Intrathecal antibody responses to GalC in Guillain-Barré syndrome triggered by Mycoplasma pneumoniae

Mycoplasma pneumoniae (Mp) triggers Guillain-Barré syndrome (GBS) and elicits anti-galactocerebroside (GalC) antibodies. Specifically anti-GalC IgG is associated with Mp-GBS, possibly because of its better ability to cross the blood-nerve barrier (BNB). We here investigated CSF for the presence of anti-GalC in GBS. Intrathecal anti-GalC was found in 46% of Mp-GBS patients (n=6/13), in contrast to 16% of GBS controls (n=4/25) and 0% of non-GBS controls (n=0/7). The antibodies most likely originated from increased BNB permeability and/or intrathecal synthesis. Intrathecal anti-GalC IgG was specifically associated with Mp-GBS, further supporting that anti-GalC IgG contributes to the pathogenesis of GBS. [Display omitted] •Although GBS is a peripheral neuropathy anti-GalC antibodies are found in CSF.•Intrathecal anti-GalC IgG is specifically associated with M. pneumoniae-GBS.•Anti-GalC IgG in CSF may be derived from blood and related to increased blood-nerve barrier permeability.•In one patient with additional CNS involvement, anti-GalC IgG most likely derived from intrathecal synthesis.