Interleukin-22 is increased in multiple sclerosis patients and targets astrocytes

Background: increasing evidences link t helper 17 (th17) cells with multiple sclerosis (ms). in this context,interleukin-22 (il-22),a th17-linked cytokine,has been implicated in blood brain barrier breakdown and lymphocyte infiltration. furthermore,polymorphism between ms patients and controls has been recently described in the gene coding for il-22 binding protein (il-22bp). here,we aimed to better characterize il-22 in the context of ms. methods: il-22 and il-22bp expressions were assessed by elisa and qpcr in the following compartments of ms patients and control subjects: (1) the serum,(2) the cerebrospinal fluid,and (3) immune cells of peripheral blood. identification of the il-22 receptor subunit,il-22r1,was performed by immunohistochemistry and immunofluorescence in human brain tissues and human primary astrocytes. the role of il-22 on human primary astrocytes was evaluated using 7-aad and annexin v,markers of cell viability and apoptosis,respectively. results: in a cohort of 141 ms patients and healthy control (hc) subjects,we found that serum levels of il-22 were significantly higher in relapsing ms patients than in hc but also remitting and progressive ms patients. monocytes and monocyte-derived dendritic cells contained an enhanced expression of mrna coding for il-22bp as compared to hc. conclusions: we show that (1) there is a dysregulation in the expression of il-22 and its antagonist,il-22bp,in ms patients,(2) il-22 targets specifically astrocytes in the human brain,and (3) this cytokine confers an increased survival of the latter cells. © 2015 perriard et al.