title: Phenotypically non-suppressive cells predominate among FoxP3-positive cells in oral lichen planus.
abstract: BACKGROUND
  Oral lichen planus (OLP) is a common T-cell-dominated oral chronic inflammatory disease occurring in periods of remission, quiescence, activity with pronounced inflammation, and acute ulceration. Cell infiltrates in OLP contain varying numbers of CD4+T cells expressing the transcription factor FoxP3. FoxP3+CD4+T cells are, however, a heterogeneous cell population containing suppressive and non-suppressive cells, and their distribution in infiltrates from OLP is unknown.
  
  
  METHODS
  Biopsies were taken from normal oral mucosa (n = 8) and OLP lesions (n = 19), and a set of in situ methods for the determination of the functional phenotype of FoxP3+CD4+T cells was applied.
  
  
  RESULTS
  Numbers of FoxP3+CD4+T cells were highest in the atrophic form of the disease, yet low in the ulcerative form. The main FoxP3+CD4+T-cell population observed was FoxP3+CD45RA-CD25+CD45RO+and CD15s-, a phenotype delineating a non-suppressive subset. Numbers of cells with an actively suppressing phenotype (FoxP3+CD45RA-CD25+CD45RO+and CD15s+) were, however, about twice as high in reticular lesions as compared with the atrophic form. Many FoxP3+CD4+T cells expressed T-bet, the hallmark transcription factor for IFN-γ-producing T cells, indicating that they may enhance immune and inflammatory responses rather than suppress them.
  
  
  CONCLUSIONS
  The absence of actively suppressing FoxP3+CD4+T cells may in part explain why OLP is a remarkably persisting condition, in spite of the presence of substantially high numbers of FoxP3+CD4+T cells. The findings emphasize that it is crucial to examine not only numbers but also functional phenotype of FoxP3+CD4+T cells in human tissues.
authors.affiliation: The CrossTalk Group, Department of Oral Biology, University of Oslo, Oslo, Norway. schreurs@odont.uio.no.
authors.forename: Olav
authors.initials: O
authors.lastname: Schreurs
authors.affiliation: The CrossTalk Group, Department of Oral Biology, University of Oslo, Oslo, Norway.
authors.forename: Andreas
authors.initials: A
authors.lastname: Karatsaidis
authors.affiliation: The CrossTalk Group, Department of Oral Biology, University of Oslo, Oslo, Norway.
authors.forename: Karl
authors.initials: K
authors.lastname: Schenck
mesh_terms: D000328:Adult; D000368:Aged; D015703:Antigens, CD / Q000276:immunology / Q000378:metabolism; D001706:Biopsy; D051858:Forkhead Transcription Factors / Q000276:immunology* / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D007249:Inflammation / Q000378:metabolism / Q000473:pathology; D007371:Interferon-gamma / Q000276:immunology / Q000378:metabolism; D017676:Lichen Planus, Oral / Q000276:immunology* / Q000378:metabolism / Q000473:pathology*; D008875:Middle Aged; D009061:Mouth Mucosa / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D050378:T-Lymphocytes, Regulatory / Q000276:immunology* / Q000378:metabolism; D055815:Young Adult
chemical_list: D015703:Antigens, CD; C418974:FOXP3 protein, human; D051858:Forkhead Transcription Factors; D007371:Interferon-gamma
keywords: CD15s; FoxP3; lichen planus; regulatory T cells