Neurofilament light chain and glial fibrillary acidic protein as biomarkers of peripheral nervous system involvement in multiple sclerosis: diagnostic and prognostic evaluation.

BACKGROUND: Multiple sclerosis is a chronic demyelinating disease of the central nervous system caused by an immune-mediated inflammatory process. Its aetiology remains unclear, and numerous pathogenetic theories have been proposed. The diversity of clinical manifestations and the lack of reliable biomarkers make diagnosis challenging. Serum neurofilament light chain (NfL) and glial fibrillary acidic protein (GFAP) have been investigated as potential biomarkers for disease progression and response to disease-modifying therapies; however, their specificity and sensitivity remain variable, particularly in the presence of other conditions associated with neuronal damage and neurodegeneration.

METHODS: This retrospective study analysed serum NfL and GFAP levels in 149 patients with multiple sclerosis and 40 healthy controls. Additionally, the association between the two biomarkers was evaluated in patients with and without polyneuropathy to assess their reliability and prognostic value for disease severity and progression.

RESULTS: Serum NfL was found to be a reliable marker of disease activity and progression. In contrast, GFAP demonstrated limited specificity and was not suitable as a single, independent biomarker. The presence of co-existing polyneuropathy influenced biomarker levels and complicated their interpretation.

CONCLUSION: Serum NfL shows promise as a reliable biomarker for monitoring disease activity and progression in multiple sclerosis. However, GFAP should not be used independently due to its limited specificity. Co-existing polyneuropathy may further reduce the reliability of these biomarkers, highlighting potential diagnostic challenges in clinical practice.