Potential agonist action of the interleukin-1 receptor antagonist protein: implications for treatment of women.

The interleukin-1 receptor antagonist protein (IRAP) caused a concentration-related increase in prostaglandin production by human decidual cells. The degree and time course of this stimulatory action were identical to those induced by interleukin 1 beta (IL-1 beta). IRAP had no inhibitory action on IL-1 beta stimulation of decidual prostaglandin production and at high concentrations had an additive effect. We believe that this represents the first description of a potential agonist action of IRAP and suggests caution in treatment of women with this substance.