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35 comment(s) - last by Samus.. on Dec 15 at 8:28 PM |
Timothy Ray Brown might seem very unfortunate if you knew some aspects of his medical story. A U.S. citizen living abroad in Berlin, Mr. Brown was diagnosed with acute myeloid leukemia.
As the disease spread through his bone marrow, he was forced to undergo grueling chemotherapy and then a stem cell transplant. Then the disease flared up yet again, forcing yet another stem cell transplant.
Finally recovering, he then suffered an unexpected neurological side effect, which left him forgetful and temporarily blind. He had to undergo therapy just to be able to try to walk and talk normally.
But the treatment did something incredible, something that has never before been documented in the modern medical community -- it cured Mr. Brown of the human immunodeficiency virus -- better known as HIV.
Deadly, but Effective
Approximately 1 percent of Caucasians in northern and western Europe have a special mutation that virtually prevents them from being infected with the HIV virus. The mutation, dubbed CCR5 delta 32 homozygosity, causes individuals to lack the CCR5 receptor, which the HIV lentivirus uses to accomplish its infection process.
Physicians treating Mr. Brown's cancer purposefully selected a donor who happened to have this beneficial mutation.
Hopes of a cure seemed faint, though. After all, if the HIV infection in Mr. Brown's former CD4 (T-cell) population had advanced enough, it would have developed the ability to infect using the CXCR4 receptor, rendering the protective mutation useless. And even if the virus had not armed itself with this new ability, no one had ever been cured of the disease.
While Mr. Brown may have been unfortunate by and large medically, he apparently lucked out when it came to his HIV infection.
Taken abruptly off antiretroviral drugs after the transplant, he showed no signs of HIV infection. For the next 38 months he underwent immunosuppressive treatment to protect the graft as it repopulated his intestinal mucosa.
Tissue samples taken during this time period showed spiking levels of the donor T-cells and no trace of infection. Weaning off immunosuppressants, the man's T-cell levels dropped to that of a healthy adult male.
Medical researchers concluded that it was unlikely that the man still had HIV -- after all if he had the disease, it would have likely evolved the CXCR4 infection ability and infected his immunotransplant.
Further evidence the disease was gone was shown by dropping levels of his body's HIV antibodies. And viral load testing (RNA) and tests for viral DNA within cells -- two tests that typically reveal the presence of HIV -- came back negative.
Can Doctors Replicate This Unusual Success?
Mr. Brown's ordeal was chronicled in the German magazine Stern.
The results have also been published in an article in the peer-reviewed journal Blood and astudy [PDF] in The New England Journal of Medicine.
As the magazine notes, past attempts to graft "immune" T-cells failed, due to the long lifespans of the victim's infected T-cells. Those long lifespans bought the virus enough time to mutate and overcome the graft's immunity. But in Mr. Brown's case, the chemotherapy killed enough of the infected cells that the mutation was not able to occur.
While the treatment regiment is extremely dangerous, chemotherapy -- long aimed at curing cancer -- may soon be used to cure HIV.
The key remaining obstacle is to develop ways to create CCR5 deficient T-cells.
Mr. Brown was fortunate in that a donor was found who happened to have this mutation. Most won't be that lucky. But researchers are hoping to create stem cells from the patient's various cell lines, differentiate them into T-cells, and finally using gene therapy to knock out the CCR5 receptor DNA.
The resulting treatment may not be correct for everybody. HIV is largely repressible with today's advanced drug regimens. Some may decline to risk their lives to be pronounced "cured".
For those who may someday opt for this route, the resulting treatment will likely be very expensive. Thus South Park's irreverent recent episode "Tonsil Trouble", which depicted NBA-great Magic Johnson being "cured" of HIV via a money transfusion may prove somewhat prophetic.
기술 관련 전문미디어인 데일리테크의 14일(현지시간)자 보도에 따르면 독일 베를린에 거주하고 있는 티모시 레이 브라운(사진)이 에이즈(HIV)에 감염됐다가 최근 검사 결과 완치된 것으로 나타났다.
그는 HIV 보균자인데다가 골수백혈병까지 함께 앓아 한때 사경을 헤매는 등 중태에 빠졌다. 의료진은 그를 위해 화학요법에 줄기세포 골수 이식 등 할수 있는 모든 방법을 동원했다. 브라운은 치료 도중 시력 상실, 기억력 감퇴 등 부작용을 겪기도 했다.
그러나 기적이 발생했다. 치료가 끝난 뒤 검진을 받은 결과 놀랍게도 HIV 바이러스가 모두 사라진 것으로 나타난 것. 의료진은 원인을 분석한 결과 이식된 줄기세포 기증자가 HIV에 저항성을 가진 돌연변이 유전자를 갖고 있었기 때문으로 결론지었다. `CCR5 델타 32`로 명명된 이 유전자는 코카서스 인종 중 1%만이 가지고 있는 것으로 파악됐다.
게다가 항암치료를 받느라 몸 안에 있던 백혈구들을 박멸하는 과정에서 HIV에 감염된 혈구가 많이 파괴된 것도 완치에 기여했다.
이 결과는 지난 2008년 독일 학술대회에서 발표됐지만 당시에는 완치가 아닌 지연일수도 있다는 주장이 제기되기도 했다. 그러나 2년이 지난 지금에도 재발하지 않은 것으로 파악되며 완치된 것으로 평가받고 있다. 이번 결과는 영국 의학저널에 게재됐다.
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