Suppression of HIV replication using antiretroviral therapy allows the immune system to recover by producing new CD4 T-cells to replace those that have been killed by the virus. Typically, viral load suppression and CD4 cell recovery occur together after starting anti-HIV treatment. But sometimes patients experience an isolated virological or immunological response. This is discussed in Discordant viral load and CD4 cell responses.

Along with antiretroviral drugs, numerous other approaches have been explored to promote immune system recovery or ‘reconstitution’. For further information, see Restoring the immune system.