Interleukin-18 and interleukin-12 in maternal serum and spontaneous preterm delivery

Abstract Introduction Mice disrupted for the interleukin (IL)-18 gene appear more disposed to preterm delivery (PTD) induced by inflammation. A synergy between IL-18 and IL-12 has been suggested. The objective of this study was to investigate a possible relation between human maternal serum levels of IL-18, IL-12 and spontaneous PTD. Materials and methods A cohort of 93 consecutive women with symptoms of threatening PTD on admission was enrolled at the delivery ward, Aarhus University Hospital, Denmark. Measures : Serum IL-18 and IL-12 measured using Luminex xMAP technology. Endpoint : PTD before 34 weeks gestation. Results Pregnant women admitted with symptoms of threatening PTD and delivering before 34 weeks of gestation had significantly lower levels of IL-18 compared to women delivering at or after 34 weeks of gestation (medians: 14.5 versus 26.6 pg/ml; p = 0.035). IL-12 levels were not different in women delivering before or after 34 weeks of gestation. Patients having low IL-18 (below the 25-percentile) and high IL-12 (above the 75-percentile) had a twofold increase in risk of delivering before 34 weeks of gestation (RR 2.1 [1.7–2.6]). Conclusion Results from this study indicate, that low serum IL-18 level could be associated with PTD in women with symptoms of PTD. A possible interaction between IL-18 and IL-12 was found, as the risk of delivering before 34 weeks is increased with the combination of low IL-18 and high IL-12, but further studies are warranted to investigate these interleukins and their possible role in PTD.