Among the 11 subjects with active TB classified as “mitogen-unresponsive”, only 18.2% (2/11) responded to the assays based on IFN-γ in response to RD1 selected peptides compared to 58.8% (10/17) of the “mitogen-responsive”, and this difference was significant (p = 0.02). This evidence concerns the gene PDE6B and tuberculosis.