title: Evidence of IL-17 producing innate lymphoid cells in peripheral blood from patients with enteropathic spondyloarthritis.
abstract: OBJECTIVE
  Both the innate and the adaptive immune responses contribute to the onset of chronic inflammation in spondyloarthritis (SpA). The association between SpA and inflammatory bowel disease (IBD, enteropathic SpA-ESpA) has been largely established and suggests a shared pathophysiology. There is evidence that innate lymphoid cells (ILC) are involved in the pathogenesis of both SpA and IBD while no evidence has been reported to date on ESpA. We aimed to analyse for the first time the frequency and cytokine expression of ILC in peripheral blood from ESpA patients compared with both IBD and healthy subjects. Correlations between immunophenotyping and disease activity were also explored.
  
  
  METHODS
  ESpA patients (n=20) were prospectively enrolled. Healthy controls (HC, n=10) and IBD patients (n=10) served as control groups. Peripheral blood Interferon (IFN)-γ and interleukin (IL)-17 expressing T and non-T cells as well as ILC subsets (ILC-1: IFN- γ +; ILC-3: IL-17+; natural killer-NK) were characterised by flowcytometry. Correlations between IL-17+ cells and SpA disease activity were analysed.
  
  
  RESULTS
  ESpA patients showed higher levels of ROR-γ expressing non T-cells with the respect to the controls. IL-17 producing non-T cells were higher than the HC and positively correlated with IFN-γ expressing cells levels as well as with SpA disease activity. ESpA showed higher levels of ILC-1 and ILC-3 than both IBD and HC. IFN-γ expressing NK cells were higher in ESpA than HC.
  
  
  CONCLUSIONS
  Our preliminary findings indicate that peripheral blood of ESpA patients is enriched for IL-17 expressing ILC which distinguishes the blood compartment from both IBD and HC. The increased IL-17 production by ILC indicates a novel role for ILC in ESpA.
authors: Rheumatology, Allergology and Clinical Immunology, Department of Medicina dei Sistemi, University of Rome Tor Vergata, Rome, Italy.
authors: Paola
authors: P
authors: Triggianese
authors: Rheumatology, Allergology and Clinical Immunology, Department of Medicina dei Sistemi, University of Rome Tor Vergata, Rome, Italy.
authors: Paola
authors: P
authors: Conigliaro
authors: Rheumatology, Allergology and Clinical Immunology, Department of Medicina dei Sistemi, University of Rome Tor Vergata, Rome, Italy.
authors: Maria Sole
authors: MS
authors: Chimenti
authors: Gastrointestinal Unit, Department of Medicina dei Sistemi, University of Rome Tor Vergata, Rome, Italy.
authors: Livia
authors: L
authors: Biancone
authors: Gastrointestinal Unit, Department of Medicina dei Sistemi, University of Rome Tor Vergata, Rome, Italy.
authors: Giovanni
authors: G
authors: Monteleone
authors: Rheumatology, Allergology and Clinical Immunology, Department of Medicina dei Sistemi, University of Rome Tor Vergata, Rome, Italy. roberto.perricone@uniroma2.it.
authors: Roberto
authors: R
authors: Perricone
authors: Gastrointestinal Unit, Department of Medicina dei Sistemi, University of Rome Tor Vergata, Rome, Italy.
authors: Ivan
authors: I
authors: Monteleone
mesh_terms: D000328:Adult; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007113:Immunity, Innate / Q000502:physiology*; D016130:Immunophenotyping; D015212:Inflammatory Bowel Diseases / Q000276:immunology* / Q000378:metabolism; D007371:Interferon-gamma / Q000378:metabolism; D020381:Interleukin-17 / Q000378:metabolism*; D008214:Lymphocytes / Q000276:immunology / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D025241:Spondylarthritis / Q000276:immunology* / Q000378:metabolism
chemical_list: D020381:Interleukin-17; D007371:Interferon-gamma