Elevated serum interleukin-33 levels in patients with Henoch-Schönlein purpura.

Henoch-Schönlein purpura (HSP) is the most common systemic vasculitis and is known as an immunoglobulin (Ig) A related immune complex-mediated disease. However, the molecular mechanisms in the development of HSP are not yet fully understood. Herein, we investigated the serum levels of Interleukin (IL)-33 and soluble ST2 (sST2) in HSP patients and their association with disease severity and IgA autoantibodies production. The serum levels of IL-33 and sST2 were measured by double antibody sandwich enzyme-linked immunosorbent assay (ELISA) in the serum of 33 patients with HSP and 22 controls. Serum levels of IgA anti-endothelial cell antibodies (AECA) and IgA anticardiolipin antibodies (ACA) in HSP patients were detected by double antigen sandwich ELISA. Our results indicated that serum levels of IL-33 but not sST2 were significantly elevated in patients with HSP in acute stage and restored to normal levels in convalescent stage. Moreover, serum IL-33 levels were correlated with the severity of HSP and serum concentrations of AECA-IgA and ACA-IgA. Taken together, we show firstly that serum IL-33 is abnormally elevated in HSP patients. IL-33 might be associated with the IgA autoantibodies production in the pathogenesis of HSP.