Gene variant 'ups HIV risk by 40%'
The gene variant is common in people of African descent
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Thursday, 17, Jul 2008 08:49
A gene variant that evolved to protect people against malaria has been found to increase susceptibility to HIV infection by up to 40 per cent.
Researchers also discovered that the same variant, which is common in people of African descent, appears to prolong survival of those infected with HIV by about two years.
As such the scientists behind the study, published in the journal Cell Host & Microbe, described the genetic variant as a "double-edged sword".
The team from University College London (UCL), South Texas Veterans Health Care System and University of Texas made the discovery after analysing data from a 25-year study of thousands of Americans of different ethnic backgrounds.
They focussed on a gene that encodes a binding protein found on the surface of cells, called Duffy Antigen Receptor for Chemokines (DARC).
The variation of this gene means that they do not express DARC on red blood cells.
DARC influences the levels of inflammatory and anti-HIV blood factors called chemokines.
"The big message here is that something that protected against malaria in the past is now leaving the host more susceptible to HIV," said Professor Robin Weiss from UCL.
"In sub-Saharan Africa, the vast majority of people do not express DARC on their red blood cells and previous research has shown that this variation seems to have evolved to protect against a particular form of malaria. However, this protective effect actually leaves those with the variation more susceptible to HIV."
Lead author of the study, Professor Sunil Ahuja from the University of Texas, added: "It turns out that having this variation is a double-edged sword. The finding is another valuable piece in the puzzle of HIV-Aids genetics."