Abstract: Objective To investigate the role of IL-6 and IL-6R in the pathogenesis of systemic lupus erythematosus (SLE) and its clinical significance. Methods RT-PCR technique was used to semiquantitatively analyze IL-6R mRNA expression in peripheral blood mononuclear cells (PBMC), and double antibody sandwich ELISA was applied to determine the serum level of IL-6 from 89 SLE patients. Results The positive IL-6R mRNA expression was found in each individuals among active SLE group (groupⅠ), inactive SLE group (groupⅡ) and control group (group Ⅲ). The mean levels of IL-6R mRNA expressions in group Ⅰ,Ⅱ or Ⅲ were 0.902±0.273, 0.519±0.11 and 0.573±0.24, respectively. Compared with group Ⅱ and group Ⅲ, the mean level of IL-6R mRNA expression in group Ⅰ was markedly increased (P=0.00), while there was no statistical difference between group Ⅱ and group Ⅲ(P=0.289). The mean serum levels of IL-6 in group Ⅰ,Ⅱ and Ⅲ were 71.89±20.02,17.96±6.93, and 0.035±0.035, respectively. Compared with group Ⅱ and group Ⅲ, the mean level of IL-6 in groupⅠ was significantly higher than those in group Ⅱ and group Ⅲ (P=0.00), while that in group Ⅱ was higher than group Ⅲ (P=0.00). There was a positive correlation between IL-6 and IL-6R in active SLE group and inactive SLE group(r=0.887, and r=0.615 P<0.05). Conclusions The expression of IL-6R mRNA in PBMC and the serum level of IL-6 in active SLE patients are significantly higher than those in inactive SLE patients and control group. The serum level of IL-6 in inactive SLE patients is higher than that in control group. The abnormal expression of IL-6 and IL-6R might play an important role in the pathogenesis of SLE, and the level of IL-6R might be used as one of the referential indicators for active SLE.

Key words: lupus erythematosus, systemic, Interleukin-6, Receptors, interleukin-6