The patient in question was a 42-year-old American living in Berlin who was undergoing a bone marrow transplant at that city's Charite hospital.

The bone-marrow donors were selected because they possessed a rare HIV-resistant genetic mutation since the man had to stop taking AIDS-inhibiting medication for the cancer treatment to work.

On Wednesday, Nov. 12, doctors announced that after two years of treatment, not only had the patient not contracted AIDS -- his blood now appeared to be clear of HIV infection.

"There is no longer demonstrable evidence that the patient is infected," Eckhard Thiel, Director of Charite's Clinic for Hematology and Oncology, told reporters. "We're very happy and proud to have achieved this breakthrough."

Thiel added that the result was the first of its kind ever recorded in the world.

The question is now: What could it mean in the search for a cure for HIV-AIDS?

No immediate remedy

Scientists cautioned that the fact that the HIV virus can no longer be detected in the patient's blood stream does not necessarily mean it is absent from his entire body.

"The HIV virus could be in the spleen, the lymph nodes, the nerve cells -- anywhere really," Norbert Brockmeyer, a clinic director at the university hospital of Bochum, told the online edition of the news magazine Der Spiegel.

And even if effective against HIV, several factors argue against the idea that similar treatments could be carried out on a wide-spread basis.

Bone marrow transplants and the accompanying chemotherapy are themselves dangerous procedures, and the patient in question was fortunate in having a genetic make-up that allowed for an unusually high number of potential donors.

Charite doctors say they are monitoring the patient's health and are prepared to put him back on anti-retroviral drugs if the HIV infection reappears.

"We cannot say with certainty that the virus won't begin replicating itself in the future," Thomas Schneider, Charite's Director of Infectology, told a press conference. "But the mere fact that it hasn't yet done so, is a minor sensation."

More research will be needed to determine what exact significance, if any, the breakthrough at the Charite has for the overall fight against AIDS.

Today, more than 38 million people, mostly in Africa and Asia, are estimated to be infected with HIV, the virus which causes AIDS.