HLA-DQ and risk gradient for celiac disease

Homozygous HLA-DQB1*06:02 combined with T-cell receptor alpha polymorphism results in narcolepsy onset - A familial case report

Narcolepsy is a life-long neurological disorder with well-established genetic risk factors. Human leukocyte antigen-DQB1*06:02 remains the strongest genetic predeterminant; however, polymorphisms in genes encoding the T-cell receptor alpha chain are also strongly linked. This case report shows the inheritance pathway of these genetic markers contributing to narcolepsy onset in a 17-year-old female.

Saliva direct PCR protocol for HLA-DQB1*02 genotyping

Celiac disease (CD) is an immune disorder, that is triggered by gluten ingestion in genetically predisposed individuals. The HLA-DQB1*02 allele is the main predisposing genetic factor and a candidate for first-line genotyping screening. We designed and validated a simple, DNA purification-free PCR protocol directly from crude saliva, enabling the detection of the DQB1*02 allele. This assay also distinguishes homozygous from heterozygous carriers. We propose this method for use in mass screening and/or epidemiological studies.

Performance assessment of a new G12/A1 antibody-based rapid ELISA using commercially available and gluten-spiked food samples

OBJECTIVE

Food products with <20 mg/kg gluten can be labeled 'gluten-free' according to international regulations. Several antibodies-based ELISAs have been develop to track gluten traces in food products. Among them, R5 and G12 antibody-based ELISAs are the frequently used methods. However, these antibodies have certain limitations. We evaluated the accuracy of G12/A1 antibody-based 'Glutentox ELISA Rapid G12' and compared the results with the current reference method i.e., R5 antibody-based 'Ridascreen R5 ELISA'.

METHODS

In the first step, the performance of Glutentox ELISA Rapid G12 kit was inspected by determination of the threshold value i.e., > or <20 mg/kg gluten in different food products. In the second step, quantification accuracy was assessed by quantification of gluten in gluten-free food products spiked with gliadin reference material.

RESULTS

In total 47 food products (naturally and labeled gluten-free, and food with traces of gluten) were included. Of them, 29 products were quantified with <20 mg/kg, and 18 with a low level of gluten by both the kits. Six out of 29 gluten-free products were used for the recovery test at different spike levels. Gluten concentration and mean recovery rates of individual kits showed consistency.

CONCLUSION

GlutenTox Rapid G12 ELISA could be an appropriate choice for detecting gluten in food products but needs more in-house validation and collaborative tests.

Total serum IgA levels and HLA-DQB1*02:01 allelic status

Immunoglobulin A Deficiency (IgAD) is the most common primary immunodeficiency and is significantly associated with Celiac Disease (CD), which recognizes a specific background of human leukocyte antigens (HLA) predisposition (including HLA-DQB1*02:01 allele). A number of studies investigated the role of HLA in IgAD etiopathogenesis: HLA-DQB1*02 alleles are included in the main haplotypes linked to this primary immunodeficiency. In this preliminary study, we investigated the potential impact of HLA-DQB1*02:01 allelic status on total serum IgA levels: 108 serum samples from the bone marrow donors' registry were analyzed for total IgA concentration with respect to the HLA-DQB1*02:01 status. Although total serum IgA levels between HLA-DQB1*02:01 carriers and HLA-DQB1*02:01 negative donors were not different, we observed a statistically significant difference (p=0.0118) in total serum IgA levels among donors with low IgA concentration (<80mg/dL) in the sub-analysis between HLA-DQB1*02:01 positive group (including both homozygous and heterozygous carriers) compared to HLA-DQB1*02:01 negative donors. Our results might suggest a role of HLA-DQB1*02:01 allelic variant in the determination of total serum IgA levels, at least in patients affected with IgA deficiency and/or otherwise predisposed to it; however, larger and more standardized studies are needed to confirm this speculation.

UK NEQAS and BSHI guideline: Laboratory testing and clinical interpretation of HLA genotyping results supporting the diagnosis of coeliac disease

Coeliac disease is a common immune-mediated inflammatory disorder caused by dietary gluten in genetically susceptible individuals. While the diagnosis of coeliac disease is based on serological and histological criteria, HLA-DQ genotyping can be useful, especially in excluding the diagnosis in patients who do not carry the relevant DQ heterodimers: DQA1*05 DQB1*02, DQB1*03:02 or DQA1*02 DQB1*02 (commonly referred to as DQ2.5, DQ8 and DQ2.2, respectively). External quality assessment results for HLA genotyping in coeliac disease have revealed concerning errors in HLA genotyping, reporting and clinical interpretation. In response, these guidelines have been developed as an evidence-based approach to guide laboratories undertaking HLA genotyping for coeliac disease and provide recommendations for reports to standardise and improve the communication of results.

The Combination of Gold and Silver Food Nanoparticles with Gluten Peptides Alters the Autophagic Pathway in Intestinal Crypt-like Cells

Metallic nanoparticles (mNPs) are widely used as food additives and can interact with gliadin triggering an immune response, but evaluation of the effects on crypts, hypertrophic in celiac subjects, is still lacking. This study evaluated the effects of gold and silver mNPs in combination with gliadin on crypt-like cells (HIEC-6). Transmission electron microscopy (TEM) was used to evaluate gliadin-mNP aggregates in cells. Western blot and immunofluorescence analysis assessed autophagy-related molecule levels (p62, LC3, beclin-1, EGFR). Lysosome functionality was tested with acridine orange (AO) and Magic Red assays. TEM identified an increase in autophagic vacuoles after exposure to gliadin + mNPs, as also detected by significant increments in LC3-II and p62 expression. Immunofluorescence confirmed the presence of mature autophagosomes, showing LC3 and p62 colocalization, indicating an altered autophagic flux, further assessed with EGFR degradation, AO and Magic Red assays. The results showed a significant reduction in lysosomal enzyme activity and a modest reduction in acidity. Thus, gliadin + mNPs can block the autophagic flux inducing a lysosomal defect. The alteration of this pathway, essential for cell function, can lead to cell damage and death. The potential effects of this copresence in food should be further characterized to avoid a negative impact on celiac disease subjects.

Unveiling the Etiopathogenic Spectrum of Hypophysitis: A Narrative Review

Hypophysitis, a rare inflammatory disorder of the pituitary gland, has seen an uptick in reported cases in recent years. Our objective is to summarize the most recent research on the etiopathogenesis, molecular mechanisms, and genetics of both primary and secondary hypophysitis. Primary autoimmune hypophysitis (PAH): During the acute phase of the disease, the pituitary gland in enlarged due to the infiltration of T and B lymphocytes. The chronic phase is characterized by progressive and irreversible pituitary atrophy. APA may play a role in the management, diagnosis, and prognosis of PAH. Specific autoantibodies such as anti-GH, anti-PIT-1, and anti-T-PIT have been found in patients with hypophysitis and hypopituitarism. A recent study suggested that a mechanism of escaping clonal deletion and mounting an immune response against self antigens can explain the unusual nature of the immune response observed in PAH patients. A cytokine array shows the presence of gamma-interferon and interleukin-17. Patients carrying mutations in the PIT1 or PROP1 genes may present PAH. Individuals carrying the HLA DQ8 haplotype are four times more likely to develop PAH. Immune checkpoint inhibitors induce hypophysitis (IIHs): IIHs is an increasingly frequent toxicity of in patients on treatment with inhibitors targeting cytotoxic T-lymphocyte antigen 4 (CTLA-4) and programmed cell death-1 (PD-1). ICIs inhibit the CTLA-4 pathway, leading to overactivation of T lymphocytes. The binding of PD-1/PD-L1 suppresses the activity of T cells, promotes the conversion of T-helpers into T-regulatory cells, and activates pro-survival signaling pathways in cancer cells. Cytokines play a crucial role in IIHs. B-cell infiltration has been observed in IIHs, suggesting that antibody-mediated pituitary injury may contribute. Genetic polymorphisms of CTLA-4 and PD-1 genes can increase the risk of IIHs. HLA alleles may also be involved in the onset of IIHs; this HLA association presents a possible alternative mechanistic hypothesis. IIHs may also be linked to a paraneoplastic syndrome triggered by ectopic expression of pituitary specific antigens. SARS-CoV-2-related hypophysitis: Recently, the literature has reported occurrences of hypophysitis associated with the SARS-CoV-2 virus; long COVID-19 may also present as infundibulo-neuro-hypophysitis. The virus enters the central nervous system because of its distinct interaction with angiotensin-converting enzyme receptors via spike proteins binding the capillary endothelium, and it directly damages the pituitary cells. The effect of SARS-CoV-2 can occur indirectly through inflammation and the release of cytokines. The exact mechanism remains ambiguous. The available data on endocrine complications associated with the SARS-CoV-2 vaccine are scant. Nonetheless, isolated cases of hypophysitis have been documented. Treatment of hypophysitis: Glucocorticoids are the cornerstone in managing primary hypophysitis, given their targeted action on inflammation. A better understanding of the etiopathogenesis and molecular mechanism of hypophysitis can lead to more effective and personalized treatment strategies.

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.

"Geographical distribution of risk genotypes in pediatric patients with celiac disease in Spain"

Celiac disease is strongly associated with HLA DQ, specifically with haplotypes. DRB1*03-DQA1*05:01/DQB1*02:01 (DQ2.5),DRB1*07-DQA1*02:01/DQB1*02:02 (DQ2.2), DRB1*11-DQA1*05:05/DQB1*03:01 (DQ7.5), and DRB1*04-DQA1*03:01/DQB1*03:02 (DQ8). The distribution of these risk haplotypes in patients with celiac disease is different in the geographical areas investigated. A high frequency of DRB1*07- DQA1*02:01/DQB1*02:02 (DQ2.2) and DRB1*11-DQA1*05:05/DQB1*03:01 (DQ7.5), has been described in Southern Europe. We analyzed 2102 confirmed CD cases with information on both DQB1* alelles and their distribution by geographical area in Spain. According to the presence of this haplotype in one or two chromosomes, the genotype is classified in: DQ2 homozygous, DQ2 heterozygous (cis or trans), DQ8 homozygous, DQ8/DQ2.5, DQ 2.2 homozygous and genotype known as "half DQ2". Two different patterns of risks related to CD were identified. In the Basque Country and Navarre, the Mediterranean Area (Aragon, Catalonia, Valencia, Balearic Islands, and Murcia), the South of Spain (Andalucía and Extremadura), and the Canary Islands, higher frequency of DQ2.5 trans, and more than 80% of DQ2.5/DQ2.2 homozygosis were described. The Cantabrian Coast (Cantabria, Asturias, and Galicia) and Central Areas (Castilla-León and Castilla-La Mancha) showed a higher percentage of DQ2.5/DQ2.5 homozygosis and a lower DQ2.5 in trans frequency, as in Northern Europe. Madrid has an intermediate model between the two described above. 17 cases (0.8%) did not carry any CD risk haplotypes.

Celiac Disease Genetics, Pathogenesis, and Standard Therapy for Japanese Patients

Celiac disease is an autoimmune disease primarily affecting the small intestine that is caused by the ingestion of gluten in genetically susceptible individuals. The development of celiac disease is based on a complex immune response to gluten proteins. The global average prevalence in the general population is about 1%. In recent years, it has become clear that celiac disease is not less common in Asian countries than in Western countries but often remains undiagnosed. Although the number of patients with celiac disease in Asia is expected to increase with improving disease recognition and advances in diagnostic techniques, there remain few reports of celiac disease in the Far East region of Asia, especially in Japan. In this paper, we outline the epidemiology, diagnosis, and treatment of celiac disease. In addition, we summarize the reported Japanese cases of celiac disease with an overview in Japan.

HLA-DQ genotype distribution and risk evaluation of celiac disease in Northwest China

BACKGROUND

Celiac disease (CD) is an autoimmune small bowel disease. Genetic susceptibility for CD is mainly determined by the human leukocyte antigen (HLA)-DQ haplotypes. The risk of CD conferred by HLA genotypes varies geographically and across populations, however, this has not yet been documented in Chinese patients with CD.

AIMS

To investigate the distribution of HLA-DQ and the related risks of CD development in Northwest China.

METHODS

A total of 75 CD patients and 300 healthy individuals were genotyped for HLA-DQ using the Illumina NextSeq, and the relative risks of the different genotypes were evaluated.

RESULTS

In total, 68.00% of CD patients and 21.00% of controls carried HLA-DQ2.5 heterodimers (p < 0.001). We identified four CD risk gradients. Individuals carrying a double dose of DQB1*02 had the highest risk of developing CD (1:16); however, with heterozygosis (DQB1*02:02/DQB1*02:01) having the highest risk (1:9). HLA-DQ2.5 individuals with a single copy of HLA-DQB1*02, in either the cis or trans configuration, were at a medium risk (1:38). Non-DQ2.5 carriers of DQ8 or DQ2.2 were at low risk, while only carriers of DQ7.5 or DQX.5 were at very low risk. Patients with the HLA-DQ2.5 genotype had more severe mucosal damage compared with the HLA-DQ2.5 genotype negative CD patients (70.59% vs. 41.67%, p = 0.016).

CONCLUSION

Genetic susceptibility to CD is highly prevalent in the Northwest Chinese population and the highest risk of developing CD was associated with the DQ2.5/DQ2.2 genotype. The DQ2.5 allele is involved in the severity of mucosal injury.

Guidelines of the Italian societies of gastroenterology on the diagnosis and management of coeliac disease and dermatitis herpetiformis

INTRODUCTION

Coeliac disease and dermatitis herpetiformis are immune-mediated diseases triggered by the consumption of gluten in genetically predisposed individuals. These guidelines were developed to provide general practitioners, paediatricians, gastroenterologists, and other clinicians with an overview on the diagnosis, management and follow-up of coeliac patients and those with dermatitis herpetiformis.

METHODS

Guidelines were developed by the Italian Societies of Gastroenterology. Following a systematic literature review, the Grading of Recommendations Assessment, Development and Evaluation methodology was used to assess the certainty of the evidence. Statements and recommendations were developed by working groups consisting of gastroenterologists and a paediatrician with expertise in this field.

RESULTS

These guidelines provide a practical guidance for the diagnosis, management and follow-up of coeliac patients and dermatitis herpetiformis in children and adults, both in primary care and in specialist settings. We developed four sections on diagnosis, gluten-free diet, follow-up and risk of complications in adults, one section focused on diagnosis and follow-up in children and one on the diagnosis and management of dermatitis herpetiformis.

CONCLUSIONS

These guidelines may support clinicians to improve the diagnosis and management of patients with coeliac disease.

Prevalence of haplotype DQ2/DQ8 and celiac disease in children with type 1 diabetes

Type 1 diabetes (T1D) and celiac disease (CD) coexist very often. Identification of the human leukocyte antigen (HLA) DQ2/DQ8 can confirm the genetic predisposition to CD. Negative result of this test allows to exclude CD with a high probability. It was suggested that in individuals with higher risk of CD, including T1D patients, the implementation of genetic testing should reduce the number of patients requiring systematic immunological screening. The aim of this study was to analyze the prevalence of different haplotypes predisposing to CD in children and adolescents with previously diagnosed T1D.

MATERIAL AND METHODS

A retrospective analysis was performed on 166 T1D children (91 girls) in whom HLA DQ2/DQ8 alleles were tested. In 9.6% CD was also diagnosed.

RESULTS

In 12.7% both HLA DQ2/DQ8 were negative. In 87.3% patients HLA DQ2 and/or DQ8 was positive, including 27.7% patients with both haplotypes DQ2.5 and DQ8 positive. In all CD patients the disease predisposing alleles were positive, while none of the HLA DQ2/DQ8 negative children were diagnosed with CD.

CONCLUSIONS

The prevalence of HLA DQ2.5 and the HLA DQ2.5 / HLA DQ8 configuration is higher in patients with T1D, and CD compared to children with T1D alone. The combination of HLA DQ2 and HLA DQ8 most significantly increases the risk of developing CD. The group of HLA DQ2/DQ8 negative patients with improbable CD diagnosis, is relatively small. Most of T1D patients HLA DQ2/DQ8 positive need further regular antibody assessment. In patients with T1D, who are at high risk of developing CD, genetic testing may be considered to select those who require further systematic serological evaluation. Due to its retrospective nature, the study was not registered in the database of clinical trials and the Clinical trial registration number is not available.

Distribution of celiac disease predisposing genes HLA-DQ2 and HLA-DQ8 in the native population of southern India

BACKGROUND

Celiac disease (CD) is an intestinal inflammatory condition caused by the ingestion of gluten peptides in wheat and related grains in individuals carrying HLA-DQ2 and/or HLA-DQ8 genes. In comparison to HLA-DQ8, a higher HLA-DQ2 prevalence is reported in European population where wheat has been the staple food for thousands of years. In non-European population, this pattern of HLA-DQ CD-predisposing gene distribution has not always been found. The aim of this study was to evaluate the HLA-DQ2 and HLA-DQ8 distribution in the native low-gluten consuming southern Indian population.

METHODS

Overall, 211 dried blood spots (DBS) were collected from native southern Indian individuals. HLA-DQ characterization and the determination of homozygous/heterozygous status were performed using commercially available HLA-DQ typing kits.

RESULTS

Of 211 collected DBS, 88 (42%, 95% CI: 36-48) were positive for HLA-DQ2 and/or HLA-DQ8 heterodimers. Overall, 40 (19%, 95% CI: 14-24) samples typed positive for HLA-DQ2 and 48 (23%, 95% CI: 18-28) typed positive for HLA-DQ8 genotypes. Of 40 HLA-DQ2-positive individuals, only one subject tested homozygous for the DQB1*02 allele.

CONCLUSIONS

In the southern Indian native general population, the prevalence of HLA-DQ8 is higher in comparison to HLA-DQ2 prevalence. This finding could be related to the delayed introduction of wheat in the diet of the southern Indian population.

The Role of HLA in the Association between IgA Deficiency and Celiac Disease

Selective IgA deficiency (SIgAD) is the most frequent primary immune defect. Since SIgAD is not characterized by relevant infectious issues in most cases, it is often diagnosed during the diagnostic work up of several and different autoimmune disorders, which are associated with this primary immune defect. The genetic background of SIgAD is complex and three HLA haplotypes resulted to be more frequently associated with it; in detail, two of them include HLA-DQB1^∗02 allelic variants, which are essential predisposing factors to develop Celiac Disease (CD). Here, we discuss the evidence regarding the role of HLA in the etiopathogenesis of SIgAD and its association with CD. Actually, the HLA region seems to play a modest role in the genetic predisposition to SIgAD and we may speculate that the association with the HLA-DQB1^∗02 alleles (or haplotypes including them) could derive from its link with CD. Indeed, SIgAD and some related immunological alterations are likely to predispose to several autoimmune diseases (with and despite different HLA backgrounds), including CD, which is relatively common and directly associated with the HLA-DQB1^∗02 allelic variants coding the DQ2 heterodimer. Further and specific studies are needed to make final conclusions in this regard.

The Role of the Gluten-Free Diet in the Management of Seronegative Enteropathy

The differential diagnosis and treatment of seronegative enteropathy, also termed seronegative villous atrophy (SNVA), is a clinical challenge. Although seronegative coeliac disease (CD) is a frequent cause of SNVA, the aetiology can include immune-mediated, inflammatory, infectious, and drug-related forms. As a misdiagnosis of SNVA can result in patients being unnecessarily placed on a lifelong strict gluten-free diet or even given incorrect immunosuppressive therapy, the aim of this paper is to provide an evidence-based and practical approach for the workup and management of SNVA.

Gluten-Free Diet Reduces Symptoms, Particularly Diarrhea, in Patients With Irritable Bowel Syndrome and Antigliadin IgG

BACKGROUND & AIMS

Many patients with irritable bowel syndrome (IBS) perceive that their symptoms are triggered by wheat-containing foods. We assessed symptoms and gastrointestinal transit before and after a gluten-free diet (GFD) in unselected patients with IBS and investigated biomarkers associated with symptoms.

METHODS

We performed a prospective study of 50 patients with IBS (ROME III, all subtypes), with and without serologic reactivity to gluten (antigliadin IgG and IgA), and 25 healthy subjects (controls) at a university hospital in Hamilton, Ontario, Canada, between 2012 and 2016. Gastrointestinal transit, gut symptoms, anxiety, depression, somatization, dietary habits, and microbiota composition were studied before and after 4 weeks of a GFD. HLA-DQ2/DQ8 status was determined. GFD compliance was assessed by a dietitian and by measuring gluten peptides in stool.

RESULTS

There was no difference in symptoms among patients at baseline, but after the GFD, patients with antigliadin IgG and IgA reported less diarrhea than patients without these antibodies (P = .03). Compared with baseline, IBS symptoms improved in 18 of 24 patients (75%) with antigliadin IgG and IgA and in 8 of 21 patients (38%) without the antibodies. Although constipation, diarrhea, and abdominal pain were reduced in patients with antigliadin IgG and IgA, only pain decreased in patients without these antibodies. Gastrointestinal transit normalized in a higher proportion of patients with antigliadin IgG and IgA. Anxiety, depression, somatization, and well-being increased in both groups. The presence of antigliadin IgG was associated with overall reductions in symptoms (adjusted odds ratio compared with patients without this antibody, 128.9; 95% CI, 1.16-1427.8; P = .04). Symptoms were reduced even in patients with antigliadin IgG and IgA who reduced gluten intake but were not strictly compliant with the GFD. In controls, a GFD had no effect on gastrointestinal symptoms or gut function.

CONCLUSIONS

Antigliadin IgG can be used as a biomarker to identify patients with IBS who might have reductions in symptoms, particularly diarrhea, on a GFD. Larger studies are needed to validate these findings. ClinicalTrials.gov: NCT03492333.

Molecular and Genetic Immune Biomarkers of Primary and Immune-Therapy Induced Hypophysitis: From Laboratories to the Clinical Practice

Hypophysitis is a rare and potentially life-threatening disease, characterized by an elevated risk of complications, such as the occurrence of acute central hypoadrenalism, persistent hypopituitarism, or the extension of the inflammatory process to the neighboring neurological structures. In recent years, a large number of cases has been described. The diagnosis of hypophysitis is complex because it is based on clinical and radiological criteria. Due to this, the integration of molecular and genetic biomarkers can help physicians in the diagnosis of hypophysitis and play a role in predicting disease outcome. In this paper, we review current knowledge about molecular and genetic biomarkers of hypophysitis with the aim of suggesting a possible integration of these biomarkers in clinical practice.

Celiac Disease in Asia beyond the Middle East and Indian subcontinent: Epidemiological burden and diagnostic barriers

Celiac Disease (CD) had been considered uncommon in Asia for a long time. However, several studies suggested that, in the Indian subcontinent and Middle East countries, CD is present and as prevalent as in Western countries. Outside these Asian regions, the information about the epidemiology of CD is still lacking or largely incomplete for different and variable reasons. Here, we discuss the epidemiological aspects and the diagnostic barriers in several Asian regions including China, Japan, Southeast Asia and Russia/Central Asia. In some of those regions, especially Russia and Central Asia, the prevalence of CD is very likely to be underestimated. Several factors may, to a different extent, contribute to CD underdiagnosis (and, thus, underestimation of its epidemiological burden), including the poor disease awareness among physicians and/or patients, limited access to diagnostic resources, inappropriate use or interpretation of the serological tests, absence of standardized diagnostic and endoscopic protocols, and insufficient expertise in histopathological interpretation.

Small bowel capsule endoscopy in refractory celiac disease: a luxury or a necessity?

Background

Small bowel capsule endoscopy (SBCE) has an established role in the management of refractory celiac disease (RCD) for the detection of complications. The aim of this study was to define the role of SBCE in the management of patients with RCD.

Method

Patients with histologically confirmed RCD who underwent successive SBCEs were recruited retrospectively from 2 tertiary centers.

Results

Sixty patients with RCD were included. The percentage extent of the affected small bowel (SB) mucosa improved on repeating a second SBCE in 26 patients (49.1%) (median 27.6% vs. 18.1%, P=0.007). Patients with RCD type II had more extensive disease than those with RCD type I on first (41.4% vs. 19.2%, P=0.004) and second (29.8% vs. 12.0%, P=0.016) SBCE. Patients with RCD type I tended to show a greater improvement in percentage of abnormal SB involved on repeat SBCE compared to those with RCD type II (P=0.049). Nine patients (15%) had RCD-related complications. Five patients developed ulcerative jejunoileitis, 3 patients developed enteropathy-associated T-cell lymphoma, and 1 patient developed cutaneous T-cell lymphoma.

Conclusions

SBCE can be a useful tool for monitoring the effects of treatment, primarily following its initiation. Patients with RCD type II have more extensive SB disease, equating to a more aggressive disease pattern.

Network Analysis of Common Genes and Transcriptional Factors between Celiac Disease and Inflammatory Bowel Diseases

BACKGROUND

Understanding the associations among different disorders remarkably improves their diagnosis and treatments. Celiac disease is the most complicated and prevalent form of immune-mediated diseases. On the other hand, inflammatory bowel diseases lead to inflammation of the intestine with an unknown cause. Although inflammatory bowel diseases have been often thought of as an autoimmune disorder, they can be triggered by whatever that can lead to the inflammation in the whole bowel. Henceforth, both aforementioned diseases are related to autoimmune attacks and cause a sort of inflammatory event, which exploring trade-off among them supposedly will lead to discovering important genes and, in turn, to the possible common therapeutic protocols. In the current study, we aimed to determine the correlation between the common genes in celiac disease and inflammatory bowel diseases.

METHODS

314 and 851 genes correlated with celiac disease and inflammatory bowel diseases respectively extracted from DisGeNET were subjected to an in-silico data analysis framework to mine prognosticates genes and the associated pathways.

RESULTS

149 shared genes between these diseases regulated by highlighted transcription factors NFKB1, IRF1, STAT1, HSF1, GATA3 were characterized as discriminating molecules, which by further screening were enriched in pathways mostly involved in apoptosis, T cell activation, and cytokine, chemokine, and interleukin signaling.

CONCLUSION

We observed that the identified common genes were associated with a wide range of pathogenic mechanisms underlying these diseases.

Celiac Disease Complicated by Rhabdomyolysis

At 37 years old, a patient developed chronic watery diarrhea, generalized pain, severe hypokalemia and elevated creatine kinase levels. She was thought to have rhabdomyolysis due to hypokalemia from chronic diarrhea. No organic cause was found. Her symptoms subsided with potassium correction, but hypokalemia persisted; she visited our hospital at 44 years old. Endoscopy detected prominent atrophy of the intestinal villi. Histology indicated Marsh-Oberhuber type-3b disease. Anti-gliadin and anti-tissue transglutaminase IgA antibody tests were positive. She was diagnosed with celiac disease and started on a gluten-free diet, which improved her symptoms. This report is only the tenth of its kind worldwide.

Beyond the HLA Genes in Gluten-Related Disorders

Most common food grains contain gluten proteins and can cause adverse medical conditions generally known as gluten-related disorders. Celiac disease is an immune-mediated enteropathy triggered by gluten in individuals carrying a specific genetic make-up. The presence of the human leukocyte antigens (HLA)-DQ2 and HLA-DQ8 haplotypes together with gluten intake is a necessary, although not sufficient, condition, to develop celiac disease. Fine mapping of the human genome has revealed numerous genetic variants important in the development of this disease. Most of the genetic variants are small nucleotide polymorphisms located within promoters and transcriptional enhancer sequences. Their importance is underlined by an increased risk in DQ2/DQ8 carriers who also have these non-HLA alleles. In addition, several immune-mediated diseases share susceptibility loci with celiac disease, shedding light on the reasons for co-occurrence between these diseases. Finally, most of the genes potentially involved in celiac disease by fine genetic mapping of non-HLA loci were confirmed in gene expression studies. In contrast to celiac disease, very little is known about the genetic make-up of non-celiac wheat sensitivity (NCWS), a clinically defined pathology that shares symptoms and gluten dependence with the celiac disease. We recently identified differentially expressed genes and miRNAs in the intestinal mucosa of these patients. Remarkably, the differentially expressed genes were long non-coding RNAs possibly involved in the regulation of cell functions. Thus, we can speculate that important aspects of these diseases depend on alteration of regulatory genetic circuits. Furthermore, our finding suggests that innate immune response is involved in the pathogenic mechanism of NCWS. This review is intended to convey the idea that in order to fully understand celiac disease and its relationship with other gluten-related disorders, it is worth learning more about non-HLA variants.

The HLA complex and coeliac disease

The Human Leukocyte Antigen (HLA) has a crucial role in the development and pathogenesis of coeliac disease (CD). The genes HLA-DQA1 and HLA-DQB1, both lying in this region and encoding the HLA-DQ heterodimer, are the main genetic predisposing factors to CD. Approximately 90% of CD patients carry the heterodimer HLA-DQ2.5, leaving only a small proportion of patients with lower risk heterodimers (HLA-DQ8, HLA-DQ2.2 or HLA-DQ7.5). These HLA-DQ molecules act as receptors present in the surface of antigen presenting cells and show high affinity for deamidated gluten peptides, which bind and present to CD4⁺ T cells. This triggers the immunological reaction that evolves into CD. Since specific HLA genetics is present in almost the totality of CD patients, HLA typing has a very high negative predictive value, and it can be used to support diagnosis in specific scenarios. HLA risk has been associated to different CD-related features, such as age at onset, clinical outcomes, antibody levels and grade of histological lesion; but further research is needed. HLA-DQ genotypes have been also suggested to modulate the composition of the gut microbiota.

Distribution of HLA-DQ risk genotypes for celiac disease in Ethiopian children

Most patients with celiac disease are positive for either HLA‐DQA1*05:01‐DQB1*02 (DQ2.5) or DQA1*03:01‐DQB1*03:02 (DQ8). Remaining few patients are usually DQA1*02:01‐DQB1*02 (DQ2.2) carriers. Screenings of populations with high frequencies of these HLA‐DQA1‐DQB1 haplotypes report a 1% to 3% celiac disease prevalence. The aim was to determine the prevalence of HLA‐DQ risk haplotypes for celiac disease in Ethiopian children. Dried blood spots collected from 1193 children from the Oromia regional state of Ethiopia were genotyped for HLA‐DQA1 and DQB1 genotyping using an asymmetric polymerase chain reaction (PCR) and a subsequent hybridization of allele‐specific probes. As references, 2000 previously HLA‐genotyped children randomly selected from the general population in Sweden were included. DQ2.2 was the most common haplotype and found in 15.3% of Ethiopian children, which was higher compared with 6.7% of Swedish references (P < .0001). Opposed to this finding, DQ2.5 and DQ8 occurred in 9.7% and 6.8% of Ethiopian children, which were less frequent compared with 12.8% and 13.1% of Swedish references, respectively (P < .0001). The DQ2.5‐trans genotype encoded by DQA1*05‐DQB1*03:01 in combination with DQ2.2 occurred in 3.6% of Ethiopian children, which was higher compared with 1.3% of Swedish references (P < .0001). However, when children with moderate high to very high‐risk HLA genotypes were grouped together, there was no difference between Ethiopian children and Swedish references (27.4% vs 29.0%) (P = .3504). The frequency of HLA risk haplotypes for celiac disease is very similar in Ethiopian and Swedish children. This finding of importance will be useful in future screening of children for celiac disease in Ethiopia.

Persistent organic pollutant exposure and celiac disease: A pilot study

Celiac disease affects approximately 1% of the population worldwide. Little is known about environmental factors that may modulate risk in genetically susceptible populations. Persistent organic pollutants (POPs) are known endocrine disruptors and, given the interplay between the endocrine and immune systems, are plausible contributors to celiac disease. The current study aims to elucidate the association between POPs and celiac disease. We conducted a single-site pilot study of 88 patients recruited from NYU Langone's Hassenfeld Children's Hospital outpatient clinic, 30 of which were subsequently diagnosed with celiac disease using standard serology and duodenal biopsy examination. Polybrominated diphenyl ether (PBDEs), perfluoroalkyl substances (PFASs), and p,p'-dichlorodiphenyldichloroethylene (DDE) and HLA-DQ genotype category were measured in blood serum and whole blood, respectively. Multivariable logistic regressions were used to obtain odds ratios for celiac disease associated with serum POP concentrations. Controlling for sex, race, age, BMI, and genetic susceptibility score, patients with higher serum DDE concentrations had 2-fold higher odds of celiac disease (95% CI: 1.08, 3.84). After stratifying by sex, we found higher odds of celiac disease in females with serum concentrations of DDE (OR = 13.0, 95% CI = 1.54, 110), PFOS (OR = 12.8, 95% CI = 1.17, 141), perfluorooctanoic acid (OR = 20.6, 95% CI = 1.13, 375) and in males with serum BDE153, a PBDE congener (OR = 2.28, 95% CI = 1.01, 5.18). This is the first study to report on celiac disease with POP exposure in children. These findings raise further questions of how environmental chemicals may affect autoimmunity in genetically susceptible individuals.

CD1 gene polymorphism and susceptibility to celiac disease: Association of CD1E*02/02 in Moroccans

CD1 glycoproteins are a class of antigen presenting molecules that bind and present non-peptidic antigens (lipids and glycolipids) for immune recognition. CD1 polymorphisms, although limited, could have a critical role in antimicrobial, anticancer, and autoimmune responses and disease susceptibility. Ethnic differences and interactions between genetic and environmental factors make it attractive the study of these molecules in autoimmune inflammatory disorders, such as celiac disease (CD), in which a strong genetic predisposition (HLA-DQ2/DQ8) and pressure of environmental factors have a central role. CD1A, CD1D and CD1E polymorphisms in exon 2 were assessed in patients from Morocco affected by CD, using direct sequencing analysis, in order to investigate possible associations with the disease in a North African population. Differences in genotype and haplotype distribution of CD1E between celiac patients and controls were found: in particular, an increase of CD1E*02/02 homozygous (OR 2.93, CI 1.30-6.59, p = 0.007) and CD1A*02-E*02 estimated haplotypes in CD, compared with controls. Frequencies of CD1A and CD1D genotypes/alleles were not different between groups. CD1E*02/02, previously suggested as a potential immune protective genotype to malaria susceptibility, could be an additional gene involved in celiac risk in this geographic area.

Carrier frequency of HLA-DQB1*02 allele in patients affected with celiac disease: A systematic review assessing the potential rationale of a targeted allelic genotyping as a first-line screening

BACKGROUND

Celiac Disease (CD) is an immune-mediated disorder, in which the HLA immunogenetic background (DQ2 and DQ8 heterodimers) and environmental trigger (gluten) are well established. Indeed, both factors are necessary – but not sufficient – to develop CD. However, it is very likely that CD is underdiagnosed in both developing and developed countries, due to several aspects, including the fact that a lot of patients present mild and/or atypical symptoms, without the presence of any recognized risk factors. Therefore, the possibility and feasibility of widened screening strategies to identify CD patients are debated.

AIM

To provide further evidence of the main epidemiological importance of HLA-DQB1*02 allele in the population of CD patients.

METHODS

We performed a systematic search in PubMed, EMBASE, Cochrane, Web of Science and Scopus databases, in order to produce a systematic review assessing the carrier frequency of HLA-DQB1*02 allele in the celiac population. Following the PRISMA guidelines, we retrieved all the original articles describing CD patients’ HLA-DQB1 genotype in such a way that could allow to assess the HLA-DQB1*02 carrier frequency among CD patients, along with the evidence of the appropriate diagnostic work-up to achieve a correct and final diagnosis of CD.

RESULTS

The final output of this systematic search in the medical literature consisted of 38 studies providing the appropriate HLA-DQB1 genotype information of the respective CD population. According to this systematic review, including a pool of 4945 HLA-DQ genotyped CD patients, the HLA-DQB1*02 carrier frequency was 94.94%, meaning that only 5.06% of CD patients were completely lacking this allelic variant. Interestingly, if we consider only the studies whereby the prevalence of CD patients affected with type 1 diabetes mellitus was supposed or clearly established to be very low, the frequency of non-HLA-DQB1*02 carriers among CD patients dropped to 3.65%.

CONCLUSION

Such a high carrier frequency of the HLA-DQB1*02 allelic variant (which is > 95%-96% in CD patients without risk factors, like type 1 diabetes mellitus comorbidity) might be exploited to consider a cost-effective and widened screening approach. If a sustainable strategy could be implemented through a low-cost targeted genetic test to detect the individual presence of HLA-DQB1*02 allele, an appropriate algorithm for serological screening in individuals resulting to be genetically predisposed to CD, might be considered.

Increased Prevalence of Celiac Disease in School-age Children in Italy

BACKGROUND & AIMS

Celiac disease is one of the most common diseases worldwide, with an apparent trend of increasing prevalence. We investigated the prevalence of celiac disease in children in Italy in 2015-2016 and compared that with data from 25 years ago.

METHODS

We screened 4570 children (5-11 years old, 80.1% of the eligible population) from metropolitan areas of Ancona and Verona for HLA genes associated with increased risk of celiac disease, and for total serum levels of IgA and IgA class anti-tissue transglutaminase in HLA positives. Diagnoses of celiac disease were confirmed by detection of anti-endomysial antibody and analysis of intestinal biopsies. The prevalence of celiac autoimmunity and celiac disease were calculated and compared with values from the same geographical area during the years 1993-1995, after adjustment for the different diagnostic algorithm.

RESULTS

We identified 1960 children with celiac disease-associated haplotypes (43% of children screened; 95% CI, 40.8%-45.2%). The prevalence of celiac disease autoimmunity in the HLA-positive subjects was 96/1706 (5.62%; 95% CI, 4.53%-6.71%) and 54 of these children satisfied the diagnostic criteria for celiac disease. In the eligible population there were other 23 known cases of celiac disease. The overall estimated prevalence of celiac disease was 1.58% (95% CI, 1.26%-1.90%); this value is significantly higher than the 1993-1995 adjusted prevalence (0.88%; 95% CI, 0.74%-1.02%).

CONCLUSIONS

We found the prevalence of celiac disease in children in Italy to be greater than 1.5%; this value has increased significantly over the past 25 years. Studies are needed to determine the causes of this large increase.

Genetic predisposition to celiac disease in Kazakhstan: Potential impact on the clinical practice in Central Asia

Background

Celiac disease (CD) is a systemic immune-mediated disorder developing in HLA genetically predisposed individuals carrying HLA-DQ2 and/or HLA-DQ8 molecules. Recent evidences supported a predominant importance of HLA-DQB1 locus and, in particular, HLA-DQB1*02 alleles. This diagnosis is poorly considered in Kazakhstan, because of the assumption that CD is not prevalent in this population.

Objective

To demonstrate that the genetic predisposition to CD in Kazakhstan is not negligible and is actually comparable to Western populations.

Methods

Through the analysis of HLA-DQ genotypes of healthy bone marrow donors from Kazakhstan’s national registry, we estimated the HLA-related genetic predisposition to CD in the country.

Results

We demonstrated that the frequency of CD-related HLA-DQB1 alleles and, as a consequence, of predisposed individuals to CD in Kazakhstan is significant and comparable to countries with the highest disease prevalence.

Conclusion

Considering the dietary style in Kazakhstan, including wheat as a staple food, these results provided a preliminary background of knowledge to expect a significant CD prevalence in Kazakhstan and Central Asia by implementing appropriate and cost-effective diagnostic strategies.

HLA-DQ genotypes relative risks for celiac disease in Arabs: A case-control study

OBJECTIVES

It remains unknown what degree of risk is conferred by celiac disease (CD)-predisposing human leukocyte antigen (HLA)-DQ genotypes in Saudi Arabia compared with in Western countries. In this study, we aimed to determine the CD risk gradient associated with the HLA-DQ genotypes and to compare HLA-DQ genotypes between symptomatic patients with CD and screening-identified asymptomatic CD patients.

METHODS

We enrolled three groups of subjects, including 46 CD children diagnosed consecutively over the past 10 years, 54 CD children diagnosed during a mass screening of schoolchildren, and 192 healthy controls. All the participants were typed for the HLA-DQA1 and HLA-DQB1 genes by polymerase chain reaction sequence-specific oligonucleotide probes.

RESULTS

Comparing the patients with CD to controls, we identified 5 groups in the CD risk gradient: (i) very high risk associated with the DQ2.5/DQ8 genotype (odds ratio [OR] 46.93); (ii) high risk (homozygous DQ2.5, DQ2.5/DQ2.2; OR 4.12-5.04); (iii) intermediate risk (heterozygous DQ2.5, DQ8/DQ2.2; OR 1.61 and 1.67); (iv) low risk (DQ8, DQ2.2); and (v) very low risk (DQ2.x, DQX.5, DQX.x). Heterozygous DQ8 was more common in screening-identified group compared to symptomatic patients (13.0% vs 2.2%); however, other genotypes were very similar between the two groups.

CONCLUSION

The highest risk of developing CD in our Saudi Arabia population is associated with the DQ2.5/DQ8 genotype.

A Clinician's Guide to Celiac Disease HLA Genetics

Celiac disease is a common inflammatory disease triggered by dietary gluten in genetically susceptible individuals. The strongest and best-characterized genetic susceptibilities in celiac disease are class II human leukocyte antigen (HLA) genes known as HLA-DQ2 and DQ8. HLA genetic testing is available through a number of commercial and academic laboratories and is used in the evaluation of celiac disease and to identify at-risk family members. Importantly, HLA genetic testing has a high negative predictive value for celiac disease, but a low positive predictive value. Therefore, for a practicing clinician, it is important to understand when to order HLA genetic testing, what test to order, and how to interpret the result. This review provides a practical primer on HLA genetics in celiac disease.

Thymic stromal lymphopoietin levels are increased in patients with celiac disease

Thymic stromal lymphopoietin (TSLP) is a cytokine produced by epithelial cells in the lungs, skin, and intestinal mucosa and is involved in several physiological and pathological processes. In this study, we evaluated serum TSLP levels in patients with celiac disease (CD). The prospective study was conducted at a gastroenterology outpatient clinic between March 2018 and August 2018. Eighty-nine participants aged between 18 and 75 years were classified into following groups: 22 patients with newly diagnosed CD; 20 patients with CD who were compliant with a gluten-free diet (GFD); 32 patients with CD who were not compliant with a GFD; and 15 healthy controls. Demographic characteristics, disease duration, and selected biochemical and hematologic parameters were recorded and compared between groups. Median serum TSLP levels were 1193.65 pg/mL (range: 480.1-1547.1) in newly diagnosed CD patients, 110.25 pg/mL (range: 60.3-216.7) in CD patients who were compliant with a GFD, 113.1 pg/mL (range: 76.3-303.4) in CD patients who were not compliant with a GFD, and 57 pg/mL (range: 49-67.8) in healthy controls. Overall, there was a significant difference in serum TSLP levels between groups (p = 0.001). Patients with newly diagnosed CD had the highest serum TSLP levels. There was no significant difference in serum TSLP levels between patients with CD who were and were not compliant with a GFD. TSLP appears to be involved in the pathogenesis of CD. Further studies are required to determine if the TSLP signaling pathway can be used in the treatment of CD.

Role of HLA-DQ typing and anti-tissue transglutaminase antibody titers in diagnosing celiac disease without duodenal biopsy in type 1 diabetes: A study of the population-based pediatric type 1 diabetes cohort of Western Australia

AIM

The primary aim of the present study was to determine if it is cost effective to use human leukocyte antigen (HLA) typing as a first-line screening test for celiac disease (CD) in children with type 1 diabetes (T1D), as recommended by the European Society of Paediatric Gastroenterology Hepatology and Nutrition (ESPGHAN). The second aim was to investigate whether anti-tissue transglutaminase IgA (anti-tTGA) antibodies can be used to diagnose CD without the need for a confirmatory duodenal biopsy in T1D.

METHODS

Data for all T1D patients aged <18 years, who attended the diabetes clinics in Western Australia up to June 2017, were extracted from the Western Australian Children's Diabetes Database (WACDD) and analyzed for their demographic data and CD permissive HLA alleles (DQ2, DQ8, and DQ7). For T1D patients already diagnosed with CD, the mode of diagnosis of CD, anti-tTGA titers, and CD permissive HLA alleles were analyzed.

RESULTS

Of the 936 eligible T1D patients identified, HLA-DQ typing was available for 551 (59%). Of these 551 patients, 504 (91.2%) were positive for celiac permissive HLA alleles. Eight percent (n = 75) of the T1D patients had a co-diagnosis of CD. High anti-tTGA titers were observed in those who were diagnosed with a positive duodenal biopsy.

CONCLUSION

HLA-DQ typing is not cost effective as a first-line screening test for CD in T1D patients because of over-representation of CD permissive HLA alleles in this group. Anti-tTGA titers may be useful in diagnosing CD in T1D without duodenal biopsy, as high levels were found to be strongly predictive of CD.

HLA-DQ Genotyping, Duodenal Histology, and Response to Exclusion Diet in Autistic Children With Gastrointestinal Symptoms

OBJECTIVES

A correlation between autism spectrum disorders (ASDs) and gastrointestinal (GI) problems, and a possible link between gluten consumption and ASD have been increasingly reported. Gluten/casein-free diet (GCFD) is often undertaken, with conflicting results. This study aimed at evaluating the distribution of human leukocyte antigen (HLA)-DQ2/DQ8 typing among patients with ASD with GI symptoms, together with its correlation with duodenal histology and response to GCFD.

METHODS

Between 2002 and 2015 all patients with ASD with GI symptoms referred to our outpatient clinic, displaying clinical, laboratory, or ultrasound findings suggestive of organic disease, underwent endoscopy, celiac disease (CD) serum antibodies testing and HLA-DQ2/DQ8 genotyping. Patients were prescribed a 6-month GCFD, and then clinically reassessed.

RESULTS

Among 151 enrolled patients, 134 (89%) were negative for CD-specific antibodies; 72 (48%) were positive for HLA-DQ2/DQ8; and 56 (37%) showed duodenal microscopic inflammation. Clinical improvement was observed in non-CD patients irrespective of the rigorous or partial adherence to the diet, being the difference nonstatistically significant. Response to diet was related to the presence of histological duodenal alterations at baseline (odds ratio 11.323, 95% confidence interval 1.386-92.549 for Marsh 2 pattern), but not to HLA-DQ2/DQ8 positivity (odds ratio 1.120, 95% confidence interval 0.462-2.716).

CONCLUSIONS

Our data suggest that children with ASD with GI symptoms have a high prevalence of duodenal intraepithelial lymphocytic infiltration, which seems to be linked to a mechanism other than autoimmune response to gluten consumption. Alteration of duodenal histology, but not the HLA-DQ2/DQ8 status, was associated with clinical response to the diet.

Relevance of HLA-DQB1*02 Allele in the Genetic Predisposition of Children with Celiac Disease: Additional Cues from a Meta-Analysis

Background and Objectives: Celiac disease (CD) is a multifactorial immune-mediated disorder, triggered by the ingestion of gluten in genetically-predisposed subjects carrying MHC-DQ2 and -DQ8 heterodimers, which are encoded by four HLA-DQ allelic variants, overall. This meta-analysis aims at providing further epidemiological support to the predominant relevance of one specific allele, namely HLA-DQB1*02, in the predisposition and genetic risk of CD. Materials and Methods: We performed a search of MEDLINE/PubMed, Embase, Web of Science, and Scopus, retrieving all publications (case-control study, cross-sectional, and retrospective cohort study) on the association between HLA class II polymorphisms and first-degree relatives (FDRs) of children with CD. After a critical reading of the articles, two investigators independently performed data extraction according to the following inclusion criteria: HLA class II genes, any DQ and DR molecules, and CD diagnosed following the current clinical guidelines. A third participant was consulted for discussion to reach an agreement concerning discrepancies. Results: Our search strategy selected 14 studies as being eligible for inclusion, and those were submitted for data extraction and analysis. These studies were published between 1999 and 2016 and, collectively, enrolled 3063 FDRs. Positive and negative likelihood ratios (LR+ and LR-, respectively) for CD diagnosis, according to the presence of the HLA-DQ genotype coding a complete MHC-DQ2 and/or MHC-DQ8 molecules, were 1.449 (CI 1.279-1.642) and 0.187 (CI 0.096-0.362), respectively. If only the isolated presence of HLA-DQB1*02 allele is considered, the pooled estimation of LR+ was 1.659 (CI 1.302-2.155) and, importantly, the LR- still showed a very good discriminatory power of 0.195 (CI 0.068-0.558). Conclusions: Through our differential meta-analysis, comparing the presence of the genotype coding the full MHC-DQ2 and/or DQ8 molecules with the isolated presence of HLA-DQB1*02 allelic variant, we found that the LR- of the latter analysis maintained the same value. This observation, along with previous evidences, might be useful to consider potential cost-effective widened screening strategies for CD in children.

Physician Review of a Celiac Disease Risk Estimation and Decision-Making Expert System

Objective: Celiac disease is a genetic disease affecting people of all ages, resulting in small intestine enteropathy. It is considered to be a clinical chameleon. Average prevalence of celiac disease is 1 out of 100 people with data indicating the risk may be as high as 22% for those with first-degree relatives with the disease. Eighty-three percent of people with celiac disease may be undiagnosed. Average duration to diagnosis is 10 years. Data indicate that there is a lack of consensus regarding diagnostics and symptomatology.Method: A clinical decision support system (CDSS) was developed using Exsys Corvid for expert analysis (CD-CDSS). The CD-CDSS was divided into symptoms and manifestations with 80 points of navigation, and a serology section, and was validated by 13 experts in the field of celiac disease using a 10-statement 5-point Likert scale.Results: This scale was analyzed using Cronbach's alpha reliability coefficient, which was calculated using SPSS and revealed good internal consistency and reliability with a result of 0.813. One hundred percent of experts agreed that the CD-CDSS is capable of guiding a health care professional through the diagnostic process, contains an accurate list of symptoms based on the clinical literature, and can foster improved awareness and education about celiac disease and that there is a need for this system.Conclusions: A celiac disease risk estimation and decision-making expert system was successfully developed and evaluated by medical professionals, with 100% agreeing that this CD-CDSS is medically accurate and can guide health care professionals through the diagnostic process.

Overview in the clinical management of patients with seronegative villous atrophy

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

Screening for coeliac disease in 1624 mainly asymptomatic children with type 1 diabetes: is genotyping for coeliac-specific human leucocyte antigen the right approach?

OBJECTIVES

To investigate the frequency of coeliac disease (CD)-specific human leucocyte antigen (HLA) genotypes in paediatric patients with type 1 diabetes (T1D), who are known to have a higher prevalence of CD than the general population, and to evaluate whether HLA genotyping is a suitable first-line screening method for CD.

STUDY DESIGN

The study was a multicentre observational analysis of patients with T1D aged <20 years of whom a subgroup had undergone HLA genotyping. Patient data were retrieved from the Diabetes Prospective Follow-up database, a large diabetes follow-up registry. The present analysis included data from 439 centres throughout Germany, Austria, Switzerland and Luxembourg.

RESULTS

In March 2017, the database contained 75 202 patients with T1D (53% male, mean age (SD) 14.6 (4.1) years, mean age at diagnosis 8.8 (4.3) years and mean diabetes duration 5.8 (4.3) years). 1624 patients had undergone coeliac-specific HLA genotyping, of whom 1344 (82.8%) were positive for HLA-DQ2, HLA-DQ8 or both, while 17.2% had no coeliac-specific HLA-markers. 26.6% of at-risk patients had a clinical suspected diagnosis of CD, and 3.6% had biopsy-proven CD.

CONCLUSIONS

Genotyping for HLA-DQ2, HLA-DQ8 or both is positive in the vast majority (>80%) of patients with T1D. Therefore, screening for coeliac-specific HLA genotypes as a first-line test is not a suitable method to exclude CD in T1D. Regular screening for coeliac-specific antibodies in T1D is still recommended.

Prevalence of Celiac Disease in a Long-term Study of a Spanish At-genetic-risk Cohort From the General Population

OBJECTIVES

To perform long-term celiac disease (CD) screening in an HLA-DQ2 (+) cohort from the general population and to assess the influence of risk genotypes on its development.

METHODS

In 2004, an HLA-DQ2 (+) cohort was selected. After the first CD screening at age 2 to 3 years, we performed a follow-up screening 8 to 10 years later. Antitransglutaminase 2 antibodies were determined using a rapid test kit. Results were confirmed by serum IgA antitransglutaminase 2 and IgA endomysial antibody determination. CD diagnosis was carried out by intestinal biopsies. Four HLA-DQ2 genotypic groups were used: G1: DQ2.5/DQ2.5 (G1A) or DQ2.5/ DQ2.2 (G1B); G2: DQ2.2/DQ7.5 (DQ2.5 trans); G3: DQ2.5/ X; G4: DQ2.2/X.

RESULTS

CD prevalence after 10 years of follow-up was 5.8% (95% confidence interval 3.8-8.7). One of every 3 HLA-DQ2(+) children carried at least 1 haplotype DQ2.2 or DQ7. The homozygous genotype DQ2.5/DQ2.5 and the HLA-DQ2.5 trans genotype increased CD risk 4- and 3-fold, respectively. The homozygous genotype DQ2.5/ DQ2.2 did not increase the CD risk. Children carrying G1 or G2 genotypes were diagnosed with CD earlier and more frequently during the follow-up compare with those carrying G3 or G4 genotypes. Approximately 81% of children with spontaneous antibody negativization after the first screening maintained negative antibodies.

CONCLUSIONS

A repeated screening of at-risk children during their follow-up allowed us to diagnose new CD cases. In our cohort, HLA- DQ2.5 trans genotype conferred a higher risk in the development of CD than HLA- DQ2.5/DQ2.2. The majority of children with potential CD and CD autoimmunity at 10 years of age remained healthy.

HLA-DQ2 homozygosis increases tTGA levels at diagnosis but does not influence the clinical phenotype of coeliac disease: A multicentre study

BACKGROUND AND PURPOSE

Magnitude of gluten-specific T-cell responses in coeliac disease (CD) might be dependent on HLA-DQ2 gene dose. We aimed to investigate the effects of HLA-DQB1*02 allele dose on clinical outcomes.

METHODS

We reviewed the charts of all coeliac patients attending to three Hungarian university clinics after 1997 and included those patients, who (a) were diagnosed with CD, (b) underwent high-resolution HLA typing and (c) were ≥18 years at the time of data collection. HLA typing was performed to determine DQB1*02 allele dose. Patients were divided into risk groups by DQB1*02 allele dose, as follows: high-, intermediate- and low-risk groups corresponded to a double, single and zero doses, respectively. We used ANOVA and Pearson's chi-squared test to explore association between HLA risk and clinical variables.

RESULTS

A total of 727 coeliac patients attended the clinics but only 105 (14.4%) patients were eligible for inclusion. High, intermediate and low HLA risk patients comprised 35.3%, 52.3% and 12.3% of the study population, respectively. Double dose of HLA-DQB1*02 was more frequent in patient with high tTGA level (>10 times the upper limit of normal; p = 0.045). Gene dose was not associated with younger age at diagnosis (p = 0.549), gender (p = 0.739), more severe diagnostic histology (p = 0.318), more frequent classical presentation (p = 0.846), anaemia (p = 0.611), metabolic bone disease (p = 0.374), dermatitis herpetiformis (p = 0.381) and autoimmune diseases (p = 0.837).

CONCLUSIONS

Our study shows a significant gene dose effect in terms of tTGA level at diagnosis, but no significant association between HLA-DQB1*02 allele dose and the clinical outcomes in CD.

Who Should Be Gluten-Free? A Review for the General Practitioner

Historically, a gluten-free diet was recommended only for those with celiac disease or IgE-mediated wheat allergy. With changes in food allergy labeling in the United States and the publication of several best-selling books, gluten-related disorders have come to the forefront of popular culture. As a result, there has been a dramatic increase in the number of gluten-free diet followers, many for nontraditional reasons. As "going gluten-free" has become mainstream, it is imperative that health care providers acquire the knowledge to identify true gluten-related disorders to effectively counsel their patients and minimize potential complications from following such a restrictive diet.

Genetic susceptibilty and celiac disease: what role do HLA haplotypes play?

Celiac disease is a chronic immune-mediated enteropathy triggered by exposure to dietary gluten in genetically predisposed individuals. Many genes involved in the pathogenesis have been identified and a crucial role is known to be played by the Human Leukocyte Antigen (HLA) system. The main determinants for genetic susceptibility are HLA-DQA1 and HLA-DQB1 genes encoding for HLA-DQ2 and HLA-DQ8 molecules, carried by almost all patients affected. However, since HLA-DQ2 and HLA-DQ8 heterodimers explain almost 40% of the disease heritability, HLA typing should not be applied in diagnosis, but exclusively to clarify uncertain diagnoses, considering its negative predictive value. (www.actabiomedica.it)

Validation of a novel single-drop rapid human leukocyte antigen-DQ2/-DQ8 typing method to identify subjects susceptible to celiac disease

Background and Aim

Human leukocyte antigen (HLA)‐DQ2 and/or ‐DQ8 is an essential risk factor for celiac disease (CD). About 90–95% of patients with CD carry HLA‐DQ2/‐DQ8 alleles, and HLA‐DQ typing is considered an additional diagnostic test. Conventional polymerase chain reaction (PCR)‐based HLA‐DQ typing methods are expensive, complex, and a time‐consuming process. We assessed the efficacy of a novel HLA‐DQ typing method, “Celiac Gene Screen,” for the detection of CD‐associated HLA haplotypes.

Methods

To assess the diagnostic performance of the Celiac Gene Screen test, 100 ethylenediaminetetraacetic acid (EDTA) blood samples, already characterized by the conventional HLA‐DQ typing method, that is, PCR sequence‐specific oligonucleotide probes (PCR‐SSOP), a concordance between both the methods were explored. For validity, a further 300 EDTA blood samples with unknown HLA‐DQ status were genotyped using the Celiac Gene Screen test, including 141 samples from CD, 56 first‐degree relatives (FDRs) of CD and 103 samples from controls.

Results

Of the 100 samples with known status of HLA‐DQ alleles, 79 samples were HLA‐DQ2 and/or ‐DQ8 positive, and 21 samples were HLA‐DQ2 and/or ‐DQ8 negative by conventional PCR. These 100 samples were re‐typed using the Celiac Gene screen kit; all 79 positives were typed positive, and 21 negatives were typed negative for HLA‐DQ alleles. Among 300 samples with unknown HLA‐DQ status, 118 of 141 (84%) patients with CD, 48 of 56 (86%) FDRs of CD, and 52 of 103 (50%) controls typed positive for HLA‐DQ alleles.

Conclusions

The Celiac Gene Screen HLA‐DQ typing method showed excellent concordance with the conventional HLA‐DQ typing method and could be a cost‐reducing and effective method for CD‐associated HLA screening.

Towards an individual screening strategy for first-degree relatives of celiac patients

Celiac disease (CD) is known to be more prevalent in first-degree relatives of patients. In this retrospective cohort study of 609 relatives between 1994 and 2016, we investigated the effect of sex, HLA type, and age at time of index celiac diagnosis. Pearson's chi-square test and Kaplan-Meier survival analysis were used as statistical analyses. CD screening was carried out for 427 relatives (70%), resulting in a prevalence of 15%. HLA typing in 335 relatives showed HLA-DQ2/DQ8 positivity in 87.5%. In 63% of children and all parents, celiac disease was diagnosed at first screening. It was diagnosed significantly more often in females, HLA-DQ2 homozygosity, and children (all p < 0.05). In children aged 0-1 year at time of index diagnosis, celiac disease was diagnosed after consecutive screening in 58%, after 3.9 ± 2.5 (max 10) years (p < 0.001).Conclusion: Future screening policies for relatives of celiac patients should include retesting, especially in HLA-positive relatives younger than 10 years of age. In addition, one-time celiac-specific antibody testing alone could be sufficient to rule out the disease in adolescent siblings and parents of newly diagnosed celiac patients. What is Known: • Celiac disease is more prevalent in first-degree relatives of celiac patients (risk 3-12%). • HLA-DQ2 homozygous sisters/daughters are at highest risk (25%). What is New: • If younger than 10 years of age, repeated testing is necessary in HLA-DQ2/DQ8-positive first-degree relatives when celiac disease is diagnosed in a family. • One-time celiac-specific antibody testing alone could be sufficient to rule out the disease in adolescent siblings and parents of newly diagnosed celiac patients.