[Clinical significance of the change in serum IgG titers respond to Aggregatibacter actinomycetemcomitans in chronic periodontitis patients].

OBJECTIVE

To characterize serum antibody response to Aggregatibacter actinomycetemcomitans (Aa) serotype c in chronic periodontitis (CP) patients, and to observe the correlation of IgG titer with clinical parameters.

METHODS

Venous blood samples were collected from 30 CP patients and 45 periodontal healthy controls, and unstimulated whole saliva and pooled subgingival plaque samples of CP patients were also collected for detection of Aa (PCR method). Serum IgG titers to Aa were measured by Enzyme-Linked Immunosorbent Assay (ELISA).

RESULTS

The detection rates of serum IgG to Aa serotype c in CP patients and healthy controls were both 100%. CP patients exhibited significantly higher IgG titers to Aa serotype c than healthy controls [(10.9+/-1.9) vs (9.1+/-1.8), P=0.000], and the prevalence of high-responding patients in CP group was also significantly higher than that of healthy controls (23.3% vs 0%, P=0.003). Serum IgG titers to Aa serotype c in Aa-positive CP patients (Aa-positive in subgingival plaque or saliva, n=7) were significantly higher than those of Aa-negative patients [(12.6+/-1.6) vs (10.4+/-1.7), P=0.005)]. Serum IgG titers to Aa in CP patients tended to be positively related to mean probing depth of whole mouth (r=0.344, P=0.068).

CONCLUSION

Serotype c was the main serotype of Aa in CP patients. Serum IgG antibody to Aa serotype c did not seem to have a protective effect against periodontal infection.