Neurologic abnormalities in HTLV-I- and HTLV-II-infected individuals without overt myelopathy

Novel insights into human T-lymphotropic virus type-1 (HTLV-1) pathogenesis-host interactions in the manifestation of HTLV-1-associated myelopathy/tropical spastic paraparesis

Human T-lymphotropic virus type-1 (HTLV-1) was the first discovered human oncogenic retrovirus, the etiological agent of two serious diseases have been identified as adult T-cell leukaemia/lymphoma malignancy and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP), a debilitating chronic neuro-myelopathy. Despite more than 40 years of molecular, histopathological and immunological studies on HTLV-1-associated diseases, the virulence and pathogenicity of this virus are yet to be clarified. The reason why the majority of HTLV-1-infected individuals (∼95%) remain asymptomatic carriers is still unclear. The deterioration of the immune system towards oncogenicity and autoimmunity makes HTLV-1 a natural probe for the study of malignancy and neuro-inflammatory diseases. Additionally, its slow worldwide spreading has prompted public health authorities and researchers, as urged by the WHO, to focus on eradicating HTLV-1. In contrast, neither an effective therapy nor a protective vaccine has been introduced. This comprehensive review focused on the most relevant studies of the neuro-inflammatory propensity of HTLV-1-induced HAM/TSP. Such an emphasis on the virus-host interactions in the HAM/TSP pathogenesis will be critically discussed epigenetically. The findings may shed light on future research venues in designing and developing proper HTLV-1 therapeutics.

Frequency and characteristics of HTLV in migrants: results from the +Redivi collaborative network in Spain

INTRODUCTION

The objective of this study was to describe the main characteristics of migrants diagnosed with human T-lymphotropic virus (HTLV) infection within the +Redivi Spanish network.

METHODS

Patients with a diagnosis of HTLV type 1 or 2 in +Redivi from October 2009 to December 2020 were included. Diagnosis was based on positive HTLV serology (enzyme-linked immunosorbent assay (ELISA)/chemiluminescent immunoassay (CLIA)) with line immunoassay (LIA)/Western blot with/without polymerase chain reaction (PCR).

RESULTS

A total of 107/17 007 cases (0.6%) had a final diagnosis of HTLV infection: 83 (77.67%) HTLV-1 infections, 6 (5.6%) HTLV-2 infections and 18 (16.8%) non-specified. The majority (76, 71%) were female, median age was 42 years and median time from arrival to Spain until consultation was 10 years. The group included 100 (93.5%) immigrants and 7 (6.6%) visiting friends and relatives (VFR)-immigrants. Most patients were from South America (71, 66.4%), followed by Sub-Saharan Africa (15, 14%) and Central America-Caribbean (13, 12.1%). Around 90% of patients were asymptomatic at presentation and diagnosed as part of screening programs. Median duration of follow-up was 5 years (IQR 2-7). Regarding HTLV-associated conditions, 90 patients (84.2%) had none, 7 (6.5%) had tropical spastic paraparesis , 5 (4.7%) had other associated conditions (dermatitis, uveitis, pulmonary disease), 3 (2.8%) had other neurological symptoms and 2 (1.9%) had adult T-cell leukaemia/lymphoma. No patients with HTLV-2 had HTLV-associated conditions. Four patients (3.7%) died. Concomitant diagnoses were found in 41 (38.3%) patients, including strongyloidiasis in 15 (14%) and HIV co-infection in 4 (3.7%). In 70% of patients, screening of potential contacts was not performed/recorded.

CONCLUSIONS

HTLV infections (the majority due to HTLV-1) were mainly diagnosed in asymptomatic migrants from Latin America (generally long-settled immigrants and the majority female with the consequent implications for screening/prevention). A high rate of association with strongyloidiasis was found. In the majority, screening of potential contacts was not performed, representing a missed opportunity for decreasing the under diagnosis of this infection.

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.

Neurodegenerative disease in association with sexual transmission of human T-cell lymphotropic virus type 2 subtype b in Argentina

BACKGROUND

The aim of this study is to show that human T-cell lymphotropic virus type 2 (HTLV-2) infection produces symptoms resembling those described for HTLV-1-associated myeloneuropathy and to highlight the role of sexual transmission in the silent dissemination of HTLV-2.

METHODS

Patient samples were tested by particle agglutination and indirect immunofluorescence assay. The HTLV type was defined by molecular techniques. Nucleotide sequence analysis of HTLV-2 long terminal repeat region, T cell CD3/CD4 and T cell CD3/CD8 counts and typing of human leucocyte antigen (HLA) alleles A, B, C and DRB1 were also performed.

RESULTS

HTLV-2 subtype b infection was confirmed in two blood donors and their sexual partners. Two patients exhibited distinctive signs and symptoms of progressive neurological disease. Three infected patients carried HLA-C*04. Both patients with neurological disease also carried HLA-A*31 and HLA-DRB1*07 alleles.

CONCLUSIONS

Herein we describe for the first time sexual transmission of HTLV-2 in a non-endemic region of Argentina, highlighting the relevance of this transmission route in HTLV-2 silent dissemination out of the clusters of endemicity. We also provide evidence that HTLV-2 infection causes symptoms resembling those described for HTLV-1-associated myeloneuropathy. The evidence presented herein points to the critical need for public health strategies to reduce the spread of this neglected infection.

Anti-Human T-Cell Leukemia Virus Type 1 (HTLV-1) Antibody Assays in Cerebrospinal Fluid for the Diagnosis of HTLV-1-Associated Myelopathy/Tropical Spastic Paraparesis

The anti-human T-cell leukemia virus type 1 (HTLV-1) antibody assay in common use has changed from the particle agglutination (PA) method to chemiluminescent immunoassay (CLIA) and chemiluminescent enzyme immunoassay (CLEIA). These assays were validated in serum but not in cerebrospinal fluid (CSF). However, anti-HTLV-1 antibody positivity in CSF is a requisite for diagnosing HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). We qualitatively compared the assays in CSF from 47 HAM/TSP patients diagnosed using PA, 15 HTLV-1 carriers (HCs), and 18 negative controls. In determining the positivity or negativity of CSF anti-HTLV-1 antibodies, we used serum cutoff points for CLIA and CLEIA because CSF cutoff points had not been decided. Truth table analysis revealed that the performance of CLIA was closer to that of PA and that CLEIA had low sensitivity. CSF antibodies from HAM/TSP patients were all positive by PA and CLIA but 83.0% positive by CLEIA. CSF antibodies from HCs were positive in 73.3%, 80.0%, and 6.7% by PA, CLIA, and CLEIA, respectively. Receiver operator characteristic curve analysis for CSF revealed that with the default cutoff point used for serum, CLIA and PA had comparable performances and CLEIA was less sensitive. The best performances of CLIA and CLEIA with adjusted cutoff points were 94.8% sensitivity and 95.5% specificity and 89.7% sensitivity and 95.5% specificity, respectively. We conclude that low-sensitivity CLEIA can underdiagnose HAM/TSP and that CLIA is a better alternative to PA in anti-HTLV-1 antibody assay for CSF with the current cutoff points.

Pulmonary Disease Is Associated With Human T-Cell Leukemia Virus Type 1c Infection: A Cross-sectional Survey in Remote Aboriginal Communities

Background

The human T-cell leukemia virus type 1 (HTLV-1) subtype c is endemic to central Australia. We report the first large-scale, community-based, health survey of HTLV-1 and its disease associations in this setting.

Methods

Aboriginal community residents aged >2 years in 7 remote communities were invited to do a health survey that included a questionnaire, spirometry, and clinical examination by a physician blinded to HTLV-1 status, clinical records, and spirometry results. Blood was drawn for HTLV-1 serology and proviral load (PVL). Pulmonary disease was assessed clinically and spirometrically and, where records were available, radiologically after the clinical assessment. Associations between specific diseases and HTLV-1 status were determined using logistic regression, adjusting for available confounders.

Results

Overall, 579 residents (164 children aged 3–17 years; 415 adults) were examined (37.7% of the estimated resident population). HTLV-1 prevalences for children and adults were 6.1% and 39.3%, respectively. No associations were found between HTLV-1 and any assessed clinical condition among children. Chronic pulmonary disease and gait abnormalities were more common among adults with HTLV-1 infection. Adjusted odds ratios among participants with PVL ≥1000 per 105 peripheral blood leukocytes were 7.08 (95% confidence interval [CI], 2.67–18.74; P < .001), 9.81 (95% CI, 3.52–27.35; P < .001), and 14.4 (95% CI, 4.99–41.69; P < .001) for clinically defined chronic pulmonary disease, moderate-severe expiratory airflow limitation, and radiologically determined bronchiectasis/bronchiolitis, respectively, and 5.21 (95% CI, 1.50–18.07; P = .009) for gait abnormalities.

Conclusions

In the first study of HTLV-1 disease associations based on community recruitment and blinded assessment, HTLV-1 infection was strongly associated with pulmonary disease and gait abnormalities.

First Description of Seronegative HTLV-1 Carriers in Argentina

In some areas of Argentina endemic for human T-lymphotropic virus type 1 (HTLV-1), tropical spastic paraparesis is frequent in subjects who lack antibodies against the virus; however, the relevance of this seronegative status in the country has not been investigated. In neighboring countries, HTLV-1 seronegative status has been described in patients with different diseases; however, data regarding features of seronegative HTLV-1 carriers are scarce. We investigated the seronegative status in 124 relatives of 28 HTLV-1 infected subjects from an endemic area in Northwest Argentina. Blood samples and clinical/epidemiological data were collected. Human T-lymphotropic virus type 1 infection was diagnosed by serology and long terminal repeat (LTR) sequence, env and tax gene detection. IgG anti-Tax HTLV-1 antibody, tax gene sequence, and DNA proviral load were also evaluated. Seventy-five percent of the 124 relatives were negative for HTLV-1/2 antibodies; 35.5% were also negative by molecular assays and 64.5% were negative for HTLV-1 LTR and env sequences, but positive for two sequences of HTLV-1 tax gene. Also, 35.7% of these subjects had IgG anti-Tax antibodies. The seronegative HTLV-1 status was significantly associated with male gender, youth, and sensory symptoms/autonomic nervous system dysfunction. High rates of seronegative symptomatic and asymptomatic HTLV-1 carriers in Argentina are described. The evidence highlights that HTLV-1 prevalence may be underestimated worldwide. Larger cohort studies are required to assess disease outcome in these seronegative subjects. Also, the findings emphasize the limitations of ongoing screening assays for diagnosis and blood safety. Therefore, algorithms for HTLV-1 diagnosis should include not only serological but also molecular assays.

Prognosis Markers for Monitoring HTLV-1 Neurologic Disease

Background

Human T-cell lymphotropic virus type 1 (HTLV-1) infection is associated not only with some severe manifestations, such as HTLV-1-associated myelopathy (HAM) and ATLL, but also with other, less severe conditions. Some studies have reported neurologic manifestations that did not meet all the criteria for the diagnosis of HAM in individuals infected with HTLV-1; these conditions may later progress to HAM or constitute an intermediate clinical form, between asymptomatic HTLV-1 carriers and those with full myelopathy. This study evaluated the prognostic value and looked for a possible association of those parameters with the intermediate syndrome (IS) status and HAM status.

Methods

Proviral load (PVL), spontaneous lymphoproliferation, interferon (IFN)-γ spontaneous production was quantified in samples of asymptomatic and HAM patients, as well as patients with IS.

Results

The critical age range was 50-60 years for IS outcome and more of 60 years for HAM outcome, with an increased risk of 2.5-fold for IS and 6.8-fold for HAM. IFN-γ was increased in patients with IS compared with asymptomatic carriers (ACs) (p = 0.007) and in patients with HAM compared with ACs (p = 0.03). Lymphoproliferation was increased in patients with HAM vs ACs (p = 0.0001) and patients with IS (p = 0.0001). PVL was similar between groups.

Conclusion

IFN-γ has high specificity of prediction of subject remain asymptomatic compared with PVL and lymphoproliferation assay tests. IFN-γ has been shown to be a biomarker of progression to intermediate stage and to HAM. The association of other markers with manifestations associated with HTLV-1 infection that does not meet the HAM criteria should be verified.

Neurologic, clinical, and immunologic features in a cohort of HTLV-1 carriers with high proviral loads

A high proviral load (PVL) is recognized as a risk factor for human T cell leukemia virus-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP), but there is a lack of prospective studies evaluating whether or not HTLV-1 carriers with high PVL are at risk of developing HAM/TSP or other HTLV-1-related diseases. Here, we compare the incidence of clinical manifestations and the cytokine levels in 30 HTLV-1 carriers with high (> 50,000 copies/10⁶ PBMC) and an equal number of subjects with low proviral load. Participants were followed for 3 to 16 years (median of 11 years). The PVL, IFN-γ, TNF, and IL-10 levels were quantified at entry and at the end of the follow-up. Among the self-reported symptoms in the initial evaluation, only the presence of paresthesia on the hands was more frequent in the group with high PVL (p < 0.04). The production of IFN-γ was higher in the group with high PVL group (median of 1308 versus 686 pg/ml, p < 0.011) when compared with the control group in the first assessment. There was no difference in the occurrence of urinary symptoms or erectile dysfunction, periodontal disease, Sicca syndrome, and neurologic signs between the two groups during the follow-up. The observation that none of the HTLV-1 carriers with high PVL and with exaggerated inflammatory response progressed to HAM/TSP indicates that other factors in addition to the PVL and an exaggerated immune response are involved in the pathogenesis of HAM/TSP.

Detection of clinical and neurological signs in apparently asymptomatic HTLV-1 infected carriers: Association with high proviral load

Several studies suggest that HTLV-1 infection may be associated with a wider spectrum of neurologic manifestations that do not meet diagnostic criteria for HAM/TSP. These conditions may later progress to HAM/TSP or constitute an intermediate clinical form, between asymptomatic HTLV-1 carriers and those with full myelopathy. Our aim was to determine the prevalence of HTLV-1-associated disease in subjects without HAM/TSP, and the relationship between these findings with HTLV-1 proviral load (PVL). Methods: 175 HTLV-1-infected subjects were submitted to a careful neurological evaluation, during their regular follow up at the HTLV outpatient clinic of the Institute of Infectious Diseases “Emilio Ribas”, São Paulo city, Brazil. Clinical evaluation and blinded standardized neurological screening were performed for all the subjects by the same neurologist (MH). Results: After the neurological evaluation, 133 patients were classified as asymptomatic and 42 fulfilled the criteria for intermediate syndrome (IS). The mean age of the enrolled subjects was 46.3 years and 130 (74.3%) were females. Clinical classification shows that neurological symptoms (p<0.001), visual disorders (p = 0.001), oral conditions (p = 0.001), skin lesions (p<0.001), bladder disorders (p<0.001), and rheumatological symptoms (p = 0.001), were strongly associated to IS, except for disautonomy (p = 0.21). A multivariate analysis revealed that HTLV-1 proviral load, oral conditions, bladder disorders and rheumatological symptoms were independently associated with the IS. Conclusions: We found some early alterations in 42 patients (24%), particularly the presence of previously not acknowledged clinical and neurological symptoms, among subjects previously classified as "asymptomatic", who we reclassified as having an intermediate syndrome.

At least 5–10 million people live with the Human T-Cell Lymphotropic Virus type 1 (HTLV-1) worldwide, and around 0.25–5% of them may develop HTLV-1-associated myelopathy/Tropical spastic paraparesis (HAM/TSP), which is associated with chronic inflammation. In this study, involving 175 HTLV-1-infected subjects originally classified as asymptomatic, we found that 42 of them in reality presented some early clinical conditions, including alterations related not only to the neurological system, but also to the eyes and the skin. We called such conditions intermediate syndrome. Thus, it seems reasonable to suggest that all HTLV-1-infected subjects should be monitored for symptoms that may arise earlier in the course of their infection.

The prevalence of human T-cell leukemia virus in blood donors in China

BACKGROUND

China has not yet incorporated routine human T-lymphotropic virus (HTLV)-1/2 blood donor screening, even though HTLV has been reported in the southeastern coastal region. This study was conducted to investigate the prevalence of HTLV in five major regions across of China.

METHODS

From January 2016 to December 2017, blood samples were collected in 20 blood centers located in different regions of China. These samples were screened for HTLV-1/2 antibodies using enzyme-linked immunosorbent assay (ELISA). If the test samples were reactive, the samples were confirmed with a western blot (WB) assay. If the results of WB were indeterminate, the donor was interviewed after a minimum lapse of 8 weeks. All follow-up samples from donors were tested for anti-HTLV-1/2 with ELISA and WB.

RESULTS

There were 875,453 donor samples tested for anti-HTLV-1/2 by ELISA. In all, 365 samples tested negative, 22 samples tested positive by WB, and 14 samples with HTLV status undetermined due to being lost to follow-up. The prevalences were 11.09, 5.96, 3.16, 2.88 and 0.98 per 100,000 in Xiamen, Changsha, Beijing, Shenzhen, and Nanjing blood center, respectively. The prevalences were 0 per 100,000 for all 15 other blood centers. There was significant differences in the prevalence of HTLV in different regions of China (p = 0.0011).

CONCLUSION

In China, HTLV-1 confirmed positive donors are mainly from southeastern coastal areas. It may be necessary to conduct HTLV screening in these areas to reduce the risk of transfusion-transmitted HTLV.

Incomplete myelopathy and human T cell lymphotropic virus type-1 (HTLV-1)

This was a cross-sectional prospective study. We performed a multivariate statistical analysis of the neurological signs and symptoms of patients infected with human T cell lymphotropic virus type 1 (HTLV-1) in an attempt to separate them into distinct groups and identify clinical-neurological manifestations that could differentiate the various profiles. The study was performed in the city of Belém (state of Pará), located in the Amazon region of Brazil, from 2014 to 2016. We determined muscle strength and tone, reflexes, sensations, sphincter function, gait, and the Expanded Disability Status Scale score among individuals with HTLV-I. We then used exploratory statistical methods in an attempt to find different profiles and establish distinct groups. We analyzed 60 patients with HTLV-1. The filtering of the data, performed with mixed PCA, gave rise to a streamlined database with the most informative data and suggested the formation of three statistically distinct groups: asymptomatic carriers (AC), mono/oligosymptomatic (MOS), and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSPd), AC and MOS (p = 0.002), AC and HAM/TSPd (p < 0.001), and HAM/TSPd and MOS (p = 0.001). The subsequent cluster analysis confirmed the formation of three clusters. The classification and regression tree demonstrated that altered gait was the most important variable for the classification of an individual with HAM/TSPd and that, in the absence of this impairment, hyperreflexia characterized MOS. The present study was able to separate patients infected by HTLV-1 into three clinical groups (AC, HAM/TSPd, and MOS) and identify clinical manifestations that could differentiate the various patient groups.

HTLV-1: A real pathogen or a runaway guest of a diseased cell?

The human T-cell lymphotropic virus type 1 (HTLV-1) is a deltaretrovirus claimed to be aetiologically linked to the adult T-cell leukaemia/lymphoma (ATLL) and associated myelopathy/tropical spastic paraparesis (HAM/TSP) besides other minor pathologies. HTLV-1 infection is worldwide distributed, despite its heterogeneous prevalence. Environmental factors and host-genetic background are very likely to determine the epidemiological profile of HTLV-1 prevalence and related disease confinement in distinct human ethnic populations and geographical coordinates, which raises the question if the virus is a real pathogen or a runaway well-organized packed genome of a burden host cell near death process. New methodological approaches need to be proposed and applied in order to prove or discard the hypotheses emerged in the present review.

The relationship between atopy and neurological manifestations in HTLV-1 infection

INTRODUCTION

Human T-cell lymphotropic virus type 1 (HTLV-1)induces exaggerated Th1 responses, whereas atopy is associated with exacerbated Th2 responses.

METHODS

Here, a cross-sectional study compared the prevalence of atopy in HTLV-1 carriers and HAM/TSP patients. It also compared the spontaneous cytokine production in HTLV-1-infected individuals. A retrospective cohort study evaluated the development of neurological manifestations in atopic and non-atopic carriers.

RESULTS

Atopic HAM/TSP patients with high IFN-γ production exhibited higher IL-5 levels than non-atopic patients. Allergic rhinitis accelerated the development of Babinski signals and overactive bladders.

CONCLUSIONS

Abnormal Th1 and Th2 responses coexist in HTLV-1-infected individuals and allergic diseases may worsen the clinical course of HTLV-1 infections.

No significant HTLV seroprevalence in German people who inject drugs

Background

Although human T-lymphotropic virus (HTLV) is transmitted via the same routes as human immunodeficiency virus (HIV), its worldwide seroprevalence differs drastically because HTLV is transmitted mainly via infected cells rather than free virus. The sharing of needles and other equipment places people who inject drugs (PWID) at particularly high-risk for such blood-borne diseases.

Methods

To validate the methodology used to process and analyze the dried blood spots (DBS) utilized in the study, dried serum spots (DSS) with dilutions of sera from known HTLV infected individuals were analyzed by ELISA and Western blot. DBS collected between 2011 and 2015 from 2,077 PWID in eight German cities recruited by respondent-driven sampling were tested for HTLV-specific antibodies.

Results

The validation demonstrated that the use of DSS allowed identification of samples with even low titers of HTLV-specific antibodies, although a confirmatory Western blot with an additional venous blood sample would often be required. Despite numerous HIV and HCV positive individuals being identified within the study population, none tested positive for HTLV.

Conclusion

While the HIV and HCV prevalences in German PWID are comparable to those in other European countries, the very low prevalence of HTLV reflects the situation in the general population.

Rate of positive autoimmune markers in Human T lymphotropic virus type 1 carriers: a case-control study from Iran

AIM

Human T lymphotropic virus type 1 (HTLV-1) infection with high prevalence in the north-east of Iran, particularly in Mashhad, can lead to adult T-cell leukemia (ATL) and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) and a variety of autoimmune diseases. The aim of the study was to examine the presence of autoimmune markers in HTLV carries.

METHODS

Serum samples were obtained from blood donors in Mashhad, northeastern Iran. One hundred and five HTLV-1 positive (cases) and 104 age- and sex-matched HTLV-1 negative donors (controls) were assessed for presence of serum autoimmune markers by enzyme-linked immunosorbent assay.

RESULTS

The mean ages of cases and controls were 40.8 ± 9.4 and 41.5 ± 9.3 years, respectively (P = 0.5). In the case group, 81.9% and in the control group 83.7% were male (P = 0.74). The frequency of positive antinuclear antibodies and anticyclic citrullinated peptide antibodies in the serum of the two groups were not significantly different (P = 0.68 and P = 0.62, respectively). Only one antineutrophil cytoplasmic antibody-positive case (1%) was observed in the group and no anti-phospholipid immunoglobulin G positivity was observed. The frequency of rheumatoid factor (RF) was greater in case group than in the control group, although the difference was not significant (P = 0.08). The amount of RF in all 12 RF positive sera were higher than normal levels (33-37 IU/mL).

CONCLUSION

Because we failed to detect any significant relation between serum autoimmune markers and HTLV-1 infection, and because of the relatively low prevalence of autoimmune diseases, it could be concluded that healthy HTLV-1 carriers do not produce rheumatologic-related auto-antibodies more than the healthy population.

Hepatitis C virus and human T-cell lymphotropic virus type 1 co-infection: impact on liver disease, virological markers, and neurological outcomes

OBJECTIVES

Human T-cell lymphotropic virus type 1 (HTLV-1) infection is associated with neurological abnormalities, such as HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) and peripheral neuropathy (PN). Hepatitis C virus (HCV) infection is the leading cause of chronic liver disease worldwide, and causes PN in approximately 9% of patients. Because the interplay between these potentially neuropathogenic viruses in the same individual is still poorly understood, the clinical and laboratory outcomes of co-infected patients were evaluated and compared with those of controls.

METHODS

The prevalence rates of neurological and laboratory abnormalities were evaluated in HCV/HTLV-1 co-infected patients (n=50), and in subjects with single HCV (n=46) or HTLV-1 (n=150) infection.

RESULTS

A higher frequency of isolated PN was present in HCV-infected patients; this was not associated with cryoglobulinemia. No difference was found in the frequency of PN or HAM/TSP when co-infected subjects were compared to singly infected subjects. Hepatic involvement was present in HCV-infected subjects, as shown by increased levels of serum alanine aminotransferase, aspartate aminotransferase, gamma-glutamyl transferase, and bilirubin, in addition to thrombocytopenia. On the other hand, HCV/HTLV-1 co-infected individuals presented a better prognosis for hepatic involvement when compared with singly HCV-infected subjects.

CONCLUSIONS

These data suggest that HCV/HTLV-1 co-infection does not mutualistically alter the outcome with regard to neurological manifestations. Nonetheless, changes in the immunological environment induced by HTLV-1 infection could lead to a reduction in hepatic damage, even without significant HCV clearance.

Telomere Length, Proviral Load and Neurologic Impairment in HTLV-1 and HTLV-2-Infected Subjects

Short or damaged telomeres have been implicated in degenerative conditions. We hypothesized that analysis of telomere length (TL) in human T-cell lymphotropic virus (HTLV) infection and HTLV-associated neuropathy might provide clues to the etiology of HTLV-associated disease and viral dynamics. A subset of 45 human T-cell lymphotropic virus type 1 (HTLV-1), 45 human T-cell lymphotropic virus type 2 (HTLV-2), and 45 seronegative subjects was selected from the larger HTLV Outcomes Study (HOST) cohort, matched on age, sex and race/ethnicity. Telomere-to-single-copy gene (T/S) ratio (a measure of TL) and HTLV-1 and HTLV-2 proviral loads were measured in peripheral blood mononuclear cells (PBMCs) using quantitative PCR (qPCR). Vibration sensation measured by tuning fork during neurologic examinations performed as part of the HOST study allowed for an assessment of peripheral neuropathy. TL was compared between groups using t-tests, linear and logistic regression. Mean T/S ratio was 1.02 ± 0.16 in HTLV-1, 1.03 ± 0.17 in HTLV-2 and 0.99 ± 0.18 in HTLV seronegative subjects (p = 0.322). TL was not associated with HTLV-1 or -2 proviral load. Shorter TL was significantly associated with impaired vibration sense in the HTLV-2 positive group only. Overall, we found no evidence that telomere length was affected by chronic HTLV-1 and HTLV-2 infection. That TL was only associated with peripheral neuropathy in the HTLV-2-positive group is intriguing, but should be interpreted cautiously. Studies with larger sample size and telomere length measurement in lymphocyte subsets may clarify the relationship between TL and HTLV-infection.

HUMAN T-LYMPHOTROPIC VIRUS 1 (HTLV-1) AND HUMAN T-LYMPHOTROPIC VIRUS 2 (HTLV-2): GEOGRAPHICAL RESEARCH TRENDS AND COLLABORATION NETWORKS (1989-2012)

Publications are often used as a measure of research work success. Human T-lymphotropic virus (HTLV) type 1 and 2 are human retroviruses, which were discovered in the early 1980s, and it is estimated that 15-20 million people are infected worldwide. This article describes a bibliometric review and a coauthorship network analysis of literature on HTLV indexed in PubMed in a 24-year period. A total of 7,564 documents were retrieved, showing a decrease in the number of documents from 1996 to 2007. HTLV manuscripts were published in 1,074 journals. Japan and USA were the countries with the highest contribution in this field (61%) followed by France (8%). Production ranking changed when the number of publications was normalized by population (Dominican Republic and Japan), by gross domestic product (Guinea-Bissau and Gambia), and by gross national income per capita (Brazil and Japan). The present study has shed light on some of the defining features of scientific collaboration performed by HTLV research community, such as the existence of core researchers responsible for articulating the development of research in the area, facilitating wider collaborative relationships and the integration of new authors in the research groups.

Correlation between clinical symptoms and peripheral immune response in HAM/TSP

HTLV-1 infects principally CD4+ T cells that are the main reservoirs of the virus in vivo, which play an important role in the immunological response. Most of the infected patients are asymptomatic. However, 2-3% of patients will develop HAM/TSP or Adult T lymphoma. HAM/TSP is a chronic inflammatory disease of the central nervous system, which is characterized by unremitting myelopathic symptoms. Studies have shown that cytokines levels alterations (IFN-γ and TNF-α) were associated with tissue injury in HAM/TSP. The aims of this study were to compare the gene expression of IFN-γ, IL-4 and IL-10 of asymptomatic and HAM/TSP HTLV-1 infected patients, and to correlate the gene expression with those of clinical symptoms. 28 subjects were included, 20 asymptomatic HTLV-1 and 8 with HAM/TSP. Spasticity was evaluated using the Modified Ashworth Scale and the degree of walking aid was classified on a progressive scale. The relative gene expression of IFN-γ, IL-4, and IL-10 was measured by Real-Time PCR. Results showed high gene expression of IFN-γ for all patients, but it was higher among HAM/TSP. A significant correlation was observed between IFN-γ gene expression and the degree of walking aid, and IFN-γ gene expression was higher among wheelchair users compared to non-wheelchair users. No association was found with IL-4 and IL-10. These findings indicate that HAM/TSP patients express higher amounts of IFN-γ than asymptomatic patients, and more importantly, the expression of this cytokine was strongly correlated with the need of walking aid.

Human T-lymphotropic virus and transfusion safety: does one size fit all?

Human T-cell leukemia viruses (HTLV-1 and HTLV-2) are associated with a variety of human diseases, including some severe ones. Transfusion transmission of HTLV through cellular blood components is undeniable. HTLV screening of blood donations became mandatory in different countries to improve the safety of blood supplies. In Japan and Europe, most HTLV-infected donors are HTLV-1 positive, whereas in the United States a higher prevalence of HTLV-2 is reported. Many industrialized countries have also introduced universal leukoreduction of blood components, and pathogen inactivation technologies might be another effective preventive strategy, especially if and when generalized to all blood cellular products. Considering all measures available to minimize HTLV blood transmission, the question is what would be the most suitable and cost-effective strategy to ensure a high level of blood safety regarding these viruses, considering that there is no solution that can be deemed optimal for all countries.

Relevance of retrovirus quantification in cerebrospinal fluid for neurologic diagnosis

Different human retroviruses, such as Human Immunodeficiency Virus (HIV) and Human T-cell Lymphotropic Virus (HTLV), can cause neurologic infection. However, a definitive diagnosis may be hampered by several factors. Quantification of the viral or proviral load in cerebrospinal fluid (CSF) may be helpful in the diagnosis of nervous system disorders due to retroviral infection and may influence the treatment approach. The present work discusses retrovirus infection and neurologic impairment, as well as the usefulness of the determination of the HIV and HTLV proviral or viral load in cerebrospinal fluid in cases of neurologic disorder, in light of recent advances in this field. This study also discusses the different molecular techniques for quantifying the proviral load (real-time quantitative PCR, droplet digital PCR, and semi-nested real-time reverse transcription PCR) that are currently available.

Neurological Manifestations in Human T-Cell Lymphotropic Virus Type 1 (HTLV-1)-Infected Individuals Without HTLV-1-Associated Myelopathy/Tropical Spastic Paraparesis: A Longitudinal Cohort Study

BACKGROUND

Human T-cell lymphotropic virus type 1 (HTLV-1) is the agent of HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP), observed in up to 5% of infected individuals. Despite low prevalence, many HTLV-1-infected patients who do not fulfill criteria for HAM/TSP present with neurological complaints related to sensory, motor, urinary, or autonomic manifestations. The aim of this study was to determine the incidence of neurologic manifestations and risk factors associated with these outcomes.

METHODS

The incidence of HAM/TSP and new signs and neurologic symptoms were computed in a group of patients enrolled in a cohort study.

RESULTS

Of 414 subjects, 76 had definite HAM/TSP, 87 had possible or probable HAM/TSP, and 251 subjects had no neurologic manifestation and were selected for analysis. Definite HAM/TSP developed in 5 (1.47%) patients. Follow-up of at least 3 years was achieved in 51% of patients. The incidence rate was computed in 1000 person-years (206 for hand numbness, 187 for feet numbness, 130 for nocturia, and 127 for urgency). Average incidence rate in neurological exam was 76 for leg hyperreflexia, 53 for leg weakness, and 37 for Babinski sign. In the applied Expanded Disability Status Scale, the incidence rate of worsening 1 point was 134 per 1000 person-years. Kaplan-Meier curves stratified by sex and proviral load showed that females and patients with proviral load >50,000 copies/10(6) peripheral blood mononuclear cells had a higher risk of progression.

CONCLUSIONS

Development of neurological symptoms or signs occurred in up to 30% of asymptomatic subjects during 8 years of follow-up.

[Recurrent facial palsy revealing Human T-lymphotropic virus type 1 (HTLV-1) infection]

INTRODUCTION

Neurological involvement of Human T-lymphotropic virus type 1 (HTLV-1) mainly results in myelopathy (tropical spastic paraparesis). However, cranial nerve impairment, including facial nerve damage, is rare in patients with HTLV-1 infection.

OBSERVATION

We report the case of a patient, originally from Caribbean islands, who developed recurrent bilateral facial palsy (six recurrences during the 7-year follow-up). Both blood and cerebrospinal fluid serologies were positive for HTLV-1. The diagnosis of recurring bilateral facial palsy revealing HTLV-1 infection was made.

CONCLUSION

Our case report underscores that HTLV-1 infection should be considered in patients, coming from endemic areas (Caribbean islands, South America, Japan and Africa), who exhibit recurrent bilateral facial palsy. Our data therefore indicate that HTLV-1 serology should be routinely performed in these patients.

Clonality of HTLV-2 in natural infection

Human T-lymphotropic virus type 1 (HTLV-1) and type 2 (HTLV-2) both cause lifelong persistent infections, but differ in their clinical outcomes. HTLV-1 infection causes a chronic or acute T-lymphocytic malignancy in up to 5% of infected individuals whereas HTLV-2 has not been unequivocally linked to a T-cell malignancy. Virus-driven clonal proliferation of infected cells both in vitro and in vivo has been demonstrated in HTLV-1 infection. However, T-cell clonality in HTLV-2 infection has not been rigorously characterized. In this study we used a high-throughput approach in conjunction with flow cytometric sorting to identify and quantify HTLV-2-infected T-cell clones in 28 individuals with natural infection. We show that while genome-wide integration site preferences in vivo were similar to those found in HTLV-1 infection, expansion of HTLV-2-infected clones did not demonstrate the same significant association with the genomic environment of the integrated provirus. The proviral load in HTLV-2 is almost confined to CD8⁺ T-cells and is composed of a small number of often highly expanded clones. The HTLV-2 load correlated significantly with the degree of dispersion of the clone frequency distribution, which was highly stable over ∼8 years. These results suggest that there are significant differences in the selection forces that control the clonal expansion of virus-infected cells in HTLV-1 and HTLV-2 infection. In addition, our data demonstrate that strong virus-driven proliferation per se does not predispose to malignant transformation in oncoretroviral infections.

The two human retroviruses HTLV-1 and HTLV-2 are similar in their structure, replication cycle and the manner through which they spread between and within individuals. They differ in their preferred host T-cell type and in their possible clinical outcomes. HTLV-2 has not been linked with a specific disease, whereas HTLV-1 infection can cause leukemia and profound neuropathology. It is well established that HTLV-1-infected cells undergo clonal expansion in infected individuals, but little is known about clonality in HTLV-2 infection. In this work, we demonstrate that the extent of HTLV-2-infected cell expansion significantly exceeds that of HTLV-1-infected cells in healthy carriers, approximating instead to that observed in patients with HTLV-1-associated leukemia. Furthermore, we show that HTLV-2 characteristically resides in a small number of expanded clones that persist over time, and that the degree of oligoclonality significantly correlates with viral burden in HTLV-2-infected individuals. These results highlight the distinction between in vivo clonal proliferation and malignant transformation, and suggest that the infected cell type may be a more important determinant of clinical outcome in retroviral infections.

Soluble IL-2 receptor and beta-2 microglobulin as possible serologic markers of neurologic disease in HTLV-1 infection

The human T-cell leukemia virus (HTLV-1) is the causative agent of a variety of neurologic diseases, including HTLV-1 Associated Myelopathy (HAM/TSP) and overactive bladder. Investigation of immune markers such as soluble interleukin-2 receptor (sIL-2R) and beta-2 microglobulin (B2M) has shown some promising results in distinguishing patients with neurologic disease from those with carrier status. The objective of the present study was to determine if plasma levels of sIL-2R and B2M are markers of neurologic disease in individuals infected with HTLV-1. The present study was divided into two parts. A cross-sectional study and a nested case control study. In the cross-sectional study, HAM/TSP patients had higher plasma levels of B2M and sIL-2R than patients with overactive bladder and HTLV-1 carriers (P < 0.01 for all comparisons). For the nested case control study, the sIL-2 receptor test was able to distinguish patients with HAM/TSP from patients in the combined group of carriers and patients with overactive bladder with a sensitivity of 75.8% and false positive rate of 25.4%. Plasma levels of these markers did not change with the development of HAM/TSP and overactive bladder in HTLV-1 carrier patients. The present study has shown the importance of sIL-2 receptor in helping identifying HAM/TSP. However, the levels of these makers did not change significantly with the development of neurologic disease.

Immunopathogenesis and neurological manifestations associated to HTLV-1 infection

The human T lymphotropic virus type-1 (HTLV-1) was the first human retrovirus identified. The virus is transmitted through sexual intercourse, blood transfusion, sharing of contaminated needles or syringes and from mother to child, mainly through breastfeeding. In addition to the well-known association between HTLV-1 and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP), several diseases and neurologic manifestations have been associated with the virus. This review was conducted through a PubMed search of the terms HTLV-1, immune response and neurological diseases. Emphasis was given to the most recent data regarding pathogenesis and clinical manifestations of HTLV-1 infection. The aim of the review is to analyze the immune response and the variety of neurological manifestations associated to HTLV-1 infection. A total of 102 articles were reviewed. The literature shows that a large percentage of HTLV-1 infected individuals have others neurological symptoms than HAM/TSP. Increased understanding of these numerous others clinical manifestations associated to the virus than adult T cell leukemia/lymphoma (ATLL) and HAM/TSP has challenged the view that HTLV-1 is a low morbidity infection.

Testing the vestibular evoked myogenic potential (VEMP) to identify subclinical neurological alterations in different phases of human T-lymphotropic virus type 1 infection

BACKGROUND CONTEXT

The diagnosis of human T-lymphotropic virus type 1 (HTLV-1)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is based on clinical signs and the confirmation of HTLV-1 infection in the central nervous system. Electrophysiological tests may facilitate an earlier diagnosis of spinal cord involvement. Vestibular evoked myogenic potential (VEMP) testing evaluates the vestibulospinal tract, which is correlated with the motor tract; the target of damage by HAM/TSP.

PURPOSE

This study examines the subclinical neurological alterations related to HTLV-1 infection in individuals with asymptomatic HTLV-1 infections, possible HAM/TSP, and confirmed HAM/TSP.

STUDY DESIGN

Vestibular evoked myogenic potential testing was performed at the beginning of the study and repeated every 6 months for 18 months. Ninety volunteers were selected for the study: 30 were HTLV-1 seronegative (the control group) and 60 were HTLV-1 seropositive (of these, 18 were asymptomatic, 25 had possible HAM/TSP, and 17 had confirmed HAM/TSP). The VEMP response was classified as normal or abnormal (latency prolongation or no response). A change in the VEMP response from normal to abnormal was the event of interest. To perform a survival analysis, the subjects with normal VEMP responses at the first assessment were selected.

METHODS

The results were analyzed blindly. Vestibular evoked myogenic potential was measured using short tone bursts as acoustic stimuli (1 kHz, 118 dBHL, a rise-fall of 1 millisecond, and a plateau of 2 milliseconds). The stimulation rate was 5 Hz, and the analysis time for each response was 60 milliseconds; each trial averaged 200 responses.

RESULTS

The mean age of the subjects in the control group was 38 ± 11 years (median 35), and 13 (43%) were men. In the study group, the mean age was 51 ± 12 years (median 53), and 12 (20%) were men. An analysis of the survival curve indicated that the median time for a change in VEMP response from normal to abnormal was 18 months, which is in agreement with the slow progression of HTLV-1-associated neurologic disease. The survival analysis showed that the change in VEMP response was significantly different between the asymptomatic and HAM/TSP groups (p=.02).

CONCLUSIONS

Vestibular evoked myogenic potential testing was useful for monitoring the development of HAM/TSP in HTLV-1-infected individuals.

Neurological symptoms and signs in HTLV-1 patients with overactive bladder syndrome

OBJECTIVE

To compare neurological symptoms and signs in HTLV-1 asymptomatic carriers and HTLV-1 patients with overactive bladder (OB) syndrome.

METHODS

We studied 102 HTLV-1 positive individuals without HAM/TSP (HTLV-1 associated myelopathy/tropical spastic paraparesis) divided into two groups according to the presence or absence of OB syndrome. Clinical interview, neurological exam and proviral load was performed in all patients.

RESULTS AND CONCLUSIONS

Individuals with OB were more commonly female (84.3 vs. 60.8% of asymptomatics, p=0.01). The prevalence of neurological complaints was higher in OB group, especially hand or foot numbness and arm or leg weakness. There was no difference between the groups in neurological strength and reflexes. Weakness complaint remained strongly associated with OB in multivariate logistic regression analysis adjusting for sex and age [adjusted odds ratio and 95%CI 3.59 (1.45-8.88) in arms and 6.68 (2.63-16.93) in legs]. Proviral load was also different between the two groups with higher level on OB individuals.

Pathways of cell-cell transmission of HTLV-1

The deltaretroviruses human T cell lymphotropic virus type 1 (HTLV-1) and human T cell lymphotropic virus type 2 (HTLV-2) have long been believed to differ from retroviruses in other genera by their mode of transmission. While other retroviruses were thought to primarily spread by producing cell-free particles that diffuse through extracellular fluids prior to binding to and infecting target cells, HTLV-1 and HTLV-2 were believed to transmit the virus solely by cell–cell interactions. This difference in transmission was believed to reflect the fact that, relative to other retroviruses, the cell-free virions produced by HTLV-infected cells are very poorly infectious. Since HTLV-1 and HTLV-2 are primarily found in T cells in the peripheral blood, spread of these viruses was believed to occur between infected and uninfected, T cells, although little was known about the cellular and viral proteins involved in this interaction. Recent studies have revealed that the method of transmission of HTLV is not unique: other retroviruses including human immunodeficiency virus (HIV) are also transmitted from cell-to-cell, and this method is dramatically more efficient than cell-free transmission. Moreover, cell–cell transmission of HTLV-1, as well as HIV, can occur following interactions between dendritic cells and T cells, as well as between T cells. Conversely, other studies have shown that cell-free HTLV-1 is not as poorly infectious as previously thought, since it is capable of infecting certain cell types. Here we summarize the recent insights about the mechanisms of cell–cell transmission of HTLV-1 and other retroviruses. We also review in vitro and in vivo studies of infection and discuss how these finding may relate to the spread of HTLV-1 between individuals.

Infectious neuropathies

PURPOSE OF REVIEW

The purpose of this review is to address bacterial, viral, and other infectious causes of neuropathy or neuronopathy, with an emphasis on clinical manifestations and treatment.

RECENT FINDINGS

Most infectious neuropathies have been well described for some time and treatments are well established. An exception is HIV-associated distal symmetric polyneuropathy, which is an area of active research. Current work in this area focuses on epidemiology, risk factors, and underlying mechanisms.

SUMMARY

Infectious diseases are an important part of the differential diagnosis of peripheral nerve disorders because they are among the most amenable to treatment. However, diagnosis of infectious peripheral neuropathy may be challenging because of variability in a number of factors, including the pattern of deficits, geographic distribution of pathogens, length of time from the onset of infection to the development of neuropathy, and mechanism of nerve injury.

Relevance of neuroimaging in the diagnosis and management of tropical neurologic disorders

The development in neuroimaging techniques has revolutionized the way neurology is practiced, including neurologic disorders in tropics. Some diseases occur exclusively, whereas some are more common in tropical regions. However, some are becoming increasingly prevalent in the developed world too, as a result of patterns of human migration and globalization. It is imperative to learn about the role of imaging in tropical neurology, which might assist early diagnosis and treatment and also add to the existing knowledge. Infections are more common in the tropics and require special attention in view of their potential treatability.

Detrusor Arreflexia as an End Stage of Neurogenic Bladder in HAM/TSP?

The HTLV-1 virus is a known agent involved in the development of HAM/TSP. Past studies have typically observed patients with autonomic dysfunction consisting of detrusor overactivity and detrusor-sphincter dyssynergia, with the occasional observation of underactive detrusor or detrusor arreflexia. However, studies have not yet evaluated the progression of neurogenic bladder over time. In this paper, we describe a HAM/TSP patient with the initial development of overactive detrusor, and subsequent development of detrusor arreflexia. Given a paucity of studies characterizing the effects of HTLV-1 on the autonomic nervous system, particularly aspects controlling continence, this patient's clinical course may represent one type of end point for patients with HAM/TSP and neurogenic bladder. Further cohort or case-series studies, with particular emphasis on the progression of neurogenic bladder, are needed to evaluate the significance of this described case in relation to typical disease progression patterns.

HTLV-2b among HIV type 1-coinfected injecting drug users in Spain

Human T cell lymphotropic virus type 2 (HTLV-2) infection is endemic in the American Indian population and Pygmy tribes in Africa. Nevertheless, HTLV-2 infection has been predominantly detected in U.S. and European injecting drug users (IDU). Noteworthy is that the HTLV-2a subtype is the main circulating variant in North America and Eastern Europe whereas the HTLV-2b subtype is mainly found in Western Europe, particularly in Italy and Spain where coinfection with HIV-1 is frequent. Twelve Spanish subjects infected with HTLV-2 were recruited for the study. All of them were IDUs coinfected with HIV-1. Molecular epidemiology was done by sequencing the LTR, env, and tax regions and by generating phylogenetic trees. The present study showed that all the sequences belonged to the HTLV-2b subtype and were closely related to other Spanish and Portuguese reported sequences, clearly differentiated from those belonging to the HTLV-2a subtype from Eastern Europe. Therefore, infection with HTLV-2b remains prevalent in Spain based on previous studies.

Clinical manifestations in individuals with recent diagnosis of HTLV type I infection

BACKGROUND

Human T-lymphotropic virus type 1 (HTLV-1) is known to cause HTLV-associated myelopathy (HAM)/tropical spastic paraparesis and adult T cell leukemia. A growing body of evidence links HTLV-1 infection with an increasing spectrum of disease, including uveitis, periodontal disease, arthropathy, sicca syndrome, and neurologic deficits.

OBJECTIVES

Despite recent findings, the natural history of HTLV-1 infection remains poorly defined. This study was designed to better characterize initial clinical and neurological findings in individuals diagnosed with HTLV-1 infection.

STUDY DESIGN

We conducted a cross-sectional study of 71 individuals recently diagnosed with HTLV-1 and 71 uninfected age- and sex-matched blood donors in Salvador, Brazil. Subjects were administered a standardized questionnaire and underwent physical exam.

RESULTS

HTLV-1 infected subjects were significantly more likely than controls to report complaints of hand and foot numbness (OR=5.3; 95% CI: 1.8-15.3; p=0.002 and OR=4.0; 95% CI: 1.3-12; p=0.013 respectively), difficulty running (OR=4.0; 95% CI: 1.1-14.2; p=0.032), nocturia (OR=5.0; 95% CI: 1.1-22.8; p=0.038), arthralgia (OR=3.3; 95% CI: 1.4-7.7; p=0.006), and photophobia (OR=3.3; 95% CI: 1.4-7.7; p=0.006).

CONCLUSIONS

Neurologic, ocular and rheumatologic complaints may be the first manifestations of HTLV-1 infection. Therefore, all patients presenting with initial diagnosis should be rigorously screened for these symptoms.

Prevalence of HTLV-1/2 infections in Spain: A cross-sectional hospital-based survey

The presence of antibodies to human T-lymphotropic virus (HTLV) types 1 and 2 was examined in 5742 sera belonging to consecutive adult outpatients attended during June 2008 at 13 different hospitals across Spain. Overall, 58.8% were female. Foreigners represented 8% of the study population. Seven individuals were seropositive for HTLV-2 (overall prevalence 0.12%). No cases of HTLV-1 infection were found. All HTLV-2(+) subjects were Spanish natives, of whom six were coinfected with HIV-1 and five with hepatitis C virus (HCV). Moreover, all but one of the HTLV-2(+) subjects had been intravenous drug users. In summary, this cross-sectional survey suggests that the rate of HTLV infection in Spain is low, and is mostly represented by HTLV-2. Infected individuals are generally Spanish natives with a prior history of intravenous drug use and are coinfected with HIV-1 and/or HCV.

HTLV infection and its implication in gynaecology and obstetrics

INTRODUCTION

Worldwide, 20-30 million people are estimated to be infected with HTLV. HTLV-1 is endemic in Western Africa and Southern Japan, whereas HTLV-2 is considered to be spread among native American people.

MATERIALS AND METHODS

The impact of HTLV in gynaecology and obstetrics is being reviewed. Search strategy and selection criteria for identifying relevant data were performed by searching Medline, Current Contents, Web of Science, Embase and references from relevant articles. English and German gynaecological and infectious diseases textbooks as well as national and international guidelines and recommendations were also reviewed.

RESULTS

Transmission may occur by sexual intercourse or cellular blood products. Although materno-fetal transmission is debated, transmission through maternal breast milk has been confirmed. An HTLV-infection can lead to adult T-cell leukaemia (ATL) or cumulative opportunistic and neurological disorders that can occur with varying degrees of severity. Diagnosis can be done by antibody detection via the use of ELISA and western blot analysis as well as PCR diagnosis.

CONCLUSION

Due to inadequate treatment options and the lack of an effective vaccination, prevention is currently only possible by restricting transmission, including the usage of condoms during sexual intercourse or avoiding breastfeeding in HTLV-seropositive mothers. If, due to socio-economic reasons, breastfeeding cannot be avoided, short-term breastfeeding for a maximum of up to 6 months is suggested.