Serum Macrophage Migration Inhibitory Factor as a Biomarker of Active Pulmonary Tuberculosis.

Background: Macrophage migration inhibitory factor (MIF), a pro-inflammatory cytokine with chemokine-like functions, has been shown to play a central role in several acute and chronic inflammatory diseases. However, limited information is available regarding the use of MIF as an inflammatory pathway marker in patients with tuberculosis. This study aimed to investigate the association of MIF with IFN-gamma and TNF-alpha in active pulmonary tuberculosis (APTB) following anti-tuberculosis treatment. Methods: The MIF, TNF-alpha, and IFN-gamma serum levels were determined in 47 patients with APTB by cytokine-specific ELISA at four phases: prior to anti-tuberculosis drug treatment (baseline), and following 2, 4, and 6 months of treatment. In addition, we measured the MIF, TNF-a, and IFN-gamma serum levels in 50 health controls. Results: MIF serum levels were significantly elevated (P < 0.05) in patients with APTB prior to treatment compared with that in control subjects, and TNF-alpha >= 449.7 pg/mL was associated with high MIF levels (>= 13.1 ng/mL). MIF levels were significantly reduced (P < 0.01) following 2, 4, and 6 months of treatment, with variations in TNF-alpha and IFN-gamma serum levels. MIF levels were positively correlated with the paired TNF-alpha level at baseline (r = 0.1103, P = 0.0316) and following 6 months of treatment (r = 0.09569, P = 0.0364). Conclusions: A reduction in the MIF serum levels in patients with APTB following anti-tuberculosis treatment may positively affect host immune protection against Mycobacterium tuberculosis infection. Thus, serum MIF levels may constitute a useful marker for assessing therapy effectiveness in patients with APTB.