Comparative performances of serologic and molecular assays for detecting human T lymphotropic virus type 1 and type 2 (HTLV-1 and HTLV-2) in patients infected with human immunodeficiency virus type 1 (HIV-1)

Abstract

The present study evaluated several techniques currently available (commercial kits and in-house assays) for diagnosing human T lymphotropic viruses types 1 and 2 in two groups of patients enrolled at HIV/AIDS specialized care services in São Paulo: Group 1 (G1), n=1608, 1237 male/371 female, median age 44.3 years old, majority using highly active antiretroviral therapy (HAART); G2, n=1383, 930 male/453 female, median age of 35.6 years old, majority HAART naïve. Enzyme immunoassays [(EIA) Murex and Gold ELISA] were employed for human T lymphotropic viruses types 1 and 2 screening; Western blotting (WB), INNO-LIA (LIA), real-time PCR pol (qPCR), and nested-PCR-RFLP (tax) were used to confirm infection. Samples were considered human T lymphotropic viruses types 1 and 2 positive when there was reactivity using at least one of the four confirmatory assays. By serological screening, 127/2991 samples were positive or borderline, and human T lymphotropic virus infection was confirmed in 108 samples (three EIA-borderline): 56 human T lymphotropic virus type 1 [G1 (27)+G2 (29)]; 45 human T lymphotropic virus type 2 [G1 (21)+G2 (24)]; one human T lymphotropic virus type 1+human T lymphotropic virus type 2 (G2); six human T lymphotropic virus [G1 (2)+G2 (4)]. Although there were differences in group characteristics, human T lymphotropic viruses types 1 and 2 prevalence was similar [3.1% (G1) and 4.2% (G2), p=0.113]. The overall sensitivities of LIA, WB, qPCR, and PCR-RFLP were 97.2%, 82.4%, 68.9%, and 68.4%, respectively, with some differences among groups, likely due to the stage of human T lymphotropic virus infection and/or HAART duration. Indeterminate immunoblotting results were detected in G2, possibly due to the seroconversion period. Negative results in molecular assays could be explained by the use of HAART, the occurrence of defective provirus and/or the low circulating proviral load. In conclusion, when determining the human T lymphotropic virus infection, the findings highlight that there is a need to consider the blood samples with borderline results in screening assays. Of all the tested assays, LIA was the assay of choice for detecting human T lymphotropic virus type 1 and human T lymphotropic virus type 2 in human immunodeficiency virus type 1-infected patients.

HTLV‐1 and ‐2 in a first‐time blood donor population in Northeastern Brazil: Prevalence, molecular characterization, and evidence of intrafamilial transmission

“…Although both assays were shown to be equally efficient in confirming the infection with HTLV‐1, the INNO‐LIA was more efficient in diagnosing HTLV‐2 infected individuals. Similar results were reported previously, indicating that INNO‐LIA has superior performance in diagnosing HTLV‐1 and HTLV‐2 in blood donors, as well as in patients infected with HIV‐1 …”

Line Immunoassay for Confirmation and Discrimination of Human T-Cell Lymphotropic Virus Infections in Inconclusive Western Blot Serum Samples from Brazil

“…The serum samples employed in the present study were obtained from the biorepositories of the HTLV Research Laboratory (LPHTLV), Department of Immunology, Adolfo Lutz Institute (IAL), located in São Paulo, Brazil, and the Integrated and Multidisciplinary HTLV Center (CHTLV), located at the Bahiana School of Medicine and Public Health (EBMSP) in Salvador, Bahia, Brazil. Briefly, the samples from São Paulo were collected between 2012 and 2016 in the course of previous studies designed to detect the prevalence of HTLV-1/2 in HIV-infected individuals as well as in patients with hepatitis B virus (HBV) or hepatitis C virus (HCV) infection in the state of São Paulo, Brazil (14,15,(18)(19)(20). The samples from Salvador, Bahia, were obtained by routine diagnostic procedures at an outpatient clinic in Salvador (CHTLV) from 2015 to 2017; these samples were additionally used to assess the performances of four commercially available HTLV serological screening tests in Brazil (21).…”

“…Nonetheless, there was no consensus regarding the criteria to consider a blood sample truly infected by HTLV-1/2 using these techniques if positive for one or at least two DNA proviral segments of HTLV-1/2 (6,10,11). Subsequently, another molecular assay, real-time PCR or quantitative PCR (qPCR), was proposed as a confirmatory HTLV-1/2 molecular assay; however, low sensitivity was found when applied on HIV blood samples and on those from Brazilian patients infected with HTLV-2, which could be due to low HTLV-2 proviral loads (12)(13)(14)(15).…”

“…However, the high cost of INNO-LIA prevented its routine adoption in Brazil. Consequently, few studies have compared the performances of LIA and WB in Brazil, one employing blood bank samples (17) and two using serum samples from HIV/AIDS patients (14,15). These studies indicated that the LIA was the best assay to confirm or rule out HTLV-1/2 infection.…”

Increasing awareness of human T-lymphotropic virus type-1 infection: a serious, invisible, and neglected health problem in Brazil

“…Instituto Adolfo Lutz, SP, Brasil;6 Fundação Hemominas, Belo Horizonte, MG, Brasil;7 Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brasil;8 Universidade Federal do Pará, Belém, PA, Brasil;9 Universidade Federal do Alagoas, Maceió, AL, Brasil; 10 Instituto de Infectologia Emilio Ribas, São Paulo, SP, Brasil; 11 Imperial College, London, UK; 12 Universidade de São Paulo, São Paulo, SP, Brasil; 13 Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil; 14 Instituto de Infectologia Emílio Ribas, São Paulo, SP, Brasil; 15 Instituto de Medicina Tropical da Universidade de São Paulo, São Paulo, SP, Brasil; 16 Instituto de Infectologia Emilio Ribas/ Universidade de São Paulo, São Paulo, SP, Brasil; 17 Universidade Federal do Pará/ Instituto Evandro Chagas, Belém, PA, Brasil; 18 Universidade Federal do Maranhão, São Luís, MA, Brasil; 19 Fundação de Medicina Tropical Doutor Heitor Vieira Dourado, Manaus, AM, Brasil; 20 Universidade Federal do Rio Janeiro, Rio de Janeiro, RJ, Brasil; 21 Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP; Brasil; 22 Universidade Federal de Pernambuco, Recife, PE, Brasil; 23 Universidade Federal do Estado do Rio de Janeiro, Rio de Janeiro, RJ, Brasil; 24 Universidade do Estado do Rio de Janeiro, Rio de Janeiro, RJ, Brasil.…”