RESUMO
PURPOSE: Determination of disease activity of lupus nephritis remains challenging. Since cytokines play a role as inflammatory mediators extending renal injury, measuring serum cytokine levels might help in the clinical assessment of patients with lupus nephritis. Therefore, the aim of this study was to determine the diagnostic value of a panel of serum cytokines in patients with active lupus nephritis. METHODS: In this prospective controlled multicenter trial, sera of 12 patients with active lupus nephritis were collected in a clinical routine setting at the time of renal biopsy and 6 months afterwards. Fourteen patients with inactive systemic lupus erythematosus (SLE), and 14 healthy subjects were used as controls. Eleven cytokines (IL-4, IL-5, IL-6, IL-10, IL-12(p40), IL-12(p70), IL-18, TNF-α, TGF-ß1, IFN-α2, IFN-γ) and two soluble receptors (IL-1ra and TNF-RII) were measured by cytokine multiplex assay. RESULTS: In inactive SLE patients, serum levels of IL-10, IL-12(p40), IL-18 and TNF-RII were increased compared to healthy controls. Active lupus nephritis was found to be associated with further increase of these cytokine levels. Follow-up measurements in clinical remission of lupus nephritis showed downregulation of increased cytokines to levels found in inactive SLE. Most strikingly, TNF-RII serum level were elevated in all patients with active lupus nephritis (p<0.001) and declined after clinical remission (p<0.0005). CONCLUSION: The cytokine multiplex assay used in our study allowed a fast and stable analysis of a panel of serum cytokines in a clinical routine setting. In addition, serum cytokines, especially TNF-RII, might be excellent markers of active lupus nephritis.