Association of C-reactive protein and Interleukin-6 single nucleotide polymorphisms with preterm labour: results of a pilot study

Preterm labour (PTL) can be described as an inflammatory event. C-reactive protein (CRP) and Interleukin-6 (IL-6) are key members of the innate immune response that play major roles in inflammation. The main objective of this case-control study was to determine the association of specific CRP and IL-6 polymorphisms with PTL. The study was carried out in a total of 31 Japanese women with PTL and 28 control women with normal pregnancy. Four SNPs in the CRP gene (rs1800947, rs3091244, rs2794521, and rs3093059) and two SNPs in the IL-6 gene (rs2097677 and rs1800795) were genotyped using a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay. Biochemical parameters were assayed and cervical length measurements were performed with ultrasound sonography. There were no significant differences in inflammatory markers, including white blood cell count, CRP, neutrophil elastase in cervical mucous, and foetal fibronectin in vaginal discharge, between the PTL and control groups. The frequency of rs1800947 minor allele (G) was significantly higher in the PTL group than in the control group. This finding has not been previously reported. We suggest that mutations in rs1800947 may lead to PTL. Thus, the rs1800947 SNP may be useful as a genetic marker for PTL risk assessment in pregnant women.