Treatment of IgA nephropathy: corticosteroids, tonsillectomy, and mycophenolate mofetil

Previous studies exploring the potential of glucocorticoid therapy on proteinuria and renal survival of patients with IgA nephropathy (IgAN) indicate that corticosteroid therapy is recommended if the patients show a moderate degree of proteinuria and their creatinine clearance exceeds 70 ml/min, although these studies, most of which are not prospective or randomized, have not provided conclusive results. Recently, Pozzi et al. demonstrated that treatment with glucocorticoids for 6 months significantly improved renal survival and proteinuria for 10 years of follow-up. A recent meta-analysis by Samuels et al. supports the use of corticosteroids in reducing proteinuria and preventing progression to end-stage renal disease. Increasing attention has been drawn to the role of tonsillectomy in the longterm prognosis of IgAN. The notion that tonsillectomy not only helps to prevent episodic macroscopic hematuria in the short-term but also gives long-term renal protection in IgAN is supported by two large retrospective studies from Japan. A study of 329 patients with IgAN by Hotta et al. found that tonsillectomy plus high-dose methylprednisolone was identified as one of the independent variables in predicting remission of clinical findings and lack of renal progression. Moreover, Xie et al. have reported that, for 20 years of follow-up, renal survival was significantly better in IgAN patients who underwent tonsillectomy than those who did not undergo the procedure. However, the role of tonsillectomy in the long-term prognosis of IgAN remains unclear, since it has not yet been tested in a controlled randomized trial. The role of mycophenolate mofetil (MMF) in IgAN has been examined in four major trials. Two prospective randomized studies report no benefit from MMF. The remaining two studies showed a greater reduction of proteinuria in patients treated with MMF compared to prednisone or placebo. In both studies, however, MMF did not effectively modify the progressive course of the disease. Thus, despite promising results in large randomized controlled trials in lupus nephritis, the evidence for the use of MMF in IgAN is inconclusive.