A German man has been cured of HIV, a medical milestone that only six other people have achieved since the AIDS epidemic began more than 40 years ago.
The German man, who preferred not to be identified, was treated for acute myeloid leukemia, or AML, with a stem cell transplant in October 2015. He stopped taking his antiretroviral drugs in September 2018 and remains in viral remission with no relapses. Multiple ultrasensitive tests have not detected viable HIV in his body.
In his statement regarding his recovery from his illness, the man said, “A healthy person has many wishes, while a sick person has only one.”
The case, which the researchers say offers vital lessons for HIV cure research, is expected to be presented Wednesday at the 25th International AIDS Conference in Munich by Dr. Christian Gaebler, a physician-scientist at Charité-Universitätsmedizin Berlin.
“The longer we see these HIV remissions without HIV treatment, the more confident we can be that we’ve probably seen a case where we’ve eliminated all the capable HIV,” Gaebler said.
As with all previous cases of potential HIV cures, experts are keen to temper public excitement with a caveat: The treatment, which appeared to block the virus in seven patients, will be available only to a select few. All of them contracted HIV and later developed blood cancers that required stem cell transplants to treat malignancies.
In most cases, transplants from donors selected for their immune cells, the cells targeted by HIV, displayed a rare natural resistance to the virus and appeared to be effective in eliminating all viable or competent copies of the virus from the body.
Stem cell transplants are highly toxic and can be fatal, so it would be unethical to provide them to people with HIV except to treat individual diseases such as blood cancer.
HIV is very difficult to treat because some of the cells it infects are long-lived immune cells that are dormant or have gone dormant. Standard antiretroviral therapy for HIV only works on the immune cells that typically actively produce new viral copies in infected cells. As a result, HIV in resting cells remains under the radar. Collectively, such cells are known as viral reservoirs.
At any time, a reservoir cell can start producing HIV, so if people with the virus stop taking their antiretrovirals, their viral load usually returns within a few weeks.
Stem cell transplantation has the potential to cure HIV because it involves destroying a person’s cancer-affected immune system with chemotherapy and sometimes radiation and replacing it with a donor’s healthy immune system.
In five out of seven cases of definite or probable HIV cure, doctors found donors with rare, natural defects in both copies of a gene that leads to a specific protein called CCR5 on the surface of immune cells. Most strains of HIV bind to this protein to infect cells. Without functional CCR5 proteins, immune cells are resistant to HIV.
The German man’s donor had only one copy of the CCR5 gene, meaning his immune cells likely had about half the normal amount of this protein.. He also had only one copy of the gene. Together, those two genetic factors may have increased his chances of a cure, Gaebler said.
Having two copies of the faulty CCR5 gene is rare, occurring in about 1% of people of Northern European descent, compared to about 16% of people with one copy.
“So the study suggests that we can expand the donor pool for these types of cases,” Dr. Sharon Lewin, director of the Peter Doherty Institute of Infection and Immunity in Melbourne, Australia, said at a media briefing last week.
Interestingly, a man treated in Geneva, where a possible HIV cure was announced last year, had a donor with two normal copies of the CCR5 gene, meaning the transplanted immune cells were not resistant to HIV.
Two recent cases in Europe raise critical questions about the factors that actually contribute to successful treatment of HIV.
“The level of protection that could be predicted from transplantation would not have been sufficient to prevent the virus from surviving and reemerging,” says Dr. Steven Deeks, a leading HIV treatment researcher at the University of California, San Francisco, who was not involved in the German man’s care. “There are several testable theories, so I am optimistic that we will learn something here that could inform the next generation of treatment efforts.”
Having HIV-resistant immune cells in the mix certainly greatly increases the chances of success in treating the virus with a stem cell transplant, Gaebler said. Still, he said, not having that safety net — or having a network with some gaps, as in the German man’s case — doesn’t preclude success.
“We need to understand how the new immune system successfully established itself in his body and how it successfully eliminated the HIV reservoirs over time,” he said. “The donor’s innate immune system may have played an important role here,” he said, suggesting that the transplanted immune cells may have attacked the viral reservoir.
Another 6 people are cured or probably cured of HIV
All were initially known by nicknames based on where they were treated.
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Adam Castillejo, aka the “London patient.” Castillejo, a 44-year-old Venezuelan living in England, received a stem cell transplant for AML in 2016 and stopped HIV treatment in 2017. He is believed to be in remission.
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Marc Franke, the “Düsseldorf patient”. Franke, 55, who underwent a stem cell transplant for AML in 2013, stopped taking antiretroviral drugs in November 2018 and is considered to be in remission.
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Paul Edmonds, aka the “City of Hope patient.” Edmonds, who was 63 when he received a stem cell transplant for AML in 2019 and was the oldest person with a potential cure, received low-intensity chemotherapy because of his age. He has been off antiretrovirals since March 2021 and will be considered cured after five years without a viral rebound. In an interview, he expressed excitement for the new case of a man who is likely cured, saying, “My vision is clear: a world where HIV is no longer a sentence, but a footnote in history.”
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“The New York patient.” The patient, who is likely the first mixed-race woman and person to be cured, was diagnosed with leukemia in 2017 and underwent a stem cell transplant enriched with umbilical cord blood, which was less genetically compatible with her donor, thus expanding the donor pool.
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“The Geneva patient.” The patient, in his 50s, was diagnosed with a rare blood cancer in 2018 and has not been treated for HIV since November 2021. Researchers are cautious about his treatment status because his immune cells are not resistant to HIV.
Franke, Edmonds and Castillejo, who are friends, are expected to attend an HIV conference in Munich.
This article was originally published on NBCNews.com