T-CELL-DEPENDENT ACTIVITY OF GANGLIOSIDE GM1-SPECIFIC B-CELLS IN GUILLAIN-BARRE-SYNDROME AND MULTIFOCAL MOTOR NEUROPATHY IN-VITRO

Synthesis of anti-ganglioside GM1 antibodies of the IgM class by perip heral blood mononuclear cells (PBMNC) from patients with immune-mediat ed neuropathies and motor neuron diseases and from normal controls was stimulated by Pokeweed mitogen (PWM) in vitro. In patients with acute Guillain-Barre syndrome or multifocal motor neuropathy and high serum titers of IgM anti-ganglioside GM1 antibodies this culture response w as greatly enhanced as compared to controls and already detectable in unstimulated cultures. Limiting dilution analysis demonstrated high fr equencies of GM1-specific B cells in these patients. Anti-ganglioside GM1 antibodies of the IgG and IgA class were only produced by PBMNC fr om patients with Guillain-Barre syndrome corresponding to serum titers . In cultures taken at intervals over 6 months in vitro B cell activit y for IgM, IgG and IgA anti-ganglioside GM1 antibodies in two Guillain -Barre syndrome patients declined accompanied by clinical improvement and falling serum titers. We conclude that GM1-specific PWM-responsive B cells pre-exist in peripheral blood and respond to T cell-dependent stimulation in Guillain-Barre syndrome and multifocal motor neuropath y.