Methylation profile of CD247 and FOXP3 genes and frequency of certain HLA-DQ haplotypes in Celiac disease

Background: Celiac disease is an autoimmune disorder that affects the small intestine in people with gluten intolerance. HLA-DQ2 and DQ8 have been associated with Celiac Disease. CD247 is a subunit of the T cell receptor complex and Forkhead box P3 (FOXP3) is a transcription factor involved in the regulation of the immune response. Expression levels of these two markers in various diseases, including autoimmune disorders, are controversial. In this context, we aimed to shed light on the etiopathogenesis of Celiac disease by determining the methylation profile of CD247 and FOXP3 genes, and to calculate the frequency of HLA-DQ haplotypes in this disease. Methods: Methylated and unmethylated copy numbers of the CD247 and FOXP3 genes in samples were calculated using the methylation-specific qPCR method. The records regarding HLA-DQ2 and DQ8 genotypes previously detected from our patients by Real Time PCR and tissue transglutaminase IgA (TTG-IgA) by ELISA, were analyzed. Results: CD247 methylation rate in our patients was significantly lower than in controls. According to the Marsh classification, the methylation level in Marsh type 2-3 patients was statistically lower than in type 1. On the contrary, FOXP3 had a significantly higher methylation rate in the patient group compared to healthy controls, and this gene was also found to be more methylated in Marsh type 2-3 patients than in Marsh type 1. In the patient group, HLA-DQ2 positivity was 82.5% and HLA-DQ8 positivity was 37.5%. Conclusion: The data suggest that CD247 expression is upregulated, whereas FOXP3 expression is downregulated in Celiac disease. Among HLA haplotypes, HLA-DQ2 heterodimer came to the forefront with its frequency in terms of celiac predisposition.