title: Progressive multifocal leukoencephalopathy after natalizumab monotherapy.
abstract: We describe progressive multifocal leukoencephalopathy (PML) caused by infection with human polyomavirus JC virus in a patient with multiple sclerosis who was treated with natalizumab. The first PML symptoms appeared after 14 monthly infusions of the drug. Magnetic resonance imaging (MRI) showed a presumed multiple sclerosis lesion, and JC virus DNA was not detected on polymerase-chain-reaction (PCR) assay of cerebrospinal fluid. The patient's symptoms worsened, and the diagnosis of PML was established with a more sensitive quantitative PCR assay after 16 infusions of natalizumab. Plasma exchange was used to accelerate clearance of natalizumab. Approximately 3 weeks after plasma exchange, an immune-reconstitution inflammatory syndrome appeared. JC virus DNA was no longer detectable on quantitative PCR assay, and the patient's symptoms improved.
authors.affiliation: Neurology Unit, Division of Internal Medicine, Danderyd Hospital, Karolinska Institutet, Stockholm, Sweden. hans.linda@ki.se
authors.forename: Hans
authors.initials: H
authors.lastname: Lindå
authors.forename: Anders
authors.initials: A
authors.lastname: von Heijne
authors.forename: Eugene O
authors.initials: EO
authors.lastname: Major
authors.forename: Caroline
authors.initials: C
authors.lastname: Ryschkewitsch
authors.forename: Johan
authors.initials: J
authors.lastname: Berg
authors.forename: Tomas
authors.initials: T
authors.lastname: Olsson
authors.forename: Claes
authors.initials: C
authors.lastname: Martin
mesh_terms: D000328:Adult; D000911:Antibodies, Monoclonal / Q000009:adverse effects* / Q000627:therapeutic use; D061067:Antibodies, Monoclonal, Humanized; D001921:Brain / Q000473:pathology; D004279:DNA, Viral / Q000097:blood; D006801:Humans; D054019:Immune Reconstitution Inflammatory Syndrome / Q000209:etiology; D039441:Integrin alpha4 / Q000276:immunology*; D007577:JC Virus / Q000235:genetics / Q000276:immunology; D007968:Leukoencephalopathy, Progressive Multifocal / Q000139:chemically induced* / Q000276:immunology; D008279:Magnetic Resonance Imaging; D008297:Male; D009103:Multiple Sclerosis / Q000150:complications / Q000188:drug therapy* / Q000473:pathology; D000069442:Natalizumab; D016133:Polymerase Chain Reaction
chemical_list: D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D004279:DNA, Viral; D000069442:Natalizumab; D039441:Integrin alpha4