When only M. tuberculosis culture-positive TB cases were selected for analysis, retreatment TB patients were found to have higher frequencies of CD244/2B4-expressing antigen-responsive CD4+ T cells than latent infection individuals (p = 0.0098) and new TB patients (p = 0.0339) as well (Fig. 2E). This evidence concerns the gene CD4 and disease arising from reactivation of latent virus.