Henoch-Schonlein purpura nephritis is a small vessel vasculitis that can involve not only the kidneys but also the gut, joints and skin, to varying extents. In contrast, IgA nephropathy is recognized as a renallimited, non-systemic disease. However, Henoch-Schonlein purpura nephritis and IgA nephropathy share many immunological, histological and clinical features. Indeed, IgA nephropathy and Henoch-Schonlein purpura nephritis are thought to be related diseases.