title: Lymphocyte numbers and function in relation to periodontitis and smoking.
abstract: BACKGROUND
  T and B lymphocytes play important roles in periodontitis. Smoking is considered a risk factor for periodontitis and may exert its negative effects through leukocytes. Taking smoking into consideration, the aim of this study was to analyze numbers of circulating T (CD3+) cells and their CD4+ and CD8+ subpopulations, B (CD19+) cells, and T-cell proliferative capacity in periodontitis.
  
  
  METHODS
  Lymphocyte immunophenotyping for T cells, their CD4+ and CD8+ subsets, and B cells was performed on peripheral blood from 76 periodontitis patients and 36 controls. Proliferative capacity of T cells was determined in whole-blood lymphocyte culture assays after mitogenic stimulation.
  
  
  RESULTS
  Total T cells, CD4+ and CD8+ subpopulations, and responsiveness to specific T-cell stimuli did not differ between patients and controls; in addition, B cells were not significantly elevated in periodontitis patients. However, more periodontal breakdown in smoking patients was associated with higher numbers of CD3+ T cells, as well as with CD4+ and CD8+ T-cell subsets, and increased T-cell proliferation. Numbers of B cells were not affected by smoking.
  
  
  CONCLUSIONS
  The increased numbers of T-cells and elevated T-cell responsiveness in patients who smoke may be one of several explanations why smoking is a risk factor for periodontitis. The mechanism of how T-cell function contributes to increase the severity of periodontal breakdown in smoking periodontitis patients needs to be investigated further.
authors.affiliation: Department of Periodontology, Academic Center for Dentistry Amsterdam, Amsterdam, The Netherlands. B.G.Loos@acta.nl
authors.forename: Bruno G
authors.initials: BG
authors.lastname: Loos
authors.forename: Marijke T L
authors.initials: MT
authors.lastname: Roos
authors.forename: Peter Th A
authors.initials: PT
authors.lastname: Schellekens
authors.forename: Ubele
authors.initials: U
authors.lastname: van der Velden
authors.forename: Frank
authors.initials: F
authors.lastname: Miedema
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D018941:Antigens, CD19; D001402:B-Lymphocytes / Q000276:immunology*; D017252:CD3 Complex; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D016022:Case-Control Studies; D016009:Chi-Square Distribution; D005260:Female; D006801:Humans; D016130:Immunophenotyping; D008213:Lymphocyte Activation; D018655:Lymphocyte Count; D008297:Male; D010518:Periodontitis / Q000097:blood / Q000209:etiology / Q000276:immunology*; D010835:Phytohemagglutinins / Q000276:immunology; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects / Q000097:blood / Q000276:immunology*; D016176:T-Lymphocyte Subsets / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D018941:Antigens, CD19; D017252:CD3 Complex; D010835:Phytohemagglutinins