Systemic increase in type I interferon activity in Sjögren's syndrome: a putative role for plasmacytoid dendritic cells

Eur J Immunol. 2008 Jul;38(7):2024-33. doi: 10.1002/eji.200738008.


In the salivary glands of primary Sjögren's syndrome (pSjS) patients, type I IFN activity is increased, but systemic levels of type I IFN proteins are rarely detected. This study focused on the systemic activity of type I IFN in pSjS, as well as the role of peripheral plasmacytoid dendritic cells (pDC). Monocytes obtained from pSjS patients showed an increased expression of 40 genes. Twenty-three of these genes (58%), including IFI27, IFITM1, IFIT3 and IFI44, were inducible by type I IFN. pSjS serum had an enhanced capability of inducing IFI27, IFITM1, IFIT3 and IFI44 in the monocytic cell line THP-1, likely due to the action of IFN-beta. This effect could be inhibited by blocking the type I IFN receptor, supporting a high type I IFN bioactivity in pSjS serum. In addition, circulatory pDC showed increased expression of CD40. This expression was correlated to the expression level of the type I IFN-regulated genes IFI27 and IFITM1 in monocytes of the same individual. This study indicates that the increased type I IFN activity observed in pSjS patients is not only a local but also a systemic phenomenon and points to pDC as a possible source of this activity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • CD40 Antigens / immunology
  • CD40 Antigens / metabolism
  • Dendritic Cells / immunology*
  • Dendritic Cells / metabolism
  • Female
  • Gene Expression Profiling
  • Humans
  • Interferon Type I / blood
  • Interferon Type I / immunology
  • Interferon Type I / metabolism*
  • Middle Aged
  • Monocytes / immunology*
  • Monocytes / metabolism
  • Oligonucleotide Array Sequence Analysis
  • Salivary Glands / immunology
  • Salivary Glands / metabolism
  • Sjogren's Syndrome / immunology*
  • Sjogren's Syndrome / metabolism
  • Up-Regulation


  • CD40 Antigens
  • Interferon Type I