A COMPARISON OF IGG ANTIBODY-REACTIVE WITH BACTEROIDES-FORSYTHUS AND PORPHYROMONAS-GINGIVALIS IN ADULT AND EARLY-ONSET PERIODONTITIS

RECENT WORK HAS INDICATED that Bacteroides forsythus and Porphyromonas gingivalis are significant local risk factors for periodontitis. Seve ral reports find that both organisms are frequently associated with pe riodontitis lesions and often are present together. We have previously shown that early-onset periodontitis patients seropositive for P. gin givalis have less attachment loss than seronegative patients. In this study, we determined serum IgG antibody concentrations reactive with B . forsythus in adult and early-onset periodontitis patients using an E LISA and used P. gingivalis in the same populations as a positive cont rol. The results for P. gingivalis were consistent with previous work and indicated that 47%, 36%, and 33% of adult, generalized early-onset , and localized juvenile patients were seropositive, respectively. Mea n serum IgG concentrations for the three groups were 5.36 mu g/ml, 5.6 5 mu g/ml, and 5.44 mu g/ml for adult, generalized early-onset, and lo calized juvenile patients, respectively. In contrast, for B. forsythus only 11%, 14%, and 10% of adult, generalized early-onset, and localiz ed juvenile patients were seropositive, with mean serum IgG concentrat ions of 0.46 mu g/ml, 0.46 mu g/ml, and 0.47 mu g/ml, respectively. Th is suggests that B, forsythus is either poorly immunogenic or less inv asive than P. gingivalis. If most patients fail to mount an immune res ponse to B. forsythus and it is invasive, it may explain why this orga nism is a risk factor for disease.