A woman from Argentina (the Esperanza patient) has become the second documented person whose own immune system may have cured her of HIV.
Tests on more than a billion of her cells found no viable trace of the infection. The finding raises the possibility that a person’s own immune system may in rare cases provide a sterilizing cure.
The findings published in the Annals of Internal Medicine journal will bring hope to the estimated 38 million people globally living with the virus.
Scientists are seeking a cure for HIV through four main branches of research: activating the body’s immune response to the virus, gene therapy, “shock-and-kill” attempts to force the virus from cells so the immune system can try to eradicate it, and “block-and-lock” efforts to keep the virus lodged in cells so it can’t replicate.
To date, researchers have successfully cured two other people therapeutically — in both cases through complex and dangerous stem cell transplants.
However, the Esperanza patient joins Loreen Willenburg to be the first people to be functionally cured of HIV by their own immune systems.
Lead investigator Dr Xu Yu has theorised that both women may have been cured because they had unusually powerful T cells, a component of the body’s immune system. Understanding that mechanism, she said, could be key to developing therapeutic vaccines that could clear out HIV without negative long-term consequences.
The Argentine woman was diagnosed with HIV in March 2013. Over eight years of follow-up, scientists searched for any viable HIV in 1.2 billion of her blood cells. They also searched 500 million placenta-tissue cells after the woman gave birth to an HIV-negative baby in March 2020. Dr Yu and her team found no intact viral sequences.
“We’re never going to be 100 percent sure there’s absolutely no intact virus, no functional virus anywhere in her body,” Yu said of the Esperanza patient. “To bring what we learn from these patients to a broader patient population is our ultimate goal.”