Investigating the Association of IL-17A and IL-17F with Susceptibility to Pre-eclampsia in Iranian Women

Background: Pre-eclampsia (PE) is one of the most important and life-threatening pregnancy disorders that affect at least 3-5% of all pregnancies. Imbalance in helper T cell functions may play a role in predisposing to PE or severity of the disease. Elevated frequencies of Th17 cells in the peripheral blood of PE patients have been reported. Several single nucleotide polymorphisms (SNP) within IL-17 gene have been identified that may affect the IL-17 production. Objectives: To investigate the association between IL-17A (-197A/G) and IL-17F (+7488T/C) gene polymorphisms and susceptibility to PE in a group of Iranian women. Moreover, to study any correlation of the polymorphisms data with the level of IL-17, at mRNA level in the paternal and maternal parts of the placentas and also at protein level in the peripheral and placental blood samples. Methods: A group of 261 PE patients and 278 age-matched healthy women with at least two previous normal pregnancies formed the cases and controls of this study. IL-17A (-197A/G) and IL-17F (+7488T/C) polymorphisms were genotyped using PCR-RFLP method. The protein level of IL-17A was assessed in the sera of 40 PE and 40 healthy women using ELISA method and mRNA expression was also measured in placental samples of 19 PE and 19 control women using Q-PCR technique. Results: Statistical analysis indicated that there were no differences in genotype, allele or haplotype frequencies regarding the studied SNPs between cases and controls. The level of IL-17A was elevated in the placental blood and the fetal tissue at protein and mRNA levels (p< 0.009 and p<0.000, respectively) in PE as compared with the healthy women. Conclusions: The effect of IL-17 cytokine in pre-eclampsia is not due to the studied cytokine polymorphisms but local production of IL-17 might have an effect on the predisposition to the disease.