The Expression of Vitamin D Receptor on Peripheral Blood Mononuclear Cells in Patients with Psoriasis

Vitamin D plays an important role in psoriasis, but its involvement in pathogenesis remains unclear. This study aimed to evaluate vitamin D receptor (VDR) expression on peripheral blood mononuclear cells (PBMCs) in patients with psoriasis and healthy controls and to study the effects of the Etanercept treatment on VDR expression on PBMCs in patients with psoriasis. Twenty patients with moderate to severe psoriasis received treatment with Etanercept for 24 weeks. The age- and sex-matched controls did not receive any intervention. VDR expression on CD3⁺ lymphocytes and CD14⁺ monocytes, and serum levels of total and free 25-hydroxyvitamin D (25(OH)D) and 1,25-dihydroxy vitamin D (1,25(OH)₂D) were analyzed at baseline, after 10-12 weeks, and after 24 weeks in both groups. VDR expression was analyzed using flow cytometry. We observed higher expression of the VDR on CD14⁺ monocytes in psoriasis patients compared to healthy controls at baseline. This difference was no longer significant after 24 weeks of the Etanercept treatment. The patients with psoriasis improved clinically. However, VDR expression was unaltered during the Etanercept treatment, and there was no correlation between VDR expression and disease severity.