Expression of interleukin-2 receptor and HLA-DR on lymphocyte subsets of gingival crevicular fluid in patients with periodontitis

Expression of interleukin-2 receptor (IL2R) and HLA-DR on lymphocytes of gingival crevicular fluid (GCF) was examined by two-color flow cytometric analysis. GCF from 15 patients with periodontitis was collected by crevicular washing. Mononuclear cells were isolated by Ficoll-paque gradient centrifugation from inflamed gingival tissue (GT) and peripheral blood (PB) sampled from each of the 15 patients. Lymphocyte subsets were detected by using monoclonal antibodies (mAb) of Leu 12 (CD19), Leu 4 (CD3), Leu 3a (CD4) and Leu 2a (CD8) directed to B cells, T cells, helper/inducer T cells (Th) and suppressor/cytotoxic T cells (Ts), respectively. Anti-IL2R (CD25) and anti-HLA-DR were used as lymphocyte activation markers. IL2R- or HLA-DR-positive fractions in Th, Ts and B cells were calculated. Percentage of IL2R-positive fraction in Th (IL2R+ Th) of GCF (34.0%) was significantly higher than those of GT (18.4%) and PB (13.7%). IL2R-positive fraction in B cells (IL2R+ B) of GCF was the highest among the three groups (23.9% in GCF, 12.5% in GT, 6.3% in PB). Ts did not express IL2R regardless of the origin of the samples. Compared with PB and GT, GCF showed significantly higher HLA-DR expression on Th and Ts in GCF (PB: 8.7% and 27.1%; GT: 27.9% and 50.3%; GCF: 44.7% and 65.3%). These results suggest that lymphocytes in GCF were highly activated and are related to the local host immune response in periodontitis.