Abstract： Objective:To determine the value of serum immunoglobulin (Ig) E in predicting the treatment efficacy of steroids therapy in children with frequently relapsing nephrotic syndrome (NS) .Methods:Sixty children with nephrotic syndrome in our hospital were included in the study, comprising 30 with frequently relapsing NS (frequent relapse group) and 30 children with non-frequently relapsing NS (non frequent relapse group) . Another 30 healthy children were recruited as the control group. The frequent relapse and non frequent relapse groups were given steroids therapy after admission. On admission, serum IgA, IgE, IgG and IgM levels were detected and compared among the control group and children with NS (prior to medication) . The changes in IgE levels were compared between the two groups of children with NS. The efficacy of steroids therapy was compared in the NS children according to elevation of serum IgE. The value of serum IgE in predicting steroid resistance in children with frequently relapsing NS was analyzed by ROC curve.Results:The IgE levels showed statistically significant difference across the three groups, being highest in the frequent relapse group, followed by non frequent relapse group and control group ( P<0.05) . The levels of IgG and IgM were highest in the control group, followed by frequent relapse group and non frequent relapse group, with statistically significant difference ( P<0.05) . IgE was more likely to be elevated in the frequent relapse group than in the non frequent relapse group, with statistically significant difference ( P<0.05) . In children with frequently relapsing NS, resistance to steriods was more likely to develop in those without than those with elevated IgE ( P<0.05) . By ROC analysis, the area under the curve of IgE was 0.884 (standard error, 0.048; 95% confidence interval, 0.789 - 0.979) , with the optimal cutoff value being 99.500, a sensitivity of 0.833, and a specificity of 0.900 ( P<0.05) . Conclusion:Serum IgE is highly expressed in children with frequently relapsing nephrotic syndrome. A cutoff value of IgE>99.500 may predict high sensitivity to steroids therapy, and therefore is noteworthy to clinicians in guiding the treatment.