this article that I found out there:
for Psoriasis Drug deaths related to progressive multifocal leukoencephalopathy
Three deaths from progressive multifocal leukoencephalopathy (PML) and a possible fourth case has been reported in patients taking the immunosuppressant drug efalizumab (Raptiva Genentech, Inc.), according to a public health advisory issued today by the U.S. Food and Drug Administration
According to the FDA, the 4 patients were taking efalizumab for at least 3 years and had not taken any other immunosuppressive drug. The FDA advised doctors and patients receiving efalizumab and those who have left the drug, and periodically reassess whether patients should continue treatment.
A box warning was added to efalizumab in October 2008 to highlight the risk of life-threatening infections, including PML - a rare incurable brain infection, but that leads to irreversible brain dysfunction and death.
The FDA is reviewing these cases of PML, according to a notice sent today to MedWatch, the FDA safety information and reporting program for adverse events. "The agency will take appropriate measures to ensure that the risks of Raptiva not outweigh its benefits, patients prescribed Raptiva are clearly informed of the signs and symptoms of PML, and that health professionals monitor patients carefully for the possible development of PML, "according to the advice of public health.
Efalizumab is an antibody anti-CD11a indicated as immunosuppressive drugs for the treatment of adults with chronic plaque psoriasis of moderate to severe.