S100A4 and dermatomyositis: Patients with PM had higher serum levels of S100A4 compared to healthy controls (41.6 (24.2 to 123.1) versus 23.8 (14.5 to 33.7) ng/ml, P <0.001) or to patients with DM (to 26.7 (11.3 to 47.5) ng/ml, P <0.05).