Cytokines act to co-ordinate and control the immune system. HIV-related immune damage may be due, in part, to the interaction between HIV and cytokines.

HIV can disrupt the normal functioning and levels of cytokines, and cytokines can stimulate HIV replication. The typical pattern seen in people with HIV infection is that some cytokines are present at excessively high levels these include interleukin-1 (IL-1), IL-4 and tumour necrosis factor (TNF) while others such as IL-2 are present only at reduced levels. Elevated levels of some cytokines may cause symptoms such as weight loss, persistent fevers and diarrhoea.

One key field of HIV research is looking at the activity and function of cytokines with the aim of producing therapies which normalise cytokine function.

Therapeutic strategies

The therapeutic use of cytokines has focused mainly on supplementing levels of cytokines which are deficient, such as IL-2, and less commonly in trying to reduce the levels of those that are produced in excess.

Researchers are also investigating whether cytokines that are known to have anti-viral or other anti-infection effects in the healthy immune system can be administered as treatments for people with HIV. These potential treatments include interferons alfa, beta and gamma. They are also testing whether the colony-stimulating cytokines granulocyte colony-stimulating factor (G-CSF), granulocyte macrophage colony-stimulating factor (GM-CSF) and macrophage colony-stimulating factor (M-CSF), which boost levels of white blood cells, can help to correct low levels of those cells as a result of HIV infection or the side-effects of anti-HIV treatment or chemotherapy.

Interferon alfa, which was largely abandoned as an experimental HIV treatment in the early 1990s has sparked new interest following reports of several unrandomised studies in which it had a strong anti-HIV effect in salvage therapy and primary infection treatment. See Interferon alfa in Drugs used by people with HIV: Immune-modulating drugs for further information.

Some cytokines may facilitate or inhibit HIVs entry into CD4 T-cells. Researchers are trying to determine which cytokines, if any, can block HIV fusion and entry into cells. See Receptors, co-receptors and immunity to HIV in The immune system and HIV: How HIV damages the immune system for more details.