In the few studies conducted specifically on patients who had IgA vasculitis with nephritis, deposits of C5b-9 were present in the mesangium and capillary wall, colocalized with IgA and C3–containing immune complexes (52, 61, 75, 85, 99, 139), along the tubular basement membrane, and in the vascular wall (75, 96). The gene discussed is C3; the disease is Henoch-Schoenlein purpura.