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

Campos, Karoline Rodrigues; Santos, Fred Luciano Neves; Brito, Vanessa Da Silva; Gonçalves, Noilson Lázaro; Araújo, Théssika Hialla Almeida; Galvão–Castro, Bernardo; Caterino–de–Araujo, Adele

doi:10.1128/jcm.01384-19

Cited by 30 publications

(42 citation statements)

References 41 publications

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“…In further efforts to solve the long-standing problem with the WB approach described above, we evaluated the LIA method, an immunoblot approach based on recombinant antigens and synthetic peptides from HTLV-1/2 Gag and Env proteins, as an alternative confirmatory test [ 21 ]. LIA is commonly used in Europe and Brazil, and has been reported to be useful for confirmatory testing of HTLV-1 infection [ 22 – 25 ]. Quite recently this assay started to be available in Japan also [ 26 ], but as HTLV-1 in Japan belongs to a Japanese subgroup within Cosmopolitan subtype A [ 36 ], the assessment using Japanese samples as an alternative confirmatory test of LIA was insufficient.…”

Section: Discussionmentioning

confidence: 99%

“…Recently, the line immunoassay (LIA) [ 21 ], which has been mainly used in Europe and Brazil as an alternative confirmatory test for HTLV-1 antibodies [ 22 – 25 ], has begun to be used in Japan [ 26 ]. Therefore, in this study, we sought to determine the current issues relating to a WB-based HTLV-1 diagnostic assay kit for Japanese samples, and to investigate the usefulness of the LIA as compared to WB for confirmation of sample reactivity.…”

Section: Introductionmentioning

confidence: 99%

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Establishment of a novel diagnostic test algorithm for human T-cell leukemia virus type 1 infection with line immunoassay replacement of western blotting: a collaborative study for performance evaluation of diagnostic assays in Japan

et al. 2020

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Background: The reliable diagnosis of human T-cell leukemia virus type 1 (HTLV-1) infection is important, particularly as it can be vertically transmitted by breast feeding mothers to their infants. However, current diagnosis in Japan requires a confirmatory western blot (WB) test after screening/primary testing for HTLV-1 antibodies, but this test often gives indeterminate results. Thus, this collaborative study evaluated the reliability of diagnostic assays for HTLV-1 infection, including a WB-based one, along with line immunoassay (LIA) as an alternative to WB for confirmatory testing. Results: Using peripheral blood samples from blood donors and pregnant women previously serologically screened and subjected to WB analysis, we analyzed the performances of 10 HTLV-1 antibody assay kits commercially available in Japan. No marked differences in the performances of eight of the screening kits were apparent. However, LIA determined most of the WB-indeterminate samples to be conclusively positive or negative (an 88.0% detection rate). When we also compared the sensitivity to HTLV-1 envelope gp21 with that of other antigens by LIA, the sensitivity to gp21 was the strongest. When we also compared the sensitivity to envelope gp46 by LIA with that of WB, LIA showed stronger sensitivity to gp46 than WB did. These findings indicate that LIA is an alternative confirmatory test to WB analysis without gp21. Therefore, we established a novel diagnostic test algorithm for HTLV-1 infection in Japan,

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Establishment of a novel diagnostic test algorithm for human T-cell leukemia virus type 1 infection with line immunoassay replacement of western blotting: a collaborative study for performance evaluation of diagnostic assays in Japan

et al. 2020

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“…Some VMFs also expressed HTLV-1 antigens and caused the de novo infection of target cells in vivo. Accordingly, it is of interest to elucidate whether the bloodplacental barrier is disrupted by the HTLV-1 infection of VTs and line immunoassays (66), the use of higher-sensitivity testing is expected to lead to a more accurate understanding of the transplacental transmission of HTLV-1.…”

Section: Discussionmentioning

confidence: 99%

HTLV-1 targets human placental trophoblasts in seropositive pregnant women

Tezuka¹,

Fuchi²,

Okuma³

et al. 2020

Journal of Clinical Investigation

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Maternal blood during pregnancy, cord blood, and placental villous tissues at the time of delivery were obtained from subjects to measure the HTLV-1 proviral load (PVL) using real-time PCR. As shown in Figure 1A, HTLV-1 provirus was detected in the maternal blood of 248 of 254 subjects (97.6%), in the placental villous tissues of 140 of 254 subjects (55.1%), and in the cord blood samples of 6 of 254 subjects (2.4%). Overall, 248 women had PVL in the maternal blood, of whom 140 also had PVL in the placenta. Of these 140 women, 6 had PVL in the cord blood. Significant differences in the PVL were observed between the maternal blood, cord blood, and placental villous tissues (Figure 1A). The 248 pregnant carriers with PVL in the maternal blood were divided into those with PVL (n = 140) and without PVL (n = 108) in the placental tissue, and their clinical backgrounds were compared. Women with PVL in the placental tissue had a significantly higher peripheral blood PVL, higher antibody titers, and more multiparas compared with women with no PVL in the placental tissue (Table 1 and Figure 1B). These 2 groups did not differ in terms of birth weight and pregnancy complications (Table 1). There was no significant difference in the clinical backgrounds of pregnant women with HTLV-1 in the placenta when divided into those who tested positive versus negative for HTLV-1 in the cord blood (Supplemental Table 1). This was at least in part due to the small number of pregnant women testing positive for HTLV-1 in the cord blood. In addition, there were insufficient numbers of follow-up surveys of cases of MTCT by intrauterine transmission to allow statistical analysis. These issues are subjects for future investigation. A weak positive correlation between the PVLs in the maternal blood and in the placental villous tissues was observed (Figure 1C), whereas PVL in HTLV-1-positive cord blood samples did not correlate with PVL in the maternal blood or placental villous tissues of the same subject (Figure 1, D and E). To test the possibility that HTLV-1 provirus detected in cord blood was derived from maternal blood contamination of cord blood, microsatellite analysis was performed using short tandem repeat (STR) markers (25). Differences in the patterns of representative STR markers were observed between maternal blood-derived DNA and fetal placental villous tissue-and cord blood-derived DNA (Figure 1F). Similar results were obtained for all 6 samples that tested positive for HTLV-1 provirus in the cord blood. Furthermore, STR analysis and HTLV-1 PVL assay were used to examine how much maternal blood in the cord blood was required to detect a positive signal. A mixing rate of 20% (maternal/fetal cell ratio = 20:80) was the detection limit in the STR analysis, and a mixing rate of 5% (maternal/fetal cell ratio = 5:95) was the detection limit in the HTLV-1 PVL assay (Supplemental Figure 1). A previous study reported that the median rates of maternal blood contamination in the cord blood were 0.27% and 0.

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“…Thus, while serological tests have high sensitivity, molecular assays stand out for their specificity and lower cost [ 25 ], which is an important feature for low and middle-income countries. However, LIA is time-consuming and has an elevated cost [ 27 ], and WB shows a prevalence of indeterminate results as high as 67% of cases [ 28 ], particularly in HTLV-2 carriers [ 26 , 29 , 30 , 31 ] and HIV/HTLV-coinfected individuals [ 27 , 32 ]. To overcome this issue, it was proposed to initially test blood samples with molecular assays, which display higher specificity, and negative samples might be further tested by WB or LIA, thus improving the cost-effectiveness of HTLV-1/2 infection diagnosis [ 25 , 33 , 34 ].…”

Section: Introductionmentioning

confidence: 99%

Loop-Mediated Isothermal Amplification (LAMP) Assay for Rapid and Accurate Confirmatory Diagnosis of HTLV-1/2 Infection

Gomes

Caterino–de–Araujo

Campos

et al. 2020

Viruses

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Laboratory diagnosis of human T-lymphotropic viruses (HTLV) 1 and 2 infection is performed by serological screening and further confirmation with serological or molecular assays. Thus, we developed a loop-mediated isothermal nucleic acid amplification (LAMP) assay for the detection of HTLV-1/2 in blood samples. The sensitivity and accuracy of HTLV-1/2 LAMP were defined with DNA samples from individuals infected with HTLV-1 (n = 125), HTLV-2 (n = 19), and coinfected with HIV (n = 82), and compared with real-time polymerase chain reaction (qPCR) and PCR-restriction fragment length polymorphism (RFLP). The overall accuracy of HTLV-1/2 LAMP (95% CI 74.8–85.5%) was slightly superior to qPCR (95% CI 69.5–81.1%) and similar to PCR-RFLP (95% CI 79.5–89.3%). The sensitivity of LAMP was greater for HTLV-1 (95% CI 83.2–93.4%) than for HTLV-2 (95% CI 43.2–70.8%). This was also observed in qPCR and PCR-RFLP, which was associated with the commonly lower HTLV-2 proviral load. All molecular assays tested showed better results with samples from HTLV-1/2 mono-infected individuals compared with HIV-coinfected patients, who present lower CD4 T-cell counts. In conclusion, HTLV-1/2 LAMP had similar to superior performance than PCR-based assays, and therefore may represent an attractive alternative for HTLV-1/2 diagnosis due to reduced working time and costs, and the simple infrastructure needed.

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

Cited by 30 publications

References 41 publications

Establishment of a novel diagnostic test algorithm for human T-cell leukemia virus type 1 infection with line immunoassay replacement of western blotting: a collaborative study for performance evaluation of diagnostic assays in Japan

Establishment of a novel diagnostic test algorithm for human T-cell leukemia virus type 1 infection with line immunoassay replacement of western blotting: a collaborative study for performance evaluation of diagnostic assays in Japan

HTLV-1 targets human placental trophoblasts in seropositive pregnant women

Loop-Mediated Isothermal Amplification (LAMP) Assay for Rapid and Accurate Confirmatory Diagnosis of HTLV-1/2 Infection

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