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If you were born between 1965 and 1970, you likely witnessed the beginning of the AIDS crisis and heard about the first HIV cure 15 years ago. Back then, American Timothy Ray Brown became the first person cured of HIV at Berlin’s Charité hospital. Now, in 2024, a second person has been successfully cured of HIV there.
First HIV Cure Thanks to Receptor Mutation
During an infection, the HIV virus targets immune cells in your body through specific docking sites known as CCR5 receptors. According to Charité, approximately 1% of people of European descent possess a mutation in these CCR5 receptors, known as the Delta-32 mutation. This mutation prevents the virus from entering the cells, making carriers naturally immune to HIV.
In the case of the first HIV cure at Charité, Timothy Ray Brown, who was diagnosed with HIV in 1995 and later with leukemia in 2006, received a stem cell transplant from a donor with both compatible tissue characteristics and the Delta-32 mutation. This transplant not only replaced Brown’s immune system but also transferred the mutation to him.
Timothy Ray Brown passed away in 2020 at the age of 54, but his death was due to a recurrence of leukemia, not a reactivated HIV infection.
New Approach in the Second HIV Cure at Charité
Recently, a second HIV cure was achieved at Charité in a 60-year-old patient. Diagnosed with HIV in 2009 and acute myeloid leukemia (AML) in 2015, the patient underwent chemotherapy and a stem cell transplant. However, no donor with the Delta-32 mutation could be found. Instead, the donor carried both a normal version of the CCR5 receptor and a mutated version, inherited from one parent. While this partial mutation doesn’t provide HIV immunity, it opened the door to a new approach.
The patient received the stem cell transplant in 2015 along with antiretroviral therapy (ART) to suppress HIV replication. This therapy effectively stopped new virus production but couldn’t eliminate existing virus reservoirs formed after infection. Such reservoirs are considered one of the biggest challenges in HIV cure research.
In 2018, the patient independently discontinued ART, feeling healthy for an extended period. Follow-up examinations revealed no signs of a viral rebound. While the exact mechanism of this cure remains unclear, researchers speculate that the rapid replacement of the patient’s immune system by the donor’s cells played a crucial role.
HIV Cure – Challenges to Reaching the Goal
As you may know, HIV is a highly complex disease, and several factors make achieving a full cure difficult. A key challenge is the virus’s ability to integrate its DNA into the host cell’s DNA, especially in CD4+ helper T cells. This integration makes the virus a permanent part of infected cells, complicating efforts to isolate and remove it without damaging the host cells.
Infected T cells continue producing viruses by using an enzyme called reverse transcriptase to convert the virus’s RNA into DNA, which is then incorporated into human DNA by another enzyme, integrase. The human cell begins producing new virus components, which assemble into new HIV particles. These particles bud from the host cell, enter the bloodstream, and infect other cells.
To maintain immune function, the body must constantly produce new T cells. Over time, as HIV destroys more T cells, the immune system becomes increasingly vulnerable. The virus’s mutations and resistance to medications further complicate efforts to understand and counteract HIV.
HIV Cure as the Goal of Research
Globally, only seven confirmed cases of HIV cure exist among an estimated 39 million people living with HIV. These include six men and one woman, with three treated in Germany: two at Charité (the “first and second Berlin patients”) and one in Düsseldorf. These cases highlight the potential for vaccines or cell-based immunotherapies once all mechanisms are fully understood.
Stem cell therapies like those used at Charité are currently only viable for a small subset of HIV patients who also have leukemia. For otherwise healthy HIV-positive individuals, stem cell transplants carry a failure risk of around 10%, which is unnecessary given the availability of effective antiretroviral medications. Current ART allows people with HIV to live nearly normal lives with comparable life expectancies to HIV-negative individuals—79 years for men and 83 years for women, on average.
Prevention is Better Than Waiting for an HIV Cure
Despite progress at Charité, a breakthrough in HIV cure remains uncertain. Protecting yourself from infection is therefore essential. Since sexual activity is the primary mode of HIV transmission, it’s crucial to use protection, such as condoms during anal sex, to minimize risk. Avoid activities that expose your mucous membranes or open wounds to your partner’s bodily fluids. Practices like swallowing semen or receiving ejaculations during anal sex can carry a risk of transmission.
If you belong to a high-risk group, you might consider pre-exposure prophylaxis (PrEP) as an additional preventive measure. By protecting yourself, you can avoid worrying excessively about the pursuit of an HIV cure.