Background: .Serum neurofilament light chain (NFL) has been the subject of intensive research as a potential biomarker of treatment response as well as prognosis among multiple sclerosis cases because it can reflect disease activity in the clinical follow up of these patients and measured in serum.

Aim: to assess serum NFL in MS cases and its relation with disease severity & magnetic resonance imaging(MRI) finding in these patients.

Subjects and methods: Fifty MS patients were included in a case-control research conducted at three hospitals in Egypt: Zagazig University Hospital, AL Mabara Hospital for Health Insurance in Zagazig, and Mansoura New General Hospital. Diagnosis of MS was done according to Modified McDonald criteria. Patients were divided into 25 patients with relapsing–remitting multiple sclerosis (RRMS), 18 patients with secondary progressive multiple sclerosis (SPMS), 7 patients with primary progressive multiple sclerosis (PPMS) & 25 sex and age matched healthy controls.

Results: There is a statistical significance increase serum NFL among cases than control group and a significance increase of Serum NFL among RRMS than SPMS and PPMS groups.

Conclusion: The results showed that NFL levels were associated with disease severity as assessed by Expanded Disability Status Scale (EDSS) as well as MRI findings in MS patients.