A polymorphism of the interleukin-1β gene and idiopathic recurrent miscarriage

Objective: Proinflammatory cytokines have been described to be involved in the pathogenesis of idiopathic recurrent miscarriage (IRM). We investigated the association between IRM and a polymorphism in exon 5 of the interleukin-1 beta gene (IL1B) and interleukin-1 beta (IL-1 beta) serum levels. Design: Case control study. Setting: Academic research institution. Subjects: One hundred thirty-one women with a history of three or more consecutive pregnancy losses before 20 weeks' gestation and 68 healthy controls with at least two live births and no history of pregnancy loss. Interventions: Peripheral venous puncture. Main Outcome Measures: An IL1B exon 5 (position +3953) gene polymorphism was analyzed by PCR amplification followed by restriction fragment length polymorphism analysis. IL-1 beta serum levels were analyzed by a commercially available ELISA. Results: Allele frequencies in women with IRM and controls were 77.9% and 80.8%, respectively, for the E1 allele (wild type), and 22.1% and 19.2%, respectively, for the E2 allele (mutant). No association between the E2 allele and the occurrence of IRM was found (P=.57, odds ratio =.83). Genotype frequencies and IL-1 beta serum levels were not significantly different between the study group and the control group. Conclusions: This is the first report on an IL1B polymorphism in IRM. Although known to alter IL-1 beta expression, the investigated IL1B polymorphism is not associated with IRM and increased serum levels in a large Caucasian population. (C) 2001 by American Society for Reproductive Medicine.