['Psoriasis is a systemic inflammatory skin disease. MicroRNAs (miRNAs) are a class of small non-coding RNA molecules that recently have been found in the blood to be relevant as disease biomarkers.', 'We aimed to explore miRNAs potential as blood biomarkers for psoriasis.', 'Using microarray and quantitative real-time PCR we measured the global miRNA expression in whole blood, plasma and peripheral blood mononuclear cells (PBMCs) from patients with psoriasis and healthy controls.', 'We identified several deregulated miRNAs in the blood from patients with psoriasis including miR-223 and miR-143 which were found to be significantly upregulated in the PBMCs from patients with psoriasis compared with healthy controls (FCH=1.63, P<0.01; FCH=2.18, P<0.01, respectively). In addition, miR-223 and miR-143 significantly correlated with the PASIscore (r=0.46, P<0.05; r=0.55, P<0.02, respectively). Receiver-operating characteristic analysis (ROC) showed that miR-223 and -143 have the potential to distinguish between psoriasis and healthy controls (miR-223: area under the curve (AUC)=0.80, miR-143: AUC=0.75). Interestingly, after 3-5 weeks of treatment with methotrexate following a significant decrease in psoriasis severity, miR-223 and miR-143 were significantly downregulated in the PBMCs from patients with psoriasis.'] Are microRNA-223 and miR-143 important systemic biomarkers for disease activity in psoriasis?