A METHOD FOR THE DETECTION OF ERYTHROCYTE-BOUND INTERLEUKIN-8 IN HUMANS DURING INTERLEUKIN-1 IMMUNOTHERAPY

Interleukin-8 (IL-8) has been recently shown to bind to human erythroc ytes with high affinity and is therefore potentially difficult to dete ct in serum or plasma. IL-8 is transiently elevated in the serum of ba boons after the administration of interleukin-1alpha (IL-1alpha). The objective of this study was to investigate whether IL-8 can be detecte d in the plasma or in detergent-lysed erythrocytes from cancer patient s undergoing treatment with IL-1alpha. Using a specific radioimmunoass ay (RIA), plasma IL-8 was detected within 1-2 h after the first IL-1al pha infusion. Thereafter, the levels declined rapidly and after 4-8 h were undetectable. Erythrocyte-bound IL-8 was detectable 1-2 h after t he increase in plasma levels. The erythrocyte-bound IL-8 levels were h igher than those measured in plasma and remained elevated long after t he plasma levels had become undetectable. Erythrocyte membranes accoun ted for all of the erythrocyte-associated IL-8, as IL-8 was undetectab le in the cytosol after erythrocyte lysis. The assay used in these stu dies detects IL-8 in erythrocyte lysates when it cannot be measured in plasma and may therefore be useful in monitoring IL-8 production in v ivo.