Relationship between gingival crevicular fluid and serum antibody titers in young adults with generalized and localized periodontitis.

The objective of the present study was to determine the relationship between concentrations of antibodies in serum and those in gingival crevicular fluid (GCF) of patients with juvenile periodontitis and severe periodontitis. Most antigens used to quantitate antibodies were obtained from a panel of bacteria associated with juvenile periodontitis or severe periodontitis. We further investigated variation in antibody titer among different periodontal sites and the extent to which antibody in GCF is locally derived. Titers of antibody, total immunoglobulin G (IgG), and human serum albumin were determined with sensitive radioimmunoassays. The relationship between serum and GCF antibody was complex. Both person-to-person variability and marked variability within the same subject were found among different sites of similar clinical status. The site-to-site variability was found not only for antibody reactive with periodontal organisms, but also for antitetanus toxoid, total IgG, and even human serum albumin. Generally the variability was in the degree of depression of the level in GCF relative to that in serum. However, anti-Bacteroides gingivalis and anti-Actinobacillus actinomycetemcomitans in GCF often exceeded the level in serum. When antibody titers in serum and GCF were calculated per milligram of human serum albumin, most of the apparent depressions of antibody in GCF disappeared. The ratio of antibody in serum to that in GCF approached unity for all organisms except B. gingivalis and A. actinomycetemcomitans Y4, which were markedly elevated. Furthermore, the level of IgG per milligram of human serum albumin in GCF was about twice the level in serum. We believe that human serum albumin reflects serum contribution to the GCF, and we therefore attribute the increased level of IgG per milligram of albumin in GCF to local synthesis. It appears that anti-B. gingivalis and anti-A. actinomycetemcomitans represent an important portion of this local antibody synthesis, since most seropositive patients with severe or juvenile periodontitis had at least one site elevated, and the magnitudes of the elevations were large in many sites. Those sites yielding elevated antibody exhibited no obvious differences in clinical parameters of probeable depth or attachment level as compared with sites in which antibody levels in GCF were similar to serum levels. Elevated antibody in GCF may relate to changes in disease activity that are not detectable by usual clinical measures.