HTLV-1-associated myelopathy/tropical spastic paraparesis

Blood-borne viruses and neurological manifestations: An overview

Infections caused by blood-borne viruses, such as human immunodeficiency virus (HIV), human T-lymphotropic virus (HTLV), hepatitis C virus (HCV), and hepatitis B virus (HBV), are systemic diseases that can lead to a wide range of pathological manifestations. Besides causing severe immune and hepatic disorders, these viral pathogens can also induce neurological dysfunctions via both direct and indirect mechanisms. Neurological dysfunctions are one of the most common manifestations caused by these viruses that can also serve as indicators of their infection, impacting the clinical presentation of the disease. The main neurological manifestations of these blood-borne viral pathogens consist of several central and peripheral nervous system (CNS and PNS, respectively) dysfunctions. The most common neurological manifestations of HIV, HTLV, HCV, and HBV include HIV-associated peripheral neuropathy (PN), HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP), and HCV-/HBV-associated PN, respectively. Nonetheless, patients infected with these viruses may experience other neurological disorders, either associated with these conditions or manifesting in isolation, which can often go unnoticed or undiagnosed by physicians. The present review aims to provide an overview of the latest evidence on the relationship between blood-borne viruses and neurological disorders to highlight neurological conditions that may be somewhat overlooked by mainstream literature and physicians.

Multicenter, randomized, double-blind, placebo-controlled phase 3 study of mogamulizumab with open-label extension study in a minimum number of patients with human T-cell leukemia virus type-1-associated myelopathy

Human T-cell leukemia virus type 1 (HTLV-1)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is a chronic neurodegenerative disease. This multicenter, randomized phase 3 study evaluated the efficacy and safety of 0.3 mg/kg intravenous mogamulizumab, a monoclonal antibody targeting-CC chemokine receptor 4, every 12 weeks in HAM/TSP patients. This study comprised a 24-week double-blind, placebo-controlled period, 24-week open-label period, and extension treatment period. The primary endpoint was the proportion of patients with a ≥ 1-grade improvement in the Osame motor disability score (OMDS). Secondary endpoints were changes in HTLV-1 proviral load, 10-m timed walk, cerebrospinal fluid (CSF) neopterin levels, and safety. The exploratory endpoint was CSF chemokine C-X-C motif ligand 10 (CXCL10) levels. Thirty-four and 33 patients were randomized to mogamulizumab and placebo arms, respectively. At the end of the double-blind period, no significant difference was found in the OMDS improvement rate or other secondary efficacy endpoints assessing motor activities. However, the mogamulizumab arm showed a significant decrease in HTLV-1 proviral load (- 59.39 ± 29.91% vs. placebo 2.32 ± 36.31%) and CSF neopterin (p < 0.001)/CXCL10 levels (p = 0.004). The baseline OMDS pattern and the 60-80% HTLV-1 proviral load reduction were sustained through the open-label and extension treatment periods. Although a higher incidence of rash (69.2%) was reported, the safety profile was similar compared with a previous phase 1/2a study. We found no significant difference in clinical benefit; however, mogamulizumab may provide long-term clinical benefit by preventing disease progression, as CSF neopterin/CXCL10 levels are associated with long-term prognosis in HAM/TSP.Clinical Trial Registration Number: NCT03191526 (registered date: 6-June-2017).

HTLV-1-Associated Myelopathy (HAM) Incidence in Asymptomatic Carriers and Intermediate Syndrome (IS) Patients

Several studies suggest that HTLV-1 infection may be associated with a wider spectrum of neurological and clinical manifestations that do not meet diagnostic criteria for HAM. These conditions may later progress to HAM or constitute an intermediate clinical form: intermediate syndrome (IS), a mid-point between asymptomatic HTLV-1 carriers and those with full myelopathy. Thus, we determined the incidence of HAM cases in the HTLV-1-asymptomatic and IS patients, and the clinical/laboratory associated markers. A total of 204 HTLV-1-positive patients were included in this study, divided into two groups: Group 1, including 145 asymptomatic HTLV-1 subjects (ASY), and Group 2, including 59 patients with inflammatory clinical symptoms in more than three systems and a high proviral load (PVL). During a 60-month follow-up time, with the age ranging from 47 to 79 years, ten patients of the fifty-nine initially diagnosed as IS developed HAM (iHAM), and two patients of the initial 145 ASY developed HAM directly. Women were more prevalent in all groups. For the iHAM patients, the age ranged from 20 to 72 years, with a mean of 53 (±15 SD). Older age was associated with the development of HAM, higher PVL and IS; however, there was no any specific symptom or clinical sign, that was associated with risk for iHAM. In conclusion, IS cases could be an early phase of development of HAM. These findings show the presence of higher incidence probabilities in our cohort than previously reported.

Lived Experience of Human T-cell Leukemia Virus type-1 -Associated Myelopathy/Tropical Spastic Paraparesis (HAM/TSP): A Phenomenology Study

Background

Human T-cell Leukemia Virus type-1 (HTLV-1) -associated myelopathy causes sufferers to experience changes in several aspects of their lives. Gaining a deeper understanding of these changes can help healthcare professionals improve care, enhance strategic decision-making, meet expectations, and manage patients effectively. However, there is no information about the experience and problems of patients with HTLV-1-associated myelopathy/tropical spastic paraparesis in Iran. Therefore, this study aimed to explain the lived experience of patients with HTLV-1-associated myelopathy/tropical spastic paraparesis.

Methods

This qualitative study used hermeneutic phenomenology in 2022 in Mashhad, Iran. Participants were selected using purposeful sampling. Data were collected through 21 semi-structured in-depth interviews with 20 eligible patients with HTLV-1-associated myelopathy/tropical spastic paraparesis. The data were analyzed in MAXQDA/2020 using the six stages proposed by Van Manen.

Results

The main concept of "Reduced self-sufficiency and social dignity" emerged from the narratives of the patients, which included three main categories "Disruption of desirable personal and social life", "reduced perception of role competencies", and "obligatory unpleasant lifestyle changes".

Conclusion

HTLV-1-associated myelopathy/tropical spastic paraparesis slowly makes patients feel insufficient and causes a sense of degradation in dignity. The disease can fundamentally change personal and social life. Thus, due to its incurability and progressiveness, palliative care should be provided to them to live with dignity.

Bacterial and Viral Infectious Disease of the Spine

Spinal infections are a diverse group of diseases affecting different compartments of the spine with variable clinical and imaging presentations. Diagnosis of spinal infections is based on a combination of clinical features, laboratory markers, and imaging studies. Imaging plays a pivotal role in the diagnosis and management of spinal infections. The characteristic imaging manifestations of bacterial and viral infections in the spine are discussed with key teaching points emphasized.

Non-cancerous complications in HTLV-1 carriers

INTRODUCTION

Human T-cell leukemia virus type 1 (HTLV-1) carriers may develop adult T-cell leukemia (ATL), or HTLV-1-associated myelopathy (HAM)/tropical spastic paraparesis (TSP). The evidence is limited regarding other diseases potentially associated with HTLV-1, such as HTLV-1-associated autoimmune diseases.

AREA COVERED

We summarized the available information on complications associated with HTLV-1 infection.

EXPERT OPINION

Previous studies showed that HTLV-1 carriers have an increased incidence of collagen diseases including Sjögren's syndrome, as well as dysthyroidism, diabetes mellitus, and atherosclerosis. Furthermore, cognitive deficits are observed in asymptomatic carriers and in symptomatic carriers who develop HAM/TSP. It is hypothesized that altered immunoregulation occurs as a result of persistent HTLV-1 infection. A systematic review and meta-analysis demonstrated that HTLV-1 infection itself has an adverse impact on overall survival. ATL alone cannot entirely explain the adverse impact of HTLV-1 infection on overall mortality, because the incidence is low, and therefore HTLV-1-associated diseases as a whole may contribute to the inferior clinical outcome. However, there are insufficient data to determine the causal relationship between HTLV-1 infection and each complication. While non-cancerous events linked to HTLV-1 infection are not fatal, they are likely to reduce quality of life. Large prospective studies should be conducted by international collaborators.

PCBP1 interacts with the HTLV-1 Tax oncoprotein to potentiate NF-κB activation

Human T-cell leukemia virus type 1 (HTLV-1) is the etiological agent of adult T-cell leukemia/lymphoma. The HTLV-1 Tax constitutively activates nuclear factor-κB (NF-κB) to promote the survival and transformation of HTLV-1-infected T cells. Despite extensive study of Tax, how Tax interacts with host factors to regulate NF-κB activation and HTLV-1-driven cell proliferation is not entirely clear. Here, we showed that overexpression of Poly (rC)-binding protein 1 (PCBP1) promoted Tax-mediated IκB kinase (IKK)-NF-κB signaling activation, whereas knockdown of PCBP1 attenuated Tax-dependent IKK-NF-κB activation. However, Tax activation of HTLV-1 long terminal repeat was unaffected by PCBP1. Furthermore, depletion of PCBP1 led to apoptosis and reduced proliferation of HTLV-1-transformed cells. Mechanistically, PCBP1 interacted and co-localized with Tax in the cytoplasm, and PCBP1 KH3 domain was indispensable for the interaction between PCBP1 and Tax. Moreover, PCBP1 facilitated the assembly of Tax/IKK complex. Collectively, our results demonstrated that PCBP1 may exert an essential effect in Tax/IKK complex combination and subsequent NF-κB activation, which provides a novel insight into the pathogenetic mechanisms of HTLV-1.

Beyond pathogens: the intriguing genetic legacy of endogenous retroviruses in host physiology

The notion that viruses played a crucial role in the evolution of life is not a new concept. However, more recent insights suggest that this perception might be even more expansive, highlighting the ongoing impact of viruses on host evolution. Endogenous retroviruses (ERVs) are considered genomic remnants of ancient viral infections acquired throughout vertebrate evolution. Their exogenous counterparts once infected the host's germline cells, eventually leading to the permanent endogenization of their respective proviruses. The success of ERV colonization is evident so that it constitutes 8% of the human genome. Emerging genomic studies indicate that endogenous retroviruses are not merely remnants of past infections but rather play a corollary role, despite not fully understood, in host genetic regulation. This review presents some evidence supporting the crucial role of endogenous retroviruses in regulating host genetics. We explore the involvement of human ERVs (HERVs) in key physiological processes, from their precise and orchestrated activities during cellular differentiation and pluripotency to their contributions to aging and cellular senescence. Additionally, we discuss the costs associated with hosting a substantial amount of preserved viral genetic material.

Repurposing integrase inhibitors against human T-lymphotropic virus type-1: a computational approach

Adult T-cell Lymphoma (ATL) is caused by the delta retrovirus family member known as Human T-cell Leukaemia Type I (HTLV-1). Due to the unavailability of any cure, the study gained motivation to identify some repurposed drugs against the virus. A quick and accurate method of screening licensed medications for finding a treatment for HTLV-1 is by cheminformatics drug repurposing in order to analyze a dataset of FDA approved integrase antivirals against HTLV-1 infection. To determine how the antiviral medications interacted with the important residues in the HTLV-1 integrase active regions, molecular docking modeling was used. The steady behavior of the ligands inside the active region was then confirmed by molecular dynamics for the probable receptor-drug complexes. Cabotegravir, Raltegravir and Elvitegravir had the best docking scores with the target, indicating that they can tightly bind to the HTLV-1 integrase. Moreover, MD simulation revealed that the Cabotegravir-HTLV-1, Raltegravir-HTLV-1 and Elvitegravir-HTLV-1 interactions were stable. It is obvious that more testing of these medicines in both clinical trials and experimental tests is necessary to demonstrate their efficacy against HTLV-1 infection.Communicated by Ramaswamy H. Sarma.

HTLV-1 induces an inflammatory CD4+CD8+ T cell population in HTLV-1-associated myelopathy

Human T cell leukemia virus type 1 (HTLV-1) is a retrovirus with preferential CD4+ T cell tropism that causes a range of conditions spanning from asymptomatic infection to adult T cell leukemia and HTLV-1-associated myelopathy (HAM), an inflammatory disease of the CNS. The mechanisms by which HTLV-1 induces HAM are poorly understood. By directly examining the ex vivo phenotype and function of T cells from asymptomatic carriers and patients with HAM, we show that patients with HAM have a higher frequency of CD4+CD8+ double-positive (DP) T cells, which are infected with HTLV-1 at higher rates than CD4+ T cells. Displaying both helper and cytotoxic phenotypes, these DP T cells are highly proinflammatory and contain high frequencies of HTLV-1-specific cells. Mechanistically, we demonstrate that DP T cells arise by direct HTLV-1 infection of CD4+ and CD8+ T cells. High levels of CD49d and CXCR3 expression suggest that DP T cells possess the ability to migrate to the CNS, and when cocultured with astrocytes, DP T cells induce proinflammatory astrocytes that express high levels of CXCL10, IFN-γ, and IL-6. These results demonstrate the potential of DP T cells to directly contribute to CNS pathology.

Measures for the Prevention of Mother-to-Child Human T-Cell Leukemia Virus Type 1 Transmission in Japan: The Burdens of HTLV-1-Infected Mothers

The main mode of mother-to-child transmission of the human T-cell leukemia virus (HTLV)-1 is through breastfeeding. Although the most reliable nutritional regimen to prevent HTLV-1 transmission is exclusive formula feeding, a recent meta-analysis revealed that short-term breastfeeding within 90 days does not increase the risk of infection. The protocol of the Japanese Health, Labor, and Welfare Science Research Group primarily recommended exclusive formula feeding for mothers who are positive for HTLV-1. However, there has been no quantitative research on the difficulties experienced by HTLV-1-positive mothers in carrying out these nutritional regimens, including the psychological burden. Therefore, this review was performed to clarify the burdens and difficulties encountered by mothers who are positive for HTLV-1; to this end, we analyzed the data registrants on the HTLV-1 career registration website "Carri-net" website. The data strongly suggest that it is not sufficient to simply recommend exclusive formula feeding or short-term breastfeeding as a means of preventing mother-to-child transmission; it is important for health care providers to understand that these nutritional regimens represent a major burden for pregnant women who are positive for HTLV-1 and to provide close support to ensure these women's health.

Mogamulizumab for Treatment of Human T-lymphotropic Virus Type 1-Associated Myelopathy/Tropical Spastic Paraparesis: A Single-Center US-based Series

BACKGROUND

Human T-lymphotropic virus type 1 (HTLV-1)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is a chronic neurological condition characterized by progressive myelopathic symptoms including spasticity, pain, weakness, and urinary symptoms, without proven treatments. Mogamulizumab (MOG) is a monoclonal antibody that binds CCR4 and leads to the clearance of HTLV-1-infected CCR4+ cells. A phase 1-2a study in Japan evaluated MOG for the treatment of HAM/TSP and reported decreases in HTLV-1 proviral load and neuroinflammatory markers, with clinical improvement in some participants.

METHODS

We administered MOG 0.1 mg/kg every 8 weeks to individuals with HAM/TSP as a compassionate and palliative treatment. Patients who received MOG had (1) a positive peripheral HTLV-1 antibody, (2) progressive myelopathic symptoms, and (3) a diagnosis of HAM/TSP.

RESULTS

Four female patients, ages 45-68, received MOG (range, 2-6 infusions) between 1 November 2019 and 30 November 2022. Two patients with <3 years of symptoms had milder disease, with Osame scores <4. The other 2, with >7 years of symptoms, had Osame scores >5. One patient, with 6 total treatments, received dose-reduced MOG after she developed a rash at the initial dose. The 2 patients with milder baseline disease reported symptomatic improvement and saw reductions in Osame and/or modified Ashworth scale scores during follow-up. The other 2 patients showed no improvement. All 4 developed rashes after receiving MOG-a treatment-limiting event in some cases.

CONCLUSIONS

Clinical trials are needed including diverse patient populations to assess the potential role of MOG for HAM/TSP. Our findings may help inform the development of these trials.

HTLV infection in blood donors from Mato Grosso do Sul state: a closer look at HTLV screening in Brazilian blood banks

Human T-lymphotropic virus (HTLV) infection has a worldwide distribution and currently, more than 2.5 million individuals have been infected in Brazil. The study aimed to investigate HTLV infection prevalence among blood donors in Mato Grosso do Sul, characterizing seroepidemiological profiles of HTLV-1/2 positive individuals and evaluating the blood bank's HTLV screening system. A cross-sectional survey was conducted among blood donors from Mato Grosso do Sul state (MS)-Central Brazil, between January to December 2021. The information was obtained from databases, samples from the collection of HEMOSUL, and active searching, with the completion of laboratory analyses. 35,278 blood donors were screened for anti-HTLV-1/2 by chemiluminescence immunoassay (CMIA). Among them, 78 were initially reactive for anti-HTLV-1/2 (2.21/1000). Out of 78, 67 returned to the blood center to collect a second sample for retesting with a second screening with CMIA. After confirmation, 8 samples were indeterminate, and 8 were confirmed as positive for HTLV antibodies. New tests were performed for the 8 positive samples, and 6 were confirmed as HTLV-1 infection (0.17/1,000), one as negative, and one as indeterminate. The present study describes the low prevalence of HTLV infection in blood donors from MS and contributes to the definition of the regional infection profile. The prevalence found in this study (0.017%-0.17/1000) shows to be a much lower value than the rates reported in other states in Brazil. We highlight the need for confirmatory testing for those seropositive donors in screening assays and the need for adequate counseling and patient management for those confirmed HTLV individuals.

Advances in the treatment of human T-cell lymphotropic virus type-I associated myelopathy

INTRODUCTION

Nearly 2-3% of those 10 to 20 million individuals infected with the Human T-cell lymphotropic virus type-1 (HTLV-1); are predisposed to developing HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). It is a neuro-inflammatory disease; differentiated from multiple sclerosis based on the presence of typical neurologic symptoms, confirmation of HTLV-1 infection, and other molecular biomarkers.

AREAS COVERED

A brief review of the epidemiology, host immune responses, and molecular pathogenesis of HAM/TSP is followed by detailed discussions about the host-related risk factors for developing HAM/TSP and success/failure stories of the attempted management strategies.

EXPERT OPINION

Currently, there is no effective treatment for HAM/TSP. Anti-retroviral therapy, peculiar cytokines (IFN-α), some anti-oxidants, and allograft bone marrow transplantation have been used for treating these patients with limited success. Under current conditions, asymptomatic carriers should be examined periodically by a neurologist for early signs of spinal cord injury. Then it is crucial to determine the progress rate to adapt the best management plan for each patient. Corticosteroid therapy is most beneficial in those with acute myelitis. However, slow-progressing patients are best managed using a combination of symptomatic and physical therapy. Additionally, preventive measures should be taken to decrease further spread of HTLV-1 infection.

[National Questionnaire Survey on the Actual Use and Content Evaluation of the human T-cell leukemia virus type I (HTLV-1) -associated Myelopathy (HAM) Practice Guidelines 2019]

It is not enough to just create medical practice guidelines; they are also required to be implemented into practice. Therefore, we surveyed specialists to determine the extent of the dissemination of the "HAM Practice Guidelines 2019," to quantify gaps, identify challenges, and understand needs in daily practice. The survey also revealed that the 25% of the specialists were unaware of the tests required for confirming human T-cell leukemia virus type I (HTLV-1) infection. Additionally, they had insufficient knowledge of the HTLV-1 infection. About 90.7% of the specialists agreed with the policy of determining treatment intensity based on disease activity. However, the implementation rate of cerebrospinal fluid marker measurement, which is useful for this assessment, was as low as 27%. Hence, it is important to use the findings of this study to further promote awareness about this issue.

Upregulation of Neuropilin-1 Inhibits HTLV-1 Infection

Infection with human T-cell leukemia virus type 1 (HTLV-1) can produce a spectrum of pathological effects ranging from inflammatory disorders to leukemia. In vivo, HTLV-1 predominantly infects CD4⁺ T-cells. Infectious spread within this population involves the transfer of HTLV-1 virus particles from infected cells to target cells only upon cell-to-cell contact. The viral protein, HBZ, was found to enhance HTLV-1 infection through transcriptional activation of ICAM1 and MYOF, two genes that facilitate viral infection. In this study, we found that HBZ upregulates the transcription of COL4A1, GEM, and NRP1. COL4A1 and GEM are genes involved in viral infection, while NRP1, which encodes neuropilin 1 (Nrp1), serves as an HTLV-1 receptor on target cells but has no reported function on HTLV-1-infected cells. With a focus on Nrp1, cumulative results from chromatin immunoprecipitation assays and analyses of HBZ mutants support a model in which HBZ upregulates NRP1 transcription by augmenting recruitment of Jun proteins to an enhancer downstream of the gene. Results from in vitro infection assays demonstrate that Nrp1 expressed on HTLV-1-infected cells inhibits viral infection. Nrp1 was found to be incorporated into HTLV-1 virions, and deletion of its ectodomain removed the inhibitory effect. These results suggest that inhibition of HTLV-1 infection by Nrp1 is caused by the ectodomain of Nrp1 extended from virus particles, which may inhibit the binding of virus particles to target cells. While HBZ has been found to enhance HTLV-1 infection using cell-based models, there may be certain circumstances in which activation of Nrp1 expression negatively impacts viral infection, which is discussed.

EZH1/2 dual inhibitors suppress HTLV-1-infected cell proliferation and hyperimmune response in HTLV-1-associated myelopathy

Background

Human T-cell leukemia virus type 1 (HTLV-1) causes HTLV-1-associated myelopathy (HAM), adult T-cell leukemia/lymphoma (ATL), HTLV-1-associated uveitis, and pulmonary diseases. Although both HAM and ATL show proliferation of infected cells, their pathogeneses are quite different. In particular, the pathogenesis of HAM is characterized by hyperimmune responses to HTLV-1-infected cells. Recently, we demonstrated the overexpression of histone methyltransferase EZH2 in ATL cells and the cytotoxic effects of EZH2 inhibitors and EZH1/2 dual inhibitors on these cells. However, these phenomena have never been studied in HAM. Furthermore, what effect these agents have on the hyperimmune response seen in HAM is completely unknown.

Methods

In this study, we investigated histone methyltransferase expression levels in infected cell populations (CD4⁺ and CD4⁺CCR4⁺ cells) from patients with HAM using microarray and RT-qPCR analyses. Next, using an assay system that utilizes the spontaneous proliferation characteristic of peripheral blood mononuclear cells derived from patients with HAM (HAM-PBMCs), we investigated the effects of EZH2 selective inhibitors (GSK126 and tazemetostat) and EZH1/2 dual inhibitors (OR-S1 and valemetostat, also known as DS-3201), particularly on cell proliferation rate, cytokine production, and HTLV-1 proviral load. We also examined the effect of EZH1/2 inhibitors on the proliferation of HTLV-1-infected cell lines (HCT-4 and HCT-5) derived from patients with HAM.

Results

We found elevated expression of EZH2 in CD4⁺ and CD4⁺CCR4⁺ cells from patients with HAM. EZH2 selective inhibitors and EZH1/2 inhibitors significantly inhibited spontaneous proliferation of HAM-PBMC in a concentration-dependent manner. The effect was greater with EZH1/2 inhibitors. EZH1/2 inhibitors also reduced the frequencies of Ki67⁺ CD4⁺ T cells and Ki67⁺ CD8⁺ T cells. Furthermore, they reduced HTLV-1 proviral loads and increased IL-10 levels in culture supernatants but did not alter IFN-γ and TNF-α levels. These agents also caused a concentration-dependent inhibition of the proliferation of HTLV-1-infected cell lines derived from patients with HAM and increased annexin-V(+)7-aminoactinomycin D(-) early apoptotic cells.

Conclusion

This study showed that EZH1/2 inhibitors suppress HTLV-1-infected cell proliferation through apoptosis and the hyperimmune response in HAM. This indicates that EZH1/2 inhibitors may be effective in treating HAM.

Imaging Spectrum of HTLV-1–Related Neurologic Disease

Purpose of Review

Human T-cell lymphotropic virus type 1 (HTLV-1)–associated myelopathy (HAM) is a well-recognized neurologic complication of HTLV-1. Beyond HAM, several other neurologic manifestations are increasingly recognized, including acute myelopathy, encephalopathy, and myositis. The clinical and imaging features of these presentations are less well understood and potentially underdiagnosed. In this study, we summarize the imaging features of HTLV-1–related neurologic disease, providing both a pictorial review and pooled series of the less well-recognized presentations.

Recent Findings

35 cases of acute/subacute HAM and 12 cases of HTLV-1–related encephalopathy were found. In subacute HAM, cervical and upper thoracic longitudinally extensive tranverse myelitis was noted, while in HTLV-1–related encephalopathy, confluent lesions in the frontoparietal white matter and along the corticospinal tracts were the most prevalent finding.

Summary

There are varied clinical and imaging presentations of HTLV-1–related neurologic disease. Recognition of these features aids early diagnosis where therapy may have the greatest benefit.

Putative role of HLA polymorphism among a Brazilian HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) population

Around ten million people are infected with HTLV-1 worldwide, and 1-4% develop HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP), characterized by an important degeneration of the spinal cord, which can lead to death. Distinct HLA alleles have been associated with either HAM/TSP susceptibility or protection. However, these HLA alleles set may change according to the population studied. Brazil is the second country in the number of HTLV-1-infected people and there are few reports addressing the HLA influence on HTLV-1 infection as well as on disease outcome. The objective of this study was to evaluate the influence of HLA alleles as a risk factor for HAM/TSP and the proviral load (PVL) levels, clinical progression, and death outcomes in an admixed Brazilian population. The HLA-A, -B, -C, and -DRB1 were genotyped in 375 unrelated HTLV-1-infected individuals divided into asymptomatic carriers (AC) (n = 165) and HAM/TSP (n = 210) in a longitudinal cohort from 8 to 22 years of follow-up. Because locus B deviated from Hardy-Weinberg Equilibrium for the study groups, the results represented for HLA-B alleles were inconclusive. The alleles HLA-A*68 and -C*07 were related to HAM/TSP risk in multivariate analysis. The alleles HLA-A*33, and -A*36 were associated with protection against disease progression in HAM/TSP patients, while -C*12, -C*14, and -DRB1*08 were associated with increased risk of death. In the AC group, the presence of, -C*06 and -DRB1*15 alleles influenced an increased PVL, in an adjusted linear regression model, while -A*30, -A*34, -C*06, -C*17 and -DRB1*09 alleles were associated with increased PVL in HAM/TSP group compared to HAM/TSP individuals not carrying these alleles. All these alleles were also related to increased PVL associated with clinical progression outcome. Increased PVL associated with the death outcome was linked to the presence of HLA-A*30. PVL has been associated with HLA, and several alleles were related in AC and HAM/TSP patients with or without interacting with clinical progression outcomes. Understanding the prognostic value of HLA in HAM/TSP pathogenesis can provide important biomarkers tools to improve clinical management and contribute to the discovery of new therapeutic interventions.

Human T-cell lymphotropic virus type 1 (HTLV-1) proposed vaccines: a systematic review of preclinical and clinical studies

BACKGROUND

Numerous vaccination research experiments have been conducted on non-primate hosts to prevent or control HTLV-1 infection. Therefore, reviewing recent advancements for status assessment and strategic planning of future preventative actions to reduce HTLV-1 infection and its consequences would be essential.

METHODS

MEDLINE, Scopus, Web of Science, and Clinicaltrials.gov were searched from each database's inception through March 27, 2022. All original articles focusing on developing an HTLV-1 vaccine candidate were included.

RESULTS

A total of 47 studies were included. They used a variety of approaches to develop the HTLV-1 vaccine, including DNA-based, dendritic-cell-based, peptide/protein-based, and recombinant vaccinia virus approaches. The majority of the research that was included utilized Tax, Glycoprotein (GP), GAG, POL, REX, and HBZ as their main peptides in order to develop the vaccine. The immunization used in dendritic cell-based investigations, which were more recently published, was accomplished by an activated CD-8 T-cell response. Although there hasn't been much attention lately on this form of the vaccine, the initial attempts to develop an HTLV-1 immunization depended on recombinant vaccinia virus, and the majority of results seem positive and effective for this type of vaccine. Few studies were conducted on humans. Most of the studies were experimental studies using animal models. Adenovirus, Cytomegalovirus (CMV), vaccinia, baculovirus, hepatitis B, measles, and pox were the most commonly used vectors.

CONCLUSIONS

This systematic review reported recent progression in the development of HTLV-1 vaccines to identify candidates with the most promising preventive and therapeutic effects.

Th17/IL-17 Axis in HTLV-1-Associated Myelopathy Tropical Spastic Paraparesis and Multiple Sclerosis: Novel Insights into the Immunity During HAMTSP

Human T lymphotropic virus-associated myelopathy/tropical spastic paraparesis (HTLV/TSP), also known as HTLV-associated myelopathy/tropical spastic paraparesis (HAM/TSP), and multiple sclerosis (MS) are chronic debilitating diseases of the central nervous system; although the etiology of which is different, similarities have been observed between these two demyelinating diseases, especially in clinical manifestation and immunopathogenesis. Exorbitant response of the immune system to the virus and neurons in CNS is the causative agent of HAM/TSP and MS, respectively. Helper T lymphocyte-17 cells (Th17s), a component of the immune system, which have a proven role in immunity and autoimmunity, mediate protection against bacterial/fungal infections. The role of these cells has been reviewed in several CNS diseases. A pivotal role for Th17s is presented in demyelination, even more axial than Th1s, during MS. The effect of Th17s is not well determined in HTLV-1-associated infections; however, the evidence that we have supplied in this review illustrates the attendance, also the role of Th17 cells during HAM/TSP. Furthermore, for better conception concerning the trace of these cells in HAM/TSP, a comparative characterization with MS, the resembling disease, has been applied here.

Clinical and Mechanistic Implications of R-Loops in Human Leukemias

Genetic mutations or environmental agents are major contributors to leukemia and are associated with genomic instability. R-loops are three-stranded nucleic acid structures consisting of an RNA-DNA hybrid and a non-template single-stranded DNA. These structures regulate various cellular processes, including transcription, replication, and DSB repair. However, unregulated R-loop formation can cause DNA damage and genomic instability, which are potential drivers of cancer including leukemia. In this review, we discuss the current understanding of aberrant R-loop formation and how it influences genomic instability and leukemia development. We also consider the possibility of R-loops as therapeutic targets for cancer treatment.

HAM/TSP Pathogenesis: The Transmigration Activity of HTLV-1-Infected T Cells into Tissues

Slowly progressive spastic paraparesis with bladder dysfunction, the main clinical feature of human T-cell leukemia virus-1 (HTLV-1)-associated myelopathy/tropical spastic paraparesis (HAM/TSP), is induced by chronic inflammation in the spinal cord, mainly the lower thoracic cord. A long-standing bystander mechanism, such as the destruction of surrounding tissues by inflammatory cytokines, etc., induced under the interaction between infiltrated HTLV-1-infected CD4⁺ T cells and HTLV-1-specific CD8⁺ cytotoxic T cells, has been considered implicated for the induction of chronic inflammation. As this bystander mechanism is triggered conceivably by the transmigration of HTLV-1-infected CD4⁺ T cells to the spinal cord, heightened transmigrating activity of HTLV-1-infected CD4⁺ T cells to the spinal cord might play a crucial role as the first responder in the development of HAM/TSP. This review evaluated the functions of HTLV-1-infected CD4⁺ T cells in HAM/TSP patients as the prerequisite for the acquisition of the activity such as adhesion molecule expression changes, small GTPases activation, and expression of mediators involved in basement membrane disruption. The findings suggest that HTLV-1-infected CD4⁺ T cells in HAM/TSP patients have enough potential to facilitate transmigration into the tissues. Future HAM/TSP research should clarify the molecular mechanisms leading to the establishment of HTLV-1-infected CD4⁺ T cells as the first responder in HAM/TSP patients. In addition, a regimen with an inhibitory activity against the transmigration of HTLV-1-infected CD4⁺ T cells into the spinal cord might be recommended as one of the therapeutic strategies against HAM/TSP patients.

Pentosan Polysulfate Affords Pleotropic Protection to Multiple Cells and Tissues

Pentosan polysulfate (PPS), a small semi-synthetic highly sulfated heparan sulfate (HS)-like molecule, shares many of the interactive properties of HS. The aim of this review was to outline the potential of PPS as an interventional therapeutic protective agent in physiological processes affecting pathological tissues. PPS is a multifunctional molecule with diverse therapeutic actions against many disease processes. PPS has been used for decades in the treatment of interstitial cystitis and painful bowel disease, it has tissue-protective properties as a protease inhibitor in cartilage, tendon and IVD, and it has been used as a cell-directive component in bioscaffolds in tissue engineering applications. PPS regulates complement activation, coagulation, fibrinolysis and thrombocytopenia, and it promotes the synthesis of hyaluronan. Nerve growth factor production in osteocytes is inhibited by PPS, reducing bone pain in osteoarthritis and rheumatoid arthritis (OA/RA). PPS also removes fatty compounds from lipid-engorged subchondral blood vessels in OA/RA cartilage, reducing joint pain. PPS regulates cytokine and inflammatory mediator production and is also an anti-tumor agent that promotes the proliferation and differentiation of mesenchymal stem cells and the development of progenitor cell lineages that have proven to be useful in strategies designed to effect repair of the degenerate intervertebral disc (IVD) and OA cartilage. PPS stimulates proteoglycan synthesis by chondrocytes in the presence or absence of interleukin (IL)-1, and stimulates hyaluronan production by synoviocytes. PPS is thus a multifunctional tissue-protective molecule of potential therapeutic application for a diverse range of disease processes.

Impaired flexibility in patients with tropical spastic paraparesis/HTLV-associated myelopathy: evaluation via pendulum fleximeter

BACKGROUND

 Flexibility is crucial to the harmonious execution of joint movements. While skeletal muscle dysfunction in patients with HTLV-1 can interfere with mobility, it is unclear whether these patients experience reduced flexibility.

OBJECTIVE

 To evaluate the differences in flexibility between HTLV-1-infected individuals with and without myelopathy compared with uninfected controls. We also investigated whether age, sex, body mass index (BMI), physical activity level, or lower back pain influence flexibility in HTLV-1-infected individuals.

METHODS

 The sample consisted of 56 adults, of which 15 did not have HTLV-1, 15 had HTLV-1 without myelopathy, and 26 had TSP/HAM. Their flexibility was assessed using the sit-and-reach test and a pendulum fleximeter.

RESULTS

 No differences in flexibility were observed between the groups with and without myelopathy and controls without HTLV-1 infection using the sit-and-reach test. The pendulum fleximeter results of individuals with TSP/HAM presented the lowest flexibility among the groups with respect to trunk flexion, hip flexion and extension, knee flexion, and ankle dorsiflexion, even after adjusting for age, sex, BMI, level of physical activity, and lower back pain using multiple linear regression models. Additionally, HTLV-1-infected individuals without myelopathy demonstrated reduced flexibility in movements: knee flexion, dorsiflexion, and ankle plantar flexion.

CONCLUSIONS

 Individuals with TSP/HAM demonstrated reduced flexibility in most of the movements evaluated by the pendulum fleximeter. Additionally, HTLV-1-infected individuals without myelopathy demonstrated reduced knee and ankle flexibility, potentially representing a marker of myelopathic development.

High Human T-Cell Leukemia Virus Type 1c Proviral Loads Are Associated With Diabetes and Chronic Kidney Disease: Results of a Cross-Sectional Community Survey in Central Australia

BACKGROUND

A link between chronic inflammation and several noncommunicable diseases (NCDs) has been established. Although chronic infection with the human T-cell leukemia virus type 1 (HTLV-1) is the recognized cause of several inflammatory diseases and these are associated with a high number of HTLV-1-infected cells in peripheral blood (proviral load [PVL]), possible interactions between PVL and NCDs have not been studied at a community level.

METHODS

Adult Aboriginal residents of 7 remote communities were invited to complete a health survey between 25 August 2014 and 30 June 2018. Blood was drawn for HTLV-1 serology and PVL, and relevant medical conditions were obtained from health records. Associations between HTLV-1 PVL and diabetes, chronic kidney disease (CKD), and coronary artery disease (CAD) were determined using logistic regression, adjusting for available confounders.

RESULTS

Among 510 participants (56% of the estimated adult resident population, 922), 197 (38.6%) were HTLV-1-infected. A high HTLV-1 PVL was associated with a 2-fold increase in the odds of diabetes and CKD (diabetes, adjusted odds ratio [aOR], 1.95; 95% confidence interval [CI], 1.06-3.61; P = .033 and CKD: aOR, 2.00; 95% CI, 1.03-3.8; P = .041). A nonsignificant association between high PVL and CAD (aOR, 7.08; 95% CI, 1.00-50.18; P = .05) was found for participants aged <50 years at the time of angiography.

CONCLUSIONS

In a community-based study in central Australia, people with HTLV-1 who had high HTLV-1 PVL were more likely to have diabetes and CKD. These findings have potential clinical implications.

Pathogenicity and virulence of human T lymphotropic virus type-1 (HTLV-1) in oncogenesis: adult T-cell leukemia/lymphoma (ATLL)

Adult T-cell leukemia/lymphoma (ATLL) is an aggressive malignancy of CD4⁺ T lymphocytes caused by human T lymphotropic virus type-1 (HTLV-1) infection. HTLV-1 was brought to the World Health Organization (WHO) and researchers to address its impact on global public health, oncogenicity, and deterioration of the host immune system toward autoimmunity. In a minority of the infected population (3-5%), it can induce inflammatory networks toward HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP), or hijacking the infected CD4⁺ T lymphocytes into T regulatory subpopulation, stimulating anti-inflammatory signaling networks, and prompting ATLL development. This review critically discusses the complex signaling networks in ATLL pathogenesis during virus-host interactions for better interpretation of oncogenicity and introduces the main candidates in the pathogenesis of ATLL. At least two viral factors, HTLV-1 trans-activator protein (TAX) and HTLV-1 basic leucine zipper factor (HBZ), are implicated in ATLL manifestation, interacting with host responses and deregulating cell signaling in favor of infected cell survival and virus dissemination. Such molecules can be used as potential novel biomarkers for ATLL prognosis or targets for therapy. Moreover, the challenging aspects of HTLV-1 oncogenesis introduced in this review could open new venues for further studies on acute leukemia pathogenesis. These features can aid in the discovery of effective immunotherapies when reversing the gene expression profile toward appropriate immune responses gradually becomes attainable.

HTLV-I associated bronchioloalveolar disorder (HABA): disease concept and differential diagnosis of an unsolved disease entity

INTRODUCTION

Human T-cell leukemia virus type 1 (HTLV-I) associated bronchioloalveolar disorder (HABA) is a chronic and progressive bronchiolar/alveolar disorder related to HTLV-1 infection. Clinical knowledge and guidance are lacking for the diagnosis and management of this condition.

AREAS COVERED

This work aimed to review the latest information and challenges regarding HABA diagnosis and treatment.

EXPERT OPINION

HABA is an immune-mediated state induced by HTLV-1. For diagnosis of HABA, other infectious diseases and pulmonary infiltration of adult T-cell leukemia should be excluded by investigations such as computed tomography (CT), transbronchial biopsy, and bronchoalveolar lavage fluid (BALF) analysis. Typical CT findings in HABA include diffuse panbronchiolitis-like or bronchiectasis patterns, whereas cases with other abnormalities, including interstitial pneumonia, have also been reported. A high rate of polyclonal CD4+ and CD25+ lymphocytes is detected in BALF of patients with HABA, reflecting the infiltration of HTLV-1 infected T-cells in the lung. Current treatment options are not HABA specific, and include corticosteroids, macrolide antibiotics, and pirfenidone. Mitigation of the adverse effects of HTLV-1 infection requires the establishment of diagnostic criteria for the disease, screening programs for HABA in HTLV-1 infected individuals, and the development of effective disease treatment strategies.

Profile of neurological disorders in a tertiary center of education in orthopedics

BACKGROUND

Neurological conditions can cause secondary orthopedic disorders and can result from orthopedic surgical procedures. In addition, misdiagnosis and overtreatment involve both specialties. Epidemiological studies of neurological patients in tertiary units are often performed in emergency departments of general hospitals or rehabilitation centers.

OBJECTIVE

Describe the clinical and epidemiologic profile of neurological disorders in a Brazilian federal tertiary center and education hospital in orthopedics in Rio de Janeiro.

METHODS

We performed a retrospective study of the medical records of patients attended by neurology specialists of the internal medicine's department of the National Institute of Traumatology and Orthopedics from February 2014 to March 2020.

RESULTS

We reviewed neurological referrals in the medical records of 1,349 patients in the period. The mean age of patients was 49.67 years (standard deviation [SD] ± 18.99). There was a predominance of females, corresponding to 751 (55.7%) patients. Regarding ethnicity, 684 (50.7%) participants were white, 550 (40.8%) non-white, and 115 (8.5%) non-classified. Peripheral neuropathies (34.1%), osteoarticular diseases (10%), epilepsy (8.3%), developmental disorders (7.9%), and neuromuscular diseases (7.3%) were the 5 groups with the largest numbers of cases.

CONCLUSION

The sample consisted mostly of females and white individuals, and approximately one third of the cases were of peripheral neuropathies. Epidemiological studies in neurology from tertiary centers of another medical specialty can improve the professional development of both specialties. This interdisciplinary approach can also optimize resources, help avoid misdiagnosis, and reduce disability.

Efficacy of l-Arginine treatment in patients with HTLV-1-associated neurological disease

OBJECTIVE

HTLV-1 infection causes HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP), resulting in loss of motor function. In this Phase 2 trial, we assessed the efficacy and safety of l-arginine in patients with HAM/TSP.

METHODS

This open-label, single-arm, Phase 2 study enrolled patients diagnosed with HAM/TSP. Patients received l-arginine at a dose of 20 g orally for 1 week and were followed-up for 3 weeks. The primary endpoint was change in walking speed in the 10-m walk test (10MWT). The main secondary endpoints were change in Timed Up and Go Test (TUGT) time, improvement in inflammatory markers in cerebrospinal fluid (CSF), safety, and tolerability.

RESULTS

The study enrolled 20 patients (13 [65%] female) with a mean age of 67.8 years (95% CI 62.3 to 73.3). Although the primary endpoint, the changes in 10MWT time between baseline (Day 0) and Day 7, did not reach statistical significance (mean percent change in time -3.5%, 95% CI -10.8% to 3.7%; P = 0.32), a significant improvement was detected between baseline and Day 14 (-9.4%, 95% CI -16.6% to -2.2%; P = 0.01). Significant improvements were also observed in selected secondary endpoints, including in TUGT time (-9.1%, 95% CI -15.5% to -2.7%; P < 0.01), and in neopterin concentration in CSF (-2.1 pmol/mL, 95% CI -3.8 to -0.5; P = 0.01). Adverse events were infrequent, mild, and resolved rapidly.

INTERPRETATION

l-arginine therapy improved motor function and decreased CSF inflammatory markers. l-arginine thus represents a promising therapeutic option for patients with HAM/TSP.

TRIAL REGISTRATION NUMBER

UMIN000023854.

Systemic cytokines and GlycA discriminate disease status and predict corticosteroid response in HTLV-1-associated neuroinflammation

BACKGROUND

HTLV-1-Associated Myelopathy/Tropical Spastic Paraparesis (HAM/TSP) is an incapacitating neuroinflammatory disorder for which no disease-modifying therapy is available, but corticosteroids provide some clinical benefit. Although HAM/TSP pathogenesis is not fully elucidated, older age, female sex and higher proviral load are established risk factors. We investigated systemic cytokines and a novel chronic inflammatory marker, GlycA, as possible biomarkers of immunopathogenesis and therapeutic response in HAM/TSP, and examined their interaction with established risk factors.

PATIENTS AND METHODS

We recruited 110 People living with HTLV-1 (PLHTLV-1, 67 asymptomatic individuals and 43 HAM/TSP patients) with a total of 946 person-years of clinical follow-up. Plasma cytokine levels (IL-2, IL-4, IL-6, IL-10, IL-17A, IFN-γ, TNF) and GlycA were quantified by Cytometric Bead Array and ¹NMR, respectively. Cytokine signaling and prednisolone response were validated in an independent cohort by nCounter digital transcriptomics. We used multivariable regression, machine learning algorithms and Bayesian network learning for biomarker identification.

RESULTS

We found that systemic IL-6 was positively correlated with both age (r = 0.50, p < 0.001) and GlycA (r = 0.45, p = 0.00049) in asymptomatics, revealing an 'inflammaging" signature which was absent in HAM/TSP. GlycA levels were higher in women (p = 0.0069), but cytokine levels did not differ between the sexes. IFN-γ (p = 0.007) and IL-17A (p = 0.0001) levels were increased in untreated HAM/TSP Multivariable logistic regression identified IL-17A and proviral load as independent determinants of clinical status, resulting in modest accuracy of predicting HAM/TSP status (64.1%), while a machine learning-derived decision tree classified HAM/TSP patients with 90.7% accuracy. Pre-treatment GlycA and TNF levels significantly predicted clinical worsening (measured by Osame Motor Disability Scale), independent of proviral load. In addition, a poor prednisolone response was significantly correlated with higher post-treatment IFN-γ levels. Likewise, a transcriptomic IFN signaling score, significantly correlated with previously proposed HAM/TSP biomarkers (CASP5/CXCL10/FCGR1A/STAT1), was efficiently blunted by in vitro prednisolone treatment of PBMC from PLHTLV-1 and incident HAM/TSP.

CONCLUSIONS

An age-related increase in systemic IL-6/GlycA levels reveals inflammaging in PLHTLV-1, in the absence of neurological disease. IFN-γ and IL-17A are biomarkers of untreated HAM/TSP, while pre-treatment GlycA and TNF predict therapeutic response to prednisolone pulse therapy, paving the way for a precision medicine approach in HAM/TSP.

A newly identified interaction between nucleolar NPM1/B23 and the HTLV-I basic leucine zipper factor in HTLV-1 infected cells

Human T-cell leukemia virus type 1 is the causative agent of HTLV-1-associated myelopathy/tropical spastic paraparesis and adult T-cell leukemia-lymphoma (ATL). The HTLV-1 basic leucine zipper factor (HBZ) has been associated to the cancer-inducing properties of this virus, although the exact mechanism is unknown. In this study, we identified nucleophosmin (NPM1/B23) as a new interaction partner of HBZ. We show that sHBZ and the less abundant uHBZ isoform interact with nucleolar NPM1/B23 in infected cells and HTLV-1 positive patient cells, unlike equivalent antisense proteins of related non-leukemogenic HTLV-2, -3 and-4 viruses. We further demonstrate that sHBZ association to NPM1/B23 is sensitive to RNase. Interestingly, sHBZ was shown to interact with its own RNA. Through siRNA and overexpression experiments, we further provide evidence that NPM1/B23 acts negatively on viral gene expression with potential impact on cell transformation. Our results hence provide a new insight over HBZ-binding partners in relation to cellular localization and potential function on cell proliferation and should lead to a better understanding of the link between HBZ and ATL development.

HTLV infection in Brazil's second-largest indigenous reserve

Human T-lymphotropic viruses 1 and 2 (HTLV-1/2) have a worldwide distribution. HTLV-1 has been associated with several diseases, including an aggressive malignant disease known as adult T-cell leukemia/lymphoma and a chronic inflammatory neurological disease called HTLV-1-associated myelopathy, while HTLV-2 has not been definitively associated with diseases. HTLV-2 is most prevalent in specific groups such as injecting drug users and the indigenous population. In Brazil, most studies about HTLV in indigenous are carried out in indigenous communities from the north of the country. Mato Grosso do Sul (MS), Central Brazil, has the second-largest indigenous population in Brazil. However, there is no available data about HTLV infection in this group. We conducted the first investigation of HTLV-1/2 infection prevalence in the indigenous population from Jaguapiru and Bororó villages in Dourados City, MS, to provide the prevalence and molecular characterization of HTLV. For that, a total of 1875 indigenous participated in the study. All the serum samples were screened by an enzyme-linked immunosorbent assay commercial kit for the presence of anti-HTLV-1/2 antibodies. Positive samples were confirmed by HTLV-1/2 Western Blot assay. The HTLV-1 5’LTR region was detected by nested PCR amplification and sequenced by Sanger. Most of the study population declared belonging to Guarani-Kaiowá ethnicity (69.18%), 872 (46.51%), and 1003 (53.49%) were from Jaguapiru and Bororó villages, respectively. The median age of participants was 31 years, and 74.24% were females. Two individuals were detected with HTLV-1 (0.1%; CI 95% 0.1–0.2). The phylogenetic analysis revealed that isolates belong to the Cosmopolitan subtype and the Transcontinental subgroup (HTLV-1aA). The low HTLV-1 prevalence found in this study is similar to that observed among blood donors, and pregnant populations from Mato Grosso do Sul. The absence of HTLV-2 infection among these Brazilian indigenous communities would suggest a distinct behavior pattern from other indigenous populations in Brazil.

Lessons from the Cerebrospinal Fluid Analysis of HTLV-1-Infected Individuals: Biomarkers of Inflammation for HAM/TSP Development

HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is a neurodegenerative disease that leads to motor impairment due to a chronic inflammatory process in the central nervous system (CNS). However, the HAM/TSP pathogenesis is not completely clear, and biomarkers to define the disease prognosis are still necessary. Thus, we aimed to identify biomarkers for HAM/TSP and potential mechanisms involved in disease development. To that end, the concentrations of VILIP-1, BDNF, VEGF, β-NGF, TGF-β1, fractalkine/CX3CL1, IL-6, IL-18, and TNF-α, and the soluble forms of TREM-1, TREM-2, and RAGE, were assessed using a multiplex bead-based immunoassay in paired cerebrospinal fluid (CSF) and serum samples from HAM/TSP patients (n = 20), asymptomatic HTLV-1 carriers (AC) (n = 13), and HTLV-1-seronegative individuals (n = 9), with the results analyzed according to the speed of HAM/TSP progression. HAM/TSP patients had elevated fractalkine in the serum but not in the CSF, particularly those with low neuroinflammatory activity (CSF/serum ratio of neopterin <1 and of CXCL10 < 2). HAM/TSP patients with normal CSF levels of neurofilament light chain (NfL) showed elevated β-NGF in serum, and serum BDNF levels were increased in HTLV-1-infected individuals, particularly in HTLV-1 AC. Both HTLV-1 AC and HAM/TSP patients had lower TGF-β1 levels in CSF compared to uninfected individuals, and HAM/TSP patients with active CNS inflammation showed higher CSF levels of IL-18, which correlated with markers of inflammation, neuronal death, and blood−brain-barrier permeability. Although none of the factors evaluated were associated with the speed of HAM/TSP progression, reduced TGF-β1 levels in CSF suggest that suppressive responses to control subclinical and/or active neurodegeneration are impaired, while increased CSF IL-18 indicates the involvement of inflammasome-mediated mechanisms in HAM/TSP development.

Late presentation of HTLV-1 infection in Spain reflects suboptimal testing strategies

BACKGROUND

. Although only 10% of persons infected with HTLV-1 may develop virus-associated illnesses lifelong, missing the earlier diagnosis of asymptomatic carriers frequently leads to late presentation.

METHODS

. A nationwide HTLV-1 register was created in Spain in 1989. We examined the main demographics and clinical features at the time of first diagnosis during more than three decades.

RESULTS

. A total of 428 individuals infected with HTLV-1 had been reported in Spain until the end of 2021. Up to 96 (22%) individuals presented clinically with HTLV-1-associated conditions, including subacute myelopathy (57%), T-cell lymphoma (34%), or Strongyloides stercoralis infestation (8%). Since 2008, HTLV-1 diagnosis has been made either at blood banks (44%) or at clinics (56%). Native Spaniards and Sub-Saharan Africans are overepresented among patients presenting with HTLV-1-associated illnesses suggesting that poor epidemiological and/or clinical suspicion leading to late presentation are more frequent in them compared to LATAM carriers (31.7% vs 20.4%, respectively; p=0.015).

CONCLUSION

. HTLV-1 infection in Spain is frequently diagnosed in patients presenting with characteristic illnesses. Whereas screening in blood banks mostly identifies asymptomatic LATAM carriers, a disproportionately high number of Spaniards and Africans are diagnosed too late, at the time of clinical manifestations. Expanding testing to all pregnant women and clinics for sexually transmitted infections could help to unveil HTLV-1 asymptomatic carriers.

Probable HTLV-I/II Tropical Spastic Paraparesis Patient from Ethiopia: A Case Report

Background

Available data on the burden of Human T-cell lymphotropic virus type I/II infection for eastern Africa, limited to Ethiopia, Mozambique, and Rwanda, show prevalence lower than elsewhere in Africa (0% – 1.8%). Even if Tropical Spastic Paraparesis occurs in an endemic form in Ethiopia, its seroprevalence is low. Over a lifetime, it is estimated that 1–2% of Human T-cell lymphotropic virus type I/ II -infected individuals will develop progressive and disabling inflammatory clinical manifestations. We are reporting this case since it signifies the existence of seropositive Tropical Spastic Paraparesis in our setting and the need to properly diagnose this condition.

Case Presentation

We are reporting a 45 years old female patient from Addis Ababa, Ethiopia, who presented with progressive weakness of the lower limbs and urinary urge incontinence of five years duration. Serology for Human T-cell lymphotropic virus type I/ II antibody was positive. She was diagnosed to have probable tropical spastic paraparesis after fulfilling World Health Organization diagnostic criteria for tropical spastic paraparesis with the level of ascertainment. Symptoms showed transient improvements after providing five days of Methylprednisolone followed by low doses of corticosteroids and Azathioprine. The patient is now significantly disabled and wheelchair-bound.

Conclusions

The patient described here signifies a probable Human T-cell lymphotropic virus type I/ II - associated myelopathy/tropical spastic paraparesis in Ethiopian women. This case highlights the existence of Human T-cell lymphotropic virus type I/II - associated myelopathy/ tropical spastic paraparesis within our setting and the need to properly diagnose this condition.

Amyotrophic lateral sclerosis mimics

Amyotrophic lateral sclerosis (ALS) is the most common adult-onset motor neuron disorder characterized by progressive degeneration of cortical, bulbar, and spinal motor neurons. When a patient presents with a progressive upper and/or lower motor syndrome, clinicians must pay particular attention to any atypical features in the history and/or clinical examination suggesting an alternate diagnosis, as up to 10% percent of patients initially diagnosed with ALS have a mimic of ALS. ALS is a clinical diagnosis and requires the exclusion of other disorders that may have similar presentations but a more favorable prognosis or an effective therapy. Because there is currently no specific diagnostic biomarker that is sensitive or specific for ALS, understanding the spectrum of clinical presentations of ALS and its mimics is paramount. While true mimics of ALS are rare, the clinician must correctly identify these disorders to avoid the misdiagnosis of ALS and to initiate effective treatment where available.

Clinical and Public Health Implications of Human T-Lymphotropic Virus Type 1 Infection

Human T-lymphotropic virus type 1 (HTLV-1) is estimated to affect 5 to 10 million people globally and can cause severe and potentially fatal disease, including adult T-cell leukemia/lymphoma (ATL) and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). The burden of HTLV-1 infection appears to be geographically concentrated, with high prevalence in discrete regions and populations. While most high-income countries have introduced HTLV-1 screening of blood donations, few other public health measures have been implemented to prevent infection or its consequences. Recent advocacy from concerned researchers, clinicians, and community members has emphasized the potential for improved prevention and management of HTLV-1 infection. Despite all that has been learned in the 4 decades following the discovery of HTLV-1, gaps in knowledge across clinical and public health aspects persist, impeding optimal control and prevention, as well as the development of policies and guidelines. Awareness of HTLV-1 among health care providers, communities, and affected individuals remains limited, even in countries of endemicity. This review provides a comprehensive overview on HTLV-1 epidemiology and on clinical and public health and highlights key areas for further research and collaboration to advance the health of people with and at risk of HTLV-1 infection.

Health-Related Quality of Life Evaluation Using the Short Form-36 in Patients With Human T-Lymphotropic Virus Type 1-Associated Myelopathy

Background

Human T-lymphotropic virus type 1 (HTLV-1)-associated myelopathy (HAM) is a neuroinflammatory disease, causing various neurological symptoms, including motor, sensory, and bladder and bowel dysfunctions. This study was designed to reveal the impact of HAM and related symptoms on health-related quality of life (HRQoL).

Methods

We analyzed the Short Form-36 (SF-36) and clinical data of 538 patients with HAM registered in the HAM-net, a nationwide patient registry for HAM in Japan. HRQoL was evaluated using the SF-6D (a health state utility value calculated from the SF-36) and eight SF-36 subscales. A general liner model was used to estimate the impact of major HAM-related symptoms, including gait dysfunction, sensory disturbance in the legs (pain and numbness), urinary dysfunction, and constipation, on the SF-6D and SF-36 subscale scores.

Results

The mean age and disease duration were 62.0 and 16.5 years, respectively. Of the patients, 73.2% needed walking aid; 42.7 and 67.1% had leg pain and numbness, respectively; 92.1% had urinary dysfunction; and 77.9% had constipation. The mean SF-6D score was 0.565, which was significantly lower than the national average (0.674 in the 60–69 years age group; p < 0.001), exceeding the minimal important difference (0.05–0.1). All the major symptoms were significantly associated with a decrease in the SF-6D score. The SF-36 subscale scores were significantly lower than the national standard of 50 (p ≤ 0.001), except for mental health (MH). Gait dysfunction was associated with lower scores in physical functioning (PF), limitations on role functioning because of physical health, bodily pain, general health perception (GH), vitality (VT), and social functioning; however, no association was observed between gait dysfunction and limitations on role functioning because of emotional problems and MH. Meanwhile, sensory disturbance in the legs was associated with a decrease in scores in all subscales. Urinary dysfunction was associated with worse PF, GH, VT, and MH. Constipation was associated only with PF.

Conclusion

HRQoL of patients with HAM was worse than that of the general population and was associated with all major symptoms. Thus, patients should be comprehensively managed to achieve better HRQoL.

Reflections on Some of the Exceptional Features of HTLV-1 and HTLV-1 Research: A Perspective

The report is not a review or a summary. In a manner, it is a perspective but an unusual one. It looks back to the years my colleagues and I (RG) began preparing for human retroviruses (beginning in 1970), how they evolved, and attempts to bring to light or simply to emphasize many exceptional characteristics of a retrovirus known as HTLV-1 and some fortuitous coincidences, with emphasis on the needs of the field. These events cover over one half a century. We have had many reviews on HTLV-1 disease, epidemiology, and basic aspects of its replication, genome, gene functions, structure, and pathogenesis, though continued updates are needed. However, some of its truly exceptional features have not been highlighted, or at least not in a comprehensive manner. This article attempts to do so.

Cytolytic Recombinant Vesicular Stomatitis Viruses Expressing STLV-1 Receptor Specifically Eliminate STLV-1 Env-Expressing Cells in an HTLV-1 Surrogate Model In Vitro

Human T-cell leukemia virus type 1 (HTLV-1) causes serious and intractable diseases in some carriers after infection. The elimination of infected cells is considered important to prevent this onset, but there are currently no means by which to accomplish this. We previously developed “virotherapy”, a therapeutic method that targets and kills HTLV-1-infected cells using a cytolytic recombinant vesicular stomatitis virus (rVSV). Infection with rVSV expressing an HTLV-1 primary receptor elicits therapeutic effects on HTLV-1-infected envelope protein (Env)-expressing cells in vitro and in vivo. Simian T-cell leukemia virus type 1 (STLV-1) is closely related genetically to HTLV-1, and STLV-1-infected Japanese macaques (JMs) are considered a useful HTLV-1 surrogate, non-human primate model in vivo. Here, we performed an in vitro drug evaluation of rVSVs against STLV-1 as a preclinical study. We generated novel rVSVs encoding the STLV-1 primary receptor, simian glucose transporter 1 (JM GLUT1), with or without an AcGFP reporter gene. Our data demonstrate that these rVSVs specifically and efficiently infected/eliminated the STLV-1 Env-expressing cells in vitro. These results indicate that rVSVs carrying the STLV-1 receptor could be an excellent candidate for unique anti-STLV-1 virotherapy; therefore, such antivirals can now be applied to STLV-1-infected JMs to determine their therapeutic usefulness in vivo.

Clonal Selection and Evolution of HTLV-1-Infected Cells Driven by Genetic and Epigenetic Alteration

T cells infected with human T-cell leukemia virus type 1 (HTLV-1) acquire various abnormalities during a long latent period and transform into highly malignant adult T-cell leukemia-lymphoma (ATL) cells. This can be described as “clonal evolution”, in which a single clone evolves into ATL cells after overcoming various selective pressures in the body of the infected individuals. Many studies have shown that the genome and epigenome contain a variety of abnormalities, which are reflected in gene expression patterns and define the characteristics of the disease. The latest research findings suggest that epigenomic disorders are thought to begin forming early in infection and evolve into ATL through further changes and accentuation as they progress. Genomic abnormalities profoundly affect clonal dominance and tumor cell characteristics in later events. ATL harbors both genomic and epigenomic abnormalities, and an accurate understanding of these can be expected to provide therapeutic opportunities.

Case Series: Pediatric Human T-Lymphotropic Virus Type 1 and Its Clinical Expression

Purpose

Human T-lymphotropic Virus type 1 (HTLV-1) was the first retrovirus to be identified and associated with oncogenic activity. It is estimated that approximately 10–20 million people in the world are infected with it. The clinical manifestations most commonly associated with HTLV-1 infection include T-cell leukemia/lymphoma and myelopathy associated to HTLV-1 infection. The purpose of this study is to describe clinical and demographic characteristics in pediatric patients with HTLV-1 infection.

Methodology and Patients

Ambispective case series analysis, with collection of medical records and subsequent description of demographic data (sex, origin, age) and clinical characteristics in 16 patients with HTLV-1 infection were collected. Twelve of these patients were part of an initially reported cohort and four were recruited later in the study. The patients were collected between January 2017 and July 2021 in a pediatric institution in Cali, in a reference hospital in the southwest region of Colombia.

Results

Thirteen of a total of sixteen patients came from the Colombian Pacific coast, where nine were with significant nutritional deficiencies. Seven showed dermatological compromise. Eight patients presented images compatible with inflammation and chronic lung injury, and six of the eight patients were with opportunistic infections. Coinfection with other microorganisms was also observed where one case presented with meningeal tuberculosis, another patient presented with simultaneous infections, namely, malaria, leptospirosis and toxoplasmosis, and a third patient presented intestinal parasitosis and soft tissue infection by Streptococcus pyogenes. Three patients had concomitant autoimmune diseases and a fourth patient was highly suspicious of having polymyositis.

Conclusions

The different clinical findings with simultaneous HTLV-1 infection broaden the panorama to suspect infection by this virus. More studies are required to achieve a direct association between structural lung disease, autoimmune diseases, immunodeficiency and HTLV-1 infection. This study aims to raise interest and awareness of an ancient but neglected disease.

Efficacy of Corticosteroid Therapy for HTLV-1-Associated Myelopathy: A Randomized Controlled Trial (HAMLET-P)

Corticosteroids are most commonly used to treat HTLV-1-associated myelopathy (HAM); however, their clinical efficacy has not been tested in randomized clinical trials. This randomized controlled trial included 8 and 30 HAM patients with rapidly and slowly progressing walking disabilities, respectively. Rapid progressors were assigned (1:1) to receive or not receive a 3-day course of intravenous methylprednisolone in addition to oral prednisolone therapy. Meanwhile, slow progressors were assigned (1:1) to receive oral prednisolone or placebo. The primary outcomes were a composite of ≥1-grade improvement in the Osame Motor Disability Score or ≥30% improvement in the 10 m walking time (10 mWT) at week 2 for rapid progressors and changes from baseline in 10 mWT at week 24 for slow progressors. In the rapid progressor trial, all four patients with but only one of four without intravenous methylprednisolone achieved the primary outcome (p = 0.14). In the slow progressor trial, the median changes in 10 mWT were −13.8% (95% CI: −20.1–−7.1; p < 0.001) and −6.0% (95% CI: −12.8–1.3; p = 0.10) with prednisolone and placebo, respectively (p for between-group difference = 0.12). Whereas statistical significance was not reached for the primary endpoints, the overall data indicated the benefit of corticosteroid therapy. (Registration number: UMIN000023798, UMIN000024085)

A Refractory, Infected Lung Bulla and an Abscess Treated Using Percutaneous Drainage in a Patient With Human T-Lymphotropic Virus Type 1-Associated Myelopathy

We present a case of a 54-year-old Japanese woman with established human T-lymphotropic virus type 1 (HTLV-1)-associated myelopathy who developed a refractory infected lung bulla and lung abscess caused by Pseudomonas aeruginosa, Methicillin-resistant Staphylococcus aureus, and Aspergillusspecies. Since antibiotic treatment alone failed to resolve the infection, percutaneous drainage of the infected bulla was performed. Although a prolonged treatment period was necessary, the infected lung bulla and the lung abscess were eventually resolved. During her illness, the patient also developed arthritis, possibly related to the HTLV-1 infection. Thus, persons infected with HTLV-1 can develop refractory infections, myelopathy, and arthritis. Percutaneous drainage is an option to treat refractory infected lung bullae.

Identification of dysregulated pathways underlying HTLV-1-associated myelopathy/tropical spastic paraparesis through co-expression network analysis

Human T cell lymphotropic virus-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is a pathogen-caused disease which is associated with the progressive neurological disorder. HAM/TSP affects the expression level of several proteins and dysregulates some biological pathways. To identify the interaction patterns among expressed genes in HAM/TSP patients, weighted gene co-expression network analysis (WGCNA) was applied. Three microarray datasets regarding HAM/TSP were merged, and the co-expression network was constructed among genes. A total of 38 modules were identified. Three preserved modules in HAM/TSP in comparison to the healthy subjects which also had the most connected proteins and enriched in the biological pathways were selected. These modules were enriched in pathways related to immune systems, cell cycle, viral infection, and neuronal systems. Moreover, the involvement of novel immunological-related proteins including C1QB, GBP5, PSME1, SERPING1, and UBE2C; neurological-related proteins including TUBA4A, TUBB8, and TP63; and also proteins including TRPC6, PRKG2, OPRD1, PRKACA, and TUBB4A involved in the cGMP-PKG signaling pathway, thyroid hormone synthesis, and recruitment of mitotic centrosome proteins and complexes were found. Therefore, tracing these proteins and the identified modules can shed light on the pathogenesis mechanism of HAM/TSP and help to find potential therapeutic targets. However, further experimental validation should be performed to confirm the proposed functional players.