Decreased levels of soluble receptor for advanced glycation end products in patients with primary Sjögren's syndrome.

The purpose of this study was to evaluate the levels of sRAGE in primary Sjögren's syndrome (SS), and to assess whether there is an association between sRAGE levels and disease characteristics. Thirteen patients were randomly selected from three subgroups: primary SS, (n = 6), secondary Sjögren's, (n = 4), and ANA(+) but lacking criteria for further disease classification (n = 3). Levels of serum sRAGE were measured in triplicate using an enzyme-linked immunosorbent assay kit. Mean sRAGE levels were significantly lower in the primary Sjögren's group. Logistic regression analysis indicated that plasma sRAGE level was a significant predictor of diagnostic status. Analyses using routine serological tests for diagnosing autoimmune disorders failed to reach statistical significance. This preliminary study supports the hypothesis that the RAGE system might participate in the disease pathway of primary SS, and that sRAGE may be a potential biomarker to aid in the diagnosis of primary SS.