title: Tracking of plasma antibodies against Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis during 15 years.
abstract: BACKGROUND
  Plasma antibody measurements of antibody levels to periodontal pathogens may be used to support diagnosis, disease activity, classification, and prognosis of periodontitis.
  
  
  OBJECTIVE
  The aim of this study was to investigate the long-term stability of plasma antibody levels against Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis.
  
  
  METHODS
  Plasma immunoglobulin G (IgG) antibody levels against the pathogens were analyzed annually during 15 years from 21 voluntary subjects, whose periodontal status was not known at the point of selection. The total number of plasma samples was 315. In connection of the last sampling, the clinical and radiographic periodontal status was examined. Pooled bacterial samples from periodontal pockets, as well as salivary samples were collected for A. actinomycetemcomitans and P. gingivalis detection, and antibody determinations, respectively. According to the clinical status, six subjects had periodontitis, whereas 15 did not.
  
  
  RESULTS
  Plasma IgG-class antibody levels to periodontal pathogens remained extremely stable during the 15-year period and no significant (p>0.05) intra-individual variations were observed. Retrospectively, the average plasma IgG antibody levels against A. actinomycetemcomitans and P. gingivalis were 1.6-2.3 (p<0.05) and 1.4-1.7 (p<0.05) fold higher in the subjects with periodontitis than those without, respectively, during the whole 15-year tracking. As expected, at the time of the periodontal examination the plasma and salivary IgG antibody levels were associated both with periodontitis and bacterium-positivity.
  
  
  CONCLUSIONS
  Plasma IgG levels against A. actinomycetemcomitans and P. gingivalis are extremely stable during 15 years both in subjects with and without periodontitis.
authors.affiliation: Institute of Dentistry, University of Helsinki, Helsinki, Finland.
authors.forename: Laura
authors.initials: L
authors.lastname: Lakio
authors.forename: Johanna
authors.initials: J
authors.lastname: Antinheimo
authors.forename: Susanna
authors.initials: S
authors.lastname: Paju
authors.forename: Kåre
authors.initials: K
authors.lastname: Buhlin
authors.forename: Pirkko J
authors.initials: PJ
authors.lastname: Pussinen
authors.forename: Georg
authors.initials: G
authors.lastname: Alfthan