Glial fibrillary acidic protein: a marker of axonal Guillain-Barrè syndrome and outcome.

Glial fibrillary acid protein (GFAP) is increased in serum and cerebrospinal fluid of patients with dementia, traumatic brain injury, stroke, and multiple sclerosis. To determine whether GFAP is increased in Guillain-Barré syndrome (GBS) we evaluated serum GFAP in 30 controls, 20 patients with acute inflammatory demyelinating neuropathy (AIDP), and 17 with primary axonal GBS. Serum GFAP levels were increased in axonal GBS (median, 0.74) compared with controls (median, 0.41; P < 0.0001) and AIDP (median, 0.58; P = 0.0015). GFAP levels correlated with Hughes grades (serum r = 0.74; P < 0.0001) 6 months after neuropathy onset. Applying the cutoff value in serum of 0.63 to the diagnosis of axonal GBS, we obtained a sensitivity of 76.5% and a specificity of 86%. Thus, serum GFAP levels may be used in GBS as a diagnostic marker of the axonal variant and to predict outcome.