Patients with anti-LGI1 encephalitis presenting with cognitive impairments (n = 18) had significantly higher CSF CHI3L1 levels than those without cognitive impairment symptoms (n = 12, p = 0.022, Figure 2A), but these two groups had similar serum CHI3L1 levels (Figure 2B). This evidence concerns the gene CHI3L1 and encephalitis.