Up-regulation of TRAIL mRNA expression in peripheral blood mononuclear cells from patients with active systemic lupus erythematosus

It is recently suggested that tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is involved in the pathogenesis of systemic lupus erythematosus (SLE). In this study, we examined whether expression levels of TRAIL depend on SLE activity. To estimate TRAIL mRNA expression levels in peripheral blood mononuclear cells (PBMC), we performed quantitative real-time reverse transcription-polymerase chain reaction analyses of PBMC from 18 SLE patients and 20 healthy subjects. Serum soluble TRAIL (sTRAIL) concentrations were measured by an enzyme-linked immunosorbent assay. The mean TRAIL mRNA expression level and serum sTRAIL concentration in SLE patients were significantly higher than those in healthy controls. Expression levels of TRAIL mRNA correlated with the SLE disease activity index and circulating immune complexes levels, while serum sTRAIL concentrations did not. These results indicate that increased expression of TRAIL mRNA in PBMC closely correlates with SLE activity and suggest an important role for TRAIL in the pathogenesis of SLE.