Participação das citocinas Interleucina-12, Interferon-γ, Interleucina-4 e Interleucina-10 e investigação de polimorfismos nos genes do INF-γ (IFNG+874) e da IL-10 (IL10-1082) na malária causada por Plasmodium vivax

Abstract

The malaria immune response is complex, and the activation and regulation mechanisms of the efector and memory T cells remain unclear. In this study, we determined seric levels of Interferon-γ (IFN-γ), Interleukin 10 (IL-10), Interleukin-4 (IL-4) and Interleukin-12 (IL-12) in individuals infected by Plasmodium vivax. We investigated polymorphisms in IFN-γ (IFNG+874) and IL-10 (IL10-1082) genes and their association with seric levels and parasite density. Concentrations of IFN-γ, IL-10, IL-4 and IL-12 were detected by ELISA, and IFNG+874 and IL10- 1082 polymorphisms genotyping were investigated by allele-specific oligonucleotide polymerase chain reaction (ASO-PCR) and PCR-RFLP (restriction fragment length polymorphism) methods, respectively. We detected increased levels of IFN-γ and IL-10 in individuals infected by P. vivax. IFN-γ levels were higher in individuals who were infected for the first time, but there were no association with parasite elimination. Increased levels of IL-10 were associated with higher parasite densities. We did not detect IL-4 and IL-12 seric levels. The frequencies of AA, AT, TT genotypes of IFNG+874 were 0,51, 0,39 e 0,10, respectively. The frequencies of AA, AG, GG genotypes of IL10-1082 were 0,49, 0,43 e 0,08, respectively. We also showed that IFG+874 polymorphism is associated with decreased levels of IFN-γ. The results show a Th1-driven immune response which can be regulated by IL-10 in naturally P.vivax-infected individuals.