AQP4 and viral encephalitis: PubMed was searched for the terms “NMDAR” and “MS,” “NMDAR” and “NMOSD,” “NMDAR” and “MOG,” “NMDAR” and “AQP4,” “NMDAR” and “demyelination,” “MS” and “demyelination,” “AQP4” and “NMOSD,” and “MOG” and “encephalitis” from inception to July 2021 to identify NMDARe cases overlapped with MS, AQP4-Ab-positive NMOSD, and MOGAD.