Chuck Bednar for redOrbit.com – @BednarChuck
A new, more aggressive strain of HIV has been discovered in Cuba, and researchers warn that it progresses into AIDS so quickly that antiretroviral treatments may prove ineffective.
Anne-Mieke Vandamme, a medical professor at Belgium’s University of Leuvan, explained to UPI that HIV infection typically takes between five and 10 years to turn into full-blown AIDS. However, the new strain apparently does so within three years of initial infection.
Vandamme and her colleagues, who report their findings in the journal EBioMedicine, said that they were alerted to the more aggressive HIV strain by Cuban health officials seeking answers. Her team studied over 70 patients and divided them into different groups, including one made up of patients infected with the mutated strain that developed AIDS in less than three years.
“We have a collaborative project with Cuba and the Cuban clinicians had noticed that they recently had more and more patients who were progressing much faster to AIDS than they were used to [seeing],” the professor explained to Voice of America.
“In this case, most of these patients had AIDS even at diagnosis already,” she added. “So this group of patients that progressed very fast, they were all recently infected. And we know that because they had been HIV negative tested one or a maximum two years before.”
Typically, she explained, the rate at which HIV becomes AIDS is the result of a patient’s immune system (namely the scarcity of CD-4 immune cells) and the number of opportunistic infections a patient has. However, what they found in Cuba was something completely different – a variant of HIV that was found only in the group which was progressing more quickly.
“We focused in on this variant [and] tried to find out what was different. And we saw it was a recombinant of three different subtypes,” Vandamme explained. “Another thing was that they had much more virus in their blood than the other patients. So, what we call the viral load was higher in these patients.”
Introducing…CRF19
The new form of HIV, which has been named CRF19, is a combination of sub-types A, D and G, the researchers discovered. Patients with CRF19 were also found to have elevated levels of a molecule called RANTES, which is released by the immune system to warn about the infection.
So why does this type of HIV progress to AIDS so rapidly? Vandamme explained that, in order for infection to occur, the virus has to attach itself to a cell at points known as co-receptors. HIV can use two types of co-receptors, CCR5 or CXCR4, and when it is progressing normally, it goes from CCR5 to CXCR4 several years later, which speeds up the progression to AIDS.
Ordinarily, that takes several years to occur, but not in the new variant form. The new virus takes less than three years, and the study authors believe that the presence of HIV subtype D in the variant could be the key. That subtype contains an enzyme which enables HIV to reproduce in greater numbers, and its steals proteins from other subtypes for use in new virus particles.
The good news, according to Vandamme’s team, is that the aggressive form of HIV responds to most types of antiretroviral drugs. Unfortunately, the rapid progression of the variant increases the risk that patients may not be aware that they have full-blown AIDS until it’s too late for such treatments to do any good.
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