Degenerate specificity of HTLV-1-specific CD8+ T cells during viral replication in patients with HTLV-1-associated myelopathy (HAM/TSP)

Human T-lymphotropic virus type 1 (HTLV-1)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is an inflammatory neurologic disease caused by HTLV-1 infection, in which HTLV-1-infected CD4(+) T cells and HTLV-1-specific CD8(+) T cells may play a role in the disease pathogenesis. Patients with HAM/TSP have high proviral loads despite vigorous virus-specific CD8(+) T-cell responses; however, it is unknown whether the T cells are efficient in eliminating the virus in vivo. To define the dynamics of HTLV-1-specific CD8(+) T-cell responses, we investigated longitudinal alterations in HTLV-1 proviral load, amino acid changes in an immunodominant viral epitope, frequency of HTLV-1-specific T cells, and degeneracy of T-cell recognition in patients with HAM/TSP. We showed that the frequency and the degeneracy of the HTLV-1-specific CD8(+) T cells correlated well with proviral load in the longitudinal study. The proviral load was much higher in a patient with low degeneracy of HTLV-1-specific T cells compared to that in a patient with comparable frequency but higher degeneracy of the T cells. Furthermore, in a larger number of patients divided into 2 groups by the proviral load, those with high proviral load had lower degeneracy of T-cell recognition than those with low proviral load. Sequencing analysis revealed that epitope mutations were remarkably increased in a patient when the frequency and the degeneracy were at the lowest. These data suggest that HTLV-1-specific CD8(+) T cells with degenerate specificity are increased during viral replication and control the viral infection.     

Genetic markers on the HTLV-1 p12I protein sequences from Brazilian HAM/TSP patients and asymptomatic HTLV-1 carrier isolates

The human T cell leukemia/lymphotropic virus type-1 (HTLV-1) genome has approximately 9 kb and contains the pX region that codes for regulatory and accessory proteins. The pX ORF-I encodes for the p12 protein, a 99 aa peptide, which presents several functional putative domains, such as leucine zipper motifs, SH3- binding motifs, and a dileucine motif, p12I. Also, a rare p12IK88 allele was found mainly in HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) patients, suggesting it is a marker of pathogenesis, although recent studies showed p12IK in asymptomatic HTLV-1 carriers. To extend the observations on p12I motifs, we sequenced 26 p12I from HAM/TSP patients and asymptomatic HTLV-1 carriers. Amino acid analysis of 48 p12I motifs demonstrated the presence of several alleles, but the allelic variation, including p12IK, was not prevalent in HAM/TSP isolates. Nonetheless, some genetic markers were recognized in association with isolates from HTLV-1a subgroup B and Brazilian HTLV-1aA strains.     

Proviral load and the balance of serum cytocines in HTLV-1-asymptomatic infection and in HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP)

This study compared the proviral load and the plasma cytokine profiles (interleukin-IL-2, IL-4, IL-6, IL-10, TNF-α, IFN-γ) in 87 HTLV-1-infected individuals, including 28 with HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP), 32 with possible pHAM/TSP and 27 asymptomatic carriers (AC). The control group was composed by 21 HTLV-1-seronegative individuals. Our finding demonstrated that HAM/TSP group presented higher proviral load as compared to all other HTLV-1 groups (p < 0.0001). The HAM/TSP group showed higher serum concentration of IL-6 (p = 0.0009) as compared to all other groups. Moreover, higher serum concentration of IFN-γ (p = 0.0118) and IL-4 (p = 0.0166) were observed in HAM/TSP group as compared to the healthy controls. Additionally, the HAM/TSP group also showed higher serum concentration of TNF-α (p = 0.0239) and IFN-γ (p = 0.0118) as compared to AC. No differences in the serum concentration of IL-2 and IL-10 were observed among the groups. The analysis of cytokine balance demonstrated that HAM/TSP presented higher pro-inflammatory profile with enhanced IFN-γ/IL-10 and IFN-γ/IL-4 ratio as compared to AC and pHAM/TSP. Further analysis pointed out to a positive correlation between the IFN-γ response and the proviral load in AC. Conversely, a negative association between TNF-α and IL-2 with the proviral load was the hallmark of HAM/TSP group. These findings suggested that the proviral load and the pro-inflammatory cytokine profile may be independent events in the peripheral blood of HAM/TSP individuals. The knowledge about the existence of individual virological/immunological behavior upon HTLV-1 infection, may guide to the establishment of more effective therapeutic interventions.     

Cyclosporine for the Treatment of HTLV-1-Induced HAM/TSP: An Experience from a Case Report

HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) remains a challenging disease. Treatment options are scarce, and their safety and efficacy are currently a matter of concern.We present a case report describing our experience using cyclosporine in a patient with early HAM/TSP who started with a gait disturbance at Vall d’Hebron University Hospital (Barcelona) from August 2012 to October 2013. After 62 weeks of treatment, clinical improvement was observed and proviral load diminished. No safety concerns were observed.Cyclosporine seems to be effective in new-onset HAM/TSP or in chronic HAM/TSP that develops a relapse. However, the duration and safety profile of this steroid-sparing therapy remain unknown and should be further investigated.     

Tropical spastic paraparesis/HTLV-1-associated myelopathy (TSP/HAM): treatment with an anabolic steroid danazol.

Tropical spastic paraparesis or HTLV-I-associated myelopathy is a progressive spastic disorder associated with the human T-lymphotropic virus type I. Some cases have responded to prednisone. Danazol is an attenuated androgen with minimal virilizing effects. It is used in the treatment of endometriosis and various autoimmune hematologic diseases shown to be responsive to prednisone. Because danazol is anabolic, useful in prednisone-responsive diseases, and less toxic than prednisone, we gave danazol to 6 patients with TSP and 1 with HIV, HTLV-I-associated myelopathy. Five patients had a favorable response. Two became ambulatory after having been confined to a wheelchair. Three were able to ambulate greater distances (in walkers) than prior to danazol. Three had noticeable decreases in spasticity. Urinary incontinence resolved in two. Physical therapy was variably employed in all except one patient. Two patients who had not responded to physical therapy responded to physical therapy and danazol. One patient did not tolerate danazol and one patient did not improve. Toxicities noted were mild elevations in liver enzymes in 4 patients; these responded to a decrease in dose of danazol; amenorrhea in one and mild fluid retention in one. We conclude that danazol is a useful agent in the management of TSP.     

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

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

Bronchopneumonopathy in HTLV-1 associated myelopathy (HAM) and non-HAM HTLV-1 carriers]

Human T-cell leukemia virus type 1 (HTLV-1) causes not only adult T-cell leukemia (ATL), but also HTLV-1 associated myelopathy, a recently described slowly progressive spastic paraparesis, in its carrier state. Pulmonary involvement has been reported in HAM patients. Based on bronchoalveolar lavage or histological examination, the pulmonary involvement has been characterized by accumulation of T-cells, especially activated T-cells, in the lung. We reviewed our data on pulmonary involvement in HAM, which suggested that the characteristic pulmonary involvement observed in HAM was not restricted to HAM patients, but was also observed in non-HAM HTLV-1 carriers. Based on the data, we report that HAM is a systemic disease and that HTLV-1 causes characteristic pulmonary involvement, which we termed HTLV-1 associated bronchopneumonopathy (HAB).     

T CD4+ cells count among patients co-infected with human immunodeficiency virus type 1 (HIV-1) and human T-cell leukemia virus type 1 (HTLV-1): high prevalence of tropical spastic paraparesis/HTLV-1-associated myelopathy (TSP/HAM)

INTRODUCTION: HIV positive patients co-infected with HTLV-1 may have an increase in their T CD4+ cell counts, thus rendering this parameter useless as an AIDS-defining event. OBJECTIVE: To study the effects induced by the co-infection of HIV-1 and HTLV-1 upon CD4+ cells. MATERIAL AND METHODS: Since 1997, our group has been following a cohort of HTLV-1-infected patients, in order to study the interaction of HTLV-1 with HIV and/or with hepatitis C virus (HCV), as well as HTLV-1-only infected asymptomatic carriers and those with tropical spastic paraparesis/HTLV-1 associated myelopathy (TSP/HAM). One hundred and fifty HTLV-1-infected subjects have been referred to our clinic at the Institute of Infectious Diseases "Emílio Ribas", S?o Paulo. Twenty-seven of them were also infected with HIV-1 and HTLV-1-infection using two ELISAs and confirmed and typed by Western Blot (WB) or polymerase chain reaction (PCR). All subjects were evaluated by two neurologists, blinded to the patient's HTLV status, and the TSP/HAM diagnostic was based on the World Health Organization (WHO) classification. AIDS-defining events were in accordance with the Centers for Disease Control (CDC) classification of 1988. The first T CD4+ cells count available before starting anti-retroviral therapy are shown compared to the HIV-1-infected subjects at the moment of AIDS defining event. RESULTS: A total of 27 HIV-1/HTLV-1 co-infected subjects were identified in this cohort; 15 already had AIDS and 12 remained free of AIDS. The median of T CD4+ cell counts was 189 (98-688) cells/mm(3) and 89 (53-196) cells/mm(3) for co-infected subjects who had an AIDS-defining event, and HIV-only infected individuals, respectively (p = 0.036). Eight of 27 co-infected subjects (30%) were diagnosed as having a TSP/HAM simile diagnosis, and three of them had opportunistic infections but high T CD4+ cell counts at the time of their AIDS- defining event. DISCUSSION: Our results indicate that higher T CD4+ cells count among HIV-1/HTLV-1-coinfected subjects was found in 12% of the patients who presented an AIDS-defining event. These subjects also showed a TSP/HAM simile picture when it was the first manifestation of disease; this incidence is 20 times higher than that for HTLV-1-only infected subjects in endemic areas.     

High frequencies of Th1-type CD4(+) T cells specific to HTLV-1 Env and Tax proteins in patients with HTLV-1-associated myelopathy/tropical spastic paraparesis

CD4(+) T cells are critical for inducing and maintaining efficient humoral and cellular immune responses to pathogens. The CD4(+) T-cell response in human T-lymphotropic virus 1 (HTLV-1) infection has not been studied in detail. However, CD4(+) T cells have been shown to predominate in early lesions in HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). We present direct estimates of HTLV-1 Env- and Tax-specific CD4(+) T-cell frequencies in patients infected with HTLV-1. We first showed that there was a strong bias toward the Th1 phenotype in these HTLV-1-specific CD4(+) T cells in patients with HAM/TSP. We then demonstrated significantly higher frequencies of HTLV-1-specific Th1-type CD4(+) T cells in HAM/TSP patients than in asymptomatic HTLV-1 carriers. The majority of these HTLV-1-specific CD4(+) T cells did not express HTLV-1 Tax and were therefore unlikely to be infected by HTLV-1. High frequencies of activated HTLV-1-specific CD4(+) T cells of the Th1 phenotype might contribute to the initiation or pathogenesis of HAM/TSP and other HTLV-1-associated inflammatory diseases.     

Common human T cell leukemia virus type 1 (HTLV-1) integration sites in cerebrospinal fluid and blood lymphocytes of patients with HTLV-1-associated myelopathy/tropical spastic paraparesis indicate that HTLV-1 crosses the blood-brain barrier via clonal HTLV-1-infected cells

In the spinal cord of patients with human T cell leukemia virus type 1 (HTLV-1)-associated myelopathy/tropical spastic paraparesis (HAM/TSP), infiltrating CD4(+) lymphocytes seem to be the major reservoir for the virus. Little, however, is known about the mechanisms by which HTLV-1 crosses the blood-brain barrier. An oligoclonal proliferation of HTLV-1-infected CD4 lymphoid T cells is present in the peripheral blood of all HTLV-1-infected individuals. Here, such oligoclonal distribution of HTLV-1-infected cells is evidenced in the cerebrospinal fluid (CSF) derived from 5 patients with HAM/TSP. Furthermore, clonal populations of HTLV-1-infected lymphocytes sharing the same HTLV-1 proviral flanking sequences (i.e. , integration sites in the cellular DNA), and thus derived from a single HTLV-1-infected progenitor, were found, for a given patient, in both the CSF and the peripheral blood. These data demonstrate that HTLV-1 crosses the blood-brain barrier by migration of HTLV-1-infected lymphocytes in vivo.     

Safety of long-term treatment of HAM/TSP patients with valproic acid

HTLV-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is a neurodegenerative disease of the central nervous system induced by human T-lymphotropic virus type 1. As a potential therapeutic approach, we previously suggested reducing the proviral load by modulating lysine deacetylase activity using valproic acid (VPA) and exposing virus-positive cells to the host immune response. We conducted a single-center, 2-year, open-label trial, with 19 HAM/TSP volunteers treated with oral VPA. Proviral load, CD38/HLA-DR expression, and CD8(+) lysis efficiency were not significantly affected by VPA. Mean scores of HAM/TSP disability did not differ between baseline and final visit. Walking Time Test increased significantly (> 20%) in 3 patients and was in keeping with minor VPA side effects (drowsiness and tremor). Walking Time Test improved rapidly after VPA discontinuation. We conclude that long-term treatment with VPA is safe in HAM/TSP.     

Infiltration of the lower respiratory tract by helper/inducer T lymphocytes in HTLV-1-associated adult T-cell leukemia/lymphoma.

The human T-cell lymphotropic virus type 1 (HTLV-1) is the causative agent of adult T-cell leukemia/lymphoma (ATLL), a disorder in which peripheral blood and multiple organs are infiltrated by malignantly transformed T lymphocytes. We investigated the nature of pulmonary disease in a patient with serologic evidence of HTLV-1 infection. In this case, endobronchial biopsy specimens showed infiltration of the bronchial mucosa by pleomorphic cells exhibiting a high degree of nuclear irregularity. These cells were morphologically identical in appearance to malignant cells found in peripheral blood and infiltrating the dermis, expressed the OKT4/Leu3 phenotype and the receptor for interleukin 2, and, by analogy to gene rearrangement studies on leukemic blood cells, were monoclonal in origin. However, in situ hybridization of endobronchial biopsy specimens with full-length HTLV-1 probes failed to detect retroviral RNA or proviral DNA. These studies indicate that T lymphocytic involvement of the lower respiratory tract in HTLV-1-associated ATLL is characterized by expression of a malignant phenotype despite the inability to document actual cellular infection with this retrovirus by a molecular hybridization technique.     

Dual cytoplasmic and nuclear localization of HTLV-1-encoded HBZ protein is a unique feature of adult T-cell leukemia

Adult T-cell leukemia-lymphoma (ATL), is a highly malignant T-cell neoplasm caused by human T-cell leukemia virus type 1 (HTLV-1), characterized by poor prognosis. Two viral proteins, Tax-1 and HTLV-1 basic-zipper factor (HBZ) play important roles in the pathogenesis of ATL. While Tax-1 can be found in both the cytoplasm and nucleus of HTLV-1 infected patients, HBZ is exclusively localized in the cytoplasm of HTLV-1 asymptomatic carriers and in patients with the chronic neurologic disease HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP). HBZ is only localized in the nucleus of ATL cell lines, suggesting that the nuclear localization of HBZ can be a hallmark of neoplastic transformation. In order to clarify this crucial point, we investigated in detail the pattern of HBZ expression in ATL patients. We made use of our monoclonal antibody 4D4-F3, that at present is the only reported reagent, among the few described, able to detect endogenous HBZ by immunofluorescence and confocal microscopy in cells from asymptomatic carriers, HAM/TSP and ATL patients. We found that HBZ is localized both in the cytoplasm and nucleus of cells of ATL patients irrespective of their clinical status, with a strong preference for the cytoplasmic localization. Also Tax-1 is localized in both compartments. As HBZ is exclusively localized in the cytoplasm in asymptomatic carriers and in non-neoplastic pathologies, this finding shows that neoplastic transformation consequent to HTLV-1 infection is accompanied and associated with the capacity of HBZ to translocate to the nucleus, which suggests a role of cytoplasmic-to-nuclear translocation in HTLV-1- mediated oncogenesis.