Increased serum interleukin-17 and peripheral Th17 cells in children with acute Henoch-Schönlein purpura

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-Schönlein purpura (HSP).

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.

Children with acute HSP had significantly higher serum levels of IL-17, IL-6 and transforming growth factor-β 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.

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.