Brady S, Squier W, Sewry C, et al. A retrospective cohort study identifying the principal pathological features useful in the diagnosis of inclusion body myositis. BMJ Open 2014;4:e004552. During the production process some errors to the values in table 2 were inadvertently introduced, specifically to the values in the rows entitled ‘MHC class I upregulation’ and ‘Strong MHC class I upregulation’, and columns ‘IBM - RV n (%)’, ‘IBM - RV vs PM&DM Sensitivity’ and ‘IBM+RV vs IBM - RV p value.’ The correct table is provided below.