Aviditätsuntersuchungen spezifischer IgG in Seren von Syphilispatienten / Investigations of avidity of specific IgG in sera of patients with syphilis

Abstract

Summary Background: Syphilis is among the infections that are characterized best by serologic methods. Nevertheless, in single cases evaluation may be difficult. The aim of this study was to investigate the avidity of specific IgG to achieve additional information. Patients and methods: In 182 previously analyzed sera from syphilitic patients the avidity of Treponema pallidum- specific IgG was estimated by means of ELISA (endpoint detection). Results: Treponema pallidum-specific IgG reached postinfectious avidity values of 20% after about four weeks and of 40% after six months without therapy. Values above 60% could be detected only in special cases. Between avidity and specific IgM–but not avidity and Cardiolipin microflocculation test -, a reverse proportional relationship exists. Persistence of specific IgM is evidenced by the avidity values. Conclusions: Avidity detection of specific IgG gives evidence of the time of primary infection. The estimation of avidity besides conventional diagnostics in syphilis may confirm cases suspected of reinfections, give additional information in problematic cases or in cases for an expert's certificate.