title: Role of circulating immune complexes in human secondary syphilis.
abstract: Studies in animal models and in the glomerulonephritis of human secondary syphilis and results from in vitro assays have suggested a role for circulating immune complexes (CICs) in human secondary syphilis. Nine adult subjects with early secondary syphilis were studied. All patients tested had CICs on C1q-binding or Raji cell assays. Proteins previously described as Treponema pallidum-specific antigens were detected by radioimmunoblot techniques in CICs from all five subjects tested. Biopsy of early cutaneous lesions revealed immunoreactants (IgG, C3, and/or C1q) in three of nine subjects and treponemal antigen in six of eight subjects tested. Histamine was injected intradermally as a trap for CICs, and biopsy of these injection sites revealed immunoreactants in four of nine subjects and treponemal antigen in five of eight subjects tested. A neutrophilic vascular reaction consistent with CIC-mediated vessel damage was seen in three of nine lesions and six of nine histamine injection sites. Normal controls did not show these changes.
mesh_terms: D000936:Antigen-Antibody Complex / Q000032:analysis*; D000942:Antigens, Bacterial / Q000032:analysis; D001808:Blood Vessels / Q000276:immunology; D003165:Complement System Proteins / Q000032:analysis; D006801:Humans; D012867:Skin / Q000098:blood supply / Q000276:immunology; D013587:Syphilis / Q000276:immunology*; D013591:Syphilis, Cutaneous / Q000276:immunology; D014210:Treponema pallidum / Q000276:immunology
chemical_list: D000936:Antigen-Antibody Complex; D000942:Antigens, Bacterial; D003165:Complement System Proteins