Biomarkers in Early-stage Spondyloarthritis

Currently, no laboratory test or biomarker is cable of differentiating between patients with early-stage axSpA and persisting low back pain of other causes. Human leukocyte antigen (HLA) B27 is not an acute biomarker, but a prognostic marker for the development of axSpA.

C-reactive protein (CRP) is commonly used as an acute biomarker in different inflammatory conditions. Previous studies have shown that only 40-60% of ankylosing spondylitis (AS) patients with clinical signs of active disease have elevated levels of CRP.

Earlier studies regarding the complement C3 split product C3d have shown a correlation between inflammatory diseases like AS and elevation of C3d. Those studies were based on a small number of cases, but a newer study from 2016 has shown a correlation between different biomarkers, including C3 and new fatty lesions at MRI in Golimumab treated AS patients.

Objective To investigate the predictive value of baseline levels of C3d and hsCRP identifying bone marrow oedema (BME) at MRI of the sacroiliac joints (SIJ) at baseline.

Design: