Hunting for a "cure" for HIV

A successful microbicide trial and the promise of HIV treatment as prevention have dominated the scientific breakthroughs making headlines at the International AIDS Conference in Vienna, but scientists working on a cure for HIV say they are making slow but significant headway in finding a permanent solution to the epidemic.



The main focus of current research is how to find and tackle "reservoirs" – cells, organs or tissue in the body where the virus could remain latent - and eventually become active again.



"Cells harbour HIV for long periods of time, and there are so many different types of cells that move all over the body; these reservoirs can be located anywhere these cells can reach," said Maureen Goodenow, a professor of pathology at the University of Florida.



Current research is seeking a "functional cure", which would not eliminate the virus from the body but would allow a patient's immune system to control the virus without the need for lifelong medicine by using antiretroviral (ARV) drugs and medications for a limited period to target these reservoirs. At least two clinical trials are underway in France to test such products.



"[HIV] treatment can reduce the viral load in the blood but it cannot eliminate it; it's life-long and can have many side effects after long-term use," said Prof Francoise Barré-Sinoussi, who earned a Nobel Laureate in Medicine for her role in the discovery of HIV.



"We are trying to find a treatment that is more efficient, causes fewer complications, and can be stopped after a while; one that would improve a patient's quality of life," she told IRIN/PlusNews.



Stem cell research



In terms of funding, the search for a cure is the poor relation to HIV prevention research. Scepticism about the possibility of finding a cure for such a complex virus, and a lack of significant strides in the field over the last 30 years, have made donors reluctant to support this arm of research.



In 2009 the National Institute of Allergy and Infectious Diseases (NIAID) at the United States National Institutes of Health (NIH), one of the largest donors to global HIV research, spent just over US$40 million - about three percent of its total AIDS spending - on the search for a cure.



"For many years there was a staleness in the field, but now there are a number of breakthroughs, including stem-cell technology, that make it feasible to address the issue," said Carl Dieffenbach, director of the AIDS division at NIAID. "The NIH now plans to ramp up its efforts to find a cure."



The excitement over stem-cell research was caused by a case known as "the Berlin patient". In 2007 Dr Gero Hütter, the doctor treating the Berlin patient – an HIV-positive American leukaemia patient who lived in Berlin - replaced the patient's bone marrow cells with those from a donor with a naturally occurring genetic mutation that rendered his cells immune to HIV.



To date the Berlin patient, who is no longer on ARVs, shows no evidence of having the HI virus.



Researchers in the US are using the same genetic mutation to do stem-cell research in mice in the hope that, eventually, it could provide immunity to HIV-infected patients. Recent positive results have increased interest in this line of research.



Back to basics



But scientists believe that they also need to do more fundamental research into exactly how the virus works. "There is a dearth of information on the basic immunological system, on the molecular interaction between the virus and cells," Goodenow said.



Dieffenbach noted that Hütter, the Berlin patient's doctor, was a haematologist and not an HIV specialist, and said there was a need to collaborate more closely with scientists from diverse fields, from immunologists and virologists to basic scientists and drug developers.



Jean-Francois Delfraissy, director of France's National Agency for AIDS Research, commented: "The real cure – the total eradication of HIV from the body – is a very big task, but we are hopeful that we are taking baby steps towards controlling the virus in infected patients."



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