Expressions of IL-12 and IL-18 in blood serum and peripheral blood mononuclear cells in patients with systemic lupus erythematosus

Objective To investigate the expressions level of IL-12 and IL-18 in systemic lupus erythematosus(SLE) and their relationships with the activity of diseases.Methods The levels of IL-12 and IL-18 in blood serum and the IL-12 mRNA and IL-18 mRNA in peripheral blood mononuclear cells(PBMC) in SLE active group,SLE remission group and control group were separately measured by ELISA and semi-quantitative RT-PCR.Results The expression of IL-18 mRNA in PBMC and the level of IL-18 in blood serum of SLE active group were significantly higher than those of SLE remission group and healthy control group(all P0.05).There were significantly negative correlations between the level of IL-18 and IL-12 in blood serum(r=-0.406,P=0.019).The expressions of IL-12 mRNA and IL-12 correlated negatively with SLEDAI score(r=-0.617,P0.05;r=-0.512,P0.05).the expressions of IL-18 mRNA and IL-18 correlated positively with SLEDAI score(r=0.817,P0.05;r=0.806,P0.01).Conclusions The high expression of IL-18 and the low expression of IL-12 in SLE.IL-18 and IL-12 may play different roles in the pathogenesis of SLE.