Reduced CD8+ peripheral blood T lymphocytes in rapidly progressive periodontitis

The peripheral blood T-cell phenotype of patients with rapidly progressive periodontitis (RPP) was determined in order to investigate whether there were T-cell imbalances or not. Twenty patients aged 21–39 yr were selected for this study. Bone resorption and probing pocket depth were measured. All the patients had 10 or more teeth showing bone loss of 50% or more. As controls, 12 periodontally healthy, age-matched individuals were selected. Blood samples were obtained by venipuncture, and lymphocytes were isolated. Two-colour flow cytometric analysis was done with monoclonal antibodies against human CD4, CD8, and CD45RA antigens. The RPP patients were found to have significantly lower percentage of CD8+ T cells (Mann-Whitneyʹs U-test, p < 0.01) and an increased CD4/CD8 ratio (Mann-Whitneyʹs U-test, p < 0.01) compared with healthy individuals. On the other hand, there were no significant differences in the percentages of CD4+ T cells and CD4 + CD45RA+ T cells between RPP patients and healthy individuals. No correlations between the clinical findings and T-cell subsets were found. These findings suggest that imbalances of peripheral blood T lymphocytes, especially a tendency to decreased CD8+ T cells, exist in RPP patients, and that cellular immune responses mediated by CD8+ T cells may play a part in the pathogenesis of RPP.