Effect of matrix metalloproteinase-9 -1562C/T gene polymorphism on manifestations of pulmonary tuberculosis

Increased levels of matrix metalloproteinase-9 (MMP-9) in patients with tuberculous meningitis, tuberculous pleuritis, and advanced pulmonary tuberculosis (TB) suggest a pivotal role for MMP-9 in the development of pulmonary TB and its clinical manifestations. The present study was performed to evaluate the role of the -1562C/T single nucleotide polymorphism (SNP) in the promoter region of the human MMP-9 gene in development of pulmonary TB and its radiographic characteristics. A case-control study was performed with a study population of 205 patients with pulmonary TB and 223 healthy controls. Differences were explored in the allele and genotype distributions of the -1562C/T polymorphism between patients with pulmonary TB and healthy controls, between patients with single- and multi-lobe involvement, and between patients with and without cavities. The -1562C/C genotype was more common in patients with multi-lobe involvement than in those with single-lobe involvement (81.8 vs. 67.6%, P = 0.03). However, there were no significant differences in the distribution between patients with pulmonary TB and healthy controls (P = 0.40) or between patients with and without cavities (P = 0.18). These results suggest that the -1562C/C genotype is associated with the intrapulmonary spread of TB rather than its development.