Human T-lymphotropic virus type 1 (HTLV-1) is associated with neurological, degenerative, and inflammatory diseases. Brazil has regions with high prevalence rates. The prevalence among relatives of positive people is high, and intrafamily transmission causes the conservation of the infection for different generations. The investigation of epidemiological and molecular factors may clarify the factors associated with the efficacy of intrafamilial transmission of HTLV-1. Objective: To analyze the epidemiological and molecular factors associated with intrafamilial transmission of HTLV-1 in an endemic area of Brazil. Material and Methods: A cross-sectional study investigated 72 relatives from 14 families with more than one infected. Epidemiological data were collected from all family members, and genetic sequencing was performed, phylogenetic analysis of 22 positive relatives. Results: The prevalence of HTLV-1 in families with infected people was 56.94% (41/72). Twelve vertical transmission routes and ten horizontal transmission routes were identified. Phylogenetic analysis demonstrated the absence of polymorphisms between infected mother and child sequences, while sequences of couples presented nucleotide divergence of up to 3%.among themselves. It was also identified in a family with an intrafamilial transmission with the occurrence of two viral strains. Conclusion: Molecular data confirmed intrafamilial transmission. They also indicated little genetic variability between the sequenced samples of family members and those deposited in GenBank used in this study. The absence of polymorphisms was observed in cases of vertical transmission, indicating a tendency to perpetuate identical sequences regardless of the time of acquisition of the infection.

The inaugural AIDS Program in Brazil was established in São Paulo in 1983, with the Instituto Adolfo Lutz appointed for laboratory assistance. Subsequently, research on HIV infections and HIV/HTLV (HIV/HTLV-1 and HIV/HTLV-2) co-infections were conducted. This narrative review focuses on studies from the Immunology Department (1983–2017) that significantly influenced AIDS diagnosis or provided epidemiological data such as prevalence rates, sex, age, and risk factors. Ten studies, encompassing over 8,000 individuals, are discussed. During 1983–1985, nearly all AIDS cases were attributed to homosexual/bisexual men aged 31 years old. Subsequently, heterosexual men and women emerged as risk groups owing to intravenous drug use (IDU) and/or unprotected sexual intercourse with AIDS patients or multiple partners per year. From 1985 onwards, vertical transmission led to child infections. HIV/HTLV co-infection rates decreased over time, initially associated with male IDU, and in the 2010s, with females, IDU, and individuals aged >40 years. Trends in HIV and HIV/HTLV co-infections among younger men and women (<30 years of age) were observed from 2015–2017. The changing characteristics and risk groups for HIV and HIV/HTLV co-infections over the years underscore the necessity for ongoing public policies to prevent retrovirus transmission, particularly among adolescents and young adults.

Recent studies revealing varied responses of infected cells to LRAs underscore the limited effectiveness of these agents and emphasize the wide array of determinants contributing to the heterogeneity of reservoirs, including virus genetic background, cell model, cell type, silencing mechanisms, tissue reservoirs, integration sites, patient, and gender specific factors. The enhancer region of the HIV-1 LTR contains two adjacent NF-κB binding sites that play a central role in mediating inducible HIV-1 gene expression. Beyond the involvement of various transcription factors, such as NF-κB, epigenetic constraints also play a pivotal role in suppressing the initiation of latent HIV transcription. Consequently, even latent viruses containing functional NF-κB sites remain unresponsive to drugs that activate NF-κB. Thus, it is evident that the activation of NF-κB alone does not suffice to trigger latent HIV, contradicting the central hypothesis of this study. The author used bioinformatics methods to analyze the viral proteins and their primer binding sites. The results show that the amino acid sequence ARG of Gag proteins of HTLV-1, HTLV-2, STLV-1 and STLV-2 match their primer binding site GGGGGCTCG in the 3'-to-5' direction and that the amino acid sequence SPR of Gag proteins of HIV-1, HIV-2, SIV and FIV match their primer binding site GGCGCCCGA in the 3'-to-5' direction. Related studies have shown that the genomic Gag/Gag-Pol complex recruits the LysRS/tRNA complex. The selective packaging of the tRNA primer requires HIV-1 Gag and Gag-Pol, and an interaction between LysRS and Gag is observed in vitro. In HIV-1, Gag/LysRS interaction depends on Gag sequences within the CTD of CA around amino acids 283-363 and motif 1 of LysRS around amino acids 208-259. It should be noted that the amino acid sequence SPR of the Gag protein is located at amino acids 148-150 within the NTD of CA, specifically at the NTD-NTD interface 1. Although this research is purely bioinformatics analysis, the relevant studies have demonstrated that Gag proteins match the HIV-1 primer binding site and possess the potential to directly activate dormant retroviruses.

Before the adaptive immune response is established, retroviruses can be targeted by several cellular host factors at different stages of the viral replication cycle. This intrinsic immunity relies on a large diversity of antiviral processes. In the case of HTLV-1 infection, these active innate host defence mechanisms are debated. Among these mechanisms, we focused on a RNA decay pathway called nonsense-mediated mRNA decay (NMD), which can target multiple viral RNAs, including HTLV-1 unspliced RNA, as it has been recently demonstrated. NMD is a cotranslational process that depends on the RNA helicase UPF1 and regulates the expression of multiple types of host mRNAs. RNA sensitivity to NMD depends on mRNA organization and the ribonucleoprotein (mRNP) composition. HTLV-1 has evolved several means to evade the NMD threat, leading to NMD inhibition. In the early steps of infection, NMD inhibition favours the production of HTLV-1 infectious particles, which may contribute to the survival of the most fit clones despite genome instability; however, its direct long-term impact remains to be investigated.

BACKGROUND: During the natural history, the incidence HTLV-1 related diseases were 0.5% until 10% after decades of infection. Despite relative low lethality, previous study observed that HTLV-1 infection is associated with significantly increased mortality. For example, the incidence of ATLL and HAM/TSP, co-infections with HIV and HCV, parasitic co-infection with Strongyloides stercoralis may increase morbidity and mortality. OBJECTIVE: Determine the mortality rate and its major variables as possible risk factors, analyzing the HTLV Clinic at Emilio Ribas Institute, a continuous open cohort of HTLV patients since 1997. METHODS: This cohort open cohort possesses new patients added at a rate of approximately 50 patients/year. There were 1100 HTLV-infected subjects identified by September 30th 2018. All clinical data including clinical and laboratory data, which have been updated on a regular basis over the last 22 years, were entered into a specific REDCap database. The Ethical Board of the IIER approved the protocol. RESULTS: Along 22 years of clinical care in the HTLV-out clinic, 727 HTLV-1-infected subjects and 248 HAM/TSP cases. Four-hundred sixty-eight patients of whom remaining under active follow up. The mean follow-up time of the cohort was 12 years. Twenty-seven patients died (median age of 51,5 years old). From this total, 13 was asymptomatic carriers and 14 HAM/TSP subjects, 12 of asymptomatic and seven HAM/TSP possess co-infected with HIV or/and HCV. Other seven presented HAM/TSP without co-infection, and all was female, and sepsis was the majority cases the majority of cases of sepsis were related to infection of the urinary tract (p=0.058) and to ulcers of decubitus (p=0.021), and it was associated with risk factors for mortality. CONCLUSIONS: Overall, the mortality rate for HAM-TSP patients was six percent. The mean life expectancy in Brazil is about 78 years in 2018, twenty-two years higher than HAM/TSP patients without any other coinfection. This study highlights the possibility of higher death risk among HTLV-1-infected patients and HAM/TSP subjects in Brazil, and identified some risk factors for this outcome. Also, these patients may possess higher risk for morbidity, usually urinary tract infections and decubitus scars, which could increase risk for death.

Background: The prevalence of human T-lymphotropic virus type-1 (HTLV-1) infection is higher in women, and sexual intercourse has been described as an important route of male-to-female transmission. The present study aimed to quantify HTLV-1 proviral load (PVL) in vaginal fluid, and to investigate correlations with PVL in peripheral blood mononuclear cells (PBMC). Methods: HTLV-1-infected women were consecutively recruited at a multidisciplinary center for HTLV patients in Salvador-Brazil. All women underwent gynecological examinations to obtain cervicovaginal fluid and venipuncture for blood collection. PVL, as measured by real-time quantitative polymerase chain reaction (RT-qPCR), was expressed as the number of copies of HTLV-1/106 cells in blood and vaginal fluid samples. Light microscopy was used to assess cervicovaginal cytopathology and vaginal microbiota. Results: In the 56 included women (43 asymptomatic carriers and 13 diagnosed with HTLV-associated myelopathy/tropical spastic paraparesis-HAM/TSP), mean age was 35.9 (SD±7.2) years. PVL was higher in PBMCs [median: 23,264 copies/106 cells (IQR: 7,420 - 64,371)] than in vaginal fluid [451.9 copies/106 cells (IQR: 0 - 2,672)] (p<0.0001). PVL in PBMCs was observed to correlate directly with PVL in vaginal fluid (R=0.32, p=0.01). PVL was undetectable in vaginal fluid samples from 20 women (35.7%), most of whom were asymptomatic (19/20). Cytopathologic analyses revealed no differences between women with detectable or undetectable PVL. Conclusion: HTLV-1 proviral load is detectable in vaginal fluid and correlates directly with proviral load in peripheral blood. This finding suggests that sexual transmission of HTLV-1 from female to male may occur and vertical transmission, particularly in the context of vaginal delivery.

Purpose To investigate secondary glaucoma resulting from uveitis in a patient infected with Human T-cell Leukemia Virus Type 1 (HTLV-1) pathologically and discuss the management of glaucoma with recurrent uveitis. Clinical course An octogenarian woman diagnosed as a carrier of HTLV-1 experienced recurrent uveitis and a sudden rise in intraocular pressure (IOP) in both eyes. Due to the uncontrolled IOP and severely damaged visual field in her left eye, a combined procedure of trabeculectomy and DGIS (Glaucoma drainage implant surgery, Baerveldt 350) was performed. The presence of HTLV-1 provirus was detected in the aqueous humor. Her trabeculectomy sample was processed for light microscopic observation. Following an irregular follow-up, she presented with a sudden decrease in vision and pain in her fellow eye, four years after the glaucoma surgeries. Her right eye exhibited a significant accumulation of mutton-fat-like keratic precipitates. Results Clinical manifestations revealed the presence of granulomatous uveitis. The combined glaucoma surgery, along with continuous topical corticosteroid medication post-surgery in her left eye, effectively suppressed the high IOP spikes and the recurrence of uveitis for 4 years. The pathological examination of the outflow pathways showed a range of damages in Schlemm's canal (SC), including SC endothelial loss, narrowing, and occlusion, as well as loss of trabecular meshwork (TM) cells and fused TM beams. Conclusion Combined GDIS and trabeculectomy represents a promising approach for managing such refractory cases of secondary glaucoma. The continuous topical corticosteroid medication is strongly recommended to prevent irreversible changes in SC and TM associated with granulomatous uveitis.

Small RNAs (sRNA) are epigenetic regulators of essential biological processes that have been linked to the onset and progression of leukemia, including acute adult T-cell leukemia-lymphoma (ATLL) caused by the retrovirus Human T-lymphotropic virus type 1. Here, we describe the sRNA profile of a 30-year-old female with ATLL at diagnosis and after maintenance therapy, with the goal of correlating their expression levels with response to therapy.

Adult T-cell leukemia (ATL) is an aggressive hematologic disease caused by human T-cell leukemia virus type 1 (HTLV-1) infection. Various animal models of HTLV-1 infection/ATL have been established to elucidate the pathogenesis of ATL and develop appropriate treatments. For analyses employing murine models, transgenic and immunodeficient mice are used because of the low infectivity of HTLV-1 in mice. HTLV-1 Tax and HBZ transgenic mice spontaneously develop tumors, and roles for both Tax and HBZ in cell transformation and tumor growth have been established. Severely immunodeficient mice were able to engraft ATL cell lines and have been used in preclinical studies of candidate molecules for the treatment of ATL. HTLV-1-infected humanized mice with an established human immune system are a suitable model to characterize cells in the early stages of HTLV-1 infection. This review outlines the characteristics of mouse models of HTLV-1 infection/ATL and describes progress made in elucidating the pathogenesis of ATL and developing related therapies using these mice.

Human T-lymphotropic virus type 1 (HTLV-1)–associated myelopathy/tropical spastic paraparesis (HAM/TSP) is a slowly progressive spinal cord disorder with no effective treatment. There is much of interest in developing potential biomarkers for predicting the pathogenesis of HAM/TSP disorder. This study used Illumina massive parallel sequencing (MPS) technology to assess the cellular global noncoding RNAome expression profile in HAM/TSP patients (n = 10), asymptomatic HTLV-1 infected carriers (ASP, n = 8), and a second group of healthy controls (n = 5). Using various bioinformatics tools, the sRNA MPS reads were aligned, annotated, and profiled. There were 251 known and 50 potential novel sRNAs among the 402 detected sRNAs in the HAM and ASP groups versus the HC group. Sixty-eight known sRNAs were found to be significantly different between the ASP and HAM groups. In HAM vs ASP subjects, 88 mature miRNAs were downregulated. Three of these miRs (hsa-miR-185-5p, 32-5p, and 192-5p) have the potential to be used as biomarkers for predicting the pathogenesis of HAM/TSP. The top seven deregulated miRS target genes were linked to a variety of biological processes and molecular functions. Relevant reactome pathways to our findings provide a rich source of data and an opportunity to further understand sRNA regulation and function in HTLV-1 pathophysiology.

The human T-cell leukemia virus type 1 (HTLV-1) is the only known human oncogenic retrovirus. HTLV-1 can cause a cancer called adult T-cell leukemia/lymphoma (ATL). The virus is transmitted through body fluids of infected individuals, primarily breast milk, blood, and semen. At least 5–10 million people in the world are infected with HTLV-1. In addition to ATL, HTLV-1 infection can also cause HTLV-I-associated myelopathy (HAM /TSP). ATL is characterized by low viral ex-pression and poor prognosis. The oncogenesis triggered by HTLV-1 is extremely complex and the molecular mechanisms are not fully understood. However, viral regulatory proteins Tax and HTLV-1 bZIP factor (HBZ) have been shown to play key roles in the transformation of HTLV-1-infected T cells. Moreover, several studies have shown that the final fate of HTLV-1-infected transformed T cell clones is the result of a complex interplay of HTLV-1 oncogenic protein expression with cellular transcription factors that subvert the cell cycle and disrupt reg-ulated cell death, thereby exerting their transforming effects. This review provides updated in-formation on the mechanisms underlying the transforming action of HTLV-1 and the potential therapeutic targets to combat ATL.

With an estimated 10 million people infected, the deltaretrovirus human T-cell lymphotropic virus type 1 (HTLV-1) is the second most prevalent pathogenic retrovirus in humans after HIV-1. Like HIV-1, HTLV-1 overwhelmingly persists in a host via a reservoir of latently infected CD4+ T cells. Although most patients are asymptomatic, HTLV-1-associated pathologies are often debilitating and include childhood infective dermatitis and adult T-cell leukaemia/lymphoma (ATLL), which presents in mature adulthood and is associated with poor prognosis with short overall survival despite treatment. Curiously, the strongest indicator for the development of ATLL is the acquisition of HTLV-1 through breastfeeding. There are no therapeutic or preventative regimens for HTLV-1. However, antiretrovirals (ARVs), which target the essential retrovirus enzymes, have been developed for and transformed HIV therapy. Since the architectures of retroviral enzyme active sites are highly conserved, some HIV-specific compounds may be active against HTLV-1. Here, we expand on our work showing that integrase strand transfer inhibitors (INSTIs) and some nucleoside reverse transcriptase inhibitors (NRTIs) block HTLV-1 transmission in cell culture. Specifically, we find that dolutegravir, the INSTI currently recommended as the basis of all new combination antiretroviral therapy prescriptions, and the latest prodrug formulation of the NRTI tenofovir, tenofovir alafenamide, also potently inhibit HTLV-1 infection in cell culture. Our results, if replicated in a clinical setting, could see transmission rates of HTLV-1 and future caseloads of HTLV-1-associated pathologies like ATLL dramatically cut via the simple redistribution of already widely available HIV pills to HTLV-1 endemic areas. Considering our findings with the old medical saying ‘it’s better to prevent than cure’, we highly recommend the inclusion of INSTIs and tenofovir prodrugs in upcoming HTLV-1 clinical trials as potential prophylactics.

Human oncoviruses are able to subvert telomerase function in cancer cells through multiple strategies. The activity of the catalytic subunit of telomerase (TERT) is commonly enhanced in virus-related cancers. Viral oncoproteins, such as high-risk human papillomavirus (HPV) E6, Epstein-Barr virus (EBV) LMP1, Kaposi sarcoma-associated herpesvirus (HHV-8) LANA, hepatitis B virus (HBV) HBVx, hepatitis C virus (HCV) core protein and human T-cell leukemia virus-1 (HTLV-1) tax protein, interact with regulatory elements in the infected cells and contribute to the transcriptional activation of TERT gene. Specifically, viral oncoproteins have been shown to bind TERT promoter, to induce post-transcriptional alterations of TERT mRNA and to cause epigenetic modifications, which have important effects on the regulation of telomeric and extra-telomeric functions of the telomerase. Other viruses, such as herpesviruses, operate by integrating their genomes within the telomeres or by inducing alternative lengthening of telomeres (ALT) in non-ALT cells. In this review, we recapitulate recent findings on virus-telomerase/telomeres interplay and the importance of TERT-related oncogenic pathways activated by cancer causing viruses.