Lambert–Eaton myasthenic syndrome differential reactivity of tumor versus non-tumor patients to subunits of the voltage-gated calcium channel

Abstract Objective Lambert–Eaton myasthenic syndrome (LEMS) is an autoimmune disease in which the transmission across the neuromuscular junction is disturbed by autoantibodies directed against the presynaptic P/Q-type voltage-gated calcium channels (VGCC). LEMS is paraneoplastic (T-LEMS) in about 60...

Full description

Saved in:

Bibliographic Details
Published in:	Journal of neuroimmunology 2008-11, Vol.204 (1), p.136-139
Main Authors:	Pellkofer, Hannah L, Armbruster, Lena, Krumbholz, Markus, Titulaer, Maarten J, Verschuuren, Jan J, Schumm, Friedrich, Voltz, Raymond
Format:	Article
Language:	eng
Subjects:	Allergy and Immunology Antibody Autoantibodies - blood Calcium Channels, N-Type - immunology Female Humans Lambert-Eaton Myasthenic Syndrome - blood Lambert-Eaton Myasthenic Syndrome - complications LEMS Lung Neoplasms - blood Male Middle Aged Neurology Paraneoplastic Protein Structure, Tertiary Small Cell Lung Carcinoma - blood VGCC
Online Access:	Get full text
Tags:	Add Tag No Tags, Be the first to tag this record!

Description
Summary:	Abstract Objective Lambert–Eaton myasthenic syndrome (LEMS) is an autoimmune disease in which the transmission across the neuromuscular junction is disturbed by autoantibodies directed against the presynaptic P/Q-type voltage-gated calcium channels (VGCC). LEMS is paraneoplastic (T-LEMS) in about 60% of patients mostly associated with a small cellular lung carcinoma (SCLC), but occurs spontaneously without a tumor in 40% (NT-LEMS). In most cases neurologic symptoms appear before tumor diagnosis, but there is as yet no clear specific serologic marker to distinguish between NT- and T-LEMS. Methods To see whether antibodies from patients with NT- and T-LEMS differentially recognize antigenic sites of the alpha 1A subunit of P/Q-type VGCC, we studied serum samples from 22 T-LEMS and 24 NT-LEMS patients. Sera reactivity was tested by Western blot analysis to recombinant proteins corresponding to the extracellular S5–S6 linker region of three out of four domains forming the alpha 1 subunit of P/Q-type VGCC. Results Sera from 9/24 (37,5%) NT-LEMS patients, but only 1/22 (4,6%) T-LEMS patients recognized domain IV ( p = 0,011). Seroreactivity to domains I and III was similar for NT-LEMS and T-LEMS patients (domain I: 8%/14%; domain III: 46%/41%, not significant). Conclusions These data suggest that an antibody response to domain IV is more common in LEMS without tumor than in paraneoplastic LEMS. This may have implications for diagnostic workup in LEMS patients without previously established diagnosis of a tumor. Additionally this could point towards a differential autoimmune pathogenesis between T-LEMS and NT-LEMS.
ISSN:	0165-5728 1872-8421