Serum Calprotectin as an Inflammatory Marker in a Cohort of Egyptian Patients with Psoriatic Arthritis and its Correlation with Disease Activity and Radiological Findings

Abstract Background Psoriatic arthritis (PsA) is a chronic inflammatory arthritis associated with psoriasis and is found in about 20 to 30% of psoriatic patients. The use of inflammatory markers can be disappointing in PsA, since they are elevated in only half of the patients with PsA., in this study we assessed serum calprotectin as a marker of inflammation in psoriatic arthritis and correlated it to disease activity and radiological findings. Objective To measure serum calprotectin level in psoriatic arthritis patients and to assess its association with disease activity score and radiological findings using musculoskeletal ultrasound. Methods This was a Case-Control Study Rheumatology inpatient departments and outpatient clinics at Ain Shams University Hospitals. This study was conducted on 50 patients with psoriatic arthritis according to the classification criteria for psoriatic arthritis (CASPAR) criteria and 30 Normal subjects with no past medical history and with no family history of psoriasis. Results Patients serum calprotectin level had statistically significant higher value in comparison to the control group P-Value < 0.001., and with cutoff point 106.36 ng/ml with sensitivity 98% and specificity of 86.6 %, There was highly statistically significant relation between the level of serum calprotectin and synovial hypertrophy in small hand joints P-Value=0.004 and it can predict synovial hypertrophy in hands by joint ultrasound at the level of 258.9 ng/ml with sensitivity and specificity of 71%, 83% respectively There was also a with statistically significant relation nail bed affection in ultrasound P-Value=0.034. Multiple regression analysis was done in psoriatic arthritis patients and it was found that serum calprotectin was the most predictive for the presence of psoriatic arthritis in comparison to ESR and CRP. Conclusion in psoriatic arthritis patients, serum calprotectin level is significantly higher and is correlated to radiographic and nail changes. Further studies are required to define a specific cutoff serum level for diagnosis.