Considering the endemicity of LTBI in India, where the estimates for adult prevalence range from 20 to 60% [3,5] and where TB is the single largest comorbidity associated with HIV infection, it is likely that a large proportion of HIV-associated TB might result from the reactivation of latent infections, although higher baseline CD4 counts (and CD4/CD8 ratios) are also known to reduce the risk of active TB infection [24,25]. This evidence concerns the gene CD4 and tuberculosis.