Immunohistological and morphometric analysis of intraepithelial lymphocytes and Langerhans cells in healthy and diseased human gingival tissues

Periodontal diseases are histologically characterized by an infiltration of several inflammatory cell populations into the gingival epithelium and con nective tissue, associated with degradation of extracellular matrix compone nts. The purpose of this in situ study was to evaluate the inflammatory sta te of gingival tissues by the number of intraepithelial lymphocyte (IEL) su bsets and the area fraction (AA%) occupied by collagen fibres in the upper gingival connective tissue, and also to evaluate the number of CD1a + Lange rhans cells (LC) in order to show correlation(s), if any, between these his tological findings. The gingival samples were from 10 clinically healthy co ntrols (group C), 8 patients with gingivitis (group G) and 9 with chronic a dult periodontitis (group P). A quantitative evaluation of the number of ce ll populations (CD1a +, CD45RB +, CD3 +, CD8 +. CD20 +, TIA-1 + and GrB + c ells) and the area fraction (AA%) occupied by collagen fibres in the upper gingival connective tissue was made by morphometric acid automated image an alysis. The results showed that, compared with group C, all IEL subset numb ers were significantly increased (p < 0.05) in G and P groups, CD20 + excep ted. In addition, there was a significant increase in the cytotoxic TIA-1 IEL nu:number (p < 0.05) in group P when compared with group G. The study also showed a significant decrease in the number of CD1a + LC in groups G a cid P (p < 0.02 and p < 0.001, respectively) when compared with group C, No significant difference was found in CD1a + LC number between groups G and P, The determination of coefficients of correlation (r) with data obtained for each patient showed that in group G, CD1a + LC number was significantly correlated with CD45RB + (p < 0.05) and CD3 + (p < 0.01) IEL numbers where as during periodontitis, CD1a + LC number was significantly and inversely c orrelated with CD20 + (p < 0.01), cytotoxic TIA-1 + (p < 0.01) and with act ivated cytotoxic GrB + (p < 0.01) IEL numbers. Moreover, in group P a signi ficant (p < 0.05) positive correlation was shown between CD1a + LC number a nd the AA% occupied by collagen fibres. This work demonstrates a decrease i n CD1a + LC number according to the severity of the periodontal disease est imated by the number of IEL and by the area fraction occupied by collagen f ibres in human gingiva. The decrease of such cells could represent a way to avoid immune overstimulation. (C) 2000 Elsevier Science Ltd. All rights re served.