PROGRESSIVE MULTIFOCAL LEUKOENCEPHALOPATHY FOLLOWING IMMUNOMODULATORY THERAPY

Progressive multifocal leukoencephalopathy (PML) is a demyelinating disease of central nervous system. It is caused by JC virus, a human Polyomavirus (DNA virus) belonging to Papovaviridae group. PML is the result of reactivation of latent JC virus infection in the setting of cellular immunodeficiencies. Cases associated with HIV account for 85 of all cases .Another association of PML , is following treatment with Natalizumab , an immunomodulatory agent. This case report describes PML occurring in a patient of multiple sclerosis ,treated with natalizumab.