Relationships Among Cytokines (IL-1, TNF, and IL-8) and Histologic Markers of Acute Ascending Intrauterine Infection

Abstract

Amniotic fluid levels of interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), and interleukin-8 (IL-8) were determined in 13 pregnancies presenting with preterm spontaneous membrane rupture in which there were no clinical indications of intraamniotic infection. These levels were compared to the placental histology. All 8 cases in which elevated cytokine levels were identified also had histologic evidence of both maternal and fetal acute inflammation in choriodecidua and chorionic plate, and umbilical and chorionic vessels, respectively. Cytokine concentrations correlated with the severity of maternal inflammation, but not the severity of fetal inflammation as assessed histologically. Elevated levels of both IL-1β and TNF-α were not uniformly observed in amniotic fluid; all cases with either elevated IL-1β of TNF-α had elevated levels of IL-8. Microbial studies of the 8 patients with histologic acute inflammation showed 5 with positive amniotic fluid cultures and/or gram stains. One had positive gram stain only for gram positive cocci, and the 4 remaining grew mixed vaginal flora (2), Fusobacterium spp. (1), and E. coli (1). One aspect of the functional immaturity of the fetal polymorphonuclear leukocyte may be related to impaired response to IL-8. In addition, the presence of IL-8 may be a clinical indicator of intraamniotic infection.

Key Words:

• Cytokines
• Intrauterine infection
• Amniotic fluid
• Preterm PROM
• Intraamniotic infection