Plasma Levels of sFas-sFasL and FASL Gene Expression Are Associated with Tuberculosis

Apoptosis of macrophages infected by Mycobacterium tuberculosis via Fas-FasL is an important immune mechanism against infection. This study investigated the association of tuberculosis (TB) with the presence of the polymorphisms FAS -670A/G and FASL -124A/G, the levels of sFas and sFasL, and the gene expression of FASL and cytokines. Samples of 200 individuals diagnosed with TB and 200 healthy controls were evaluated. Real-time PCR (genotyping and gene expression) and ELISA (dosages of sFas, sFasL, IFN-gamma, and IL-10) tests were performed. There was no association of FAS -670A/G and FASL -124A/G polymorphisms with TB. The TB group exhibited high plasma levels of sFas and reduced plasma levels of sFasL (p < 0.05). The correlation analysis between these markers revealed a positive correlation between the levels of sFas and sFasL, sFasL and FASL expression, and between sFas and FASL expression (p < 0.05). In the TB group, there was a positive correlation between FASL expression and IFN-gamma levels and higher levels of IL-10 compared to IFN-gamma (p < 0.05). High levels of sFas and reduced levels of sFasL and FASL expression may contribute to the inhibition of apoptosis in infected cells and represent a possible bacterial resistance resource to maintain the infection.

Automated summary

Apoptosis of macrophages infected by Mycobacterium tuberculosis via Fas-FasL is an important immune mechanism against infection. This study investigated the association between tuberculosis and FAS -670A/G and FASL -124A/G polymorphisms, as well as the levels of sFas and sFasL, and gene expression of FASL and cytokines. The results showed no association between the polymorphisms and tuberculosis. However, the tuberculosis group had higher levels of sFas and lower levels of sFasL. The study also found positive correlations between sFas and sFasL levels, sFasL and FASL expression, and between sFas and FASL expression.