Increased CSF C4d in demyelinating neuropathy indicates the radicular involvement

Area of Science:

• Neurology
• Immunology
• Biochemistry

Background:

• Chronic inflammatory demyelinating polyneuropathy (CIDP) and Guillain-Barré syndrome (GBS) are immune-mediated neuropathies.
• The complement system, particularly C4d, plays a role in inflammatory and immune processes.
• Understanding the origin and significance of C4d in the cerebrospinal fluid (CSF) is crucial for diagnosing neuropathies.

Purpose of the Study:

• To measure plasma and CSF levels of C4d and circulating immune complexes (CIC) to C1q.
• To investigate the correlation between CSF C4d levels and demyelinating polyneuropathies.
• To determine if CSF C4d can serve as an indicator of radicular involvement.

Main Methods:

• Measurement of plasma and CSF C4d and CIC to C1q in 12 patients with CIDP and GBS.
• Comparison of CSF C4d levels with those in 8 patients with cervical spongylosis.
• Statistical analysis to identify significant differences and correlations.

Main Results:

• Elevated CSF C4d levels (more than 2 SD from the mean) were found in patients with proximal demyelination.
• CSF C4d levels suggest both intrathecal synthesis and contribution from systemic circulation.
• A potential correlation between CSF C4d and radicular involvement in demyelinating polyneuropathy was observed.

Conclusions:

• CSF C4d levels may serve as a sensitive indicator for radicular involvement in demyelinating polyneuropathy.
• The findings suggest a role for complement activation in the pathogenesis of these conditions.
• Further research is warranted to validate CSF C4d as a diagnostic biomarker.