To compare concentrations of interleukin-5 (IL-5), immunoglobulin E (IgE), eosinophilic cationic protein (ECP), and soluble intercellular adhesion molecule-1 (sICAM-1) in nasal secretion and serum of patients with chronic nonallergic sinusitis, allergic rhinitis, and nonallergic nasal polyposis to obtain information about the pathogenesis of these diseases.