Chronic Chikungunya Arthritis in Northeastern Brazil: An Association with Very Severe Joint Pain and Lack of Correlation with IL-6 and TNFα Gene Polymorphisms

Chikungunya fever (CHIKF) affects thousands of people annually. Therefore, aspects involved in the pathogenesis of the disease must be further explored. In this study, we assessed the development of chronic chikungunya arthritis (CCA) and the single-nucleotide polymorphisms (SNPs) -174 G/C in the interleukin-6 (IL-6) gene and -308 G/A in the tumor necrosis factor alpha (TNFα) gene on CHIKF development in a population from Northeastern Brazil. A total of 313 blood and serum samples were collected. Of these, 102 were included in the cases group, 182 were included in the control group, and 29 were incorporated in the asymptomatic group. The DNA extraction and genotyping across real-time quantitative polymerase chain reaction (RT-qPCR) were performed. The data showed that 71.6% of individuals who had CHIKF developed CCA. A significant increase in CCA development was observed in females, and very severe joint pain was associated with increased risk of CCA. In contrast, we did not identify significant associations between the SNPs and CHIKF development. Our data indicate that females and individuals who develop very severe joint pain have an increased risk for CCA and highlight the lack of correlation of SNPs in the IL-6 and TNFα genes with CHIKF in the studied population.