September 25, 2015
The JC virus is usually not harmful, unless the infected person has a weakened immune system, as is the case of MS patients under immunosuppressive medications. In these cases, the JC virus can opportunistically infect the brain and induce a rare, often fatal brain disease called progressive multifocal leukoencephalopathy (PML), which is characterized by inflammation and progressive damage of the white matter of the brain.
“In healthy people, the disease never breaks out as the immune system keeps it well under control. Once the immune system is compromised, however, such as in patients with tumors, leukemia, AIDS, autoimmune diseases and certain immunosuppressive treatments, the JC virus is able to alter its genetic information and infect the brain,” explained the co-author of both studies Dr. Roland Martin from the University of Zurich in a news release
One well-known case is the use of the humanized monoclonal antibody Tysabri
) as a therapy for MS, which has been associated with the development of PML. It is thought that while the antibody prevents immune cells from reaching the brain, it also blocks its immunosurveillance system. It is estimated that more than 560 MS patients in the world have developed PML, and of these, 20% died from the disease, as there is no treatment available for JC virus infection.
Now, researchers report that there is a possible vaccination approach to preventing PML, or, if a person’s brain is already infected, a treatment with virus-specific human antibodies.