Serum levels of antibodies against Actinobacillus actinomycetemcomitans in various forms of human periodontitis.

Serum levels of IgG, IgA, and IgM antibodies against extracts from Bacteroides gingivalis PER8, Actinobacillus actinomycetemcomitans Y4, and Bacteroides fragilis NCTC 9343 were determined in three categories of periodontitis patients by means of enzyme-linked immunosorbent assay. The test groups comprised 10 patients with juvenile periodontitis (JP), 18 young patients with severe periodontitis (YP), and 31 patients with adult periodontitis (AP). Nine subjects with healthy periodontium (HP) served as a reference group. Increased frequencies of patients with significantly elevated IgG and IgA antibody values against B. gingivalis and A. actinomycetemcomitans were found in the three periodontitis groups as compared with the HP group. The AP group, however, showed lower IgM values than the other groups. The results support the contention that A. actinomycetemcomitans may play a contributory role in adult periodontitis and that B. gingivalis is a suspected periopathogenic bacterium in juvenile periodontitis. The clinical YP classification was not supported by the present serologic findings.