AQP4 and autoimmune encephalitis: Immunological testing revealed positive serum anti-SS-A, anti-Ro-52, and anti-M2 antibodies, while serum ANA, ANCA, autoimmune encephalitis antibodies, and demyelination-related antibodies (aquaporin-4 [AQP4], Myelin Oligodendrocyte Glycoprotein [MOG], and glial fibrillary acidic protein [GFAP]) were negative.