Genetics of celiac disease

It Is High Time for Personalized Dietary Counseling in Celiac Disease: A Systematic Review and Meta-Analysis on Body Composition

The body composition of patients with celiac disease (CD), on which the effects of a gluten-free diet (GFD) are controversial, differs from that of the average population. In this study, we aimed to compare the body composition across CD patients before a GFD, CD patients after a one-year GFD and non-celiac control subjects. A systematic search was conducted using five electronic databases up to 15 July 2021 for studies that reported at least one of the pre-specified outcomes. In meta-analyses, weighted mean differences (WMDs) with 95% confidence intervals (CIs) were calculated. A total of 25 studies were eligible for systematic review, seven of which were included in meta-analysis. During a ≥1-year GFD, fat mass of CD patients, compared to that at baseline, significantly increased (WMD = 4.1 kg, 95% CI = 1.5 to 6.6, three studies). In CD patients after a ≥1-year GFD, compared to non-celiac controls, fat mass (WMD = -5.8 kg, 95% CI = -8.7 to -2.9, three studies) and fat-free mass (WMD = -1.9 kg, 95% CI = -3.0 to -0.7, three studies) were significantly lower. In conclusion, body composition-related parameters of CD patients differ from that of the non-celiac control subjects even after a longstanding GFD.

Anthropometric Parameters in Celiac Disease: A Review on the Different Evaluation Methods and Disease Effects

This review compiled anthropometric data from 29 original articles, published between 1995 and 2015, corresponding to a total sample of 6368 celiac disease subjects. Body mass index was the main parameter for measuring anthropometry (82.1%), followed by body mass (78.6%), body fat (51.7%), bone mineral density and bone mineral content (46.4%), and fat-free mass (44.8%). The main evaluation method was dual x-ray absorptiometry (83.3%), followed by bioimpedance (16.6%), skinfold thickness (16.6%), and isotope dilution (5.5%). This compilation suggests that celiac disease patients without a gluten-free diet (WGFD) and celiac disease patients with a gluten-free diet (GFD) show a lower body mass than the control group, with inconclusive data about WGFD versus GFD. Body mass index is lower in WGFD and GFD compared to control group, and is lower in WGFD compared to GFD. We observed lower values of FM and FFM in WGFD and GFD versus the control group. No difference was found between WGFD versus GFD. BMD and BMC are lower in WGFD versus GFD and GFD versus the control group, with inconclusive data about WGFD versus GFD. The findings of this review suggest that celiac disease patients must be periodically evaluated through anthropometric parameters, since the pathology has the potential to modulate such values even in a gluten-free diet, with these variables reflecting their healthy status. In parallel, the screening of different anthropometric assessment methodologies can provide support for more accurate evaluations by scientists and clinical professionals who work with celiac disease patients.

The relationship between 174 G/C and -572 G/C of IL-6 gene polymorphisms and susceptibility of celiac disease in the Iranian population

INTRODUCTION

Celiac disease (CD) is a chronic inflammatory intestinal disorder. Different immunological factors, including inflammatory cytokines, may play an important role in disease susceptibility.

AIM

To investigate the relationship between -174G/C and -572G/C gene polymorphisms and the serum level of interleukin 6 (IL-6) and susceptibility to CD in the Iranian population.

MATERIAL AND METHODS

In this case-control study blood samples were collected of 105 patients with CD and 106 healthy subjects randomly in 2016 and evaluated by polymerase chain reaction-restriction fragments length polymorphism (PCR-RFLP) method. A sequence was also used to confirm the results of both polymorphisms. The IL-6 concentration was measured using ELISA.

RESULTS

The results showed a significant relationship between polymorphism -572G in CD patients when compared with control subjects by genotype (p = 0.001) and alleles (p = 0.022), respectively. There was no significant relationship between polymorphism 174G and frequency of genotype, but an association of this polymorphism with the frequency of alleles (p = 0.034), age (p = 0.001), and body mass index (p = 0.003) was seen. The serum level of interleukin-6 was significantly associated only with rs1800796 (p < 0.001).

CONCLUSIONS

The results confirm previous studies in different parts of the world and indicate that IL-6 (572G/C) polymorphism may play a role in susceptibility to CD in the Iranian population.

Association between celiac disease and schizophrenia: a meta-analysis

BACKGROUND/OBJECTIVE

Recent epidemiologic studies have suggested that patients with celiac disease might be at an increased risk of schizophrenia. However, the data on this risk remain inconclusive. This meta-analysis was conducted with the aim to summarize all available evidence.

METHODS

A literature search was carried out using MEDLINE and Embase database from inception to June 2017. Studies that compared the risk of schizophrenia among patients with celiac disease versus individuals without celiac disease were included. Pooled odds ratio and 95% confidence interval were calculated using a random-effect, generic inverse-variance method.

RESULTS

Of the 284 retrieved studies, four met our eligibility criteria and were included in the analysis. We found a higher risk of schizophrenia among patients with celiac disease compared with individuals without celiac disease with the pooled odds ratio of 2.03 (95% confidence interval: 1.45-2.86). The statistical heterogeneity of this study was insignificant (I=0%).

CONCLUSION

This systematic review and meta-analysis found a significantly higher risk of schizophrenia among patients with celiac disease.

Understanding Celiac Disease From Genetics to the Future Diagnostic Strategies

Celiac disease (CD) is an autoimmune disorder characterized by the permanent inflammation of the small bowel, triggered by the ingestion of gluten. It is associated with a number of symptoms, the most common being gastrointestinal. The prevalence of this illness worldwide is 1%. One of the main problems of CD is its difficulty to be diagnosed due to the various presentations of the disease. Besides, in many cases, CD is asymptomatic. Celiac disease is a multifactorial disease, HLA-DQ2 and HLA-DQ8 haplotypes are predisposition factors. Nowadays, molecular markers are being studied as diagnostic tools. In this review, we explore CD from its basic concept, manifestations, types, current and future methods of diagnosis, and associated disorders. Before addressing the therapeutic approaches, we also provide a brief overview of CD genetics and treatment.

HLA-DQB1 Haplotypes and their Relation to Oral Signs Linked to Celiac Disease Diagnosis

Objectives:

Celiac disease (CD) is an autoimmune disorder that can be divided into typical and atypical forms. Atypical forms can show extraintestinal manifestations among which oral signs are very frequent. Considering that the pathogenesis of CD is related to a positivity to specific HLA-DQB1 haplotypes, we tested whether the presence of the HLA-DQB1*02 allele could be a hypothetical cause of the development of oral manifestations.

Subjects and Methods:

For this study was been examined the oral condition of 98 Sardinian patients, all affected by CD and all on a gluten-free diet for at least 1 year. Then was been determined each patient’s HLA-DQB1 haplotype and compared these results with clinical information.

Results:

The statistical analysis evidenced that the absence of the HLA-DQB1*02 allele predisposes to oral manifestations such as dental enamel defects (DED) and recurrent aphthous stomatitis (RAS) (Pvalue=5.98x10^-05, OR = 0.23, CI: (0.10 - 0.45) per each copy of the HLA allele).

Conclusions:

These results showed that the presence of the HLA-DQB1*02 allele influences the development of oral signs in a dose-dependent manner and also how the HLA haplotype connected to oral signs could have a fundamental role for the diagnosis of atypical forms of CD.

Evaluation of cleaning procedures for allergen control in a food industry environment

The hygiene of chicken processing surfaces and retention of the wheat protein gliadin and of protein in general on those surfaces were compared in 15 trials after 3 increasingly rigorous cleaning steps. Eleven different chicken products with wheat derivatives as a batter were prepared on 3 processing lines in 15 production runs selected at random over 6 mo (5 runs were thus replicates). Using surface swabs, surface hygiene was monitored by adenosine triphosphate (ATP) bioluminescence, gliadin by immunoassay, and protein by the Coomassie dye method. Gliadin was monitored in 14 trials, protein in 5, and all trials were monitored by ATP bioluminescence. In a typical trial, gliadin values normalized to uncleaned values fell from 100000 arbitrary units, to 6000 after rinsing, to 30 (foam, rinse), to not detected (sanitize, rinse). Parallel ATP bioluminescence values also decreased, but crucially, the relative gliadin value was less than the relative ATP value after foam and rinse in all 14 trials, a result unchanged after sanitize and rinse. In trials comparing ATP and protein, the relative ATP values exceeded the relative protein values in 4 of 5 trials after foaming and after sanitizing. Thus, for these 11 products, ATP bioluminescence was a surrogate indicator of residual gliadin and probably of residual protein. Absolute gliadin concentration on an uncleaned processing line was also the basis of modeling the risk of cross-contamination of gliadin in follow-up product, where the line was hypothetically left uncleaned between production runs. The results show that all follow-up product could be declared "gluten-free" under proposed legislation, and suggest that some industrial cross-contamination risks are currently overestimated.

Failure to respond to hepatitis B vaccine in children with celiac disease

OBJECTIVES

To determine whether children with celiac disease (CD) fail to show a response to hepatitis B virus (HBV) vaccine more frequently than children without CD.

PATIENTS AND METHODS

This was a prospective study that compared the response to HBV, tetanus, rubella, and Haemophilus influenzae type b (Hib) vaccines between children with CD and age- and sex-matched control subjects.

RESULTS

The study population included 26 patients with CD and 18 age- and sex-matched controls. All had received the full complement of childhood vaccinations. A significantly higher proportion of subjects in the CD group (14 of 26) failed to respond to HBV vaccine compared with controls (2 of 18; 53.9% vs 11.1%; P < 0.05). Patients with CD were 8.33 times more likely to test negative for hepatitis B surface antigen than control subjects (95% CI, 1.5-46.5). By contrast, all of the subjects in both groups tested positive for rubella antibodies; only 1 subject in the CD group tested negative for tetanus antibody versus none in the control group (3.9% vs 0%; P = 1.0). The percentage of subjects who tested negative for Hib antibodies was similar in the 2 groups (CD, 33.3%; control, 44.4%; P = 0.53).

CONCLUSIONS

More than 50% of children with CD do not show a response to standard vaccination regimens for HBV. Given the large number of children with CD throughout the world, this observation suggests that there is a large HBV-susceptible population despite widespread vaccination. Current immunization strategies may need to be reassessed to protect this population and achieve the goal of universal protection.

Polymorphism in L-Selectin, E-Selectin and ICAM-1 Genes in Asian Indian Pediatric Patients With Celiac Disease

Celiac disease (CD) follows an autoimmune course in which both genetic and environmental factors contribute to its development. A strong association with HLA class II molecules, predominantly HLA-DQ2, has been reported in most ethnic groups with CD. The aim of this study was to determine if genetic polymorphisms in L-selectin, E-selectin, and intercellular adhesion molecule-1 (ICAM-1) have any correlation with CD. We investigated 5 mutations, namely F206L in L-selectin, S128R and L554F in E-selectin, and G241R and K469E in ICAM-1, in 37 North Indian pediatric patients with CD. A significant increase in allele frequencies of 128R of E-selectin and the associated genotype SR was observed in patients. No significant differences were observed in the F206L polymorphism of L-selectin, or the G241R and E469K polymorphisms in the ICAM-1 gene in CD. This study illustrates that selectin gene polymorphism might contribute to the genetic background of CD and invites further investigation relevant to understanding the mechanisms underlying the immunopathogenesis of this autoimmune disease.

Serum nitric oxide levels in children with celiac disease

OBJECTIVES

To determine serum nitric oxide levels in pediatric patients with celiac disease and to compare them with the results obtained after 1 year of gluten-free diet.

METHODS

We studied serum nitric oxide levels in 41 newly diagnosed patients with celiac disease. Serum levels of nitric oxide were reevaluated after 1 year of gluten-free diet in 23 of them. Mean age was 10.4 +/- 3.4 years (range 2-17 years).

RESULTS

The levels of nitric oxide in pretreatment 41 patients with celiac disease and healthy children were detected as 198.33 +/- 20.22 micromol/L and 135.63 +/- 21.17 micromol/L, respectively (P = 0.0001). Serum nitric oxide level, measured in the blood samples 1 year after gluten-free diet, was 148.27 +/- 27.25 micromol/L (P = 0.001). Serum nitric oxide levels were statistically correlated with the degree of histologic changes in celiac disease. In the patients with celiac disease, pretreatment level of nitric oxide was not correlated with the levels of triglyceride, cholesterol, albumin, aspartate aminotransferase, alanine aminotransferase, or creatine kinase. We found correlations with the level of nitric oxide and Hb, mean corpuscular volume, and ferritin.

CONCLUSION

Higher serum nitric oxide levels found in children who had not compliance with gluten-free diet suggested the role of serum nitric oxide as an indicator of diet compliance. Because determination of serum nitric oxide is a simple, rapid, cheap, noninvasive, and highly sensitive method for celiac disease, we think that this parameter can be used in the evaluation of diet compliance in children with celiac disease or even instead of gluten challenge, due to more noninvasive property.

Prevalence of celiac disease in Turkish children

BACKGROUND

Celiac disease has emerged as a public health problem, and the disease prevalence varies among different races and nations. The present study was designed to investigate the prevalence of celiac disease in apparently healthy Turkish schoolchildren and to detect children with silent celiac disease.

METHODS

Healthy school children, 6 to 17 years of age, which there are 72,000 living in Erzurum were chosen as the study population. A total of 1,489 children were randomly selected by systematic sampling method. Samples were tested for anti- tissue transglutaminase IgA. Parents of the children who had positive test result were informed about the disease, and a small intestinal biopsy was proposed. A pathologist blinded to the serology results examined all biopsy specimens according to the modified Marsh criteria.

RESULTS

A total of 1,263 healthy school children were screened for celiac disease. Of subjects, 687 (54.4%) were boys and 576 (45.6%) were girls. Mean age was 11.9+/-3.4 years (range, 6-17 years). None of the patients had IgA deficiency. Of 1,263 children, 11 had positive anti-tissue transglutaminase IgA. Thus, the total seropositivity was 0.87%. Of seropositive children, 6 (54.6%) were boys and 5 (45.4%) were girls. We calculated the prevalence of celiac disease as 1:115. The prevalence of biopsy proven celiac disease was 1:158.

CONCLUSIONS

In this first celiac disease prevalence study in Turkey, we found that celiac disease is highly prevalent in healthy schoolchildren. Children with iron deficiency anemia and malnutrition should be evaluated more carefully with the understanding of the high celiac disease prevalence in Turkey.

High prevalence of celiac disease in autoimmune hepatitis detected by anti-tissue tranglutaminase autoantibodies

Celiac disease (CD) may be found in association with other autoimmune diseases. We investigated the relation between autoimmune hepatitis (AIH) and CD by assessing the prevalence of IgA and IgG anti-tissue transglutaminase (tTG) antibodies in AIH, and by verifying whether the findings were associated with clinical and histological features of CD. Forty-seven consecutive patients with AIH (type I: n = 39; type II: n = 8) were studied. One hundred patients with chronic hepatitis C, and 120 healthy blood donors were also studied as controls. We analyzed sera for the presence of IgA and IgG anti-tTG antibodies using a specific human recombinant tTG immunoenzymatic assay. Anti-tTG positive patients and controls were further tested for anti-endomysium antibodies (EMA) and HLA typing, and those found positive by either of these tests underwent duodenal biopsy to confirm a possible diagnosis of CD. Three of the 47 AIH patients (6.4%) were positive for IgA anti-tTG and EMA antibodies, and were subsequently confirmed to be affected with CD by small-bowel biopsy findings. No IgG anti-tTG positivity was found in the AIH patients. None of the controls were positive for IgA anti-tTG, and only one with chronic hepatitis C had a low positive reaction for IgG anti-tTG, which resulted as a false positive. The crude prevalence rate of CD in AIH was 63.8 per 1,000 (95% CI, 13.2-186.1), and it was significantly higher than that found in the general population in Italy (4.9 per 1,000; 95% CI, 2.8-7.8). The results of this study showed a high prevalence of CD in patients with AIH. For this reason, early serological screening testing for CD is strongly recommended for all AIH patients.

[Genetics and immunopathogenics aspects of the celiac disease: a recent vision]

BACKGROUND

Celiac disease, or gluten-sensitive enteropathy, is a strongly inherited condition. Although the genetic association of CD with the DQ2 and DQ8 HLA haplotypes has been known for long, others HLA and non-HLA genes are also important in the development of the disease. Celiac disease results of the combined effect of different normally functioning genes' products. The tissue damage in celiac disease is immunologically mediated and several effector mechanisms are responsible for the disease expression. The interplay between genetic, immunological and environmental factors explains the large spectrum of clinical, histological and serological alterations observed in the different stages of the disease development, pointing out to the polygenic nature of celiac disease.

CONCLUSION

The recent advances in the understanding of the immunopathogenesis, genetics and diagnoses of celiac disease have allowed the revision of strict concepts and previous criteria and their adequation to the new evidences, aiming a better diagnostic and orientation to celiac patients and relatives.

Hepatitis B vaccine nonresponse and celiac disease

OBJECTIVES

There is a genetic predisposition to hepatitis B vaccine nonresponse. The link between human leukocyte antigen (HLA) genotype and ineffective development of immunity to the hepatitis B vaccine has been characterized in multiple studies. Celiac disease has a strong association with a particular HLA genotype of DQ2; interestingly, this HLA genotype is seen in association with nonresponders to the hepatitis B vaccine. We report a disproportionate number of patients with celiac disease who are nonresponders to the hepatitis B vaccine series.

METHODS

We reviewed the hepatitis B vaccine records, serological tests for anti-hepatitis B surface antigen antibody (anti-HBs), and HLA genotypes of celiac disease patients identified as nonresponders to hepatitis B vaccine. Subjects were identified from a database of patients diagnosed with celiac disease at our institution or referred to our center for evaluation and management of celiac disease between November, 2000, and October, 2002.

RESULTS

A total of 23 subjects were reviewed. All had a clinical and pathological diagnosis of celiac disease. All subjects reported receiving the full series of hepatitis B vaccinations. Of the subjects, 19 had testing for hepatitis B vaccine response. Of these 19 subjects, 13 did not achieve long-term immunity as seen by the negative qualitative or quantitative anti-HBs antibody titer. All tested subjects were either homozygous or heterozygous for DQ2.

CONCLUSIONS

We postulate that celiac disease patients may have a significant predisposition to hepatitis B vaccine nonresponse. Both celiac disease and hepatitis B vaccine nonresponse is genetically mediated. Celiac disease patients may have a failure of induction of humoral immune response needed for development of long term immunity; the mechanism for this is unclear.

Pediatric celiac disease in India is associated with multiple DR3-DQ2 haplotypes

The role of human leukocyte antigen (HLA) DQ2 heterodimer (DQA1*0501-DQB1*0201) in presenting gluten peptides to effector T cells in celiac disease (CD) has been well documented. Because HLA-DQ2 is carried on DR3 haplotypes due to linkage disequilibrium, such haplotypes are encountered more frequently in patients with autoimmune disease. This study analyzed 35 North Indian children below 15 years of age and diagnosed to have CD as per the ESPGAN criteria, which included histopathologic alterations in duodenal biopsies, clinical response to gluten withdrawal, and presence of antiendomysial antibodies. The HLA class I and class II alleles were determined by polymerase chain reaction-sequence-specific primers, sequence-specific oligonucleotide probe, and reverse line strip molecular techniques. A statistically significant positive association of the disease with HLA-DRB1*03 (94.2% versus 22.1% in controls, chi(2) = 73.4, p = 7.54E-11), and a negative association with DRB1*15 (chi(2) = 7.4, p = 6.5E-03) and DRB1*13 alleles was observed. The HLA-DQB1*0201 was observed in all the 35 patients (100%), whereas the DQ2 heterodimer alpha(0)beta(0) occurred in 97.1% of CD patients (31.4% in double dose, 65.7% in single dose) and revealed significant deviation from healthy controls (chi(2) = 102.08, p = 7.56E-11). Further analysis revealed involvement of multiple DR3+ve haplotypes with CD in Indians, of which A26-B8-DR3 was the most common DR3 haplotype among patients (34.28%, chi(2) = 40.57, p = 2.65E-10) followed by Ax-B21-DR3 (11.4%) (chi(2) = 13.8, p = 2E-04) and the classical Caucasian haplotype A1-B8-DR3 (5.7%). The former two haplotypes are characteristic of Asian Indians and are involved in the development of CD. We conclude that the high risk DR3 haplotypes that play a crucial role in the development of CD are unique in Asian Indians. Detailed analysis of these haplotypes in Indian patients with autoimmune diseases may help understand the influence of other intervening genes within the major histocompatibility complex.

Genetic factors underlying gluten-sensitive enteropathy

Genetic epidemiology clearly has shown that there is a genetic predisposition to gluten-sensitive enteropathy (GSE), or celiac disease. The strong genetic component, as determined by the lambda sib (lambda s), has been calculated to lie in the range of 7.5 to 30, based on a 5% to 10% recurrence risk for siblings. Ninety-five percent of northern European patients with GSE carry a particular HLA-DQ alpha beta heterodimer. Studies support the concept that the HLA-DQ gene acts as a dominant gene, and they also found that, in addition to HLA-DQ, a second locus within the major histocompatibility complex (MHC) is involved in the predisposition to GSE in the Dutch population. Genome scans conducted so far suggest that MHC and non-MHC loci collectively contribute to disease susceptibility. Since one, and probably even two, gene(s) from the MHC region itself determine at least 40% to 50% of the genetic predisposition to GSE, it is expected that the other loci each contribute only a little to the total genetic variation. The exact role of these additional genes (i.e., whether they are involved in the initiation or the progression of the disease) remains to be determined.

Brain white-matter lesions in celiac disease: a prospective study of 75 diet-treated patients

OBJECTIVE

Celiac disease (CD), or gluten sensitivity, is considered to be a state of heightened immunologic responsiveness to ingested gluten proteins in genetically predisposed individuals. The gastrointestinal manifestation suggests a severe enteropathy of the small intestine with malabsorption, steatorrhea, and weight loss because of a deranged mucosal immune response. Neurologic complications occur, especially epilepsy, possibly associated with occipital calcifications or folate deficiency and cerebellar ataxia. There have been reports of brain white-matter lesions as an extraintestinal manifestation in Crohn disease and ulcerative colitis but not in CD.

METHODS

In this study, 75 diet-treated mainly pediatric patients with biopsy-proven CD underwent prospectively clinical neurologic examinations, laboratory investigations, electroencephalography, computed tomography, and magnetic resonance imaging. The age range was 2.8 to 24.2 years with a mean of 11.6 years. The mean period of gluten exposure was 2.4 years.

RESULTS

Ten patients had neurologic findings such as febrile seizures, single generalized seizures, mild ataxia, and muscular hypotonia with retarded motor development. No folate deficiency was found. The hippocampal regions showed no abnormalities. Computed tomography did not reveal any cerebral calcifications, but magnetic resonance imaging detected unilateral and bilateral T2-hyperintensive white-matter lesions in 15 patients (20%). There was no correlation between these lesions and dietary compliance or neurologic or electroencephalographic abnormalities. The mean gluten exposure time of these patients was slightly increased (not significant).

CONCLUSIONS

Focal white-matter lesions in the brain may represent an extraintestinal manifestation of CD. They may be ischemic in origin as a result of a vasculitis or caused by inflammatory demyelination. They seem to be more typical of pediatric CD than cerebral calcifications. Their prognostic value is unclear and needs to be elucidated in additional studies. CD should be suggested as a differential diagnosis in children with unclear white-matter lesions even without intestinal symptoms.