Recent papers showed a multidimensional analysis of the activation state of TB-specific CD4+ T-cells reactive to the TB antigens PPD or ESAT-6/CFP-10 by expression of CD154, CD38, HLA-DR, and Ki-67 where they observed higher frequency of activated cells in TB disease compared to TB infection(41–43) The decline in these activation markers with treatment reflects a resolution of the immune activation associated with active infection. This evidence concerns the gene CD4 and infection.