Biomarkers in spondyloarthritis.

Key challenges in the management of spondyloarthritis focus on the lack of availability of measures of disease activity and the inability to predict joint damage or response to treatment, which is expensive and associated with potentially serious toxicity. Recent studies have focused on the possible contribution of soluble biomarkers, which have been selected based on current understanding of their role in inflammation and/or their association with turnover of joint matrix. Emerging candidates for disease activity markers include interleukin-6 and soluble cytotoxic T lymphocyte associated molecule-4. Potential predictors of damage include metalloproteinase-3 and sclerostin. Acute-phase reactants C-reactive protein and serum amyloid A and interleukin-6 are currently the best predictors of treatment response. Significant study limitations are small sample size and the lack of multivariate analyses that can determine whether the biomarker contributes information that is independent of other clinical and laboratory variables used in routine care.