MOG-Encephalitis is the Most Prevalent Autoimmune Encephalitis in Children: MERIN Study Data on Encephalitis.

Encephalitis in children is a serious inflammatory brain disease caused by infectious or autoimmune-mediated processes. The frequency of autoimmune variants in pediatric populations is not entirely clear.To study the frequency of myelin oligodendrocyte glycoprotein (MOG) antibody (ab)-mediated autoimmune encephalitis (AE) in children included in the Meningitis/Encephalitis register of Lower Saxony (MERIN).Medical records of 1,341 children treated between 2011 and 2020 in two large children's hospitals participating in a prospective study on encephalitis (MERIN) were reviewed. Children meeting diagnostic criteria for possible AE were finally included if serum samples and informed re-consent were available. Children with pathogen-mediated encephalitis were also included as controls. All available serum samples were tested for MOG- and anti-N-methyl-D-aspartate receptor (NMDAR) antibodies (abs) using cell- and tissue-based assay (TBA).We included 55 children of whom 16 had pathogen-associated meningoencephalitis. Thirty-nine out of fifty-five children were classified as possible AE and 3/39 fulfilled the criteria for MOG ab-associated disease (MOGAD). No patients' sera harbored NMDAR abs. However, 5/39 patients fulfilled the criteria for probable, auto-ab-negative AE.In line with recent research our study suggests that ab-mediated AE and probable ab-negative AE are rare in children. The existing criteria seem suitable for identifying patients with AE but should include the testing of serum MOG abs. Further yet unknown abs may play a role in children with AE.