Circulation level of matrix metalloproteinase-9 is correlated with disease severity in tuberculosis patients.

SETTING

Parenchymal lung destruction accompanied by active tuberculosis is, at least in part, caused by host as well as bacillus metalloproteinases. Mycobacterium tuberculosis has been shown to stimulate MMP-9 expression in the lung of infected organisms.

DESIGN

We have used quantitative zymography and computer-assisted image analysis to measure the levels of type IV collagenases in 20 serum samples of patients with active tuberculosis and in 23 serum samples of healthy volunteers.

RESULTS

Mean levels of the serum MMP-9 were over three-fold higher in tuberculous samples compared with normal serum (P < 0.0001), whereas the MMP-2 levels did not differ in these two groups. The levels of MMP-9 were significantly higher in subjects with advanced disease than in those with only limited disease changes (P < 0.05).

CONCLUSIONS

We suppose that the elevation of serum MMP-9 levels in patients with tuberculosis is affected by the augmentation of synthesis and/or secretion of this enzyme by inflammatory cells in response to M. tuberculosis infection. The observed association between the serum MMP-9 level and the extent of radiological change suggests that the quantification of the serum level of this enzyme may constitute a supplementary test in pulmonary tuberculosis diagnostics.