Elevated serum interleukin-7 level in idiopathic steroid-sensitive nephrotic syndrome.

Background: Several cytokines have a pathological association with idiopathic steroid-sensitive nephrotic syndrome (ISSNS) in inducing proteinuria or regulating T cells. Because interleukin (IL)-7 plays important roles in regulating T-cell proliferation and sustaining naïve or memory T cells, IL-7 is one of the candidate cytokines in the pathogenesis of ISSNS. Very little is known, however, about the association of IL-7 with ISSNS. To clarify the IL-7 dynamics in children with ISSNS, serum IL-7 level was investigated, from the nephrotic phase before steroid treatment (STx; group A1) to the remission phase with STx (group A2) and without STx (group A3).

Methods: Eighteen children with ISSNS were included in the present study. A total of 25 paired samples were analyzed for groups A1 and A2, and a total of 10 paired samples for groups A1, A2, and A3 due to recurrence. Two control groups (with normal urinalysis, group B; or with nephrotic syndrome other than ISSNS, group C), matched for age and gender, were also included. Serum cytokine level was measured on bead-based assay.

Results: Each serum IL-7 level in groups A1 and A3 was higher than each serum IL-7 level of groups C and B, respectively. The group A2 serum IL-7 level was higher than that of group A1. There was no statistical significance of serum IL-7 level between group A1 and group A3.

Conclusion: Serum IL-7 level was elevated in children with ISSNS regardless of the status of the disease. This brings us one step closer to a better understanding of the pathophysiology of ISSNS in children.