 Any immune complex disease—including systemic lupus erythematosus, acute proliferative glomerulonephritis, Henoch–Schönlein purpura, and IgA nephropathy—that involves the glomerulus may progress to RPGN if severe enough.Also known as pauci-immune RPGN, type III RPGN accounts for 55% of RPGN and features neither immune complex deposition nor anti-GBM antibodies.Instead, the glomeruli are damaged in an undefined manner, perhaps through the activation of neutrophils in response to ANCA.