The effects of pulse methylprednisolone (PM) therapy were studied in 15 patients (aged 3-14 years) with biopsy proven membranoproliferative glomerulonephritis (MPGN). Patients were treated with intravenous PM 30 mg/kg (max 1 g) given over 30 min every other day for a mean of 9.8 days (3-15 days). Oral prednisolone therapy was continued at a dose of 1 mg/kg/24 h for 1 month and subsequently tapered off the following month. Eight patients had hematuria and six had medically controlled hypertension. Serum C3 levels were low in 11 patients and all of the patients had proteinuria. Following PM therapy proteinuria was significantly reduced from 2602.9 +/- 1852.5 mg/24 h to 1871.2 +/- 2090.8 mg/24 h (P < 0.05) and at final evaluation, proteinuria was 774.33 +/- 1225.67 mg/24 h which was significantly lower than pre- and post-PM therapy values (P < 0.05). Serum creatinine levels were high in five patients before PM therapy and remained high in one of the patients who progressed to end-stage renal failure. After PM therapy, high serum creatinine levels normalized in three patients and was reduced, but still above normal, in one. One patient, with initially normal serum creatinine, had elevated levels afterwards. Nine of the patients were considered responsive and six non-responsive according to our tentatively defined criteria. Mean follow-up period was 27.4 +/- 24.1 months (6-84 months). Three patients were lost for follow-up, and 12 were re-evaluated.(ABSTRACT TRUNCATED AT 250 WORDS)