Infection Patterns in Chronic and Aggressive Periodontitis

Objectives: We revisited the 1999 Periodontitis Classification International Workshop postulate, according to which localized aggressive periodontitis (LAP) patients display robust serum antibody responses to infecting agents while generalized aggressive periodontitis (GAP) patients show weak responses. We further examined antibody responses in localized (LCP) and generalized chronic periodontitis (GCP) patients.

Methods: We examined 119 patients (11-76 years old; 50% male; 18 classified as LAP,  37 as GAP, 37 as LCP and  27 as GCP).  We analyzed up to 14 plaque samples/subject with respect to 11 bacterial species using checkerboard  DNA-DNA hybridization, and measured serum immunoglobulin G (IgG) levels against the same bacteria using checkerboard immunoblotting.  Bacterial and antibody data were log-transformed. To obtain a better estimate of antibody responsiveness, we calculated ‘infection ratios’ by dividing each patient’s titer with the average bacterial load for the homologous species. Comparisons between the four diagnostic categories were carried out by ANOVA and were adjusted for age and race/ethnicity.

Results: GAP patients showed the highest colonization levels by several bacterial species. IgG antibody levels to several species including Porphyromonas gingivalis, Tanerella forsythia, Treponema denticola and Campylopbacter rectus were highest in GAP and statistically significantly different from LCP and GCP, but not from LAP. Titers to Aggregatibacter actinomycetemcomitans did not differ among the four diagnostic categories.  Comparisons based on ‘infection ratios’ generally attenuated the differences between the groups, but ratios remained statistically significantly higher for T. denticola in LAP vs. LCP; for T. forsythia in LAP vs. GCP; and for Fusobacterium nucleatum in GAP vs. LCP and in LAP vs. LCP.

Conclusions: Our findings failed to corroborate the postulate of weak antibody responses in GAP patients, but rather indicated an opposite trend. Infection ratios appear to better portray the host’s responsiveness to infecting agents in periodontitis than antibody levels.

Supported by NIDCR R01-DE015649 and R00-DE 018739