Avaliação genética e funcional de FOXP3, IL17A e dosagem de citocinas pró e anti-inflamatórias em mulheres com pré-eclâmpsia

Abstract

Preeclampsia (PE) is a multisystemic disease specific of pregnancy, which is important for maternal and neonatal morbidity and mortality. Recent findings suggest that significant changes in the immune system are involved in PE pathogenesis. It has been proposed that the reduction of regulatory T cells (Tregs) with consequent failure in immunological tolerance promotes the increase of pro-inflammatory cytokines, generating endothelial dysfunction and oxidative stress. FOXP3 is a critical transcription factor to induce differentiation of Tregs, besides polymorphisms located in the promoter region of this gene can alter the production and function of Tregs cells. IL17A is the major cytokine secreted by Th17 cells and in excess induces tissue inflammation. Polymorphisms in FOXP3 gene have already been associated with the pathogenesis of many autoimmune and inflammatory diseases. Therefore, we investigated rs3761549C> T, rs3761548A> C and rs2232365A> G polymorphisms in FOXP3 gene and rs4711998 A> G, rs8193036 C>T and rs2275913 A>G polymorphisms in IL17A gene. We also quantified these genes and IL12, TNF-α, IL10, IL6 and IL8 levels in PE. Genotyping was performed by Real Time PCR. The relative expression of the FOXP3 and IL17A genes was performed by qPCR in 17 placental samples from the PE group and 14 from the Control group. Cytokine quantification was performed by flow cytometry. Continuous variables were described by mean ± standard deviation and categorical variables were expressed by percentage. Comparisons between both groups were performed using an unpaired Student’s t test, Mann– Whitney U test or Chi square (χ2) test as appropriate. The genetic models and haplotypes were analyzed by SNPStat software. Significance was assumed when the statistical tests returned Pvalues <0.05. A total of 263 women, study group (PE = 89) and control group (C = 174) participated in the study. There was no association between the genotypic and allelic frequencies, as well as the inheritance models for the polymorphisms investigated and the PE. The control group of polymorphisms rs3761548 in the FOXP3 gene and rs4711998 of the IL17A gene were not in Hardy-Weinberg equilibrium. There was no association between haplotypes and PE. Primiparity and familial recurrence were associated with PE risk. The expression of FOXP3 was statistically higher in the PE group. Statistically elevated levels of IL8 and IL6 were observed in women with late-onset PE. Therefore, there is no association between rs3761549C>T, rs3761548A>C and rs2232365A> G in the FOXP3 gene and rs4711998 A>G; rs8193036 A>T and rs2275913 A>G polymorphisms in the IL17A gene and PE. Familial recurrence and16 primiparity are considered risk factors for PE in the sample studied. Elevated levels of FOXP3 are associated with the development of early-onset PE. High levels of IL6 and IL8 are associated with late-onset PE.