Associação de polimorfismos dos genes TNFa e IL1ß com a toxoplasmose gestacional

Abstract

Toxoplasmosis is a zoonosis with wide geographical spread and high human prevalence. One of the main impacts of Toxoplasma gondii (T. gondii) infection occurs during pregnancy and it is associated with vertical transmission (congenital toxoplasmosis) that can cause severe clinical condition and fetal death. During acute infection, to control the rapid replication of tachyzoites, different host immune response genes are activated, among them, genes encoding cytokines. Cytokines are immune modulating molecules secreted mainly by macrophages and T cells and influence cell activation, differentiation and function. In reason of the high incidence of gestational toxoplasmosis in the Northwest of São Paulo state and considering that polymorphisms in cytokine genes may favor susceptibility to vertical transmission of T. gondii by determining the immunological status of the pregnant woman. Thus, the objective of this study was defined. Objective: To evaluate the influence of polymorphisms of genes TNFα (-1031 position) and IL1β (-511 position) on gestational toxoplasmosis. Materials and Methods: Pregnant patients, with (n = 114) or without (n = 90) T. gondii infection, attended at the specialty clinic ambulatory of Hospital de Base (FUNFARME) in São José do Rio Preto -SP participated in this study. Polymorphisms were identified by the Polymerase Chain Reaction-Restriction Fragment Polymorphism (PCR-RFLP) technique. Comparisons of allele and genotype frequencies between groups of patients were performed using the chi-square method (χ2) with Yates correction or Fisher's exact test. The genotypic frequencies were evaluated among themselves, using the dominant and recessive inheritance models. P≤ 0.05 values were considered statistically significant. Results: No influence relationships were found involving the polymorphisms rs1799964 (-1031) of the TNFα gene and rs16944 (-511) of the IL1β gene with gestational toxoplasmosis and vertical transmission of the parasite. However, the TNF α polymorphism seems to influence the clinical signs of children born in the group of pregnant women with acute toxoplasmosis (IgM+/IgG+) by T. gondii (P = 0.007; χ2 = 9.68). Conclusion: The results showed that the investigated polymorphisms do not seem to have an influence on gestational toxoplasmosis and vertical transmission of the parasite. However, the TNF α -1031 polymorphism seems to influence the clinical signs of children born from pregnant women with acute toxoplasmosis.