Chronically infected HIV patients can mount anti-HIV immune response

Contrary to existing dogma, people with chronic HIV infection can mount an antiviral response, and low daily doses of interleukin 2 augment this response, according to the results of two studies led by Dr. Kendall A. Smith of Cornell University, Ithaca, New York. These findings are published in the November/December issue of HIV Clinical Trials.

In one study, the investigators found that chronically infected patients who receive interrupted highly active antiretroviral therapy (HAART) and daily low-dose IL-2 demonstrate antiviral reactivity. Viral relapse occurred after cessation of HAART, the investigators found, but after peak concentration, “viraemia then declined an order of magnitude coincident with a 2-fold lymphocytosis of the CD8+ T-cell subset. A second treatment interruption resulted in attenuation of the peak and trough virus concentration by greater than 10-fold in three of four subjects, while the CD8+ T-cell concentrations remained elevated.”

“The dogma has been, up until this study, that chronically infected people have suffered irreparable damage to their immune system so that they are never going to be able to recognize and control the virus,” Dr. Smith commented. He stated that the study data indicates these conclusions to be false. “Other investigators, who have examined HAART interruption, have restarted antiviral therapy if viral loads went above a certain level,” Dr. Smith said. These researchers “haven’t waited long enough and may have missed the down slope” in viral levels, he explained.

In the other study, Dr. Smith and others found that daily low-dose subcutaneous IL-2 combined with HAART is safe and effective for expanding lymphocyte cell types in patients with CD4+ counts less than 300. Other investigators have championed IL-2, but these studies have used much higher doses with significant side effects, the researchers point out.

The new method is a “gentler, friendlier approach to accelerating immune system recovery,” Dr. Smith emphasized. “We are standing on a new threshold now – a threshold of understanding that this isn’t the end of the line – that there is a lot of antiviral reactivity on the part of individuals that we can now hopefully manipulate.”