Controversial trials of a treatment that could help Aids sufferers unable to afford drugs are being held up by arguments over the science and ethics. Steve Farrar and Karen MacGregor, in South Africa, report.
Thembe Dlamini's brown eyes mist over as she recounts how two years ago she learned that she had HIV and was doomed to die: "I was often feeling hungry and tired, and I was losing weight. My best friend urged me to take an HIV test. It came back positive. I was terrified - still am. I've been told to eat lots of fruit but I am getting sicker and what I want is medicine."
The 35-year-old dock worker at Durban's bustling port earns just Rs1,100 (£100) a month on which she and her teenage daughter barely survive. There is no way she can afford the drugs commonly prescribed in the West, and she will not get them from the government.
Thembe (not her real name) is too terrified to tell her family that she has HIV. People have been killed in Durban for admitting infection. Her fingers pluck anxiously at her blue overalls as she makes me promise, again and again, not to use her real name. "Only my friend knows. She also has HIV and her husband has already died of it. I'm scared for my daughter. What are we to do?" At the University of Natal in Durban, Alan Smith, professor of virology, shares Thembe's despair. As a medical scientist, acknowledged as one of South Africa's leading virologists specialising in HIV/Aids, he is deeply frustrated at his inability to help. The scale of the epidemic is staggering. On the docks where Thembe works, Smith calculates that some 800 of the 5,500 workforce are infected. Four million South Africans are HIV-positive, while sub-Saharan Africa accounts for 70 per cent of the world's 36 million infected.
Most western sufferers receive anti-retroviral and protease-inhibiting drugs to prolong their lives. The Department of Health estimates 14,000 of the 22,000 HIV-positive people in the United Kingdom were treated in this way in 1999. Combivin, GlaxoSmithKline's best-selling Aids therapy, costs $17 (£12) a day in the United States. The not-for-profit charge of $2 a day for designated "least developing countries" still works out at $600-$700 a year, far beyond the means of most.
"There is no way Africa can afford anti-retrovirals for all but a privileged few, so we have to find other ways of extending infected people's lives and improving their quality of life," Smith says. And he believes the answer may already be here - passive immune therapy.
PIT is the brainchild of Abraham Karpas, a researcher at Cambridge University's department of haematology. Karpas, the first British scientist to isolate HIV and the creator of the first human hybridoma cell that could produce monoclonal antibodies, has pursued the idea since the mid-1980s.
The principle is simple. The blood of relatively healthy HIV-positive individuals should be full of natural antibodies created by the body to fight the infection. But over the course of the disease, the level of antibodies declines. Karpas reasoned that if serum from healthy patients - heat-treated to inactivate the virus - could be transfused into patients whose disease had progressed much further, it might effectively boost the recipient's natural defences, buying them more time.
Mainstream science is indifferent, however. Many have serious misgivings about the science behind PIT and fear it could raise false hopes amid the desperation of the developing world. Some believe its apparent effects may not be as a result of antibodies as Karpas believes and question its efficacy. Others feel the technique might be useful only if purified HIV antibodies are administered. Few have chosen to follow Karpas's lead.
One leading British expert, who declined to be identified, wonders about the ethics of trialling a therapy in the developing world that is less effective than drugs available in the West. "I worry that the people in the developing world will get drawn into something which is quasi-medical, taking money and effort away from other things. It would be better to encourage them to make generic drugs and ignore the patent rulings," she says.
PIT has, in fact, undergone a few experiments and small-scale trials. Most significantly, a trial involving 86 French Aids patients was published in the US in the Proceedings of the National Academy of Sciences , one of the world's top scientific journals, in 1995. Over 12 months, 18 of those given the therapy died or developed new opportunistic infections compared with 29 who received a placebo.
Jean Jacques Lefrere, one of the researchers and head of blood-born transmissible agents at the National Institute of Blood Transfusion in Paris, says the results were interesting and showed an absence of side effects - but paled compared with the drug therapy that emerged the following year.
He feels that an African trial is a reasonable proposal, though he doubts that Africa's health infrastructure could organise the safe collection, treatment and transfusion of large quantities of HIV-positive plasma. "Theoretically, PIT could be an alternative to drugs in developing countries, but I'm very doubtful about the practicality," he says.
Gary Blick, a medical practitioner and Aids specialist from Stamford, Connecticut, who has treated patients with monthly PIT since 1992 and whose humanitarian group Global Health Organisation is to embark on work in Botswana, also wants a trial. "PIT needs good research to either put it to rest or prove it," he says.
Smith is unimpressed by the critics. He says: "My feeling is PIT has a great deal of potential and is certainly worth a trial in a desperate country like South Africa."
Furthermore, if proved effective, he believes PIT would be affordable and could take advantage of the country's established urban health infrastructure. Smith wants to work with Karpas on a trial involving some 120 HIV-positive workers carried out at a Durban city-centre hospital recently taken over by his university. He says there is a ready supply of HIV-positive blood, currently destroyed after its inadvertent collection at transfusion centres. All he needs is money and subsequent approval by his medical school's ethics committee.
Three years ago, Karpas was granted £150,000 by Trinity College's Isaac Newton Trust for an African trial. Previously, his application for funding from the Medical Research Council had been turned down. However, Sir Keith Peters, regius professor of physic and head of Cambridge University's clinical school, blocked the transfer of the trust's grant - which was to involve a number of East African scientists - as he was concerned about issues of clinical responsibility and ethical approval.
John Rallison, director of the trust, said the clinical school's backing was vital, especially as ethical concerns surrounding the proposed trial had been raised by trustees.
Karpas has a turbulent relationship with Sir Keith, whom Karpas sees as stifling his research. "The evidence so far is that PIT does work and it could prolong the lives of millions of people, though it is not going to cure them. I was very surprised and disappointed that my money to start a study in Africa was blocked," Karpas says.
Sir Keith flatly denies he has acted out of anything other than fair and professional judgement. Nevertheless, when he received a letter from Smith asking him to release the money for the South African trial, he did not reply. He said: "I saw that letter quite simply as an attempt by Dr Karpas to stir the beef again."