Comparison of some neuroinflammatory biomarkers in acute and chronic inflammatory demyelinating polyneuropathies

The present study aimed to determine the levels of certain biomarkers associated with neuronal inflammation, including neurofilament light chain (NfL), neurofilament heavy chain (NfH), sphingomyelin (SM), glial fibrillary acidic protein (GFAP), and brain-derived neurotrophic factor (BDNF), in cerebrospinal fluid (CSF) samples obtained from patients diagnosed with acute or chronic inflammatory demyelinating polyneuropathy (AIDP or CIDP) who presented to the Neurology Clinic of BAİBÜ Education and Research Hospital. Additionally, the study sought to investigate the relationships between these biomarker levels and various demographic factors, blood parameters, and electrophysiological (EMG) data. Medical records of patients who presented to the Neurology Clinic of BAİBÜ Education and Research Hospital between December 2023 and October 2024 and underwent lumbar puncture (LP) for diagnostic purposes were retrospectively reviewed. CSF samples and clinical data of 20 AIDP patients, 18 CIDP patients, and 15 patients with pseudotumor cerebri (PTS), included as the unhealthy control group, were analyzed. The CSF levels of NfL, NfH, GFAP, SM, and BDNF in the AIDP group were significantly higher than those in the PTS group (p<0.05). In the CIDP group, CSF NfL, GFAP, and SM levels were significantly elevated compared to the PTS group (p<0.05), while no significant difference was observed in CSF NfH and BDNF levels between the CIDP and PTS groups. Furthermore, the AIDP group had significantly higher levels of NfH and BDNF in CSF compared to the CIDP group (p<0.05). These findings suggest that in AIDP and CIDP patients, the elevation of CSF NfL, NfH, and GFAP levels may be associated with secondary proximal axonal damage. Additionally, SM could serve as an indicator of myelin breakdown and remodeling, while the compensatory effect of BDNF may support remyelination. In conclusion, these five biomarkers may represent promising targets for the early diagnosis and differential diagnosis of AIDP and CIDP.