"Cure" for AIDS Stumbled Upon?

Doctors in Berlin, Germany, are reporting that a 42-year-old American living in that city may have eliminated the virus from his body after a bone marrow transplant.

According to the Wall Street Journal report, the man was suffering from leukemia and AIDS, and while he continues to receive treatment for the leukemia, the virus has not reappeared in his blood in 600 days.

Traditionally, when a person on antiretroviral medication to treat HIV stops taking the pills, the virus bursts back with a flurry of activity. But this unidentified patient stopped taking the medication and has not had any evidence of the virus in his blood since.

The report explains that doctors believe this is due to the man's leukemia doctor's use of bone marrow from a donor who had genetic immunity to HIV infection.

The development suggests a potential new therapeutic avenue and comes as the search for a cure has adopted new urgency. Many fear that current AIDS drugs aren't sustainable. Known as antiretrovirals, the medications prevent the virus from replicating but must be taken every day for life and are expensive for poor countries where the disease runs rampant. Last year, AIDS killed two million people; 2.7 million more contracted the virus, so treatment costs will keep ballooning.

So what does this case indicate to experts? The Journal reports:

While cautioning that the Berlin case could be a fluke, David Baltimore, who won a Nobel prize for his research on tumor viruses, deemed it "a very good sign" and a virtual "proof of principle" for gene-therapy approaches. Dr. Baltimore and his colleague, University of California at Los Angeles researcher Irvin Chen, have developed a gene therapy strategy against HIV that works in a similar way to the Berlin case. Drs. Baltimore and Chen have formed a private company to develop the therapy.

"Sounds like good news so far -- I'd be hesitant to call it a cure," Mark Peterson of the Michigan Positive Action Coalition, or MI-POZ, a group of politically active HIV-positive people in Michigan, said in an e-mail. Peterson went on to say that the news underscored the importance of research into a specific class of drugs that stop the virus from invading human cells in the first place.

This is possibly very important news in the fight against HIV.

When antiretrovirals were first introduced, and viral loads (the number of viral particles in the blood) were found to have been suppressed to undetectable, doctors thought that eventually cells harboring HIV would die off and the person would be HIV-free. That did not happen. Researchers discovered that the virus incorporated itself into the genetic makeup of the infected person and waited for the opportunity to reignite the infection.

But in 1996, researchers also made another startling discovery, the Journal reports:

... researchers discovered that some gay men astonishingly remained uninfected despite engaging in very risky sex with as many as hundreds of partners. These men had inherited a mutation from both their parents that made them virtually immune to HIV.

The mutation prevents a molecule called CCR5 from appearing on the surface of cells. CCR5 acts as a kind of door for the virus. Since most HIV strains must bind to CCR5 to enter cells, the mutation bars the virus from entering. A new AIDS drug, Selzentry, made by Pfizer Inc., doesn't attack HIV itself but works by blocking CCR5.

Craig Covey, executive director of the Midwest AIDS Prevention Project based in Ferndale, said he had not heard anything about the case or the reports, and was unable to comment.