Interleukin-17 family in health and immune diseases: From origin to clinical implications

The interleukin-17 family is the key group of cytokines and displays a broad spectrum of biological functions, including regulating the inflammatory cascade in various autoimmune and inflammatory diseases, such as multiple sclerosis, neuromyelitis optica spectrum disorder, myasthenia gravis, Guillain-Barre syndrome, acute disseminated encephalomyelitis, diabetes, inflammatory skin diseases, joint inflammation, and cancer. Although the function of the interleukin-17 family has attracted increasing research attention over many years, the expression, function, and regulation mechanisms of different interleukin-17 members are complicated and still only partially understood. Currently, the interleukin-17A pathway is considered a critical therapeutic target for numerous immune and chronic inflammatory diseases, with several monoclonal antibodies against interleukin-17A having been successfully used in clinical practice. Whether other interleukin-17 members have the potential to be targeted in other diseases is still debated. This review first summarizes the recent advancements in understanding the physicochemical properties, physiological functions, cellular origins, and downstream signaling pathways of different members and corresponding receptors of the interleukin-17 family. Subsequently, the function of interleukin-17 in various immune diseases is discussed, and the important role of interleukin-17 in the pathological process of immune diseases is demonstrated from multiple perspectives. Then, the current status of targeted interleukin-17 therapy is summarized, and the effectiveness and safety of targeted interleukin-17 therapy are analyzed. Finally, the clinical application prospects of targeting the interleukin-17 pathway are discussed.