LRP4 antibodies

Indication

Suspected Myasthenia gravis.

Method

Indirect immunofluerescens (IIF) using cells transfected with LRP4.

Response

The result is given as negative or positive. Follow up samples can be requested to be titrated. 

Interpretation

Lipoprotein receptor-related protein-4 (LRP4) is a member of a family of membrane proteins with key roles in neuronal and synaptic development. LRP4 and muscle-specific kinase (MuSK) forms together with acetylcholine receptor (AChR) clusters in the neuromuscular Junktion (NMJ) and in these clusters depolarization occurs in response to nerve stimulation. Antibodies against LRP4 have been identified in Myasthenia Gravis patients who are sero-negative for both AChR and MuSK antibodies. The frequency of LRP4 antibodies was 18.7% in a large international study (635 patients), but with a large variation between different populations (7 to 32.7%). The variation could not be linked to any geographic distribution. LRP4 antibody-positive patients respond to similar treatment strategy as AChR-antibody-positive patients, in contrast to MuSK antibody-positive patients. There are also double-positive MG patients who are positive for antibodies against AChR/LRP4 or double positive against MuSK/LRP4. Double-positive patients generally have more severe symptoms.

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References

Zouvelou V, Zisimopoulou P Rentzos M, Karandreas N, Evangelakou P Stamboulis E, Tzartos SJ Double seronegative myasthenia gravis with anti-LRP 4 antibodies. Neuromuscul Disord. 2013 Jul, 23 (7):568-70. PMID: 23768983

Zisimopoulou P. et al. A Comprehensive Analysis of the epidemiology and clinical characteristics of the anti-LRP4 in myasthenia gravis, Journal of Autoimmunity (2013), http://dx.doi.org/10.1016/j.jaut.2013.12.004 . PMID: 24373505

Berrih-Aknin S Frenkian-Cuvelier M, Eymard B. Diagnostic and Clinical Classification of autoimmune myasthenia gravis. J Autoimmun. 2014 Feb-Mar; 48-49:143-8. PMID: 24530233

Pevzner A, Schoser B, Peters K, Cosma NC, Karakatsani A, Schalke B, Melms A, Kröger S. Anti-LRP4 autoantibodies in AChR-and MuSK-antibody-negative myasthenia gravis. J Neurol. 2012 Mar; 259(3):427-35. PMID: 21814823

Clinical studies