A study conducted by researchers at Imperial College London refutes the long-standing "runaway" theory on how HIV slowly depletes the body's capability to fight infection by attacking T helper cells, a class of white blood cells that co-ordinate the immune defences.
Scientists have for long been puzzled as to why this process of depletion of is so slow, often taking a decade or more.
According to the "runaway" hypothesis, T cells infected by HIV produce more HIV virus particles that activate more T cells, leading to an uncontrolled cycle of cell activation, infection, HIV production, and cell destruction.
But using mathematical model of the process by which T cells are produced and eliminated, the researchers have shown that if the runaway theory was correct, T helper cell numbers would fall to very low levels over a number of months, not years.
He said: "Scientists have never had a full understanding of the processes by which T helper cells are depleted in HIV, and therefore they've been unable to fully explain why HIV destroys the body's supply of these cells at such a slow rate," said Jaroslav Stark, Professor of Mathematics at Imperial College London.
"Our new interdisciplinary research has thrown serious doubt on one popular theory of how HIV affects these cells, and means that further studies are required to understand the mechanism behind HIV's distinctive slow process of cellular destruction," he added.
The researchers believe that one possible explanation for the slow pace of the process may be that the virus slowly adapts itself over the course of the infection.
They, however, stress the need for further analysis is to verify the alternative theory.
"If the specific process by which HIV depletes this kind of white blood cells can be identified, it could pave the way for potential new approaches to treatment," said Professor Stark.
The study has been published in PLoS Medicine.