HMGB1 and retinitis pigmentosa 1: High-mobility group box-1 (HMGB1) is an intracellular DNA-binding protein that regulates transcription activity; however, it is released into the extracellular space under stressed conditions that cause necrosis, and it mediates inflammatory signals.19–21 To further investigate the involvement of necrotic cell death in RP, we examined the changes of HMGB1 release into the vitreous of the RP patients.