Newly discovered HIV reservoir could point the way to cures

h.i.v. infected t cell
HIV can reside in macrophages in addition to T cells, UNC scientists have found. (NIAID/flickr CC BY 2.0)

Drugs that fight HIV have proven effective at suppressing the virus, but the search for a permanent cure has turned up empty so far. Most of that research has focused on finding ways to wipe out the virus from the immune system’s T cells.

Now a discovery by scientists at the University of North Carolina suggests that a different approach is in order.

Researchers from UNC’s division of infectious diseases have discovered that HIV persists in macrophages—large white blood cells that reside in the brain, bone marrow, liver and many other tissues in the body. They published their findings in the journal Nature Medicine.

The discovery builds on mouse studies at UNC’s school of medicine that showed the ability of macrophages to foster the replication of HIV, even when T cells are not present. In this new study, the scientists demonstrated that anti-retroviral therapies commonly used to treat HIV suppressed this replication, but that when the treatment was stopped, the virus rebounded.

"The fact that HIV-infected macrophages can persist means that any possible therapeutic intervention to eradicate HIV might have to target two very different types of cells," macrophages and T cells, said lead author Jenna Honeycutt, a post doctoral researcher at UNC, in a press release.

Researchers around the world are searching for new approaches to fight HIV by targeting T cells. Last October, for example, scientists at the University of California at San Francisco announced they have developed a CRISPR gene-editing platform to modify immune cells so they can fight the infection. And a team at Temple University previously showed they could use CRISPR to eliminate HIV from T cells.

The next step for the UNC team will be to scrutinize macrophages so they can determine how they support HIV persistence. That effort will include figuring out where in the body HIV-infected macrophages hide during treatment and how they might respond to care aimed at eliminating the virus.