title: Human T cell leukemia virus (HTLV-I/II) serodiagnostic testing: disparate results among a cohort of intravenous drug users.
abstract: Three hundred and forty-six sera collected over a 2-year period from 154 San Francisco IV drug users were subjected to HTLV-I/II RIPA, Western blot (WB), Du Pont ELISA, and p24 radioimmunoassay (RIA). Tests were performed at separate sites and code not broken until study end. RIPA-positive and -negative controls consisted of Japanese adult T cell leukemia patients, healthy blood donors, and non-IV drug-using HIV-positive men. RIPA identified HTLV-I/II-positive sera not identified by the other tests. Positive RIPAs were noted in 43% of negative ELISAs (n = 279), 34% of negative WBs (n = 243), and 40% of negative RIAs (n = 270). Seventy-two sera were negative by all 3 assays, but were RIPA positive. All sera positive by RIA (n = 76) and WB (n = 67), and 66 of 67 by ELISA, were positive by RIPA. Thirty-five of 36 indeterminate WBs were RIPA positive. Seven samples indeterminate by RIPA were negative by WB and RIA; one of seven was positive by ELISA. In all instances, samples negative by RIPA (n = 154) were ELISA, p24 RIA, and WB negative or indeterminate. We conclude that when studying HTLV-I/II-endemic cohorts, screening ELISA or RIA followed by confirmatory WB or RIPA only of seropositive samples may result in a substantial number of undetected cases. Additional studies focusing on performance characteristics of serodiagnostic tests are needed to ensure accurate inferences are made in assessing HTLV-I/II prevalence rates among high-risk groups. The RIPA may be a uniquely sensitive assay to detect HTLV-I/II gene-encoded products.
authors.affiliation: Virginia Mason Medical Center, Seattle, Washington.
authors.forename: D M
authors.initials: DM
authors.lastname: Aboulafia
authors.forename: E
authors.initials: E
authors.lastname: Feigal
authors.forename: K
authors.initials: K
authors.lastname: Vranzian
authors.forename: C
authors.initials: C
authors.lastname: Bennett
authors.forename: W
authors.initials: W
authors.lastname: Blattner
authors.forename: A
authors.initials: A
authors.lastname: Moss
authors.forename: D
authors.initials: D
authors.lastname: Slamon
mesh_terms: D000328:Adult; D000368:Aged; D015153:Blotting, Western; D015331:Cohort Studies; D015480:Deltaretrovirus Antibodies / Q000097:blood*; D006800:Deltaretrovirus Infections / Q000175:diagnosis* / Q000453:epidemiology; D004797:Enzyme-Linked Immunosorbent Assay; D005188:False Negative Reactions; D005260:Female; D005500:Follow-Up Studies; D015490:HTLV-I Infections / Q000175:diagnosis / Q000453:epidemiology; D015491:HTLV-II Infections / Q000175:diagnosis / Q000453:epidemiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D015995:Prevalence; D011863:Radioimmunoassay; D015531:Radioimmunoprecipitation Assay; D012495:San Francisco / Q000453:epidemiology; D012698:Serologic Tests / Q000379:methods*; D015819:Substance Abuse, Intravenous
chemical_list: D015480:Deltaretrovirus Antibodies