If you are asked to mention one of the toughest infectious diseases in the world, HIV would be among the list and some people would even conclude that it is the toughest to handle. Since its index case in the 1950s, we have been looking for ways to treat and eradicate this infectious menace but it looks like it is a dog-headed disease and so when people are asked to say something about it, the famous answer is usually it is not treatable but myself and a few set of people will not agree with you because we have had cases of HIV cures at least 7 cured cases till date.
7 cases can be regarded as a victory or a point of concern looking at the number of people suffering from the disease but why have we been able to cure only 7 instead of a large number. Someone might be forced to say that the reason why we have only been able to cure 7 people is as a result of lack of trying but in reality, HIV till date do not have a universal cure, and the 7 patients that have been cured is not a sign of not putting in effort to cure the virus, rather it is about something else that has to do with the tricky virus itself.
Flickr
HIV infects the T-cells of the immune system, and in case you do not know, the T-cells are responsible for fighting infections which means HIV attacks from the root of your defense system. Asides from this, the hard to destroy virus is a Retrovirus which allows it to stick its DNA into the DNA of its host and it lives there and reproduces there without being evicted while preventing your immune system from noticing it. This period is the latent reservoir.
Talking about Latent reservoirs, scientists are looking to work on tackling the virus from this point but it is very difficult as only 1% of the T-cells that are attacked in the body carry a functioning reservoir. This 1% is the reasons a lot of people have to keep using their anti-retro viral medications all their lives because if they stop, the latent reservoirs can wake up and begin to create the virus again thereby increasing the viral load of the virus but some people have been able to stop producing the virus in the body and this is where the 7 people comes in which have been cured of the virus.
These 7 people were treated with a stem cell transplant machine and it was used to treat their blood cancer which is common in people with HIV. So for this people, it was more about treating their cancers and not the virus itself majorly moreover, the treatment method is a last resort for cancer patient because stem cell transplant is risky. In this process, the entire old immune system is removed and a new one is introduced. The stem cells become the immune system and eliminating the entire T-cells in the body of an infected person just theoretically means the reservoir in the body has been eliminated.
Why haven't this been done for everyone with HIV. Remember I said the purpose of doing this procedure was to treat the cancer in the blood and since there are other effective treatment (not cure) for HIV, it will be completely wrong to pick stem cell transplant as the first line of action for treating HIV. Also, considering the procedure for everyone with the virus isn't viable as there are a lot of things to look out for and ensure are in place for it to take place.
First is finding a person with an immune system that is compatible which is very difficult because even family members are guaranteed match, the cell of the donor needs to have two copies of a super-specific gene CCR5 Gene mutation. For the second requirement, only less than 1% of people have two copies of the gene which means it is possible to find a match with the immune system but the person wouldn't have the 2 copies of the gene mutation and vice-versa.
Okay, in the last cured case which was in July 2024 in Berlin, the transferred donor didn't have 2 copied of the CCR5 mutation instead only had one copy. This is a positive move towards curing patients as people with one copy of the mutation are about 16% compared to the about 1%. This could look like a work of wonder but the 6th patient which was the Geneva patient was cured even when his donor didn't have any of the gene mutation.
This looks like a breakthrough, but there have been a lot of people who didn't get results from trying both the 6th and 7th method, so there are still a lot of talk around it and scientists are still tying to understand why the transplant cured the HIV. Some cures even happened without needing to worry about latent reservoirs. Scientists have also turned to CRISPR-Cas9 as a method as you must have heard that it is a gene editing tool which was first detected in bacteria that uses to eliminate viral infection from their cells and rewriting their gene to be safer. Scientists were able to use CRISPR-Cas9 in Lab-specific line of human cells but they were not able to into cells of donors directly.
We can see that it isn't like we are not working hard to ensure that we get result with the cure for HIV, the virus is either just to fast to change and mutate or the method that could help us cure the virus is cumbersome. Other reasons would be not getting the required result in vivo as we got in vitro.
Reference.
https://pmc.ncbi.nlm.nih.gov/articles/PMC9514955/
https://www.mdpi.com/1420-3049/28/1/3
https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0115987
https://retrovirology.biomedcentral.com/articles/10.1186/s12977-021-00581-1
https://pmc.ncbi.nlm.nih.gov/articles/PMC4975809/
https://pmc.ncbi.nlm.nih.gov/articles/PMC5847661/
https://pmc.ncbi.nlm.nih.gov/articles/PMC9863116/
https://www.mdpi.com/1422-0067/24/2/1563
https://www.npr.org/sections/goats-and-soda/2024/07/30
https://www.cancer.org/cancer/risk-prevention/infections
https://pmc.ncbi.nlm.nih.gov/articles/PMC4458206/
https://www.sciencedirect.com/science/article/pii/S2055664020303058
https://www.nature.com/articles/s41590-022-01371-3
