Serum calprotectin as a potential biomarker for subclinical enthesitis in psoriatic patients

Aim of the work: To assess serum calprotectin level in psoriatic patients and investigate its potential relation to clinical and ultrasonographic enthesitis. Patients and methods: The study included 45 psoriatic patients and 20 matched healthy controls. Enthesitis was assessed clinically, by musculoskeletal ultrasound (MSUS) and power Doppler, by Leeds Enthesitis Index (LEI), Maastricht Ankylosing Spondylitis Enthesitis (MASES), Spondyloarthritis Research Consortium of Canada (SPARCC) and Madrid Sonography Enthesitis Index (MASEI) scores. The Psoriasis Area, Severity Index (PASI) and Dermatology Life Quality Index (DLQI) were evaluated. Serum calprotectin was measured using enzyme-linked immunosorbent assay. Results: The study included 45 psoriatic patients with a mean age of 49.9 +/- 7.8 years and they were 23 males and 22 females with disease duration of 5.2 +/- 3 years, (0.5-11 years). Patients were categorized into those with enthesitis (n = 25; 20 clinically and 5 subclinically diagnosed by MSUS) and those without (n = 20). Serum calprotectin was significantly higher among patients with enthesitis (clinical 593.7 +/- 192. 5 ng/ml and subclinical 692 +/- 265.9 ng/ml) compared to those without (381.2 +/- 198.5 ng/ml) and to the control (111.1 +/- 15 ng/ml) (p = 0.001). The DLQI was significantly severer in patients with clinical enthesitis compared to those subclinically detected or without (p < 0.001). The acute phase reactants (erythrocyte sedimentation rate and C-reactive protein) were comparable between patients and control. Serum calprotectin significantly correlated with MASES, LEI, SPARCC and MASEI score in psoriatic patients (p < 0.001). At cutoff 141 ng/ml, calprotectin yielded specificity 69% and sensitivity 75% to detect enthesitis (p = 0.008). Conclusion: Calprotectin may be considered as a potential biomarker for detection of enthesitis in psoriatic patients. (C) 2021 Egyptian Society of Rheumatic Diseases. Publishing services provided by Elsevier B.V.