Neutrophil gelatinase-associated lipocalin (NGAL) is a 25 kD lipocalin that is covalently bound to matrix metalloproteinase (MMP)-9 produced by neutrophils [1]. NGAL in blood or bronchoalveolar lavage fluid (BALF) may reflect neutrophilic inflammation in the lungs [2, 3], and it is highly induced in injured epithelial cells, including those in the lung [4]. Possible roles for neutrophilic infla...