HMGB1 and inclusion body myositis: Sarcoplasmic HMGB1 expression modestly negatively correlated with symptom duration in IMNM patients (rs −0.38, p < 0.01, n = 50) but trended toward a positive correlation in IBM patients (rs 0.62, p = 0.07, n = 9), likely reflecting that different processes are responsible for HMGB1 expression in these diseases.