As the apoptosis of endothelial cells contributes to the pathogenesis of SSc as one of the initial steps,31 32 we also observed the significantly increased cell counts of apoptotic PRMT5-positive endothelial cells in the dermis of patients with SSc (online supplemental figure S8), indicating the potential underlying mechanism that PRMT5 may be exposed from apoptotic endothelial cells, triggering autoimmune response subsequently. Here, PRMT5 is linked to systemic sclerosis.