The effects of antiinflammatory and antiallergic drugs on cytokine release after stimulation of human whole blood by lipopolysaccharide and zymosan A.

IL-1 beta, IL-8, IL-6 and TNF alpha, derived from infiltrating leukocytes, are important mediators of inflammation in arthritic and allergic diseases. Heparinized human whole blood was evaluated as a model to study the effects of various classes of antiinflammatory drugs on cytokine release/biosynthesis from leukocytes. Whole blood was stimulated with zymosan A (1.5 mg/ml) or LPS (5 micrograms/ml) for 4 h to induce cytokine release. Dexamethasone was the most potent inhibitor of TNF alpha, IL-1 beta, IL-6 and IL-8 release from LPS stimulated blood leukocytes (IC50s of 0.19, 0.11 microM, 0.16 and 0.07 respectively). In LPS stimulated blood, SKF-86002, a 5-lipoxygenase/cytooxygenasae inhibitor, and rolipram, a PDE IV inhibitor, also inhibited the release of TNF alpha (IC50s of 33 and 11 microM, respectively), IL-1 beta (IC50s of 11 and 30 microM, respectively), IL-6 (IC50s of 56 and > 30, respectively) and IL-8 (IC50s of 6.7 and 15, respectively), whereas isoproterenol (1 microM) inhibited significantly only TNF alpha release. Nonsteroidal antiinflammatory drugs, 5-lipoxygenase inhibitors and immuno-suppressive drugs were inactive at 30 microM against LPS and zymosan A stimulation of cytokine release. Using zymosan A as the stimulus, only SKF-86002 (30 microM) showed significant inhibition of IL-1 beta (-59%). This 4 h human blood assay has the potential to identify novel inhibitors and sites of actions (e.g. transcription, post-transcriptional and secretion) of new antiinflammatory drugs.