Elevated levels of myeloperoxidase, pro-inflammatory cytokines and chemokines in naturally acquired upper respiratory tract infections

Upper respiratory tract infections (URTIs) are characterised by a neutrophi lic mucosal infiltration. The purpose of this study was to investigate the time course of release of the cytokines/chemokines interleukins (IL) IL-1 b eta, IL-1r alpha, tumour necrosis factor-alpha (TNF-alpha), IL-6, IL-8, int erferon-gamma (IFN-gamma) and monocyte chemotactic protein (MCP-1), soluble intercellular adhesion molecule-1 (sICAM-1), myeloperoxidase (MPO) and bra dykinin in nasal secretions of patients with a naturally acquired URTI. A t otal of 117 healthy adult volunteers were recruited for baseline nasal lava ges, 39 of whom developed URTI symptoms within 6 months and returned to our centre within 48 h. Lavages were performed daily during the symptomatic pe riod and 3 weeks thereafter, with symptoms no longer present. Compared to b aseline, significantly elevated concentrations of total protein, bradykinin , IL-1 beta, TNF-alpha, IL-6, IL-8, MCP-1, IFN-gamma, MPO and sICAM-1 were detected in nasal lavage fluids of symptomatic patients, whereas IL-1ra rem ained unaltered. All studied variables reached baseline 3 weeks after the U RTI. Naturally acquired URTI represent a limited, neutrophilic inflammatory reaction, orchestrated by the release of pro-inflammatory cytokines and ch emokines.