Multifunctional CD4(+) T cells correlate with active Mycobacterium tuberculosis infection.

Th1 CD4(+) T cells and their derived cytokines are crucial for protection against Mycobacterium tuberculosis. Using multiparametic flow cytometry, we have evaluated the distribution of seven distinct functional states (IFN-gamma/IL-2/TNF-alpha triple expressors, IFN-gamma/IL-2, IFN-gamma/TNF-alpha or TNF-alpha/IL-2 double expressors or IFN-gamma, IL-2 or TNF-alpha single expressors) of CD4(+) T cells in individuals with latent M. tuberculosis infection (LTBI) and active tuberculosis (TB). We found that triple expressors, while detectable in 85-90%TB patients, were only present in 10-15% of LTBI subjects. On the contrary, LTBI subjects had significantly higher (12- to 15-fold) proportions of…