2024-07-19 11:26:49
Success at Berlin Charité
Another person cured of HIV – and cancer
Updated on 18.07.2024 – 18:15Reading time: 3 min.
Worldwide, fewer than ten people are considered to be cured of HIV. In Germany, there have been two patients so far. Now researchers are reporting on a third – which could point to a new way of healing.
According to the Berlin Charité, another HIV patient has been cured. Despite discontinuing antiviral therapy, no HIV virus has been detectable in the man referred to as the “second Berlin patient” for more than five years, the researchers involved at the Charité announced. This makes him the third person in Germany and – depending on how you count – the sixth or seventh person worldwide to be cured. Timothy Brown, previously known as the “Berlin patient”, was the first person to be cured of the HIV virus more than 15 years ago.
The “second Berlin patient” now presented, a 60-year-old man, tested positive for HIV in 2009, according to the Charité. In 2015, he was also diagnosed with acute myeloid leukemia (AML), a form of blood cancer. In addition to chemotherapy, he also needed a stem cell transplant.
HIV stands for “Human Immunodeficiency Virus”. An infection with the HIV virus damages certain cells of the immune system and makes the body more susceptible to diseases. If left untreated, an infection with the HIV virus can lead to AIDS. AIDS stands for “Acquired Immunodeficiency Syndrome”.
He was given stem cells from a healthy donor, including the immune system. “The donor’s immune system takes over control, so to speak,” explained Olaf Penack, senior physician at the clinic specializing in hematology, oncology and tumor immunology. What is special about this case is the treatment method, said Christian Gaebler, head of a working group at the Charité’s Clinic for Infectious Diseases and Intensive Care Medicine.
The HIV virus attacks the body’s immune cells at certain docking sites, the so-called CCR5 receptors. According to the Charité, around one percent of the European population has a mutation of these CCR5 receptors, the so-called Delta-32 mutation. This prevents the virus from penetrating – those affected are considered naturally immune to HIV.
In the case of the first “Berlin patient” who was considered cured of HIV, it was possible to find a stem cell donor whose tissue characteristics matched the recipient and who carried the immunity-giving mutation. The stem cell donation transferred his immune system, including the mutation. Four other people worldwide have been treated in this way and are considered cured. The treatment is risky; according to the Charité, the risk of death due to therapy is around ten percent. If it is successful, it fights both the HIV virus and the cancer.
The “second Berlin patient” took a slightly different approach. No suitable HIV-immune person was found for the stem cell donation. However, the donor had “in addition to the normal version of the CCR5 receptor on her cells, also the mutated version of the docking site,” said Penack, who also treated the first “Berlin patient.” This is the case when a person inherits the Delta-32 mutation from only one parent. However, this does not confer immunity against the HIV virus.
After the stem cell donation, the patient also received a so-called antiretroviral therapy against the virus. This prevents further production of the virus, but has no effect on existing virus reservoirs that have formed after the infection. “These virus hiding places are the biggest hurdle in research into a cure for HIV,” explains Gaebler.
The patient stopped the antiviral therapy of his own accord in 2018. He had long been convinced that he was cured, the researchers reported. Since then, there has been no evidence of renewed virus replication, said Gaebler: “We were all very surprised and pleased.” The researchers are currently investigating how the success can be explained. One factor could be that the patient’s immune system was very quickly replaced by the donor’s immune system, said Gaebler.
It is estimated that around 39 million people worldwide are living with HIV infections. Cures are very rare. If you include one case where the follow-up period is relatively short, seven people worldwide are currently considered to be cured of HIV.