25-羟基胆固醇（25HC）由巨噬细胞中的胆固醇25-羟化酶（CH25H）产生，并已报道能够抑制严重急性呼吸综合征冠状病毒2等病毒病原体的复制。同时，巨噬细胞中的CH25H表达会被干扰素（IFNs）大量诱导。为了更好地理解COVID-19患者血清中25HC水平的增加以及其与临床症状的关系，我们检测了17名住院COVID-19患者的血清中的25HC和其他五种氧化固醇水平。入院时，25HC和27-羟基胆固醇（27HC）血清水平升高，而7-酮胆固醇（7KC）水平在COVID-19患者中低于健康对照组。25HC血清水平和干扰素-γ和白细胞介素6等疾病严重度标志物之间没有显著相关性。糖皮质激素有效地抑制小鼠白血病巨噬细胞系RAW 264.7中胆固醇25-羟化酶（CH25H）mRNA的表达，无论是否有脂多糖或干扰素；因此，它可能能够减轻COVID-19对25HC血清水平的影响。我们的结果强调了25HC可以作为严重COVID-19的独特生物标志物和潜在的治疗候选物，用于检测COVID-19和其他传染性疾病的严重程度。Copyright © 2022. Published by Elsevier Inc.

25-hydroxycholesterol (25HC), produced by cholesterol 25-hydroxylase (CH25H) in macrophages, has been reported to inhibit the replication of viral pathogens such as severe acute respiratory syndrome coronavirus-2. Also, CH25H expression in macrophages is robustly induced by interferons (IFNs).To better understand the serum level increase of 25HC in coronavirus disease 2019 (COVID-19) and how it relates to the clinical picture.We measured the serum levels of 25HC and five other oxysterols in 17 hospitalized COVID-19 patients.On admission, 25HC and 27-hydroxycholesterol (27HC) serum levels were elevated; however, 7-ketocholesterol (7KC) levels were lower in patients with COVID-19 than in the healthy controls. There was no significant correlation between 25HC serum levels and disease severity markers, such as interferon-gamma (IFN-γ) and interleukin 6. Dexamethasone effectively suppressed cholesterol 25-hydroxylase (CH25H) mRNA expression in RAW 264.7 cells, a murine leukemia macrophage cell line, with or without lipopolysaccharide or IFNs; therefore, it might mitigate the increasing effects of COVID-19 on the serum levels of 25HC.Our results highlighted that 25HC could be used as a unique biomarker in severe COVID-19 and a potential therapeutic candidate for detecting the severity of COVID-19 and other infectious diseases.Copyright © 2022. Published by Elsevier Inc.