Complement profiling of sural nerves in chronic-inflammatory demyelinating polyneuropathy.

Area of Science:

• Neurology
• Immunology
• Pathology

Background:

• Chronic-inflammatory demyelinating polyneuropathy (CIDP) is a rare, disabling immune-mediated disorder.
• The role of the complement system in CIDP pathogenesis is not well understood.
• Understanding complement's role is crucial given the development of complement-targeted treatments.

Purpose of the Study:

• To investigate the involvement of the complement system in the sural nerve pathology of CIDP patients.
• To correlate complement deposition with clinical disease severity and immune cell infiltration.

Main Methods:

• Sural nerve biopsies from 55 CIDP patients, 2 non-diseased controls (NDCs), and 8 patients with hereditary neuropathy (HN) or idiopathic axonal neuropathy (IPN) were analyzed.
• Histopathology, gene expression, and proteomics were employed to assess complement deposition and related molecular changes.
• Immunohistochemistry was used to quantify CD8+ T cells and CD68+ macrophages.

Main Results:

• Prominent deposition of terminal complement complex C5b-9 was observed in endoneurial capillaries of 94% of CIDP patients.
• Significant complement deposition correlated with a progressive disease course and infiltration of CD8+ T cells and CD68+ macrophages.
• The extent of immune cell infiltration correlated with clinical disease severity (INCAT score, p < 0.001).

Conclusions:

• This study demonstrates significant complement involvement in CIDP nerve pathology, supporting the concept of complement-mediated demyelination.
• The findings suggest that targeting the complement system could be a promising therapeutic strategy for a subset of CIDP patients.
• Further research is needed to elucidate the functional role of complement in CIDP progression and optimize patient management.