Interleukin-1beta-511T>C genetic variant contributes to recurrent pregnancy loss risk and peripheral natural killer cell proportion

Objective: To identify whether interleukin gene polymorphisms are risk factors for idiopathic recurrent pregnancy loss (RPL) in Korean women. Design: Case-control study. Setting: Hospital-based study. Patient(s): A cohort of 385 idiopathic RPL patients and 232 controls with Korean ethnicity. Intervention(s): None. Main Outcome Measure(s): Genotyping was assessed with a polymerase chain reaction-restriction fragment length polymorphism assay. We examined polymorphisms in three interleukin (IL) genes: IL-1 beta, IL-4, and IL-10. Result(s): The IL-1 beta-511T>C polymorphism was associated with RPL (-511TT vs. -511CC: adjusted odds ratio 1.826; 95% confidence interval 1.130-2.953). Allelic gene-gene interaction analysis revealed that the T/B2/G (IL-1 beta/IL-4/IL-10) allele combination was only detected in the RPL group (adjusted odds ratio 20.046; 95% confidence interval 1.188-338.204). The proportion of peripheral natural killer cells was higher in patients with the IL-1 beta-511C allele compared with the -511T allele. Conclusion(s): According to these results, IL-1 beta-511T>C may be a predisposing factor to RPL susceptibility. However, the mechanism underlying the function of IL-1 beta-511T>C in RPL remains to be determined, and further studies are needed to improve understanding of the roles of IL-1 beta-511T>C, using a larger and more heterogeneous cohort. (C) 2014 by American Society for Reproductive Medicine.