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The human immunodeficiency viruses (HIV) are two species of Lentivirus (a subgroup of retrovirus) that infect humans. Over time, they cause acquired immunodeficiency syndrome (AIDS), a condition in which progressive failure of the immune system allows life-threatening opportunistic infections and cancers to thrive. Without treatment, average survival time after infection with HIV is estimated to be 9 to 11 years, depending on the HIV subtype. Read more...
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Watch the following video (00:00 - 01:48). Feel free to use subtitles if you need them. (Note: This video is different from the one on Madoc)
Have we had it all back to front? Ten years ago, a man known as the Berlin patient was cured of HIV. It was thought that a bone marrow transplant he received for cancer, from a person immune to HIV, had eradicated the virus from his body. But evidence from a new group of people suggests an immune reaction provoked by the transplant may actually have been responsible.
The Berlin patient —Timothy Brown— is still the only person who seems to have remained free from HIV for a long period. A few other people have been "functionally cured" —although they have some dormant virus in their cells, they no longer need to take antiviral therapy.
HIV targets immune cells, leaving people defenceless against other infections if it goes untreated. The standard view was that Brown was cured by a bone marrow transplant he received to treat his leukaemia.
The bone marrow came from someone with a genetic mutation in the CCR5 gene that makes immune cells resistant to HIV. But some believe that a side effect of the transplant may actually have been at least partly responsible for wiping out the virus in his body.
Known as graft-versus-host disease, it is caused by immune cells from the donor attacking those of the recipient. Brown's bone marrow transplant triggered this, causing his own immune cells —and the HIV they contained— to be killed.
"Six more people with HIV and cancer who have been treated in the same way as Brown now seem to have no trace of the virus in their system", says Javier Martínez-Picado from IrsiCaixa AIDS Research Institute in Barcelona, Spain. Only one of the six received bone marrow from a person with the CCR5 mutation —however, all six developed graft-versus-host disease.
"We won't know if the six people have completely cleared their bodies of HIV until they stop taking their anti-HIV drugs. That may happen for the first person within the next year", says Martínez-Picado.
"If the theory is right, that would be tremendous", says Annemarie Wensing of the University Medical Center Utrecht in the Netherlands, who presented data on two of the six at the European Congress of Clinical Microbiology and Infectious Diseases in Vienna last week. All HIV tests on the six have been negative for more than two years.
A different approach for treating HIV has recently shown promise. Known as "kick and kill", this treatment wakes up dormant virus that has been hiding in a person's cells and then targets it. This has enabled five people to stop taking anti-HIV drugs, but the virus is still present in some of their immune cells.
That's not so for Brown or the six newer cases, who come from various countries.
If graft-versus-host disease does turn out to wipe out HIV, doctors would be reluctant to deliberately provoke this potentially fatal condition in people. An international consortium of researchers, including Wensing and Martínez-Picado, has been following 23 people with HIV who received bone marrow transplants to treat cancer. So far, about half have died —either from the transplant, or their cancer.
Current anti-HIV drugs mean that people in rich countries can largely keep HIV under control, so inciting graft-versus-host disease wouldn't be a desirable option.
"But the consortium is studying the transplant recipients to learn more about where HIV hides. This should help develop a cure without the need for a bone marrow transplant", says Martínez-Picado.
Read original article by Clare Wilson here:
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March 10, 2020
A man in London appears to be the second person ever cured of HIV, his doctors said.
The man —whose case was first announced a year ago— has now been HIV-free for 30 months without the need for antiviral medications, according to a new report published Tuesday (March 10) in the journal The Lancet HIV. Continue reading...
1. Timothy Brown went through two colonoscopies and agencies found HIV in his colon.
2. It has initially been assumed that the bone marrow transplant Brown received was what lead to the virus being eradicated.
3. He is to this day one of a few people who seem to have received a sterilizing cure.
4. The key to this success was attributed to the fact that the bone marrow donor had been vaccinated again HIV.
5. Yet recent research suggests a side effect of the transplant might have played a part in achieving this result.
6. This side effect is known as transplant rejection.
7. A similar protocol has been applied to six patients in the Netherlands, which to this day seems to have proved successful.
8. The “kick and kill”, or “shock and kill” approach, aims at destroying viral reservoirs, so patients can stay off anti-retroviral therapy.
9. Deliberately inducing Grafton-versus-host disease is an option that could soon become large scale.
10. According to Martinez-Picado, combining discoveries and advances about Grafton-Versus-Host disease and "kick and kill" could be key to developing a cure.
Play against other students. Complete the following sentences with the missing words.