Autoimmune kidney diseases.

The second most common cause of chronic renal failure is glomerulonephritis, which is a collective term used for numerous diseases with the common denominator of histological renal inflammation emanating from the glomerular tuft. Whether all forms of glomerulonephritis should be considered as autoimmune disease is debatable, but immune mechanisms are important in all of them. This review focuses on four relatively well delineated forms of primary glomerulonephritis: Goodpastures or anti-GBM disease, IgA nephritis, membranous nephropathy and membranoproliferative glomerulonephritis. The autoantibodies are directed either to molecules within the glomeruli, such as the glomerular basement membrane in anti-GBM disease and to the podocytes in membranous glomerulonephritis, or to components of the immune system such as C3 convertase in membranoproliferative glomerulonephritis and IgA in IgA nephritis. Differences in diagnostic practices and classification controversies obscure comparative epidemiological studies, but there seem to be huge differences between incidence rates between countries and over time, both genetic factors and infections seem to matter but strong indications for a role of other environmental factors are still lacking.