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.

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.

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.

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.

Multi-Epitope Protein as a Tool of Serological Diagnostic Development for HTLV-1 and HTLV-2 Infections.

A multi-epitope protein expressed in a prokaryotic system, including epitopes of Env, Gag, and Tax proteins of both HTLV-1 and HTLV-2 was characterized for HTLV-1/2 serological screening. This tool can contribute to support the implementation of public policies to reduce HTLV-1/2 transmission in Brazil, the country with the highest absolute numbers of HTLV-1/2 infected individuals. The chimeric protein was tested in EIA using serum/plasma of HTLV-infected individuals and non-infected ones from four Brazilian states, including the North and Northeast regions (that present high prevalence of HTLV-1/2) and Southeast region (that presents intermediate prevalence rates) depicting different epidemiological context of HTLV-1/2 infection in our country. We enrolled samples from Pará (n = 114), Maranhão (n = 153), Minas Gerais (n = 225) and São Paulo (n = 59) states; they are from blood donors' candidates (Pará and Minas Gerais), pregnant women (Maranhão) and HIV+/high risk for sexually transmitted infection (STI; São Paulo). Among the HTLV-1/2 positive sera, there were co-infections with viral (HTLV-1 + HTLV-2, HIV, HCV, and HBV), bacterial (Treponema pallidum) and parasitic (Trypanosoma cruzi, Schistosma mansoni, Strongyloides stercoralis, Entamoeba coli, E. histolytica, and Endolimax nana) pathogens related to HTLV-1/2 co-morbidities that can contribute to inconclusive diagnostic results. Sera positive for HIV were included among the HTLV-1/2 negative samples. Considering both HTLV-1 and HTLV-2-infected samples from all states and different groups (blood donor candidates, pregnant women, and individuals with high risk for STI), mono or co-infected and HTLV-/HIV+, the test specificity ranged from 90.09 to 95.19% and the sensitivity from 82.41 to 92.36% with high accuracy (ROC AUC = 0.9552). This multi-epitope protein showed great potential to be used in serological screening of HTLV-1 and HTLV-2 in different platforms, even taking into account the great regional variation and different profile of HTLV-1 and HTLV-2 mono or co-infected individuals.

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.

Prevalence and Risk Factors for HTLV-1/2 Infection in Quilombo Remnant Communities Living in the Brazilian Amazon.

Human T-lymphotropic viruses 1 and 2 (HTLV-1 and HTLV-2) are retroviruses that originated on the African continent and dispersed throughout other continents through human migratory flows. This study describes the prevalence of HTLV-1 and HTLV-2 infection in residents of 11 quilombo remnant communities in the state of Pará, Brazil, and the associated risk factors. A total of 859 individuals (334 men and 525 women), aged between 7 and 91 years, participated in the study. All subjects answered a questionnaire with questions on sociodemographic characteristics and on risk factors associated with HTLV infection, and blood samples were collected and separated into plasma and leukocytes. An immunoenzymatic assay (ELISA; Murex HTLV-I+II, DiaSorin, Dartford, UK) was used as a screening test, and positive samples were subjected to line immunoassay confirmatory tests (Inno-LIA HTLV I/II Score FUJIREBIO) and DNA extraction for subsequent real-time PCR to differentiate the viral type. Four of the 859 individuals were seropositive for HTLV. HTLV-1 infection was confirmed in one individual from the Itamoari community (0.92%), and HTLV-2 infection was confirmed in two individuals from São Benedito (3.17%) and in one individual from Arimandeua (2.22%). Blood transfusion was the only risk factor associated with HTLV infection in this study. This study reports the occurrence of HTLV-1 and HTLV-2 in quilombo remnant communities in the state of Pará. Considering the African origin of the virus and its introduction into Brazil from the slave trade, the continued evaluation of quilombola communities in the state of Pará is essential to better characterize the distribution of infections in these populations and to create public health policies for the control of the spread of the virus and associated diseases.

Clinical and Laboratory Outcomes in HIV-1 and HTLV-1/2 Coinfection: A Systematic Review.

Aim: To perform a systematic review to describe the available findings on clinical outcomes in HIV-1 and HTLV-1/HTLV-2 co-infected individuals since 1995. Design: This Systematic Review used PECO criteria follow by PRISMA reporting guidelines and registered as CRD42021279062 (Prospero database). The Newcastle-Ottawa Scale assessed the methodological quality of included studies. Data Collection and Analysis: A systematical search in PubMed/MEDLINE, Embase, Web of Sciences databases for cross-sectional, case-control, or cohort studies design to identify clinical and laboratorial outcomes related to HIV-1 and HTLV-1/2 coinfection. Search strategy: [("HIV-1" AND "HTLV-1" OR "HTLV-2") AND ("Coinfection") AND (1990/01/01:2021/12/31[Date- Publication])]. Results: A total of 15 articles were included on this systematic review describing data of 2,566 mono and coinfected patients, 58% male, with mean age was 35.7 ± 5.7 years. HIV-1 and HTLV-1 coinfected patients were more likely to had shorter survival and faster progression to death or mortality than monoinfected ones. Coinfected had higher CD4 cell counts and less likelihood of ART use. In addition, higher frequency of diseases like ichthyosis (22.2 vs. 6.8%), scabies (18.6 vs. 0%), candidiasis (42 vs. 12%), Strongyloidiasis (15.4 vs. 2%) and neurological manifestations like encephalopathy, peripheral neuropathy and HAM/TSP were more frequently reported in coinfected patients. Conclusions: HIV-1 and HTLV-1 coinfection and HIV-1 and HTLV-1 /2 triple coinfection were related to shorter survival, higher mortality rate, and faster progression to death, while coinfection by HIV-1/HTLV-2 seems to have neutral association with longer survival, slower AIDS progression, and lower mortality rate. The available evidence indicates an urgent need for prevention and control measures, including screening, diagnosis, and treatment of HIV-1 and HTLV-1/2 coinfected patients. Test-and-treat strategy for patients living with HIV in areas endemic for HTLV infection is mandatory, to avoid the risks of delayed therapy and death for coinfected patients. Systematic Review Registration: https://www.crd.york.ac.uk/prospero/, identifier: CRD42021279062.

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.

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.

HTLV-1 and HTLV-2 Infection Among Warao Indigenous Refugees in the Brazilian Amazon: Challenges for Public Health in Times of Increasing Migration.

INTRODUCTION: Human T-lymphotropic virus (HTLV) infection is endemic in indigenous populations of the Americas. We describe herein the prevalence of HTLV-1 and HTLV-2 infection among Warao indigenous refugees from Venezuela living in Belém, Pará, Brazil. METHODS: In total, 101 individuals of both sexes (43 men and 58 women) between 18 and 77 years of age were investigated. Blood samples were collected and separated into plasma and leukocytes. Serological screening was performed using an enzyme-linked immunosorbent assay (ELISA; Murex HTLV-I+II, DiaSorin, Dartford, UK), and seropositive samples were submitted to proviral DNA extraction followed by real-time polymerase chain reaction (qPCR). A nested PCR of the env region (630 bp) followed by enzymatic digestion with XhoI was performed to identify the molecular subtype of HTLV-2, in addition to sequencing analysis of the 5'LTR-I and 5'-LTR-II regions. RESULTS: Of the 101 individuals analyzed, 3 (3.0%) were seropositive. Molecular analysis of the pol and tax genes confirmed the HTLV-1 infection in a 55-year-old woman and HTLV-2 infection in a man (68 years old) and a woman (23 years old). HTLV-2 strains were defined by enzymatic digestion as belonging to the HTLV-2b subtype. The sequencing of the 5'LTR regions confirmed the presence of subtype 2b and identified HTLV-1 as belonging to subtype 1A (Cosmopolitan) and the Transcontinental subgroup. Among the infected patients, it was possible to conduct medical interviews with two individuals after delivery of the result. One patient with HTLV-2 reported symptoms such as joint pain, foot swelling, frequent headache, dizziness and lower back pain. The HTLV-1-positive woman was diagnosed with a tumor, dementia, urinary incontinence, felt body pain, and had spots on her body. The presence of the HTLV-2b subtype highlights the prevalence of this molecular variant among indigenous South Americans, as well as the presence of HTLV-1 Transcontinental, which has a worldwide distribution. CONCLUSION: These results reveal a high prevalence of HTLV-1/2 infection among Warao immigrants, suggesting migratory flow as a virus spread mechanism among human populations and alert public authorities to the need to create epidemiological surveillance programs, public social and health policies aimed at welcoming immigrants in the Brazilian territory.

Prevalence of infection by human T Cell lymphotropic viruses (HTLV-1/2) in adult population in Vitória-ES.

INTRODUCTION: Brazil has a high number of HTLV-1/2 infections which are unequally distributed in the country. Most prevalence studies have focused on specific populations, such as blood donors and pregnant women. Some areas, for example the state of Bahia, have robust information about HTLV-1/2 infection, however there is no information available about this infection in the general population of Vitória, Espírito Santo, Brazil. OBJECTIVE: To determine the prevalence of HTLV-1/2 infection in adults from the municipality of Vitoria, ES. METHODS: A cross sectional study was performed from September 2010 to December 2011, in individuals of both sexes, aged 18 or older living in Vitória-ES. Venous blood samples were collected and tested for anti-HTLV-1/2 antibodies by chemiluminescent immunoassay (CMIA). Individuals with CMIA reactive results were submitted to a new blood collection for retesting by CMIA, followed by PCR to confirm infection and discriminate the viral type. RESULTS: From 1502 tested samples, eight were reactive in CMIA and all were confirmed by PCR. Therefore, the prevalence of HTLV-1/2 was 0.53% (8/1502, 95% CI: 0.2-1.0%). The infection rate was 0.7% in men (5/711, 95% CI: 0.17-1.51%), and 0.38% in women (3/791, 95% CI: 0-0.81%). CONCLUSIONS: The prevalence of HTLV-1/2 infection was 0.53% (8/1502; 95% CI: 0.2-0.9%). Confirmatory test using real-time PCR (qPCR) identified seven individuals positive for HTLV-1 and one for HTLV-2. Considering the risk of infected individuals to develop high morbidity and mortality diseases, it would be important to implement public health policies aimed at stopping transmission of these viruses in this municipality.

Laboratory diagnosis of human T-lymphotropic virus in Brazil: assays, flowcharts, challenges, and perspectives.

INTRODUCTION: We present a data analysis and review of recent studies regarding the laboratory diagnosis of human T-lymphotropic virus 1 and 2 (HTLV-1/2) infections in Brazil. METHODS: Target populations, available diagnostic serological assays (screening and complementary tests), molecular assays (in-house), causes of false-positive and false-negative results, and flowcharts were analyzed. RESULTS: A table presents the target populations, two diagnostic flowcharts (depending on laboratory infrastructure and study population), and recent research that may improve how HTLV-1/2 is diagnosed in Brazil. CONCLUSIONS: Our results support the implementation of public policies to reduce HTLV-1/2 transmission and its associated diseases.

Specificity of HTLV screening tests and its impact on health care program costs: The perspective of antenatal screening in Brazil.

INTRODUCTION: Brazil ranks first in the number of HTLV-1/-2-infected individuals worldwide. The high morbidity and mortality of HTLV-1-associated diseases, especially following infection in infancy, requires strong action to reduce vertical transmission. METHODS: To facilitate the appraisal of the implementation of the HTLV antenatal screening program by the Brazilian Ministry of Health, we determined the costs in distinct scenarios according to HTLV seroprevalence, specificity of the screening test, and type of confirmatory test. RESULTS: HTLV antenatal screening would cost R$ 55,777,012-R$ 77,082,123/year. Screening assays with high specificity reduce the need and cost of confirmatory assays by up to 25%. CONCLUSIONS: Careful selection of the screening assay is required to optimize the program.

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.

Prevalence of infection by human T Cell lymphotropic viruses (HTLV-1/2) in adult population in Vitoria-ES

ABSTRACT Introduction: Brazil has a high number of HTLV-1/2 infections which are unequally distributed in the country. Most prevalence studies have focused on specific populations, such as blood donors and pregnant women. Some areas, for example the state of Bahia, have robust information about HTLV-1/2 infection, however there is no information available about this infection in the general population of Vitoria, Espírito Santo, Brazil. Objective: To determine the prevalence of HTLV-1/2 infection in adults from the municipality of Vitoria, ES. Methods: A cross sectional study was performed from September 2010 to December 2011, in individuals of both sexes, aged 18 or older living in Vitoria-ES. Venous blood samples were collected and tested for anti-HTLV-1/2 antibodies by chemiluminescent immunoassay (CMIA). Individuals with CMIA reactive results were submitted to a new blood collection for retesting by CMIA, followed by PCR to confirm infection and discriminate the viral type. Results: From 1502 tested samples, eight were reactive in CMIA and all were confirmed by PCR. Therefore, the prevalence of HTLV-1/2 was 0.53% (8/1502, 95% CI: 0.2-1.0%). The infection rate was 0.7% in men (5/711, 95% CI: 0.17-1.51%), and 0.38% in women (3/791, 95% CI: 0 -0.81%). Conclusions: The prevalence of HTLV-1/2 infection was 0.53% (8/1502; 95% CI: 0.2 -0.9%). Confirmatory test using real-time PCR (qPCR) identified seven individuals positive for HTLV-1 and one for HTLV-2. Considering the risk of infected individuals to develop high morbidity and mortality diseases, it would be important to implement public health policies aimed at stopping transmission of these viruses in this municipality. 2021 Sociedade Brasileira de Infectologia. Published by Elsevier España, S.L.U. This is an open access article under the CC BY-NC-ND license

Laboratory diagnosis of human T-lymphotropic virus in Brazil: assays, flowcharts, challenges, and perspectives

Abstract INTRODUCTION We present a data analysis and review of recent studies regarding the laboratory diagnosis of human T-lymphotropic virus 1 and 2 (HTLV-1/2) infections in Brazil. METHODS Target populations, available diagnostic serological assays (screening and complementary tests), molecular assays (in-house), causes of false-positive and false-negative results, and flowcharts were analyzed. RESULTS A table presents the target populations, two diagnostic flowcharts (depending on laboratory infrastructure and study population), and recent research that may improve how HTLV-1/2 is diagnosed in Brazil. CONCLUSIONS: Our results support the implementation of public policies to reduce HTLV-1/2 transmission and its associated diseases.

HTLV-2 infection in Manaus, Brazil: first description of HTLV-2c subtype in an urban area of the Western Amazon region

Abstract INTRODUCTION: We investigated the prevalence of human T-cell lymphotropic virus types 1 and 2 (HTLV-1/2) infection in patients with hematological diseases from the western Amazon region of Brazil. METHODS: Samples from 306 patients were submitted for the molecular diagnosis of HTLV-1/2 infection by real time PCR (qPCR), with amplification, sequencing, and phylogenetic analysis of the long terminal repeat (LTR) region. RESULTS: A 29-year-old male carrier of sickle cell anemia with a history of multiple blood transfusions was diagnosed with the HTLV-2c subtype. CONCLUSIONS: This study describes the first known occurrence of HTLV-2c in the urban area of Brazil's western Amazon region.