Clinical-pathologic correlations in voltage-gated Kv1 potassium channel complex-subtyped autoimmune painful polyneuropathy

Rajat Lahoria, Sean J Pittock, Avi Gadoth, Janean K. Engelstad, Vanda A Lennon, Christopher Jon Klein

Research output: Contribution to journalArticle

11 Scopus citations

Abstract

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.

Original languageEnglish (US)
Pages (from-to)520-525
Number of pages6
JournalMuscle and Nerve
Volume55
Issue number4
DOIs
StatePublished - Apr 1 2017

Keywords

  • channelopathy
  • immunotherapy
  • nerve biopsy
  • pain
  • voltage-gated potassium antibody

ASJC Scopus subject areas

  • Physiology
  • Clinical Neurology
  • Cellular and Molecular Neuroscience
  • Physiology (medical)

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