Intravenous immunoglobulin acts on the complement system;75the neonatal fragment crystallizable (Fc) receptor (FcRn) recirculating immunoglobulin G (IgG) and increasing its half-life possibly competes for the binding site in nerves with autoantibodies that are probably present in patients with CIDP.76 This evidence concerns the gene FCGRT and chronic inflammatory demyelinating polyradiculoneuropathy.