Guillain-Barré syndrome: activated complement components C3a and C5a in CSF.

Plasma and spinal fluid levels of complement activation products C3a and C5a were quantitated by radioimmunoassay in a group of 16 patients suffering from acute monophasic Guillain-Barré syndrome (GBS). Median CSF levels of C3a (118 ng/ml) and of C5a (9.6 ng/ml) were significantly elevated when compared with samples from a control group of patients with noninflammatory neurologic diseases. Plasma concentrations of these anaphylotoxic peptides were not significantly different between the two populations. Our findings indicate that the complement system is activated in the CSF of patients with acute GBS. Complement activation products may contribute to the inflammatory changes observed in this disorder.