Considering also the fact that increased T-cell apoptosis/anergy in TB patients is associated with pronounced changes in the functional activity of monocytes and generated in vitro DCs [21], we have suggested that T-cell dysfunction in tuberculosis infection could be also conditioned by enhanced DC cytotoxic activity mediated through PD-1/PD-L1 (B7-H1) signaling pathway. This evidence concerns the gene PDCD1 and tuberculosis.