Effects of retinoic acid on immunity and inflammation in patients with <i>Psoriasis vulgaris</i>

Abstract

Purpose: To investigate the effect of retinoic acid on immune and inflammatory factors in patients with psoriasis vulgaris, and its underlying mechanism of action.Methods: A total of 20 P. vulgaris (PV) patients from Dongtai People's Hospital were divided into two groups, with 10 patients receiving retinoic acid and 10 receiving calcipotriol. The patients' clinical parameters, psoriasis area and severity index were evaluated after one month of treatment. Enzymelinked immunosorbent assay (ELISA) was used to measure the concentrations of interleukin-10 and interleukin-17 in the patients' peripheral blood, while the proportion of T helper immune cells that expressed IL-17a and regulatory T immune cells were determined via flow sorting. Expressions of Notch1 in psoriatic lesions and CD4+T cells were determined by quantitative real time-polymerase chain reaction (qRT-PCR).Results: Retinoic acid significantly reduced psoriasis area and severity index. Furthermore, retinoic acid decreased the concentration of IL-17, increased the concentration of IL-10, lowered the percentage of Th17 cells, but elevated the percentage of Treg immune cells (p < 0.05). Expression of Notch1 in skin lesions and CD4+T cells was lower in the retinoic acid group than in the calcipotriol group (p < 0.05).Conclusion: Expression of Notch1 is decreased in skin tissue lesions of PV patients receiving oral retinoic acid treatment. Thus, retinoic acid influences Th17/Treg immune balance by regulating Notch1 signaling pathway in PV patients, and therefore can potentially be developed for the treatment of psoriasis.