ABSTRACT
Abstract INTRODUCTION: The human T-lymphotropic virus type 1 (HTLV-1) has a single-stranded RNA genome and expresses specific proteins that have oncogenic potential. Approximately 15 to 20 million people worldwide have been infected by this virus. Changes in protein or gene expression are the effects of single nucleotide polymorphisms (SNPs) within the Toll-like receptor 3 (TLR3) gene. The function and efficacy of signal transduction also lead to modified immune responses. The present study aimed to investigate the association of SNPs within TLR3 (rs3775291 and rs3775296) with susceptibility to HTLV-1 infection in Iranian asymptomatic blood donors. METHODS: This study was performed on 100 HTLV-1-infected asymptomatic blood donors and 118 healthy blood donors. Genomic DNA from all participants was purified and then amplified using specific PCR primers. SNPs within TLR3 were evaluated using the restriction fragmentation length polymorphism technique, and the results were analyzed using SPSS software (version 22). RESULTS: The frequencies of the TLR3 (rs3775296) CC, CA, AA genotypes were 70%, 24%, and 6% in the patient group, and 50.8%, 44.9%, and 4.2% in the control group, respectively. There was a significant difference in the frequency distribution of TLR3 (rs3775296) genotypes and alleles, but not in the frequency distribution of TLR3 (rs3775291) genotypes between the patient and control groups. CONCLUSIONS: The TLR3 SNP rs3775296 was significantly associated with HTLV-1 infection and may be a protective factor against this viral infection.
Subject(s)
Humans , Male , Female , Adult , Blood Donors/statistics & numerical data , Human T-lymphotropic virus 1/genetics , HTLV-I Infections/genetics , Polymorphism, Single Nucleotide/genetics , Toll-Like Receptor 3/genetics , HTLV-I Infections/diagnosis , Case-Control Studies , Genetic Predisposition to Disease , Genotype , Iran , Middle AgedABSTRACT
Abstract Introduction: Host genetics is recognized as an influential factor for the development of dengue disease. Objective: This study evaluated the association of dengue with the polymorphisms rs8192284 for gene IL6R, rs3775290 for TLR3, and rs7248637 for DC-SIGN. Materials and methods: Of the 292 surveyed subjects, 191 were confirmed for dengue fever and the remaining 101 were included as controls. The genotypes were resolved using polymerase chain reaction and restriction fragment length polymorphism (PCR- RFLP). In an attempt to determine the risk (Odds Ratio) of suffering dengue fever, data were analyzed using chi-square for alleles and logistic regression for both genotypes and allelic combinations. Confidence intervals were set to 95% for all tests regardless of the adjustment by either self-identification or ancestry. Results: For Afro-Colombians, the allele rs8192284 C offered protection against dengue [OR=0.425,(0.204-0.887), p=0.020]. The alleles rs7248637 A and rs3775290 A posed, respectively, an increased risk of dengue for Afro-Colombians [OR=2.389, (1.170-4.879), p=0.015] and Mestizos [OR=2.329, (1.283-4.226), p=0.005]. The reproducibility for rs8192284 C/C [OR=2.45, (1.05-5.76), p=0.013] remained after adjustment by Amerindian ancestry [OR=2.52, (1.04-6.09), p=0.013]. The reproducibility for rs3775290 A/A [OR=2.48, (1.09-5.65), p=0.033] remained after adjustment by European [OR=2.34, (1.02-5.35), p=0.048], Amerindian [OR=2.49, (1.09-5.66), p=0.035], and African ancestry [OR=2.37, (1.04-5.41), p=0.046]. Finally, the association of dengue fever with the allelic combination CAG [OR=2.07, (1.06-4.05), p=0.033] remained after adjustment by Amerindian ancestry [OR=2.16, (1.09-4.28), p=0.028]. Conclusions: Polymorphisms rs8192284 for IL6R, rs3775290 for TLR3, and rs7248637 for DC-SIGN were associated with the susceptibility to suffer dengue fever in the sampled Colombian population.
Resumen Introducción. La genética del huésped se reconoce como un factor que influye en el desarrollo del dengue. Objetivo. Este estudio evaluó la asociación del dengue con los polimorfismos rs8192284 del gen IL6R, rs3775290 del TLR3 y rs7248637 del DC-SIGN. Materiales y métodos. De los 292 sujetos encuestados, en 191 se confirmó la presencia de fiebre por dengue y los restantes 101 se incluyeron como controles. Los genotipos se resolvieron mediante reacción en cadena de la polimerasa y polimorfismos en la longitud de los fragmentos de restricción (PCR-RFLP). En un intento por determinar el riesgo de sufrir dengue, los datos se analizaron mediante la prueba de ji al cuadrado para los alelos y la regresión logística para los genotipos y las combinaciones alélicas. Los intervalos de confianza se calcularon a 95 % para todas las pruebas independientemente ajustadas por autoidentificación o componente genético ancestral. Resultados. En los afrocolombianos, el alelo C rs8192284 ofreció protección contra el dengue (OR=0,425; 0,204-0,887, p=0,020). Los alelos A rs7248637 y Ars3775290 plantearon un mayor riesgo de dengue para los afrocolombianos (OR=2,389; 1,170- 4,879; p=0,015) y los mestizos (OR=2,329; 1,283-4,226: p=0,005), respectivamente. La reproducibilidad para rs8192284 C/C (OR=2,45; 1,05-5,76; p=0,013) permaneció después del ajuste por el componente genético ancestral amerindio (OR=2,52; 1,04- 6,09; p=0,013). La reproducibilidad del rs3775290 A/A (OR=2,48; 1,09-5,65; p=0,033) permaneció después del ajuste por el componente europeo (OR=2,34; 1,02-5,35; p=0,048), el amerindio (OR=2,49; 1,09- 5,66; p=0,035), y el africano (OR=2,37; 1,04- 5,41; p=0,046). Por último, la asociación del dengue con la combinación alélica CAG (OR=2,07; 1,06-4,05; p=0,033) permaneció después del ajuste por el componente genético amerindio (OR=2,16; 1,09-4,28;p=0,028). Conclusión. Los polimorfismos rs8192284 en IL6R, rs3775290 en TLR3 y rs7248637 en DC-SIGN, se asociaron con la propensión a sufrir dengue en una muestra de población colombiana.
Subject(s)
Adult , Female , Humans , Male , Polymorphism, Restriction Fragment Length , Cell Adhesion Molecules/genetics , Receptors, Cell Surface/genetics , Receptors, Interleukin-6/genetics , Dengue/genetics , Lectins, C-Type/genetics , Toll-Like Receptor 3/genetics , Genetic Variation , Colombia , Genetic Predisposition to DiseaseABSTRACT
Background & objectives: Hepatitis C virus (HCV) induces an immune response of the host, manifested by the formation of anti-HCV antibodies mediated by adaptive and innate immunity. Toll-like receptors (TLRs) play a pivotal role in innate immunity system. This study was aimed to investigate the promoter region polymorphism and expression of TLR3 gene in patients with chronic HCV infection. Methods: Patients with chronic HCV infection (N=180) and an equal number of age-sex matched controls were included in the study. Patients positive for HCV-RNA were subjected to analysis of TLR3 polymorphism by direct sequencing of PCR products verified by comparing with the sequences reported in the National Centre for Biotechnology Information (NCBI) database (accession number: NT 022792). Expression of TLR3 gene was analyzed by semiquantitative RT-PCR using housekeeping β-actin gene as the internal control. Results: Polymorphisms at position -288G/A and -705A/G were identified. The results were significant in -705 allele (P=0.004) OR 2.79(1.46-5.42) and were associated with high risk of HCV infection. In silico sequence analysis showed the presence of ectropic viral integration site 1 encoded factor, in which G at -705 results in the loss of this site. The -7C/A polymorphism was not seen in our study cohort. The expression of TLR3 was upregulated in chronic HCV patients compared to healthy controls. Interpretation & conclusions: Polymorphism in the -705A/G allele at the promoter region of the TLR3 gene may predispose individual to HCV infection. However association of TLR3 expression with polymorphism of TLR3 promoter was not found.