INTRODUCTION: Voltage-gated Kv1 potassium channel complex (VGKC) autoantibodies subtyped for leucine-rich glioma-inactivated 1 (LGI1), contactin-associated-proteinlike 2 (CASPR2), and Kv IgGs have a spectrum of neurological presentations. Painful polyneuropathy is seen in some patients, but nerve pathology descriptions are lacking. METHODS: Clinicopathologic features were studied in subtyped VGKC-autoantibody-seropositive patients who had undergone nerve biopsies. RESULTS: Five patients were identified, 1 LGI1 IgG positive and 1 CASPR2 IgG positive, but all negative for Kv1.1-, 1.2-, 1.6-subtyped IgG autoantibodies. Median symptom duration was 17 months. Pain was the predominant symptom; 3 had mild sensory loss and/or weakness. Histopathological abnormalities were limited to axonal loss in 3. None had mononuclear cellular infiltrates. Electron micrographs revealed no interstitial abnormalities. Three patients reported marked improvement in pain with immunotherapy. CONCLUSIONS: The nerve biopsy histopathology of patients subtyped for LGI1 and CASPR2 IgGs within the VGKC-complex spectrum disorders shows either normal density or axonal fiber loss without inflammatory infiltrates. A reversible neural hyperexcitable mechanism is considered to be the cause of this painful polyneuropathy. Muscle Nerve 55: 520-525, 2017.
INTRODUCTION: Voltage-gated Kv1 potassium channel complex (VGKC) autoantibodies subtyped for leucine-rich glioma-inactivated 1 (LGI1), contactin-associated-proteinlike 2 (CASPR2), and Kv IgGs have a spectrum of neurological presentations. Painful polyneuropathy is seen in some patients, but nerve pathology descriptions are lacking. METHODS: Clinicopathologic features were studied in subtyped VGKC-autoantibody-seropositive patients who had undergone nerve biopsies. RESULTS: Five patients were identified, 1 LGI1 IgG positive and 1 CASPR2 IgG positive, but all negative for Kv1.1-, 1.2-, 1.6-subtyped IgG autoantibodies. Median symptom duration was 17 months. Pain was the predominant symptom; 3 had mild sensory loss and/or weakness. Histopathological abnormalities were limited to axonal loss in 3. None had mononuclear cellular infiltrates. Electron micrographs revealed no interstitial abnormalities. Three patients reported marked improvement in pain with immunotherapy. CONCLUSIONS: The nerve biopsy histopathology of patients subtyped for LGI1 and CASPR2 IgGs within the VGKC-complex spectrum disorders shows either normal density or axonal fiber loss without inflammatory infiltrates. A reversible neural hyperexcitable mechanism is considered to be the cause of this painful polyneuropathy. Muscle Nerve 55: 520-525, 2017.
Authors: Sophie N M Binks; Christopher J Klein; Patrick Waters; Sean J Pittock; Sarosh R Irani Journal: J Neurol Neurosurg Psychiatry Date: 2017-10-21 Impact factor: 10.154
Authors: David L Bennett; Sarosh R Irani; Sudarshini Ramanathan; Mandy Tseng; Alexander J Davies; Christopher E Uy; Sofija Paneva; Victor C Mgbachi; Sophia Michael; James A Varley; Sophie Binks; Andreas C Themistocleous; Janev Fehmi; Yaacov Anziska; Anushka Soni; Monika Hofer; Patrick Waters; Fabienne Brilot; Russell C Dale; John Dawes; Simon Rinaldi Journal: Ann Neurol Date: 2021-08-30 Impact factor: 11.274