Serum Monocyte Chemotactic Protein-1 Concentrations Distinguish Patients With Ankylosing Spondylitis From Patients With Mechanical Low Back Pain

Objectives: This study aimed to identify potential blood-derived biomarkers distinguishing patients with ankylosing spondylitis from those with mechanical low back pain. Methods: Serum and synovial fluid samples from our cohorts were assayed by using enzyme-linked immunosorbent assay for the following inflammatory biomarkers: interleukin (IL)-1 alpha, IL-6, IL-8, IL-17, IL-23, monocyte chemotactic protein (MCP)-1, macrophage inflammatory proteins (MIP)-1 alpha, MIP-1 beta, tumor necrosis factor-alpha (TNF-alpha), interferon-alpha (IFN-alpha), IFN-beta, metalloproteinase (MMP-3), and bone morphogenetic protein 7 (BMP-7). Results: After screening, a panel of serum and synovial fluid samples with a series of potential biomarkers, cytokines including IL-6, IL-8, MMP-3, and MCP-1 were selected for additional testing because they exhibited higher concentrations than paired serum samples in the synovial fluid. Sera obtained from 50 patients with ankylosing spondylitis and 27 patients with mechanical low back pain were measured for these biomarkers. Conclusions: The MCP-1 serum was identified as a biomarker candidate, distinguishing ankylosing spondylitis from mechanical low back pain with a sensitivity of 96% and a specificity of 83.3%.