April 21, 2014

Progress in Kenyan doctor’s quest for elusive HIV cure

CELL
button print grnw20 Progress in Kenyan doctor’s quest for elusive HIV cure

The ‘Berlin Patient’, the first man on record to be cured of HIV, has inspired a flurry of medical trials across the world with researchers believing the therapy can be replicated or modi?ed to treat other patients.

A local researcher, Dr Simon Barasa Situma of the Kenya Polytechnic University College, has been involved in one of the studies at the University of North Carolina in the US involving 16 Kenyan patients.

In this study, ?rst published last July in the journal Nature, it emerged that researchers administered a cancer drug called Vorinostat to eight HIV positive men who were on ARVs hoping to lure the virus out of its hiding places.

Within days of the treatment, the patients’ viral load had shot up dramatically, indicating the virus had been successfully lured out of the hideouts and was now exposed to both the ARVs and the immune system.

The patients are still being monitored. The existence of hiding places in the body for viruses that are not attacked by antiviral drugs is believed to be a major reason why infection re-emerges once patients stop taking their medication.

“This work provides compelling evidence for a new strategy to directly attack and eradicate latent HIV infection,” Dr David Margolis, the study leader, had told the journal.

During the 2012 Aids Conference in Washington DC, researchers at the Brigham and Women’s Hospital in Boston reported that they had performed bone marrow transplants on two HIV positive men and this had cleared their system of the HIV-causing virus.

“We expected HIV to vanish from the patients’ plasma, but it is surprising that we can’t find any traces of HIV in their cells,” Dr Timothy Henrich, one of the researchers, told the conference.

Further studies are still being carried out on these men to decide whether they have been cured of HIV, and if so, the scientists want to under-stand how this happened.

Addressing the conference, the researchers said having not races of HIV in their white blood cells was an indication that the hiding places or reservoir may have been eliminated.

The differences between the Berlin man, the 16 Kenyans being treated by Dr Barasa and the two Boston men, is that the pair were still on antiretrovirals by the time the study was being reported in July.

Separately, scientists are trying to use gene therapy to alter patients’ immune systems to free them of HIV. Scientists at the Fred Hutchin-son Cancer Research Centre in the US are trying to perform stem cell transplants with cells that have been genetically modified to be resistant to HIV, much like the cells that the Berlin patient received.

The Berlin Patient was treated in 2007 and so far he has not been on antiretrovirals, but nobody knows exactly how the virus was eliminated.

Several theories have been advanced indicating three possibilities. First, chemo therapy for cancer killed off most of the cells infected with HIV.

By itself, medical experts’ have argued, this would not be enough to cure HIV. Second, the donor cells repopulated the patient’s immune system. The new cells attacked and killed the patient’s remaining white blood cells.

This process is thought to have killed of many of the remaining cells carrying HIV.

Third, the donor cells were resistant to HIV infection. As HIV emerged from resting cells, the virus helped kill off the old cells.

When the new donor cells expanded to take their place, the HIV had no place to go and withered.-The Standard

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