Background: Interleukin (IL)-17 and Th17 cells have been involved in many autoimmune diseases. The aim of this study is to investigate the involvement of IL-17 and Th17 cells in the pathogenesis of childhood Henoch-Schonlein purpura (HSP ). Methods: Serum and supernatant levels of cytokines and chemokines were analyzed by enzyme-linked immunosorbent assay (ELISA). Using intracellular staining, the frequency of peripheral Th17 and Th1 cells was studied by flow cytometry. Results: Children with acute HSP had significantly higher serum levels of IL-17, IL-6 and transforming growth factor-beta than healthy controls. The IL-17 levels in culture supernatants of peripheral blood mononuclear cells with anti-CD3 and CD28 antibody stimulation were much higher in patients with HSP (281.2 +/- 91.4 vs. 47.7 +/- 22.6 pg/ml, p = 0.022). The patients also had more Th17 cells (1.67 +/- 0.36% vs. 0.71 +/- 0.15%, p = 0.033) but not Th1 cells in peripheral blood. Moreover, IL- 17 could promote human endothelial cells to produce chemoattractants IL-8 and monocyte chemotactic protein-1. Conclusion: The increased frequency of peripheral Th17 cells and serum IL-17 levels are shown in childhood HSP that may in part contribute to vascular inflammation, suggesting cellular immunity is likely to be involved in the process of HSP. ; 醫學檢驗暨生物技術學系 ; 醫學院 ; 期刊論文