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Comment by ccooffee | Hacker News Reader

I've had an allogenic stem cell transplant. It was hell. I no longer have cancer, so it was worth it. But HIV/AIDS (with standard treatment and testing) no longer significantly reduces life expectancy.

I have a hard time imagining a future where allogenic stem cell transplants are used to treat HIV. The procedures are incredibly risky and carry long term consequences (and in many cases, like mine, also unbearably painful for weeks).

To me, the most likely practical consequence of these findings is to spur on interest in using CRISPR (or other in-vivo genetic modification strategies) to alter the genome of an HIV patient to be "immune" to HIV. (A similar idea is used in treatment of some blood cancers. Chase the rabbit-hole of "CAR T Cell therapy" to get started.)

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This explanation for the technique’s general inapplicability is touched on in the article.

It sounds like all of the HIV-cured were people that had a blood cancer that was, presumably, not responding to chemo, and for which they needed to get a new blood-making system grafted in. And, since this extremely risky procedure was a sunk cost, they rolled in the stem cell donor having an HIV resistant mutation as a might-as-well-since-we’re-in-there freebie while treating the blood cancer with a last ditch effort.

Inducing the HIV resistant mutation by other means is clearly the general way to go.

Finding an optimal donor match (via HLA typing) rarely returns many "perfect" matches. Perhaps there are systems that record both the CCR5 mutation and HLA typing, but I'd expect most donor matches, found via registries like https://bethematch.org/, will not have that information available.

I haven't dug into the weeds here (and, for personal emotional reasons, I will not), but I find it hard to believe the medical staffs would have seriously considered "can we find a donor that matches AND will possibly cure the HIV". The diagnosis-to-death timeline for many blood cancers is fast when other treatments don't work. Delaying a transplant by 2 weeks in order to find a slightly more optimal donor seems crazy. (Though I suppose the after-transplant care for someone with HIV might be trickier than those without HIV. But patients will be immune-compromised for at least months post-transplant, so maybe HIV isn't that big of a deal.)

Indeed the article does not mention anything about the donors being chosen with HIV resistance in mind. So there is a good chance of this being a welcome side effect to the cancer treatment but not intentional.

HIV, in rich countries at least, is a managed condition these days. I'd imagine the only issues would be any sort of interactions between the don't-get-AIDS cocktail and the cancer drugs.

Perhaps the matching system has more data in Germany, or perhaps they really are just writing up happy accidents in which they discover that the patient lucked into a CCR5 donor and also already had low enough levels of HIV that the operation made a difference.

> I find it hard to believe the medical staffs would have seriously considered "can we find a donor that matches AND will possibly cure the HIV".

According to a report of the Tagesschau (belonging to the German public television chanel ARD),[1] the patient had leukemia and the doctors were looking for a fitting donor who was also missing a so-called CCR5 co-receptor. According to the report, people having such a gene mutation can be found especially in Central and Northern Europe.

The patient had already been treated in 2018, but is only now considered cured because he has not experienced any HIV symptoms since then.

I do not know whether it was relevant in this case, but Germany has a Central Bone Marrow Donor Registry with currently almost 10 million people registered.[2]

[1] See https://www.tagesschau.de/wissen/gesundheit/hiv-leukaemie-st... (in German)

[2] See https://www.zkrd.de/neue-spender-weiterhin-gesucht/ (in German)

I read a little about allogenic stem cell transplants and it really sounds risky and more of a last chance type option.

"Last chance" describes both the way it was introduced to me by my medical team, and the circumstances around my SCT. I don't know how factually accurate it is, but my medical team had said there's about a 30% mortality rate caused by the SCT within about 90 days. (And, prior to chemotherapy ceasing to work, I'd been repeatedly reassured by medical staff with "chemo sucks but it isn't gonna kill you like a stem cell transplant would!")

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