Resumen

Introduction: Expression of Suppressor of cytokine signaling (SOCS)-1 molecules is increased in patients with tuberculosis (TB). Early Secreted Antigen Target (ESAT)-6 kDa – induced IFN-γ responses indicate Mycobacterium tuberculosis infection. The effect of ESAT6- stimulation on SOCS1 in the host is not known. Methodology: Healthy asymptomatic controls had a negative (n = 16) or a positive ( n = 13) tuberculin skin test (TST). ESAT6-induced IFN- γ responses classified these controls as positive (EC ESAT6 IFN-γ (+), n = 5) or negative (EC ESAT6 IFN-γ (-), n = 24) responders. Patients had pulmonary (n = 21) or extra-pulmonary (n = 30) tuberculosis. Peripheral blood cells were stimulated with ESAT6 and mRNA expression of IFN- γ and SOCS1 was determined. Results: ESAT6-induced IFN-γ expression was raised in EC ESAT6 IFN-γ (+) as compared with EC ESAT6 IFN-γ (-), p = 0.019. ESAT6-induced SOCS1 mRNA expression was increased in both pulmonary TB and extra-pulmonary TB patients as compared with both EC groups. ESAT6-induced IFN-γ/SOCS1 mRNA expression ratio was decreased in TB patients as compared with both EC groups. Conclusion: The M. tuberculosis infection induces increased ESAT6-induced IFN- γ responses in both latent and active TB. Our data shows down-regulation of IFN- γ/SOCS1 expression to be induced only in active TB cases, distinguishing them from healthy individuals likely to have latent TB. A decreasing IFN- γ/SOCS1 ratio may leads to reduced Th1 immunity which contributes to inability of the host to control clinical disease.

Palabras clave: ESAT6; SOCS1; tuberculosis; IFN-γ; pulmonary TB; extra-pulmonary TB.

2014-01-15   |   558 visitas   |   Evalua este artículo 0 valoraciones

Vol. 8 Núm.1. Enero 2014 Pags. 59-66 J Infect Developing Countries 2014; 8(1)