Serum levels of interleukin-6, interleukin-1β and human chorionic gonadotropin in pre-eclamptic and normal pregnancy

Abstract

Studies in placentas from the first trimester and in vitro models indicate that interleukin (IL)-1beta and IL-6 induce the release of human chorionic gonadotropin (hCG). During pre-eclampsia there is an increase of pro-inflammatory cytokines; however, its relationship with hCG levels during the third trimester of pregnancy has not been determined. The aim of the present study was to evaluate the relationship between blood levels of IL-6, IL-1beta and hCG in normal pregnancy and pre-eclampsia. Blood samples during the third trimester of pregnancy from women with severe pre-eclampsia (n = 20) or normal pregnancy (n = 20) were assayed for hCG by immunoassay, IL-6 and IL-1beta by enzyme-linked immunosorbent assay. Serum level of IL-6 was significantly higher in pre-eclamptic than in normal women (16.5 +/- 2.1 vs. 4.9 +/- 1.1 pg/ml); however, IL-1beta was similar in both groups. Although hCG was higher in pre-eclampsia than normal pregnancy, the difference was not statistically significant. Furthermore, IL-1beta in normal pregnancy was correlated negatively with hCG (r = -0.69, p < 0.001). In conclusion, serum levels of IL-6 were increased in pre-eclampsia but were not correlated with hCG or IL-1beta; however, in normal pregnancy there was a negative correlation between IL-1beta and hCG. The interaction between IL-1beta and hCG at the third trimester needs to be investigated.