Severe Guillain-Barré syndrome: an association with IgA anti-cardiolipin antibody in a series of 92 patients.

To determine whether anti-cardiolipin antibodies (ACA) are associated with acute Guillain-Barré syndrome (GBS), we studied sera from 92 patients with GBS, 82 age- and sex-matched hospital controls and 24 patients with uncomplicated cytomegalovirus or Campylobacter jejuni infection, using an isotype-specific ACA enzyme-linked immunosorbent assay (ELISA). IgA ACA titres (but not IgG ACA or IgM ACA) were significantly elevated (P = 0.002) in GBS patients compared to controls, and associated with peak disease severity (P = 0.01), but not initial or residual disability, nor duration of neuropathy. Abnormal IgG ACA may cause or result from myelin damage in GBS.