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

• Published in: Diagnostic microbiology and infectious disease Vol. 30; no. 3; pp. 173 - 182
• Main Authors: Caterino-de-Araujo, Adele, de los Santos-Fortuna, Elizabeth, Meleiro, Mônica Cristina Zandoná, Suleiman, Jamal, Calabrò, Maria Luisa, Favero, Anna, De Rossi, Anita, Chieco-Bianchi, Luigi
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01-03-1998; Elsevier
• Subjects: Adolescent; Adult; Aged; AIDS/HIV; Biological and medical sciences; Blotting, Western - methods; Brazil - epidemiology; DNA, Viral - isolation & purification; Enzyme-Linked Immunosorbent Assay - methods; Female; HIV Infections - complications; HTLV-I Antibodies - blood; HTLV-I Antigens; HTLV-II Antibodies - blood; HTLV-II Antigens; Human T-lymphotropic virus 1 - genetics; Human T-lymphotropic virus 1 - immunology; Human T-lymphotropic virus 1 - isolation & purification; Human T-lymphotropic virus 2 - genetics; Human T-lymphotropic virus 2 - immunology; Human T-lymphotropic virus 2 - isolation & purification; Human viral diseases; Humans; Infectious diseases; Male; Medical sciences; Middle Aged; Prevalence; Risk Factors; Sensitivity and Specificity; Viral diseases; Viral diseases of the lymphoid tissue and the blood. Aids; South America; Brazil; America; Human; Immunopathology; Mixed infection; HIV-1 virus; Retroviridae; AIDS; Method; Immune deficiency; Lentivirus; Infection; Virus; HTLV-II virus; Viral disease; Immunoblotting assay; Human immunodeficiency virus; Diagnosis; Detection; HTLV-I virus; ELISA assay
• ISSN: 0732-8893; 1879-0070
• DOI: 10.1016/S0732-8893(97)00236-8

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 IV 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.