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HIV Medicines Show Unexpected Results, Harm Immune System

By Laurie Garrett

When HIV patients take medicines that control the virus, their immune systems begin to recuperate in ways that are puzzling and controversial, doctors are finding.

For example, patients recover immunity to some deadly opportunistic infections, but appear unable to fight diseases they were vaccinated for as children or to target HIV itself.

On Thursday, scientists reported that use of Highly Active Antiretroviral Therapy, or HAART, can in at least half of all HIV patients push the viral population down to undetectable levels, allowing the beleaguered immune system to reconstruct itself. But it appears the reconstructed system bears little resemblance to the immune system of a healthy individual, and it's unclear exactly how well the cells and antibodies in the system can protect HAART patients.

At the Conference on Retroviruses and Opportunistic Infections in Chicago, Dr. Brigitte Autran presented evidence on patients with advanced HIV infection. She said that after two to three years on HAART, these patients can muster reasonable numbers of immune system cells that can recognize and destroy some pathogens.

"The major indication clinically of a restored immune system is the dramatic decline in opportunistic infections that we all have seen," Dr. Constance Benson of the University of Colorado Health Science Center in Denver said.

And Dr. Jose Lopez and his colleagues proved the point by stopping preventive medication for parasitic pneumonia in HAART patients. Once the number one killer of people with AIDS, pneumocystis pneumonia is now so well-controlled that preventative medicine is unnecessary, he said.

That's the good news. But, Autran said, patients were not able to control infections for which they were vaccinated during their childhoods. Further, Autran's HAART patients could not muster immune responses against HIV itself.