the validation group were similar (area under the receiver operating characteristic curve 0.75).

CONCLUSIONS

Requiring only a blood test and a simple algorithm, analysis for IgE antibodies to food may expedite an esophagogastroduodenoscopy and decrease delays in the diagnosis and treatment of patients with nonspecific gastrointestinal symptoms who have increased eosinophils in the esophagus.

Undetectable negative tissue transglutaminase IgA antibodies predict mucosal healing in treated coeliac disease patients

BACKGROUND

Tissue transglutaminase (tTG) immunoglobulin A (IgA) testing is a sensitive adjunct to the diagnosis of coeliac disease. The threshold for positivity was developed for diagnosis, with negative results reported as below the reference value (<4 U/mL).

AIM

To investigate if an undetectable (tTG IgA<1.2 U/mL) is more predictive of healing compared to patients with negative but detectable serology (1.2-3.9 U/mL).

METHODS

We performed a retrospective study of 402 treated coeliac disease patients seen at the Mayo Clinic with negative tTG IgA values drawn within 1 month of duodenal biopsy between January 2009 and December 2015. The Corazza-Villanacci score was used to assess mucosal healing. The presence of gastrointestinal symptoms was also collected. Logistic regression was used to assess the relationship of clinical variables with a normal biopsy.

RESULTS

Patients with undetectable titres more frequently had normal duodenal histology compared to patients with detectable tTG IgA levels (117/240 vs. 53/162; OR=1.96; 1.292, 2.961). Asymptomatic patients more frequently had normal duodenum as compared to symptomatic patients (88/163 vs. 82/239; OR=2.25; CI: 1.494, 3.377). Patients with undetectable serology and on a gluten-free diet for ≥2 years were more likely to have no villous atrophy compared to patients with detectable serology (148/192 vs. 55/88; OR=2.02; CI: 1.17, 3.49).

CONCLUSION

In subjects recovering from coeliac disease with negative tTG IgA serology, an undetectable titre is associated with normal histology on follow-up biopsy.

Celiac disease: from etiological factors to evolving diagnostic approaches

Celiac disease has advanced from a medical rarity to a highly prevalent disorder. Patients with the disease show varying degrees of chronic inflammation within the small intestine due to an aberrant immune response to the digestion of gliadin found in wheat. As a result, cytokines and antibodies are produced in celiac patients that can be used as specific biomarkers for developing diagnostic tests. This review paper describes celiac disease in terms of its etiological cause, pathological effects, current diagnostic tests based on mucosal biopsy, and the genetic basis for the disease. In addition, it discusses the use of gliadin-induced cytokines, antibodies and autoantibodies as a diagnostic tool for celiac disease. Despite good initial results in terms of sensitivity and specificity, when these immunological tests were used on a large scale, even in combination with genetic testing, the results showed lower predictive value. This review addresses that issue and ends with an outlook on future work required to develop diagnostic tests with greater accuracy in predicting celiac disease in the general public, thus avoiding the need for endoscopy and mucosal biopsy.

New Insights into the Pathogenesis of Celiac Disease

Celiac disease (CD) is an autoimmune and multisystem gluten-related disorder that causes symptoms involving the gastrointestinal tract and other organs. Pathogenesis of CD is only partially known. It had been established that ingestion of gluten proteins present in wheat and other cereals are necessary for the disease and develops in individuals genetically predisposed carrying the DQ2 or DQ8 human leukocyte antigen haplotypes. In this review, we had pay specific attention on the last discoveries regarding the three cellular components mainly involved in the development and maintenance of CD: T-cells, B-cells, and microbioma. All of them had been showed critical for the interaction between inflammatory immune response and gluten peptides. Although the mechanisms of interaction among overall these components are not yet fully understood, recent proteomics and molecular studies had shed some lights in the pathogenic role of tissue transglutaminase 2 in CD and in the alteration of the intestinal barrier function induced by host microbiota.

Antitissue Transglutaminase Normalization Postdiagnosis in Children With Celiac Disease

OBJECTIVES

Limited pediatric data exist examining the trend and predictors of antitissue transglutaminase (atTG) normalization over time in children with celiac disease (CD). We aimed to evaluate time to normalization of atTG in children after CD diagnosis, and to assess for independent predictors affecting this duration.

METHODS

A retrospective chart review was completed in pediatric patients with CD diagnosed from 2007 to 2014 at the Stollery Children's Hospital Celiac Clinic (Edmonton, Alberta, Canada). The clinical predictors assessed for impact on time to atTG normalization were initial atTG, Marsh score at diagnosis, gluten-free diet compliance (GFDC), age at diagnosis, sex, ethnicity, medical comorbidities, and family history of CD. Kaplan-Meier survival analysis was completed to assess time to atTG normalization, and Cox regression to assess for independent predictors of this time.

RESULTS

A total of 487 patients met inclusion criteria. Approximately 80.5% of patients normalized atTG levels. Median normalization time was 407 days for all patients (95% confidence interval [CI: 361-453]), and 364 days for gluten-free diet compliant patients (95% CI [335-393]). Type 1 diabetes mellitus (T1DM) patients took significantly longer to normalize at 1204 days (95% CI [199-2209], P < 0.001). Cox regression demonstrated T1DM (hazard ratio = 0.36 [0.24-0.55], P < 0.001) and higher baseline atTG (hazard ratio = 0.52 [0.43-0.63], P < 0.001) were significant predictors of longer atTG normalization time. GFDC was a significant predictor of earlier normalization (OR = 13.91 [7.86-24.62], P < 0.001).

CONCLUSIONS

GFDC and lower atTG at diagnosis are predictors of earlier normalization. Patients with T1DM are less likely to normalize atTG levels, with longer normalization time. Additional research and education for higher-risk populations are needed.

Next-Generation Autoantibody Testing by Combination of Screening and Confirmation-the CytoBead® Technology

Occurrence of autoantibodies (autoAbs) is a hallmark of autoimmune diseases, and the analysis thereof is an essential part in the diagnosis of organ-specific autoimmune and systemic autoimmune rheumatic diseases (SARD), especially connective tissue diseases (CTDs). Due to the appearance of autoAb profiles in SARD patients and the complexity of the corresponding serological diagnosis, different diagnostic strategies have been suggested for appropriate autoAb testing. Thus, evolving assay techniques and the continuous discovery of novel autoantigens have greatly influenced the development of these strategies. Antinuclear antibody (ANA) analysis by indirect immunofluorescence (IIF) on tissue and later cellular substrates was one of the first tests introduced into clinical routine and is still an indispensable tool for CTD serology. Thus, screening for ANA by IIF is recommended to be followed by confirmatory testing of positive findings employing different assay techniques. Given the continuous growth in the demand for autoAb testing, IIF has been challenged as the standard method for ANA and other autoAb analyses due to lacking automation, standardization, modern data management, and human bias in IIF pattern interpretation. To address these limitations of autoAb testing, the CytoBead® technique has been introduced recently which enables automated interpretation of cell-based IIF and quantitative autoAb multiplexing by addressable microbead immunoassays in one reaction environment. Thus, autoAb screening and confirmatory testing can be combined for the first time. The present review discusses the history of autoAb assay techniques in this context and gives an overview and outlook of the recent progress in emerging technologies.

High prevalence of organ specific autoantibodies in Indian type 1 diabetic patients

BACKGROUND

Type 1 diabetes (T1D) is frequently associated with other autoimmune conditions such as autoimmune thyroiditis, coeliac disease (CD) and Addison's disease. There are sparse data on the prevalence of antibodies against these conditions in Indian patients with T1D. This study aims to evaluate prevalence of these T1D associated autoantibodies in Indian patients.

METHODS

Two hundred and fifty-eight patients with T1D were recruited from the Bangalore Diabetes Hospital and the Vydehi Institute of Medical Sciences and Research Centre (VIMS) for the study. Participants diagnosed with diabetes before the age of 18 years, as per the American Diabetes Association (ADA) criteria, and who were classified as T1D based on clinical grounds were recruited for the study. Anti-thyroid peroxidase antibody (TPO) and IgA tissue transglutaminase antibody (tTG) were estimated in all the patients. 21-Hydroxylase antibody (21-OHAb) were estimated in 170 patients. All assays were done by commercial immunoassay. Eighty-eight unrelated age-matched healthy controls were chosen for comparison.

RESULTS

The mean age of T1D patients was 14.33 years. The mean duration of diabetes was 4.88 years. Anti-TPO was positive in 43 (16.7%) patients with T1D as compared to 3 (3.4%) in controls. IgA tTG was positive in 12 (4.65%) patients with T1D and was absent in controls. 21-OHAb was positive in two (1.1%) patients with T1D and was absent in controls. Both patients who had positive 21-OHab had the other two antibodies. Five patients had positive anti-TPO and IgA-tTG antibodies.

CONCLUSIONS

Anti-TPO antibody was the most prevalent antibody in patients with T1D. Anti-TPO and IgA-tTG antibodies were significantly higher than in the control population. Further studies will be required to assess the clinical significance of these positive antibodies.

Development of autoantibodies precedes clinical manifestations of autoimmune diseases: A comprehensive review

The etiology of autoimmune diseases is due to a combination of genetic predisposition and environmental factors that alter the expression of immune regulatory genes through various mechanisms including epigenetics. Both humoral and cellular elements of the adaptive immune system play a role in the pathogenesis of autoimmune diseases and the presence of autoantibodies have been detected in most but not all autoimmune diseases before the appearance of clinical symptoms. In some cases, the presence or levels of these autoantibodies portends not only the risk of developing a corresponding autoimmune disease, but occasionally the severity as well. This observation is intriguing because it suggests that we can, to some degree, predict who may or may not develop autoimmune diseases. However, the role of autoantibodies in the pathogenesis of autoimmune diseases, whether they actually affect disease progression or are merely an epiphenomenon is still not completely clear in many autoimmune diseases. Because of these gaps in our knowledge, the ability to accurately predict a future autoimmune disease can only be considered a relative risk factor. Importantly, it raises the critical question of defining other events that may drive a patient from a preclinical to a clinical phase of disease.

Omitting duodenal biopsy in children with suspected celiac disease and extra-intestinal symptoms

BACKGROUND

The aim of our study is to evaluate if in children with highly positive serology and HLA-DQ2/DQ8 (triple test, TT) and only extra-intestinal symptoms, it is possible to omit performing an intestinal biopsy for celiac disease (CD) diagnosis, as suggested by the new European Society for Pediatric Gastroenterology, Hepatology and Nutrition ESPGHAN guidelines.

METHODS

In this retrospective study a total of 105 patients, suspected of having CD because of extra-intestinal symptoms and showing serum tissue transglutaminase antibody (anti-tTG) and anti-endomysial antibody (EMA) measurements and HLA genotyping, were considered for the final analysis (33 boys and 72 girls; age range 1.5-17.6 years).

RESULTS

Histological findings confirmed diagnosis of CD in 97 (92.4%) patients. Forty-one patients (39%) showed anti-tTG >10 times normal values, positive EMA and positive HLA-DQ2/DQ8 (positive TT). All of them had a diagnosis of CD, therefore there were no false positive cases. Sixty-four patients were negative for the TT. In eight cases, CD was ruled out and these were considered true negative cases. In the remaining 56 negative TT patients, intestinal biopsy confirmed CD diagnosis and they were considered false negatives. Based on these results, specificity for the TT was 100% and sensitivity was 42.3%.

CONCLUSIONS

On the basis of the present study, diagnosis of CD can be reliably performed without a duodenal biopsy in children with only extra-intestinal symptoms.

[Celiac disease : Pathogenesis, clinics, epidemiology, diagnostics, therapy]

Celiac disease is induced by the consumption of gluten containing cereals (wheat, spelt, barley, rye). With a prevalence of ~ 1 %, it is the most common non-infectious chronic inflammatory intestinal disease worldwide. It manifests in all age groups, either classically with abdominal pain, diarrhoea and growth failure or weight loss, more commonly with indirect consequences of malabsorption, such as anaemia and osteoporosis, or with associated autoimmune diseases like type 1 diabetes, autoimmune thyroiditis or dermatitis herpetiformis. The pathogenesis of celiac disease is well explored. Gluten, the cereal storage protein, is not completely digested and reaches the intestinal mucosa where it activates inflammatory T cells, which cause atrophy of the resorptive villi. This T‑cell activation requires a genetic predisposition (the molecules HLA-DQ2 or -DQ8 on antigen-presenting immune cells). Moreover, the enzyme tissue transglutaminase (TG2) which is released in the mucosa increases the immunogenicity of the gluten peptides by a deamidation reaction. The test for serum antibodies to the autoantigen TG2 is one of the best diagnostic markers in medicine, which in combination with endoscopically obtained biopsies, secures the diagnosis of celiac disease. Despite these tools celiac disease is severely underdiagnosed, with 80-90 % of those affected being undetected. The untreated condition can lead to grave complications. These include the consequences of malabsorption, cancers (especially intestinal T‑cell lymphoma), and likely also the promotion of autoimmune diseases. The therapy of celiac disease, a strict gluten-free diet, is difficult to maintain and not always effective. Alternative, supporting pharmacological therapies are urgently needed and are currently in development.