Henoch-Schonlein purpura (HSP) is an IgA-mediated disorder that most commonly occurs in children. Its etiology and pathogenesis remain unknown. In recent years, numerous studies have pointed to a dysfunction of T cells in the pathogenesis of HSP. Here, we will review the epidemiology, clinical and molecular characteristics of HSP, as well as abnormalities of Th cell subsets in this disorder. Fi...