Sensitivity of two enzyme-linked immunosorbent assay tests in relation to western blot in detecting human T-cell lymphotropic virus types I and II infection among HIV-1 infected patients from São Paulo, Brazil.
We investigated the presence of human T-cell lymphotropic virus types I and II (HTLV-I and HTLV-II) infections, first searching for specific antibodies in 553 serum samples obtained from HIV-1-infected patients from São Paulo, Brazil. Sera were screened using two enzyme-linked immunosorbent assays (ELISAs): the ELISA-EM (ELISA HTLV-I/II, EMBRABIO, BR), which contains HTLV-I and HTLV-II lysates, and the ELISA-DB [ELISA HTLV-I/II, Diagnostic Biotechnology (DB), Singapore], which contains HTLV-I lysate, and HTLV-I and HTLV-II recombinant env proteins (MTA-1 and K55, respectively). Serum samples showing two positive and/or borderline results were confirmed by Western blot (WB 2.3, DB), which discriminates HTLV-I from HTLV-II. WB analyses disclosed 22 cases (4.0%) of HTLV-I and 34 (6.1%) of HTLV-II seroreactivity; 24 sera had indeterminate antibody profile (4.3%) and 2 specimens showed reactivity to both MTA-1 and K55 env proteins. Using stringent WB criteria and analyzing the population according to risk factors, the prevalence rates of HTLV-I and HTLV-II infections were 11.2% and 16.8% in i.v. drug users, 3.4% and 5.5% in heterosexual individuals, and 1.4% and 2.2% in homosexual/bisexual men, respectively. A comparison of ELISA and WB results disclosed that both ELISAs were highly sensitive in detecting HTLV-I antibodies, whereas the ELISA-DB showed 82% sensitivity and the ELISA-EM 100% sensitivity in detecting HTLV-II antibodies. PCR analyses conducted on 37 representative cells samples confirmed the presence of HTLV proviral DNA in the majority of concordant serological cases, except in one, which was HTLV-I infected and seroreacted with K55 protein of HTLV-II. Indeed, after PCR, one case of HTLV-I infection and HTLV-II coinfection, and 30% of WB-seroindeterminate or inconclusive cases infected with HTLV-II could be detected. Our data stress high prevalences of both HTLV-I and HTLV-II infections in HIV-1 coinfected i.v. drug users from São Paulo, and suggests that ELISA kits containing only K55 protein as the HTLV-II-specific antigen, may not have the appropriate sensitivity for the detection of HTLV-II infection in this geographic region, pointing out the need of improved screening tests to be used in Brazil.
Caterino-de-Araujo
A
A
Instituto Adolfo Lutz, São Paulo, Brazil.
de los Santos-Fortuna
E
E
Meleiro
M C
MC
Suleiman
J
J
Calabrò
M L
ML
Favero
A
A
De Rossi
A
A
Chieco-Bianchi
L
L
D000293:Adolescent; D000328:Adult; D000368:Aged; D015153:Blotting, Western / Q000379:methods*; D001938:Brazil / Q000453:epidemiology; D004279:DNA, Viral / Q000302:isolation & purification*; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D005260:Female; D015658:HIV Infections / Q000150:complications*; D015481:HTLV-I Antibodies / Q000097:blood; D015486:HTLV-I Antigens; D015482:HTLV-II Antibodies / Q000097:blood; D015487:HTLV-II Antigens; D015368:Human T-lymphotropic virus 1 / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification*; D015367:Human T-lymphotropic virus 2 / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012307:Risk Factors; D012680:Sensitivity and Specificity
D004279:DNA, Viral; D015481:HTLV-I Antibodies; D015486:HTLV-I Antigens; D015482:HTLV-II Antibodies; D015487:HTLV-II Antigens