Pro-inflammatory S100A11 is elevated in inflammatory myopathies and reflects disease activity and extramuscular manifestations in myositis

Abstract Background S100A11 (calgizzarin), a member of the S100 family, is associated with oncogenesis, inflammation and myocardial damage. Our aim was to analyse S100A11 in idiopathic inflammatory myopathies (IIMs) and its association with disease activity features and cancer development. Methods S100A11 in muscle was determined by immunohistochemistry in polymyositis (PM), dermatomyositis (DM), myasthenia gravis (MG) and in subjects without autoimmune inflammatory disease (HC). S100A11 in plasma was measured in 110 patients with IIMs (PM, DM, and cancer associated myositis (CAM) patients) and in 42 HC. Disease activity was assessed by myositis disease activity assessment (MYOACT), muscle enzymes and C-reactive protein (CRP) were measured by routine laboratory techniques; autoantibodies by immunoprecipitation or by immunoblot. Results We observed an accumulation of S100A11 in the cytoplasm of regenerating and necrotizing muscle fibres of PM and DM patients. S100A11 was increased in plasma of all myositis patients compared to HC (3.8 (1.5–16.8) vs 2.8 (1.7–11.2) ng/ml, p = 0.011) and in DM and CAM patients compared to HC (4.0 (2.2–14.9) and 4.5 (1.5–9.1) vs 2.8 (1.7–11.2) ng/ml, p  Conclusions We show for a first time a potential implication of S100A11 in the local inflammatory and tissue remodelling processes in myositis and an association of circulating S100A11 with disease activity and extra muscular manifestations in DM.