IgA nephropathy: to treat or not to treat?

IgA nephropathy (Berger's disease) is thought to be the most common primary glomerulonephritis in the world. Characteristically, it presents with intermittent macroscopic hematuria in association with upper respiratory infections. The diagnosis is established by demonstrating predominant IgA deposits in the glomerular mesangium. One third of the cases progress slowly over 25 years to glomerulosclerosis and end-stage renal disease. This rate of disease progression has not been altered by any known treatment, including the use of corticosteroids or cyclosporine. The pathogenesis of this disease is unknown; however, recent data implicated oxygen free radicals in the development of IgA nephropathy. The recent controlled, double-blind, 2-year study from the Mayo Clinic showed that fish oil slowed the progression of IgA nephropathy. This contrasts with the previous studies where the use of fish oil either accelerated the rate of deterioration of renal function in patients with IgA nephropathy or showed no change compared to untreated subjects. Furthermore, in experimental uremia, marked renal functional deterioration with fish oil administration has been reported. Experimental models of IgA nephropathy have been developed in the past few years. In addition, molecular biology offers an unique opportunity to study kidney tissue obtained from patients and animals with IgA nephropathy. These advances will enable the identification of the critical sequence of events that result in renal injury and provide new insight into the pathogenesis and progression of IgA nephropathy. This will help clarify the role of free oxygen radical release on disease progression, and an understanding on the mechanisms of antioxidants, such as vitamin E, in preventing such renal injury.