Role of serum calprotectin in diagnosis of spondyloarthropathy

Background. This study aimed to investigate the role of serum calprotectin in patients with axial and peripheral spondyloarthritis (SpA), and to explore its relationship with disease activity. Patients with psoriatic arthritis (PsA) and ankylosing spondylitis (AS) were evaluated clinically, radiologically, and biochemically in comparison with healthy controls. Patients and methods. A total of 60 patients were enrolled and divided into three groups: 20 patients with axial SpA confirmed by sacroiliitis on MRI or X-ray (AS group), 20 patients with PsA and peripheral joint involvement (PsA group), and 20 age- and sex-matched healthy controls. Serum calprotectin levels were measured using ELISA and correlated with disease activity indices (ASDAS and DAPSA), inflammatory markers, and musculoskeletal ultrasound findings. Results. Serum calprotectin levels were significantly elevated in both AS and PsA groups compared to controls (p < 0.05). AS patients showed higher mean calprotectin levels than those with PsA. However, serum calprotectin demonstrated only weak or inconsistent correlations with disease activity indices. In PsA, a moderate correlation was observed with DAPSA and enthesitis scores, whereas in AS, calprotectin levels correlated weakly with ultrasound findings and enthesitis. Conclusion. Serum calprotectin may serve as a supportive biomarker for the diagnosis of both axial and peripheral SpA. However, its utility as a marker of disease activity appears limited. Further studies on larger populations are needed to establish its prognostic value and potential role in disease monitoring.