We might have recently heard about possibly the first person ‘functionally cured’ from HIV using stem cell transplants – “A 45-year-old man now living in the Bay Area may be the first person ever cured of the deadly disease AIDS, the result of the discovery of an apparent HIV immunity gene”, from numerous broadcasting networks. The patient had both cancer and HIV and what the medical team did was to wipe out his immune system and hence make bone marrow transplant but from a unique donor.
What is exactly happening is engineering the immune system to respond to a foreign particle by using bone marrow transplants, which are derived stem cells from an adult donor.
According to the article from Aidsmap, Timothy Ray Brown, also known as the “Berlin Patient,” received the transplant in 2007 as part of a lengthy treatment course for leukemia. The case was first reported at the 2008 Conference on Retroviruses and Opportunistic Infections in Boston, and Berlin doctors subsequently published a detailed case history in the New England Journal of Medicine in February 2009. They have now published a follow-up report in the journal Blood, arguing that based on the results of extensive tests, “It is reasonable to conclude that cure of HIV infection has been achieved in this patient.”
The findings of the study summarise what has happened in a nutshell as:
“The man received bone marrow from a donor who had natural resistance to HIV infection; this was due to a genetic profile which led to the CCR5 co-receptor being absent from his cells. The most common variety of HIV uses CCR5 as its ‘docking station’, attaching to it in order to enter and infect CD4 cells, and people with this mutation are almost completely protected against infection.”
The stem cells used are adult as opposed to embryonic cells. This cured patient had leukaemia and received a bone marrow transplant from someone who has natural genetic trait that provides resistance to HIV, this case being occurrent in about 1% of Caucasian people. This might be a very debatable issue as the disease is thought to originate in Africa and yet funny enough the resistant trait is evolved from part of the world less affected by HIV. From the perspective of evolution, resistance develops from an attempt to survive and the new traits would pass on to future generations and be resistant like the case of people with sickle cell anaemia, whose trait evolved from red blood cells that mutated and become resistant to malaria, in part of the world where it is widely prevalent.
As the current approach is very demanding with ablative chemotherapy, immuno-suppressive drugs and stem cell transfer, it is far from the reach of the most needy. This complicated treatment and its associated troubles regarding organ rejection is put in detail in the original article from Aidsmap as:
“The patient continued to receive immunosuppressive treatment to prevent rejection for 38 months, and at 5, 24 and 29 months post-transplant colon biopsies were taken to investigate possible graft-versus-host disease in the intestine. At each investigation additional samples were taken to check for signs of HIV infection in the abundant immune cells of the gut wall.”
The cancer treatment has wiped out his immune system. This is in a nutshell an approach to replenish his immune systems with new functional T-cells but resistant to HIV. This is ridiculously daunting task for both the donor and receiver – this genetic trait is still very rare and will prove very difficult to get bone marrow transplants for every HIV patient from someone who has this genetic trait because there aren’t enough resistant people in the world to give enough bone marrow to cure everyone with HIV unless breakthroughs in gene therapy come to the rescue through cloning these stem cells and using them to a large extent . On top of that, the chances that the body will reject it is fairly high as stated above. The HIV virus is also known for its high mutation rate that it would be hard to rely on using one T-cell receptor. Hence, there is a clinical need to have a vast library of T-cell receptors specific for pieces on HIV, which is a headache for a constantly mutating virus.
With this breakthrough available, medics will not pursue this approach unless it is consolidated by numerous trials and will as well be on clinical trials next year. To start with, the patient could die in due treatment on this approach and to impose such risky treatment when there are well proven anti-retroviral drugs, medicine commonly prescribed for treating HIV, that limit the progress of the viral infection immensely would be a hard call to make.
As can be read from a related article on The Huffington Post, recent studies show that healthy individuals who take anti-retrovirals can reduce their risk of contracting the disease by up to 73 percent. Science has well advanced in an attempt to control the spread of this infectious disease from the development of anti-retroviral drugs, which was the first sign of hope in the epidemic in transforming the disease from a sudden killer to a more manageable illness, to the more contemporary approach to tackle this mounting global problem – using stem cell research. The use of anti-retroviral drugs costs around $13 billion a year in developing countries alone and is expected to triple in 20 years.
These facts summed up imply why controlling it has been a headache for developing nations, whereas the ‘Big Pharma’ has strengthened its muscle through lucrative drug programmes and is hard to see the new research findings infiltrating a well established market soon. To most, they would appeal as a huge prospect but considering one anecdotal evidence as a conclusive scientific evidence to be applied to a viral infection of HIV magnitude on a large scale would be premature. As the above article suggested, while these developments by no means prove a cure for the virus has been found yet they can certainly provide hope for the more than 33 million people living with HIV worldwide.