Serum IgG antibodies to subgingival microorganisms among adolescents with periodontitis

Objectives: Despite extensive investigation into the role of the immune response in subjects with periodontitis, little is known about the distribution of serum IgG antibodies against main putative periodontopathogens and beneficial species in cases of periodontitis among the young. Previous studies have suggested that, serum IgG antibody levels against a panel of periodontal bacteria may constitute reliable surrogate measures of clinical periodontal status among adults in epidemiological studies but it is unclear how systemic levels of IgG antibodies relate to periodontitis case status among adolescents and to the actual bacterial load in the periodontal pockets sampled.

Methods: Subgingival plaque samples were collected from six fixed sites in 87 adolescents with periodontitis and 73 non-diseased controls originating from the same underlying population. All samples were analyzed for the counts of Aggregatibacter actinomycetemcomitans, Actinomyces oris,Capnocytophaga ochracea, Campylobacter rectus, Eikenella corrodens, Fusobacterium nucleatum, Porphyromonas gingivalis, Prevotella intermedia, Parvimonas micra, Prevotella nigrescens, Streptococcus intermedius, Streptococcus mutans, Selenomonas noxia, Streptococcus oralis, Streptococcus sanguinis, Treponema denticola, Tannerella forsythia, and Veillonella parvula using the DNA–DNA hybridization technique. Serum IgG antibody levels to these species were also assessed using the checkerboard immunoassay. The mean log-transformed bacterial counts were plotted against the log transformed IgG antibody titer values to explore their relationship for cases and non-cases of periodontitis.

Results: Cases and control were of comparable age and the occurrence of smoking was similar for both groups. Cases presented with more supragingival deposits, more pocketing and more bleeding on probing than controls. The bacterial loads of putative periodontal species were higher among periodontitis cases than among the controls. However, this was not accompanied by higher IgG values. Systemic IgG values could not differentiate cases from non-cases.

Conclusions:

In this study, serum IgG antibody levels to putative periodontal pathogens cannot be considered surrogate markers of clinical periodontal status.