['Nitric Oxide (NO) is reported to possess anti-inflammatory properties. The aim of this study was to investigate if nitric oxide affects leukocyte response during simulated extracorporeal circulation (SECC).', 'Human blood was circulated for 23 hours through SECC circuit. Control group C (n = 5) was ventilated with an oxygen/air mixture, and NO was added in the study group (n = 5). Leukocyte response was determined by release of myeloperoxidase (MPO) and human neutrophil lipocalin (HNL) and by oxygen free radical production, estimated using chemiluminescence.', 'Addition of NO significantly increased MPO at 30 minutes and 120 minutes of SECC and HNL at 120 minutes of SECC. Oxygen free radical production in whole blood was generally not affected by NO. Similarly, no significant differences were observed between the groups with regard to the chemiluminescence in isolated granulocytes.'] Does nitric oxide increase leukocyte granule release during simulated extracorporeal circulation?