Serum level of eight cytokines in Han Chinese patients with systemic lupus erythematosus using multiplex fluorescent microsphere method

AIM OF THE STUDY: To investigate the role of 8 cytokines and their correlation with clinical characteristics in systemic lupus erythematosus (SLE) in Han Chinese population by detecting their serum levels using the multiplex fluorescent microsphere method. MATERIAL AND METHODS: Serum was separated from 79 patients with SLE and 40 healthy controls. The serum cytokine detection was conducted according to the instruction of MILLIPLEX MAP human cytokine detection kit on the Luminex liquid phase array platform with 0.01 pg/ml detectable level. The 8 cytokines were interferon α2 (IFN-α2), IFN-γ, interleukin 6 (IL-6), IL-8, IL-10, IFN-γ-inducible protein 10 (IP-10), tumor necrosis factor α (TNF-α) and IL-17. Variable data were in skewed distribution and were expressed with median (P25, P75). Mann-Whitney analysis was used in statistical analysis. RESULTS: At the baseline level without any stimulus, the level of IP-10 expression was the highest among the 8 cytokines and the second highest was IL-8. The level of IL-17 was too low to be detected. The level of 7 cytokines was higher in SLE patients than in healthy controls (p < 0.01). The level of dsDNA antibody, C3, CRP, ESR and anti-nucleosome antibody was correlated with IL-10. Proteinuria was not correlated with any cytokine. CONCLUSIONS: Eight cytokines were measured in our study, while not all of them were detected. The most important finding was the usefulness of IL-10 as a disease activity biomarker for Han Chinese patient with SLE. None of cytokines reflected kidney injury.