title: Preliminary assessment of Treponema pallidum-specific IgM antibody detection and a new rapid point-of-care assay for the diagnosis of syphilis in human immunodeficiency virus-1-infected patients.
abstract: The aims of the study were to assess whether Treponema pallidum-specific IgM may provide a useful marker of infectious syphilis in human immunodeficiency virus (HIV)-infected patients, and to compare the performance of a prototype IgM-rapid point-of-care test (PoCT) with a standard IgM-enzyme immunoassay (EIA). Twenty samples from HIV-infected patients with untreated syphilis (n = 4 primary syphilis, n = 11 secondary and n = 5 early latent) and 51 follow-up samples at three, six or 12 months after treatment were tested for the presence of IgM with the Mercia-EIA (Microgen Bioproducts Ltd, Camberley, UK) and a prototype PoCT (Select Vaccines Ltd, Melbourne, Australia). Although sample numbers were small, IgM detection by EIA appears to be a reliable marker for untreated syphilis in HIV-infected patients with primary (4/4 IgM-positive) or secondary syphilis (10/11 IgM-positive, 1/11 equivocal). After treatment, IgM was no longer detected after three months in the majority of patients (87%) and was either negative or equivocal in all patients after six and 12 months. The overall sensitivity of the IgM-PoCT was 82% and varied with clinical stage, being highest in secondary (10/10 EIA positives) but lower in primary (2/4 EIA positives) and early latent syphilis (2/3 EIA positives). Overall specificity was 95%. Rapid detection of IgM would enable clinicians to distinguish between past-treated and infectious syphilis and allow for diagnosis and treatment in a single visit.
authors.affiliation: Infectious Diseases Unit, Alfred Hospital, Victoria 3181,Australia. j.rotty@alfred.org.au
authors.forename: J
authors.initials: J
authors.lastname: Rotty
authors.forename: D
authors.initials: D
authors.lastname: Anderson
authors.forename: M
authors.initials: M
authors.lastname: Garcia
authors.forename: J
authors.initials: J
authors.lastname: Diaz
authors.forename: S
authors.initials: S
authors.lastname: Van de Waarsenburg
authors.forename: T
authors.initials: T
authors.lastname: Howard
authors.forename: A
authors.initials: A
authors.lastname: Dennison
authors.forename: S R
authors.initials: SR
authors.lastname: Lewin
authors.forename: J H
authors.initials: JH
authors.lastname: Elliott
authors.forename: J
authors.initials: J
authors.lastname: Hoy
mesh_terms: D000907:Antibodies, Bacterial / Q000097:blood*; D000918:Antibody Specificity; D015658:HIV Infections / Q000382:microbiology* / Q000821:virology; D015497:HIV-1 / Q000302:isolation & purification*; D006801:Humans; D007124:Immunoenzyme Techniques / Q000379:methods; D007075:Immunoglobulin M / Q000097:blood* / Q000276:immunology; D019095:Point-of-Care Systems; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D013587:Syphilis / Q000175:diagnosis* / Q000276:immunology / Q000382:microbiology / Q000821:virology; D014210:Treponema pallidum / Q000276:immunology*
chemical_list: D000907:Antibodies, Bacterial; D007075:Immunoglobulin M