Tuberculosis infection elicits the production of MMP-9 by direct interaction between cell wall components of bacilli, human monocytes and macrophages.[6] The higher increase of MMP-9 in pleural effusions of tuberculous meningitis patients than in patients with malignant pleural disease also signifies the role of MMP-9 in tuberculous infections and vice versa [7]. This evidence concerns the gene MMP9 and Pleural effusion.