PATHOLOGY OF IgA NEPHROPATHY

Idiopathic IgA Nephropathy (IgAN) has been recognized as the most common form of glomerulonephritis worldwide since its original description by Berger and Hinglais. Initially considered as a benign disease, the natural history has changed considerably with studies showing an incidence of chronic renal failure ranging from 20 to 40%. The highly variable clinical course has resulted in efforts to determine clinical, laboratory, and histologic features that predict the development of renal failure in IgAN. Light microscopic appearances and clinical features can vary considerably, reflecting the many patterns of histopathologic injury seen. Closely associated with IgAN is Henoch – Schonlein purpura (HSP), a small vessel systemic vasculitis characterized by small blood vessel deposition of IgA predominantly affecting the skin, joints, gut, and kidney. The nephritis of HSP is also characterized by mesangial IgA deposition and may be histologically indistinguishable from IgAN. This article focuses on IgAN considering especially information regarding its prevalance, histopathologigal, immunofluorescence findings and in particular, focussing on growing understanding of the pathogenesis of IgAN.