Lymphotropic Virus Research Articles

Correlation Between TWEAK Serum Level and HTLV-1 Proviral Load in HAM/TSP.

Human T-cell lymphotropic virus type-I (HTLV-I)-associated myelopathy/tropical spastic paraparesis (HAM/TSP), the main neurological manifestation of HTLV-I, is a chronic inflammatory disease. Viral-host interaction and host genetics are two important contributors to the development of the HAM/TSP. This study was conducted to measure the serum level of tumor necrosis factor-alpha-like weak inducer of apoptosis (TWEAK) by ELISA method in three groups of participants including 34 HAM/TSP patients (HAM/TSP), 35 asymptomatic HTLV-1 carriers (ACs), and 20 healthy controls (HCs). Also, the titer of the proviral load in two groups of HAM/TSP and ACs was assessed by the real-time polymerase chain reaction (PCR). The statistical results showed that, there is no significant difference between the three groups in TWEAK cytokine level (p = 0.667). Also, there was no significant difference in proviral load titer between groups of HAM/TSP and ACs (p = 0.08). Furthermore, no significant difference was observed between proviral load and TWEAK cytokine concentration between groups of HAM/TSP and ACs. Our findings showed that despite the inflammatory nature of HAM/TSP disease, the expression level of TWEAK in HAM/TSP patients is not significantly different from the groups of ACs and HCs. Therefore, the involvement of other factors in causing HAM/TSP is not unexpected.

A novel hybrid method with convergence analysis for approximation of HTLV-I dynamics model

This paper presents a novel numerical approach for approximating the solution of the model describing the infection of CD4+T\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$CD4^+T$$\\end{document}-cells by the human T-cell lymphotropic virus I (HTLV-I).The proposed method utilizes the operational matrix along with spectral method to convert the fractional model into a system of nonlinear algebraic equations. The Levenberg-Marquardt algorithm efficiently solves these equations. The study includes theoretical convergence analysis and error bounds to establish the validity of the proposed method. Through several test problems, we demonstrate the effectiveness and accuracy of the approach. We compare its performance and reliability to other existing methods in the literature. The results indicate that the proposed method is a reliable and efficient approach for solving the model.

Human T-cell lymphotropic virus: knowledge of academics from a higher education institution

Objective: To estimate the knowledge of nursing students from two higher education institutions in relation to Human T-cell Lymphotropic Virus. Materials and Methods: This is a quantitative descriptive and cross-sectional study, conducted with nursing students from a higher education institution in Minas Gerais, in October 2023. In this work, it was decided to develop a data collection instrument, applied through an online questionnaire made available by the Google Forms platform. Results: A total of 91 questionnaires were received, of which 81 were validated, and it was observed that 70% of the students stated that they had no knowledge about this virus. However, in the specific questions about the Human T-Cell Lymphotropic Virus, the average rate of correct answers of 58.91% was tabulated and calculated. Conclusion: Thus, since these are future health professionals, this percentage is considered below what is necessary, so it is essential to have a greater involvement of this group with the theme, in order to improve the management of cases, avoiding greater transmissibility of the virus.

Novel diagnostic method for B cell vitreoretinal lymphoma by identification of regulatory T cells and PD-1+ cytotoxic T lymphocytes in the vitreous via flow cytometry

AimsTo investigate the significance of regulatory T cells (Tregs) and programmed cell death 1 (PD-1)+ cytotoxic T lymphocytes (CTLs) in the vitreous of patients with vitreoretinal lymphoma (VRL) and uveitis.MethodsThis...

Cognitive Assessment in HTLV-1 Patients Followed Up at a Reference Center in Salvador, Brazil.

Human T-cell lymphotropic virus type 1 (HTLV-1) is endemic to Brazil, and there is still no specific treatment for these patients. The literature shows that few studies have described the cognitive impairment associated with an HTLV-1 infection, with none of them examining the population of Salvador, where there are approximately forty thousand people infected with the virus. To determine the prevalence of cognitive impairment among individuals with HTLV-1. In addition, investigate whether sociodemographic aspects, time since the diagnosis of infection, and the diagnosis of HTLV-Associated Myelopatia/Tropical Spastic Paraparesis (HAM/TSP) or depression are associated with cognitive impairment in this population. This was an observational, cross-sectional study that consisted of consecutively approaching 100 HTLV-1 patients during outpatient care at a referral center followed by the administration of three questionnaires- the Mini Mental State Examination (MMSE), the Montreal Cognitive Assessment (MoCA), and Beck's Depression Inventory. The prevalence of cognitive impairment found was 71% using the MMSE and 82% using the MoCA. There was a statistically significant association between the cognitive dysfunction and the variables of age and education according to the MoCA analysis but not the MMSE data. Diagnosis of HAM/TSP was correlated with cognitive impairment using the MMSE but not the MoCA. The prevalence of depression was 20%, and there was no association between cognitive impairment and depressive symptoms in these patients. The findings of this study demonstrate a correlation between cognitive dysfunction and HTVL-1 infection, with a more evident involvement of executive functions and memory. Larger studies are needed to clarify the association between cognitive dysfunction, age, education, and the diagnosis of HAM/TSP.

Structure Of The Single Health System For Diagnosis Of Htlv-1/2 In The Northern Region Of Tocantins

Background: The Human T-cell Lymphotropic Virus (HTLV), the first human retrovirus discovered, is associated with oncogenesis and is subdivided into several groups, with types 1 and 2 being the most prevalent and clinically relevant. Its main forms of transmission include unprotected sexual intercourse, blood transfusions, tissue and organ transplants, as well as vertical transmission (mother to newborn). In Brazil, mandatory testing for HTLV was implemented in the 1990s for blood donations and transplants, and expanded in 2024 by Ordinance No. 3,148 of the Ministry of Health, which includes testing during prenatal care. Objective: This study aimed to evaluate the structure of the Unified Health System (SUS) in the municipalities of the far north of Tocantins for the diagnosis of HTLV-1/2. Methodology: This is a qualitative study, in which semi-structured questionnaires were applied to Primary Care professionals and municipal health managers. Results: The results indicated significant deficiencies in knowledge of national protocols and the absence of a structured municipal flow for testing. Conclusion: It can be concluded that the health structure of the municipalities evaluated is insufficient for the effective diagnosis of HTLV-1/2

Sexual transmission of HTLV-1 resulting in uveitis with short-term latency and low proviral load.

Human T-cell Lymphotropic Virus Type 1 (HTLV-1) is traditionally linked to severe conditions such as adult T-cell leukemia/lymphoma, HTLV-1-associated myelopathy, and HTLV-1 uveitis, with vertical transmission, particularly mother to child thorough breastfeeding, considered the primary route. Despite efforts to reduce vertical transmission through antenatal screening in Japan, horizontal transmission has contributed to the rising prevalence of HTLV-1 in metropolitan areas. This case reports the youngest documented instance of HTLV-1 uveitis resulting from horizontal transmission through sexual contact in an 18-year-old woman. The patient presented with blurred vision in her right eye, and a comprehensive ophthalmologic examination identified vitreous opacity and retinal vasculitis. Serological tests confirmed HTLV-1 infection, with a proviral load of 2.66 copies per 100 peripheral blood mononuclear cells, measured by real-time PCR. A differential diagnosis confirmed HTLV-1 uveitis. Further family and partner investigations confirmed horizontal transmission, most likely through sexual contact. Over 6 years of follow-up, the patient experienced multiple recurrences of HTLV-1 uveitis and developed HTLV-1-associated keratopathy. This case highlights the potential for rapid disease progression with relatively low proviral loads and short latency, emphasizing the need for updated public health strategies for sexually active young populations.

HTLV-1 infected T cells cause bone loss via small extracellular vesicles.

Adult T cell leukaemia (ATL), caused by infection with human T- lymphotropic virus type 1 (HTLV-1), is often complicated by hypercalcemia and osteolytic lesions. Therefore, we studied the communication between patient-derived ATL cells (ATL-PDX) and HTLV-1 immortalized CD4+ T cell lines (HTLV/T) with osteoclasts and their effects on bone mass in mice. Intratibial inoculation of some HTLV/T leads to a profound local decrease in bone mass similar to marrow-replacing ATL-PDX, despite the fact that few HTLV/T cells persisted in the bone. To study the direct effect of HTLV/T and ATL-PDX on osteoclasts, supernatants were added to murine and human osteoclast precursors. ATL-PDX supernatants from hypercalcemic patients promoted the formation of mature osteoclasts, while those from HTLV/T were variably stimulatory, but had largely consistent effects between human and murine cultures. Interestingly, this osteoclastic activity did not correlate with expression of osteoclastogenic cytokine receptor activator of nuclear factor kappa-B ligand (RANKL), suggesting an alternative mechanism. HTLV/T and ATL-PDX produce small extracellular vesicles (sEV), known to facilitate HTLV-1 infection. We hypothesized that these sEV also mediate bone loss by targeting osteoclasts. We isolated sEV from both HTLV/T and ATL-PDX, and found they carried most of the activity found in supernatants. In contrast, sEV from uninfected activated T cells had little effect. Analysis of sEV (both active and inactive) by mass spectrometry and electron microscopy confirmed absence of RANKL and intact virus. Viral proteins Tax and Env were only present in sEV from the active, osteoclast-stimulatory group, along with increased representation of proteins involved in osteoclastogenesis and bone resorption. sEV from osteoclast-active HTLV/T injected over mouse calvaria in the presence of low-dose RANKL caused more osteolysis than osteoclast-inactive sEV or RANKL alone. Thus, HTLV-1 infection of T cells can cause release of sEV with strong osteolytic potential, providing a mechanism beyond RANKL production that modifies the bone microenvironment, even in the absence of overt leukaemia.

267 - Darifenacin versus Parasacral Transcutaneous Electrical Nerve Stimulation for Overactive Bladder Syndrome in Patients Infected With Human T-Cell Lymphotropic Virus 1 – Preliminary Results of a Randomized Clinical Trial

267 - Darifenacin versus Parasacral Transcutaneous Electrical Nerve Stimulation for Overactive Bladder Syndrome in Patients Infected With Human T-Cell Lymphotropic Virus 1 – Preliminary Results of a Randomized Clinical Trial

Cytotoxicity of bendamustine, alone and in combination with novel agents, toward adult T-cell leukemia cells.

Adult T-cell leukemia/lymphoma (ATL) develops from the infection of T cells with human T lymphotropic virus type 1 (HTLV-1). There are an estimated 5-20 million HTLV-1 carriers worldwide and the patients are frequently observed in subtropical Africa, the Caribbean, Middle East, South America, and South West Japan. The prognosis of ATL remains dismal due to rapid acquired resistance to treatment with cytotoxic chemotherapeutic agents. In particular, the development of novel therapies for relapsed or refractory (R/R) ATL is an unmet need. Previous clinical trials revealed that bendamustine (BDM) was effective as the first-line treatment for indolent lymphoma and R/R cases of diffuse large B-cell lymphoma. Its major advantage is that it has few side effects such as hair loss and peripheral neuropathy, and does not impair the quality of life. However, its efficacy has not been verified for ATL in pre-clinical or clinical studies. In this study, we have shown the cytotoxicity of BDM alone and in combination with novel agents including the histone deacetylase (HDAC) inhibitor tucidinostat, the enhancer of zeste homolog 1/2 (EZH1/2) dual inhibitor valemetostat, and the Bcl2 family inhibitor ABT-737. The combined in vitro effects of BDM and tucidinostat were reproduced in a murine model without any obvious hematological toxicity. Our present results suggest that the combination of tucidinostat and BDM could additively prolong the survival of patients with R/R progressive ATL. The efficacy and safety of this combination are thus worthy of investigation in clinical settings.

Immunophenotypic, genetic, and clinical characterization of adult T-cell leukemia/lymphoma: A single tertiary care center experience in the United States.

Adult T-cell leukemia/lymphoma (ATLL) is an aggressive mature T-cell neoplasm caused by human T-cell lymphotropic virus type 1 (HTLV-1). Its most common immunophenotype is CD4+/CD7-/CD25+, although unusual immunophenotypes can occur and may lead to misdiagnosis. The immunophenotypes, cytogenetics, molecular features, clinical presentations, treatment, and prognosis of 131 patients with ATLL were retrospectively studied in a large tertiary medical center in the United States. All cases showed loss of CD7 expression. While 82.4% of cases demonstrated CD4+, 17.6% exhibited unusual phenotypes, including CD4+/CD8+ (6.9%), CD4-/CD8- (2.3%), CD5- (3.1%), CD2-, and CD3-. The most common cytogenetics abnormalities included polysomy 3 (34.6%), translocation 1 (23.1%), and abnormalities found on chromosome 11 (30.8%) and chromosome 14 (26.9%). The common gene mutations identified by the next-generation sequencing study were TP53 (16.7%), TBL1XR1 (16.7%), EP300 (14.3%), and NOTCH1 (14.3%). TBL1XR1 mutation is associated with genetic instabilities. There was no significant difference between the clinical presentations of these 2 groups. Adult T-cell leukemia/lymphoma exhibits versatile immunophenotypic, cytogenetic, and molecular features. Simultaneous involvement of blood, lymph nodes, and other organs, along with hypercalcemia in a patient from an endemic area, necessitates HTLV-1 testing to avoid underdiagnosis of this dismal disease that might need aggressive chemotherapy followed by bone marrow transplant.

Urodynamic findings and vibegron effects on neurogenic lower urinary tract dysfunction caused by human T-cell leukemia virus type I-associated myelopathy/tropical spastic paraparesis.

Human T-cell lymphotropic virus type 1 infection can cause HTLV-1-associated myelopathy/tropical spastic paraparesis, characterized by spastic paralysis of both lower limbs. More than 90% of HAM/TSP patients show lower urinary tract symptoms and dysfunction. A 27-year-old woman diagnosed with HAM/TSP presented with overactive bladder. A urodynamic study revealed detrusor overactivity. OAB remained despite improvements in spastic paralysis of the lower limbs after starting prednisolone. The addition of solifenacin likewise failed to improve OAB or DO in this patient. Switching from solifenacin to vibegron improved OAB symptoms. In patients for whom OAB and DO do not improve with steroid treatment and solifenacin, treatment with vibegron may improve OAB symptoms.

A Systematical Review on ART Use in HTLV Infection: Clinical, Virological, and Immunological Outcomes.

Human T-cell lymphotropic virus (HTLV) infection affects over ten million people worldwide, but there is no effective treatment so far. This review describes the virological, immunological, and clinical outcomes of antiretroviral therapy (ART) in people with HTLV infection. This systematic review followed PRISMA reporting guidelines and was registered in PROSPERO: CRD42022350076. The Newcastle-Ottawa Scale, adapted for cross-sectional studies, and Rob-2 were used to assess the methodological quality of these studies. Systematic searches were conducted in the Medline (PubMed), Scopus (Elsevier), Cochrane Library, and Web of Science (Clarivate Analytics) databases. We retrieved data from eight methodologically diverse articles on treatment of patients infected by HTLV-1 or HTLV-2 alone, or coinfected by HIV-1, who received Raltegravir, Tenofovir, Lamivudine, or Zidovudine. The proviral load decreased in three out of seven studies over 4 to 48 weeks of antiretroviral use. Cellular immune response (CD4, CD8, CD25, CD69, and CD71 cells) was evaluated in six studies. While no significant clinical improvement was observed, all studies reported clinical stability during treatment. Despite the demonstrated antiviral activity of ART, in vitro, clinical improvement was not proven. Most studies showed disease stability during ART use, suggesting potential clinical benefits. There is a need of larger, well-controlled trials to define the role of ART in the treatment of HTLV infection.

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.

Epidemiology and ecology of the sylvatic cycle of African Swine Fever Virus in Kenya

African Swine Fever (ASF) is caused by a DNA virus (AFSV) maintained and transmitted by the Argasid ticks. The re-emergence of the disease in Africa coupled with its rapid spread globally is a threat to the pig industry, food security and livelihoods. The ecology and epidemiology of the ASFV sylvatic cycle, especially in the face of changing land use and land cover, further compounds the menace and impacts of this disease in Kenya. The study aimed to determine the occurrence and distribution of ASFV seroprevalence in warthog populations, the tick vectors and extent of tick infestation of warthog burrows, and the genotypes of ASFV in soft ticks in Kenya. Warthogs from different parts of Kenya were captured and venous blood was centrifuged to harvest sera. Warthog burrows were examined for their conditions and to extract ticks. Sera were analyzed for antibodies against ASFV using a commercial ELISA kit coated with p32 ASFV recombinant protein. Ticks were pooled, DNA extracted and the p72 gene of the ASFV was amplified by qPCR and conventional PCR. The overall seroprevalence of ASFV in warthogs was 87.5 %. A total of 228 warthog burrows were examined and 2154 argasid ticks were extracted from the burrows. Tick pools from Kigio Farm and Lewa Wildlife Conservancies were ASFV-positive by qPCR and conventional PCR. ASFV was further confirmed by the Twist Comprehensive Viral Research Panel (TCVRP), which also identified the argasid ticks as Ornithodoros porcinus. The ticks were infected with virus genotype IX, and their occurrence overlaps with regions of previous ASF outbreaks in domestic pigs. Further, Viruses that could be tick endosymbionts/commensals or due to bloodmeal were detected in ticks by TCVRP; Porcine type-C oncovirus; Pandoravirus neocaledonia; Choristoneura fumiferana granulovirus; Enterobacteria phage p7; Leporid herpesvirus 4 isolate; 5; Human Lymphotropic virus; Human herpesvirus 5. In conclusion, our results suggest that infected Ornithodoros spp. seems to have a rich virome, which has not been explored but could be exploited to inform ASF control in Kenya. Further, the ecology of Ornithodoros spp. and burrow-use dynamics are complex and more studies are needed to understand these dynamics, specifically in the spread of ASFV at the interface of wild and domestic pigs. Further, our results provide evidence of genotype IX ASFV sylvatic cycle which through O. porcinus tick transmission has resulted in high exposure of adult common warthogs. Finally, the co-circulation of ASFV genotype IX in the same location with past ASF outbreaks in domestic pigs and presently in ticks brings to focus the role of the interface and ticks on virus transmission to pigs and warthogs.

High level of genomic divergence in orf-I p12 and hbz genes of HTLV-1 subtype-C in Central Australia

BackgroundHuman T cell lymphotropic virus type 1 (HTLV-1) infection remains a largely neglected public health problem, particularly in resource-poor areas with high burden of communicable and non-communicable diseases, such as some remote populations in Central Australia where an estimated 37% of adults are infected with HTLV-1. Most of our understanding of HTLV-1 infection comes from studies of the globally spread subtype-A (HTLV-1a), with few molecular studies reported with the Austral-Melanesian subtype-C (HTLV-1c) predominant in the Indo-Pacific and Oceania regions.ResultsUsing a primer walking strategy and direct sequencing, we constructed HTLV-1c genomic consensus sequences from 22 First Nations participants living with HTLV-1c in Central Australia. Phylogenetic and pairwise analysis of this subtype-C proviral gDNA showed higher levels of genomic divergence in comparison to previously published HTLV-1a genomes. While the overall genomic homology between subtypes was 92.5%, the lowest nucleotide and amino acid sequence identity occurred near the 3′ end of the proviral genome coding regulatory genes, especially overlapping hbz (85.37%, 77.46%, respectively) and orf-I product p12 (82.00%, 70.30%, respectively). Strikingly, the HTLV-1c genomic consensus sequences uniformly showed a defective translation start codon for the immune regulatory proteins p12/p8 encoded by the HTLV-1A orf-I. Deletions in the proviral genome were detected in many subjects, particularly in the structural gag, pol and env genes. Similarly, using a droplet digital PCR assay measuring the copies of gag and tax per reference host genome, we quantitatively confirmed that provirus retains the tax gene region at higher levels than gag.ConclusionsOur genomic analysis of HTLV-1c in Central Australia in conjunction with earlier Melanesian HTLV-1c sequences, elucidate substantial differences with respect to the globally spread HTLV-1a. Future studies should address the impact these genomic differences have on infection and the regionally distinctive frequency of associated pulmonary disease. Understanding the host and virus subtype factors which contribute to the differential morbidity observed, is crucial for the development of much needed therapeutics and vaccine strategies against this highly endemic infection in remote First Nations communities in Central Australia.

Leukemia-Related Signaling Pathways Among HTLV-1-Derived Adult T Cell Leukemia/Lymphoma and Asymptomatic Carriers in Comparison to Normal Group.

Human T cell lymphotropic virus type 1 (HTLV-1) is associated with adult T cell leukemia/lymphoma (ATLL), a fetal malignant infection. Recently, HTLV-1 new asymptomatic carriers (ACs) have frequently been reported among blood donors. Reaching the profound concept of HTLV-1-associated molecular pathogenesis could result in finding novel therapeutic strategies. The current study aimed to determine leukemia-related signaling regulation in ATLL. Thirty participants were evaluated in 3 groups, including 10 ATLL patients, 10 ACs, and 10 normal controls. Blood samples were isolated without any chemotherapy history from ATLL patients. Also, blood samples were recovered from ACs and normal individuals. White blood cells isolation was done on the collected blood samples. After this, RNA was extracted from the prepared samples and used for the cDNA synthesis. TAX and HTLV-1 basic leucine zipper factor as viral genes and cellular genes, including MKP-1, EVI-1, JNK-1, FOXO-1, AKT-1, DEPTOR, MTOR, and JUN, were investigated using real-time PCR. The mean age of ATLL patients was 53.2 ± 7.32 years, and 9 (90%) were male. The EVI-1 and FOXO-1 expression levels were significantly associated with ATLL patients compared with the internal control. However, the significant differences in expression of other genes in the remaining groups were not seen. Discovering viral and cellular signaling pathways that regulate HTLV-1 transformation is essential. A novel therapeutic strategy for ATLL-regulating cellular signaling pathways invivo could be considered. Therefore, clinical trials using activators and inhibitors of related cellular signaling pathways for cell therapy of ATLL are recommended. It is recommended that more investigation be conducted on FOXO-1 and EVI-1 to target these genes and reveal the molecular pathogenesis of ATLL.

Association between HTLV-1/2 infection and COVID-19 severity in a migrant Shipibo-Konibo population in Lima, Peru.

The migrant community of the Shipibo-Konibo indigenous people in Lima, Peru were extremely vulnerable during the COVID-19 pandemic. Additionally, infection with human T-cell lymphotropic virus type 1 and 2 (HTLV-1/2) is endemic in this population causing immunosuppression. The aim of the study was to describe the association between HTLV-1/2 infection and the clinical severity of COVID-19. This was a cross-sectional descriptive study involving a survey of adult Shipibo-Konibo indigenous migrants residing in Cantagallo-Rímac who were identified as suspected or confirmed cases of COVID-19. Blood samples were collected for SARS-CoV-2 antibody and HTLV-1/2 ELISA testing. A confirmatory Western Blot test was performed for those with a positive ELISA test. A total of 182 individuals were surveyed and sampled. No significant association was found between HTLV-1/2 infection and the clinical severity of COVID-19. The prevalence of HTLV-1/2 was 8.8% (95%CI: 5.0-14.1) with Western Blot. Age was the only statistically significant risk factor for developing a more severe form of COVID-19 (OR: 1.03; 95%CI: 1.00-1.06; p = 0.032). There was no association found between HTLV-1/2 infection and the clinical severity of COVID-19. The prevalence of HTLV-1/2 infection in the Shipibo-Konibo population is high and warrants continuous monitoring in the advent of other infectious disease outbreaks and the development of HTLV-associated comorbidities.

High HTLV-1 Proviral Load Predates and Predicts HTLV-1-Associated Disease: Literature Review and the London Experience.

Human T cell lymphotropic virus type 1 (HTLV-1) is a retrovirus that infects lymphocytes and causes severe diseases. HTLV-1 proviral load (PVL), i.e., the number of host cells that carry HTLV-1 proviral DNA integrated into their genome, can be measured in peripheral blood mononuclear cells (PBMCs) using quantitative polymerase chain reaction. In this narrative review, we discuss the usefulness of HTLV-1 PVL quantification and share our experience acquired during more than 30 years of follow-up of people living with HTLV-1 in the UK. Patients with HTLV-1-associated myelopathy have higher PVL than those with asymptomatic infection. This is consistent across studies in different countries. High PVL predates symptom onset for both inflammatory and proliferative diseases. High PVL is essential but not sufficient for the development of HTLV-1-associated diseases. Therefore, PVL quantification can be used to support the care of people living with HTLV-1 by identifying those most at risk of HTLV-1-associated diseases.

Imbalanced IL10/TGF-β production by regulatory T-lymphocytes in patients with HTLV-1-associated myelopathy/ tropical spastic paraparesis

BackgroundHuman 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.MethodsAsymptomatic 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.ResultsTotal 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.ConclusionsA 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.