Elevated Serum Amyloid A2 and A4 in Patients With Guillain-Barré Syndrome.

Background and purpose: Guillain-Barré syndrome (GBS) is an autoimmune-mediated disorder characterized by demyelinating or axonal injury of the peripheral nerve. Our aim is to determine whether serum amyloid A (SAA) is a biomarker of demyelinating injury and disease severity in patients with GBS.

Methods: This study retrospectively enrolled 40 patients with either the demyelinating or axonal GBS and sex- and age-matched controls with other neurological diseases as well as healthy subjects. The demographic and clinical features at entry were collected. The serum levels of the SAA isoforms SAA1, SAA2, and SAA4 were determined in the patients with GBS and the controls using the enzyme-linked immunosorbent assay and analyzed for the associations between levels of different SAA isoforms and the clinical features of the patients.

Results: The levels of SAA2 and SAA4 were significantly higher in patients with GBS than in both the other neurological disease controls and the healthy subjects (p<0.05 for all). The level of SAA1 did not differ between patients with GBS and the controls. The level of SAA2 was considerably higher in GBS patients with antecedent infection than in those without infection (p=0.020). The levels of different SAA isoforms were not associated with the disease severity or other clinical features of patients with GBS (p>0.05 for all).

Conclusions: Increased levels of SAA2 and SAA4 may only represent the acute inflammatory status and so cannot be utilized as biomarkers of the disease severity or demyelinating injury in patients with GBS.