2022 Volume 27 Issue 1 Pages 52-
Infections often trigger autoimmune diseases in children. Anti-NMDA receptor encephalitis（NMDARE）is an autoimmune encephalitis which is often associated with ovarian teratomas in young women, Immune cells target tumor-expressed NMDA receptors and produce anti-NMDA receptor antibodies. However, infection is another trigger for the development of NMDARE, and it is speculated that these infections may cause the infiltration of both autoantibodies and immune cells to the central nervous system. The most commonly studied prior infection is herpes simplex encephalitis（HSE）；27% of HSE cases are followed by autoimmune encephalitis, most frequently NMDARE；NMDARE usually develops within 3 months from the onset of HSE and presents with somewhat different symptoms than the initial HSE, including involuntary movements. Patients younger than 4 years tend to have a shorter interval between HSE and NMDARE and a poorer prognosis. Anti-NMDA receptor antibodies are usually negative at the onset of HSE and become positive thereafter, suggesting that infection triggers the production of autoantibodies. Japanese encephalitis is also known to induce NMDARE, and treatment of post-HSE NMDARE is similar to conventional NMDARE. Approximately half of all NMDARE cases are children and the clinical picture of NMDARE in children is different from that in adults. Probable diagnostic criteria for NMDARE have been proposed based on clinical symptoms and general laboratory findings without depending on the results of antineuronal antibodies. The probable NMDARE criteria are also applicable to children.
