HTLV-1 Associated Neurological Complex. What is Hidden below the Water?

HTLV-1-associated myelopathy in Spain

BACKGROUND

HTLV-1 infection is a neglected disease. Over 10 million people are infected worldwide, with hot spots of high endemicity across all continents. Roughly 5% of HTLV-1 carriers develop HTLV-1-associated myelopathy (HAM), a progressive subacute neurological disabling disease.

METHODS

We report the main features of patients diagnosed with HAM up to date in Spain, a non-endemic country with a relatively high migrant flow from Latin America and Equatorial Africa, where HTLV-1 is endemic.

RESULTS

A total of 451 cases of HTLV-1 had been recorded in Spain until the end of year 2022. HAM had been diagnosed in 58 (12.9%). The current incidence is of 2-3 new cases per year. Women represent 76%. Mean age at diagnosis is 49 years-old. Nearly 60% are Latin Americans. Although sexual transmission is the most likely route of HTLV-1 acquisition, up to 6 individuals had been infected following solid organ transplantation. Rapid onset myelopathy developed in all but one of these transplant recipients from three HTLV-1-positive donors. HTLV-1 subtype 1a transcontinental was the only variant recognized in HAM patients. HTLV-1 proviral load was significantly greater in HAM patients than in asymptomatic HTLV-1 carriers (677 vs 104 HTLV-1 DNA copies/104 PBMC; p = 0.012). Symptom relief medications and physiotherapy have been the only treatment providing some benefit to HAM patients. Neither significant clinical nor virological efficacy was noticed using antiretrovirals in at least 9 HAM patients. Two thirds of HAM patients ended up in a wheelchair and with urinary/fecal sphincter incontinence.

CONCLUSION

HAM is the most frequent clinical manifestation of HTLV-1 infection in Spain, a non-endemic country. Middle aged women migrants from Latin America are the most frequently affected. Two thirds end up in a wheelchair despite using antiretroviral therapy.

Providing a Nursing Care Plan as a Requirement for Secondary Prevention for People Living With HTLV-1

Introduction

The absence of nursing care plans aimed at people living with HTLV-1 (PLHTLV) led us to develop and test a proposed nursing care plan based on the evaluation of 55 PLHTLV to outline interventions according to the clinical stage.

Methods

After interviews with symptomatic patients, nursing diagnoses were made using the NANDA International Nursing Diagnoses (The International Nursing Knowledge Association). Subsequently, interventions were selected through the Classification of Nursing Interventions (NIC), and expected results were selected through the Classification of Nursing Outcomes (NOC).

Results

The actual diagnoses included (ii) chronic pain, (iii) impaired urinary elimination, and (iv) sexual dysfunction; the health promotion diagnosis was (i) risk-prone health behavior; and the risk diagnoses were (i) risk of feeling powerless and (ii) risk of falls in adults. Nursing care must prevent the lack of adherence to monitoring, establish goals and promote family involvement. A safe home environment requires intervention for fall prevention. Full support in understanding pharmacological and non-pharmacological therapies for chronic pain is needed. Interventions allow patients with impaired urinary function to be reintroduced to society. For sexual dysfunction, it is necessary to discuss safe sex and behavioral changes. Regarding risk behaviors, it is necessary to guide the patient/family, adapt language to the education level of these individuals, and help them better accept the condition, among other guidelines.

Conclusion

The development of a nursing care plan for PLHTLV is essential for preventing the rapid progression of disease and the improvement of the quality of life of PLHTLV and should be included in the multidisciplinary approach to the secondary level of prevention of HTLV-1.

Occupational Therapy for People Living With Human T-Lymphotropic Virus 1: Importance and Effectiveness of an Intervention Plan at the Level of Prevention and Rehabilitation

Introduction

Human T-lymphotropic virus 1 (HTLV-1)-associated myelopathy (HAM) restricts activities of daily living (ADLs), affecting health and quality of life. Occupational therapy is used to promote independence during ADL in people living with HTLV (PLHTLV).

Objective

To quantify the clinical aspects, levels of functionality, performance in ADLs and occupational roles of PLHTLV and propose an occupational therapeutic intervention.

Method

A cross-sectional, descriptive, observational study was designed with 40 PLHTLV monitored at two referral laboratories of the Federal University of Pará. The Evandro Chagas Research Institute Neurological Disability Scale (EIPEC-2), the Barthel Index and the Occupational Roles Identification List were applied. The G test and Fisher’s exact test (to identify associations between qualitative variables), the Mann–Whitney test (to identify associations between quantitative variables) and Pearson correlation analysis (to identify associations between the total Barthel Index and EIPEC-2 scores) were performed with Microsoft Excel and BioEstat 5.0, and the significance level was set at p ≤ 0.05.

Results

Motor aspects, the presence of spasticity, sensory aspects, and pain in the lumbar region and lower limbs were significantly (p = 0.0002) higher among symptomatic individuals, who also had more difficulties urinating, traveling up and down stairs and transferring from a chair to a bed. Being a worker, performing housework and socializing (with friends or family members) were the most affected activities among HAM patients.

Conclusion

The impact of HAM on PLHTLV should include an intervention plan with occupational therapists in rehabilitation programs to create an important third-level prevention initiative, which may help achieve short-, medium-, and long-term goals. Asymptomatic PLHTLV should also be able to prevent future ADL impairment.

Very high prevalence of infection with the human T cell leukaemia virus type 1c in remote Australian Aboriginal communities: Results of a large cross-sectional community survey

Infection with the human T cell leukaemia virus type 1 (HTLV-1) subtype C is endemic among Aboriginal people in central Australia. To provide insights into the risk factors for transmission, we conducted the first large-scale, community-based prevalence study in seven remote Aboriginal communities. Residents >2 years old were invited to participate in the study between August 2014 and June 2018. HTLV-1 infection was defined as a positive western blot (WB) test or a positive HTLV-1 PCR. 720 community residents participated in the study (children <15 years, 142; adults, 578). Prevalences for children and adults were 3.5% (5/142) and 36.8% (213/578), respectively, reaching 49.3% (106/215) for those older than 45 years. A wide range of proviral loads were measured for both asymptomatic and symptomatic participants with no difference within groups according to age or gender; however, median PVL was 1.34 log10 higher for symptomatic participants. The adult prevalence of HTLV-1 infection in central Australia is the highest reported worldwide. Sexual contact is likely to be the predominant mode of transmission.

Neurofilament Light in CSF and Plasma Is a Marker of Neuronal Damage in HTLV-1-Associated Myelopathy and Correlates With Neuroinflammation

Background and Objectives

To evaluate the usefulness of CSF and plasma neurofilament light (Nf-L) as a biomarker for human T-cell lymphotropic virus type 1 (HTLV-1)-associated myelopathy (HAM).

Methods

Nf-L, CXCL10, and neopterin were measured by ELISA in 83 CSF samples obtained from 49 individuals living with HTLV-1/2. Plasma Nf-L was also measured by single molecule array. Results were correlated with duration of disease, age, mobility, CSF cell counts, CSF protein, and HTLV-1 proviral load.

Results

Nf-L was detected in all CSF samples (median [range] = 575 [791.8–2,349] pg/mL) and positively correlated with markers of inflammation (CXCL10 (r = 0.733), neopterin (r = 0.499), cell count (r = 0.403), and protein levels (r = 0.693) in CSF; p < 0.0015). There was an inverse correlation between Nf-L and duration of disease (r = −0.584, p < 0.0001). Wheelchair-dependent patients had high concentrations of markers of inflammation and neuronal damage. Concentrations of CXCL10, neopterin, and Nf-L remained elevated in follow-up samples (mean follow-up 5.2 years). Nf-L in plasma correlated with concentration of Nf-L, neopterin, CXCL10, and protein in CSF.

Conclusions

Nf-L in plasma and CSF has potential to be used as a biomarker of disease activity in HAM. Neuronal damage seems to be more intense early in disease but persists long term. Wheelchair-dependent patients have ongoing neuroinflammation.

Blocking HTLV-1/2 silent transmission in Brazil: Current public health policies and proposal for additional strategies

Human T-cell lymphotropic viruses 1 and 2 (HTLV-1/2) are relatively common in Brazil but remain silent and neglected infections. HTLV-1 is associated with a range of diseases with high morbidity and mortality. There is no curative treatment for this lifelong infection, so measures to prevent transmission are essential. This narrative review discusses HTLV-1/2 transmission routes and measures to prevent its continuous dissemination. The public health policies that are currently implemented in Brazil to avoid HTLV-1/2 transmission are addressed, and further strategies are proposed.

Pathogenesis of HTLV-1 infection and progression biomarkers: An overview

Infection by human T-cell lymphotropic virus type 1 (HTLV-1) occurs in lymphocytes, which travel throughout the body, thus affecting several target organs and causing varied clinical outcomes, particularly in populations that are underserved and do not have access to healthcare. However, the mechanism of pathogenesis is not yet fully understood. The TAX and HTLV-1 basic leucine zipper factor (HBZ) proteins maintain viral persistence and affect pathogenesis through cell proliferation and immune and inflammatory responses that accompany each clinical manifestation. TAX expression leads to inhibition of transcription error control, OX40 overexpression, and cell proliferation in adult T-cell leukemia (ATL). OX40 levels are elevated in the central nervous system (CNS), and the expression of TAX in the CNS causes neuronal damage and loss of immune reactivity among patients with HTLV-1-associated myelopathy (HAM). HBZ reduces viral replication and suppresses the immune response. Its cell compartmentalization has been associated with the pathogenesis of HAM (cytoplasmic localization) and ATL (nuclear localization). TAX and HBZ seem to act antagonistically in immune responses, affecting the pathogenesis of HTLV-1 infection. The progression from HTLV-1 infection to disease is a consequence of HTLV-1 replication in CD4⁺ T and CD8⁺ T lymphocytes and the imbalance between proinflammatory and anti-inflammatory cytokines. The compartmentalization of HBZ suggests that this protein may be an additional tool for assessing immune and inflammatory responses, in addition to those already recognized as potential biomarkers associated with progression from infection to disease (including human leukocyte antigen (HLA), killer immunoglobulin-like receptors (KIR), interleukin (IL)-6, IL-10, IL-28, Fas, Fas ligand, interferon (IFN)-γ, tumor necrosis factor (TNF)-α, and mannose-binding lectin).

Brazilian Protocol for Sexually Transmitted Infections 2020: human T-cell lymphotropic virus (HTLV) infection

This article addresses the Human T-lymphotropic virus (HTLV). This subject comprises the Clinical Protocol and Therapeutic Guidelines for Comprehensive Care for People with Sexually Transmitted Infections, published by the Brazilian Ministry of Health. HTLV-1/2 infection is a public health problem globally, and Brazil has the largest number of individuals living with the virus. HTLV-1 causes several clinical manifestations of neoplasm (adult T-cell leukemia/lymphoma) and inflammatory nature, such as HTLV-1-associated myelopathy and other manifestations such as uveitis, arthritis, and infective dermatitis. These pathologies have high morbidity and mortality and negatively impact the quality of life of infected individuals. This review includes relevant information for health authorities professionals regarding viral transmission, diagnosis, treatment, and monitoring of individuals living with HTLV-1 and 2 in Brazil.

HTLV-1/2 transmission can occur through blood transfusion and derivatives, injectable drug use, organ transplantation, unprotected sexual intercourse, and vertical transmission.

Expanding the etiologic spectrum of spastic ataxia syndrome: chronic infection with human T lymphotropic virus type 1

Human T-lymphotropic virus type-1 (HTLV-1) is a neglected infection most often associated with an indolent process. However, a subset of HTLV-1 seropositive patients face the risk to develop life-threatening T-cell lymphoma/leukemia, or the highly disabling and incurable HTLV1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). Over the years, other complications to HTLV-1 have been proposed and debated intensely. One of these, although rare, associations include cerebellar ataxia occurring most often in Japanese patients with manifest HAM/TSP. Here we present a HTLV-1 seropositive patient from the Middle East featuring a slowly progressive cerebellar syndrome with cerebellar atrophy but not evidence of spastic paraparesis. In addition, this patient suffered from autoimmune conditions such as Sjögren’s syndrome and vitiligo which are putatively associated with HTLV-1.

Comparison of functioning and health-related quality of life among patients with HTLV-1, HIV, and HIV-HTLV-1-coinfection

INTRODUCTION:

Human immunodeficiency virus (HIV) and human T-cell leukemia virus-1 (HTLV-1) viruses are associated with a high global burden of disease, and coinfection is a frequently reported event. We aimed to compare the functioning and health-related quality of life (HRQoL) of patients infected with HTLV-1, HIV, and HIV-HTLV-1.

METHODS:

We conducted a cross-sectional study of patients older than 18 years who had an HTLV-1 infection (Group A), HIV infection (Group B), or HIV-HTLV-1 coinfection (Group C). The functioning profiles were evaluated using handgrip strength, Berg balance scale (BBS), timed “up and go” (TUG) test, and 5-m walk test (m/s). We used the World Health Organization Disability Assessment Schedule (WHODAS 2.0) questionnaire to measure disability. The HRQoL was evaluated using a 36-item short-form health survey. For data with parametric and non-parametric distribution, we used analysis of variance with Bonferroni correction and the Kruskal-Wallis test, followed by Dunn’s pairwise tests with Bonferroni correction.

RESULTS:

We enrolled 68 patients in Group A, 39 in Group B, and 29 in Group C. The scores for handgrip strength, BBS, TUG test, all the WHODAS domains, and HRQoL were poorer for Groups A and C than for Group B.

CONCLUSIONS:

Compared to patients with HIV infection, those with HIV-HTLV-1 coinfection and HTLV-1 infection had poor functioning and HRQoL scores. HTLV-1 infection was associated with reduced functioning and HRQoL in patients with a single HTLV-1 infection and HIV-HTLV-1 coinfection.

Immunopathogenesis and Cellular Interactions in Human T-Cell Leukemia Virus Type 1 Associated Myelopathy/Tropical Spastic Paraparesis

HTLV-1-Associated Myelopathy/Tropical Spastic Paraparesis (HAM/TSP) is a neuropathological disorder in 1–3% of individuals infected with Human T-lymphotropic virus 1 (HTLV-1). This condition is characterized by progressive spastic lower limb weakness and paralysis, lower back pain, bladder incontinence, and mild sensory disturbances resembling spinal forms of multiple sclerosis. This disease also causes chronic disability and is therefore associated with high health burden in areas where HTLV-1 infection is endemic. Despite various efforts in understanding the virus and discovery of novel diagnostic markers, and cellular and viral interactions, HAM/TSP management is still unsatisfactory and mainly focused on symptomatic alleviation, and it hasn’t been explained why only a minority of the virus carriers develop HAM/TSP. This comprehensive review focuses on host and viral factors in association with immunopathology of the disease in hope of providing new insights for drug therapies or other forms of intervention.

Loop-Mediated Isothermal Amplification (LAMP) Assay for Rapid and Accurate Confirmatory Diagnosis of HTLV-1/2 Infection

Laboratory diagnosis of human T-lymphotropic viruses (HTLV) 1 and 2 infection is performed by serological screening and further confirmation with serological or molecular assays. Thus, we developed a loop-mediated isothermal nucleic acid amplification (LAMP) assay for the detection of HTLV-1/2 in blood samples. The sensitivity and accuracy of HTLV-1/2 LAMP were defined with DNA samples from individuals infected with HTLV-1 (n = 125), HTLV-2 (n = 19), and coinfected with HIV (n = 82), and compared with real-time polymerase chain reaction (qPCR) and PCR-restriction fragment length polymorphism (RFLP). The overall accuracy of HTLV-1/2 LAMP (95% CI 74.8-85.5%) was slightly superior to qPCR (95% CI 69.5-81.1%) and similar to PCR-RFLP (95% CI 79.5-89.3%). The sensitivity of LAMP was greater for HTLV-1 (95% CI 83.2-93.4%) than for HTLV-2 (95% CI 43.2-70.8%). This was also observed in qPCR and PCR-RFLP, which was associated with the commonly lower HTLV-2 proviral load. All molecular assays tested showed better results with samples from HTLV-1/2 mono-infected individuals compared with HIV-coinfected patients, who present lower CD4 T-cell counts. In conclusion, HTLV-1/2 LAMP had similar to superior performance than PCR-based assays, and therefore may represent an attractive alternative for HTLV-1/2 diagnosis due to reduced working time and costs, and the simple infrastructure needed.

Pooling of sera for human T-cell lymphotropic virus (HTLV) screening in a time of increasing health care expenditure and limited resources

Identifying the true prevalence of human T-cell lymphotropic virus, mostly type 1 (HTLV-1), and the number of patients with HTLV-1-associated diseases, in addition to introducing HTLV-1/2 serology during the prenatal of pregnant women and in individuals infected with other viruses that share transmission routes with HTLV-1, are actions that could help to recognize the importance of this virus by WHO and national health organizations, and to control its transmission/dissemination. As Brazil is endemic to HTLV and there is an increase in health care expenditure, but resources are limited, any strategy that could reduce the cost of HTLV screening is needed and welcomed. This study aimed to determine whether the strategy of pooling sera for HTLV antibody determination is feasible and reduces the costs. Two enzyme immunoassays (EIA Murex HTLV-I+II, Diasorin, UK, and Gold ELISA HTLV-1+2, REM Ind. Com. Ltda., SP, Brazil), and serum samples that resulted in different levels of HTLV-1/2 antibodies by EIA and of which a volume allowed assay validation were employed for analysis. The diagnostic sensitivity and specificity and Cohen's Kappa value, as well as the accuracy and precision were analyzed. After validating the five-sample pool using the EIA Murex (Cohen's Kappa = 1.0), the technique was employed for individual cost comparison in 2,625 serum samples from populations at risk of HTLV infections (HBV, HCV, and HIV-infected individuals). The results from individual and pooled samples confirmed the diagnostic sensitivity (100%) and specificity (100%) of the pooling and a cost minimization varying from 60.7% to 73.6%. In conclusion, the results of this study suggest the use of pooling sera in sero-epidemiological surveillance studies and possibly in prenatal care screening programs in Brazil.

Neurological Aspects of HIV-1/HTLV-1 and HIV-1/HTLV-2 Coinfection

Simultaneous infection by human immunodeficiency viruses (HIV) and human T-lymphotropic viruses (HTLV) are not uncommon since they have similar means of transmission and are simultaneously endemic in many populations. Besides causing severe immune dysfunction, these viruses are neuropathogenic and can cause neurological diseases through direct and indirect mechanisms. Many pieces of evidence at present show that coinfection may alter the natural history of general and, more specifically, neurological disorders through different mechanisms. In this review, we summarize the current evidence on the influence of coinfection on the progression and outcome of neurological complications of HTLV-1/2 and HIV-1.