title: Analysis of Interleukin 17A in periapical abscess and granuloma lesions.
abstract: Interleukin 17A (IL-17A) is a proinflammatory cytokine responsible for the initiation and propagation of inflammation. One of its actions is the recruitment of neutrophils to the site of infection. The aim of this study was to investigate whether there is association between IL-17A expression and neutrophil infiltration in periapical abscesses and periapical granulomas, as well as to find which type of T lymphocyte effector (CD4+ or CD8+) expresses IL-17A in these lesions. Elastase, CD4, CD8, and IL-17A were analyzed by immunohistochemistry and immunofluorescence, in the biopsies of periapical lesions. Abscess lesions exhibited the highest labeling area for IL-17A (p = 0.011). During double immunofluorescence staining, there were significantly more CD4+/IL-17A+ cells compared to CD8+/IL-17A+ cells, both in the abscesses (p = 0.025) and granulomas (p = 0.011). In conclusion, IL-17A was intensively expressed in periapical abscesses rich in neutrophils. The high percentage of IL-17A in these cases suggests the participation of this cytokine particularly in the acute stages of the inflammatory process of the periapical lesions.
authors.affiliation: Department Stomatology, School of Dentistry, Universidade de São Paulo, São Paulo, SP, Brazil.
authors.forename: Luciana Gonçalves Valente
authors.initials: LG
authors.lastname: Ferreira
authors.affiliation: Department Stomatology, School of Dentistry, Universidade de São Paulo, São Paulo, SP, Brazil.
authors.forename: Flávia Cristina Perillo
authors.initials: FC
authors.lastname: Rosin
authors.affiliation: Department Stomatology, School of Dentistry, Universidade de São Paulo, São Paulo, SP, Brazil.
authors.forename: Luciana
authors.initials: L
authors.lastname: Corrêa
mesh_terms: D001706:Biopsy; D015704:CD4 Antigens / Q000032:analysis; D015496:CD4-Positive T-Lymphocytes / Q000737:chemistry / Q000473:pathology; D016827:CD8 Antigens / Q000032:analysis; D018414:CD8-Positive T-Lymphocytes / Q000737:chemistry / Q000473:pathology; D005455:Fluorescent Antibody Technique; D006801:Humans; D007150:Immunohistochemistry; D020381:Interleukin-17 / Q000032:analysis*; D020556:Neutrophil Infiltration; D010196:Pancreatic Elastase / Q000032:analysis; D010482:Periapical Abscess / Q000378:metabolism* / Q000473:pathology; D010484:Periapical Granuloma / Q000378:metabolism* / Q000473:pathology*; D012016:Reference Values
chemical_list: D015704:CD4 Antigens; D016827:CD8 Antigens; D020381:Interleukin-17; D010196:Pancreatic Elastase