I read with fascination this NewScientist (29 February 2020, paywall) article on how we potentially carry the seeds of our self-destruction … in our own DNA:
STRANGE fevers and unusual infections are common among the people with HIV who come to Avindra Nath’s clinic for treatment. But when one young man showed up in 2005 struggling to move his arms and legs, Nath was baffled. Although the man had been diagnosed with HIV a few years earlier, his new symptoms matched those of amyotrophic lateral sclerosis (ALS), also known as motor neuron disease. In an attempt to get his HIV under control, Nath convinced him to start taking antiretroviral drugs. Much to everyone’s surprise, his ALS symptoms improved too.
ALS is caused by progressive deterioration and death of the nerve cells that control voluntary movement. What triggers this destruction is unclear, but recovery is rare. Puzzled, Nath, who ran an immunology clinic at Johns Hopkins University in Baltimore, began searching the medical literature. There he found other people with HIV and ALS whose ALS symptoms improved with antiretrovirals – drugs that stop viruses replicating. Could this neurological condition be triggered by a dormant virus hiding in our DNA, brought back to life by HIV?
This question doesn’t only hover over ALS. Increasingly, we are waking up to the possibility that conditions including multiple sclerosis (MS), schizophrenia and even type 1 diabetes may in some cases be triggered by ancient viruses buried in our genomes. Under certain circumstances, they revive and start producing mutated versions of themselves, triggering the immune system to attack and destroy neighbouring tissues.
If retrovirus is a new term for you – it was for me – here it is:
A retrovirus is a type of RNA virus that inserts a copy of its genome into the DNA of a host cell that it invades, thus changing the genome of that cell.
Once inside the host cell’s cytoplasm, the virus uses its own reverse transcriptase enzyme to produce DNA from its RNA genome, the reverse of the usual pattern, thus retro (backwards). The new DNA is then incorporated into the host cell genome by an integrase enzyme, at which point the retroviral DNA is referred to as a provirus. The host cell then treats the viral DNA as part of its own genome, transcribing and translating the viral genes along with the cell’s own genes, producing the proteins required to assemble new copies of the virus. It is difficult to detect the virus until it has infected the host. At that point, the infection will persist indefinitely. [Wikipedia]
And then the NewScientist article suggests that something activates the viral DNA, which then stimulates and maybe overstimulates the immune system into attacking the host’s body.
As someone with a controlled case of gout, which is an auto-immune disorder, I’m more than a little fascinated with this. Could I be infected with a retroviral which has disabled the body’s equipment for making the enzyme which I lack, which is responsible for dissolving the uric acid crystals which occasionally form in my toe joints, and potentially elsewhere?
I hope I find out, even if no cure is found. Just the idea that a virus can get into my DNA is totally weird.
