To identify the differentially expressed exosomal miRNAs derived from CSF, we performed miRNA profiling of purified exosomes isolated from CSF fluid of 13 patients with anti-NMDA receptor encephalitis, 11 patients with anti- GABAB receptor encephalitis, 9 patients with anti-LGI1 encephalitis, 8 patients with anti-CASPR2 encephalitis, 9 patients with HSE, and control subjects (n = 12), using the NanoString Technology platform. The gene discussed is CNTNAP2; the disease is herpes simplex encephalitis.