Decline in FEV1 in Community-Based Older Volunteers with Higher Levels of Neutrophil Elastase in Bronchoalveolar Lavage Fluid

Background: Neutrophil elastase (NE) is thought to be one of the key proteinases in the development of chronic obstructive pulmonary disease (COPD). Previously, we have shown that the NE-α1-proteinase inhibitor (NE-α1PI) complex in bronchoalveolar lavage (BAL) fluid was markedly elevated in asymptomatic smokers who had subclinical emphysema on CT scans. We proposed that excessive NE-α1PI complex in BAL fluid was a factor which might differentiate smokers who were developing emphysema from others. Objective: In this study, we addressed the question of whether elevated levels of the NE-α1PI complex in BAL fluid are linked to the accelerated decline in pulmonary functions in those subjects. Methods: We conducted a follow-up study to analyze the decline in FEV1 for 4.3 years on average for 26 community-based volunteers who had received pulmonary function tests, CT scans and BAL. The levels of the NE-α1PI complex in BAL fluid and in plasma was measured. Results: Neither pulmonary function measurements nor the presence of emphysema on CT scans could predict the decline in FEV1. The number of inflammatory cells in BAL fluid was also not an indicator of progression. By contrast, subjects with higher levels of the NE-α1PI complex in BAL fluid had a significantly accelerated decline in FEV1 compared to those with lower levels. Conclusion: These data seem to support the hypothesis that NE in the lung is related to the onset and/or progression of COPD.