title: High rate of nonspecific anti-hepatitis C reactivity amongst homosexual men in comparison with that found in other sexually active groups and blood donors. Viral Hepatitis and AIDS Study Group.
abstract: OBJECTIVE
  To investigate the concordance of anti-hepatitis C virus (anti-HCV) reactivity by a second-generation enzyme immunoassay (EIA-2) and by a four-antigen recombinant immunoblot assay (4-RIBA) in homosexual men, in comparison with that found in other sexually active groups and blood donors.
  
  
  METHODS
  Prospective study.
  
  
  METHODS
  Tertiary referral centre, Seville, Spain.
  
  
  METHODS
  A total of 1203 subjects were studied. Eight hundred and three were sexually active individuals: 547 female prostitutes, 88 heterosexual men who had frequent sexual intercourse with prostitutes, and 168 homosexual men. All of them denied blood transfusion and parenteral drug use. In addition, 400 voluntary blood donors were selected at random.
  
  
  METHODS
  All serum samples were screened for anti-HCV by EIA-2 and repeatedly reactive sera were tested by 4-RIBA. Homosexual men were also screened for anti-human immunodeficiency virus (anti-HIV), hepatitis B virus (HBV) markers and gammaglobulin concentration. Finally, serum samples from homosexual men reactive for anti-HCV by EIA-2 were analyzed for HCV-RNA by polymerase chain reaction (PCR).
  
  
  RESULTS
  Concordance between EIA-2 and 4-RIBA in female prostitutes (71.4%), clients of prostitutes (75.0%), and blood donors (83.3%) was significantly higher than in homosexual men (38.8%) (P < 0.04). In this collective the concordance between 4-RIBA and PCR was 85.7% for positive cases and 88.8% for negative ones, and EIA-2 ratios in reactive sera were significantly higher in 4-RIBA confirmed cases (P < 0.0001). No correlation between false positive EIA-2 results and presence of HIV infection, HBV markers or hypergammaglobulinaemia was found in homosexual men by univariate analysis.
  
  
  CONCLUSIONS
  There is a high level of non-specific anti-HCV reactivity by EIA-2 amongst homosexual men in comparison with that found in other sexually active groups and blood donors. The true prevalence of HCV infection amongst homosexual men could be even lower than previously described.
authors.affiliation: Department of Internal Medicine, Virgen del Rocio University Hospital, Seville, Spain.
authors.forename: J
authors.initials: J
authors.lastname: Andreu
authors.forename: M A
authors.initials: MA
authors.lastname: Abad
authors.forename: A
authors.initials: A
authors.lastname: Sanchez-Quijano
authors.forename: R
authors.initials: R
authors.lastname: Torronteras
authors.forename: F
authors.initials: F
authors.lastname: Luque
authors.forename: J
authors.initials: J
authors.lastname: Garcia de las Heras
authors.forename: B
authors.initials: B
authors.lastname: Soto
authors.forename: J A
authors.initials: JA
authors.lastname: Pineda
authors.forename: M
authors.initials: M
authors.lastname: Leal
authors.forename: E
authors.initials: E
authors.lastname: Lissen
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D000956:Antigens, Viral / Q000097:blood*; D001782:Blood Donors; D005260:Female; D015488:HIV Antigens / Q000097:blood; D016174:Hepacivirus / Q000276:immunology*; D006508:Hepatitis Antibodies / Q000032:analysis; D006511:Hepatitis B Antigens / Q000097:blood; D006526:Hepatitis C / Q000453:epidemiology; D018937:Hepatitis C Antibodies; D006716:Homosexuality; D006801:Humans; D007124:Immunoenzyme Techniques; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011477:Sex Work; D005719:gamma-Globulins / Q000032:analysis
chemical_list: D000956:Antigens, Viral; D015488:HIV Antigens; D006508:Hepatitis Antibodies; D006511:Hepatitis B Antigens; D018937:Hepatitis C Antibodies; D005719:gamma-Globulins