ANTIBODY-REACTIVE WITH ACTINOBACILLUS-ACTINOMYCETEMCOMITANS LEUKOTOXIN IN EARLY-ONSET PERIODONTITIS PATIENTS

The objective of this study was to determine whether a relationship ex ists between antibody reactive with the Actinobacillus actinomycetemco mitans leukotoxin and the severity of periodontal disease. Serum conce ntrations of antibody reactive with the leukotoxin were determined for 119 early-onset periodontitis patients and 59 non-periodontitis subje cts using limiting dilution analysis on Western blots. Immunoglobulin G (IgG) antibody reactive with the A. actinomycetemcomitans leukotoxin ranged from undetectable to 29 mu g/ml (mean = 3.13+/-0.97 mu g/ml fo r the generalized early-onset periodontitis and 2.17+/-0.86 mu g/ml fo r the localized juvenile periodontitis patients vs 0.32+/-0.24 ng/ml f or 59 non-periodontitis controls), and the dominant subclass was IgG1. Analysis of the relationship between antibody reactive with A. actino mycetemcomitans sonicate, A. actinomycetemcomitans leukotoxin and atta chment loss patterns indicates that seropositive generalized early-ons et periodontitis patients had decreased attachment loss compared with patients lacking this antibody. The statistical relationship appeared to be stronger for the sonicate than the purified leukotoxin. These da ta suggest that antibody reactive with A. actinomycetemcomitans leukot oxin may be protective in early-onset periodontitis, but given that th e sonicate appeared better than the leukotoxin alone, it is not likely that leukotoxin is the only antigen of importance to host defense.