title: IL-34 is overexpressed in the inflamed salivary glands of patients with Sjogren's syndrome and is associated with the local expansion of pro-inflammatory CD14(bright)CD16+ monocytes.
abstract: OBJECTIVE
  To investigate the expression of IL-34 in labial salivary glands (LSGs) of patients with primary SS (p-SS) and its role in inducing a pro-inflammatory monocyte phenotype.
  
  
  METHODS
  LSG biopsies were obtained from 20 patients with p-SS and 10 patients with non-Sjögren's sicca syndrome (n-SS). The expression of IL-34, IL-1β, TNF-α, IL-17 and IL-23 was assessed by real-time PCR. IL-34 expression was also investigated in LSGs by immunohistochemistry. The frequencies of subpopulations of CD14(+) monocytes were evaluated by flow cytometry among isolated mononuclear cells from peripheral blood and salivary glands from both patients and controls. The role of recombinant IL-34 on isolated peripheral blood mononuclear cells was also evaluated.
  
  
  RESULTS
  IL-34 m-RNA was overexpressed in the inflamed salivary glands of p-SS and associated with increased expression of TNF-α, IL-1β, IL-17 and IL-23p19. The increased expression of IL-34 was confirmed by immunohistochemistry in paraffin-embedded salivary glands from p-SS patients. IL-34 expression was accompanied by the expansion of pro-inflammatory CD14(bright)CD16(+) monocytes in the salivary glands. In vitro stimulation of peripheral blood mononuclear cells with IL-34 induced the expansion of both CD14(+)CD16(-) cells and CD14(bright)CD16(+) cells in p-SS and non-SS subjects.
  
  
  CONCLUSIONS
  IL-34 seems to be involved in the pathogenesis of salivary gland inflammation in p-SS.
authors: Dipartimento Biomedico di Medicina Interna e Specialistica, Sezione di Reumatologia, Università di Palermo, Palermo, Italy.
authors: Francesco
authors: F
authors: Ciccia
authors: Riccardo
authors: R
authors: Alessandro
authors: Vito
authors: V
authors: Rodolico
authors: Giuliana
authors: G
authors: Guggino
authors: Stefania
authors: S
authors: Raimondo
authors: Carla
authors: C
authors: Guarnotta
authors: AnnaRita
authors: A
authors: Giardina
authors: Guido
authors: G
authors: Sireci
authors: Giuseppina
authors: G
authors: Campisi
authors: Giacomo
authors: G
authors: De Leo
authors: Giovanni
authors: G
authors: Triolo
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007249:Inflammation / Q000378:metabolism / Q000473:pathology; D020381:Interleukin-17 / Q000378:metabolism; D053583:Interleukin-1beta / Q000378:metabolism; D053759:Interleukin-23 / Q000378:metabolism; D007378:Interleukins / Q000378:metabolism*; D018950:Lipopolysaccharide Receptors / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009000:Monocytes / Q000378:metabolism* / Q000473:pathology; D017452:Receptors, IgG / Q000378:metabolism*; D012469:Salivary Glands / Q000378:metabolism* / Q000473:pathology; D012859:Sjogren's Syndrome / Q000378:metabolism* / Q000473:pathology; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
chemical_list: C529076:IL34 protein, human; D020381:Interleukin-17; D053583:Interleukin-1beta; D053759:Interleukin-23; D007378:Interleukins; D018950:Lipopolysaccharide Receptors; D017452:Receptors, IgG; D014409:Tumor Necrosis Factor-alpha
keywords: Sjögren’s syndrome; interleukin-34; monocytes