Thus, we could not confirm previous reports on altered NFH, NFL or NAA levels in patients with CIS who converted to definite MS compared with non-converters.6,33 In our CIS cohort, we could also not find any differences for NFH, NFL and NAA comparing patients whose CSF was obtained in remission compared with acute patients, as reported previously.6,11,32. Here, NEFH is linked to myeloid sarcoma.