Sensitivity and Specificity of Autoantibodies Against CD74 in Nonradiographic Axial Spondyloarthritis.

Objective: Autoantibodies against CD74 (anti-CD74) are associated with ankylosing spondylitis (AS). The present multicenter study, the International Spondyloarthritis Autoantibody (InterSpA) trial, was undertaken to compare the sensitivity and specificity of anti-CD74 and HLA-B27 in identifying patients with nonradiographic axial spondyloarthritis (axSpA).

Methods: Patients ages 18-45 years with inflammatory back pain of ≤2 years' duration and a clinical suspicion of axSpA were recruited.