title: False-positive reaction between syphilis and hepatitis C infection.
abstract: There are limited data about false-positive reactions against hepatitis C virus (HCV) in syphilitic patients and false-positive reactions against syphilis in the patients with HCV infection. The aim of this study was to demonstrate the false-positivity of syphilis in patients with HCV infection, the false-positivity of anti-HCV in patients with syphilis and the validity of the serological tests in such patients. Fifty patients with positive anti-HCV, 21 patients with positive VDRL and 50 healthy subjects were studied. Syphilis serology was determined by the Venereal Disease Research Laboratory (VDRL) test and microhemagglutination for T. pallidum (MHA-TP) test. Hepatitis C serology was determined by a second generation ELISA (Ortho Diagnostics) test for HCV antibody, and anti-HCV positive patients were tested for HCV RNA by polymerase chain reaction (PCR). All assays were performed on all subjects. Not only the false-positive VDRL reaction in the patients with HCV infection but also false-positive anti-HCV tests in syphilitic patients have been observed. Four patients with syphilis had positive anti-HCV and negative HCV-RNA, whereas 10% (5 of 50) of patients with hepatitis C infection had positive VDRL and these patients were negative for MHA-TP test. The rates of false-positivity of VDRL and anti-HCV were higher than within the control group (p < 0.05). According to these data, positive anti-HCV in syphilitic patients and positive VDRL in chronic hepatitis C may be false-positive results with regard to the reaginic tests. Therefore, therapeutic measures should not be initiated without confirmation with a treponemal test or PCR. VDRL and HCV-ELISA tests may be interacted with IgM or IgG antibodies. This relationship should be investigated in further studies.
authors.affiliation: Department of Infectious Diseases, Turgut Ozal Medical Center, Malatya, Turkey.
authors.forename: E
authors.initials: E
authors.lastname: Sonmez
authors.forename: I H
authors.initials: IH
authors.lastname: Ozerol
authors.forename: M
authors.initials: M
authors.lastname: Senol
authors.forename: N
authors.initials: N
authors.lastname: Kizilkaya
authors.forename: K
authors.initials: K
authors.lastname: Sahin
authors.forename: H
authors.initials: H
authors.lastname: Ozbilge
mesh_terms: D000328:Adult; D000942:Antigens, Bacterial / Q000097:blood; D016022:Case-Control Studies; D004797:Enzyme-Linked Immunosorbent Assay; D005189:False Positive Reactions; D005260:Female; D006386:Hemagglutination Tests; D016174:Hepacivirus / Q000235:genetics / Q000276:immunology; D006526:Hepatitis C / Q000175:diagnosis* / Q000276:immunology; D018936:Hepatitis C Antigens / Q000097:blood; D006801:Humans; D008297:Male; D016133:Polymerase Chain Reaction; D012367:RNA, Viral / Q000032:analysis; D015203:Reproducibility of Results; D013587:Syphilis / Q000175:diagnosis* / Q000276:immunology; D014210:Treponema pallidum / Q000276:immunology
chemical_list: D000942:Antigens, Bacterial; D018936:Hepatitis C Antigens; D012367:RNA, Viral