FETAL BUT NOT MATERNAL SERUM CYTOKINE LEVELS CORRELATE WITH HISTOLOGIC ACUTE PLACENTAL INFLAMMATION

Our objective was to determine if placental histologic acute inflammat ion is related to maternal and fetal serum cytokine levels in preterm labor, using a data set previously constructed blinded to histopatholo gic information. To this goal in 1992, 32 consecutive patients at 20-3 6 weeks with progressive labor and tocolytic failure were recruited. M aternal serum sampled during the active phase of labor, and fetal (umb ilical vein) serum were assayed by ELISA for levels of soluble interle ukin-1 beta (IL-1 beta), soluble interleukin-2 receptor (IL-2 R), and interleukin 6 (IL-6) (T-Cell Diagnostics). Acute placental inflammatio n was scored by two groups blinded to clinical data, and the average s cores analyzed for relationships to serum cytokine levels. Weighted ka ppa values, reflecting interobserver agreement in scoring of acute inf lammation, were: amnion 0.84; choriodecidua 0.84; umbilical cord 0.85; and chorionic plate 0.73. Fetal levels of IL-I beta and IL-2 R were h igher with grade 3-4 acute amnionitis than with grades 0-2 (p = 0.022 and p = 0.023). Fetal levels of all three cytokines were higher in gra de 3-4 umbilical vasculitis (IL-1 beta p = 0.008, IL-2 R p = 0.01, and IL-6 p 0.03). In contrast, maternal serum cytokine levels were not as sociated with presence or severity of histologic evidence of acute pla cental inflammation. Histologic acute inflammation was not related to duration of labor, interval from membrane rupture to delivery, and pre sence or duration of antibiotic therapy. We conclude that fetal serum, but not maternal serum cytokine levels, are correlated with histologi c evidence of acute placental inflammation, and may reflect a predomin ant placental origin of the cytokines.