HTLV-I-associated myelopathy/tropical spastic paraparesis in Brazil: a nationwide survey. HAM/TSP Brazilian Study Group

Dietary Intake and Serum Selenium Levels Influence the Outcome of HTLV-1 Infection

Human T cell leukemia virus type 1 (HTLV-1)-associated myelopathy/tropical spastic paraparesis (HAM/TSP), as the most common neurological emersion related to HTLV-1, is a debilitating and lifelong treating disease with no definitive treatment. Furthermore, it has been determined that dietary compositions (inflammatory and anti-inflammatory) and some micronutrients (such as vitamin D and selenium) have an effect on inflammatory and immune processes and with this background; the study was done to compare the nutritional status between age- and sex-matched with infected and non-infected HTLV-1. In a multi-center setting, 70 healthy controls (HCs), 35 asymptomatic carriers (ACs), and 35 HAM/TSP patients were recruited in the HTLV-1 Foundation, Ghaem Hospital, Mashhad University of Medical Sciences, Mashhad, Iran. Nutritional status including anthropometric indices, dietary (micro- and macronutrient) intake, and serum vitamin D, vitamin B12, zinc, and selenium were measured. In anthropometric indices, mean waist circumference (WC) in the carrier group was significantly higher than the patient and the control groups (p = 0.008). In the dietary intake, the patient group received less energy, protein, mono-unsaturated fatty acids (MUFA), and oleic, but more fat than the HTLV-1 carrier and control groups, and these differences were remarkable in three groups (p = 0.002, 0.005, 0.001, 0.01, and 0.001, respectively), whereas the carrier group received more saturated fatty acid and less poly-unsaturated fatty acids (PUFA), linoleic, and linolenic than patient and control groups with a different significant (p = 0.01, 0.007, 0.005, and 0.006, respectively) in three groups. In micronutrient intake, although selenium, zinc, and vitamins B12 and D were lower in the patient group than the carrier and control group, however, no significant differences were observed. In comparison with micronutrient serum concentrations, vitamins B12 and D and selenium in the patient group were lower than the carrier and control groups, but statistically, the considerable difference was found only in the selenium concentration (p = 0.001). The study showed that there were differences in dietary intake (including energy, macronutrients, and fatty acids), WC, and selenium serum levels between HAM/TSP patients and HTLV-1 carriers, suggesting that nutritional statues influence the inflammatory immune response in HTLV-1 infection.

An update on human T-cell leukemia virus type I (HTLV-1)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) focusing on clinical and laboratory biomarkers

Human T-cell leukemia virus type I (HTLV-1)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is a rare inflammatory disease causing unremitting and progressive neurological disorders, such as spastic paraparesis, neurogenic bladder, and sensory disturbance of the lower extremities. Although there is no cure, immune-modulating agents such as corticosteroids are most widely used to slow disease progression. Biomarkers for the clinical assessment of HAM/TSP should be identified because the prediction of functional prognosis and the assessment of treatment efficacy are challenging due to the slowly progressive nature of the disease. The lack of surrogate biomarkers also hampers clinical trials of new drugs. This review summarizes biomarker candidates for the clinical assessment of patients with HAM/TSP. Most of the reported biomarker candidates are associated with viral components or inflammatory mediators because immune dysregulation provoked by HTLV-1 infection is thought to cause chronic inflammation and damage the spinal cord of patients with HAM/TSP. Although information on the diagnostic accuracy of most of the reported biomarkers is insufficient, several molecules, including inflammatory mediators such as CXCL10 and neopterin in the cerebrospinal fluid, have been suggested as potential biomarkers of functional prognosis and treatment response. Several clinical trials for HAM/TSP are currently underway, and we expect that these studies will provide not only evidence pertaining to treatment, but also novel findings regarding the utility of biomarkers in this disease. The establishment of clinical biomarkers will improve patient care and promote the development of therapies for HAM/TSP.

Intrarater and interrater agreement and reliability of vestibular evoked myogenic potential triggered by galvanic vestibular stimulation (galvanic-VEMP) for HTLV-1 associated myelopathy testing

BACKGROUND

The vestibular evoked myogenic potential triggered by galvanic vestibular stimulation (galvanic-VEMP) has been used to assess the function of the vestibulospinal motor tract and is a candidate biomarker to predict and monitor the human T-cell lymphotropic virus type 1 (HTLV-1) associated myelopathy (HAM). This study determined the agreement and reliability of this exam.

METHODS

Galvanic-VEMP was performed in 96 participants, of which 24 patients presented HAM, 27 HTLV-1-asymptomatic carriers, and 45 HTLV-1-negative asymptomatic controls. Galvanic vestibular stimulation was achieved by passing a binaural and bipolar current at a 2 milliamperes (mA) intensity for 400 milliseconds (ms) between the mastoid processes. Galvanic-VEMP electromyographic wave responses of short latency (SL) and medium latency (ML) were recorded from the gastrocnemius muscle. Intrarater (test-retest) and interrater (two independent examiners) agreement and reliability were assessed by standard error of measurement (SEM), coefficient of repeatability (CR), intraclass correlation coefficient (ICC), and Kappa coefficient.

RESULTS

In the total sample (n = 96), SL and ML medians were 56 ms (IQR 52-66) and 120 ms (IQR 107-130), respectively. The intrarater repeatability measures for SL and ML were, respectively: SEM of 6 and 8 ms; CR of 16 and 22 ms; ICC of 0.80 (p<0.001) and 0.91 (p<0.001); and a Kappa coefficient of 0.53 (p<0.001) and 0.82 (p<0.001). The interrater reproducibility measures for SL and ML were, respectively: SEM of 3 and 10 ms; CR of 8 and 27 ms; ICC of 0.95 (p<0.001) and 0.86 (p<0.001); and a Kappa coefficient of 0.77 (p<0.001) and 0.88 (p<0.001).

CONCLUSION

Galvanic-VEMP is a reliable and reproducible method to define the integrity of the vestibulospinal tract. Longitudinal studies will clarify its validity in the clinical context, aimed at achieving an early diagnosis and the monitoring of HAM.

Clinical and laboratory features of HTLV-I asymptomatic carriers and patients with HTLV-I-associated myelopathy/tropical spastic paraparesis from the Brazilian Amazon

Clinical and laboratory parameters including blood and cerebrospinal fluid (CSF) neopterin were investigated in human-T-lymphotropic-virus-type-I associated-myelopathy/tropical-spastic-paraparesis-HAM/TSP and in HTLV-I carriers. HAM/TSP (n = 11, 2 males/9 females, median age = 48 years), recently diagnosed HTLV-I carriers (n = 21, 15 females/6 males, median age = 44 years), healthy individuals (n = 20, 10 males/10 females, median age = 34.6 years) from the Brazilian Amazon (Manaus, Amazonas State) were investigated. Neopterin was measured (IBL ELISA Neopterin, Germany) in serum samples of all the participants, in CSF of 9 HAM/TSP patients as well as in 6 carriers. In HAM/TSP patients, CSF cell counts, protein and glucose were measured, the Osame’s motor-disability-score/OMDS was determined, and brain/spinal cord magnetic-resonance-imaging (MRI) was performed. HAM/TSP patients had normal CSF glucose, leukocyte counts; and normal protein levels predominated. Brain-MRI showed white-matter lesions in 7 out of 11 HAM/TSP patients. OMDS varied from 2-8: 9 were able to walk, 2 were wheel-chair-users. The median serum neopterin concentration in HAM/TSP patients was 6.6 nmol/ L; min. 2.8- max. 12.5 nmol/ L); was lower in carriers (4.3 nmol/L; min. 2.7- max. 7.2 nmol/ L) as well as in healthy participants (4.7 nmol/ L; min. 2.7- max. 8.0 nmol/ L) (p < 0.05). CSF neopterin concentrations in HAM/TSP patients were higher than in serum samples, and higher compared to carriers (p < 0.05). Carriers had similar serum-CSF neopterin concentrations compared to healthy participants. Variable clinical and laboratory profiles were seen in HAM/TSP patients, however our results support the neopterin measurement as a potential biomarker of disease activity.

Nation-wide epidemiological study of Japanese patients with rare viral myelopathy using novel registration system (HAM-net)

Background

At least one million people are infected with human T-lymphotropic virus type 1 (HTLV-1) in Japan, a small percentage of whom develop HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) or adult T-cell leukemia/lymphoma (ATLL). Patients with HAM/TSP suffer from progressively worsening myelopathic symptoms, such as motor disability and bladder dysfunction, and may become wheelchair-bound or even bedridden.

Methods

To learn more about this rare, debilitating disease, we established the national registration system “HAM-net” in March 2012. We continuously obtain detailed data from enrolled patients using the registration forms and an annual telephone interview. In this retrospective study, we describe the demographics and clinical histories of 383 registered patients from all over Japan.

Results

Patients were diagnosed at a median of 53 years old, long after disease onset at 45. Most (55.3 %) were originally from the southernmost regions, Kyushu and Okinawa. The main initial symptoms were difficulty walking (81.9 %), urinary dysfunction (38.5 %), and lower limb sensory disturbances (13.9 %). Many patients reported frequent leg numbness and leg pain, and the vast majority required medical intervention for urinary symptoms and constipation. A median of 8 years elapsed from the onset of motor symptoms to Osame Motor Disability Score (OMDS) 5 (requiring unilateral support), 12.5 years to OMDS 6 (requiring bilateral support), and 18 years to OMDS 9 (unable to walk). Health Assessment Questionnaire - Disability Index (HAQ-DI) tasks related to mobility, as opposed to hand motions, were very difficult for HAM/TSP patients and well-correlated with OMDS. Scores on the MOS 36-Item Short-Form Health Survey (SF-36) indicated that physical functioning was severely impaired in HAM/TSP patients. Patients with a history of blood transfusion (19.1 %) were older and suffered from more severe disability as indicated by their high HAQ-DI scores. Patients with a family history of HAM/TSP (8.4 %) were younger and had relatively mild symptoms given their long disease durations; many (15.6 %) also had a relative with ATLL.

Conclusions

The HAM-net national registration system has been an effective tool for gathering personal and clinical data from HAM/TSP patients scattered throughout Japan. We expect to conduct many retrospective and prospective epidemiological studies using HAM-net in the future.

Synaptic Plasticity and Neurological Disorders in Neurotropic Viral Infections

Based on the type of cells or tissues they tend to harbor or attack, many of the viruses are characterized. But, in case of neurotropic viruses, it is not possible to classify them based on their tropism because many of them are not primarily neurotropic. While rabies and poliovirus are considered as strictly neurotropic, other neurotropic viruses involve nervous tissue only secondarily. Since the AIDS pandemic, the interest in neurotropic viral infections has become essential for all clinical neurologists. Although these neurotropic viruses are able to be harbored in or infect the nervous system, not all the neurotropic viruses have been reported to cause disrupted synaptic plasticity and impaired cognitive functions. In this review, we have discussed the neurotropic viruses, which play a major role in altered synaptic plasticity and neurological disorders.

Immunological and viral features in patients with overactive bladder associated with human T-cell lymphotropic virus type 1 infection

The majority of patients infected with human T-cell lymphotropic virus-type 1 (HTLV-1) are considered carriers, but a high frequency of urinary symptoms of overactive bladder, common in HTLV-1 associated myelopathy/tropical spastic paraparesis (HAM/TSP) have been documented in these patients. The aim of this study was to determine if immunological and viral factors that are seen in HAM/TSP are also observed in these patients. Participants were classified as HTLV-1 carriers (n = 45), HTLV-1 patients suffering from overactive bladder (n = 45) and HAM/TSP (n = 45). Cells from HTLV-1 overactive bladder patients produced spontaneously more proinflammatory cytokines than carriers. TNF-α and IL-17 levels were similar in HAM/TSP and HTLV-1 overactive bladder patients. High proviral load was found in patients with overactive bladder and HAM/TSP and correlated with proinflammatory cytokines. In contrast with findings in patients with HAM/TSP, serum levels of Th1 chemokines were similar in HTLV-1 overactive bladder and carriers. Exogenous addition of regulatory cytokines decreased spontaneous IFN-γ production in cell cultures from HTLV-1 overactive bladder patients. The results show that HTLV-1 overactive bladder and HAM/TSP patients have in common some immunological features as well as similar proviral load profile. The data show that HTLV-1 overactive bladder patients are still able to down regulate their inflammatory immune response. In addition, these patients express levels of chemokines similar to carriers, which may explain why they have yet to develop the same degree of spinal cord damage as seen in patients with HAM/TSP. These patients present symptoms of overactive bladder, which may be an early sign of HAM/TSP.

Epidemiological Aspects and World Distribution of HTLV-1 Infection

The human T-cell leukemia virus type 1 (HTLV-1), identified as the first human oncogenic retrovirus 30 years ago, is not an ubiquitous virus. HTLV-1 is present throughout the world, with clusters of high endemicity located often nearby areas where the virus is nearly absent. The main HTLV-1 highly endemic regions are the Southwestern part of Japan, sub-Saharan Africa and South America, the Caribbean area, and foci in Middle East and Australo-Melanesia. The origin of this puzzling geographical or rather ethnic repartition is probably linked to a founder effect in some groups with the persistence of a high viral transmission rate. Despite different socio-economic and cultural environments, the HTLV-1 prevalence increases gradually with age, especially among women in all highly endemic areas. The three modes of HTLV-1 transmission are mother to child, sexual transmission, and transmission with contaminated blood products. Twenty years ago, de Thé and Bomford estimated the total number of HTLV-1 carriers to be 10-20 millions people. At that time, large regions had not been investigated, few population-based studies were available and the assays used for HTLV-1 serology were not enough specific. Despite the fact that there is still a lot of data lacking in large areas of the world and that most of the HTLV-1 studies concern only blood donors, pregnant women, or different selected patients or high-risk groups, we shall try based on the most recent data, to revisit the world distribution and the estimates of the number of HTLV-1 infected persons. Our best estimates range from 5-10 millions HTLV-1 infected individuals. However, these results were based on only approximately 1.5 billion of individuals originating from known HTLV-1 endemic areas with reliable available epidemiological data. Correct estimates in other highly populated regions, such as China, India, the Maghreb, and East Africa, is currently not possible, thus, the current number of HTLV-1 carriers is very probably much higher.

Clinical pathophysiology of human T-lymphotropic virus-type 1-associated myelopathy/tropical spastic paraparesis

Human T-lymphotropic virus type 1 (HTLV-1), a human retrovirus, is the causative agent of a progressive neurological disease termed HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). HAM/TSP is a chronic inflammatory disease of the central nervous system and is characterized by unremitting myelopathic symptoms such as spastic paraparesis, lower limb sensory disturbance, and bladder/bowel dysfunction. Approximately 0.25-3.8% of HTLV-1-infected individuals develop HAM/TSP, which is more common in women than in men. Since the discovery of HAM/TSP, significant advances have been made with respect to elucidating the virological, molecular, and immunopathological mechanisms underlying this disease. These findings suggest that spinal cord invasion by HTLV-1-infected T cells triggers a strong virus-specific immune response and increases proinflammatory cytokine and chemokine production, leading to chronic lymphocytic inflammation and tissue damage in spinal cord lesions. However, little progress has been made in the development of an optimal treatment for HAM/TSP, more specifically in the identification of biomarkers for predicting disease progression and of molecular targets for novel therapeutic strategies targeting the underlying pathological mechanisms. This review summarizes current clinical and pathophysiological knowledge on HAM/TSP and discusses future focus areas for research on this disease.

[HTLV-1 associated myelopathy: clinical and epidemiological profile in a 10-year case series study]

INTRODUCTION

Human T cell lymphotropic virus type 1 (HTLV-I) myelopathy (HAM/TSP) is a progressive disabling disorder. This work aimed to analyze clinical features and epidemiology in a sample of HAM/TSP.

METHODS

All HTLV-1 infected patients with diagnostic criteria for HAM/TSP, consecutively admitted to the Sarah Hospital from 1998 to 2007, were included in the study.

RESULTS

206 patients (67% females; mean age: 53.8 years-old) were diagnosed with HAM/TSP. The mean time of evolution was 9.0 years. The most common neurological symptoms were chronic progressive spastic paraparesis, spasticity, pain, neurogenic bladder and neurogenic bowel. The neurological findings were hyperreflexia, Babinsky, Hoffman and peripheral neuropathy. Pain, spasticity and spinal cord atrophy, observed in MRI, were associated with time of disease (p<0.05).

CONCLUSIONS

HAM/TSP is a very disabling disorder, in which pain is reported early, while spasticity and thoracic spinal cord atrophy appear in a later phase of the disease. Cases of HAM/TSP exist with a probable vertical viral transmission.

Prevalence of erectile dysfunction in HTLV-1-infected patients and its association with overactive bladder

OBJECTIVES

To determine the prevalence of erectile dysfunction (ED) in human T-cell lymphotropic virus type I (HTLV-I)-infected patients, and its association with overactive bladder (OB).

METHODS

In a cross-sectional study, 111 male patients with positive serology for HTLV-I (by enzyme-linked immunosorbent assay and Western blot) were examined between October 2003 and December 2006. Exclusion criteria were age <18 and >80 years, other neurological diseases, penile prosthesis, neoplasm, and psychological and mental disease. Patients were evaluated by a urologist and neurologist. ED was determined by application of the abridged form of 5-item International Index of Erectile Function (IIEF-5). ED was defined as IIEF-5 <or= 21. OB was determined by International Continence Society criteria. Using the Expanded Disability Status Scale (EDSS) to determine disautonomy status, a neurologist classified all patients as either asymptomatic carriers (EDSS = 0), "oligosymptomatic myelopathy" (EDSS > 0 e <or= 2), or HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP); (EDSS > 2). Diagnosis of HAM/TSP was performed according to World Health Organization recommendations.

RESULTS

Of the total of 111 patients, 6 were excluded and 105 were analyzed. The mean age was 48 +/- 10.7 years. ED was observed in 55.2%. ED was documented in all patients who had HAM/TSP, in 79% of the group with EDSS > 0 and <or=2, and in 35.9% of HTLV-1-infected individuals with EDSS = 0. OB was detected in 93.75%, 33.3%, and 4.6%, respectively. Moreover, there was an association observed between ED and OB.

CONCLUSIONS

ED is a frequent disease in HTLV-I-infected individuals, and the prevalence is directly correlated to the degree of neurological disability measured by EDSS. ED was strongly associated with OB symptoms.

Perfil funcional de locomoção em um grupo de pacientes com lesão medular atendidos em um centro de reabilitação

OBJETIVO: descrever o perfil de locomoção de um grupo de pacientes com lesão medular (LM), correlacionando-o com as características da amostra. MÉTODOS: setenta pacientes (50 com LM traumática e 20 com LM não-traumática). Instrumentos: Classificação Funcional da Marcha Modificada (CFMM), WISCI-II, Escala de Ashworth Modificada (EAM), Classificação AIS, Lower Extremities Muscle Score (AIS-LEMS). Estatística: descritiva, comparação entre grupos, testes de correlação considerando p<0,05. RESULTADOS: a média da idade dos pacientes foi de 36 anos; 72,9% dos pacientes eram homens; tempo médio de lesão: 4,7 anos; AIS: 38,6% A, 10% B, 22,8% C, 28,6% D; Nível de lesão: 32,8% cervical, 52,9% torácico, 14,3% lombossacro. Causas mais frequentes: PAF 30%; acidente automobilístico 18,6%; CFMM: CR 34,3%; marcha terapêutica 20%; domiciliar 12,8%; comunitária 32,9%. WISCI-II: 7,5. AIS-LEMS: 13,4. Houve diferença entre os grupos LM traumática e não-traumática quanto à idade, sexo, AIS, AIS-LEMS, CFMM e WISCI-II. Correlações significativas: AIS correlacionou-se positivamente com CFMM, WISCI-II, AIS-LEMS. Nível de lesão correlacionado negativamente com EAM. AIS-LEMS positivamente com a AIS, CFMM, WISCI-II e negativamente com apoio e órteses na deambulação. O tempo de lesão e a presença de dor incapacitante não se correlacionaram com as variáveis estudadas. CONCLUSÕES: o grupo de LM traumática era composto por pacientes mais jovens e com maior prevalência de lesão completa. A idade se correlacionou com o uso de aparelhos de auxílio à marcha e órteses. O desempenho funcional da marcha esteve ligado à AIS e ao AIS-LEMS, sendo que a marcha comunitária necessitou de um AIS-LEMS de pelo menos 32 pontos.

HTLV-1 and neurological conditions: when to suspect and when to order a diagnostic test for HTLV-1 infection?

HTLV-1 is a retrovirus associated with a myriad of clinical conditions, especially hematological and neurological ones. Regarding nervous system diseases, it is of utmost importance to select those cases in which HTLV-1 infection could really be associated. This is particularly true for patients from endemic areas and for HIV-infected patients and drug users, since that these groups are at a higher risk for HTLV infection. This caution in selecting neurological patients for HTLV diagnostic tests is justified by the fact that in some circumstances the seropositivity may merely represent an epiphenomenon. In this paper we enroll some neurological conditions that have been associated with HTLV-1/2 infection in the literature and discuss the real need for HTLV-1/2 diagnostic tests in each one. Because HIV/HTLV-co-infected patients seem to be at an increased risk for neurological diseases development, a special consideration about this matter is also made.

Role of resident CNS cell populations in HTLV-1-associated neuroinflammatory disease

Human T cell leukemia virus type 1 (HTLV-1), the first human retrovirus discovered, is the etiologic agent for a number of disorders; the two most common pathologies include adult T cell leukemia (ATL) and a progressive demyelinating neuroinflammatory disease, HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). The neurologic dysfunction associated with HAM/TSP is a result of viral intrusion into the central nervous system (CNS) and the generation of a hyperstimulated host response within the peripheral and central nervous system that includes expanded populations of CD4+ and CD8+ T cells and proinflammatory cytokines/chemokines in the cerebrospinal fluid (CSF). This robust, yet detrimental immune response likely contributes to the death of myelin producing oligodendrocytes and degeneration of neuronal axons. The mechanisms of neurological degeneration in HAM/TSP have yet to be fully delineated in vivo and may involve the immunogenic properties of the HTLV-1 transactivator protein Tax. This comprehensive review characterizes the available knowledge to date concerning the effects of HTLV-1 on CNS resident cell populations with emphasis on both viral and host factors contributing to the genesis of HAM/TSP.

Subacute progression of human T-lymphotropic virus type I-associated myelopathy/tropical spastic paraparesis

Although human T-lymphotropic virus type I (HTLV-I)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is usually described as a chronic disabling disease, a rapid course over months or even weeks has been reported in some patients. The authors describe the clinical features of HAM/TSP in a Brazilian cohort and evaluate the prevalence of patients with a subacute progression of the disease. This was defined as the requirement of a wheelchair during the first 2 years after the onset of symptoms. Patients with this subacute course and patients with the chronic clinical course were compared in terms of their HTLV-I proviral loads (PLs) using real-time polymerase chain reaction (PCR). Seven out of 88 patients (7.9%) had a subacute progression. All patients were women and 5/7 acquired HTLV-I through sexual contact. There was no significant difference in the real-time PLs between the group with subacute evolution (mean 8.5 copies/100 cells, range 6.03 to 12.09) and those patients with a typical course of disease (mean 11.34 copies/100 cells, range 0.4 to 67.72) (P = .68), suggesting that factors other than the number of infected cells are implicated in the development of such an aggressive course of disease. Early recognition of this subgroup is important because immunosuppressive treatment might be beneficial if instituted promptly.

Human T-lymphotropic virus 1: recent knowledge about an ancient infection

Human T-lymphotropic virus 1 (HTLV-1) has infected human beings for thousands of years, but knowledge about the infection and its pathogenesis is only recently emerging. The virus can be transmitted from mother to child, through sexual contact, and through contaminated blood products. There are areas in Japan, sub-Saharan Africa, the Caribbean, and South America where more than 1% of the general population is infected. Although the majority of HTLV-1 carriers remain asymptomatic, the virus is associated with severe diseases that can be subdivided into three categories: neoplastic diseases (adult T-cell leukaemia/lymphoma), inflammatory syndromes (HTLV-1-associated myelopathy/tropical spastic paraparesis and uveitis among others), and opportunistic infections (including Strongyloides stercoralis hyperinfection and others). The understanding of the interaction between virus and host response has improved markedly, but there are still no clear surrogate markers for prognosis and there are few treatment options.

Clinical manifestations associated with HTLV type I infection: a cross-sectional study

Human T-lymphotropic virus type I (HTLV-I) causes HTLV-I-associated myelopathy/tropical spastic paraparesis and adult T cell leukemia in a small percentage of infected individuals. HTLV-I infection is increasingly associated with clinical manifestations. To determine the prevalence of clinical manifestations in HTLV-I infected individuals, we conducted a cross-sectional study of 115 HTLV-I-infected blood donors without myelopathy and 115 age- and sex-matched seronegative controls. Subjects answered a standardized questionnaire and underwent physical examination. Compared with controls, HTLV-I-infected subjects were more likely to report arm or leg weakness (OR = 3.8, 95% CI: 1.4-10.2; OR = 4.0, 95% CI: 1.6-9.8, respectively), hand or foot numbness (OR = 2.1, 95% CI: 1.1-3.9; OR = 4.8, 95% CI: 2.0-11.7, respectively), arthralgia (OR = 3.3, 95% CI: 1.7-6.4), nocturia (OR = 2.7, 95% CI: 1.04-6.8), erectile dysfunction (OR = 4.0, 95% CI: 1.6-9.8), and to have gingivitis (OR = 3.8, 95% CI: 1.8-7.9), periodontitis (OR = 10.0, 95% CI: 2.3-42.8), and dry oral mucosa (OR = 7.5, 95% CI: 1.7-32.8). HTLV-I infection is associated with a variety of clinical manifestations, which may occur in patients who have not developed myelopathy.

The HTLV-1 neurological complex

Human T-cell lymphotropic virus type 1 (HTLV-1) is a retrovirus that infects about 20 million people worldwide and causes immune-mediated diseases of the nervous system. The classic neurological presentation of HTLV-1 infection is a myelopathy called HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). However, HAM/TSP is not the only neurological outcome that can result from HTLV-1 infection. In this Personal View, we show that HTLV-1 has a broader neurological spectrum than the names HAM/TSP suggest and that people infected with this virus can present with various isolated or assorted syndromes.

Proposal for diagnostic criteria of tropical spastic paraparesis/HTLV-I-associated myelopathy (TSP/HAM)

After the first description of TSP/HAM in 1985 and the elaboration of WHO's diagnostic criteria in 1988, the experience of the professionals in this field has increased so that a critical reappraisal of these diagnostic guidelines was considered timely. Brazilian neurologists and observers from other countries met recently to discuss and propose a modified model for diagnosing TSP/HAM with levels of ascertainment as definite, probable, and possible, according to myelopathic symptoms, serological findings, and/or detection of HTLV-I DNA and exclusion of other disorders.

Lack of tax diversity for tropical spastic paraparesis/human T-cell lymphotropic virus type 1 (HTLV-I) associated myelopathy development in HTLV-I-infected subjects in São Paulo, Brazil

The product of human T-cell lymphotropic virus type 1 (HTLV-1) tax gene has a transactivating effect of the viral and cellular gene expression. Genetic variations in this gene have been correlated with differences in clinical outcomes. Based upon its diversity, two closely related substrains, namely tax A and tax B, have been described. The tax A substrain has been found at a higher frequency among human T-cell leukemia virus type 1 (TSP/HAM) patients than among healthy HTLV-I-infected asymptomatic subjects in Japan. In this study, we determined the distribution of tax substrains in HTLV-I-infected subjects in the city of São Paulo, Brazil. Using the ACCII restriction enzyme site, we detected only tax A substrain from 48 TSP/HAM patients and 28 healthy HTLV-I carriers. The sequenced tax genes from nine TSP/HAM patients and five asymptomatic HTLV-I carriers showed a similar pattern of mutation, which characterizes tax A. Our results indicate that HTLV-I tax subtypes have no significant influences on TSP/HAM disease progression. Furthermore, monophyletic introduction of HTLV-I to Brazil probably occurred during the African slave trade many years ago.

Disability and determinants of gait performance in tropical spastic paraparesis/HTLV-I associated myelopathy (HAM/TSP)

STUDY DESIGN

Cross-sectional.

OBJECTIVES

The aim of this survey is to describe the disability profile in a group of tropical spastic paraparesis/HTLV-I-associated myelopathy patients, identifying the requirements for community ambulation.

SETTING

Tertiary care unit, Rio de Janeiro, Brazil.

METHODS

Seventy-two patients were assessed (49 female and 23 male), referred by tertiary care centers, when a clinical protocol was applied.

RESULTS

The sample had an average age of 40 years and an average of 137 months of duration of the disease. The most prevalent aspects of disability found were in gait and sphincter control areas. A total of 72% of the patients were community ambulators and 17% were restricted to wheel chair. Age, strength and low-back pain interfere in activities of daily living (P<0.05). A positive correlation was found between community ambulation and the knee extensors (r=0.80) and ankle plantar flexors (r=0.74). Strength, age, low-back pain, duration of disease, asymmetric onset of the symptoms and spasticity interfered in the ability to walk (P<0.05). A rehabilitation program was proposed focusing on modifiable factors that affect disability level.

CONCLUSION

It was possible to describe the profile of disability in this group of patients, identifying the requirements to the community ambulation.

Skin reactivity to aeroallergens is reduced in human T-lymphotropic virus type I-infected healthy blood-donors (asymptomatic carriers)

BACKGROUND

A type 2 immune response, characterized by high levels of interleukin-4 and immunoglobulin E synthesis is a hallmark of respiratory allergic diseases. Individuals infected with human T-lymphotropic virus type I (HTLV-I) virus have spontaneous T-cell proliferation and increased interferon gamma production, which are immunological functions associated with a type 1 immune response.

OBJECTIVE

To determine the frequency of asthma and rhinitis symptoms and immediate skin reactivity to aeroallergens in HTLV-I infected individuals, compared with noninfected subjects.

METHODS

Cross sectional study of 101 HTLV-I infected and 101 control uninfected blood donors, assessed by enzyme-linked immunosorbent assay and Western blot assays. The subjects were age and sex-matched, identified as presenting allergy history by questionnaire, which was complemented by a complete clinical examination and skin prick tests for aeroallergens.

RESULTS

The frequency of atopy was lower in infected than uninfected subjects, 14.9 and 29.7% (P = 0.017), respectively. Skin reactivity to Dermatophagoides pteronissynus, Dermatophagoides farinae and Blomia tropicalis were the most frequently observed among all the tested antigens in both groups. Skin reactivity to histamine was also reduced in the infected individuals compared with uninfected subjects (medians 4.0 vs 5.0, respectively; P < 0.0001). Infection by HTLV-I was found to be a factor of protection to atopy (RP 0.44; P = 0.005).

CONCLUSIONS

The HTLV-I infection reduces the frequency of respiratory allergy and skin reactivity to aeroallergens.

Establishment of HTLV-I-infected cell lines from peripheral blood mononuclear cells of Brazilian patients

To investigate epidemiological and pathogenetic features of HTLV-I infection, a cohort of carriers has been followed at the USP Teaching Hospital since 1991. This study describes the establishment of cell lines from peripheral blood mononuclear cells (PBMC) of infected subjects. Ex vivo PBMC were cultured with those from a seronegative donor and morphologic evidence of cell transformation was obtained after 90 days with detection of multinucleated cells exhibiting cerebriform nuclei. Integration of HTLV-I proviral DNA and expression of viral antigens was demonstrated in culture by PCR and immunofluorescence. Cell lines were maintained for 240 days, gradually weaned from exogenous IL-2. Immunophenotyping of cell lines on flow cytometry yielded evidence of cell activation. Establishment of HTLV-I-infected cell lines from ex vivo PBMC is feasible and may be useful for studies on lymphocyte phenotypic changes and on mechanisms of HTLV-induced cell proliferation. Moreover they may be used with diagnostic purposes in immunofluorescence tests.

HTLV-I associated myelopathy/tropical spastic paraparesis in a 7-year-old boy associated with infective dermatitis

HTLV-I associated myelopathy/tropical spastic paraparesis (HAM/TSP) is a chronic myelopathy characterized by a slowly progressive spastic paraparesis and sphincter disturbances beginning in adulthood. Only eight well-documented cases occurring in childhood and adolescence have been described. Infective dermatitis associated to the HTLV-I (IDH) is a chronic eczema of childhood occurring in vertically infected carriers. Here we describe a 7-year-old boy with HAM/TSP and IDH. The neurological manifestations were spastic gait, hyperreflexia of lower limbs, clonus and bilateral Babinski's sign. High levels of HTLV-I antibodies in the serum and in the cerebrospinal fluid were observed. The association of these two diseases and the early onset of HAM/TSP are probably related to a strong humoral anti-HTLV-I response.

HTLV-I in the general population of Salvador, Brazil: a city with African ethnic and sociodemographic characteristics

The city of Salvador has the highest prevalence of HTLV-I among blood donors in Brazil. To study the prevalence of HTLV-I among the general population of Salvador, 30 "sentinel surveillance areas" were selected for the investigation of various infectious diseases, and 1385 individuals within these areas were surveyed according to a simple random sample procedure. ELISA was used to screen plasma samples for antibodies to HTLV-I, and the positive samples were tested by a confirmatory assay (Western blotting). The overall prevalence of HTLV-I was 1.76% (23/1385). Infection rates were 1.2% for males and 2.0% for females. Specific prevalence demonstrated an increasing linear trend with age. No one younger than 13 years of age was infected. Multivariate analysis estimated adjusted odds ratios for the association of HTLV-I with age of 9.7 (3.3; 30.4) for females and 12.3 (1.47; 103.1) for males. Less education and income might be associated with HTLV-I infection in females. Phylogenetic analysis of the long terminal repeat fragments showed that most of the samples belonged to the Latin American cluster of the Transcontinental subgroup (Cosmopolitan subtype). For the entire city of Salvador, it is estimated that approximately 40000 individuals are infected with HTLV-I. Our results suggest multiple post-Colombian introductions of African HTLV-Ia strains in Salvador.

Increased risk of developing peripheral neuropathy in patients coinfected with HIV-1 and HTLV-2

One thousand one hundred fifty-two HIV-1-positive patients were screened for HTLV-2 infection, and the AIDS-free coinfected individuals were consecutively included in a longitudinal study with the aim of investigating the role of HTLV-2 in the progression to AIDS and the development of specific neurologic diseases. Two matched HIV-1-positive/HTLV-2-negative controls for each coinfected individual were also enrolled in the study. HTLV-2 infection was found in 95 (8.2%) of the HIV-1-positive patients, 30 of whom were followed up for a median of 28.5 months. No significant differences were observed between them and the patients infected with HIV-1 alone in terms of the rate of decline in CD4 cell counts, progression to AIDS, or AIDS mortality, but they had an increased risk of developing peripheral neuropathy (hazard ratio, 3.3; 95% confidence interval, 1.3-8.0; p =.009). One coinfected patient developed myelopathy during the follow-up. In the second part of the study, aimed at preliminarily assessing the effect of highly active antiretroviral therapy (HAART) on the incidence of peripheral neuropathy, we extended our observations to two groups of coinfected and singly infected individuals receiving HAART. An 80% decrease in incidence of peripheral neuropathy was observed among both groups without any significant difference between them. These results support the hypothesis that HTLV-2 plays a role in the development of neurologic abnormalities in HIV-1-infected patients and suggest that the immune reconstitution due to HAART may limit the activity of HTLV-2 as an opportunistic agent.

Identification of human T-lymphotropic virus type I (HTLV-I) subtypes using restricted fragment length polymorphism in a cohort of asymptomatic carriers and patients with HTLV-I-associated myelopathy/tropical spastic paraparesis from São Paulo, Brazil

Although human T-lymphotropic virus type I (HTLV-I) exhibits high genetic stability, as compared to other RNA viruses and particularly to human immunodeficiency virus (HIV), genotypic subtypes of this human retrovirus have been characterized in isolates from diverse geographical areas. These are currently believed not to be associated with different pathogenetic outcomes of infection. The present study aimed at characterizing genotypic subtypes of viral isolates from 70 HTLV-I-infected individuals from São Paulo, Brazil, including 42 asymptomatic carriers and 28 patients with HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP), using restricted fragment length polymorphism (RFLP) analysis of long terminal repeat (LTR) HTLV-I proviral DNA sequences. Peripheral blood mononuclear cell lysates were amplified by nested polymerase chain reaction (PCR) and amplicons submitted to enzymatic digestion using a panel of endonucleases. Among HTLV-I asymptomatic carriers, viral cosmopolitan subtypes A, B, C and E were identified in 73.8%, 7.1%, 7.1% and 12% of tested samples, respectively, whereas among HAM/TSP patients, cosmopolitan A (89.3%), cosmopolitan C (7.1%) and cosmopolitan E (3.6%) subtypes were detected. HTLV-I subtypes were not statistically significant associated with patients' clinical status. We also conclude that RFLP analysis is a suitable tool for descriptive studies on the molecular epidemiology of HTLV-I infections in our environment.

Inhibitory effect of extracts of Brazilian marine algae on human T-cell lymphotropic virus type 1 (HTLV-1)-induced syncytium formation in vitro

Extracts from four species of Brazilian marine algae collected from the Rio de Janeiro State coast were screened to determine the inhibitory effect on HTLV-1-induced syncytium formation. Before performing the syncytium inhibition assay the 50% cytotoxic dose (CyD50) of the algal extracts was evaluated. The antiviral test was carried out in HeLa cells co-cultured with HTLV-I infected T-cell line (C91/PL cells) in the presence of marine algal extracts in the concentration inferior to that corresponding to the CyD50. It was observed that co-cultured cells exposed to Ulva fasciata extract showed 60.2% syncytium inhibition at a concentration of 2.5%. At 5% concentration, Sargassum vulgare and Vidalia obtusiloba extracts presented 78.8 and 76% syncytium inhibition, respectively. The best inhibitory activity was observed with Laminaria abyssalis that presented 100% syncytium inhibition at a concentration of 2.5%. This work shows that extracts of marine algae, mainly L. abyssalis extract, are able to inhibit the cell-to-cell contact essential for the spreading of the virus and could be useful to prevent the infection.