Deuterium is incorporated into the DNA of actively dividing cells. By taking blood samples in weeks and months following the deuterium infusion and measuring the amount of deuterium remaining in the CD4+ T cell DNA at each time point, the researchers could count how many new cells were made and how long they lived.
The scientists found a marked increase in the numbers of newly made CD4+ cells in all the HIV-positive, IL-2 responsive volunteers. In two HIV-positive volunteers ?each of whom had received multiple five-day courses of IL-2 over several years ?the researchers detected CD4+ cells that lived for about three years, a result Dr. Kovacs calls “quite surprising.?/p>
Using another labeling technique, the researchers determined that IL-2 boosts the numbers of two subsets of CD4+ cells: naïve cells, those that have never encountered an infectious agent; and central memory cells, those that have encountered an infectious agent before and are primed to respond quickly if they encounter the same agent again.
The new data complement clinical observations suggesting that IL-2’s effects on HIV disease progression may become apparent only in long-term follow-up, says Dr. Kovacs. Two large, long-term efficacy trials currently underway should provide a clearer picture of the clinical impact of IL-2 on the course of HIV disease and its potential role in the management of HIV-infected patients, he adds. Information on these and other HIV clinical trials is available at www.aidsinfo.nih.gov.
Other authors on the paper include researchers from the NIH’s National Cancer Institute and the Science Applicati