title: Increased expression of TSH receptor by fibrocytes in thyroid-associated ophthalmopathy leads to chemokine production.
abstract: BACKGROUND
  The molecular basis for anatomically dispersed clinical manifestations in Graves' disease (GD) eludes our understanding. Bone marrow-derived, pluripotent fibrocytes represent a subset of peripheral blood mononuclear cells and infiltrate the orbital and thyroid tissues in GD. These cells may be involved in the pathogenesis of thyroid-associated ophthalmopathy (TAO).
  
  
  OBJECTIVE
  The objective of the study was to quantify fibrocyte display of functional cell surface TSH receptor (TSHR), identify the profile of chemokines they express after TSHR activation, and determine whether circulating TSHR(+) peripheral blood fibrocytes are more frequent in situ in patients with TAO.
  
  
  METHODS
  Using a newly developed technique, fibrocytes were directly identified in peripheral blood from 31 patients with TAO and 19 healthy subjects receiving care at a multidisciplinary academic center.
  
  
  METHODS
  The frequency in situ of fibrocytes (collagen 1(+), CD45(+), CD34(+), CD14(+), CD86(+) peripheral blood mononuclear cells) was assessed by multiparameter flow cytometry and correlated to clinical disease activity and smoking status. Levels of TSHR-displaying fibrocytes and their response to TSH and TSHR-activating antibody, M22, were measured by flow cytometry, Luminex, and real-time PCR.
  
  
  RESULTS
  The levels of TSHR expression by fibrocytes are substantially higher than those found in orbital fibroblasts. Moreover, the frequency of TSHR(+) fibrocytes in patients with TAO was greater than that in healthy subjects in situ. Their abundance is not influenced by disease activity or smoking history. These cells produce high levels of several cytokines and chemokines including IL-8, regulated upon activation, normal T cell expressed and secreted, and monocyte chemoattractant protein-1 when treated with TSH or M22. TSH induces IL-8 production at the pretranslational level. This induced cytokine can be detected in intact fibrocytes ex vivo.
  
  
  CONCLUSIONS
  Frequency of circulating TSHR(+) fibrocytes is markedly increased in patients with TAO, and they express proinflammatory chemokines in response to TSH. Because they infiltrate both orbit and thyroid in GD, they may represent the link between systemic immunoreactivity and organ-specific autoimmunity.
authors.affiliation: Department of Ophthalmology and Visual Sciences, University of Michigan Medical School, Kellogg Eye Center, 1000 Wall Street, Ann Arbor, Michigan 48105, USA.
authors.forename: Erin F
authors.initials: EF
authors.lastname: Gillespie
authors.forename: Konstantinos I
authors.initials: KI
authors.lastname: Papageorgiou
authors.forename: Roshini
authors.initials: R
authors.lastname: Fernando
authors.forename: Nupur
authors.initials: N
authors.lastname: Raychaudhuri
authors.forename: Kimberly P
authors.initials: KP
authors.lastname: Cockerham
authors.forename: Laya K
authors.initials: LK
authors.lastname: Charara
authors.forename: Allan C P
authors.initials: AC
authors.lastname: Goncalves
authors.forename: Shuang-Xia
authors.initials: SX
authors.lastname: Zhao
authors.forename: Anna
authors.initials: A
authors.lastname: Ginter
authors.forename: Ying
authors.initials: Y
authors.lastname: Lu
authors.forename: Terry J
authors.initials: TJ
authors.lastname: Smith
authors.forename: Raymond S
authors.initials: RS
authors.lastname: Douglas
mesh_terms: D000328:Adult; D002478:Cells, Cultured; D018932:Chemokine CCL2 / Q000378:metabolism; D018925:Chemokines / Q000096:biosynthesis*; D005260:Female; D005434:Flow Cytometry; D049970:Graves Ophthalmopathy / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D006801:Humans; D016209:Interleukin-8 / Q000378:metabolism; D007963:Leukocytes, Mononuclear / Q000187:drug effects / Q000276:immunology / Q000378:metabolism*; D008297:Male; D011989:Receptors, Thyrotropin / Q000235:genetics / Q000378:metabolism*; D013972:Thyrotropin / Q000378:metabolism / Q000494:pharmacology
chemical_list: D018932:Chemokine CCL2; D018925:Chemokines; D016209:Interleukin-8; D011989:Receptors, Thyrotropin; D013972:Thyrotropin