Erythrocyte-bound interleukin-8 and RANTES in human endotoxemia.

Erythrocytes have been suggested to bind chemokines, thus limiting their effective concentration in the circulation. We investigated binding of the chemokines IL-8 and RANTES to erythrocytes following endotoxin challenge. Endotoxin caused a transient increase of IL-8 in plasma, and a gradual increase of erythrocyte-bound IL-8, remaining elevated for at least 24 h in vivo. Binding of IL-8 to erythrocytes was confirmed by incubation of freshly isolated erythrocytes with endotoxin stimulated plasma. Incubation for 1 h led to a decrease in plasma concentrations of IL-8 with a concomitant increase in erythrocyte-bound IL-8 levels. Erythrocyte-bound RANTES was induced early following endotoxin infusion and our data may suggest competition between the two chemokines for the same binding site on erythrocytes in vivo. In conclusion, in humans, both IL-8 and RANTES are induced by endotoxin and are, at least in part, cleared from the plasma by binding to erythrocytes. [ABSTRACT FROM PUBLISHER]