Preliminary clinical measurement of the expression of TNF-related apoptosis inducing ligand in patients with ankylosing spondylitis.

It has recently been reported that tumor necrosis factor (TNF)-related apoptosis inducing ligand (TRAIL) plays various roles in such autoimmune diseases as diabetes, multiple sclerosis (MS), and systemic lupus erythematosus (SLE). However, it has still remained unclear whether there is a close relationship between TRAIL and ankylosing spondylitis (AS). In this study, we investigated the association between the expression of TRAIL and AS. The specific messenger ribonucleic acid (mRNA) levels of TRAIL in peripheral blood mononuclear cells (PBMCs), serum sTRAIL, and TNF-alpha concentrations from 60 AS patients, 20 rheumatoid arthritis (RA) patients, and 30 healthy controls were determined by real-time fluorescent quantitative polymerase chain reaction (PCR) and enzyme-linked immunosorbent assay (ELISA). The results indicated that the expression levels of TRAIL mRNA, and serum sTRAIL were significantly elevated in AS patients, compared with RA patients and healthy controls, and there was a close association between TRAIL mRNA and sTRAIL levels. However, there was no significant difference between human leukocyte antigen (HLA)-B27-positive and -negative AS patients. In HLA-B27-positive patients, TRAIL mRNA and sTRAIL closely correlated with serum TNF-alpha and C-reactive protein (CRP), but did not correlate in HLA-B27-negative patients. In conclusion, upregulated expression of TRAIL might be somewhat specific for evaluation of AS.