Biomarkers in inflammatory neuropathies: where are we?

Purpose of review: This review provides an overview of recent advances in fluid-based biomarker research in inflammatory neuropathies, with a particular focus on disease activity monitoring. It explores challenges along the biomarker pipeline and outlines the stage of development of emerging disease activity biomarkers.

Recent findings: Numerous biomarkers have recently been investigated for diagnostic, prognostic and monitoring purposes. Neurofilament light chain has been studied furthest but its clinical utility is limited in most patients. Other recent work has identified new biomarkers reflecting nerve damage, including peripherin, periaxin and Contactin-1. Additionally, potential immunological markers of disease activity have been explored, some more generic (such as chemokines) and others highly disease specific (such as autoantibody titers). Additional candidates have emerged through unbiased high-throughput discovery studies.

Summary: Current fluid-based biomarkers can be grouped into nerve damage or immunological biomarkers. Most have not proceeded beyond discovery and validation stages, except for Neurofilament Light Chain. Biomarker development is challenging due to the inherent rarity and heterogeneity of inflammatory neuropathies, and, in the case of disease activity biomarkers, a lack of reference standard.