对银屑病（psoriasis vulgaris，PV）和代谢综合征（metabolic syndrome，MetS）之间的潜在病理生理学联系尚不完全清楚。本研究旨在调查PV患者伴有MetS的血清白细胞介素(IL)-9水平和组织中IL-9及其受体的水平，并分析IL-9水平与银屑病严重程度和MetS之间的相关性。本研究纳入了75例伴有MetS的PV患者、57例无MetS的PV患者、20名健康献血者和7名健康皮肤供体。从所有个体中获取了临床、社会人口学和人体测量学数据。测量了空腹血糖、胰岛素、血脂谱水平以及血清中IL-9和IL-17A的水平。使用免疫组化方法确定了PV患者和健康对照组中皮肤标本中IL-9及其受体的表达。用五种促炎症细胞因子(tumor necrosis factor-α, oncostatin M, IL-22, IL-17A和IL-1α) 刺激正常人表皮角质细胞建立银屑病角质细胞模型，然后用IL-9处理。使用定量实时聚合酶链扩增方法测量了他们抗菌肽和趋化因子的mRNA水平。伴MetS的PV患者血清中IL-9水平和组织中IL-9及其受体的水平升高。IL-9水平与IL-17A水平呈正相关；然而，IL-9水平与银屑病面积严重指数之间没有显著相关性。IL-9水平与MetS的存在及其组分呈正相关。与此相应地，IL-9水平与腰围、体重指数、家庭模型评估胰岛素抵抗、血压和甘油三酯水平呈正相关，与高密度脂蛋白胆固醇水平呈负相关。此外，IL-9在银屑病角质细胞模型中刺激了抗菌肽和趋化因子的表达。我们的研究结果证实，较高的IL-9水平与PV并发MetS相关，表明IL-9可能是PV和MetS之间的联系。© 2023 Yan et al.

The underlying pathophysiology linking psoriasis vulgaris (PV) and metabolic syndrome (MetS) is not fully understood. The present study aimed to investigate the serum level of interleukin (IL)-9 and tissue levels of IL-9 and its receptor in PV patients with MetS and analyze the correlation of IL-9 levels with psoriasis disease severity and MetS.This study enrolled 75 PV patients with MetS, 57 PV patients without MetS, 20 healthy blood donors, and 7 healthy skin donors. Clinical, socio-demographic, and anthropometric data were obtained from all individuals. Fasting blood glucose, insulin, lipid profile levels, and serum levels of IL-9 and IL-17A were measured. The expression of IL-9 and its receptor in skin specimens in PV patients and healthy controls was determined using immunohistochemistry. Normal human epidermal keratinocytes were stimulated with five pro-inflammatory cytokines (tumor necrosis factor-α, oncostatin M, IL-22, IL-17A, and IL-1α) to establish a psoriatic keratinocyte model and subsequently treated with IL-9. Their mRNA levels of antimicrobial peptides and chemokines were measured using quantitative real-time polymerase chain reaction.Serum level of IL-9 and tissue levels of IL-9 and its receptor were upregulated in PV patients with MetS. IL-9 level was positively correlated to IL-17A level; however, no significant correlation of IL-9 level with psoriasis area severity index was observed. IL-9 level had a positive correlation with the presence of MetS and its components. Correspondingly, IL-9 level positively correlated with waist circumference, body mass index, homeostasis model assessment-insulin resistance, blood pressure, and triglyceride level and negatively correlated with high-density lipoprotein cholesterol level. Additionally, IL-9 stimulated the expression of antimicrobial peptides and chemokines in a psoriatic keratinocyte model.Our findings confirmed that higher IL-9 level is associated with PV complicated by MetS, suggesting that IL-9 may be a link between PV and MetS.© 2023 Yan et al.