title: Clinical-pathologic correlations in voltage-gated Kv1 potassium channel complex-subtyped autoimmune painful polyneuropathy.
abstract: 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.
  
  
  
  Clinicopathologic features were studied in subtyped VGKC-autoantibody-seropositive patients who had undergone nerve biopsies.
  
  
  
  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.
  
  
  
  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: Peripheral Neuropathy Research Laboratory, Mayo Clinic, Rochester, Minnesota, USA.
authors: Rajat
authors: R
authors: Lahoria
authors: Neuroimmunology Laboratory, Mayo Clinic, 200 First Street SW, Rochester, Minnesota, 55905, USA.
authors: Sean J
authors: SJ
authors: Pittock
authors: Neuroimmunology Laboratory, Mayo Clinic, 200 First Street SW, Rochester, Minnesota, 55905, USA.
authors: Avi
authors: A
authors: Gadoth
authors: Peripheral Neuropathy Research Laboratory, Mayo Clinic, Rochester, Minnesota, USA.
authors: Janean K
authors: JK
authors: Engelstad
authors: Neuroimmunology Laboratory, Mayo Clinic, 200 First Street SW, Rochester, Minnesota, 55905, USA.
authors: Vanda A
authors: VA
authors: Lennon
authors: Peripheral Neuropathy Research Laboratory, Mayo Clinic, Rochester, Minnesota, USA.|Neuroimmunology Laboratory, Mayo Clinic, 200 First Street SW, Rochester, Minnesota, 55905, USA.
authors: Christopher J
authors: CJ
authors: Klein
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001323:Autoantibodies / Q000097:blood*; D005260:Female; D020275:Guillain-Barre Syndrome / Q000097:blood* / Q000150:complications* / Q000473:pathology / Q000628:therapy; D006801:Humans; D016756:Immunoglobulins, Intravenous / Q000627:therapeutic use; D047908:Intracellular Signaling Peptides and Proteins; D051657:KCNQ1 Potassium Channel / Q000276:immunology*; D008297:Male; D008565:Membrane Proteins / Q000276:immunology; D046529:Microscopy, Electron, Transmission; D008875:Middle Aged; D009419:Nerve Tissue Proteins / Q000276:immunology; D009431:Neural Conduction / Q000502:physiology; D010146:Pain / Q000097:blood / Q000188:drug therapy / Q000209:etiology* / Q000473:pathology; D011506:Proteins / Q000276:immunology; D012720:Severity of Illness Index; D013497:Sural Nerve / Q000473:pathology / Q000648:ultrastructure
chemical_list: D001323:Autoantibodies; C403049:CNTNAP2 protein, human; D016756:Immunoglobulins, Intravenous; D047908:Intracellular Signaling Peptides and Proteins; D051657:KCNQ1 Potassium Channel; C116499:LGI1 protein, human; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D011506:Proteins
keywords: channelopathy; immunotherapy; nerve biopsy; pain; voltage-gated potassium antibody