The Role of Chitinase-3-Like Protein 1(YKL-40) as a Biomarker of Psoriatic Arthritis

Abstract

Background Psoriatic arthritis (PsA) is a chronic multifaceted inflammatory seronegative arthritis. Plasma YKL-40 is an inflammatory biomarker. Objective To evaluate the role of Chitinase-3-like protein 1 (YKL-40) as a diagnostic biomarker in psoriatic arthritis (PsA) patients and determine its value in assessment of disease activity and severity in PsA patients. Patients and Methods This study included twenty five adult patients with clinical evidence of PsA and twenty five healthy matched age and sex as control group. All underwent history, laboratory investigation, clinical examination, assessment of disease activity using Disease Activity in PSoriatic Arthritis (DAPSA) Score and assessment of severity of PsA using Psoriasis Area and Severity Index (PASI), Nail Psoriasis Severity Index (NAPSI), Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), Leeds Enthesitis Index (LEI) and examination of dactylitis. Results The mean age of patients was 39.72 ± 11.94. Also, The mean age of healthy controls was 42.88 ± 12.11. There was highly statistically significant difference regarding the serum levels of YKL- 40 (P < 0.01) between the patients and the control groups (P < 0.01). The receiver operating characteristic curve (ROC) curve of YKL -40 showed that the sensitivity and the specificity of YKL- 40 in diagnosis of PsA were 96% and 92% respectively. There were statistically significant positive correlations between YKL- 40 levels (μl/mL) and each of PASI score (p = 0.005) (r = 0.539) and DAPSA score (p = 0.007) (r = 0.526). Conclusion YKL- 40 measurement may serve as a diagnostic biomarker for PsA, as it has the potential to contribute to the fundamental processes underlying the pathogenesis of PsA. So, the results of this study suggested that the addition of YKL- 40 as a serological marker has a valuable role in diagnosis of PsA and reflection of disease activity.