Circulating Levels of Osteopontin in Patients With Psoriasis: A Systematic Review and Meta-Analysis

Abstract

Background: Both Th1 and Th17 have been proposed to be pathogenically essential in psoriasis. Osteopontin (OPN) is known to enhance Th1 responses, inhibit Th2 ones, and take part in the modulation of Th17 cell lineage. Due to its impact on Th1/Th17 immune responses, several reports have suggested that OPN may be of pathogenic importance in psoriasis. Our objective was to review the literature for studies that have assessed the circulating levels of OPN in psoriatic cases and controls and to meta-analyze the evidence obtainable. Methods: Search was performed in PubMed, Central, and Embase. Eligible were studies that have assessed OPN concentrations in patients with psoriasis and a group of reference. Results: Patients with psoriasis had increased OPN concentrations compared with controls (random-effects model, standardized mean difference: 1.58 ng/mL, 95% confidence interval: 0.90-2.26; P < .0001]). Heterogeneity among studies was high ( I2: 92.2%; P < .0001). The meta-regression analysis showed that the study quality (RTI score) reduced heterogeneity ( I2: 85.2%; P < .005), but not age, body mass index (BMI), Psoriasis Area Severity Index, or matching for BMI. Conclusions: This meta-analysis provided evidence that OPN is involved in the pathogenesis of psoriasis, enlarging the list of cytokines able to stimulate the inflammatory response in this disease.