IgA nephropathy: Update on pathogenesis and treatment.

The pathogenesis of immunoglobulin (Ig) A nephropathy is described through a "4-hit" model involving production of galactose-deficient IgA, production of autoantibodies to galactose-deficient IgA, and subsequent deposition of immune complexes in the kidney glomerulus. Diagnosis remains dependent on a kidney biopsy, often after hematuria or proteinuria is detected on urinalysis. The cornerstone of therapy still involves renin-angiotensin-aldosterone system inhibitors or corticosteroids; however, new therapies targeting key aspects of the pathogenesis of IgA nephropathy are being introduced.