November 13, 2008

Marrow Transplant Appears To Have Cured AIDS

Doctors were happy to announce Wednesday that a 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.

Researchers warn the case may be a fluke, while others contend it could inspire a greater interest in gene therapy to fight the disease that claims 2 million lives each year.

Worldwide, the virus has infected 33 million people.

Dr. Gero Huetter said his 42-year-old anonymous patient, an American living in Berlin, had been infected with the AIDS virus for more than a decade.

However, he no longer shows signs of the virus.

"We waited every day for a bad reading," Huetter said.

Researchers at Berlin's Charite Hospital and medical school claim tests on his bone marrow, blood, and other organ tissues have all been clean.

Dr. Andrew Badley, director of the HIV and immunology research lab at the Mayo Clinic in Rochester, Minn., warned those initial tests were not extensive enough.

"A lot more scrutiny from a lot of different biological samples would be required to say it's not present," Badley said.

During 1999, an article in the journal Medical Hypotheses reviewed the results of 32 attempts to cure AIDS reported between 1982 and 1996. In two cases, HIV was apparently eradicated, the review reported.

Huetter's anonymous patient was undergoing treatment at Charite for both AIDS and leukemia.

Huetter is a hematologist, not an HIV specialist so he prepared to treat the patient's leukemia with a bone marrow transplant, but he remembered 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 said. "I remembered it and thought it might work."

Experts believe about one in 1,000 Europeans and Americans have inherited the mutation from both parents, so Huetter searched for one such person among donors that matched the patient's marrow type.

The patient endured powerful drugs and radiation to kill off his own infected bone marrow cells and disable his immune system before the transplant.

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 an initial cure.

However, he said the success could inspire researchers to pursue gene therapy as a means to block 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.

Even for the patient in Berlin his future is uncertain, because he does not understand why his AIDS went away.

"The virus is wily," Huetter said. "There could always be a resurgence."