title: Activation of the interferon pathway in peripheral blood of patients with Sjogren's syndrome.
abstract: OBJECTIVE
  DNA microarray analysis and quantitative real-time polymerase chain reaction (PCR) were performed to identify key target genes in peripheral blood from patients with Sjögren's syndrome (SS).
  
  
  METHODS
  DNA microarray analysis was performed in 19 patients with SS (all women) and 10 healthy controls (5 men and 5 women) using a low-density DNA microarray system with 778 genes. For confirmation, the expression of upregulated genes was analyzed by quantitative real-time PCR in another 37 SS patients (35 women and 2 men) and 9 healthy controls (8 women and 1 man). Relationships between gene signatures and various clinical measures, such as disease duration, symptoms and signs, complications, immunological findings, and salivary and lacrimal functions, were analyzed.
  
  
  RESULTS
  Interferon-α (IFN-α)-inducible protein 27 (IFI27) showed the most significant difference between SS patients and controls in the microarray screening. We performed quantitative RT-PCR for IFI27. IFI27 gene expression level was increased in patients with SS compared with controls (p < 0.01) by real-time PCR, supporting our observations from the microarray data. The level of IFI27 was significantly correlated with serum IgG levels (r = 0.462, p < 0.01) and ß(2)-microglobulin (r = 0.385, p < 0.05), soluble interleukin 2 receptor (r = 0.473, p < 0.01), erythrocyte sedimentation rate (r = 0.333, p < 0.05), and antinuclear antibody titer (speckled pattern; r = 0.445, p < 0.01).
  
  
  CONCLUSIONS
  Our results suggest that upregulation of IFN-inducible genes in SS patients is a systemic phenomenon, and IFN may play an important role in the pathogenesis of SS. The expression level of IFI27 could be an effective and specific biomarker associated with SS.
authors.affiliation: Third Department of Internal Medicine, Hamamatsu University School of Medicine, 1-20-1, Handayama, Higashi-ku, Hamamatsu 431-3192, Japan. kimoto@hama-med.ac.jp.
authors.forename: Osamu
authors.initials: O
authors.lastname: Kimoto
authors.forename: Jin
authors.initials: J
authors.lastname: Sawada
authors.forename: Kumiko
authors.initials: K
authors.lastname: Shimoyama
authors.forename: Daisuke
authors.initials: D
authors.lastname: Suzuki
authors.forename: Satoki
authors.initials: S
authors.lastname: Nakamura
authors.forename: Hideharu
authors.initials: H
authors.lastname: Hayashi
authors.forename: Noriyoshi
authors.initials: N
authors.lastname: Ogawa
mesh_terms: D000368:Aged; D005260:Female; D015870:Gene Expression; D006801:Humans; D007372:Interferons / Q000235:genetics* / Q000276:immunology; D008297:Male; D008565:Membrane Proteins / Q000235:genetics* / Q000276:immunology; D008875:Middle Aged; D020411:Oligonucleotide Array Sequence Analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012859:Sjogren's Syndrome / Q000235:genetics* / Q000276:immunology; D018709:Statistics, Nonparametric
chemical_list: C406887:IFI27 protein, human; D008565:Membrane Proteins; D007372:Interferons