CD4 and tuberculosis: Although there were some early indications that those with TB disease are more infectious [59]–[61], the largest study conducted among HIV-positive people with incident TB disease indicated that viral load increases by only a small amount following a TB episode [62], and a more recent study showed that treating active TB disease in individuals with CD4 counts greater than 350 cells/μl reduced markers of immune activation but had no effect on HIV viral load or CD4 count [63].