Comparison of the Proportion of Non‐Classic (CD14+CD16+) Monocytes/Macrophages in Peripheral Blood and Gingiva of Healthy Individuals and Patients With Chronic Periodontitis

Abstract

Monocyte subsets with low CD14 expression that coexpress CD16 (CD14+CD16+) are called non-classic or hyperinflammatory monocytes. Previous studies have reported an increase in the percentage of CD14+CD16+ monocytes in the peripheral blood of patients with chronic periodontitis (CP). To our knowledge, there are no reports demonstrating the presence of CD14+CD16+ monocyte-derived macrophages (MDMs) in the gingival tissue. The objective of this study is to identify the proportion of non-classic (CD14+CD16+) monocytes/macrophages in peripheral blood and gingiva of healthy individuals and patients with CP. A total of 60 individuals (n = 30 per group) were recruited for the study. Group 1 included 30 individuals with healthy gingiva, and group 2 included 30 patients with CP. Direct immunofluorescent staining was done in 200 μL whole-blood and single-cell suspensions obtained from gingival tissue, with fluorochrome-conjugated monoclonal antibodies against CD14, CD16, and human leukocyte antigen-DR (HLA-DR), and subjected to flow cytometric analysis. The mean percentage of CD14+CD16+ monocytes in the peripheral blood of healthy individuals was 9.10% ± 1.39%, and for patients with CP it was 14.18% ± 2.69% (P <0.05). The mean percentage of CD14+CD16+ MDMs in the gingival tissue of healthy individuals was found to be 0.93% ± 0.33%, whereas in patients with CP, it was 1.92% ± 0.78% (P <0.01). Non-classic monocytes/macrophages showed a high median fluorescent intensity for HLA-DR (DR++). This study demonstrates an increased proportion of CD14+CD16+HLA-DR++ monocytes/macrophages in the peripheral blood and gingiva of patients with CP.