Th2 cells predominate in idiopathic steroid-sensitive nephrotic syndrome

Various studies reported a higher incidence of allergic disorders, with an overreactivity of type 2 helper T-cell (Th2) immune mechanisms, in children with idiopathic steroid-sensitive nephrotic syndrome (ISSNS). However, Th2 predominance in ISSNS has not been definitively identified. To determine whether Th2 was predominant in children with ISSNS, we used paired samples to measure the type 1 helper T-cell (Th1)/Th2 ratios and serum cytokine levels secreted by Th1 and Th2. We measured the Th1/Th2 ratios and levels of Th1- or Th2-secreted cytokines in paired samples. Fourteen children met the inclusion criteria: (1) ISSNS; (2) selectivity index < 0.1; (3) sera obtained in at least two disease phases; (4) no infection; (5) no immunosuppressants. Two control groups (group B, normal urinalysis; group C, nephrotic syndrome other than ISSNS) were included for cytokine level comparisons. Th1 and Th2 numbers were counted by three-color flow cytometry. Cytokine levels were measured by bead-based assay. The Th1/Th2 ratio was lower in group A-1 [nephrotic-phase before steroid treatment (STx)] than in groups A-2 (remission-phase with STx) and A-3 (remission-phase without STx). Th2-secreted interleukin-5 (IL-5) levels were higher in group A-1 than in groups A-2 and A-3. There were no differences in IL-5 levels between groups A-1 and C and between groups A-3 and B. Our results suggest that Th2 played a predominant role both in the Th1/Th2 ratio and in the serum IL-5 level in children with ISSNS in the nephrotic phase.