What happens to HIV once it completely destroys the immune system?

Question

Today, in my high school health class we were learning about HIV and AIDS, and I was wondering what would happen to HIV if it killed off all of the cells that it uses to reproduce.

For example, imagine this hypothetical scenario: A patient with HIV goes to a doctor who puts them in a sterile environment and gives them every medicine necessary to protect them from other diseases that might be lurking in their body (to protect them from common illnesses that could become deadly without an immune system, like the common cold). While they are in this sterile environment, they allow the HIV virus to attack all of the immune system cells, until eventually they are all destroyed.

So my question is: If all the immune system cells are dead and the virus can't take them over, would the virus just "die" out, effectively curing the patient?

Answer 1

This is a very interesting question. It's also highly speculative, and vague (what does "a doctor... gives them any medicine necessary to protect them from other diseases that might be lurking in their body" mean? Does it mean they treat the symptoms of AIDS (weight loss, diarrhea, etc?) If it does, then the difference between not treating HIV but treating every complication stretches this almost to the point of meaninglessness. If you are postulating treating all diseases, then I do believe this is speculative at best and unanswerable.

The most likely scenario is that the patient would eventually die (but don't we all?) How he would die is pure speculation.

Unfortunately, while you can place a patient in a sterile environment,

1. you can't sterilize a patient

2. it's exceedingly difficult to sterilize food

3. to prevent all possible hospital acquired bacterial infections, they would need a bubble-boy-like unit (very rare and extremely expensive)

4. you can't predict if some previously unknown virus dormant in our bodies will be able to express itself. (See @Fomite's comment.)

The fact that you stipulate treatment for everything but the virus that replicates in certain blood cells associated with immunity is almost an aside if you're going to treat all pathogens.

Every bacteria and virus he has in his body will go into that sterile environment with him, so it depends what he has going in. When he no longer has enough immune competency to keep these under control, they will take their toll. If you treat him in a sterile environment and give him world-class treatment of all infections (anti-virals would be needed to treat herpesvirus recurrences, like chicken pox and HSV1, HCV, HepBV, or any other number of viruses one can carry, treat the encephalitis that comes with HSV/etc. He has a small chance of possibly outliving the disease, only to die in the 3-5 days after you turn him out, unless you include bone marrow transplant in the treatment as well.

The progress of HIV to AIDS is variable. Less than 0.5% of patients never develop any sign whatsoever of the infection except for undeniably positive titers. What if your patient is in this small but not-nonexistent subtype? Then there are almost everything in between, with fewer patients on the healthy end than the sick end.

My best guess: your patient will die of some ultimately unconquerable disease you are treating in the bubble, for example, multi-drug resistant C. diff, Kaposi's sarcoma, Mycobacterium avium-intracellulare, Toxoplasmosis (Up to 50% of the world's human population is estimated to carry Toxoplasma) liver failure from rampant Epstein-Barr, or some other opportunistic infection from something he carried in there but is either devastating or drug resistant.

You're asking if the virus will just "die" out, effectively curing the patient. That's kind of like letting the heart and lungs die, but keeping the patient alive on a heart-lung bypass machine. That's not a cure, and upon turning it off, the patient will die.

And that's purely a guess, which, on SE, makes it worthless.

_{Long-term Nonprogressive Disease Among Untreated HIV-Infected Individuals: Clinical Implications of Understanding Immune Control of HIV}

Answer 2

In addition to what anongoodnurse wrote about the patient likely dieing, I don't think this scenario would work at all.

HIV doesn't infect all immune cells. It infects T-cells/CD4 cells, which are used for adaptive immunity. There are two features of HIV infections that make your scenario impossible or almost impossible:

1. The time between infection of a cell and lysis (death) can be long, and it can even stay dormant. So there can always be cells that are infected and it can take years before the virus emerges from them
2. In the meantime, new T-cells are produced by the body, even in patients with HIV, though very slowly. The bone marrow that produces them is still there.

In some people with AIDS, the number of CD4 cells counted in blood samples actually goes down to 0, which would be as close to your scenario as people can get and it still doesn't make them cured. The "viral load" measured in these patients is usually very high. Remember that HIV needs human cells to reproduce, not to survive. It will happily exist in an individual with no CD4 cells. That person can infect others and because the immune system can't replenish the CD4 cells fast enough (and they get infected soon after being produced) the immune system just stays very, very weak.

The stem cell therapy approach to HIV was mentioned in comments, so I'd like to address that. It's not as "easy" as just doing a bone marrow transplant. The new cells would just get infected. The donor has to be immune to HIV (some people are due to a mutation), so the newly produced cells can't be infected by the virus. Unfortunately, the mutation is rare.