Can we win against HIV?

HIV, the AIDS virus (yellow), infecting a human cell. Image by National Cancer Institute (CC BY 2.0)

There is currently no cure for Human Immunodeficiency Virus (HIV). Why is that the case? HIV is tricky, it attacks its killer – our immune cells. Like any virus, HIV needs a host to multiply, so it incorporates its DNA into our genome and uses our immune cells to reproduce[1].

Is it possible to win against HIV? Yes, according to a few patients who became world-famous for getting rid of the virus! Some of their cells might still be harbouring HIV, however, these patients had no active HIV detected so far.

The first to be cured of HIV were the Berlin and London patients. They were diagnosed with cancer and underwent bone marrow and stem cell transplantation, respectively. Crucially, both transplants lacked the CCR5 gene necessary for most HIV viruses to infect human cells[2]. Essentially, these transplants ‘updated’ patients’ immune system to make it HIV-proof.

On the other hand, the San Francisco and Esperanza patients seem to have won against HIV all on their own. Both belong to under one percent of HIV patients known as ‘elite controllers’, whose immune system keeps HIV under control without medical help. The Esperanza patient was treated with antivirals for six months during her pregnancy to prevent passing HIV to her foetus. Surprisingly, no HIV has been found in billions of her cells ever since[3]. As for the San Francisco patient, Loreen Willenberg was diagnosed with HIV in 1992 but had consistently undetectable levels of HIV for decades. Some traces of viral DNA were found in Loreen’s cells once, but they were too damaged to make new viruses[4].

What is so unique about these patients’ immune system and what can we learn from them? It turns out their immune system eliminated cells with viral genes incorporated into the accessible parts of the human genome. As for the detected viral DNA traces, they are incorporated into remote regions of the elite controllers’ genome, making it impossible for the virus to replicate[5].

At present, there is no pressure to find a cure for HIV as currently available antiviral treatments are highly effective. However, HIV patients must strictly adhere to treatment plans and take antivirals for the rest of their life to suppress dormant HIV. Some face severe side effects. Elite controllers give us hope that by studying their cases we can come closer to figuring out how to eliminate HIV for good.

Edited by Liam Butler
Copy-edited by Claire Thomson







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