After subdividing the patients, the encephalitis patients had significantly higher concentrations of serum NFL than those with meningitis (155.6 pg/mL; 65.1–403.8 pg/mL versus 8.1 pg/mL; 3.5–21.3 pg/mL, p < 0.001), Ramsay Hunt syndrome (30.4 pg/mL; 7.4–114.4 pg/mL, p = 0.043), and the healthy controls (9 pg/mL; 5.9–14.7 pg/mL, p < 0.001) (Fig. 2b). Here, NEFL is linked to infectious meningitis.