When should antiretroviral therapy be started in HIV-positive persons?

Recommendations for the initiation of combination antiretroviral therapy in HIV-positive individuals are largely based on data from observational studies. Whilst all guidelines recommend immediate treatment in individuals with a CD4 count of less than 350 cells/mm(3), guidelines vary in their recommendations for treatment at higher CD4 counts. Several large cohort studies have published findings that contribute to the debate, although conclusions vary and results from these studies may be subject to bias.