Immuno-genetic Study of the clinical Role of CTLA4( +49 A/G rs231775) Polymorphisms and Soluble CTLA4 in Celiac Disease patients

Abstract

Background

Celiac disease (CD) is a rare condition where a genetic susceptibility and the intake of gluten-containing foods like  Wheat, Barley, and Rye are the primary causes of autoimmune reactions that impact the Gut and other organs. For decades, Celiac disease's pathogenesis has been studied and linked to other human autoimmune diseases . Numerous variables, such as genetic, environmental, and local immunological problems, are contributing to the disease's genesis.

OBJECTIVES

This study investigates the correlation between polymorphisms in CTLA4(+49A/G rs231775) with the progression and intensity of CD in patients. also Explore the correlation between  CTLA4 SNPs and soluble CTLA-4 (sCLLA-4) serum levels on the active progression of CD patients.

MATERIALS AND METHODS

The current investigation identified celiac disease among of sixty Iraqi participants aged above 18 years were included in a case-control study, were divided into two groups: 30 individuals who participated as the control group( they had negative endoscopy and serological test for CD ) and  a  patient group included 30 individuals, and they were categorized into 3 groups: the Newly Diagnosed group, the Gluten-Free Diet group, and Non-Gluten Free Diet group. Each one of these groups included (10) patients. Samples were obtained from two Baghdadi hospitals.: Imameinkadhimein Medical City, Digestive and Liver Diseases Teaching Hospital /Medical City during the period (February to July  2024).Using a serum sample to measure soluble CTLA-4 by enzyme linked immune sorbent (ELISA) assay, For CTLA-4 genotyping, Human DNA extracted out of samples of whole blood of CD  patients using DNA extraction kit, then conventional PCR was employed for (CTLA-4)gene amplification with specific primers, the products of PCR were undergone gel electrophoresis and the results were carried out for DNA sequencing and examined for the presence of the polymorphism CTLA4 (+49A/G rs231775.

RESULTS

The results obtained revealed the predominance of females (35) than males(25) among the CD patients and statistical significance of the difference between them at (P=0.02). High serum sCTLA-4 concentrations were observed in the majority of the Newly Diagnosed and Non-Gluten Free Diet groups , compared to low concentrations in Gluten Free Diet group and normal controls  with the difference between them being statistically significant at p < 0.001**.

the results of gene amplification and genotyping, the results of the current investigation indicated that  the polymorphism of CTLA4 (+49G/A rs231775 ) had three genotypes in CD patients, they were (GA, AA, and GG), the prevalence of the genotype (AA) percentage in patients with CD is lower than that of healthy people . In contrast, the prevalence of the genotype (AG) is higher in CD patients  compared to control  people and the statistical significance of the difference between them at (P=0.015). On the other hand, the data about the serum levels of sCTLA-4 to CTLA-4 (rs231775) genotypes and alleles demonstrated that A significant difference was found at P-value = (0.039) between sCTLA-4 and CTLA-4 rs231775 alleles.

Conclusion: According to the results of this study strongly suggest  that sCTLA-4 production is regulated by Gluten's presence or absence in the diet, which may have an immunomodulatory effect on the functions of cytotoxic T lymphocytes. Thus, we demonstrated that CTLA4 (rs231775) Polymorphisms changing the protein's actual function (sCTLA-4) & The CTLA4 (+49A/G rs231775) SNP's (AG) genotype is one of the risk factors for the development of celiac disease .