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2008-11-13 09:38:52
By PATRICK McGROARTY, Associated Press Writer Patrick Mcgroarty, Associated
Press Writer 1 hr 17 mins ago
BERLIN An American man who suffered from AIDS appears to have been cured of
the disease 20 months after receiving a targeted bone marrow transplant
normally used to fight leukemia, his doctors said.
While researchers and the doctors themselves caution that the case might be
no more than a fluke, others say it may inspire a greater interest in gene
therapy to fight the disease that claims 2 million lives each year. The virus
has infected 33 million people worldwide.
Dr. Gero Huetter said Wedneday his 42-year-old patient, an American living in
Berlin who was not identified, had been infected with the AIDS virus for more
than a decade. But 20 months after undergoing a transplant of genetically
selected bone marrow, he no longer shows signs of carrying the virus.
"We waited every day for a bad reading," Huetter said.
It has not come. Researchers at Berlin's Charite hospital and medical school
say tests on his bone marrow, blood and other organ tissues have all been
clean.
However, Dr. Andrew Badley, director of the HIV and immunology research lab at
the Mayo Clinic in Rochester, Minn., said those tests have probably not been
extensive enough.
"A lot more scrutiny from a lot of different biological samples would be
required to say it's not present," Badley said.
This isn't the first time marrow transplants have been attempted for treating
AIDS or HIV infection. In 1999, an article in the journal Medical Hypotheses
reviewed the results of 32 attempts reported between 1982 and 1996. In two
cases, HIV was apparently eradicated, the review reported.
Huetter's patient was under treatment at Charite for both AIDS and leukemia,
which developed unrelated to HIV.
As Huetter who is a hematologist, not an HIV specialist prepared to treat
the patient's leukemia with a bone marrow transplant, he recalled that some
people carry a genetic mutation that seems to make them resistant to HIV
infection. If the mutation, called Delta 32, is inherited from both parents, it
prevents HIV from attaching itself to cells by blocking CCR5, a receptor that
acts as a kind of gateway.
"I read it in 1996, coincidentally," Huetter told reporters at the medical
school. "I remembered it and thought it might work."
Roughly one in 1,000 Europeans and Americans have inherited the mutation from
both parents, and Huetter set out to find one such person among donors that
matched the patient's marrow type. Out of a pool of 80 suitable donors, the
61st person tested carried the proper mutation.
Before the transplant, the patient endured powerful drugs and radiation to kill
off his own infected bone marrow cells and disable his immune system a
treatment fatal to between 20 and 30 percent of recipients.
He was also taken off the potent drugs used to treat his AIDS. Huetter's team
feared that the drugs might interfere with the new marrow cells' survival. They
risked lowering his defenses in the hopes that the new, mutated cells would
reject the virus on their own.
Anthony Fauci, director of the National Institute of Allergy and Infections
Diseases in the U.S., said the procedure was too costly and too dangerous to
employ as a firstline cure. But he said it could inspire researchers to pursue
gene therapy as a means to block or suppress HIV.
"It helps prove the concept that if somehow you can block the expression of
CCR5, maybe by gene therapy, you might be able to inhibit the ability of the
virus to replicate," Fauci said.
David Roth, a professor of epidemiology and international public health at the
London School of Hygiene and Tropical Medicine, said gene therapy as cheap and
effective as current drug treatments is in very early stages of development.
"That's a long way down the line because there may be other negative things
that go with that mutation that we don't know about."
Even for the patient in Berlin, the lack of a clear understanding of exactly
why his AIDS has disappeared means his future is far from certain.
"The virus is wily," Huetter said. "There could always be a resurgence."