SERPINF1 and myasthenia gravis: While pigment epithelium-derived factor (PEDF) locates in the interphotoreceptor matrix and is believed to be a neuroprotective factor released by RPE (Polato and Becerra, 2016; Pagan-Mercado and Becerra, 2019), down-regulation of PEDF expression in MG resulted in increases of VEGF and TNF-α secretion, indicating PEDF an endogenous anti-inflammatory factor in MG (Zhang et al., 2006).