Progressive multifocal leukoencephalopathy (PML), also known as progressive multifocal leukoencephalitis, is a rare and usually fatal viral disease characterized by progressive damage (-pathy) or inflammation of the white matter (leuko-) of the brain (-encephalo-) at multiple locations (multifocal).
It occurs almost exclusively in people with severe immune deficiency, such as transplant patients on immunosuppressive medications, receiving certain kinds of chemotherapy, receiving natalizumab (Tysabri) for multiple sclerosis, on long-term efalizumab (Raptiva) for psoriasis, or have AIDS.
It is caused by a virus, the JC virus, which is normally present and kept under control by the immune system. Immunosuppressive drugs prevent the immune system from controlling the virus.
Read more about Progressive Multifocal Leukoencephalopathy: Cause, Contributing Causes, Pathogenesis, Symptoms, Diagnosis, Treatment
Famous quotes containing the word progressive:
“A radical is one of whom people say “He goes too far.” A conservative, on the other hand, is one who “doesn’t go far enough.” Then there is the reactionary, “one who doesn’t go at all.” All these terms are more or less objectionable, wherefore we have coined the term “progressive.” I should say that a progressive is one who insists upon recognizing new facts as they present themselves—one who adjusts legislation to these new facts.”
—Woodrow Wilson (1856–1924)