Tracking the New Buzz Around the HIV Cure
On March 3, amfAR, The Foundation for AIDS Research, described the first documented case of a child being cured of HIV. The news shocked the world. Dr. Deborah Persaud of Johns Hopkins University detailed the case of a two-year-old child in Mississippi diagnosed with HIV at birth and immediately put on antiretroviral therapy.
According to amfAR, at 18 months, the child ceased taking antiretrovirals and was lost to follow-up. When brought back into care at 23 months, despite being off treatment for five months, the child was found to have an undetectable viral load. A battery of subsequent highly sensitive tests confirmed the absence of HIV.
"The child’s pediatrician in Mississippi was aware of the work we were doing, and quickly notified our team as soon as this young patient’s case came to her attention," said Dr. Rowena Johnston, amfAR vice president and director of research. "Because the collaboratory was already in place, the researchers were able to mobilize immediately and perform the tests necessary to determine if this was in fact a case of a child being cured."
According to the Associated Press, the HIV treatment was given to the baby before she was confirmed infected with HIV. And Dr. Mark Siedner, a postdoctoral fellow in the division of infectious diseases at Massachusetts General Hospital and Harvard Medical School, said the question still remains as to whether the child was infected with HIV upon birth, or merely exposed.
"In the case of the Mississippi baby, we know she was exposed to HIV, had HIV in her blood, and that at least some cells in her blood were found with sleeping virus -- though we will likely never know if those cells were from the child or maternal cells that had been transmitted during pregnancy or birth," Dr. Siedner wrote in an opinion piece in the Wall Street Journal. "Was the baby infected with HIV and, thus, cured? It seems more likely that her treatment prevented her, after exposure to HIV, from being infected."
But Dr. Persaud argued that comprehensive tests have confirmed beyond doubt that both mother and child were HIV-positive when the child was born, and today no signs of HIV infection in the child can be detected by the most sensitive means available.
"Given that this cure appears to have been achieved by antiretroviral therapy alone," said Dr. Johnston, "it is also imperative that we learn more about a newborn’s immune system, how it differs from an adult’s, and what factors made it possible for the child to be cured."
The Mississippi case is important for two reasons. On one hand, it underscores the importance of identifying HIV-positive pregnant women, expanding access to treatment regimens that can prevent mother-to-child transmission, and of immediately putting infants on antiretroviral therapy in the event that they are born HIV positive. On the other hand, it points to the possibility that different populations of HIV-positive people might be cured in different ways.
The First Cure: Timothy Ray Brown, The Berlin Patient
Outside of the Mississippi case, the only other documented case of an HIV cure to date remains that of Timothy Ray Brown, the so-called "Berlin patient."
In 2006, while on treatment for HIV, Brown was diagnosed with leukemia. His physician was able to treat his leukemia with a stem-cell transplant from a person who was born with a genetic mutation causing immunity to HIV infection. Following the transplant, Brown was able to stop HIV treatment without experiencing a return of his HIV disease.
Many hailed Brown as a "medical miracle." But others asked the question, "How else can HIV be cured?"
Scientists are making progress on several fronts in the search for a cure for HIV infections. Promising tactics range from flushing hidden HIV from cells to changing out a person’s own immune system cells, making them resistant to HIV and then putting them back into the patient’s body.
A major stumbling block is the fact that HIV lies low in pools or reservoirs of latent infection that even powerful drugs cannot reach, scientists told the Conference on Retroviruses and Opportunistic Infections in Seattle, Washington. The conference is one of the world’s largest scientific meetings on HIV/AIDS.
Still, scientists report that advances in molecular engineering are allowing researchers to delve more deeply into the mechanism of HIV.
Bee Venom Application Can Kill HIV
Nanoparticles carrying a toxin found in bee venom can destroy HIV while leaving surrounding cells unharmed, said scientists at the Washington University School of Medicine in St. Louis.
The study, published in the current issue of the journal Antiviral Therapy, suggests that the bee venom can be loaded onto nanoparticles that are then suspended in a gel and applied topically to prevent HIV infection.
"Our hope is that in places where HIV is running rampant, people could use this gel as a preventive measure to stop the initial infection," said Dr. Joshua L. Hood, one of the researchers.
Bee venom contains a potent toxin called melittin that can poke holes in the protective envelope that surrounds HIV and other viruses. That toxin might also harm normal cells, but Hood added what are described as ’protective bumpers’ to the nanoparticle surface.
When the nanoparticles come into contact with normal cells, which are much larger in size than viruses, the particles simply bounce off. HIV, on the other hand, is even smaller than the nanoparticle, so HIV fits between the bumpers and makes contact with the surface of the nanoparticle, where the bee toxin awaits.
"Melittin on the nanoparticles fuses with the viral envelope," Hood explained. "The melittin forms little pore-like attack complexes and ruptures the envelope, stripping it off the virus."
According to Hood, the advantage of this approach is that the nanoparticle attacks an essential part of the virus’ structure. In contrast, most anti-HIV drugs inhibit the virus’ ability to replicate, but this anti-replication strategy does nothing to stop initial infection, and some strains of the virus have adapted to common drugs and reproduce anyway.
"We are attacking an inherent physical property of HIV," Hood said. "Theoretically, there isn’t any way for the virus to adapt to that. The virus has to have a protective coat, a double-layered membrane that covers the virus."
Melittin could also be used as therapy for existing HIV infections, especially those that are drug-resistant. The nanoparticles could be injected intravenously and, in theory, would be able to clear HIV from the blood stream.
"The basic particle that we are using in these experiments was developed many years ago as an artificial blood product," Hood said. "It didn’t work very well for delivering oxygen, but it circulates safely in the body and gives us a nice platform that we can adapt to fight different kinds of infections."
Since melittin attacks viral membranes indiscriminately, this concept is not limited to HIV. Many viruses, including hepatitis B and C, rely on the same kind of protective envelope and presumably would be vulnerable to melittin-loaded nanoparticles.
Hood added that the nanoparticles are easy to manufacture in large enough quantities to supply them for future clinical trials.
Study Finds 14 Adults ’Functionally Cured’ Of HIV
According to a new study in the journal PLOS Pathogens, 14 adults have also been "functionally cured" after they were given combination antiretroviral therapy (cART) for their HIV infection.
In all 14 cases, the subjects have been able to stop taking the treatment while still keeping their infection under control.
The 14 adults still technically have HIV in their bodies, but it’s only barely detectable when using highly sensitive laboratory methods. Therefore, they are considered "functionally cured" instead of being completely rid of the virus.
Still, the results show that early and prolonged cART may allow some individuals to achieve long-term infection control and may have important implications in the search for a functional HIV cure.
According to the authors, 70 people participated in the study and had been treated early for their HIV infection (between 5 and 10 weeks of being infected).
Most of the 70 people relapsed when their treatment was interrupted, with the virus rebounding rapidly to pre-treatment levels, reported The New Scientist, a weekly science and technology news magazine. But 14 of them -- four women and 10 men -- were able to stay off ARVs without relapsing, having taken the drugs for an average of three years.
"The findings suggest that anywhere from 5 to 15 percent of people are able to be ’functionally cured’ of HIV," the study researcher, Dr. Asier Saez-Cirion, told BBC News.
"They still have HIV, it is not eradication of HIV, it is a kind of remission of the infection," Saez-Cirion told BBC News.
A person with HIV must take antiretroviral drugs every day for the rest of his or her life, according to AVERT.