Matrix metalloproteinase-1 polymorphism in Taiwanese patients with endobronchial tuberculosis

Endobronchial tuberculosis (TB) often leads to some degree of tracheobronchial stenosis. Because matrix metalloproteinases (MMPs) play an essential role in tissue remodeling in the airways, we investigated the role of MMP-1 polymorphism in patients with endobronchial TB. One hundred and one cases of pulmonary TB in Taiwanese patients were genotyped for the 1G/2G polymorphism of MMP-1 promoter (-1607 bp). Bronchoscopic examination was performed to determine the presence of endobronchial involvement. Levels of MMP-1 in peripheral blood monocytes and in bronchial biopsies were also determined. 1G genotypes of MMP-1 polymorphism, containing at least one 1G allele, were associated with the presence of endobronchial TB. Using multivariate analysis, 1G genotypes and female gender were independent predictors of the development of endobronchial TB. Endobronchial TB patients with 1G genotypes had a 9.86-fold greater risk of developing tracheobronchial stenosis. IL-1beta increased levels of MMP-1 in peripheral blood monocytes of TB patients with 1G genotypes. MMP-1 activity was also present in the endobronchial TB granuloma from patients with 1G/1G genotype. 1G genotypes of MMP-1 polymorphism were associated with a greater risk of developing tracheobronchial stenosis through up-regulation of MMP-1 activity.