THURSDAY, May 17, 2001 (HealthDayNews) -- The drug that helps heroin addicts get over their addiction may also spur infection by the virus that causes AIDS, a new study shows.
Though methadone can stimulate infection of human immune system cells by the HIV virus, the researchers say their finding should not deter methadone use in drug treatment programs.
"This is all in vitro (in cell cultures), so we cannot come out and say that these people shouldn't take methadone. That would be a disservice," says Dr. Steven Douglas, chief of the section of immunology at the Children's Hospital of Philadelphia and a member of the team reporting the finding.
Instead, Stevens says, "The conclusion is that drug abusers with opiate dependence should be monitored closely for changes in their immune cells."
About 140,000 Americans are in methadone treatment for their heroin addiction.
The researchers say their finding is not a surprise, because opiate drugs, including heroin and morphine, are known to stimulate the reproduction of HIV in human immune cells. Methadone is a synthetic opiate with many properties of heroin and morphine. The finding was presented yesterday at an international conference of the PsychoNeuroImmunology Research Society in Utrecht, The Netherlands.
That similarity between the natural and synthetic drugs spurred the researchers to study the interaction of HIV with microglial cells and macrophages, two important classes of immune system cells that can be reservoirs for the virus. Adding methadone to colonies of the cells grown in the laboratory increased the ability of HIV to infect them, the study found.
When the researchers added methadone to cultures of blood cells from HIV-infected patients in which the virus was not reproducing itself, the latent HIV infection began to replicate.
The researchers found possible mechanisms for the methadone-HIV interaction. Methadone increases the activity of receptors in the cell membrane, allowing HIV to enter the cell, they say. Inside the cell, it activates a promoter gene that switches HIV infection from a latent to an active state.
More work is needed to show whether the laboratory work reflects how HIV infection progresses in people getting methadone, the researchers say.
The report is interesting as a research finding, says Dr. Beverly Richman, chief of medical services at the Beth Israel Medical Center Methadone Maintenance Treatment Program in New York City. But she says Douglas is correct in saying that the findings should not interfere with such programs because methadone clearly reduces the risk of HIV infection.
"What we do know is that if, instead of being on methadone, [addicts] use intravenous drugs, they are put at more risk of HIV infection," Richman says. "Infected needles can spread HIV, and IV-drug use also impairs the immune system. On a clinical level, methadone should normalize an individual's immune system."
What To Do
To find out what clinical trials are being done on AIDS, check Veritas Medicine.
For more information about methadone maintenance, check the National Alliance of Methadone Advocates or the National Institute on Drug Abuse.
Or, read previous HealthDay stories.
