title: Characterization of cytokines associated with Th17 cells in the eyes of horses with recurrent uveitis.
abstract: OBJECTIVE
  Equine recurrent uveitis (ERU) is a spontaneous disease that is the most common cause of blindness in horses, affecting up to 15% of the horse population. Th17 cells are a major cell population driving the pathogenesis in several mouse models of autoimmune inflammation, including experimental autoimmune uveitis. The purpose of this study is to investigate the role a Th17 cell-mediated response plays in the pathogenesis of ERU.
  
  
  METHODS
  Banked, Davidson's-fixed equine globes histopathologically diagnosed with ERU (n = 7) were compared immunohistochemically with healthy control globes (n = 7). Immunohistochemical staining was performed using a pan-Leptospira antibody and antibodies against IL-6, IL-17, and IL-23. Additionally, immunostaining was performed for T-cell (CD3) and B-cell (CD79α) markers. Specificity of immunoreactivity was confirmed by western blot analysis.
  
  
  RESULTS
  Immunohistochemical staining was positive for IL-6, IL-17, and IL-23 within the cytoplasm of nonpigmented ciliary epithelial cells and mononuclear inflammatory cells infiltrating the iris, and ciliary body of ERU horses (n = 7) but negative in controls (n = 7). ERU-affected eyes were CD3 positive (n = 7) and CD79α negative (n = 7). Staining for Leptospira was negative in all ERU and control globes.
  
  
  CONCLUSIONS
  Strong immunoreactivity for IL-6, IL-17, and IL-23, in conjunction with the fact that T lymphocytes are the predominating inflammatory cells present in ERU, suggests that IL-17-secreting helper T-cells play a role in the pathogenesis of ERU. These findings suggest that horses with ERU may serve as a naturally occurring animal model for autoimmune uveitis.
authors: Department of Small Animal Medicine and Surgery, The University of Georgia College of Veterinary Medicine, 501 D.W. Brooks Drive, Athens, GA 30602, USA.
authors: Daniel P
authors: DP
authors: Regan
authors: Megan C
authors: MC
authors: Aarnio
authors: Wesley S
authors: WS
authors: Davis
authors: K Paige
authors: KP
authors: Carmichael
authors: Michel L
authors: ML
authors: Vandenplas
authors: James D
authors: JD
authors: Lauderdale
authors: Phillip A
authors: PA
authors: Moore
mesh_terms: D000818:Animals; D015153:Blotting, Western; D016207:Cytokines / Q000235:genetics / Q000378:metabolism*; D005123:Eye / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000502:physiology; D006734:Horse Diseases / Q000378:metabolism*; D006736:Horses; D007150:Immunohistochemistry / Q000662:veterinary; D016612:Paraffin Embedding; D058504:Th17 Cells / Q000502:physiology*; D014605:Uveitis / Q000378:metabolism / Q000662:veterinary*
chemical_list: D016207:Cytokines