Engaging in unprotected sex with multiple partners increases the risk of contracting multiple strains of the human immunodeficiency virus (HIV). Once inside a host, these strains can recombine into a new variant of the virus. One such recombinant variant observed in patients in Cuba appears to be much more aggressive than other known forms of HIV. Patients progress to acquired immune deficiency syndrome (AIDS) within three years of infection – so rapidly that they may not even realise they are infected.
Before it can enter human cells, HIV must first anchor itself to them. The virus does this via co-receptors, or anchor points, which are proteins on the cell membrane. In a normal infection, the virus first uses the anchor point CCR5. In many patients, after a number of healthy years, the virus then switches to the anchor point CXCR4. This co-receptor switch coincides with a faster progression to AIDS.
Writing in the journal EBioMedicine, researchers at KU Leuven’s Laboratory for Clinical and Epidemiological Virology have now reported a recombinant form of HIV observed in patients in Cuba that makes this transition much faster. The virus targets the anchor point CXCR4 early after infection, shortening the healthy phase and triggering rapid progression to AIDS.
In the patients infected with the HIV recombinant, the researchers observed abnormally high doses of the virus and of the defensive molecule RANTES. This molecule is part of the natural immune response and acts through binding to CCR5, to which most forms of HIV have to bind before entering the cell.
www.journals.elsevier.com/ebiomedicine