HIV Digest	HIV Digest Archive

Hopes that the drug therapies that miraculously changed HIV from a death sentence to a chronic infection might eventually eradicate every trace of infection from the body proved short-lived. And investigation into where and how the virus hides uncovered one of the biggest disappointments in AIDS research.

Dr. Robert Siliciano of Johns Hopkins University regularly tests the blood of 50 Baltimore AIDS patients to measure the virus' persistence despite the best treatments. "What HIV has done is tap into the most fundamental aspect of the immune system, and that is its immunological memory," he said. Siliciano said the virus lies silent inside resting memory T cells, whose job is to store a record of the germs they encounter to keep the body ready for return battles. Inside these sleeping cells, HIV lies dormant but dangerous. The cells do die off, but very slowly. Based on data from his Baltimore patients, Siliciano estimated that it would take 73 years for the cells to die off- and he can imagine no way to speed the process.

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Dr. David Ho of the Aaron Diamond AIDS Research Center is working on a new project, code numbered 377, to attack the hiding virus. About 30 of his patients are receiving a new four-drug combination whose goal is to stop low-level circulation of the virus, which in turn should shut off the supply of infected memory cells. If it works, Ho believes the therapy could wipe out the body's HIV-infected memory T cells in three to four years.

"No one would say that once we get rid of this reservoir, we have a cure," said Ho. "We have confronted a difficult problem, but there may be others." Among these might be that the memory T cells are not the body's only long-lived reservoir of HIV. The virus may also linger in other places that are hard to check or are beyond the reach of AIDS drugs, such as the brain, bone marrow and testes.

Editor's Note: from the Wall Street Journal