During uveitis, Müller glial cells alter their characteristics to become reactive glial cells, leading to breakdown of the blood-retinal barrier with leukocyte infiltration into the vitreous cavity and leukocyte adhesion to the retinal vessels (Bhattacherjee et al., 1983), and it can be recognized by GFAP upregulation (Eisenfeld et al., 1984). The gene discussed is GFAP; the disease is uveitis.