Although this finding may lead to a way of predicting who is at risk for the brain infection -- called progressive multifocal leukoencephalopathy (PML) -- at this point, the implications are still unclear. "But it certainly is exploring a key question." The study authors also warned against coming to premature conclusions.

The drug seems to rouse the typically dormant JC virus from its slumber, allowing it to trenton into the brain. Sign Up for MedicineNet Newsletters. Pfizer to Pay Record Fine in Fraud Probe New Anti-Clotting Drug Beats Plavix Propofol Plus Sedative Killed Benjy Geoffry Propofol Linked to Lars Jackson's Death Xenical and Alli. Food and Drug Administration approval in only to be. "We don't know what this means until we find out over time whether or not people actually do get PML," said Amalea O'Looney, vice president of biomedical research at the National Multiple Sclerosis Society in New York City.

"We don't advocate a change in management [of the disease] at this point because the clinical relevance of these findings is still unknown," said Dr.

Koralnik, senior "But it should spur further research." Natalizumab (Tysabri) first received U.S.