Antibody Levels Correlate With Creatine Kinase Levels and Strength in Anti-3-Hydroxy-3-Methylglutaryl-Coenzyme A Reductase-Associated Autoimmune Myopathy

作者：Werner Jessie L; Christopher Stine Lisa; Ghazarian Sharon R; Pak Katherine S; Kus Jordan E; Daya Natalie R; Lloyd Thomas E; Mammen Andrew L^*

来源：Arthritis and Rheumatism, 2012, 64(12): 4087-4093.

DOI：10.1002/art.34673

Objective. Autoantibodies recognizing 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR) are found in patients with statin-associated immunemediated necrotizing myopathy and, less commonly, in statin-unexposed patients with autoimmune myopathy. The main objective of this study was to define the association of anti-HMGCR antibody levels with disease activity.
Methods. Anti-HMGCR levels, creatine kinase (CK) levels, and strength were assessed in anti-HMGCR-positive patients. Associations of antibody level with CK level and strength at visit 1 were analyzed in 55 patients, 40 of whom were exposed to statins. In 12 statin-exposed and 5 statin-unexposed patients with serum from 5 serial visits, the evolution of antibody levels, CK levels, and strength was investigated.
Results. Antibody levels were associated with CK levels (P < 0.001), arm strength (P < 0.05), and leg strength (P < 0.05) at visit 1, but these associations were only significant among statin-exposed patients in stratified analyses. With immunosuppressive treatment over 26.2 +/- 12.6 months (mean +/- SD), antibody levels declined (P < 0.05) and arm abduction strength improved (P < 0.05) in the 17 patients followed up longitudinally. The separate analysis showed that statin-exposed patients developed decreased antibody levels (P < 0.01), decreased CK levels (P < 0.001), improved arm strength (P < 0.05), and improved hip flexion strength (P < 0.05) with treatment. Anti-HMGCR antibody levels did not normalize in any patient.
Conclusion. In the entire cohort, initial anti-HMGCR levels correlated with indicators of disease activity; with immunosuppressive treatment, antibody levels declined and arm strength improved. Statin-exposed patients had significant improvements in CK levels and strength whereas statin-unexposed patients did not, suggesting a phenotypic difference between statin-exposed and statin-unexposed anti-HMGCR-positive patients.

• 出版日期2012-12