New aggressive form of HIV discovered in Cuba

A new aggressive form of HIV can progress to AIDS in just three years - so rapidly that patients may not even realise they were infected, scientists say. Engaging in unprotected sex with multiple partners increases the risk of contracting multiple strains of HIV. Once inside a host, these strains can recombine into a new variant of the virus, researchers said.

One such recombinant variant observed in patients in Cuba appears to be much more aggressive than other known forms of HIV, researchers said. Before it can enter human cells, HIV must first anchor itself to them. The virus does this via anchor points, or co-receptors, 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.

Researchers at KU Leuven's Laboratory for Clinical and Epidemiological Virology in Belgium have described 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 drastically the healthy phase and triggering rapid progression to AIDS.

Professor Anne-Mieke Vandamme and colleagues studied the blood of 73 recently-infected patients - 52 at AIDS diagnosis and 21 without AIDS - and compared results with blood from 22 patients who had progressed to AIDS after a normal healthy period with HIV.

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.

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