HIV attack theory wrong, finds study

A popular theory on how HIV attacks the body8217;s immune system is wrong, a new study has found. Scientists have long believed that HIV causes the slow depletion of healthy white blood cells8212;the T-cells which recognise infections so the body can fight them off8212;by causing infected T-cells to produce virus particles before dying. This ongoing cycle of infection, HIV production, reinfection and cell destruction has been called the 8220;runaway8221; hypothesis.

But if this were so, the T-cells would be killed off far too quickly, the researchers found. Using a simple mathematical model, researchers in the US and Britain showed the 8220;runaway8221; model would deplete the body8217;s healthy T cells in a matter of months, instead of the years it actually takes.

The results show that a 8220;slow process must be active8221; in the depletion of the T cells, the authors wrote in the current issue of the journal PLoS Medicine. Identifying this process 8220;will provide a key insight into the nature of HIV disease,8221; they concluded.