LGI1 and viral encephalitis: This mechanism, however, seems at odds with the observation that almost all patients with anti-LGI1 encephalitis harbor anti-LGI1-immunoglobulin G-(IgG-)4 antibodies [1, 3, 14, 31], so that anti-LGI1 encephalitis has been subsumed under the group of IgG4-mediated neurological autoimmune disorders [19].