By: Xiu Sun
One formerly HIV-positive 66-year-old man is in long term remission after stem cell transplantation, announced by a medical team from City of Hope, California, on Wednesday. He is among a small, selected group of HIV-positive people who go into remission after a transplant, which unfortunately is not feasible for the vast majority of HIV-positive patients.
A stem cell transplant is used only on an HIV-positive patient who has developed cancer. The HIV-resistant mutation CCR5-delta 32 is not common and found in 1 in 100 people of northern European descent.
The donors who have the mutation CCR5-delta 32, are nearly immune to HIV. Cell receptor CCR5 is a protein on the surface of the CD4 T lymphocytes, an important component of the human immune system. CCR5 acts as a doorway for the HIV virus to enter the cell and attack the immune system. The CCR5-delta 32 mutation shuts the entryway, and the immune system will not be attacked by HIV.
Timothy Ray Brown, known as “the Berlin patient” is considered the first patient cured of HIV in 2007. He received stem cell transplant from donors with CCR5-delta 32 mutation to treat leukemia.
“I did not want to be the only person in the world cured of HIV” Brown wrote in a 2015 essay in the journal AIDS Research and Human Retroviruses, “I will not stop until HIV is cured,”. Brown died of leukemia unrelated to his HIV in 2020 at the age of 54.
Adam Castillejo, known as the “London patient” is the second patient cured of HIV and he made his name public in 2020. He received a bone marrow transplant with CCR5-delta 32 mutation to treat his Hodgkin’s lymphoma. Similar successes followed in patients in New York and Düsseldorf, Germany, and now in California.
Although the transplant approach is not feasible for the vast majority of the 38 million HIV patients around the world, including over 1.2 million in the United States, HIV treatment has made a revolutionary advancement. The prognosis of HIV disease has changed from a death sentence in the 1980s to a controllable chronic disease nowadays with average life expectancy and even cure in a small group of patients.
The promising gene-editing tool needs further study to ensure the efficiency and safety in human being. “The message to people living with HIV is that this is a signal of hope,” said Scully, of Johns Hopkins. “It is feasible. It has been replicated again. It’s also a signal that the scientific community is really engaged with trying to solve this puzzle.”