NEFL and HIV infectious disease: CSF levels of the glial markers neopterin and sTREM2, and the astroglial marker YKL-40, correlate with CSF NfL, supporting the role of neuroinflammation in axonal injury during HIV infection (Hagberg et al. 2000; Hermansson et al. 2019; Gisslén et al. 2019; Gisslen et al. 2021).