4 ms·
Yes, it's a virus, specifically a lentivirus, which inserts its own genome into the cells DNA, including the therapeutic gene. Looks like they first extract bon
by bglazer 4y ago
Yes, it's a virus, specifically a lentivirus, which inserts its own genome into the cells DNA, including the therapeutic gene. Looks like they first extract bone marrow from a patient, apply the virus which adds the gene, then they put the "fixed" bone marrow cells back into the patient (probably after killing most existing bone marrow through some really unpleasant procedures). The re-inserted, treated cells then expand and begin making new cells that have inherited the fixed gene.
In general, gene therapy is probably most useful currently for diseases that affect the bone marrow (and the eyes), because these are two tissues where you can precisely deliver the virus. It's still challenging to control where the virus goes and which cells it infects if you just inject it straight into the bloodstream.
- meese712 4y agoI'm confused how this would reduce disease progression compared to a much cheaper allo bone marrow transplant then if they are only modifying hematopoietic stem cells since a BMT is just doing the exact same thing except with someone else's non affected cells. BMTs are a horrific procedure though so this definitely has an advantage in that regard. I would also have to imagine they would have to do myeloablative chemo or radiation to make sure the fixed cells propagate more than the diseased cell line. Edit: read the study, they do give them the same chemo used for normal transplants.
- theGnuMe 4y agoWell it removes graft vs host complications which is a win and the requirement to take immunosuppressants for life.
- meese712 4y agoDefinitely true GVHD sucks. The article gave me the impression that they were saying it was somehow superior at stopping the disease because it said this "stem cell transplants, have sometimes been used to slow the disorder's progression in infants," (fyi a decent amount of stem cell transplant survivors do not have to take immunosuppressants for life)
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- piyh 4y agoMost recipients don't need to take immunosuppressants at all if they get PBSC or bone marrow transplants. Even if they do, it's short term. Additionally, the allo grafts need to be matched, which if you're non white is not a good success rate. 85%ish of whites get matched, that number gets depressingly low for minorites. On the US registry, only 1 in 400 donors get called. I happen to be one of those donors and a system where I'm not needed is a better one. The best part is no part. https://ashpublications.org/blood/article/104/12/3501/89040/Duration-of-immunosuppressive-treatment-for https://ashpublications.org/blood/article/104/12/3501/89040/... >Previous studies have shown that 30% to 70% of all patients surviving beyond 100 days after HCT require treatment for chronic GHVD,2,4-6 often for more than 2 years. Re: a better system is where you don't need donors: https://www.cbsnews.com/newyork/news/l-i-woman-dies-after-marrow-donors-refuse-to-show/ https://www.cbsnews.com/newyork/news/l-i-woman-dies-after-ma...
- meese712 4y agoI was getting at the article giving the impression this somehow cured the disease vs a BMT just slowing progression. I know the whole transplant thing sucks. I've had two transplants, thank you for being on the list :).
- tialaramex 4y agoThe article indicates they don't know. "it is not yet clear whether it will persist life-long, and extended follow-up is needed" - So they can be optimistic without knowing for sure because they don't have a bunch of kids they treated say ten years ago to check on. It seems like this might stick, they hope it will, they can't know yet. One of my friends gave his wife a kidney which allowed her to get off dialysis, so yeah, thanks to anybody who is willing to do this for someone they don't even know.
- jimbob45 4y agoWhat’s the story with minorities? Just a smaller pool of donors or something?
- 4y ago
- Gatsky 4y agoReading the paper [1], the genetically modified stem cells overexpress the ARSA enzyme. This seems to create a ‘bystander effect’ which increases the total body enzymatic activity above some critical threshold sufficient to arrest the disease process. Myeloid cells associated with neuronal structures are probably critical to this benefit. A standard bone marrow transplant doesn’t reach this threshold, and has demonstrated poor efficacy in early onset disease.
- fnord77 4y ago> probably after killing most existing bone marrow through some really unpleasant procedures usually a massive dose of radiation, right?
- azernik 4y agoThat or chemo
- rmk 4y agoSo is the idea here that the 'fixed' cells populate the body and form the basis of all future generations of cells that are produced in the bone marrow?
- bglazer 4y agoYep!
- stavros 4y agoMy 3-year-old niece got her eyes treated for some degenerative disease in the same way. It's amazing what science can do now, a few months earlier and she would have gone blind before her next birthday.
- jeffreyrogers 4y agoIt would probably also be useful for HIV since white blood cells are produced in the bone marrow.
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