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.

Human T-Lymphotropic Virus type-1 (HTLV-1) is a unique retrovirus associated with both leukemogenesis and a specific neuroinflammatory condition known as HTLV-1-Associated Myelopathy (HAM). Currently, most proposed HAM biomarkers require invasive CSF sampling, which is not suitable for large cohorts or repeated prospective screening. To identify non-invasive biomarkers for incident HAM in a large Brazilian cohort of PLwHTLV-1 (n=615 with 6,673 person-years of clinical follow-up), we selected all plasma samples available at the time of entry in the cohort (between 1997-2019), in which up to 43 cytokines/chemokines and immune mediators were measured. Thus, we selected 110 People Living with HTLV-1 (PLwHTLV-1), of which 68 were neurologically asymptomatic (AS) at baseline and 42 HAM patients. Nine incident HAM cases were identified among 68 AS during follow-up. Using multivariate logistic regression, we found that lower IL-10, IL-4 and female sex were independent predictors of clinical progression to definite HAM (AUROC 0.91), and outperformed previously suggested biomarkers age, sex and proviral load (AUROC 0.77). Moreover, baseline IL-10 significantly predicted proviral load dynamics at follow-up in all PLwHTLV-1. In an exploratory analysis, we identified additional plasma biomarkers which were able to discriminate iHAM from either AS (IL6Rα, IL-27) or HAM (IL-29/IFN-λ1, Osteopontin, and TNFR2). In conclusion, female sex and low anti-inflammatory IL-10 and IL-4 are independent risk factors for incident HAM in PLwHTLV-1,while proviral load is not, in agreement with IL-10 being upstream of proviral load dynamics. Additional candidate biomarkers IL-29/IL-6R/TNFR2 represent plausible therapeutic targets for future clinical trials in HAM patients.

BACKGROUND: Human T-cell lymphotropic virus type 1 (HTLV-1), also denominated Human T-cell leukemia virus-1, induces immune activation and secretion of proinflammatory cytokines, especially in individuals with HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). Regulatory T lymphocytes (Tregs) may control of inflammation through the production of regulatory cytokines, including IL10 and TGF-β. In this study we determined the frequencies of CD4 + and CD8 + Tregs in a HAM/TSP population, compared to asymptomatic carriers and uninfected individuals, as well as investigated the profiles of regulatory and inflammatory cytokines.
METHODS: Asymptomatic HTLV-1 carriers and HAM/TSP patients were matched by sex and age. The frequencies of IL10- and/or TGF-β-producing Tregs were quantified by flow cytometry. Real-time reverse transcription polymerase chain reaction (RT-PCR) was used to quantify HTLV-1 proviral load and the mRNA expression of cytokines and cellular receptors in peripheral blood mononuclear cells.
RESULTS: Total frequencies of CD4 + Tregs, as well as the IL10-producing CD4 + and CD8 + Treg subsets, were statistically higher in patients with HAM/TSP compared to asymptomatic HTLV-1-infected individuals. In addition, a positive correlation was found between the frequency of CD4 + IL10 + Tregs and proviral load in the HAM/TSP patients evaluated. A positive correlation was also observed between gene expression of proinflammatory versus regulatory cytokines only in HAM / TSP group.
CONCLUSIONS: A higher frequencies of IL10-producing Tregs were identified in patients with HAM/TSP. Imbalanced production of IL10 in relation to TGF-β may contribute to the increased inflammatory response characteristically seen in HAM/TSP patients.

Human T-lymphotropic virus type-1 (HTLV-1) was the first discovered human oncogenic retrovirus, the etiological agent of two serious diseases have been identified as adult T-cell leukaemia/lymphoma malignancy and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP), a debilitating chronic neuro-myelopathy. Despite more than 40 years of molecular, histopathological and immunological studies on HTLV-1-associated diseases, the virulence and pathogenicity of this virus are yet to be clarified. The reason why the majority of HTLV-1-infected individuals (∼95%) remain asymptomatic carriers is still unclear. The deterioration of the immune system towards oncogenicity and autoimmunity makes HTLV-1 a natural probe for the study of malignancy and neuro-inflammatory diseases. Additionally, its slow worldwide spreading has prompted public health authorities and researchers, as urged by the WHO, to focus on eradicating HTLV-1. In contrast, neither an effective therapy nor a protective vaccine has been introduced. This comprehensive review focused on the most relevant studies of the neuro-inflammatory propensity of HTLV-1-induced HAM/TSP. Such an emphasis on the virus-host interactions in the HAM/TSP pathogenesis will be critically discussed epigenetically. The findings may shed light on future research venues in designing and developing proper HTLV-1 therapeutics.

Background and Objectives: Adult T-cell leukemia/lymphoma (ATLL) is a highly aggressive T-cell lymphoproliferative disease associated with the human T-cell lymphotropic virus type I (HTLV-1). ATLL is a rare disease, found more frequently in HTLV-1-endemic areas, Romania being one of them. Despite treatment advances, the prognosis remains dismal. We aimed to describe the clinical, biological, and survival outcome features of Romanian patients with aggressive-type ATLL. Materials and Methods: We report the data of a prospective, observational, and unicentric study of all 20 patients diagnosed with lymphoma and acute types of ATLL at our center over the past 12 years. Data were collected from the patients\' medical records. Results: Lymphoma-type ATLL (60%) was more common than acute-type ATLL (40%). Median age at diagnosis was 40.5 years, and most patients were female. Laboratory data revealed significant differences between acute and lymphoma-type ATLL, namely, higher leukocyte (p = 0.02) and lymphocyte counts (p = 0.02) and higher levels of corrected calcium (p = 0.001) in acute-type ATLL. All patients received chemotherapy, and only two underwent allogeneic stem cell transplantation. Only six patients obtained a complete or partial response to chemotherapy, mostly the lymphoma-type ones. The median survival for all patients was 6.37 months, with higher survival in the lymphoma-type ATLL (8.16 months) than in the acute-type (3.60 months). Normal calcium levels (p = 0.011), uric acid (p = 0.005), BUN score (p = 0.000), JCOG-PI moderate risk (p = 0.038), and obtaining complete or partial response (p = 0.037) were associated with higher survival. Conclusion: Aggressive-type ATLL among Romanian patients presents distinct characteristics, including younger age at diagnosis, female predominance, and higher incidence of lymphoma-type ATLL compared to currently reported data. Survival remains very low, with all subtypes experiencing a median survival of less than one year.

Human T-cell leukemia virus type 1 (HTLV-1) infection is linked to the development of adult T-cell leukemia/lymphoma (ATLL) and the neuroinflammatory disease, HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). The HTLV-1 Tax oncoprotein regulates viral gene expression and persistently activates NF-κB to maintain the viability of HTLV-1-infected T cells. Here, we utilize a kinome-wide shRNA screen to identify the tyrosine kinase KDR as an essential survival factor of HTLV-1-transformed cells. Inhibition of KDR specifically induces apoptosis of Tax expressing HTLV-1-transformed cell lines and CD4 + T cells from HAM/TSP patients. Furthermore, inhibition of KDR triggers the autophagic degradation of Tax resulting in impaired NF-κB activation and diminished viral transmission in co-culture assays. Tax induces the expression of KDR, forms a complex with KDR, and is phosphorylated by KDR. These findings suggest that Tax stability is dependent on KDR activity which could be exploited as a strategy to target Tax in HTLV-1-associated diseases.

暂无摘要。

OBJECTIVE: The HTLV-1 infection persists for life, remaining as asymptomatic viral reservoirs in most patients, ensuring the chain of transmission, but around 4% develop adult T-cell leukemia/lymphoma (ATLL). HTLV-1 is an oncogenic retrovirus that transforms CD4+ T lymphocytes and deregulates the lymphoproliferative pathways that contribute to the development of ATLL. To achieve cell transformation, most oncogenic retroviruses use proto-oncogene capture transduction, with proviral integration disrupting the expression of tumor suppressors or proto-oncogenes.
OBJECTIVE: We conducted this study on the prevalence of HTLV-1 infection in blood donors to expand the HTLV-1 database, assess the risk of transmission via blood products, as well as evaluate the risk of persistent infection or development of neoplastic diseases in HTLV-1 carriers.
METHODS: This is a cross-sectional study of blood donors of all categories. For this study, 265 blood donors were recruited at the Centre National de Transfusion Sanguine in Brazzaville. After testing for HTLV-1 antibodies by ELISA, proviral DNA was extracted from all ELISA-positive samples for detection by nested PCR, followed by RT qPCR using specific primers p53 and c-myc for gene expression.
RESULTS: 20/265 were positive for anti-HTLV-1 antibody, 5 donors were positive for proviral DNA. The prevalence of HTLV-1 was 1.8%. All HTLV-1-positive donors were male (1.8%), with a positive correlation (p = 0.05); the 1.1% of positive donors were regular, with the majority aged between 31 and 45 years (1.5%), and concubine donors were the most frequent (1.1%). All samples showed normal expression of the p53 and c-myc genes.
CONCLUSIONS: The prevalence, though low, remains a serious problem. No abnormal p53 or c-myc gene expression was detected in HTLV-1-positive donors, which could mean that none of the T lymphocytes in these donors had been transformed by HTLV-1.
Введение. Инфекция HTLV-1 сохраняется в течение всей жизни человека, обусловливая бессимптомное вирусное носительство у большинства пациентов и обеспечивая цепь передачи. Однако примерно у 4% инфицированных развивается Т-клеточная лейкемия/лимфома взрослых (ATLL). HTLV-1 – это онкоретровирус, который трансформирует CD4+-Т-лимфоциты и дерегулирует лимфопролиферативные пути, что способствует развитию ATLL. Для достижения трансформации клеток большинство онкогенных ретровирусов используют трансдукцию с захватом протоонкогенов, при этом провирусная интеграция нарушает экспрессию опухолевых супрессоров или протоонкогенов. Цель исследования. Мы провели исследование по определению распространенности HTLV-1-инфекции среди доноров крови с целью расширения базы данных HTLV-1, оценки риска передачи вируса через компоненты крови, а также оценки риска персистенции инфекции или развития неопластических заболеваний у носителей HTLV-1. Материалы и методы. Настоящая научная работа – перекрестное исследование доноров крови всех категорий. В исследовании участвовали 265 доноров крови из Национального центра переливания крови в Браззавиле. После тестирования на антитела к HTLV-1 методом ИФА во всех положительных в ИФА-образцах проводили определение провирусной ДНК методом «вложенной» ПЦР, а затем методом количественной ОТ-ПЦР с использованием специфических праймеров p53 и c-myc оценивали экспрессию генов. Результаты. Из 265 доноров 20 человек были положительны по анти-HTLV-1-антителам, у 5 доноров была выявлена провирусная ДНК. Распространенность HTLV-1 составила 1,8%. Все HTLV-1-инфицированные доноры были мужчинами (1,8%), с положительной корреляцией между наличием инфекции и мужским полом (p = 0,05); 1,1% положительных доноров были регулярными, большинство в возрасте от 31 до 45 лет (1,5%), и наиболее часто встречались доноры-совместители (1,1%). Во всех образцах наблюдалась нормальная экспрессия генов p53 и c-myc. Заключение. Распространенность HTLV-1, хотя и низкая, остается значительной проблемой. У HTLV-1-инфицированных доноров не было обнаружено аномальной экспрессии генов p53 или c-myc, что может означать, что ни один из Т-лимфоцитов доноров не был трансформирован HTLV-1.

Adult T-cell leukemia/lymphoma (ATL) occurs after human T-cell leukemia virus type-1 (HTLV-1) infection with a long latency period exceeding several decades. This implies the presence of immune evasion mechanisms for HTLV-1-infected T cells. Although ATL cells have a CD4+CD25+ phenotype similar to that of regulatory T cells (Tregs), they do not always possess the immunosuppressive functions of Tregs. Factors that impart effective immunosuppressive functions to HTLV-1-infected cells may exist. A previous study identified a new CD13+ Treg subpopulation with enhanced immunosuppressive activity. We, herein, describe the paired CD13- (designated as MT-50.1) and CD13+ (MT-50.4) HTLV-1-infected T-cell lines with Treg-like phenotype, derived from the peripheral blood of a single patient with lymphoma-type ATL. The cell lines were found to be derived from HTLV-1-infected non-leukemic cells. MT-50.4 cells secreted higher levels of immunosuppressive cytokines, IL-10 and TGF-β, expressed higher levels of Foxp3, and showed stronger suppression of CD4+CD25- T cell proliferation than MT-50.1 cells. Furthermore, the CD13 inhibitor bestatin significantly attenuated MT-50.4 cell growth, while it did not for MT-50.1 cells. These findings suggest that CD13 expression may be involved in the increased Treg-like activity of MT-50.4 cells. Hence, MT-50.4 cells will be useful for in-depth studies of CD13+Foxp3+ HTLV-1-infected cells.

BackgroundHuman T-cell lymphotropic virus type 1 (HTLV-1) is a neglected virus that can cause severe disease and be transmitted from mother to child through breastfeeding. Avoidance of breastfeeding prevents 80% of vertical transmission. The United Kingdom (UK) is currently assessing whether HTLV-1-targeted antenatal screening should be implemented.AimWe aimed to assess the impact and cost-effectiveness of a targeted programme to prevent HTLV-1 vertical transmission in England and Wales.MethodsWe estimated the number of pregnant women who have high risk of HTLV-1 infection based on their or their partner\'s country of birth. With data from 2021, we used a mathematical model to assess cost-effectiveness of HTLV-1 antenatal screening. We also estimated the annual number of infant infections and the number that could be prevented with screening and intervention.ResultsWe estimate that ca 99,000 pregnant women in England and Wales have high risk of HTLV-1 infection. In the absence of screening, 74 (range: 25-211) HTLV-1 infections in infants would be expected to occur every year in England and Wales. Implementation of targeted screening would prevent 58 (range: 19-164) infant infections annually. The intervention is effective (incremental 0.00333 quality-adjusted life years (QALY)) and cost-saving (GBP -57.56 (EUR -66.85)).ConclusionOur findings support implementation of HTLV-1 targeted antenatal screening to reduce vertical transmission from mothers to infants in the UK.