Another proposed strategy is to ‘flush’ HIV out of latently infected cells. Since HIV can only replicate in activated cells, ‘waking up’ inactive cells could force it to produce new virus particles that are susceptible to current antiretroviral drugs.

Several methods have been tried to stimulate inactive cells infected with HIV. Some studies have shown that the immune system chemical messenger interleukin-7 (IL-7) and a protein kinase activator called prostratin can trigger resting CD4 T-cells to produce HIV without stimulating activation of all T-cells^[1].

Interleukin 2 (IL-2) has also been studied for this purpose. Although some researchers found that IL-2 reduced the pool of HIV-infected resting CD4 T-cells, others did not see this effect^[2][3][4]. Similarly, granulocyte-macrophage colony stimulating factor has been proposed for flushing HIV out of infected macrophages.

Researchers also studied valproic acid (Depakote / Convulex), a drug used to treat epilepsy and bipolar disorder. Test tube studies showed that valproic acid could stimulate the release of HIV from inactive cells, and in a small proof-of-concept study, patients using valproic acid plus HAART experienced declines in the number of resting HIV-infected cells ^[5]. More recently, however, Siliciano’s group found that nine patients taking HAART plus valproic acid for at least three months did not have lower numbers of latent infected cells, and the level did not decrease over time^[6].