Association between TNF, IL1B, IL6, IL10 and IFNG polymorphisms and recurrent miscarriage: a case control study

BACKGROUND Approximately half of recurrent miscarriages have unexplained etiology. Recent evidences suggest that cytokines are important determinants in pregnancy maintenance and as such, cytokine gene polymorphisms, which can affect cytokine production and/or functionality, could play a role in the disorder. Thus, we aimed to investigate the association of selected cytokine gene polymorphisms with risk of recurrent miscarriage among Chinese. METHODS TNF -238G > A, TNF -308G > A, IL1B -511 T > C, IL1B 3954C > T, IL6 -174G > C, IL6 -634C > G, IL10 -1082A > G and IFNG 874A > T polymorphisms were genotyped on 775 women with idiopathic recurrent miscarriage and 805 healthy parous control women. Logistic regression analysis was performed to determine the odds ratios (ORs) of the association between the polymorphisms and recurrent miscarriage risk. RESULTS Among the eight polymorphisms studied, only the IL1B -511 T > C and IL6 -634C > G polymorphisms showed statistically significant associations with recurrent miscarriage risk. For the former, a significantly increased risk of recurrent miscarriage was observed for the mutant (CC) genotype (OR: 1.377; 95% CI: 1.039-1.824; P = 0.026). However, for the IL6 -634C > G polymorphism, a decreased recurrent miscarriage risk was observed for the heterozygous (CG) genotype (OR: 0.614; 95% CI: 0.493-0.765; P < 0.001) and the mutant (GG) genotype (OR: 0.414; 95% CI: 0.251-0.684; P = 0.001). CONCLUSIONS The IL1B -511 T > C polymorphism may serve as important risk factor for recurrent miscarriage while the IL6 -634C > G polymorphism may protect against the risk of recurrent miscarriage.