Antibodies to Treponema pallidum in serum from subjects with periodontitis: relationship to pathogen-related oral spirochetes.

Pathogen-related oral spirochetes were identified in dental plaque using monoclonal antibodies to putative Treponema pallidum-specific proteins, and serum from subjects with necrotizing ulcerative gingivitis contained immunoglobulin G to molecules thought to be restricted to T. pallidum. The purpose of this study was to determine whether subjects with periodontitis were more likely to have serum antibodies to T. pallidum if pathogen-related oral spirochetes were present. Pathogen-related oral spirochetes were detected in subgingival plaque from 27 of 40 subjects, and 33 subjects had serum antibodies that bound T. pallidum proteins in immunoblots. Subjects with pathogen-related oral spirochetes were no more likely to have IgA, IgG or IgM to 15-, 37- or 47-kDa proteins than were subjects without pathogen-related oral spirochetes. In contrast to subjects with necrotizing ulcerative gingivitis, subjects with periodontitis had no detectable antibodies to 37- or 12-kDa proteins. Further research is needed to identify the stimulus for antibodies that cross-react with T. pallidum proteins.