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Immune system agent helps HIV drug
Interleukin-2 flushes virus out of hiding places
REUTERS
WASHINGTON, Nov. 15 — Throwing a natural immune system chemical into the cocktail of drugs now used to treat HIV infection helps wipe out the “safe havens” where the virus can hide, researchers said Sunday.
ADDING interleukin-2 (IL-2) to HIV drug cocktails flushes out the immune cells where the virus can hide, researchers said. Then highly active antiretroviral therapy (HAART) drugs can kill it.
“Our new data suggest that in HAART-treated patients, interleukin-2 may have a role in depleting this 'reservoir' of virus, where HIV would otherwise remain sequestered from the immune system,” Dr. Anthony Fauci, head of the National Institute of Allergies and Infectious Diseases (NIAID), which did the study, said in a statement.
The cocktail approach is resoundingly successful in most people with HIV, knocking the virus down to very low levels. But people who go off HAART see their HIV infection come bounding back.
This is because HIV attacks immune cells, which makes it especially hard to get at. All the drugs now on the market attack HIV while it is an active, replicating phase.
Some immune cells, however, go into a quiescent phase. Both they and the HIV are still, and thus not affected by the drugs. This “resting” phase can last for years.
Scientists have suggested that stimulating these resting CD4 T-cells might allow the drugs to get at the hidden virus.
So Tae-Wook Chun and colleagues at the NIAID tested the idea in 26 patients. Twelve of them got a cocktail of at least three drugs, while 14 had IL-2 added in.
Virus could be found in the 12 who did not get IL-2, but Chun's team was unable to find any live virus — virus capable of replicating — anywhere in the blood or lymph nodes of the 14 patients who got IL-2.
Interleukin-2 is a cytokine, a signaling chemical used by the immune system.
The NIAID, which announced its findings on Sunday at a meeting of the Infectious Disease Society of America in Denver, said IL-2 does not completely solve the problem of reservoirs.
The HIV virus is also believed to hide in the brain and in other immune cells known as macrophages, as well as elsewhere in the body.
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