Biomarkers for the Diagnosis of Axial Spondyloarthritis

Axial spondyloarthritis (axSpA) is a chronic inflammatory rheumatic disease affecting mainly the spine and sacroiliac joints, but also peripheral joints and extra-articular tissues such as the eyes, skin and intestines. Early diagnosis remains challenging, particularly in patients with non-radiographic disease, where clear imaging abnormalities may be absent.

Current diagnostic approaches rely on a combination of clinical symptoms, imaging techniques such as MRI, and laboratory markers including HLA-B27 and C-reactive protein (CRP). However, these approaches often lack sufficient sensitivity and specificity in early disease stages, making it difficult to distinguish axSpA from nonspecific chronic low back pain. As a result, diagnosis is frequently delayed by several years, postponing early treatment initiation and optimal disease management. There is therefore a strong unmet need for objective biomarkers that improve early axSpA diagnosis and clinical decision-making.