Objective: We aimed to establish the prevalence and clinical associations of anti-HMG-CoA-reductase (anti-HMGCR) in a large UK cohort with juvenile myositis.
Methods: There were 381 patients investigated for anti-HMGCR using ELISA.
Results: Anti-HMGCR autoantibodies were detected in 4 patients (1%). These children had no or minimal rash and significant muscle disease. Muscle biopsies were considered distinctive, with widespread variation in fiber size, necrotic fibers, and chronic inflammatory cell infiltrates; all had prolonged elevation of creatine kinase and all ultimately received biologic therapies.
Conclusion: Anti-HMGCR in UK children with myositis are associated with severe disease that is poorly responsive to standard treatment.
Keywords: AUTOANTIBODIES; PEDIATRIC DERMATOMYOSITIS/POLYMYOSITIS; PEDIATRIC RHEUMATIC DISEASES; PROGNOSIS.