To a society that managed to eradicate smallpox (thanks to Edward Jenner) and develop vaccines for various other infectious diseases, it seems quite unthinkable after 20 years of intense research and surely many billions of dollars spent that we do not yet have a cure for HIV/AIDS. Yes, I know that the disease is much more manageable today, and combinatorial therapy with antiretroviral drugs has been very effective in prolonging the life of patients. While diagnosis was a death sentence in say, 1990, today a young HIV-positive person detected early on can expect to live for 50 years more, if treated. This is of course wonderful news, but it remains extremely frustrating that the best and brightest scientific minds of the twentieth century could not defeat this little packet of single-stranded RNA that encodes a mere nine genes, in comparison with hundreds of genes in bacteria or tens of thousands of genes in humans. Nine genes, with the potential to wipe out the human race if allowed to spread? It truly is a shocking thought, and an eternally fascinating challenge to a scientist. With the huge amounts of money that were being poured in, it seemed certain that we would have had a vaccine by the year 2000, if not before. Sadly, that didn't happen, and no true cure has yet been found.
It is with this on my mind that I read with incredulity that we now have the first person in the world who has been cured of AIDS, and I don't mean "cured": I mean cured! Timothy Brown, 46, is the first and only human who has been quite literally cured of the disease, and that news stunned me. I just had to read on to find out what made him so unique, and made such a cure even remotely possible. It turns out that as part and parcel of treating Brown for leukemia, he was given a transplant of blood stem cells that came from a donor that unbelievably had a genetic mutation that made them resistant to HIV infection. I don't know whether this was known at the time, but if not, it's not just an incredible stroke of luck: it was divine intervention! Less than one percent of Caucasians have that genetic mutation, so finding a donor who is both transplant-compatible and who also carries the resistance is not going to be a simple affair. The process is complicated by adult donors, because in this case the match between donor and recipient needs to be extremely good, whereas with umbilical cord blood, one has more room to move. So it seems that umbilical cord blood transplants may well be the way forward, even if in the testing done thus far, out of some 17,000 cord blood samples, only 102 carried the gene for resistance. That comes about to be just over half a percent, but we cannot get bogged down by percentages here, and should rather focus on the the number 102. If that means another 102 people can be similarly cured, for good, then that sounds like an amazing place to start. Timothy Brown had his transplant in 2007, and today is considered to be totally free of the virus and officially cured of HIV/AIDS. A staggeging outcome!
But the struggle goes on to get inside the "head" of this rapidly evolving retrovirus, and to come up with the magic bullet that wipes it out, for everyone's sake. One cannot help but feel that the situation is a perfect example of "big is not always better", given that its nine genes can outwit, outlast and outplay our thirty thousand or so. If life is only about getting enough to eat and propagation of that life, well, until today at least, this tiny little RNA package has us by the short and curlies. It represents a very complex simplicity, or a frustratingly simple complexity, or both. But in either case it remains an enormous intellectual, scientific, economic and global challenge, and one that just has to be hurdled hopefully sooner rather than later. - Kevin Mc
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