Prevalence of polymorphism of the TLR 9 type gene in patients with infectious mononucleosis caused by Epstein-Barr virus

Annotation. The prevalence of polymorphism -1486 T/C of TLR-9 gene in 52 patients with infectious mononucleosis (IM) caused by the Epstein-Barr virus was studied. Based on the results obtained, three main genotypes -1486 T/C of the gene TLR-9-TT, TC, CC, were identified. The study of the frequency of occurrence of individual genotypes in patients with IV revealed dominance of CC and TT genotypes in comparison with the control group. The study of the frequency distribution of the -1486 T/C polymorphism of the TLR-9 gene for different genotypes showed the specificity of the changes for the CC genotype in patients with IM and the absence of such changes for the TT and TC genotypes. Aim of research. To establish the frequency of the polymorphism -1486 T/C of the TLR-9 gene in patients with IM caused by the Epstein-Barr virus. Materials and methods. A study to determine the polymorphism -1486 T/C of the TLR-9 gene was conducted in 52 patients with IM. Among them, women - 31 (59,6%), men - 21 (40,4%) at the age of 18 to 34 years. The control group for studying the prevalence of the polymorphism -1486 T/C of the TLR-9 gene was 40 healthy donors. The mean age was 24,2±2,4 years, with a range from 18 to 44 years. To detect DNA VEB using the reverse transcription PCR method with hybridization-fluorescent detection of amplification products, Amplisens (Russia) reagent kits were used. The polymorphic region -1486 T/ C, rs187084 of the TLR9 gene was studied by real-time PCR amplification by determining the length of the restriction fragments-PCR using Ncol restriction enzyme and oligonucleotide primers. Results. An analysis of the results of polymorphism -1486 T/C of the TLR-9 gene made it possible to identify three main genotypes - TT, TC, CC. The allotment frequency of the discovered -1486Т/С SNP genotypes of the gene TLR-9 in patients with ІМ was the following: ТТ genotype – 17 % (9 patients), ТС – 46 % (24 patients) and СС – 37 % (19 patients). In patients of the control group wild type of TT genotype was found in 40,0% (16 patients), heterozygous ТС genotype - in 45,7% (18 patients), while homozygous СС genotype was found in 14,3% (6 patients). An investigation of the frequency of occurrence of individual genotypes revealed the dominance of CC and TT genotypes in comparison with the heterozygous genotype of the TC. The study of the frequency distribution of the -1486 T/C polymorphism of the TLR-9 gene for different genotypes showed the specificity of the changes for the CC genotype in patients with IM and the absence of such changes for the TT and TC genotypes. Analyzing the occurrence frequencies allotment of -1486 Т/С genotypes of the gene TLR-9 in patients with ІМ statistically significant differences of the level р0,1). According to the calculated index of the odds ratio presence of homozygous CC genotype in the genome of the patients with IM is specific for the patients with IM (CI:1,16-9,2 і OR=3,26, consequently) allowing to estimate it as a positive association in comparison with the received indices for homozygous TT genotype (CI:0,12-0,82 і OR=0,31, consequently) and heterozygous ТС genotype (CI:0,46-2,4 і OR=1,05), which are estimated as a negative TT genotype association with IM and absence of associations with IM for TC genotype. Our study on polymorphism -1486 TLR-9 C/C revealed a correlation with the disease of IM, which confirms the important role of TLR-mediated signaling in the pathogenesis of EBV infection. Investigation of polymorphism among the receptors involved in virus recognition is necessary to determine the genetic background associated with the risk of infection, the course of the disease and the possible consequences of MI. This will allow to identify risk groups among patients and to conduct timely therapy. Conclusions. 1. It was proved that in patients with IM, the polymorphism -1486 T/C of the gene TLR-9 was detected more reliably than in the control group. 2. Distribution of frequency of occurrence of polymorphism-1486 Т/С of gene TLR-9 allowed to reveal association of genotype СС with manifest forms of IM