Live cell-based assay confirmed the co-localization of surface-expressed NR1 with isotype-specific Ig binding, and the expected loss of binding after depletion of specific antibody isotypes (Fig. 1A).14 NR1-IgA and NR1-IgM autoantibodies were detected in 77 (27%) and 122 (43%) of the 285 NMDAR-antibody encephalitis sera, respectively, and in only 9/508 (1.7%) and 7/508 (1.3%) samples from disease and healthy control sera (both P < 0.0001, two-tailed Fisher’s exact test; Fig. 1B). Here, CD40LG is linked to encephalitis.