Immunohistologic and morphometric analysis of cytotoxic T lymphocytes in gingivitis.
BACKGROUND
Gingivitis is an inflammatory phenomenon localized in gingival tissues and histologically characterized by an infiltration of several inflammatory cell populations. The purpose of this study was to characterize, localize, and quantify in situ inflammatory and cytotoxic T lymphocytes using immunolabeled gingival tissue sections in order to specify their implication during human gingivitis, since it is well known that such cells play an important role in the defense against bacterial elements.


METHODS
Paraffin gingival tissue sections from 7 patients with gingivitis (G) and from 7 clinically and histologically healthy controls (C) were immunohistochemically stained by specific antibodies (anti-CD45, anti-CD3, anti-CD8, anti-CD20, anti-TIA-1, anti-GrB, and anti-CD68), allowing the quantification of inflammatory cells in upper gingival epithelium (Ep), in the basal epithelium layer (BEp), and in upper connective tissue (CT). Collagen fibers were stained by sirius red F3Ba in order to evaluate, by morphometric and automated image analysis, the surface occupied by collagen bundles and to histologically confirm the absence of pathology of the clinically selected healthy controls.


RESULTS
In the gingivitis group, CD45+, CD3+, CD8+, TIA-1+, and GrB+ lymphocyte numbers were significantly increased in Ep (P<0.05); and CD45+, CD3+, and TIA-I+ lymphocyte numbers were significantly increased in BEp (P <0.05) compared respectively to Ep and BEp of group C. In Ep of group G, mean CD8+/CD3+ cell ratio was significantly increased (P<0.05) compared to BEp and CT, and 25% of TIA-1+ cytotoxic cells were activated GrB+ cells.


CONCLUSIONS
The present study suggests that intraepithelial cytotoxic T lymphocytes play an important role during gingivitis and CD8 expression and that activation of TIA-1+ cytotoxic cells could be induced in Ep in response to epithelial environment. Thus, gingival epithelial tissue, which is generally only considered as a physical barrier, in fact contains numerous immune cell populations preventing the infiltration of pathogenic elements into the connective tissue. Particular clinical attention must be taken for the preservation of the epithelial tissue integrity.
Séguier
S
S
Service d'Anatomie et de Cytologie Pathologiques, Hôpital Necker-Enfants Malades, Paris, France.
Godeau
G
G
Leborgne
M
M
Pivert
G
G
Brousse
N
N
D000293:Adolescent; D000328:Adult; D017252:CD3 Complex; D016827:CD8 Antigens; D016022:Case-Control Studies; D003094:Collagen / Q000032:analysis; D004847:Epithelial Cells / Q000276:immunology; D005881:Gingiva / Q000033:anatomy & histology / Q000276:immunology; D005891:Gingivitis / Q000276:immunology*; D053804:Granzymes; D006801:Humans; D007124:Immunoenzyme Techniques; D008213:Lymphocyte Activation; D018655:Lymphocyte Count; D008565:Membrane Proteins; D008875:Middle Aged; D039102:Poly(A)-Binding Proteins; D011506:Proteins; D016601:RNA-Binding Proteins; D012697:Serine Endopeptidases; D000074019:T-Cell Intracellular Antigen-1; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*
D017252:CD3 Complex; D016827:CD8 Antigens; D008565:Membrane Proteins; D039102:Poly(A)-Binding Proteins; D011506:Proteins; D016601:RNA-Binding Proteins; D000074019:T-Cell Intracellular Antigen-1; C071558:TIA1 protein, human; D003094:Collagen; C509213:GZMB protein, human; D053804:Granzymes; D012697:Serine Endopeptidases