Third HIV patient cleared after receiving virus-resistant stem cells

A German AIDS patient has become the third person in the world to be declared free of the virus. The 53-year-old German-born man, whose identity has not been disclosed, received a treatment that replaced his own bone marrow cells with HIV-resistant stem cells from a donor.

The typical treatment for the virus in recent years has been antiretroviral drugs. These drugs reduce the presence of the virus in the body to almost undetectable levels and prevent transmission. However, the virus, although blocked by the immune system, is still present in the body. When retrovirals are stopped, it replicates and spreads again.

Complete elimination of the virus from the organism

As reported in Nature, the new treatment completely eliminates HIV in the body. This is the case for the aforementioned third subject, who has been referred to as the “Düsseldorf Patient” to preserve his identity. The subject stopped antiretroviral therapy in 2018 and has not since redeveloped HIV.

The bad news is the patient was only able to receive the experimental treatment because he was diagnosed with leukemia. In 2013, a team led by virologist Björn-Erik Jensen at the University Hospital Düsseldorf (Germany) destroyed cancer cells in the patient's bone marrow, replacing them with stem cells from a donor with the CCR5Δ32/Δ321 mutation. This mutation prevents the CCR5 protein from being produced on the cell surface. HIV uses that protein to enter immune cells, so the mutation effectively makes the cells resistant to the virus.

"It’s not impossible"

The researchers took blood and tissue samples over the next five years, where they continued to find traces of the virus and immune cells that reacted specifically to HIV. This could imply the presence of a hidden reservoir of active virus or a "graveyard" of viral debris.

The ultimate test was to get the patient to stop taking antiretroviral therapy. "This shows that it is not impossible, but very difficult, to eliminate HIV from the body," Dr. Jensen said. The researcher noted that he has performed the treatment on other people with the same pattern of HIV infection and cancer, but it is still too early to draw conclusions and publish his findings.

Application to patients without leukemia is complicated

However, it is unlikely to be applicable to patients who do not have leukemia due to the high risk of the procedure. An especially high risk is the possibility of an individual rejecting a donor's marrow. Therefore, researchers are studying the possibility of using stem cells taken from the body itself and genetically modified to carry the CCR5Δ32/Δ322.3 mutation, eliminating the need for donor cells.

Precedents

Previously, the treatment proved effective in two other patients. The first was Timothy Ray Brown, known as the “Berlin Patient,” in 2007. Brown underwent a bone marrow transplant, although the infected cells were destroyed and replaced with stem cells from a healthy donor which had the CCR5Δ32/Δ32 mutation. After the procedure, Brown never developed HIV again, though he passed away in 2020.

In 2019, researchers made public that the same procedure appeared to have cured London patient Adam Castillejo. Last year, scientists announced that a New York patient had remained HIV-free for 14 months and could be cured, although they cautioned that it was too early to be sure.