Background: Guillain-Barre syndrome (GBS) is an acquired demyelinating peripheral neuropathy. It has shown that macrophage activation contribute to the pathogenesis of GBS. Therefore macrophage-mediated factors could be the potential markers for disease diagnosis and status of GBS. Methods: We measured serum concentrations of 4 macrophage-mediated factors, including interleukin-6 (IL-6), transforming growth factor-beta 1 (TGF-beta 1), vascular cell adhesion protein 1 (VCAM-1) and vascular endothelial growth factor (VEGF), in 23 chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), 28 GBS, 11 Miller-Fisher syndrome (MFS), 40 multiple sclerosis (MS), and 12 Alzheimer's disease (AD) patients, as well as 15 healthy controls. Results: Serum TGF-beta 1 concentration of GBS patients (35.94 +/- 2.55 ng/ml) was significantly higher compared with CIDP (25.46 +/- 1.40 ng/ml, P < 0.001), MFS (25.32 +/- 2.31 ng/ml, P = 0.010), MS (21.35 +/- 0.90 ng/ml, P < 0.001) and AD patients (22.92 +/- 1.82 ng/ml, P < 0.001), as well as healthy controls (23.12 +/- 1.67 ng/ml, P < 0.001). A positive correlation between serum TGF-beta 1 concentrations and Hughes' functional grading scales was observed in GBS patients. Serum concentrations of IL-6, VCAM-1 and VEGF were similar between the studied groups. Conclusion: The high serum concentrations of TGF-beta 1 and the correlation between serum TGF-beta 1 concentration and disease severity highlight the potential of TGF-beta 1 as a biomarker of GBS. (C) 2016 Elsevier B.V. All rights reserved.