How could a baby get an organ from a person living with HIV and not automatically contract the virus? The experts weigh in.
South Africa's done it again. Last week, surgeons from the Wits Donald Gordon Medical Centre became the first in the world to transplant a liver from a donor living with HIV.
In doing so, an HIV-positive mother was able to save the life of her HIV-negative baby - and make history.
Historically, people living with HIV have been banned from donating organs because the virus can be transmitted via donated tissue. Transplants were also thought to pose a risk to the health of donors living with the virus.
So far, doctors can't say for sure if the baby - now a healthy, 13-month-old toddler - contracted HIV because of the procedure or not. Preliminary tests haven't been able to say conclusively. As a precaution, the baby is still on HIV treatment and doctors say they still aren't sure when - or if - the child will stop taking antiretrovirals (ARVs).
Still confused? Experts from Wits University and its Donald Gordon Medical Centre as well as the National Institute For Communicable Diseases have the answers.
1. How long until we know for sure if the child has contracted HIV?
Because this hasn't been done before, we do not have any prior experience. At the moment, the short answer is we don't know.
It's possible that the only way we could find out for sure whether the child has HIV is if the child stopped antiretroviral therapy.
This would be risky, and we hope to explore all other avenues of HIV testing first.
If we did make such a decision, it would be in full consultation with the parents, HIV experts and the ethics committee.
For now, we have agreed to keep the child on ARVs indefinitely until we have more information.
We've received approval from Wits Human Research Ethics Committee to conduct a study on similar future cases to help answer this question.
2. If the child remains HIV negative, will you be able to say why?
In the long run, we might be able to work out why but it will involve more research into the ARVs used to prevent HIV, the way the virus lives and acts in the liver as well as how it's transmitted.
3. Does HIV 'live' differently in the liver as opposed to other organs?
Not much is known about how HIV acts in the human liver. The liver is an amazing organ - it regenerates, which means that it can grow back.
Scientists have looked at the way that HIV 'lives' in the liver of monkeys. In a small 2013 study published in the journal Virology, researchers found that in 42 primates infected with the monkey version of HIV, the virus was only replicating in the liver of one animal.
But all monkeys had the virus actively reproducing in other tissue such as their colon and glands.
We can't say that things are the same in humans, but that research does suggest that HIV might not 'live' in the liver as much as it does in other organs and tissues.
We'll be studying this as we continue with our research.
4. Historically, organ donations from living, HIV-positive people haven't been allowed. Is it the HIV infection or the "living" bit that's the problem?
Liver donation from live donors is well established and gets very good results. But it's the HIV infection that has made some transplant centres wary of the potential risks involved.
But HIV-positive persons can often be deceased donors, especially in the donation of kidneys from HIV-positive people to other people with the virus.
Before this case, we would not have usually have considered HIV-positive people as living donors, because there are some risks relating to the surgery.
However, in this single case we have shown that when the donor well-controlled HIV, is taking their medicine correctly, and does not have any other illness, then it is safe for an HIV positive person to be a living donor.
5. The Wits Transplant programme usually excludes donations from people infected with HIV because you say it jeopardises the donor's health. Surely, the recipient is more at risk because they might contract the virus?
If an organ donor isn't on HIV treatment or doesn't take their treatment properly, the amount of HIV in their blood is very high, and their immune system is likely to be weaker. This means that there could be more complications related to the transplant surgery, for instance, their wounds could become infected.
But if a person is doing well on treatment and has brought the level of HIV in their blood down to very low levels - so low that they are undetectable by standard tests - and their immune system is stronger, their risk as a donor is the same as an HIV-negative person's risk.
6. There aren't enough liver donors in South Africa. So does the country's historic transplant mean we could unlock a whole new potential organ donor pool by including people living with HIV?
This is an edited extract of a briefing document released by Wits Donald Gordon Medical Centre and the National Institute for Communicable Diseases.
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