Human placental cells show enhanced production of interleukin (IL)-8 in response to lipopolysaccharide (LPS), IL-1 and tumour necrosis factor (TNF)-α, but not to IL-6

Interleukin-8 (IL-8) is a chemotactic and activating factor for neutrophils which play important roles in host defence mechanisms. The human placenta constitutively produces IL-8 during pregnancy and enhances its production in chorioamnionitis. The present study was designed to investigate in vitro the regulatory mechanism for IL-8 production in the placentas in normal and inflammatory states. Placental cells produced IL-8 in a dose-dependent fashion when stimulated with lipopolysaccharide (LPS). The purified trophoblasts showed significantly higher IL-8 production than untreated placental cells. The expression of IL-8 gene in the trophoblasts in the third trimester was observed by reverse transcription‐polymerase chain reaction (RT‐PCR). The placental cells also release IL-8 in a dose-dependent manner, in response to r-(recombinant) IL-1a and tumour necrosis factor (TNF)-a, but not rIL-6. Moreover, LPS-activated placental cells spontaneously produced a much larger amount of IL-8 and showed increased responses to rIL-1a and TNF-a. It may, therefore, be proposed that placental cells with multiple endocrine functions exert immunological functions by constitutive production of IL-1 and TNF-a, which stimulate placental IL-8 release. This cytokine cascade in the placenta may be augmented by LPS in chorioamnionitis, thereby potentiating the feto‐maternal defence mechanisms against infection.