title: Comparison of signal-to-cutoff values in first, second, and third generation enzyme immunoassays for the diagnosis of HTLV-1/2 infection in "at-risk" individuals from São Paulo, Brazil.
abstract: Data obtained during routine diagnosis of human T-cell lymphotropic virus type 1 (HTLV-1) and 2 (HTLV-2) in "at-risk" individuals from São Paulo, Brazil using signal-to-cutoff (S/C) values obtained by first, second, and third generation enzyme immunoassay (EIA) kits, were compared. The highest S/C values were obtained with third generation EIA kits, but no correlation was detected between these values and specific antibody reactivity to HTLV-1, HTLV-2, or untyped HTLV (p=0.302). In addition, use of these third generation kits resulted in HTLV-1/2 false-positive samples. In contrast, first and second generation EIA kits showed high specificity, and the second generation EIA kits showed the highest efficiency, despite lower S/C values. Using first and second generation EIA kits, significant differences in specific antibody detection of HTLV-1, relative to HTLV-2 (p=0.019 for first generation and p<0.001 for second generation EIA kits) and relative to untyped HTLV (p=0.025 for first generation EIA kits), were observed. These results were explained by the composition and format of the assays. In addition, using receiver operating characteristics (ROC) analysis, a slight adjustment in cutoff values for third generation EIA kits improved their specificities and should be used when HTLV "at-risk" populations from this geographic area are to be evaluated.
authors.affiliation: Immunology Department, Instituto Adolfo Lutz, Coordenadoria de Controle de Doenças da Secretaria de Estado da Saúde de São Paulo, Av. Dr. Arnaldo, 355, 11 degrees andar, 01246-902, São Paulo, SP, Brazil.
authors.forename: Fabrício
authors.initials: F
authors.lastname: Jacob
authors.forename: Mariana C
authors.initials: MC
authors.lastname: Magri
authors.forename: Emanuela A S
authors.initials: EA
authors.lastname: Costa
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Santos-Fortuna
authors.forename: Adele
authors.initials: A
authors.lastname: Caterino-de-Araujo
mesh_terms: D000328:Adult; D000914:Antibodies, Viral / Q000097:blood*; D001938:Brazil; D005260:Female; D015490:HTLV-I Infections / Q000175:diagnosis* / Q000276:immunology; D015491:HTLV-II Infections / Q000175:diagnosis* / Q000276:immunology; D015368:Human T-lymphotropic virus 1 / Q000276:immunology / Q000302:isolation & purification*; D015367:Human T-lymphotropic virus 2 / Q000276:immunology / Q000302:isolation & purification*; D006801:Humans; D007124:Immunoenzyme Techniques; D008297:Male; D008875:Middle Aged; D012680:Sensitivity and Specificity; D055815:Young Adult
chemical_list: D000914:Antibodies, Viral