Demyelination induced by serum from patients with Guillain-Barré syndrome.

Sera from 16 patients with acute Guillain-Barré syndrome (GBS) and 14 healthy control subjects were injected into rat sciatic nerve and assessed for demyelinating activity by electrophysiological and histological techniques. Only fresh GBS serum, and not GBS serum stored at -20 degrees C or -70 degrees C, blocked conduction to a significantly greater extent than did fresh control serum. Conduction block developed gradually, starting within 24 hours of injection and reaching a maximum between days 3 and 6. Recovery of conduction commenced thereafter, and conduction returned to normal by day 33. Quantitative histological studies on day 6 showed that fresh GBS serum produced significantly more widespread demyelination than did stored GBS serum (p less than 0.01). Stored GBS serum showed residual demyelinating activity when compared with fresh control serum (p less than 0.01). Fresh serum obtained from 4 patients after recovery from GBS did not produce conduction block, despite it having done so during the acute phase of the disease.