Gender biased immune-biomarkers in active tuberculosis and correlation of their profiles to efficacy of therapy

Active pulmonary TB is an inflammatory disease and is increasingly viewed as an imbalance of immune responses to Mycobacterium tuberculosis (M. tb.) infection. In addition, this immune imbalance may be gender biased (males have a higher prevalence of TB) but reasons for such bias are uncertain. We hypothesized that studies on profiles of immune-biomarkers will not only provide insight into molecular basis of gender bias but may also help identify biomarkers to monitor efficacy of TB therapy. We examined 10 plasma cytokine/chemokine/growth-factor and 8 antibody (against 8 M. tb. antigens) biomarkers (elevated in TB patients) by multiplex microbead immunoassays. In addition, we examined these biomarkers in patients under anti-tuberculosis therapy (ATT). The results showed that female patients contained significantly higher levels of CXCL9 (MIG) and CXCL10 (IP-10), while males contained higher levels of PDGF-BB. In contrast, more males than females contained antibodies against several antigens. Our results also show that there are progressive and substantial decreases in plasma levels of CXCL9, CXCL10, PDGF-BB, IFNγ, and IL-18, correlating with treatment success. Our results suggest that studies on gender bias in immunebiomarkers will enhance understanding of host responses in TB and would be valuable as biomarkers for monitoring efficacy of ATT.