A novel high-performance rapid screening test for the detection of total HTLV-I and HTLV-II antibodies in HTLV-I/II infected patients.

Rapid diagnosis of human T-cell lymphotropic virus (HTLV) type-I and -II infections are essential for timely and cost-effective disease interventions. MP Diagnostics ASSURE HTLV-I/II Rapid Test was developed for the rapid detection of anti-HTLV-I/II antibodies in patients' serum, plasma, and whole blood specimens. ASSURE HTLV-I/II Rapid Test employed MP Biomedicals' proprietary HTLV-I/II Trifusion recombinant antigen conjugated with gold nanoparticles and HTLV-I / HTLV-II recombinant antigens immobilized on the nitrocellulose membrane to detect total HTLV-I and HTLV-II antibodies. The overall performance of the ASSURE HTLV-I/II Rapid Test was found to be 99.42% sensitivity (95% Confidence Interval, 98.32-99.88%) and 100% specificity (95% Confidence Interval, 99.58-100.00%) in the tested clinical samples, including a total of 518 HTLV-I/II positive specimens (396 HTLV-I infection, 97 HTLV-II infection and 25 HTLV-I/II dual infection) and 872 HTLV negative clinical specimens consisting of 691 healthy donor samples, 116 potentially cross-reactive samples, and 65 samples with interfering substances. The ASSURE HTLV-I/II Rapid Test can effectively be deployed as a screening tool in any prevalence studies, blood banks or organ transplant centres.

Trend in seroprevalence of HTLV-1/2 in Taiwanese blood donors-A 10-year follow-up.

OBJECTIVES: This study evaluated the Human T-lymphotropic virus (HTLV) screening policy impact on the HTLV seroprevalence from 2009 to 2018 as well as the differences between administrative districts in terms of prevalence distribution in Taiwan. BACKGROUND: Since February 1996, the Taiwan Blood Services Foundation (TBSF) had conducted HTLV screening of blood donors. The HTLV seroprevalence was 0.032% in 1999. MATERIALS AND METHODS: This cross-sectional study included donors' data collected from blood donation centres across Taiwan from 2009 to 2018. Enzyme immunoassay and Western blot assay were used for screening and confirmation of HTLV infections. In this study, the researchers calculated the trends in the HTLV rates of first-time and repeat donors across time as well as the HTLV prevalence distribution across the 22 administrative districts of Taiwan. RESULTS: Amongst 17 977 429 employed blood donations, 739 HTLV-seropositive donations (4.11 per 100 000 donations) were identified. The HTLV-positive donors were aged between 17 and 64 years, with a median age of 49 years. The overall seropositivity rates of first-time and repeat donors were 34.36/100 000 and 1.27/100 000. HTLV seroprevalence in first-time blood donors significantly decreased by 57% (crude odds ratio [95% confidence interval] (crude OR [95% CI]) = 0.43 [0.28-0.64]) within 10 years. A slight decline was also identified in repeat donors (crude OR [95% CI] = 0.73 [0.4-1.32]). Donors from different districts showed significantly varied prevalence. Most districts with high prevalence are situated in eastern Taiwan, for both donation types. Older blood donors were more likely to be infected with HTLV than younger ones in first time and repeat donors. Middle age donors (50-65 years) had an 18.47-39.65 greater risk than those aged <20 years. Significant higher risk of female was observed in both donation types. Amongst different age groups, first-time female donors increase 1.31-1.88 times infection risk and female in repeat donor group had 1.55-3.43 times greater risk. CONCLUSION: Over years of implementation of the HTLV blood donor screening policy by the TBSF, the HTLV seroprevalence of first-time donors has decreased consistently. Moreover, the HTLV seroprevalence of repeat donors has dropped considerably. This implies that the screening policy provides continued benefit. Females and older blood donors were more likely infected with HTLV than males and younger blood donors. The influence of age on infection was greater amongst first-time donors than amongst repeat donors. Therefore, appropriate measures should be taken to ensure public safety.

Diagnostic accuracy of Abbott Architect Assay as a screening tool for human T-cell leukaemia virus type-1 and type-2 infection in a London teaching hospital with a large solid organ transplant centre.

AIM: In the United Kingdom, organ donors/recipients are screened for evidence of human T-cell leukaemia virus type-1 and type-2 (HTLV-1/2) infections. Since the United Kingdom is a low prevalence country for HTLV infections, a screening assay with high sensitivity and specificity is required. Samples with repeat reactivity on antibody testing are sent to a reference lab for confirmatory serological and molecular testing. In the case of donor screen, this leads to delays in the release of organs and can result in wastage. We aim to assess whether a signal/cut-off (S/CO) ratio higher than the manufacturer's recommendation of 1.0 in the Abbott Architect antibody assay is a reliable measure of HTLV-1/2 infection. METHODS: We conducted a 5 year retrospective analysis of 7245 patients from which 11 766 samples were tested on the Abbott Architect rHTLV I/II assay. Reactive samples (S/CO >1) were referred for confirmatory serological and molecular detection (Western Blot and proviral DNA) at UK Health Security Agency, (formerly PHE, Colindale), the national reference laboratory. Electronic, protected laboratory and hospital patient databases were employed to collate data. RESULTS: A total of 45 patients had initially reactive samples. 42.2% (n = 19/45) had an S/CO ratio > 20, with HTLV infection confirmed in n = 18/19 and indeterminate confirmatory results in n = 1/19. No samples with an S/CO ratio <4 (48.9%, n = 22/45) or 4-20 (8.9%, n = 4/45) had positive confirmatory results on subsequent confirmatory testing. CONCLUSION: Samples with an S/CO >20 likely represent a true HTLV-1/2 infection. Reactive samples with an S/CO <4 were unlikely to confirm for HTLV infections. Interpretation of these ratios can assist clinicians in the assessment of low reactive samples and reiterates the need for faster access to confirmatory testing.

Development of a nested real time PCR/high resolution melting assay for human T-cell lymphotropic viruses types 1 and 2 (HTLV-1 and 2) identification.

HTLV-1 and HTLV-2 are present in different high-risk populations, such as sexual workers and injecting drug users (IDUs). HTLV-1 is endemic in areas of Middle East, Southern Japan and Latin America, whereas HTLV-2 infection is endemic among some Native Americans and some Central African tribes. The pathogenic consequences and clinical manifestations of these two viruses differ significantly, demanding an adequate identification; therefore, proper diagnosis of HTLV-1 and 2 infection is crucial. To get a final diagnosis of HTLV-1 or 2 infection, it is recommended that positive serologic samples should be confirmed by PCR assays or western blot (WB) analysis. Thus, the aim of this study was to develop and implement a simple reaction for the rapid identification of HTLV-1 and 2. Nested real-time PCR technique followed by high resolution melting was performed based on the tax/rex sequences of HTLV-1 (M2) and HTLV-2 (MoT) cell lines perfectly discriminating between HTLV-1 from HTLV-2, by distinct melting curve profiles. The sensitivity assay of this method revealed that at least 1 viral copy of HTLV-1 or 1·5 viral copy of HTLV-2 could be amplified. Later, this method was validated using 200 blood samples from corpses. In agreement with previous epidemiological, the HTLV-1 and 2 prevalence was 1·5% (CI 95%: 0·31-4·3) and 0·5% (CI 95%: 0·013-2·75), respectively. The strategy proposed herein has some advantages over other PCR-based tests because it not only reduces considerably time and the costs of the total diagnosis but also allows detection and discrimination of HTLV-1 and 2 in the same reaction.

Estimation of the window period of human T-cell leukemia virus type 1 and 2 tests by a lookback study of seroconverters among Japanese voluntary blood donors.

BACKGROUND: Japan is endemic for human T-cell leukemia virus type 1 (HTLV-1), and the horizontal transmission of HTLV-1 is often reported. However, the window period (WP) for serologic or molecular screening is unclear. STUDY DESIGN AND METHODS: Results for anti-HTLV-1 screening and confirmatory tests obtained from 648 591 repeated blood donors in the Kyushu district, one of the most endemic areas of HTLV-1 in the world, were evaluated. A lookback study was conducted for seroconverters. RESULTS: During 2012 to 2019, 436 seroconverters (155 men, 281women) were identified with use of a screening chemiluminescence enzyme-immunoassay (CLEIA) and multiple confirmatory tests. Because the period between the latest seronegative donation and seroconversion was highly variable (2.1-276.7 months), 19 cases that seroconverted within 6 months were subjected to the analysis. The WP of the particle agglutination assay and CLEIA was estimated to be 2.2 ± 0.6 and 2.6 ± 1.7 months, respectively. The WP of the indirect immunofluorescence assay was 4.8 ± 6.5 months. Although the WP of western blotting was estimated to be 6.3 ± 8.7 months, four cases were still indeterminate through the study period. Chemiluminescence and line immunoassays, the current screening and confirmatory tests used in the Japanese blood program, showed the shortest WP of 2.2 ± 0.6 months. The WP of real-time polymerase chain reaction for HTLV-1 was estimated to be 4.1 ± 7.8 months. CONCLUSIONS: The WP in commercially available testing systems for HTLV-1/2 was determined for natural infection among repeated blood donors. Considering the HTLV-1 WP will help increase transfusion safety and facilitate the accurate diagnosis of HTLV-1 infection.

HTLV screening of blood donors using chemiluminescence immunoassay in three major provincial blood centers of China.

BACKGROUND: Human T-cell lymphotropic virus (HTLV) remains a major safety concern for blood supplies. Despite many HTLV positive cases being reported in southeastern China, the detection of HTLV has not been prioritized in routine blood screening. Additionally, data on the prevalence of HTLV infection among blood donors is also limited. The objective of this study was to investigate the prevalence of HTLV among blood donors in three Chinese provinces through their representative blood centers, to evaluate the feasibility of chemiluminescence immunoassay (CLIA) for blood screening. METHODS: From November 2018 to March 2019, blood plasma samples were collected from Hebei, Changsha, and Shenzhen blood centers and were screened for the HTLV-1/2 antibody using a CLIA and enzyme-linked immunosorbent assay (ELISA). This was followed by confirmatory tests using INNO-LIA HTLV I/II. RESULTS: A total of 59,929 blood donations were collected and screened for HTLV-1/2. The reactive rate of CLIA and ELISA among donations in the Shenzhen blood center (0.0943%, 27/28,621) was higher than Hebei (0.0248%, 4/16,144), and Changsha (0.0198%, 3/15,164) (p < 0.05). After confirmation, 3 samples were confirmed as indeterminate for HTLV antibodies, and only one sample from the Shenzhen blood center was confirmed as HTLV-1. The overall prevalence of HTLV-1/2 was 1.67 per 100,000 (1/59,929). The HTLV-infected blood came from a 32-year-old first-time female donor with a high school degree, who belonged to the SHE ethnic minority and was born in the Fujian province. CONCLUSIONS: In summary, the overall prevalence of HTLV-1/2 among blood donors in the three blood centers in China remains relatively low. However, blood donations with positive or indeterminate results for HTLV antibodies reminded us of the importance of HTLV screening among blood donors in China.

Noninvasive Detection of Antibodies to Human T-Cell Lymphotropic Virus Types 1 and 2 by Use of Oral Fluid.

Human T-lymphotropic viruses type 1 and 2 (HTLV-1/2) are prevalent in endemic clusters globally, and HTLV-1 infects at least 5 to 10 million individuals. Infection can lead to inflammation in the spinal cord, resulting in HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP), or adult T cell leukemia/lymphoma (ATL). Obtaining venous blood for serological screening, typically performed using enzyme immunoassays (EIAs), is invasive, sometimes socially unacceptable, and has restricted large-scale seroprevalence studies. Collecting oral fluid (OF) is a noninvasive alternative to venesection. In this study, an IgG antibody capture EIA was developed and validated to detect anti-HTLV-1/2 IgG in OF. OF and plasma specimens were obtained from seropositive HTLV-1/2-infected patients attending the National Centre for Human Retrovirology (n = 131) and from HTLV-1/2-uninfected individuals (n = 64). The assay showed good reproducibility and high diagnostic sensitivity (100%) and specificity (100%) using both OF and plasma. The Murex HTLV I+II commercial assay was evaluated and did not detect anti-HTLV-1/2 IgG in 14% (5/36) of OF specimens from seropositive donors. The reactivities of OF and plasma in the IgG capture correlated strongly (r = 0.9290) and were not significantly affected by delayed extraction when held between 3°C and 45°C for up to 7 days to simulate field testing. The use of OF serological screening for HTLV-1/2 infection could facilitate large-scale seroprevalence studies, enabling active surveillance of infection on a population level.

Development and evaluation of human T-cell leukemia virus-1 and -2 multiplex quantitative PCR.

The diagnosis of human T -cell leukemia virus type 1 (HTLV-1) infection in Japan is usually performed by serological testing, but the high rate of indeterminate results from western blotting makes it difficult to assess the infection accurately. Nucleic acid tests for HTLV-1 and/or HTLV-2 are used to confirm infection with HTLV-1 and/or HTLV-2 and are also used for the follow-up of HTLV-1 related diseases. To prepare a highly sensitive method that can discern infection with HTLV-1 and HTLV-2, a multiplex quantitative polymerase chain reaction (qPCR) by large-scale primer screening was developed. Sensitivity and specificity were evaluated by serial dilution of cell lines and by testing with known clinical samples. The resulting multiplex qPCR can detect about four copies of HTLV-1 provirus per 105 cells. Moreover, HTLV-1 provirus could be detected in 97.2% (205 of 211) of HTLV-1 seropositive clinical samples. These sensitivities were sufficiently high compared with the methods reported previously. Also, all the HTLV-2 seropositive clinical samples tested were found to be positive by this method (three of three). In conclusion, this method can successfully and simultaneously detect both types of HTLV-1 and HTLV-2 provirus with extremely high sensitivity.

Confirmatory molecular method for HTLV-1/2 infection in high-risk pregnant women.

Human T-cell lymphotropic virus types 1/2 (HTLV-1/2) are transmitted through sexual intercourse, transfusion of blood components, and vertical transmission, predominantly through breastfeeding. Six hundred forty-three pregnant women from a high-risk prenatal care unit at a general hospital were tested by serological tests using chemiluminescence (CMIA) for screening, followed by a molecular confirmatory test. Four patients (0.6%) tested positive for HTLV-1/2 by CMIA, two samples (0.3%) for each patient were confirmed as having HTLV-1 or HTLV-2 by PCR. The results show the importance of inclusion of HTLV-1/2 screening for pregnant women in high-risk prenatal care and the need for a molecular biological method to confirm HTLV-1/2 infection.

Interpretation of low reactivity in the Abbott Architect rHTLV I/II assay.

OBJECTIVE: The objective of this study is to reduce donor tissue wastage. AIM: The aim of this study is to determine, in the case of the Abbott Architect rHTLV I/II assay, whether a signal/cut-off (S/CO) ratio higher than the manufacturer's recommendation of 1·0 could be applied to diagnose significant HTLV-1 seroreactivity. BACKGROUND: The detection of human T cell leukaemia virus type 1 (HTLV-1) infection is primarily based on serology often utilising random access platforms. Although current assays have high sensitivity and specificity, in low-prevalence regions, significant numbers of false-positive reactions occur. A comprehensive follow-up is difficult within the time frame of organ donation. This can lead to donor tissue wastage. METHODS: A retrospective analysis of 12 250 samples previously tested on the Abbott Architect rHTLV I/II platform and further tested by confirmatory serology/molecular detection to determine the sensitivity and positive predictive value in the S/CO ratio range was conducted. RESULTS: Where the sample S/CO ratio was >20 (n = 498), HTLV infection was confirmed in all but eight subjects. All of these eight had indeterminate confirmatory results, and none were found to be uninfected. Conversely, in the samples within the S/CO ratio range 1-4 (n = 271), no subject was subsequently found to be HTLV-infected although HTLV infection could not be excluded in all cases, primarily due to lack of follow-up samples (n = 60/271). CONCLUSIONS: Samples with an S/CO ratio of <4·0 on the Abbott Architect rHTLV I/II platform represent a low risk of HTLV infection in the UK, and organs from such donors might reasonably be considered for transplantation, within the context of appropriate risk-benefit assessment.

Making the invisible visible: searching for human T-cell lymphotropic virus types 1 and 2 (HTLV-1 and HTLV-2) in Brazilian patients with viral hepatitis B and C.

With this study, the authors hope to alert clinicians regarding the presence of human T-cell lymphotropic virus type 1 and 2 (HTLV-1/-2) infections in patients with viral hepatitis B and C in Brazil. HTLV-1/-2 were detected in 1.3% of hepatitis B virus (HBV)- and 5.3% of hepatitis C virus (HCV)-infected blood samples sent for laboratory viral load measurements. A partial association of human immunodeficiency virus (HIV)-1 and HTLV-1/-2 infection was detected in patients with HCV (HIV+, 27.3%), whereas this association was almost 100% in HBV-infected patients (HIV+, all except one). The high prevalence of HTLV-1/-2 infection among patients with hepatitis C was of concern, as HTLV-1/-2 could change the natural course of subsequent liver disease. The authors suggest including HTLV-1/-2 serology in the battery of tests used when following patients with viral hepatitis in Brazil, regardless of the HIV status.

Evaluation of Sensitivity and Specificity Performance of Elecsys HTLV-I/II Assay in a Multicenter Study in Europe and Japan.

Screening of blood for human T-cell lymphotropic virus type 1 and type 2 (HTLV-1 and -2, respectively) is important to diagnose and prevent infection and ensure the safety of blood supplies. The Elecsys HTLV-I/II assay is a newly developed, electrochemiluminescence screening assay for the detection of HTLV-1/2 infection. The sensitivity and specificity of the Elecsys HTLV-I/II assay were determined using well-characterized HTLV-1/2-positive serum and plasma samples and routine diagnostic and blood donor samples expected to be HTLV negative, respectively. These results were compared with those for at least one of the following CE-marked assays at seven independent laboratories and the Roche Diagnostics facility in Penzberg, Germany: Abbott Architect rHTLV-I/II, Ortho Avioq HTLV-I/II Microelisa system, Abbott Prism HTLV-I/HTLV-II, and DiaSorin Murex HTLV I+II. Fujirebio INNO-LIA HTLV-I/II Score was used as a confirmatory assay. The Elecsys HTLV-I/II, Abbott Architect rHTLV-I/II, and Abbott Prism HTLV-I/HTLV-II assays detected all HTLV-1/2-positive samples (sensitivity, 100%). Sensitivity for Ortho Avioq HTLV-I/II was 98.63%. The Elecsys HTLV-I/II assay had a specificity of 99.95% in blood donor samples, which was comparable to results for the other assays (range, 99.91 to 100%). In routine diagnostic samples, the specificity of the Elecsys HTLV-I/II assay was 99.83%, compared with 99.70% for Abbott Architect rHTLV-I/II. Specificity for the Elecsys HTLV-I/II assay in potentially cross-reactive samples was 100%, compared with 99.0% for Ortho Avioq HTLV-I/II and 99.2% for DiaSorin Murex HTLV I+II. The Elecsys HTLV-I/II assay has the sensitivity and specificity to support its use as a routine screening assay for detecting HTLV infection.

Human T-lymphotropic virus and transfusion safety: does one size fit all?

Human T-cell leukemia viruses (HTLV-1 and HTLV-2) are associated with a variety of human diseases, including some severe ones. Transfusion transmission of HTLV through cellular blood components is undeniable. HTLV screening of blood donations became mandatory in different countries to improve the safety of blood supplies. In Japan and Europe, most HTLV-infected donors are HTLV-1 positive, whereas in the United States a higher prevalence of HTLV-2 is reported. Many industrialized countries have also introduced universal leukoreduction of blood components, and pathogen inactivation technologies might be another effective preventive strategy, especially if and when generalized to all blood cellular products. Considering all measures available to minimize HTLV blood transmission, the question is what would be the most suitable and cost-effective strategy to ensure a high level of blood safety regarding these viruses, considering that there is no solution that can be deemed optimal for all countries.

Evaluation of the New Multi-HTLV Serological Assay: Improvement for HTLV-2 Detection.

Despite the accuracy of confirmatory tests for the diagnosis of human T cell lymphotropic virus (HTLV), inconclusive or false-negative results still occur when diagnosing human T cell lymphotropic virus type 2 (HTLV-2)-positive patients. The goal of this study was to evaluate the sensitivity and accuracy of a confirmatory immunoassay, the Multi-HTLV assay. A total of 246 plasma samples were tested by real-time polymerase chain reaction (qPCR) and used to calculate the sensitivity and typing accuracy of the Multi-HTLV assay. Of the 246 plasma samples, 127 were positive for human T cell lymphotropic virus type 1 (HTLV-1), 112 were positive for HTLV-2, and 7 were positive for both HTLV-1 and HTLV-2. Thereafter, the nonparametric Mann-Whitney U test was used to calculate the concordance between the qPCR test and Multi-HTLV assay in 12 samples with discrepant and inconclusive qPCR results. The Multi-HTLV assay showed high performance in identifying HTLV-1 and HTLV-2 with sensitivities of 97% [95% confidence interval (CI): 0.92-0.98] and 94% (0.87-0.96), respectively. However, due to typing performance (98% for HTLV-1 and 94% for HTLV-2), it had 95% agreement with positive HTLV-1 qPCR results (95% CI: 90.07-97.81) and 86% (78.04-91.01) of HTLV-2 qPCR results were positive. Moreover, this test was able to recognize 80% of indeterminate samples and all HTLV-2 positive samples that showed false-negative qPCR results. Our findings, derived from a substantial number of HTLV-positive samples, underscore the inherent reliability and feasibility of the Multi-HTLV assay, regardless of the molecular testing facilities. Furthermore, the distinctive multiparametric nature of this assay, combined with its straightforward procedural execution, introduces novel perspectives for analyzing specific serological profiles in each patient, as well as the potential for immunological monitoring of disease progression.

Performance of immunological assays for universal and differential diagnosis of HTLV-1/2 infection in candidates for blood donations from the Brazilian Amazon.

The present study compares the ability of distinct immunological assays (chemiluminescence immunoassay-CLIA, western blot-WB and flow cytometry-FC-Simplex and Duplex) to detect anti-HTLV (human T-lymphotropic virus) antibodies in candidates for blood donations at the Amazonas State Blood Center (Brazil) between January 2018 and December 2022. Overall, 257,942 samples from candidates for blood donations were screened using CLIA, which led to 0.15% seropositivity for HTLV (409 samples). A total of 151 candidates for blood donations were enrolled for retesting with CLIA followed by additional testing using WB and FC-Simplex and Duplex analysis. Our results demonstrated that 62% (93/151), 20% (30/151) and 17% (26/151) of the samples presented positive results with retesting using CLIA, WB and FC-Simplex analysis, respectively. Additional analysis of the CLIA, WB and FC-Simplex results revealed an overall agreement of 56% for CLIA and WB (22 co-negative; 30 co-positive samples), 48% for CLIA and FC-Simplex (21 co-negative; 24 co-positive samples) and 80% for WB and FC-Simplex (51 co-negative; 23 co-positive samples). Considering the WB as the reference standard for the diagnosis of infection with HTLV-1/2, we observed that the CLIA results of ≤3.0 RLU and >10.0 RLU in the retest can be used define a negative or positive result, respectively, and could be used as new specific cut-off values. The overall agreement between WB and FC-Duplex for accomplishing the differential diagnosis was evaluated and demonstrated 100% correspondence for the diagnosis of HTLV-1 (15/15) and HTLV-2 (7/7). Our findings demonstrate that gaps in the diagnosis of infection with HTLV-1/2 could be overcome by the simultaneous use of distinct immunological assays during retesting of candidates for blood donations.

[Serological diagnosis of HTLV-1/2: combination of screening assays to define the serological status in blood donors]. / Diagnóstico serológico de HTLV-1/2: combinación de técnicas de tamizaje para definir el estatus serológico en donantes de sangre.

Alternative algorithms were evaluated in order to reduce the number of false reactive results for antibodies against HTLV-1/2. From 20,210 samples tested, 0.37% (74/20,210) was reactive by ELISA Murex. Of these, 23 were confirmed as positive by the indirect immunofluorescence assay whereas 51 were negative, being the positive predictive value (PPV) 31.08%. From a combination of the ELISA Murex assay with the particle agglutination assay (PA) and ELISA MP, the following results were obtained: 26/74 were reactive by ELISA Murex and PA, PPV 88.5% and 32/74 were reactive by ELISA Murex and ELISA MP, PPV 71.8 %. The ROC curve analysis determined that for an RP 4.74, the values for sensitivity, specificity, PPV and NPV by ELISA Murex were 100%, 98.04%, 95.8% and 100%, respectively. We propose that reactive samples by ELISA Murex with an RP d 4.74 should be retested in duplicate by PA, and the resulting concordantly nonreactive samples should be defined as negative for HTLV-1/2.

HTLV-1/2 Infection in Blood Donors from a Non-Endemic Area (Catalonia, Spain) between 2008 and 2017: A 10-Year Experience.

Human T-cell lymphotropic virus type 1 and 2 (HTLV-1/2) screening is not mandatory in Spanish blood banks. In Catalonia, selective screening was introduced in 2008, followed by universal screening in 2011. We present herein a 10-year experience of HTLV testing in blood donors. HTLV-1/2 selective screening was performed using Ortho-Clinical Diagnostics HTLV-I/HTLV-II Ab-Capture ELISA between February 2008 and May 2009, then Abbott Prism HTLV-I/ HTLV-II assay until December 2010. Abbott Architect rHTLV-I/II assay was then used for HTLV-1/2 universal screening in pooled samples. INNO-LIA HTLV I/II Score (Fujirebio) and in-house HTLV-1/2 proviral DNA real-time PCR were used in reactive samples. Follow-up was offered to confirm HTLV-1/2 donors in Vall d'Hebron Hospital. Between 2008 and 2017, 51 blood donors were confirmed HTLV positive (46 HTLV-1, 4 HTLV-2 and 1 HTLV) out of 2,114,891 blood donations (1 in 41,468). Sixty-nine percent were female, median age was 40 years and most were born in Latin America (69%), followed by Europe (25%), Africa (4%) and Asia (2%). Screening of relatives and partners identified 12 additional HTLV-1 cases. Lookback studies did not show any HTLV-1/2 transmission. HTLV infections found in blood donors mirror epidemiological changes in the population of Spain. Consequently, HTLV should be considered a potential risk for recipients and calls for the design of optimal strategies to ensure transfusion safety.

The Relevance of a Diagnostic and Counseling Service for People Living With HTLV-1/2 in a Metropolis of the Brazilian Amazon.

Introduction: To identify the prevalence of infection in the urban area of the capital city of Belém, Brazil, the Laboratory of Virology of the Federal University of Pará implemented, as a public service, serological screening for human T-lymphotropic viruses 1 and 2 (HTLV-1/2) infection and, if necessary, counseling service and referral to specialized medical care. The project is funded by the National Council of Science and Technology, the Ministry of Health of Brazil and the Pan American Health Organization. Methods: From January 2020 to June 2021, 1,572 individuals of both sexes were approached to answer a questionnaire and were tested using an enzyme immunoassay (Murex HTLV-I+II, DiaSorin, Dartford, UK). Seropositive samples were confirmed as HTLV-1 and HTLV-2 infection by line immunoassay (INNO-LIA® HTLV I/II Score, Fujirebio, Japan) and/or by real-time polymerase chain reaction. G and Fisher's exact tests were applied to identify the association between epidemiological characteristics and HTLV-1/2 infection. Results: Of the 1,572 screened individuals, 63.74% were females between the ages of 30 and 59 years (49.04%). Infection was confirmed in six individuals (0.38%), among whom three (0.19%) were infected with HTLV-1 and three with HTLV-2 (0.19%). Blood transfusion before 1993 was the main risk factor associated with the route of exposure to the virus (p = 0.0442). The infected individuals were referred to a counseling session with a nursing professional, and two patients who manifested signs and symptoms suggestive of myelopathy associated with HTLV were referred to a neurologist. Conclusion: The implementation of the screening service revealed the occurrence of moderate endemicity of HTLV-1/2 in Belém, reinforcing the importance of continuing the service as a means of establishing an early diagnosis and providing counseling as a measure to prevent and control viral transmission in the general population.

Prevalence and Risk Factors for HTLV-1/2 Infection inRiverside and Rural Populations of the State of Pará.

Human T-lymphotropic viruses 1 and 2 (HTLV-1 and HTLV-2) infection has been described in several Amazonian populations; however, there is still a lack of data on the prevalence of the virus in riparian populations living in rural areas of the state of Pará. The present study aimed to evaluate the prevalence of HTLV-1/2 infection in four riverine communities and one rural area in the state of Pará and to describe the possible risk factors for infection. A total of 907 individuals responded to an epidemiological survey and gave blood samples collected for anti-HTLV-1/2 antibodies by immunoenzymatic assay (EIA). The serum-reactive samples were subjected to confirmation by an in-line assay (Inno-Lia) and by proviral DNA screening using real-time PCR (qPCR). The total prevalence was 0.8% (7/907) for HTLV-1/2 (CI: 0.2-1.3%), with 0.66% HTLV-1 and 0.11% HTLV-2. The prevalence by sex was 0.7% in women (4/565) and 0.9% in men (3/342). Among seropositive patients, 83.3% (5/7) reported being sexually active, and 57.1% (4/7) reported not having the habit of using condoms during their sexual relations. Intrafamily infection was also observed. The results reinforce the need for public policies to prevent and block the spread of HTLV, especially in riparian communities that are subject to difficulties in accessing the Unified Health System (Sistema Único de Saúde/SUS) because infected individuals need clinical monitoring for surveillance and early diagnosis of symptoms associated with HTLV-1.