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  • Anti-HMGCR autoantibodies in European patients with autoimmune necrotizing myopathies: inconstant exposure to statin.

Anti-HMGCR autoantibodies in European patients with autoimmune necrotizing myopathies: inconstant exposure to statin.

Medicine (2014-05-07)
Yves Allenbach, Laurent Drouot, Aude Rigolet, Jean Luc Charuel, Fabienne Jouen, Norma B Romero, Thierry Maisonobe, Odile Dubourg, Anthony Behin, Pascal Laforet, Tania Stojkovic, Bruno Eymard, Nathalie Costedoat-Chalumeau, Emmanuelle Campana-Salort, Anne Tournadre, Lucile Musset, Brigitte Bader-Meunier, Isabelle Kone-Paut, Jean Sibilia, Laurent Servais, Olivier Fain, Claire Larroche, Elisabeth Diot, Benjamin Terrier, Raphael De Paz, Antoine Dossier, Dominique Menard, Chafika Morati, Marielle Roux, Xavier Ferrer, Jeremie Martinet, Sophie Besnard, Remi Bellance, Patrice Cacoub, Laurent Arnaud, Bernard Grosbois, Serge Herson, Olivier Boyer, Olivier Benveniste
PMID24797170
ABSTRACT

Necrotizing autoimmune myopathy (NAM) is a group of acquired myopathies characterized by prominent myofiber necrosis with little or no muscle inflammation. Recently, researchers identified autoantibodies (aAb) against 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR) in patients with NAM, especially in statin-exposed patients. Here we report what is to our knowledge the first European cohort of patients with NAM.The serum of 206 patients with suspicion of NAM was tested for detection of anti-HMGCR aAb using an addressable laser bead immunoassay. Forty-five patients were found to be anti-HMGCR positive. Their mean age was 48.9 ± 21.9 years and the group was predominantly female (73.3%). Statin exposure was recorded in 44.4% of patients. Almost all patients had a muscular deficit (97.7%), frequently severe (Medical Research Council [MRC] 5 ≤3 in 75.5%). Subacute onset (<6 mo) was noted for most of them (64.4%). Nevertheless, 3 patients (6.6%) had a slowly progressive course over more than 10 years. Except for weight loss (20%), no extramuscular sign was observed. The mean CK level was high (6941 ± 8802 IU/L) and correlated with muscle strength evaluated by manual muscle testing (r = -0.37, p = 0.03). Similarly, anti-HMGCR aAb titers were correlated with muscular strength (r = -0.31; p = 0.03) and CK level (r = 0.45; p = 0.01). Mean duration of treatment was 34.1 ± 40.8 months, and by the end of the study no patient had been able to stop treatment.This study confirms the observation and description of anti-HMGCR aAb associated with NAM. The majority of patients were statin naive and needed prolonged treatments. Some patients had a dystrophic-like presentation. Anti-HMGR aAb titers correlated with CK levels and muscle strength, suggesting their pathogenic role.