LIDOCAINE IN BRONCHOALVEOLAR LAVAGE FLUID (BALF) IS AN INHIBITOR OF EOSINOPHIL-ACTIVE CYTOKINES

Eosinophils and eosinophil granule proteins may play an important role in the pathogenesis of asthma. BALF from 40 patients with symptomatic asthma were analysed for cytokine activity by the eosinophil survival assay. BALF from 15 patients showed increased survival activity. Surv ival activities in BALF from four of these patients were almost comple tely blocked by anti-IL-5 MoAb, and the remaining activities were bloc ked by anti-granulocyte-macrophage colony-stimulating factor (GM-CSF), anti-IL-3 antibody, or both. Surprisingly, BALF samples from the othe r 25 patients decreased eosinophil viabilities below the levels of med ium control. The inhibitory factor in these BALF was of low molecular weight, was heat-stable, was largely overcome by excess exogenously ad ded cytokines, and was positively correlated with the concentrations o f lidocaine in the BALF. Lidocaine itself inhibited eosinophil surviva l at concentrations less than those present in the BALL. These finding s indicate that lidocaine is an inhibitor of cytokines in the eosinoph il survival assay, and they suggest the need for caution in analyses o f BALF containing lidocaine or other local anaesthetics.