title: Th1 and Th2-like protein balance in human inflammatory radicular cysts and periapical granulomas.
abstract: BACKGROUND
  Chronic dental periapical lesions result from chronic inflammation of periapical tissues caused by continuous antigenic stimulation from infected root canals. Recent findings have suggested that T helper (Th) 1 and Th2-like cytokines are important in the pathogenesis of chronic periapical inflammatory diseases. However, the mechanisms regulating these immunoinflammatory pathways have not been fully elucidated. Thus, the aim of this study was to evaluate interleukin (IL)-4, IL-12, and interferon γ (IFN-γ) protein levels in human radicular cysts and periapical granulomas.
  
  
  METHODS
  Archived samples of cysts (n = 52) and granulomas (n = 27) were sectioned and submitted to immunohistochemistry to evaluate the tissue expression of IL-4, IL-12, and IFN-γ. The data were analyzed using the Mann-Whitney U test (P < .05).
  
  
  RESULTS
  An increased expression of IFN-γ was observed in radicular cysts. IL-4 expression was stronger in periapical granulomas than in radicular cysts. IL-12 was not detected in any of the samples.
  
  
  CONCLUSIONS
  Our study showed that IFN-γ protein levels are increased in radicular cysts, whereas IL-4 expression is stronger in samples of periapical granulomas. Further studies are necessary to elucidate the signaling pathways mediated by these cytokines and to facilitate the development of more effective periapical disease management strategies.
authors.affiliation: Department of Dentistry, Universidade Estadual de Montes Claros, Montes Claros, Brazil.
authors.forename: Carlos Alberto
authors.initials: CA
authors.lastname: de Carvalho Fraga
authors.forename: Lucas Rodrigues
authors.initials: LR
authors.lastname: Alves
authors.forename: Adriana Alkmim
authors.initials: AA
authors.lastname: de Sousa
authors.forename: Sabrina Ferreira
authors.initials: SF
authors.lastname: de Jesus
authors.forename: Daniel Nogueira
authors.initials: DN
authors.lastname: Vilela
authors.forename: Camila Santos
authors.initials: CS
authors.lastname: Pereira
authors.forename: Patrícia Luciana
authors.initials: PL
authors.lastname: Batista Domingos
authors.forename: Agostinho Gonçalves
authors.initials: AG
authors.lastname: Viana
authors.forename: Bruno Correia
authors.initials: BC
authors.lastname: Jham
authors.forename: Alfredo Maurício
authors.initials: AM
authors.lastname: Batista de Paula
authors.forename: André Luiz
authors.initials: AL
authors.lastname: Sena Guimarães
mesh_terms: D000328:Adult; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007371:Interferon-gamma / Q000378:metabolism*; D018664:Interleukin-12 / Q000378:metabolism; D015847:Interleukin-4 / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D010484:Periapical Granuloma / Q000276:immunology*; D011842:Radicular Cyst / Q000276:immunology*; D018709:Statistics, Nonparametric; D058408:Th1-Th2 Balance; D055815:Young Adult
chemical_list: D018664:Interleukin-12; D015847:Interleukin-4; D007371:Interferon-gamma