Type 1/type 2 Cytokine Serum Levels and Role of Interleukin-18 in Children with Steroid-sensitive Nephrotic Syndrome

Introduction: In view of the conflicting evidence of helper T cell type 1 (Th1) or type 2 (Th2) pattern of cytokine synthesis in steroid sensitive nephrotic syndrome (SSNS), this study aimed to assess type-1/type-2 cytokines level in different stages of SSNS and to evaluate the role of IL-18.

Methods: We prospectively studied thirty children with SSNS, aged 2-12 years. The children were evaluated in the active stage before treatment initiation and re-evaluated again during remission while still on steroid treatment. A subgroup of children (21/30) was also evaluated during remission after steroid withdrawal. The control group included 30 healthy age- and sex-matched siblings. Serum levels of IL-2, IFN-γ, ΙL-4, IL-13 and IL-18 were measured by ELISA.

Results: IL-2 levels were not significantly different between children in different stages of SSNS and controls (p>0.05). Levels of IL-4, IL-13 and IL-18 were significantly higher during the active stage of SSNS compared to remission and controls (p<0.05). Serum IFN-γ was significantly lower in children with active disease compared to remission stages and controls (p<0.05). In children with SSNS, serum levels of IL-18 correlated significantly with both IL-4 and IL-13 during all stages (r=0.72 and p<0.0001, r=0.82 and p<0.0001, respectively).

Conclusion: Children with active SSNS seem to have a shift to type-2 cytokine production, and IL-18 expression is significantly correlated with this type-2 immune response.