2. Children with previously diagnosed clinical idiopathic nephrotic syndrome between the age of 2-18 years at the time of diagnosis who sustain a relapse of nephrotic syndrome while off steroid therapy. A relapse is defined as a urine protein level of 2+ (100mg/dl) or greater on a first morning urine sample for 3 consecutive days. While a quantitative urine protein/creatinine ratio is more precise, this semi-quantitative definition accords with pediatric practice. Relapses will be treated according to standard clinical practice.