NEFL and myeloid sarcoma: MS patients in the 2nd and 3rd tertiles of the serum NfL values at baseline had a larger HR for developing an EDSS ≥ 6 during follow up (2nd tertile: HR = 2.1 (95% CI 0.5–8.3), p = 0.307; 3rd tertile: HR = 3.6 (95% CI 1.0–13.4), p = 0.054, data not shown).