Association of -1087 IL10 and -308 TNFA gene polymorphisms with serological markers of coeliac disease

Understanding the Genetic Basis of Celiac Disease: A Comprehensive Review

Celiac disease is an immune-mediated enteropathy with typical symptoms of weight loss, abdominal bloating, diarrhea, vomiting, or constipation. Many shreds of evidence show that CeD is hereditary in origin and various biochemical pathways have been connected to its etiology. Numerous genes from different physiological pathways have been investigated in the last few decades, however a comprehensive analysis is required to address the gaps and provide a more integrated understanding of how these genetic factors contribute to the pathogenesis of disease. Present study attempts to summarize the historical and up-to-date findings to understand the role of genetics in Celiac disease. The literature was searched from sources such as PubMed and Google Scholar to analyze studies conducted on celiac disease from the years 1995 to 2024. Term maps were created to examine the frequency of studies related to various terms to understand the major focus of the studies till date. The study also concise the different genetic polymorphisms studied in a table to understand the role of genetics in celiac diseases. Early studies on celiac disease primarily focused on its pathophysiology, prevalence, and general aspects, with limited attention to genetics. However, recent studies have increasingly emphasized the genetic basis of the disease and highlighting the involvement of various pathways like inflammation, T-cell differentiation and activation, epithelial barrier function, stress and apoptosis pathways. However, present study indicate that most current research predominantly focus on cytokines, specifically the TNF alpha gene. Consequently, there is a need for additional research to gain a more comprehensive understanding of the genetics of celiac disease.

ASSOCIATIONS OF IL-6 -174G>C AND IL-10 -1082A>G POLYMORPHISMS WITH SUSCEPTIBILITY TO CELIAC DISEASE: EVIDENCE FROM A META-ANALYSIS AND LITERATURE REVIEW

BACKGROUND

There has been little evidence to suggest that the IL-6 -174G>C and IL-10 -1082A>G polymorphisms are significantly associated with susceptibility to celiac disease. Thus, we performed the present meta-analysis to explore the potential association between these polymorphisms and celiac disease risk.

METHODS

Eligible studies were searched in PubMed, Medline, Embase, Web of Science and CNKI database up to April 20, 2019. Odds ratios with 95% confidence interval were calculated to assess the potential associations. Moreover, we performed the heterogeneity, sensitivity, and publication bias tests to clarify and validate the pooled results.

RESULTS

Overall, nine case-control studies involving five studies with 737 cases and 1,338 control on IL-6 -174G>C polymorphism and four studies with 923 cases and 864 controls on IL-10 -1082A>G polymorphism were selected. The pooled ORs showed that the IL-6 -174G>C and IL-10 -1082A>G polymorphisms were not significantly associated with increased risk of celiac disease under all five genetic models. There was no publication bias.

CONCLUSION

To the best of our knowledge, this is the first meta-analysis summarizing all of the available studies on the association of IL-6 -174G>C and IL-10 -1082A>G polymorphisms with celiac disease. Our results suggest that the IL-6 -174G>C and IL-10 -1082A>G polymorphisms may not be associated with increased risk of celiac disease. Moreover, large and well-designed studies are needed to fully describe the association of IL-6 -174G>C and IL-10 -1082A>G polymorphisms with celiac disease.

ASSOCIATION OF TNF- α-308G>A POLYMORPHISM WITH SUSCEPTIBILITY TO CELIAC DISEASE: A SYSTEMATIC REVIEW AND META-ANALYSIS

BACKGROUND

There is increasing evidence to show that TNF-α -308G>A polymorphism may be a risk factor for celiac disease, but the results are inconsistent.

OBJECTIVE

Thus, we aimed to perform a meta-analysis involving published studies up to January 2019 to elucidate the association.

METHODS

To assess the effect of TNF-α -308G>A polymorphism on celiac disease susceptibility, we searched PubMed, ISI Web of Knowledge, Chinese National Knowledge Infrastructure (CNKI) databases to identify eligible studies, without restriction. Summary odds ratios (ORs) and 95% confidence intervals (CIs) were used to evaluate the susceptibility to celiac disease.

RESULTS

A total of 11 studies with 1147 cases and 1774 controls were selected for this meta-analysis. The pooled results indicated that TNF-α -308G>A polymorphism was associated with increased risk of celiac disease (A vs G: OR=2.077, 95% CI=1.468-2.939, P=≤0.001; AA vs GG: OR=8.512, 95% CI=3.740-19.373, P=≤0.001; AA+AG vs GG: OR=1.869, 95% CI=1.161-3.008, P=0.010; and AA+AG vs GG: OR=4.773, 95% CI=3.181-7.162, P≤0.001). Subgroup analysis by ethnicity also revealed significant association in Caucasians. In addition, there was a significant association between TNF-α -308G>A polymorphism and celiac disease risk in Italy, Spain and PCR-FRLP group studies.

CONCLUSION

Our meta-analysis suggests that the TNF-α -308G>A polymorphism plays an important role in celiac disease susceptibility. However, our results are still needed to strengthen by further studies in different ethnicities and larger sample sizes.

IL10 promoter haplotypes may contribute to altered cytokine expression and systemic inflammation in celiac disease

Celiac disease (CD) is an autoimmune/inflammatory condition triggered by dietary gluten intake in genetically predisposed individuals. Though associations with MHC class II HLA-DQ2 or -DQ8 are the primary and necessary genetic predisposition for CD, >97% of genetically predisposed individuals never develop CD. Cytokines were measured in the serum of CD patients and controls. Possible associations with IL10 promoter variants were investigated. Cytokine expression from PBMCs was monitored in response to gluten exposure, or CD3/TCR complex stimulation in the absence or presence of recombinant IL-10. Serum cytokines varied between patients with CD at the time of diagnosis, after dietary elimination of gluten, and healthy controls. Serum IL-17A reflected disease activity. Reduced IL-10 serum levels and altered IL-10 expression by PBMCs coincided with IL10 promoter haplotypes that encode for "low" IL-10 expression (ATA). Increased prevalence of ATA IL10 promoter haplotypes and subsequently reduced IL-10 expression may be an immunological cofactor in individuals genetically predisposed for the development of CD. Resulting cytokine imbalances may be utilized as disease biomarkers in CD.

TNF-α -308 G > A (rs1800629) Polymorphism is Associated with Celiac Disease: A Meta-analysis of 11 Case-Control Studies

Celiac disease (CD) remains one of the most significant autoimmune diseases worldwide. The pathogenesis of CD is not clearly understood and is probably attributed to genomic variations and host genetic make-up. Case-control and cohort studies of the association between the TNF-α -308 G > A (rs1800629) polymorphism and CD susceptibility have yielded inconsistent results. In this study, PubMed, EMBASE, and Google Scholar web-databases were searched for pertinent reports showing association of TNF-α -308 G > A gene with CD risk. A total of eleven reports involving 1774 controls and 1147 CD cases were included. Significant associations in four genetic models, viz. variant allele (A vs. G: p = 0.001; OR = 2.051, 95% CI = 1.452-2.895), variant homozygous (AA vs. GG: p = 0.001; OR = 6.626, 95% CI = 3.569-12.300), recessive (AA vs. GG + AG: p = 0.001; OR = 4.766, 95% CI = 3.177-7.152) and dominant (AA + AG vs. GG: p = 0.008; OR = 1.910, 95% CI = 1.181-3.088) were found in comparison with wild type homozygous GG genotype. However, heterozygous genetic model did not show any association. Sensitivity analysis revealed stable and statistically robust results. Our results suggest that TNF-α -308 G > A gene polymorphism significantly contributes to CD susceptibility.

Molecular mechanisms of the adaptive, innate and regulatory immune responses in the intestinal mucosa of celiac disease patients

Celiac disease is a complex genetic disorder that affects the small intestine of genetically predisposed individuals when they ingest gluten, a dietary protein. Although several genome screens have been successful in identifying susceptibility loci in celiac disease, the only genetic contributors identified so far are the human leukocyte antigen (HLA)-DQ2/DQ8 molecules. One of the most important aspects in the pathogenesis of celiac disease is the activation of a T-helper 1 immune response, when the antigen-presenting cells that express HLA-DQ2/DQ8 molecules present the toxic gluten peptides to reactive CD4(+) T-cells. Recently, new insights into the activation of an innate immune response have also been described. It is generally accepted that the immune response triggers destruction of the mucosa in the small intestine of celiac disease patients. Hence, the activation of a detrimental immune response in the intestine of celiac disease patients appears to be key in the initiation and progression of the disease. This review summarizes the immunologic pathways that have been studied in celiac disease thus far, and will point to new potential candidate genes and pathways involved in the etiopathogenesis of celiac disease, which should lead to novel alternatives for diagnosis and treatment.

Evaluation of 6 candidate genes on chromosome 11q23 for coeliac disease susceptibility: a case control study

Background

Recent whole genome analysis and follow-up studies have identified many new risk variants for coeliac disease (CD, gluten intolerance). The majority of newly associated regions encode candidate genes with a clear functional role in T-cell regulation. Furthermore, the newly discovered risk loci, together with the well established HLA locus, account for less than 50% of the heritability of CD, suggesting that numerous additional loci remain undiscovered. Linkage studies have identified some well-replicated risk regions, most notably chromosome 5q31 and 11q23.

Methods

We have evaluated six candidate genes in one of these regions (11q23), namely CD3E, CD3D, CD3G, IL10RA, THY1 and IL18, as risk factors for CD using a 2-phase candidate gene approach directed at chromosome 11q. 377 CD cases and 349 ethnically matched controls were used in the initial screening, followed by an extended sample of 171 additional coeliac cases and 536 additional controls.

Results

Promotor SNPs (-607, -137) in the IL18 gene, which has shown association with several autoimmune diseases, initially suggested association with CD (P < 0.05). Follow-up analyses of an extended sample supported the same, moderate effect (P < 0.05) for one of these. Haplotype analysis of IL18-137/-607 also supported this effect, primarily due to one relatively rare haplotype IL18-607C/-137C (P < 0.0001), which was independently associated in two case-control comparisons. This same haplotype has been noted in rheumatoid arthritis.

Conclusion

Haplotypes of the IL18 promotor region may contribute to CD risk, consistent with this cytokine's role in maintaining inflammation in active CD.

Interleukin 10 and tumor necrosis factor-alpha genotypes in rheumatoid arthritis--association with clinical response to glucocorticoids

OBJECTIVE

There are dysregulated levels of interleukin 10 (IL-10) and tumor necrosis factor-alpha (TNF-alpha) in rheumatoid arthritis (RA), and their role in the disease is controversial. We analyzed the association of functional polymorphisms of IL-10 and TNF-alpha with susceptibility and disease characteristics at the time of diagnosis, and we also evaluated their possible use as predictors of clinical response to treatments.

METHODS

Patients with recent-onset RA (n = 162) and healthy controls (n = 373) were genotyped for -1082 IL-10 and -308 TNF-alpha polymorphisms and data were related to clinical and immunological measurements of patients at the time of diagnosis. Response to treatment after 6 months was determined in 125 patients by the absolute change in Disease Activity Score (DAS28) and the American College of Rheumatology criteria for improvement.

RESULTS

We found a reduced frequency of the low IL-10 producer genotype (-1082AA) in patients with RA compared to controls (26.5% vs 38.9%; p = 0.006), while it is a risk factor for anticyclic citrullinated peptide antibodies (anti-CCP) positivity (p = 0.028). Evaluation of clinical response to treatments indicated that carriage of the high IL-10 genotype was associated with a favorable outcome (p = 0.009), specifically to prednisone therapy (p = 0.0003). No significant effects were observed with TNF-alpha polymorphism alone; however, in combination with the IL-10 genotype, it increased the strength of these associations.

CONCLUSION

Results show an association between the low IL-10 producer genotype and protection from RA; nevertheless, when other specific genetic and/or environmental factors trigger onset of RA, this genotype may predispose to development of anti-CCP+ RA disease with reduced response to prednisone treatment.

Association of IL-10 and TNFalpha genotypes with ANCA appearance in ulcerative colitis

The appearance of autoantibodies is a common characteristic of ulcerative colitis (UC). Specifically, anti-neutrophil cytoplasmic antibodies (ANCA) are the most prevalent in this disease and their synthesis may be genetically conditioned. The aim of the present study was to test the influence on appearance of autoantibodies of IL-10 and TNFalpha genes promoter polymorphisms, which control cytokine levels. Genetic polymorphisms of TNFalpha (-308 G/A) and IL-10 (-1082 G/A) and ANCA and anti-goblet cells antibodies (GAB) presence were determined in 99 UC patients. The -308A* allele and -308AA/AGTNFalpha genotypes (high producer), clearly correlated with ANCA positivity (p = 0.004 and p = 0.007, respectively). Additionally, homozygous carriage of the -1082A*IL-10 allele (low producer) significantly associated with ANCA presence (p = 0.007). Furthermore, combination of both genotypes (low IL-10/high TNFalpha producer genotype) had a greater influence on ANCA positivity than each individual genotype (p = 0.008). ANCA production in UC thus appears to be conditioned by IL-10 and TNFalpha genotypes.

IL-10 polymorphisms are associated with early-onset celiac disease and severe mucosal damage in patients of Caucasian origin

PURPOSE

Polymorphisms in cytokine genes can determine their level of expression and affect the phenotypic expression of immunomediated diseases, such as celiac disease (CD). We thus evaluated cytokine polymorphism prevalence in CD patients and population controls, and assessed the correlation between specific polymorphisms and celiacs' clinical characteristics.

METHODS

155 CD patients and 202 population controls were enrolled in the study. Cytokine polymorphisms (TNFalpha -308 and -238, IL-1beta -511 and +3954, IL-1b RN + 2018, IL-6 -174, IL-10 -1082, -819 and -592, TGFbeta1 + 29 and +74, IFN-gamma + 874) and HLA class II alleles were determined by sequence-specific primer polymerase chain reaction or restriction fragment length polymorphism analysis. Duodenal histology was classified using Marsh's criteria. Variables significantly associated with CD patients' characteristics were identified by multivariate logistic regression analysis.

RESULTS

A significantly higher frequency of -308 TNFalpha polymorphism was observed in CD patients compared to the entire population control group, although no difference was detected when population controls were stratified according to HLA class II. Among celiacs, early onset of the disease (< or =2 year old) and the presence of a severe intestinal lesion (Marsh 3C) were significantly associated with the -1082 A/A IL-10 genotype which corresponds to a low producer phenotype (OR 3.28, 95% CI 1.49-7.19 and OR 2.60, 95% CI 1.04-6.49, respectively).

CONCLUSION

The association between IL-10 genotypes and both histological severity at diagnosis and age of onset could be related to an alteration in cytokine balance, and supports the idea that the various clinical manifestations of the disease could be determined by a different genetic background.

Interleukin-10 haplotypes in Celiac Disease in the Spanish population

Background

Celiac disease (CD) is a chronic disorder characterized by a pathological inflammatory response after exposure to gluten in genetically susceptible individuals. The HLA complex accounts for less than half of the genetic component of the disease, and additional genes must be implicated. Interleukin-10 (IL-10) is an important regulator of mucosal immunity, and several reports have described alterations of IL-10 levels in celiac patients. The IL-10 gene is located on chromosome 1, and its promoter carries several single nucleotide polymorphisms (SNPs) and microsatellites which have been associated to production levels. Our aim was to study the role of those polymorphisms in susceptibility to CD in our population.

Methods

A case-control and a familial study were performed. Positions -1082, -819 and -592 of the IL-10 promoter were typed by TaqMan and allele specific PCR. IL10R and IL10G microsatellites were amplified with labelled primers, and they were subsequently run on an automatic sequencer. In this study 446 patients and 573 controls were included, all of them white Spaniards. Extended haplotypes encompassing microsatellites and SNPs were obtained in families and estimated in controls by the Expectation-Maximization algorithm.

Results

No significant associations after Bonferroni correction were observed in the SNPs or any of the microsatellites. Stratification by HLA-DQ2 (DQA1*0501-DQB1*02) status did not alter the results. When extended haplotypes were analyzed, no differences were apparent either.

Conclusion

The IL-10 polymorphisms studied are not associated with celiac disease. Our data suggest that the IL-10 alteration seen in patients may be more consequence than cause of the disease.

The genetic basis of autoantibody production

Many autoimmune diseases are characterized by autoantibody subsets that are associated with specific clinical manifestations. The primary genetic associations of these autoantibodies are with MHC genes, most specifically HLA class II, which in many instances better explain the HLA association of the disease per se. It is noteworthy that certain genes and haplotypes, notably HLA-DRB1*0301, DQA1*0501, DQB1*0201 in Caucasians and DRB1*0405, DQA1*03, DQB1*0401 in Asians, as well as PTPN22, seem to be associated with a variety of autoimmune diseases. On the other hand, others are more disease specific (HLA-DRB1*11 for systemic sclerosis and HLA-DRB1 alleles encoding the "shared epitope" in RA) as well as non MHC genes, such as FcyRIIa and IIIa in SLE, the beta2 glycoprotein I gene in the aPL syndrome, and the TSHR gene in Graves' disease). Autoantibody responses also are influenced by the presence of specific MHC and non-MHC genes which may not be associated with the disease per se. These novel associations offer new clues not only to pathogenesis but also to potential therapeutic targets.

TNFalpha, IFNgamma and IL-10 gene polymorphisms in a sample of Sicilian patients with coeliac disease

BACKGROUND

Coeliac disease is associated with DQ2 and DQ8 alleles, but other genes also confer an additional genetic risk.

AIMS

Defining whether the genetic profiles of interleukin-10, tumour necrosis factor alpha and interferon gamma are associated with an increased coeliac disease risk.

PATIENTS AND METHODS

The functionally gene polymorphisms of tumour necrosis factor alpha (-308G/A), interferon gamma (+874T/A) and interleukin-10 (-1082G/A) were typed using sequence specific primer-polymerase chain reaction in 110 Sicilian coeliac disease patients and in 220 Sicilian healthy controls.

RESULTS

No differences in genotype frequencies of interleukin-10 polymorphisms were found between coeliac disease patients and healthy controls. A significant increase of -308A (p<0.033; OR: 1.72; CI: 1.27-2.33) and of +874T (p: 0.0045; OR: 3.02; CI: 1.47-6.21) allele frequencies, both in hetero- and homozygosis, was observed in coeliac patients in comparison with healthy controls. In addition, simultaneous significant higher percentages of -308A and +874T alleles (p: 0.0066; OR: 2.33; CI: 1.42-3.82) as well as simultaneous significant lower percentages of -308A and +874T alleles (p: 0.003; OR: 0.23; CI: 0.10-0.60) were observed in coeliac patients compared with healthy controls.

CONCLUSIONS

Genetically determined higher frequencies of -308A tumour necrosis factor alpha and +874T interferon gamma alleles, both in hetero and in homozygosis and mostly whether simultaneous, may play a role in predisposing to gluten intolerance. Subjects positive for -308A tumour necrosis factor alpha and +874T interferon gamma alleles have an increased risk for coeliac disease.

Association of the -159 CD14 gene polymorphism and lack of association of the -308 TNFA and Q551R IL-4RA polymorphisms with severe chronic periodontitis in Swedish Caucasians

BACKGROUND

Severe forms of periodontitis are suggested to have a genetic basis.

OBJECTIVE

The aim of the present investigation was to study the association of gene polymorphisms related to some immune regulation components (G-308A TNFA, Q551R IL-4RA and C-159T CD14) with severe chronic periodontitis.

MATERIALS AND METHODS

Sixty patients (aged 36-74 years; mean 54.5+/-8.5) with severe and generalized chronic periodontitis were included. The patients exhibited bone loss >50% at all teeth. Thirty-nine periodontally healthy subjects between 35 and 78 years of age (mean 51.0+/-10.9) were recruited as controls. DNA was isolated from peripheral blood cells and genotyping was performed by combination of PCR and restriction endonuclease mapping.

RESULTS

While gene polymorphisms for TNFA and IL-4RA did not show any association with severe chronic periodontitis, the analysis of the -159 CD14 gene polymorphism revealed significant differences between test and control groups. The proportion of subjects that exhibited the TT genotype was significantly smaller in the group with severe periodontitis than in periodontal healthy group (p=0.028; Fisher's exact test). The C allele carriage was 90% in the periodontitis group and significantly higher than in the healthy control group (72%).

CONCLUSION

It is suggested that the -159 CD14 gene polymorphism is associated with chronic periodontitis in Caucasian subjects of a north European origin.