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Jul 03 2013

HIV patients appear cured after receiving marrow transplant

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Two men with HIV are now free of the virus after a bone marrow transplant to treat lymphoma. But how that happened is a mystery for now.

NY Daily News — Last July Henrich first reported that the two men had undetectable levels of HIV in their blood after their stem-cell treatment, but at that time they were still taking medicines to suppress HIV. Using stem-cell therapy is not seen as a viable option for widespread use, since it is extremely expensive, but the latest cases could open new avenues for fighting the disease, which infects about 34 million people worldwide.
The latest cases resemble that of Timothy Ray Brown, known as “the Berlin patient”, who became the first person to be cured of HIV after receiving a bone marrow transplant for leukaemia in 2007. There are, however, important differences. While Brown’s doctor used stem cells from a donor with a rare genetic mutation, known as CCR5 delta 32, which renders people virtually resistant to HIV, the two Boston patients received cells without this mutation.

Many viruses including HIV gain entry to the cell using a special portal on the cell’s surface in a process called Receptor Mediated Endocytosis. Individuals with one copy of the CCR5 mutation have fewer functional receptors thus making them highly resistance to those kinds of viruses, people with two copies are virtually immune. Ergo, it’s understandable why a marrow transplant from an individual carrying that mutation might confer some resistance on the recipient. But why it happened in these two latest cases, where that marker was absent, is not clear.

As a non expert I’ll go ahead and guess at one possibility though. Prior to a marrow transplant most patients take a big dose of poison that kills off their native bone marrow (We can actually completely cure marrow malignancies like leukemia in many cases, the problem is that cure kills the patient, we need bone marrow to survive). HIV often hides in that material, so if that refuge was destroyed and the virus was under control elsewhere in the system via existing drugs, it could explain these results.

8 comments

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  1. 1
    CaitieCat, in no way a robot nosireebot

    It’s a remarkable result, and a hopeful one. I’ve lost too many friends to this evil little fucker.

  2. 2
    Randomfactor

    Wonder if they’ll start testing bone-marrow registry folks for the double-CCR5 mutation. They may be very popular…

  3. 3
    anubisprime

    CCR5-Δ32 is an increasingly curious little critter.

    I saw a Discovery special yonks ago…and they were highlighting the the apparent anomaly of the village of Eyam, and the apparent immunity several families had from the plague, and the possibility that CCR5-Δ32 was somehow a factor, seems that descendants have been above prediction in expressing that critter in the subsequent bloodlines.
    Although that was no guarantee that the CCR5-Δ32 was in fact the barrier at the time is does strongly suggest that possibility.
    Then the programme moved on to discuss the effect of that genetic template with regards to HIV…it’s action seemed to confer a barrier there as well.

    This was of course years ago, but even back then it certainly grabbed my interest.

    Strange how it seems to have surfaced in this study, but one can only hope it is the magic spell that breaks this insidious and vicious abomination of a disease.
    To many folks…to many broken dreams…it is enough!

  4. 4
    kemist, Dark Lord of the Sith

    Using stem-cell therapy is not seen as a viable option for widespread use, since it is extremely expensive

    Not only expensive, but also pretty risky. A significant fraction of people who undergo bone marrow transplants develop GVDH (graft versus host disease), a potentially debilitating and sometimes lethal complication in which the transplanted immune system attacks the host’s body.

    The risk is acceptable in someone who faces a very likely short term death from leukemia, but maybe not in a case of adequately managed HIV infection.

  5. 5
    CaitieCat, in no way a robot nosireebot

    Totally, kemist – but it’s very encouraging that they’re finding ways that the virus can be wiped out in corpore, and suggests that there are paths to be followed that might deliver a viable treatment. Just demontrating that more than one person has been able to be successfully treated is good science in action, even if we don’t know how yet, or how to make it widely available. Progress is better than not-progress; at least now we have a more evidenced belief that it can be done.

  6. 6
    Peter Thom

    There is a newer bone marrow transplant procedure, nonmyeloablative stem-cell transplantation, which has already demonstrated a 90% cure rate in adults with sickle cell disease. The process does not require killing all of the host’s bone marrow. I’m not certain this technique could apply in other diseases, but the idea is that by killing a large percentage, but not all of the host’s marrow cells the healthy cells injected will, over time, out-populate the remaining disease-state cells. This procedure is far less toxic than myeloablative transplants posing far less risks to patients.

    http://www.nejm.org/doi/full/10.1056/NEJMoa0904971

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