Acute encephalitis is an inflammatory brain disease with a complex differential diagnosis associated with appreciable morbidity, mortality, and costs. Infectious agents, particularly viruses, were traditionally considered the predominant causes. The discovery of neuronal cell-surface autoantibodies (NSAbs) has helped identify a subgroup of patients with encephalitis who often respond well to immunotherapy. Autoantibodies were not mentioned in a 2007 retrospective study on the causes of acute encephalitis, but 3 years later the same authors reported that 8% of cases were associated with autoantibodies against the voltage-gated potassium channel complex and the NMDA receptor (NMDAR). In subsequent years, several new targets have been reported in patients with encephalitis. In approximate order of decreasing frequency, these include the NMDAR, leucine-rich, glioma inactivated 1 (LGI1), gamma aminobutyric acid receptor B (GABABR), contactin-associated protein-like 2 (CASPR2), gamma aminobutyric acid receptor A (GABAAR), dipeptidyl aminopeptidase-like protein 6 (DPPX), metabotropic glutamate receptor 5 (mGluR5), and the dopamine 2 receptor (D2R).