Studying HIV Positive / AIDS-Free Individuals

Less reported than people living with AIDS, are those HIV-positive individuals who have never developed symptoms.

While more and more AIDS patients are surviving thanks to more effective combination therapies, another group of HIV-infected individuals – some who have been positive for as long as 20 years – have never gotten sick.

The answer may lie in the molecule CD28, says Dr. Dorothy Lewis at Baylor College of Medicine.

Dr. Lewis has been studying long-term survivors of AIDS and symptom-free HIV-positive individuals.

"It appears that an abundance of the CD28 molecule might keep some HIV patients from getting sick. CD28 activates and protects important immune system cells known as CD8s," says Dr. Lewis, a professor of immunology.

CD8 cells are known to contain the spread of viral infections.

Dr. Lewis believes that there are normal levels of cell death in healthy individuals, but that the loss is accelerated in AIDS patients, leading to the death of CD8 cells. This in turn may result in immune system damage and loss of HIV "containment." CD28 cell counts tend to remain normal in HIV-positive patients who do not display symptoms.

"By understanding CD28 gene regulation, we may be able to control this cell loss associated with HIV disease progression," says Dr. Lewis.

– By Ron Gilmore

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