Referenced in: none

Automatically associated channels: ClC4

Title: Antibodies to active zone protein ERC1 in Lambert-Eaton myasthenic syndrome.

Authors: Maartje G Huijbers, Alexander F Lipka, Marko Potman, Paul J Hensbergen, Maarten J Titulaer, Erik H Niks, Silvère M van der Maarel, Rinse Klooster, Jan J Verschuuren

Journal, date & volume: Hum. Immunol., 2013 Jul , 74, 849-51

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/23583364

Abstract
Lambert-Eaton myasthenic syndrome (LEMS) is characterized by fluctuating muscle weakness and autonomic dysfunction. In 90% of the LEMS patients the disease is associated with auto-antibodies against the voltage-gated calcium channels (VGCC). Several auto-immune responses against other antigenic targets have been described to (co)-occur in LEMS patients. To identify new LEMS associated small cell lung cancer (SCLC) markers immunoprecipitation with a SCLC cell line was performed. We discovered strong immunoreactivity against the 120 kDa large ERC1 protein in one tumor-negative VGCC-positive LEMS patient. A recombinant ELISA assay and a cellular assay expressing GFP-tagged full length ERC1 were used to confirm the presence of auto-antibodies against ERC1 in this patient. Additional testing of 58 LEMS patients including 9 VGCC auto-antibody negative LEMS patients, 48 myasthenia gravis patients, 84 control patients with other diseases and 12 healthy controls revealed no other cases. ERC1 is therefore a new, but rare, antigen in LEMS.