title: Progressive multifocal leukoencephalopathy in the biologic era: implications for practice. Introduction.
authors: Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH, USA.
authors: Leonard
authors: L
authors: Calabrese
mesh_terms: D001691:Biological Therapy / Q000009:adverse effects*; D006801:Humans; D007968:Leukoencephalopathy, Progressive Multifocal / Q000453:epidemiology* / Q000209:etiology / Q000628:therapy