Sabat Robert, Wallace Elizabeth, Endesfelder Stefanie, Wolk Kerstin
Interdisciplinary Group of Molecular Immunopathology, Dermatology/Medical Immunology, University Hospital Charité, Campus Charité Mitte, Berlin, Germany.
Expert Opin Ther Targets. 2007 May;11(5):601-12. doi: 10.1517/14728222.11.5.601.
IL-19 and IL-20 are two cytokines that were discovered in 2000 and 2001, respectively. Based on the structure and location of their genes, their primary and secondary protein structures and the used receptor complexes, they were classified with IL-10, IL-22, IL-24, IL-26, IL-28 and IL-29 in the IL-10 family of cytokines, and form a subgroup with IL-24 within this family. IL-19 and IL-20 are produced by monocytes as well as non-immune tissue cells under inflammatory conditions. IL-19 and IL-20 act via a receptor complex that consists of the IL-20R1 and IL-20R2 chains. IL-20 is additionally able to signal via a second receptor complex (IL-22R1/IL-20R2). It is controversial whether or not IL-19 and IL-20 regulate the function of immune cells. However, the expression of their receptors aliments the perception that the cells of the skin, lungs and reproductive organs as well as various glands are major targets of these mediators. Results from animal experiments and massively increased expression of these mediators in human inflamed tissues support the assumption that they play an important role in the pathogenesis of a few inflammatory diseases. For this reason, the authors have reviewed the facts known at present regarding these cytokines and postulate that IL-19 and IL-20 are pharmacologically interesting distal elements of an inflammatory cascade.
白细胞介素-19（IL-19）和白细胞介素-20（IL-20）是分别于2000年和2001年发现的两种细胞因子。根据其基因的结构和位置、一级和二级蛋白质结构以及所使用的受体复合物，它们与白细胞介素-10、白细胞介素-22、白细胞介素-24、白细胞介素-26、白细胞介素-28和白细胞介素-29一起被归类于白细胞介素-10细胞因子家族，并在该家族中与白细胞介素-24形成一个亚组。在炎症条件下，单核细胞以及非免疫组织细胞均可产生IL-19和IL-20。IL-19和IL-20通过由IL-20R1和IL-20R2链组成的受体复合物发挥作用。此外，IL-20还能够通过第二种受体复合物（IL-22R1/IL-20R2）发出信号。IL-19和IL-20是否调节免疫细胞的功能仍存在争议。然而，其受体的表达使人认为皮肤、肺、生殖器官以及各种腺体的细胞是这些介质的主要靶标。动物实验结果以及这些介质在人类炎症组织中的大量表达增加支持了这样一种假设，即它们在一些炎症性疾病的发病机制中起重要作用。因此，作者回顾了目前已知的关于这些细胞因子的事实，并推测IL-19和IL-20是炎症级联反应中在药理学上具有重要意义的远端元件。
