If I’m reading this correctly it sounds like it might a kind of beneficial graft-vs-host reaction?
The HIV-free transplanted immune system sees the original immune system as alien, and proceeds to wipe it out at the cellular level. This presumably takes the HIV with it, even if the new immune system is not itself resistant.
I guess this means that quiescent HIV is not at a stage in its lifecycle where it can reinfect cells if its host cell is destroyed. My hilarious mental model of infectious HIV virions floating inside a CD4+ T-cell like angry bees inside a balloon is clearly mistaken.
I vaguely recall there was a case a few years back where a patient had been cured of HIV. But they had effectively their entire immune system wiped out by radiation therapy or something along those lines, and then received a bone marrow transplant from a healthy donor. So not something that could easily be replicated in many patients.
Still, that is big news, considering how many people have died from HIV, and how many still live with the virus. Treatment has come a long way - I remember how it was practically a death penalty in the 1990s; but a complete cure would be so much better than depending on medication for the rest of one's life. I don't think this is the breakthrough, but it is proof that search for a cure is not futile.
People have to understand that individual cases of effectively curing HIV via stem cell transplants are merely providing a few puzzle pieces to HIV research, if at all, but have no clinical applicability, as a stem cell transplant is always an extreme, dangerous and last-resort treatment for otherwise unmanageable diseases, as which HIV generally does not count anymore.
I think this is random.