Anti-GM1 antibodies in patients with chronic inflammatory demyelinating polyneuropathy (CIDP) treated with intravenous immunoglobulin (IVIg).

Patients with chronic inflammatory demyelinating polyneuropathy (CIDP) and with a chronic polyneuropathy (non-CIDP) were studied for the presence of anti-GM1 antibodies. In pretreatment sera of CIDP patients, we found IgG anti-GM1 antibodies in 23%, IgM in 7%, and IgA in 14%. Predominantly motor involvement was associated with IgG and IgM anti-GM1 antibodies in CIDP patients (P = 0.002). Improvement after intravenous immunoglobulin (IVIg) therapy was not associated with anti-GM1 antibody titer before or after treatment. Anti-GM1 antibody titers before onset of treatment was not related to poor clinical outcome, although large clinical improvements after IVIg therapy were observed less often (P = 0.057) in patients with high titer anti-GM1 antibodies before treatment.