THE INTERLEUKIN-1 RECEPTOR ANTAGONIST IS A PARTIAL AGONIST OF PROSTAGLANDIN SYNTHESIS BY HUMAN DECIDUAL CELLS

In many systems the interleukin-1 receptor antagonist opposes the effects of interleukin-1 beta. We considered that it might block interleukin-1 beta-stimulated prostaglandin production from human decidual cells. Very high levels of interleukin-1 receptor antagonist (>1000 pg/ml) had limited inhibitory effects on IL-1 beta-stimulated PGE2 synthesis, and lower levels of antagonist (<1000 pg/ml) increased the effects of IL-1 beta. Low concentrations of the antagonist alone (1-100pg/ml) increased basal PGE2 production, whereas higher levels (10-100 ng/ml) had less effect. It seems, therefore, that in human decidua the ''antagonist'' is more accurately described as a partial agonist. It has been suggested that the IL-1 receptor antagonist could be used to inhibit decidual prostaglandin synthesis and thereby prevent preterm labor, but this report shows that caution should be exercised before using the receptor antagonist.