Scientists first discovered the HIV virus that causes AIDS in 1983. At first, it was named HTLV-III/LAV (human T-cell lymphotropic virus-type III/lymphadenopathy-associated virus) by an international scientific committee but was later changed to HIV (human immunodeficiency virus). The virus attacks our immune system, which is responsible for protecting us from infections and diseases. Over time, the virus weakens a person’s immune system, making them extremely susceptible to infections and making it difficult to fight off diseases. For decades, scientists have been working to find a cure to fight the virus and today, they might finally have the answer.
In 2008, Timothy Ray Brown became known as the Berlin Patient after he was successfully cured of HIV.
Timothy, who is originally from Seattle, Washington, was diagnosed with the disease in 1995. Doctors gave him antiretroviral medications to stave off HIV for more than a decade, when he was diagnosed with acute myeloid leukemia. This is when his doctors decided to wipe out his immune system and rebuild it with donated stem cells. The stem cells were taken from a donor who was naturally immune to HIV. About 1% of Caucasians carry a gene mutation that triggers this natural immunity. For Timothy, it was a life changing treatment since the stem cell transplants not only knocked out his cancer, it also transferred the genetic variation to his immune system; making him immune to the HIV virus.
CCR5 is a protein that opens the door for HIV to enter blood cells.
CCR5 is a white blood cell receptor that acts as an entry point for the HIV-1 virus; the more common form of the disease. The 1% of the population who carry the two copies of the Δ32 mutation of CCR5 gene are resistant to HIV-1 infection. Δ32 is rare and for a person to receive it naturally is like winning a lifetime genetic jackpot. For years, scientists have been studying the Δ32 mutation of CCR5 gene and wondering if it will have the same effect on another person who is not resistant to the HIV-1 virus.
When Timothy Ray Brown was diagnosed with HIV and then acute myeloid leukemia, scientists decided that they would test their theory. For the test, they decided to inject stem cells from people with two Δ32 copies into HIV patients. After the stem cells were injected onto Timothy, he was miraculously cured after his immune system was able to stave off the virus. Thus, scientists were able to share the good fortune of the CCR5 gene with others.
Before the cure, Timothy was diagnosed with HIV for 13 years. The treatment cured him and gave him a new chance at life, but stem cell transplants are not as easy as his case. Not only are stem cell transplants expensive, they can be dangerous. For instance, the procedure requires knocking down a person’s immune system to prevent it from turning on the foreign cells. In Timothy’s case, he had no other choice and he naturally carried one Δ32 copy. The cure was a huge achievement for modern science but scientists wondered if they could replicate it successfully to cure other patients.
The new case, the “London patient”, was diagnosed with HIV in 2003.
The unidentified man who is only known as the “London patient”, was diagnosed with HIV in 2003 and started taking medication to control the infection in 2012. Like Timothy, the London patient was also diagnosed with cancer (Hodgkin’s Lymphoma) and was undergoing chemotherapy. In 2016, he agreed to undergo a stem cell transplant and was given a double Δ32 stem cell transfusion since his doctors were able to find a donor with the natural gene mutation.
During the stem cell transfusion, the patient was also put on ongoing antiretroviral treatment (ART) to suppress the HIV virus and stop the progression of HIV disease. ART also prevents onward transmission of HIV. Sixteen months after the stem cell transfusion, he was taken off antiretrovirals. Since then, he has been tested regularly for 18 months and not only is there no sign of the virus returning, but his white blood cells are not expressing CCR5.
While his cure proves that Timothy’s case was not just some coincidence, scientists say that the functional cure is not a complete eradicated cure. It means that a small percentage of the virus could still be present in the patient’s body, hiding quietly and cannot be treated until it is activated. The patient is undergoing constant tests to detect any presence of the virus but so far, it is virtually undetectable.
“By achieving remission in a second patient using a similar approach, we have shown that the Berlin Patient was not an anomaly, and that it really was the treatment approaches that eliminated HIV in these two people,” Professor Ravindra Gupta of University College London said in a statement.
The researchers are clear: “At 18 months post-treatment interruption it is premature to conclude that this patient has been cured”. Ongoing tests are necessary to detect any presence of the virus or to conclude that he is completely cured. Unlike Timothy, the London patient had far less severe consequences. Prof. Gupta believes that the success to eradicating the virus was also in part thanks to the ongoing chemotherapy, which temporarily destroyed fast-dividing cells so replacement could occur. So, scientists say that those with the HIV virus but not cancer, could take a long time to be cured since the two patients were nearly identical.
Another issue doctors and scientists equally face is the lack in Δ32 donors. Currently, there are not enough people who have both the Δ32 genes but there are approximately 36.9 million people worldwide living with HIV/AIDS. However, the achievement is still a breakthrough in the field of science and scientists hope to replicate the process to make it available for everyone.