Fas-mediated T-cell apoptosis in chronic inflammatory demyelinating polyneuropathy.

The Fas receptor is expressed by activated lymphocytes and is involved in switching off the immune response. Defective Fas function causes the autoimmune lymphoproliferative syndrome, but is also involved in common autoimmune disorders. Fas-mediated T-cell apoptosis is impaired in chronic inflammatory demyelinating polyneuropathy (CIDP), but not in Guillain-Barré syndrome (GBS). The defect seems to have a genetic component and involve the extrinsic apoptotic pathway mediated by caspase-8. The analysis of clinical features shows that Fas function is lower in CIDP patients with a progressive course and axonal damage, suggesting that defective Fas function favors not only CIDP development but also its aggressive evolution. Moreover, testing T-cell Fas function in patients with acute-onset demyelinating polyneuropathy can help in early discrimination between GBS and acute-onset CIDP.