Association of tuberculosis and polymorphisms in the promoter region of macrophage migration inhibitory factor (MIF) in a Southwestern China Han population

► We investigated the association between two MIF promoter polymorphisms and tuberculosis. ► The 173 (GC+CC) SNP and -794 (7/X+8/X) microsatellite increased the risk of TB. ► The MIF promoter polymorphisms distributions are dependent on race , environmental and genetic factors. The macrophage migration inhibitory factor (MIF) is a pro-inflammatory cytokine that plays an important role in the pathogenesis of immune diseases. High levels of MIF have been detected in the sera of patients with tuberculosis (TB), and it has been proposed that MIF gene polymorphisms may influence the risk of developing TB. The aim of this study was to evaluate the potential relationship between functional polymorphisms of MIF and TB in a Han population from Southwestern China. TB patients (n=215) and healthy unrelated controls (n=245) were recruited for this study. Genomic DNA was isolated from all the participants. The MIF-173 G/C SNP was genotyped using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). The MIF-794 CATT5–8 microsatellite was evaluated by direct sequencing of the subsequent PCR products. Association analysis of the two polymorphisms showed that the frequency of -173 (GC+CC) in TB patients and controls was 49.3% and 31.4%, respectively, which was statistically significant (OR=2.12, 95% CI=1.45–3.10, P