In a previous trial the investigators found that the effect of steroids in IgA nephropathy diminish over time. The difference in renal survival is striking up till the third year, but then remains constant. A six-month course of steroid therapy may be not enough to ensure a stable remission. The investigators hypothesized that a more aggressive treatment may obtain long-term better results. The investigators conducted a randomised controlled trial to assess the utility of low-dose azathioprine added to steroids in adult IgAN patients.