Aside

Could Bone Marrow Transplant Treat HIV?

Hey there Guys,

You may remember there was a bit of press last year about a man who was cured of HIV after a bone marrow transplant.

To bring up you to speed, as noted in The Vienna Review:

In 2007, Timothy Ray Brown, referred to as the ‘Berlin Patient,’ received a rare stem cell transplant treatment to combat myeloid leukemia, a cancer of the immune system. Cancer was the form AIDS had taken with this particular victim. By the end of 2010, Brown was cured of the cancer and no traces of HIV remained in his system.

This development has been seen as a promising and exciting step forward in the fight against AIDS, as well as a pat on the back for stem-cell research. Nonetheless, the medical and scientific communities have urged the public not to celebrate yet. By all means, safe sex should continue to be practiced. The treatment was a rare and difficult one to replicate.

Most important, Brown’s recovery was due to a particular characteristic of the donor’s genetic makeup. The individual whose bone marrow had been used was one of a small percentage of Europeans said to be immune to HIV. Bone marrow is where much of the body’s blood components are produced, including CD4 T-cells. This cell, responsible for the identification of infections, is the specific target of HIV. However, in those individuals considered immune, CD4 T-cells are unaffected when exposed to the virus. Timothy Brown seems to have acquired the donor’s same immunity. Since beginning this treatment, he has discontinued his use of HIV medication and now, three years later, he is completely free of the virus.

Today new research has emerged about experiments to see if bone marrow transplants could be useful for eradicating HIV from the body. A small study was done in which stem cells, a type of cell that can transform into other cell types, were extracted from bone marrow, then retransplanted after the existing immune system was killed with chemotherapy.

The rational behind this is to rid the body of HIV infected cells, in particular the immune system.

As noted in The Aids Beacon:

Results from a small study indicate that high-dose chemotherapy plus stem cell transplantation in which participants received a transplant with their own stem cells is insufficient to cure HIV in people with HIV.

“Nine of 10 patients were viremic [had HIV in the blood] post autologous stem cell transplantation,” said Anthony Cillo, a researcher from the University of Pittsburgh and one of the study investigators.

The tenth patient did not have detectable HIV in his blood, but did have HIV genetic material detectable in his cells, indicating that he was still infected with HIV.

Reasons for this are hypothesised:

Cillo suggested that the results help clarify exactly how Brown was cured of HIV.

Brown, who was diagnosed with leukemia, was cured of HIV after receiving a bone marrow transplant from a carefully selected donor who was immune to HIV.

However, Cillo noted that in addition to a stem cell transplant, Brown received a number of treatments, including chemotherapy, total body irradiation, and treatment with immune suppressing drugs aimed at reducing the risk of the transplanted cells attacking his own body.

“Which of these treatments [received by Brown] were necessary to cure HIV remains unknown – some versus all of these treatments may have led to the first cure of HIV,”

It is important to note that the treatment Tim Brown received in Germany was a very intensive, expensive, and unique. Basically his complete immune system was killed, sterilising the body and then replaced with the bone marrow of a donor with the rare genetic defect that can protect against HIV. The expense and complexity would make it not accessible to majority of people. While at this point it appears unfeasible to replicate this treatment there is hope for the future with it’s findings.

Clearly there is hope in learning more about the particular genetic defect that leads to people being unable to become infected with HIV. If this gene is able to be harnessed there could be hope for developement of future treatments as well as potential vaccines that could block HIV before it could infect individual cells.

It’s an interesting world of research out there. Any thoughts? Please feel free to share in the comment box below.

Yours in good health.

Dr George

 

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