While IgG4 was the predominant subclass of the here described CASPR2 mAbs – in line with serum findings of CASPR2 encephalitis patients (Van Sonderen et al., 2016) – CSF-derived mAbs were mainly IgG2 in patients with LGI1 encephalitis and IgG1 in NMDAR and GABAAR encephalitis (Kornau et al., 2020; Kreye et al., 2021, 2016). The gene discussed is CNTNAP2; the disease is viral encephalitis.