Chronic inflammatory demyelinating polyneuropathy (CIDP) is the most common
chronic autoimmune neuropathy. While both cell-mediated and humoral mechanisms
contribute to its pathogenesis, the rapid clinical response to plasmapheresis
implicates a circulating factor responsible for peripheral nerve injury. We
report that treatment-naïve patients with CIDP show increased serum and CSF
levels of the anaphylatoxin C5a and the soluble terminal complement complex
(sTCC). Systemic terminal complement activation correlates with clinical
disease severity as determined by the Inflammatory Neuropathy Cause and
Treatment (INCAT) disability scale. These data indicate that complement
activation contributes to peripheral nerve injury and suggest that complement
inhibition should be explored for its potential therapeutic merit in CIDP
