PML is caused by

(B) Papova virus # Human papova virus has been isolated from a number of patients with impaired immunity> J.C. virus one type of papova virus which is isolated from patient with : HIV Hodgkin lymphoma Progressive Multi focal leukoencephalopathy (PML). Progressive multifocal leukoencephalopathy (PML) is a rare and usually fatal viral disease characterized by progressive damage or inflammation of the white matter of the brain at multiple locations. It is caused by the JC virus, which is normally present and kept under control by the immune system. JC virus is harmless except in cases of weakened immune systems. PML occurs almost exclusively in patients with severe immune deficiency, most commonly among patients with acquired immune deficiency syndrome (AIDS), but people on chronic immunosuppressive medications including chemotherapy are also at increased risk of PML, such as patients with transplants, Hodgkin's Lymphoma, multiple sclerosis, psoriasis and other autoimmune diseases.