Histological evaluation of interleukin‐1β and collagen in gingival tissue from untreated adult periodontitis

Interleukin‐1 beta (IL‐1β) may be related to the pathological processes associated with periodontitis, primarily due to its ability to induce collagenase, increase neutrophil chemotaxis, and stimulate bone resorption. This study was designed to histologically quantitate IL‐1β positive cells from various histologic fields in untreated gingivitis/early periodontitis (G/EP) versus moderate /severe periodontitis (M/SP) gingival tissues, and associate these with collagen loss. Two gingival biopsies from 8 patients were collected, one from a G/EP site and one from a M/SP site. Mouse monoclonal antibodies in combination with an avidin‐biotin‐peroxidase system were used to stain for IL‐1β, while the van Gieson method was used to stain for collagen in serial sections. Collagen loss in G/EP (35%) and M/SP (52%) fields was consistent with gingivitis and periodontitis, respectively. IL‐1β positive cells in combined coronal/sulcular (Co/Su) and apical/sulcular (Ap/Su) fields (nearest the bacterial insult) were significantly more numerous compared to combined coronal/middle (Co/Mi) and apical/middle (Ap/Mi) fields (p < 0.05). While numbers and percentages of IL‐1β positive cells were generally higher in M/SP biopsies, differences were not significant. Further, there was no correlation between the number of IL‐1β positive cells and percent collagen loss. However, a significant correlation between IL‐1β positive cells and corresponding gingival crevicular fluid IL‐1β concentrations was noted (r = 0.65, p = 0.01). Through the use of immunohisto‐chemistry, this study demonstrated that the presence of IL‐lβ+ cells does not appear to have a direct association with collagen loss.