AQP4 and acrodermatitis enteropathica: CSF and serum tests for autoimmune encephalitis (AE) antibodies, including myelin oligodendrocyte glycoprotein (MOG), glial fibrillary acidic protein (GFAP), and aquaporin-4 (AQP4) antibodies, serum tuberculosis (TB) antibodies, CSF acid-fast staining, and ink staining for Cryptococcus were all negative.