HSP90B2P and rheumatoid arthritis: Autoantibodies and CD4+ T cells involved in the pathogenesis of RA are observed in patients with POAG,15,16 and enhanced expression of heat shock protein (HSP) is also commonly observed.3 Furthermore, etanercept, a tumor necrosis factor–α inhibitor used to control RA progression, reduced retinal ganglion cell (RGC) loss by approximately 50% in a rat glaucoma model.17 Given that the role of autoimmunity as a cause of various neurodegenerative diseases has been elucidated,18 the possibility of autoimmunity causing glaucoma cannot be ignored.19