NEFL and viral encephalitis: CNS concentration of S100B is closely linked to treatment response, disease severity and prognosis. The level of CSF-Nfl is closely related to prognosis of both anti-NMDAR and anti-LGl1 encephalitis. Patient has either of these 2 types of AE accompanied by CSF-Nfl elevation manifested poor diagnosis and prognosis. The level of Nfl is also closely related to disease severity.