They were diagnosed with MOG antibody-associated encephalitis due to M. pneumoniae infections, and the treatment consisted of intravenous immunoglobulin (IVIG, 2 g/kg over 2 d), glucocorticoid (intravenous injection of methylprednisolone at 20 mg/kg × 5 d, followed by oral prednisone at 2 mg/kg/d with tapering decrease in dose), and erythromycin (10 mg/kg once every 12h × 7-14d). Here, MOG is linked to viral encephalitis.