Neutrophil Elastase and Its Complex with α1-antitrypsin in Soluble and Insoluble Fractions of Nasal Secretions of Chronic Sinusitis

Immunoreactive neutrophil elastase (NE) and its complex with alpha 1-antitrypsin (AT) was measured by double antibody enzyme linked immunosorbent assay (ELISA) in nasal secretions of chronic sinusitis (CS). Nasal secretions were separated into two fractions: PBS-soluble and insoluble fractions. Elastolytic activity was also examined. Mean value of total NE level was 31.0 micrograms/ml in the soluble fraction, which was significantly lower than that in the insoluble fraction (71.9 micrograms/ml, p less than 0.01). On the other hand, the percentage of complexed NE in total NE in the soluble fraction (33.7%) was significantly higher than that in the insoluble fraction (12.1%, p less than 0.01). Elastolytic activity in the soluble fraction (23.4 RFU) was significantly lower than that in the insoluble fraction (170.5 RFU, p less than 0.01). NE with elastolytic activity exists in nasal secretions of CS, and active-free NE in the insoluble fraction could be a major source of enhancement and continuation of mucosal inflammation.