by G Pramod Kumar Mar 5, 2013 08:35 IST
In the last 30 years of the AIDS-epidemic, whenever drugs seemed to have expelled the disease-causing virus from the body of an infected person, it had led to tachycardia of excitement among people living with HIV and the medical community.
Now, an apparent elimination of the virus from a two-and-a-half year old child from Mississippi in the US, born to a mother who is HIV-positive, has raised hopes yet again.
The last time doctors achieved such a 'cure' was three years ago in a person called the 'Berlin patient' who had both an acute form of Leukemia and HIV. Doctors at a Berlin hospital used a radical bone marrow transplantation to cure him of both the cancer and HIV.
In the case of the Mississippi child, the treatment at Johns Hopkins’ Children’s Centre in Baltimore, was not that radical. The child’s mother was HIV-positive, but hadn’t been diagnosed until she went in for labour. Since she was undiagnosed, she also had never taken any AIDS-medication. The instinctive paediatrician, who was in charge of the baby, therefore, felt that the infant was at higher risk of infection and hence started on a high dose of conventional anti-retroviral (ARV) medicines within 30 hours of birth.
By doing so, she had departed from the standard protocol of treatment for the reduction of mother-to-child transmission of the AIDS-causing virus. The standard protocol stipulates that the child born to an HIV-positive mother to be put on one of the two prescribed drugs from childbirth up to six weeks. Instead, the doctor put the child on a regular three-drug cocktail that HIV-positive people take to stay alive.
It was just her scientific instinct that seemed to have worked, because she realised that the child was at higher risk of infection because the mother never took AIDS-drugs. Had the mother been on appropriate AIDS-medication, the quantity of the AIDS-causing virus in her blood could have been negligible, which in turn would have reduced the probability of the child getting infected.
The logic behind the intervention to reduce mother-to-child HIV-transmission is to bring down the mother’s viral load to undetectable levels during pregnancy, reduce the possibility of exposure of the child to the virus during delivery, and early treatment of the child to knock out the virus, if present, from its body.
The Johns Hopkins doctor’s clinical gamble seems to have worked. The child has been followed up and subjected to tests that look for the presence of the virus, not just in the blood, but elsewhere in the body where it could hide. Even after two and a half years, the child seemed be free from the virus.
Now comes the reality check.
Is it just a blip or the real magic bullet?
The 'Berlin patient' reportedly continued to be HIV-free, and two more patients in Boston, who underwent similar bone-marrow therapy, appeared to have been cured of the virus, according to presentations at the 19th International AIDS Congress in Washington DC last year.
While the "Berlin patient’s" success was attributed to the new bone-marrow, which contained a factor that was resistant to the virus, the marrows that the Boston patients received were normal. These cases have led to extensive scientific analysis that opened up the possibilities of normal bone-marrow transplant combined with careful ARV treatment working as a cure.
What the scientists wouldn’t however claim was the absolute certainty of a cure. Whether it is the Berlin patient or the Boston patients, all that they would say was that they had been 'functionally cured' and the virus is invisible.
Will the treacherous virus bounce back from some hidden trenches? They wouldn’t completely rule it out. Even in cutting-edge modern medicine, nothing is absolute and all that one can claim is the highest level of probability.
This is not the first time that the possibility of an AIDS-cure raised unprecedented hopes. When a combination of anti-retroviral drugs (HAART - highly active ARV therapy) had sensationally led to the virus disappearing to undetectable levels in infected people’s blood-streams in the 1990s, the medical world was gripped by the same excitement. However, the virus was hiding in the body’s reservoirs and bounced back.
Dr Antony Fauci of the National Institutes of Health (NIH), one of the greatest contemporary medical scientists and the man who has done pioneering work on these reservoirs and how they posed challenges to a cure when HAART seemed to have been a miracle, was justifiably guarded on the Mississippi child too. "You could call this about as close to a cure, if not a cure, that we've seen," he said.
However, he sounded more optimistic than ever before. In a 2012 interview, he was certainly more guarded. "A cure is still in the very, very formative stages of discovery because we’re not even sure if it’s possible and, if so, how we might go about doing that because of the very special characteristics of this virus."
The doctors at Johns Hopkins use the same term for the treatment of the child, that was used for the Berlin and Boston patients - that the infant has been 'functionally cured'. If HIV-reservoirs continue to be undetectable or absent in the baby, it will certainly be a cure or close to a cure, as Dr Fauci termed it.
Even if it doesn’t turn out to be an absolute cure in the long run, it certainly offers possibilities for pursuing newer methods of AIDS-treatment, both in infants and adults. That the radical application of the drugs seemed to have worked on the immune system of the child, before it was overridden by the virus, shows promise on further reducing mother-to-child transmission. In the case of adults, it opens up new avenues for tinkering with immune responses.
Compared to the first decade of the epidemic, when it meant a miserable and stigmatised death, AIDS today is a chronic, manageable medical condition. People affected with the virus do not like to be called patients, just as they way people with chronic conditions such as diabetes and hypertension detest the term. They also live long, normal and productive lives.
From a handful of drugs with severe side-effects a few times a day to stave off death in the early years, HIV-positive people today need to take just one pill, once a day. A large number of long term survivors of HIV now die of old age and other illnesses than HIV-related complications. The Mississippi child might bring in better news for them.
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