A team of California AIDS researchers has found the first direct clinical evidence that HIV does more than kill off T cells in the body's immune system. The skillful virus also prevents the production of new, healthy versions of these vital cells.
The scientists--from the Gladstone Institute of Virology and Immunology at UC San Francisco and from UC Berkeley--report their research results in the January issue of Nature Medicine. The study involved 21 patients.
"These studies focus our attention on the ways that HIV infection might stop the production of new T cells," said Joseph M. McCune, MD, PhD, senior study investigator and associate professor within the Gladstone Institute at UCSF.
"To treat the disease, not only do we need potent anti-retroviral drugs to stop the virus from spreading and destroying T cells, we may also need additional therapies to ensure that T-cell production starts anew."
The findings are significant in understanding the puzzle of T-cell turnover in the HIV population, an area that has remained controversial among leading AIDS researchers who have proposed different theories to explain why T-cell counts decrease during the course of HIV disease.
Scientists use "turnover" to describe the natural process of T-cell death and new cell production that takes place in all individuals but that is altered after HIV infects the body. The precise mechanism that HIV uses to derail the different parts of this process have been unclear, but the end result is a collapse of the immune system that makes the body vulnerable to the opportunistic infections that cause full-blown AIDS.
It had been previously thought by many investigators that HIV decreased the T-cell count by causing the destruction of these cells. The new studies indicate that a more important contribution to disease may be the ability to stop T-cell production.