[HN Gopher] Fourth patient seemingly cured of HIV
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Fourth patient seemingly cured of HIV
Author : vinni2
Score : 81 points
Date : 2022-07-27 15:31 UTC (7 hours ago)
(HTM) web link (www.bbc.co.uk)
(TXT) w3m dump (www.bbc.co.uk)
| tiahura wrote:
| So bone marrow transplant from someone with natural resistance
| (the same gene as the Chinese CRISPR kids?)?
|
| Wouldn't this have happened by chance before 6-7 years ago when
| the first case was reported?
| jfengel wrote:
| They couldn't do it at all until they had really good HIV-
| suppressing drugs. You won't do a transplant into somebody with
| an active HIV infection.
|
| They still won't do it if they can avoid it. This an extreme
| measure, killing off the entire immune system and replacing it.
| They still need to find a donor who is sufficiently compatible,
| and then has the right set of genes.
|
| So it just took time for all of the pieces to fall into place.
| imtringued wrote:
| Use this to treat diabetes type one, do a pancreas transplant
| and replace the immune system so it does not reject the
| transplant.
| jfengel wrote:
| That would be fantastic, but there are enormous tradeoffs.
| This is massive, massive surgery that comes incredibly
| close to killing the patient.
|
| They are unlikely to do it if the disease can be controlled
| with an insulin pump, which is far less invasive. Insulin
| pumps are far from perfect solutions. (Somebody close to me
| has one and I can observe what a massive pain in the ass it
| is, among other places.) But surgery like this is going to
| have to come a long way before it's routine enough to
| replace a therapy that is aggravating but sufficient.
| sp332 wrote:
| Usually, just the transplant part is sufficient.
| https://connect.mayoclinic.org/blog/podcasts/newsfeed-
| post/h...
| looperhacks wrote:
| It's mentioned in the comments of the article, but "just
| the transplant" is not really enough. You still need
| heavy immune suppressants, which is rarely worth the side
| effects.
| [deleted]
| michaelmcdonald wrote:
| I'm guessing that HIV positive patients who also develop a type
| of cancer that can receive bone marrow transplants as treatment
| are rare. Bone marrow matches are extremely rare. Add to that:
| bone marrow matches with the particular mutation (CCR5-delta
| 32) can only compound that rarity. All this adds up to poor
| odds.
| gojomo wrote:
| Indeed. But rapid advances in genetic therapies mean it may
| someday be possible to 'upgrade' a patient's existing marrow
| in-place, with just the necessary new genes.
| inasio wrote:
| The first two cured patients (unsure about the third) were also
| cured by a similar bone marrow transplant from a resistant donor
| (and I think leukemia was also present?). This is good news, as
| validation of the other cases, but it still remains an infeasible
| path for the vast majority of HIV positive people.
| mindcrime wrote:
| True. But maybe additional confirmation that this pathway
| really works will help spur research into a way to replicate
| the same effect, without requiring the full bone marrow
| transplant process?
| rst wrote:
| What makes HIV hard to eliminate is that it persists in bone
| marrow. What's happening in these transplants, in cancer
| patients who also have HIV, is that the patient's original
| bone marrow (having become cancerous) is killed off and
| completely replaced, taking the HIV with it. And killing off
| the original bone marrow is the nastiest part of the
| procedure by far (source: my uncle went through it) -- but
| that's what gets rid of the HIV. Anything that replicates
| that effect would be an alternative transplant process, not
| an alternative to one.
| hn_throwaway_99 wrote:
| > What's happening in these transplants, in cancer patients
| who also have HIV, is that the patient's original bone
| marrow (having become cancerous) is killed off and
| completely replaced, taking the HIV with it.
|
| That's not accurate. If that were the case, then ANY bone
| marrow transplant could potentially cure an HIV patient.
| What's happening is that bone marrow is what generates
| white blood cells, and the donor in this case was naturally
| resistant to HIV due to the CCR5 delta 32 mutation. This
| results in white blood cells that HIV can no longer easily
| enter.
|
| So what's happening is ALL of the patient's white blood
| cells are being replaced (rather, generated by this new
| donor marrow) with ones that are resistant to HIV.
| theplumber wrote:
| What stops us from inducing a CCR5 delta 32 mutation in
| hiv infected people?
| mrguyorama wrote:
| What process do we have to reliably mutate every single
| cell of certain types in bone marrow, with only a desired
| mutation and no other?
| [deleted]
| rst wrote:
| Thanks for the correction.
| hn_throwaway_99 wrote:
| > But maybe additional confirmation that this pathway really
| works will help spur research into a way to replicate the
| same effect, without requiring the full bone marrow
| transplant process?
|
| Doubtful. It's been known for a long time that the CCR5-delta
| 32 mutation conveys HIV resistance because it results in a
| different CCR5 coreceptor which HIV uses to enter white blood
| cells (this is the whole reason the bone marrow donor was
| selected in the first place).
|
| Thus, the bone marrow transplant process works because now
| ALL of this patient's cells have that different, resistant
| CCR5 coreceptor. Hard to imagine a way to replicate this
| process without some method that results in all new white
| blood cells being generated like this.
| mindcrime wrote:
| Fair enough.
| jjtheblunt wrote:
| How can they claim a cure for a retroviral infection, which
| rewrites host genomes in cells? They can claim to obtain
| significant purge of cells with rewritten genomes?
|
| I'm missing some fundamental explanation where the rift between
| soundbites and science seems large.
| actually_a_dog wrote:
| The bone marrow transplant is from a person with a gene that
| makes their white blood cells resistant to the virus. Once the
| person's old WBCs are gone (killed by chemotherapy in the case
| of leukemia patients, which, IIRC, all these patients were due
| to the danger inherent in bone marrow transplants), the new
| bone marrow then produces only resistant cells.
| jjtheblunt wrote:
| so that presumes HIV didn't infect any other reproducing
| cells?
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