Autoimmunity in rapidly progressive glomerulonephritis

Abstract

Rapidly progressive glomerulonephritis (RPGN) is characterized histologically by focal necrotizing glomerular lesions with crescent formation, and clinically by the development of renal failure within weeks or months. Although RPGN may be associated with a variety of systemic diseases, or develop on a background of primary glomerulonephritis, two distinct types predominate in most nephrological practices. In one, which is less common, there are autoantibodies to glomerular basement membrane (GBM) which may also react with lung basement membrane producing Goodpasture's syndrome, and in the other there are autoantibodies to neutrophil cytoplasmic antigens and clinicopathological features of small vessel vasculitis. The latter type usually occurs in the context of Wegener's granulomatosis (WG) or microscopic polyarteritis (MP), although so-called idiopathic RPGN probably forms part of the same spectrum of disease. We shall consider separately what is known of autoimmunity to glomerular antigens in these two disorders, although it has recently been recognized that both immune mechanisms may sometimes co-exist.