Galectin-9 (Gal-9) is a β-galactoside binding lectin known for its immunomodulatory role in various microbial infections. Gal-9 is expressed in all organ systems and localized in the nucleus, cell surface, cytoplasm and the extracellular matrix. It mediates host-pathogen interactions and regulates cell signalling via binding to its receptors. Gal-9 is involved in many physiological functions such as cell growth, differentiation, adhesion, communication and death. However, recent studies have emphasized on the elevated levels of Gal-9 in autoimmune disorders, viral infections, parasitic invasion, cancer, acute liver failure, atopic dermatitis, chronic kidney disease, type-2 diabetes, coronary artery disease, atherosclerosis and benign infertility-related gynecological disorders. In this paper we have reviewed the potential of Gal-9 as a reliable, sensitive and non-invasive biomarker of disease severity. Tracking changes in Gal-9 levels and its implementation as a biomarker in clinical practice will be an important tool to monitor disease activity and facilitate personalized treatment decisions.

Galectin-9（Gal-9）是一种β-半乳糖苷结合凝集素，以其在各种微生物感染中的免疫调节作用而闻名。Gal-9在所有器官系统中表达，并位于细胞核，细胞表面，细胞质和细胞外基质中。它介导宿主与病原体的相互作用，并通过与其受体结合来调节细胞信号传导。Gal-9参与许多生理功能，例如细胞生长，分化，粘附，交流和死亡。然而，最近的研究强调自身免疫性疾病，病毒感染，寄生虫侵袭，癌症，急性肝衰竭，特应性皮炎，慢性肾脏疾病，2型糖尿病，冠状动脉疾病，动脉粥样硬化和良性不育的Gal-9水平升高相关的妇科疾病。在本文中，我们回顾了Gal-9作为可靠的，疾病严重程度的敏感和非侵入性生物标志物。跟踪Gal-9水平的变化及其在临床实践中作为生物标记物的实施将是监测疾病活动并促进个性化治疗决策的重要工具。