Análise do perfil sorológico, clínico, sociodemográfico e da influência dos polimorfismos -174 G/C (rs1800795) do gene IL-6 e -308 G/A (rs1800629) do gene TNFα em pacientes acometidos por febre Chikungunya no estado do Ceará

Abstract

The chikungunya fever (CHIKF) is a viral disease of acute onset, characterized by cause arthralgia involving one or more joints. The disease is caused by infection with Chikungunya virus (CHIKV) and affects thousands of people annually. Some affected individuals persist with joint symptoms for months or years, giving rise to the chronic phase of the disease. Factors inherent to both the microorganism and the host may be involved in susceptibility, progression or protection against CHIKF. Among the host factors, stand out the type of immune response and genetic factors, such as single nucleotide genetic polymorphisms (SNPs) in cytokine genes. The present study aimed to analyze the sociodemographic and serological profile, the prevalence and influence of SNPs -174 G/C (rs1800795) of the IL-6 gene and -308 G/A (rs1800629) of the TNFα gene in control patients and affected individuals by CHIKF in the state of Ceará. Serological ELISA tests and DNA extraction were performed. All samples were genotyped using the real-time PCR technique for variants in the IL-6 and TNFα genes. Statistical analyzes were performed using the Bioestat 5.0 software and included Fisher's Exact Test and Chi-square (x²), considering p < 0.05 as the level of statistical significance. A total of 313 subjects composed the study, of which 102 were allocated to the positive cases (PC) group, 182 to the negative control (NC) group and 29 were asymptomatic (ASY). The arthralgia was present in 100% of the cases in the PC group, statistically significant differences (p < 0.05) were evidenced for joint pain intensities between male and female genders. A higher frequency of the G/A genotype of the SNP -308 G/A in the TNFα gene was observed in the PC group in relation to the NC, as well as a higher frequency of the A allele. The mutant allele A was also identified more frequently in the PC group in compared to the ASY group. However, without statistical significance. For the -174 G/C SNP in the IL-6 gene, a higher frequency of the G/C heterozygote was observed in the NC group in relation to the PC, as well as the C mutant allele was more frequent in the NC group in relation to the PC and in the NC group compared to ASY. However, with no statistical significance. On the other hand, statistically significant differences (p < 0.05) were observed between the allele frequencies obtained for the variants analyzed in this study in relation to the distributions found in the genomic association studies for other populations