Histometric analysis of cell populations in gingiva with bleeding on probing by immunohistochemistry

The present study was performed by immunohistochemical methods in order to morphometrically characterize and compare the composition of cellular infiltrates in human gingivae with bleeding and non-bleeding upon probing. A total of 64 gingival biopsies (33 bleeding and 31 non-bleeding gingivae) were obtained from 23 patients. Routine Hematoxylin & Eosin and immunohistochemical stains were performed following tissue preparations. On each section, three zones were histologically divided. For each zone, the percentage and histometric analysis of plasma cells, phagocytic cells, B-cells and T-cells was calculated to characterize the composition of cellular infiltrates in gingiva associated with bleeding on probing. Significant difference was found in the middle and apical zones of infiltrated connective tissue when compared with plasma cells expressed by kappa- or lambda-chain positive immunostaining between bleeding and non-bleeding gingivae. Significant difference was also found in the coronal zone when compared with phagocytic cells and B lymphocytes between bleeding and non-bleeding gingivae. It is suggested that clinical bleeding tendency of gingiva may be highly associated with histological alterations of underlying inflammatory cell populations and a complicated immunological mechanism appears to be involved.