8 (serum titer 1:160), 14 (1:320), 19 (1:160) and 20 (1:160)] did not fulfill these criteria, but the LGI1 antibody positivity was corroborated by the IgG4 positivity, which is unlikely to occur by chance since the IgG4 subclass is estimated as making up for only 5% of the total amount of IgG [23]; more importantly, no better diagnosis than anti-LGI1 encephalitis could be made after a full diagnostic work-up (nos. Here, LGI1 is linked to viral encephalitis.