Image copyright AFP Image caption Hectares of surrounding acreage was kept in quarantine for several weeks
A second HIV patient may have been cured of infection without an operation to extract stem cells from their bone marrow, according to Japanese researchers.
In 2010, it was reported that another patient had tested free of HIV.
This was attributed to a treatment which used a patient’s own cells to multiply to build a normal immune system.
Now, Japanese researchers say a second patient may have been cured, having learned how to “degrade” a new virus before it emerged.
This breakthrough is said to have been made possible by using a new technology called RNA interference (RNAi).
(Please note: This story contains images of cells with HIV)
Image copyright Reuters Image caption The patient was administered genetic material to suppress the virus before treatment
Earlier this year, US scientists reported two cases in which apparently identical patients both cured themselves of the HIV infection by injecting themselves with stem cells from donor.
In the case of the two patients known as the “Gene Therapy Two” the treatment involved putting the patient’s own stem cells back into the body – a procedure known as “regenerative cell therapy”.
Dr Mika Sugisaki of the Saitama Medical Center, in Saitama, Japan, told a meeting of the European Society of Cell Biology in Amsterdam last week that a second case had been reported there.
He and a team of researchers were attempting to diagnose and treat the disease that is known as pre-leukopenia, an incurable condition of anaemia and chronic low platelet levels in patients with AIDS.
Pre-leukopenia has a lower threshold for infection with HIV and leaves patients susceptible to the opportunistic infection of the stomach and liver which make people ill and have a limited life expectancy.
All individuals with pre-leukopenia are high-risk to HIV and might be susceptible to other opportunistic infections such as hepatitis B.
In order to make a patient resistant to these infections, which are treatable through anti-viral therapy, the team hoped they could assess the hepatitis B level in their liver before injecting stem cells.
Image copyright Getty Images Image caption The virus, known as Haemophilia-1, is passed between family members
To do this, the team injected into a single patient 22 sections of a viral genome, which they then simulated over and over until they “degraded” the virus.
The reaction would, they reasoned, make the virus unable to circulate to establish a new infection.
Both patients were so severely anaemic, they were already at much greater risk of death and therefore had a limited life expectancy and should be treated as organ donors, they thought.
But this second treatment – a genomic trait modification known as RNAi, used nucleoside reverse transcriptase (NRTT) protein which their immune system found easy to copy.
These viruses were then analysed, and found that several spots had changed.
In one spot, a Hemophilia-1 strand of RNA – which is passed between blood relatives – was now incompletely rendered, making the virus unable to infect the liver.
When they examined the other spots, in the liver of the infected patient, the team found that a different cancer-killing T cell present in a healthy patient also infected the virus.
The immune system from the two patients were so different, they said, that only the difference in the functioning of the cells in the immune system would be a factor.
Professor Phillip Fawcett, of the British AIDS Society, told BBC News: “Transcriptase editing seems to be an important mechanism for this sort of treatment.”
However, he added that if the treatment was produced in batches and were to become widely available, it could present challenges.
First, he said it was unclear whether the cells would be able to be replanted and then accumulated properly in the bone marrow for the treatment to work.
Second, one worry was that the drugs needed to suppress the virus would have to be taken for life, which would potentially be more onerous than patients would have to take.
A new technology called RNAi can, the researchers believe, help deal with these problems and make them safer.
More than 400,000 people are currently living with HIV in Japan – nearly three times the country’s population.