The 2013 World Health Organization's (WHO) Consolidated guidelines on the use of antiretroviral drugs for treating and preventing HIV infection stipulate that ART initiation is recommended in all individuals with a CD4+ cell count of 500 cells/μL or less (but giving priority to those with advanced clinical disease or a CD4+ cell count less than 350 cells/μL); and at any CD4+ cell count in those with active TB, Hepatitis B infection and severe chronic liver disease, in HIV-positive partners in serodiscordant couples, and in pregnant and breastfeeding women. Here, CD4 is linked to HIV infectious disease.