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Being Alive
MEDICAL UPDATE: IL-2: The State of the Art
Mark Katz MD and reported by Jim Stoecker
February 5, 1994
Being Alive 1994 Feb 5: 5

Interleukin-2 (IL-2) is a cytokine, a chemical found in the body. IL-2 is known to increase CD4 and CD8 cells. In addition, it can also boost Natural Killer cell activity and gamma interferon production. In fact, IL-2 is about the best CD4 stimulant that we currently have available.

Although there have been a series of small studies using IL-2 as treatment for HIV disease, the FDA has not yet approved its use for this purpose. In 1991, however, it did approve IL-2 as treatment for renal or kidney cancer.

The big question is whether IL-2 is tolerable therapy at the dose level needed for efficacy. Side effects include fever, malaise, edema and liver damage.

The National Institute of Allergies and Infectious Diseases (NIAID) is conducting a small, ongoing Phase I trial. In this protocol, IL-2 is continuously infused for five days every two months over a period of one year. Seven of the ten study participants with CD4 count over 200 report over a 25% increase in T-cells. The thirteen with CD4 count under 200 have all required dose reduction because of side effects. However, CD4 levels seemed to be raised even for those with less than 200 T-cells.

Currently, IL-2 must be infused continuously to have an effect and this limits its practicality as an immune boosting therapy. A form of IL-2 known as PEG IL-2, which is given as a subcutaneous injection, is being developed. Whether it will be as effective as the infusion is not yet known.

As with all immune boosters, we need to question whether IL-2 by raising CD4 levels will only provide more targets for the virus. Will it in fact activate HIV replication? If so, can AZT or other antivirals hold this in check? Finally, there is still the unanswered question: does increased CD4 count translate to longer survival? Our sense is that it does, but we lack the scientific evidence. Nonetheless, research on IL-2 needs to go forward. For a complete treatment of HIV disease, we need both antivirals to stop the virus from spreading and immune boosters that restore what the virus may already have destroyed.