Cure: Immune System
After analyzing of 1.5 billion cells from this person considered to be rare, no trace of the virus was found.
It was believed some rare people may be able to cure themselves of viruses.
Previously to fight HIV, there was a need for external help where the technique of bone marrow transplant was used to drop the different levels of HIV in their body to undetectable levels. But now it appears that functional HIV may have been fought with no external help after the reports of this rare person.
What Happened inside his body?
Researchers report August 26 in Nature, analysis of more than 1.5 billion cells taken from a patient known as EC2 showed no functional HIV copies in any of them. Still, some nonfunctional copies of the virus were found in the person. The finding suggests that some people’s immune systems can get the upper hand, while no one can say for sure that an intact virus isn’t hiding in a cell somewhere in this person’s body, essentially eliminating the pernicious and persistent virus.
Another person known as EC1 in 1 billion blood cells analyzed had only one functional copy of HIV. The one functional copy found in the body was in resemblance to a supermax prison in genetic terms. This genetic lockup can be considered as the key to being able to naturally control the virus.
An elite controller is a rare group of peoples, can maintain very low or undetectable levels of HIV without antiretroviral drugs and these two persons belong to this group. No such symptoms and clear signs of damage by viruses are found by these people. Satya Dandekar, an HIV researcher at the University of California, Davis School of Medicine who was not involved in the study said that it is not an analysis of a few months or years but it is for a very long time. In 99.5 % cases to keep the virus in control, drugs are the only way i.e. the world’s more than 35 million people infected with the virus will need drugs.
How Elite Controllers do it?
Researchers have the curiosity to know how elite controllers fight the virus for long periods. Dandekar says, it has been difficult to figure it out because no one has recorded the first fight scenes between HIV and the elite controller’s immune systems. As researchers miss the initial knockouts the immune system has thrown at the virus in long run. And by the time an elite controller is recognized, the fight is already won.
Joseph Wong, a virologist at the University of California, San Francisco, says about a quarter of elite controllers have genetic variants in key immune system genes that may help them get a handle on the virus. He also says that it explains what’s going on in only a minority of elite controllers, and isn’t something not beneficial for others and not easily transferred to others.
Dandekar says it may be possible that only “wimpy” versions of HIV were present in the elite controllers. So the researchers examined the HIV viruses embedded in DNA from 41 HIV-infected people taking antiretroviral drugs and 64 elite controllers. Undetectable levels of virus were maintained by the elite controllers without drugs from 1 to 24 years (EC2 case).
How HIV makes its presence?
HIV is a retrovirus, meaning genetic information of HIV is stored in RNA. An enzyme called reverse transcriptase inserts into DNA by copying that RNA, which can then insert into the host’s DNA. But also it results in defective or incomplete copies of the virus as reverse transcriptase is error-prone. So this may be possible that the elite controllers might be loaded with these nonfunctional versions, according to the researchers. Xu Yu, an immunologist at the Ragon Institute of MGH, MIT, and Harvard in Boston says this can’t make the infectious virus.
But this also not the possibility in the elite controllers. Surprisingly, most elite controllers in the study are more prone or exposed to the intact virus than expected. Xo Yu and colleagues studied further to see where the virus had landed in patients’ DNA.
Monica Roth, a virologist at Rutgers University Robert Wood Johnson Medical School in Piscataway, N.J says in most people infected with HIV, the virus lands near or in genes, thanks to some human proteins that shepherd it there. But the virus was trapped in gene-poor parts of the human genetic instruction book or genome in these elite controllers. When it did land in or near genes, it prevented the genes from being turned on as they were ones that are wrapped in the molecular equivalent of razor wire. Heterochromatin is collectively those inactive, tightly guarded parts of the genome.
Roth, Yu’s Ragon Institute colleague, who was not involved in the work says plunking HIV in heterochromatin is like putting it in the trunk and then locking the trunk. Although, they would mostly be inert as those silenced copies of HIV might briefly stir and produce infectious virus.
But still, researchers were interested in finding out whether elite controllers have a propensity for steering the virus to heterochromatin. Just like what happens in the cells of other people, the guide proteins in elite controllers’ cells still direct HIV insertions in or near genes.
What so Special in Elite Controllers?
Mathias Lichterfeld, a virologist and infectious diseases physician says that it’s probably not that elite controllers just got lucky at the beginning of the infection to get HIV trapped in heterochromatin. Instead, the researchers think elite controllers’ immune systems left behind only broken copies of the virus and intact versions locked in heterochromatin and eliminated cells producing functional virus.
This study may hold hope for others infected with HIV, but still, they are more researches to be carried out.
Roth says, once they figure out the mechanism by which this is working, maybe they can figure what goes wrong in everyone else and fix it. The researchers may have narrowed their path by eliminating some possibilities, but haven’t solved the mystery yet of how elite controllers achieve their status. He says this paper out is just a cliffhanger as the questions persist how is this done?