Plasma periaxin is an ultrasensitive biomarker that differentiates peripheral demyelinating neuropathies from CNS diseases. A 2025 Brain study measured periaxin levels in patients with CIDP, Guillain-Barré syndrome (GBS), Charcot-Marie-Tooth disease (CMT) and controls. Levels were significantly elevated in CIDP, GBS and CMT, but not in CNS disease or healthy controls. In CIDP, periaxin distinguished active from inactive disease and decreased after intravenous immunoglobulin.
High periaxin predicted clinical worsening at one year with 100 % sensitivity and 72 % specificity (cut off 262 pg/ml; AUC 0.81). In GBS, periaxin and the ratio of periaxin to neurofilament light chain discriminated demyelinating AIDP from axonal AMAN with high accuracy (sensitivity 100 %, specificity 86 %). Periaxin levels peaked 2–3 weeks after GBS onset and declined thereafter. In vitro, periaxin release was higher after immune mediated demyelination than axonal injury. These findings suggest plasma periaxin as a promising fluid biomarker for peripheral nerve demyelination.
Key Points:
- Plasma periaxin is elevated specifically in peripheral demyelinating neuropathies (CIDP, GBS, CMT) but not in CNS disease or healthy controls
- In CIDP, periaxin tracked disease activity distinguishing active from inactive disease, decreasing after IVIg treatment, and predicting clinical worsening at one year with 100% sensitivity and 72% specificity
- In GBS, periaxin accurately discriminated demyelinating AIDP from axonal AMAN
References:
Bellanti R, Keh RYS, Keddie S, Chou MKL, Misheva M, Smyth D, et al. Plasma periaxin is a biomarker of
peripheral nerve demyelination. Brain. 2025 Jun 20;148(12):4448–60. DOI: 10.1093/brain/awaf234.
Publish on behalf of the Scientific Panel on Neuropathies.