The current study aimed at evaluating the predictive value of serum IgG and IgG/IgM ratio measured on admission for steroid-resistant response after eight weeks of treatment in pediatric patients with idiopathic nephrotic syndrome (NS).
The current cross sectional study was conducted on 69 children, including 41 patients with idiopathic NS and 28 healthy subjects as controls. Serum IgA, IgG, and IgM levels were measured in all subjects using immunoturbidimetric method.
The median serum IgA, IgG, and IgM levels were 1.15, 2.23, and 1.7 g/L, respectively. Serum IgA and IgG levels in patients were lower than controls (P < 0.001). In addition, 46.3% of children had steroid-resistant nephrotic syndrome (SRNS). IgG had a positive predictive value for SRNS (area under the curve (AUC) = 0.923, P < 0.001). With the cutoff point of 2.04 g/L, this test had the sensitivity and specificity of 89.5% and 95.5%, respectively. The IgG/IgM ratio also had a positive predictive value for SRNS (AUC = 0.892, P < 0.001). With the cutoff point of 1.64 g/L, this test had the sensitivity of and specificity of 89.5% and 81.8%, respectively.
Serum IgG level and IgG/IgM ratio can be considered as predictive markers for steroid resistance in children first diagnosed with idiopathic NS.