Methylprednisolone pulse therapy combined with mizoribine following tonsillectomy for immunoglobulin A nephropathy: clinical remission rate, steroid sparing effect, and maintenance of renal function

The long-term prognosis of immunoglobulin A nephropathy (IgAN) is reportedly poor. In Japan, tonsillectomy-steroid pulse therapy has frequently been used for treatment of early IgAN, with favorable outcomes. However, steroid usage is sometimes limited due to adverse reactions. To reduce the total dose of steroids, we have been using mizoribine (MZR) in combination with tonsillectomy-steroid pulse therapy since 2004. Here we report a retrospective evaluation of our protocol outcome. Forty-two patients aged < 70 years with histopathologically confirmed IgAN and an estimated glomerular filtration rate (eGFR) of 30 ml/min/1.73 m(2) or higher were enrolled. After giving informed consent, all the patients underwent bilateral tonsillectomy. One week later, intravenous methylprednisolone pulse therapy (500 mg/day) was administered for 3 days, followed by oral prednisolone (30 mg/day and tapered to 0 over 7 months) and MZR (150 mg/day for 11 months). The complete remission (CR) rate and renoprotective effect were assessed. The CR rate at 6, 12, and 24 months was 33.3, 69.1, and 76.2%, respectively. Despite a relatively low total steroid dose, renal function was satisfactorily maintained for 24 months or longer with no relapse. The eGFR in patients with stage 3 chronic kidney disease was significantly improved at 6 months after start of treatment. Three patients (7.1%) had mild and transient adverse events. This protocol appears to be highly effective and safe for IgAN patients with renal dysfunction.