title: Combined analysis of monocyte and lymphocyte messenger RNA expression with serum protein profiles in patients with scleroderma.
abstract: OBJECTIVE
  We attempted to elucidate possible pathogenetic mechanisms in scleroderma by analysis of gene expression patterns of purified monocytes and lymphocytes, as well as protein profiles of cytokines and growth factors.
  
  
  METHODS
  Expression analysis was performed on messenger RNA (mRNA) from cells that had been purified with magnetic beads. Plasma samples from the same patients were used for multiplex cytokine analysis. Potential sources of proteins were also examined by in situ hybridization of skin specimens.
  
  
  RESULTS
  A total of 1,800 genes from monocytes and 863 genes from CD4+ T cells were differentially expressed in scleroderma patients. As observed by other investigators using unfractionated peripheral blood cells from patients with autoimmune connective tissue diseases, the cell type-specific analyses of our scleroderma samples showed expression of genes suggesting the presence of interferon-alpha (IFNalpha), despite the apparent absence of this cytokine in plasma. IFNalpha RNA was, however, expressed at enhanced levels in vascular and perivascular cells in scleroderma skin samples. While levels of interleukin-1alpha (IL-1alpha) and IL-16 were among 10 proteins found to be significantly elevated in scleroderma patients, none of the large panel of plasma cytokines we analyzed correlated with the expression levels of putative IFN response genes.
  
  
  CONCLUSIONS
  The pattern of up-regulation of mRNA in both the monocytes and CD4 lymphocytes of scleroderma patients, together with the detection of IFNalpha RNA in the microvasculature, suggests that leukocytes respond to this cytokine locally in the vessels. Detection of high levels of IL-1alpha and IL-16 in plasma and the independence of these protein levels from the IFN signature, implicates an independent contribution of other cytokines to immune activation and/or inflammation in scleroderma.
authors.affiliation: University of Washington, Seattle, WA 98109-4714, USA.
authors.forename: Hangjun
authors.initials: H
authors.lastname: Duan
authors.forename: Jo
authors.initials: J
authors.lastname: Fleming
authors.forename: David K
authors.initials: DK
authors.lastname: Pritchard
authors.forename: Lynn M
authors.initials: LM
authors.lastname: Amon
authors.forename: Jun
authors.initials: J
authors.lastname: Xue
authors.forename: Heather A
authors.initials: HA
authors.lastname: Arnett
authors.forename: Guang
authors.initials: G
authors.lastname: Chen
authors.forename: Patricia
authors.initials: P
authors.lastname: Breen
authors.forename: Jane H
authors.initials: JH
authors.lastname: Buckner
authors.forename: Jerry A
authors.initials: JA
authors.lastname: Molitor
authors.forename: Keith B
authors.initials: KB
authors.lastname: Elkon
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Schwartz
mesh_terms: D000328:Adult; D000368:Aged; D001798:Blood Proteins / Q000032:analysis; D005260:Female; D006801:Humans; D008214:Lymphocytes / Q000378:metabolism*; D008875:Middle Aged; D009000:Monocytes / Q000378:metabolism*; D012333:RNA, Messenger / Q000096:biosynthesis*; D045743:Scleroderma, Diffuse / Q000097:blood* / Q000235:genetics; D045745:Scleroderma, Limited / Q000097:blood* / Q000235:genetics
chemical_list: D001798:Blood Proteins; D012333:RNA, Messenger