Serum IP-10 is useful for identifying renal and overall disease activity in pediatric systemic lupus erythematosus.

Abstract

Traditional serological biomarkers often fail to assess systemic lupus erythematosus (SLE) disease activity and discriminate lupus nephritis (LN). The aim of this study was to identify novel markers for evaluating renal and overall disease activity in Chinese patients with pediatric systemic lupus erythematosus (pSLE). The study included 46 patients with pSLE (35 girls, 11 boys; average age 13.3 ± 2.6years) and 31 matched healthy controls (22 girls, 9 boys; average age 12.3 ± 2.4years). The SLE Disease Activity Index (SLEDAI) and renal SLEDAI were used to assess disease activity. Nine different soluble mediators in plasma, including tumor necrosis factor alpha (TNF-α), platelet-derived growth factor-BB (PDGF-BB), interferon (IFN) gamma inducible protein 10 (IP-10), interleukin (IL)-1β, IFN-γ, IL-17A, IL-2, Fas and Fas ligand, were measured by Luminex assay and compared between patients with active and inactive pSLE as well as between patients with pSLE with active and inactive renal disease. Receiver operating characteristic curve analysis was used to measure the discrimination accuracy. Of the 46 patients with pSLE, 30 (65.2%) had LN. These patients had significantly elevated levels of serum TNF-α, PDGF-BB, IP-10 and Fas. The serum levels of IP-10 were also significantly higher in patients with active pSLE. We found that IP-10 was also more sensitive and specific than conventional laboratory parameters, including anti-double-stranded DNA and complement components C3 and C4, for distinguishing active lupus from quiescent lupus. The serum level of IP-10 was also significantly increased in children with pSLE with active renal disease relative to those with inactive renal disease. There was also a positive correlation between serum IP-10 levels and renal SLEDAI scores as well as with 24h urine protein. Serum IP-10 is useful for identifying renal and overall disease activity in children with pSLE.