title: Potassium channel antibodies in two patients with reversible limbic encephalitis.
abstract: Limbic encephalitis (LE) is often associated with lung, thymic, or testicular tumours and antibodies to Hu, CV2, or Ma2 (Ta) antigens. In these cases, it generally has a poor prognosis. Here we describe two patients with symptoms of LE, negative for typical paraneoplastic antibodies, in whom antibodies to voltage-gated potassium channels (VGKC) were detected retrospectively in serial serum samples. Patient 1 had a thymoma recurrence, but in patient 2 no tumour has been detected in the years following presentation. Plasma exchange was effective in reducing VGKC antibody levels, with substantial improvement in mental symptoms in patient 1. In patient 2, the VGKC antibodies fell spontaneously over two years, with almost complete recovery of mental function. Although neither patient had obvious neuromyotonia at presentation, both showed excessive secretions. We suggest that patients with limbic symptoms and excessive secretions should be tested for VGKC antibodies, and, if they are present, prompt and effective immunosuppressive treatment should be considered.
authors.affiliation: Neurosciences Group, Institute of Molecular Medicine, John Radcliffe Hospital, Oxford, UK.
authors.forename: C
authors.initials: C
authors.lastname: Buckley
authors.forename: J
authors.initials: J
authors.lastname: Oger
authors.forename: L
authors.initials: L
authors.lastname: Clover
authors.forename: E
authors.initials: E
authors.lastname: Tüzün
authors.forename: K
authors.initials: K
authors.lastname: Carpenter
authors.forename: M
authors.initials: M
authors.lastname: Jackson
authors.forename: A
authors.initials: A
authors.lastname: Vincent
mesh_terms: D000368:Aged; D000906:Antibodies / Q000276:immunology*; D001921:Brain / Q000473:pathology*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D020363:Limbic Encephalitis / Q000097:blood* / Q000276:immunology* / Q000473:pathology / Q000523:psychology; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D009483:Neuropsychological Tests; D015221:Potassium Channels / Q000276:immunology*; D011863:Radioimmunoassay
chemical_list: D000906:Antibodies; D015221:Potassium Channels