Human T Cell Lymphotropic Virus Type 1 Infected Patients Research Articles

Human T-cell lymphotropic virus type 1 (HTLV-1) grip on T-cells: investigating the viral tapestry of activation

IntroductionHuman T-cell Lymphotropic virus type 1 (HTLV-1) belongs to retroviridae which is connected to two major diseases, including HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) and Adult T-cell leukemia/lymphoma (ATLL). This study aims to investigate the mRNA expressions of key proteins correlated to T-cell activation in asymptomatic carriers (ACs) HTLV-1 infected patients, shedding light on early molecular events and T-cell activation following HTLV-1 infection.Material and MethodsThe study involved 40 participants, including 20 ACs and 20 healthy subjects. Blood samples were collected, ELISA assessment for screening and confirmation with PCR for Trans-activating transcriptional regulatory protein (Tax) and HTLV-1 basic leucine zipper factor (HBZ) of the HTLV-1 were done. mRNA expressions of C-terminal Src kinase (CSK), Glycogen Synthase Kinase-3 Beta (GSK3β), Mitogen-Activated Protein Kinase 14 (MAP3K14 or NIK), Phospholipase C Gamma-1 (PLCG1), Protein Tyrosine Phosphatase non-Receptor Type 6 (PTPN6) and Mitogen-Activated Protein Kinase Kinase Kinase-7 (SLP-76) and Mitogen-Activated Protein Kinase14 (MAP3K7 or TAK1) were assayed using RT-qPCR. Statistical analyses were performed using PRISM and SPSS software.ResultsWhile there were no significant upregulation in CSK and PTPN6 in ACs compared to healthy individuals, expression levels of GSK3β, MAP3K14, PLCG1, SLP-76, and TAK1 were significantly higher in ACs compared to healthy subjects which directly contributes to T-cell activation in the HTLV-1 ACs.ConclusionHTLV-1 infection induces differential mRNA expressions in key proteins associated with T-cell activation. mRNAs related to T-cell activation showed significant upregulation compared to PTPN6 and CSK which contributed to T-cell regulation. Understanding these early molecular events in ACs may provide potential markers for disease progression and identify therapeutic targets for controlling viral replication and mitigating associated diseases. The study contributes novel insights to the limited literature on T-cell activation and HTLV-1 pathogenesis.

Postural Adjustments in HTLV-1 Infected Patients during a Self-Initiated Perturbation.

Human T-cell lymphotropic virus type 1 (HTLV-1) infection can be associated with tropical spastic paraparesis (TSP/HAM), which causes neurological myelopathy and sensory and muscle tone alterations, leading to gait and balance impairments. Once trunk perturbation is predicted, the motor control system uses anticipatory and compensatory mechanisms to maintain balance by recruiting postural muscles and displacement of the body's center of mass. Twenty-six participants (control or infected) had lower limb muscle onset and center of pressure (COP) displacements assessed prior to perturbation and throughout the entire movement. Semitendinosus (ST) showed delayed onset in the infected group compared to the control group. The percentage of trials with detectable anticipatory postural adjustment was also lower in infected groups in the tibialis anterior and ST. In addition, COP displacement in the infected group was delayed, had a smaller amplitude, and took longer to reach the maximum displacement. HTLV-1 infected patients have less efficient anticipatory adjustments and greater difficulty recovering their postural control during the compensatory phase. Clinical assessment of this population should consider postural stability during rehabilitation programs.

Evaluation of antioxidant status and oxidative stress markers in HTLV-1 infected individuals: correlation with the severity of virus-induced complications.

Introduction. Human T-cell lymphotropic virus type 1 (HTLV-1), a well-known member of the retroviridae family, potentially causes serious outcomes including adult T-cell leukaemia/lymphoma (ATLL) and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM-TSP). Oxidative stress plays a key role in progression and clinical exacerbation of several chronic infections. We have previously shown a reduction in serum total antioxidant capacity (TAC) during HTLV-1 infection and this study was set out to investigate the reasons for TAC reduction.Hypothesis/Gap Statement. Oxidant/antioxidant imbalance during HTLV-1 infection may result from disruptions in oxidant levels or antioxidant defence system.Aim. This study aimed to analyse the key enzymes and oxidant molecules playing important roles in virus-induced oxidative stress.Methodology. We measured serum activities of the major antioxidant enzymes; superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPX) as well as serum concentrations of the main oxidant markers: nitric oxide (NO) and malondialdehyde (MDA). Totally 40 HTLV-1 infected patients and 40 healthy controls were enrolled in this study. The patient group consisted of chronic carriers and patients with HAM-TSP (N=20).Results. The current study found that serum levels of MDA and NO were significantly higher in patient groups particularly in HAM-TSP patients (P<0.05). In addition, a reductive trend was observed in the serum activities of CAT, SOD, and GPX in HTLV-1 infected patients compared with healthy controls (P<0.05).Conclusion. Reduced activities of CAT, SOD, and GPX antioxidant enzymes along with the observed elevated concentrations of oxidant molecules may contribute to oxidative stress and worse outcomes during HTLV-1 infection.

Balance Impairments in Patients with Human T-Cell Lymphotropic Virus Type 1 Infection

The human T-cell lymphotropic virus type 1 (HTLV-1) is a retrovirus from the Retroviridae family that infects cluster of differentiation 4 (CD4) T-lymphocytes and stimulates their proliferation. A severe consequence of this infection can be the HTLV-1 associated myelopathy/tropical spastic paraparesis (HAM/TSP), which is associated with a progressive demyelinating disease of the upper motor neurons. The HAM/TSP conditions frequently present with neurological complaints such as gait impairment, sphincter disturbances, and several sensory losses. We compared findings from the posturographic evaluation from the asymptomatic HTLV-1 infected subjects, HTLV-1 infected subjects having HAM/TSP, and control group database. A force plate was used to record the postural oscillations. Analysis of variance and multivariate linear discriminant analysis were used to compare the data obtained from the three groups of participants. In general, HAM/TSP patients had worse postural balance control than did the HTLV-1 patients and the controls (p < 0.05). We found that in six out of ten parameters of the postural balance control, there was a gradual increase in impairment from control to HTLV-1 to HAM/TSP groups. All parameters had higher values with the subject’s eyes closed. The multivariate linear discriminant analysis showed there was a reasonable difference in results between the control and HAM/TSP groups, and the HTLV-1 group was at the intersecting area between them. We found that HAM/TSP patients had worse balance control than did HTLV-1 infected patients and the control group, but asymptomatic HTLV-1 infected patients represent an intermediate balance control status between controls and HAM/TSP patients. Posturographic parameters can be relied on to identify subtle changes in the balance of HTLV-1 patients and to monitor their functional loss. HTLV-1 is a tropical disease that can be transmitted by sexual intercourse, blood transfusion, and breast-feeding. Some infected subjects develop an HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP), a condition characterized by spasticity, weakness in lower limbs, and difficulty in walking long distances and going up and down the stairs, besides the history of falls. We compared the body oscillations using a force plate to investigate the postural balance control. HTLV-1 infected patients had imbalance that could be identified by posturographic parameters. Patients with HAM/TSP clearly had balance impairments, while HTLV-1 without HAM/TSP had a subtle impairment that was not seen on clinical scales, suggesting that these patients were in the middle between healthy and HAM/TSP patients, and carried a risk of developing severe imbalance postural control. We suggest that more research should be done with the aim to identify the subtle signs in asymptomatic HTLV-1 patients to investigate if this group of patients need attention similar to the HAM/TSP patients.

Protein Profile of Blood Monocytes is Altered in HTLV-1 Infected Patients: Implications for HAM/TSP Disease

Human T-cell lymphotropic virus type-1 (HTLV-1) is the etiological agent of HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). The endothelial breakdown and migration of leukocytes, including monocytes, to the spinal cord are involved in HAM/TSP development. Monocytes from HTLV-1-infected individuals exhibit important functional differences when compared to cells from uninfected donors. Using proteomic shot gun strategy, performed by nanoACQUITY-UPLC system, we analyzed monocytes isolated from peripheral blood of asymptomatic carriers (AC), HAM/TSP and uninfected individuals. 534 proteins were identified among which 376 were quantified by ExpressionE software. Our study revealed a panel of changes in protein expression linked to HTLV-1 infection. Upregulation of heat shock proteins and downregulation of canonical histone expression were observed in monocytes from HTLV-1-infected patients. Moreover, expression of cytoskeleton proteins was increased in monocytes from HTLV-1-infected patients, mainly in those from HAM/TSP, which was confirmed by flow cytometry and fluorescence microscopy. Importantly, functional assays demonstrated that monocytes from HAM/TSP patients present higher ability for adhesion and transmigration thought endothelium than those from AC and uninfected individuals. The major changes on monocyte protein profile were detected in HAM/TSP patients, suggesting that these alterations exert a relevant role in the establishment of HAM/TSP.

HTLV-1 Associated Neurological Disorders.

Human T-cell lymphotropic virus type 1 (HTLV-1) is a retrovirus which is endemic to certain regions of the world and infects around 10-20 million people. HTLV-1 is the etiologic agent of Adult T cell leukemia/lymphoma and HTLV-1 associated neurological disorders including mainly HTLV-1 associated myelopathy/Tropical spastic paraparesis. The involvement of the central nervous diseases occurs among: HTLV-1 infected patients from endemic areas, HIV positive individuals and drug users. The ability of HTLV-1 to cause associated neuropathies starts with the virus crossing the blood brain barrier (BBB), then entering and infecting the cells of the central nervous system. As a consequence, to the viral attack, HTLV-1 infected lymphocytes produce pro-inflammatory cytokines like tumor necrosis factor alpha, Interleukin 1 beta and interleukin 6 which further disrupts the BBB. Different serological tests have been used in the diagnosis of HTLV-1. These include: ELISA, Western Blotting (WB), Immunofluorescence, Particle Agglutination and Polymerase Chain Reaction which is used as a confirmatory test. Danazol, pentoxifylline, azathioprine and vitamin C have been used in the treatment of the HTLV-1 associated neurological disorders. Other antiviral drugs (lamivudine, zidovudine), monoclonal antibodies (Daclizumab) and therapeutic agents (valporic acid, interferons) have also been evaluated. No known drug, so far, has been shown to be efficacious. The aim of this review is to present the complexities of HTLV-1 associated neurological disorders and their current ongoing treatment. In addition to discussing future possible therapeutic strategies, by targeting HTVL-1 viral components and gene/s products, for the treatment of those neurological conditions.

Factors associated with pain in individuals infected by human T-cell lymphotropic virus type 1 (HTLV-1)

IntroductionDespite the high prevalence of chronic pain in individuals infected with HTLV-1, predictive and protective factors for its development are still unclear. ObjectiveTo identify factors associated with chronic pain in individuals with HTLV-1. MethodsThis cross-sectional study was conducted in a reference center for treatment of patients infected with HTLV-1 in Salvador, Bahia, Brazil. The study included individuals infected with HTLV-1, over 18 years, and excluded those with difficulty to respond the pain protocol. Data on sociodemographic, health behavior, and clinical characteristics were collected in a standardized way. The prevalence ratio (PR) of pain is described, as well as the factors independently associated with the presence of pain, which were assessed by multiple logistic regression. ResultsA total of 142 individuals were included in the study, mostly female (62.7%), aged 20–64 years (73.2%), married (61.3%), with less than eight years of education (54.2%), and with a steady income (79.6%). Multivariate analysis showed that being symptomatic for HTLV-1 – sensory manifestations, erectile dysfunction, overactive bladder, and/or HAM/TSP (PR=1.21, 95% CI: 1.05 to 1.38), self-medication (PR=1.29, 95% CI: 1.08–1.53), physiotherapy (PR=1.15, 95% CI: 1.02–1.28), and depression (PR=1.14, 95% CI: 1.01–1.29) were associated with an increased likelihood of presenting pain. On the other hand, physical activity (PR=0.79, 95% CI: 0.67–0.93) and religious practice (PR=0.83, 95% CI: 0.72–0.95) were associated with a decreased likelihood of having pain. ConclusionThe use of self-medication, physiotherapy and the presence of depression are independently associated with neurological symptoms in HTLV-1 infected patients. Religious practice and physical activity are both protective for the development of pain.

Barefoot Plantar Pressure Indicates Progressive Neurological Damage in Patients with Human T-Cell Lymphotropic Virus Type 1 Infection.

BackgroundThe human T-Cell Lymphotropic Virus Type 1 (HTLV-1) is a retrovirus associated with neurological alterations; individuals with HTLV-1 infection may develop HTLV-1 associated myelopathy / tropical spastic paraparesis (HAM/TSP). Frequent neurological complaints include foot numbness and leg weakness. In this study, we compared the distribution of the body weight on different areas of the foot in HTLV-1 patients with HAM/TSP, asymptomatic HTLV-1 patients, and healthy individuals.MethodologyWe studied 36 HTLV-1 infected patients, who were divided in two groups of 18 patients each based on whether or not they had been diagnosed with HAM/TSP, and 17 control subjects. The evaluation included an interview on the patient’s clinical history and examinations of the patient’s reflexes, foot skin tactile sensitivity, and risk of falling. The pressure distribution on different areas of the foot was measured with baropodometry, using a pressure platform, while the patients had their eyes open or closed.Main FindingsThe prevalence of neurological disturbances—altered reflexes and skin tactile sensitivity and increased risk of falling—was higher in HTLV-1 HAM/TSP patients than in HTLV-1 asymptomatic patients. The medium and maximum pressure values were higher in the forefoot than in the midfoot and hindfoot in both HTLV-1 groups. In addition, the pressure on the hindfoot was lower in HAM/TSP patients compared to control subjects.ConclusionsThe neurological disturbances associated with HTLV-1 infection gradually worsened from HTLV-1 asymptomatic patients to HAM/TSP patients. Baropodometry is a valuable tool to establish the extent of neurological damage in patients suffering from HTLV-1 infection.

Molecular characterization of heterogeneity in adult T-cell leukaemia/lymphoma

Adult T cell leukaemia/lymphoma (ATL) is a highly heterogeneous neoplasm caused by human T cell lymphotropic virus type 1 (HTLV-1) infection. Shimoyama et al first proposed a prognostic classification based on clinical features. However subsequent studies have highlighted even greater heterogeneity and progression from indolent to aggressive subtypes. The molecular basis for this heterogeneity and progression remains unknown. Our aims were to identify molecular markers that characterize this heterogeneity and progression. We studied expression of T-cell markers and clonality (Ligation Mediated PCR) on peripheral blood mononuclear cells in samples collected from HTLV-1 infected patients (16 asymptomatic carrier [AC], 18 with HTLV-1-associated myelopathy [HAM], 18 with indolent ATL [five smouldering & 13 chronic] and seven with acute ATL) attending the National Centre for Human Retrovirology, London. 11/18 indolent ATL required no systemic treatment and one progressed to acute ATL. The remainder required systemic therapy and all except one achieved complete remission with zidovudine/interferon. 6/7 with acute ATL had primary refractory disease. Clonality testing showed no dominant clones in the AC, patient with HAM and 6 of the 11 patients with indolent ATL who didn't require systemic therapy. We confirmed CD4+CCR4+ as the main reservoir of HTLV-1 infection. These CD4+CCR4+ T cells had CD7+CD25+CD26+CD127+CCR7-immunophenotype in AC, HAM and indolent ATL with no dominant clones. CD7 down-regulation within CD4+CCR4+ T cells identified ATL patients with dominant clone(s). CD127 down-regulation within CD4+CCR4+ T cells was present in all indolent ATL patients which required systemic therapy. Nine patients with ATL (all acute and two indolent) had CCR7 up- regulation of which all but two had primary refractory disease. Longitudinal follow up in six patients showing changing immunophenotype which correlated with clinical features and prognosis. In conclusion CD7, CD127 and CCR7 expression within CD4+CCR4+ infected cells further characterises the heterogeneity within ATL with therapeutic implications.

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.

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. The incidence of HAM/TSP and new signs and neurologic symptoms were computed in a group of patients enrolled in a cohort study. 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. Development of neurological symptoms or signs occurred in up to 30% of asymptomatic subjects during 8 years of follow-up.

Prevalence and influence of tuberculosis in the neurologic manifestations of the Human T cell lymphotropic virus type 1 (HTLV-1)

HTLV-1 infects mainly T cells, leading to activation and cellular proliferation with exaggerated production of pro-inflammatory cytokines. The majority of HTLV-1 infected patients are considered as HTLV-1 carriers, but 5% will develop HTLV-1 associated myelopathy (HAM) and about 15% overactive bladder, an oligosymptomatic form of HAM. HTLV-1 is associated with increased susceptibility to Mycobacterium tuberculosis infection but up to now it is unknown if HTLV-1 influences the severity of tuberculosis and if tuberculosis may influence the outcome of HTLV-1. The aims of this study were to determine the prevalence and severity of tuberculosis (TB) in HTLV-1 infected patients and analyze whether TB influences the outcome of HTLV-1 infection. This is a cross-sectional study, in which the prevalence of tuberculosis was analyzed in 166 HTLV-1 infected individuals. Cytokine productions were determined by ELISA, the proviral load was evaluated by PCR. Tuberculosis occurred in 33 (22%) of cases and 70 (42%) had a positive tuberculin skin test (TST) (latent tuberculosis). The majority of the cases did not have severe tuberculosis. There was no difference in the proviral load, but there was a higher frequency of HAM/TSP in the group with tuberculosis than in HTLV-1 infected subjects without TB (P<0.05). This study shows that the prevalence of M.tuberculosis infection is 6 fold higher in HTLV-1 infected individuals than that described in the Brazilian population the majority of co-infected had latent tuberculosis and HTLV-1 may influence progression from infection to HAM/TSP.

CD25+CCR4+ cells as a marker of HTLV-1-infected cells in peripheral blood

The diagnosis of Human T cell Lymphotropic Virus type 1 (HTLV-1) infection is based on serology and PCR. The burden of HTLV-1 viral infection is monitored by measuring the proviral load [PVL] in peripheral blood. This assay is not useful for isolation of HTLV-1-infected cells. HTLV-1 Tax upregulates CD25 expression on infected CD4+ T cells. However, CD4+CD25+ is also the phenotype of activated T cells. CCR4 is a chemokine receptor expressed on subsets of activated T cells. HTLV-1-infected cells secrete the CCR4 ligand CCL22, and preferentially infect CCR4+ Cells. We studied the expression of CD25 and CCR4 in lymphocytes and its relation to PVL. We performed 11-colour immunophenotyping and HTLV-1 PVL quantification on 53 samples obtained from 36 HTLV-1 infected patients, [10 asymptomatic carriers (AC); 11 patients with HTLV-1-associated myelopathy (HAM); 4 co-infected with HIV; 11 with chronic/smouldering adult T-cell leukaemia/lymphoma (ATL)] and 3 uninfected individuals. Increased frequency of CD25+CCR4+ T cells [median: 14.7%, range: 1.95-91.3%] was observed in all HTLV-1 infected patients; the frequency correlated with PVL [Spearman r=0.89, P <0.001, Linear R2 = 0.61]. CD4+ and CD8+ cells from 12 patients [6ACs and 6 HAMs] were separated for PVL estimation. CD25+ CCR4+ cell counts correlated closely with PVL in CD4+ cells [Spearman r=0.816, P <0.001, linear R2=0.886] but not in CD8+ cells. Frequency of CD25+CCR4+ T cells correlated with PVL change in treated ATL patients. We conclude that CD25+CCR4+ cells can be used as a specific marker for monitoring of HTLV-1 infection and isolation of HTLV-1 infected cells.

Epitopes recognised by neutralising and non-neutralising anti-envelope antibodies define surface exposed regions of HTLV-1 envelope

Infection of human cells by human T cell lymphotropic virus type 1 (HTLV-1) is mediated by the viral envelope glycoproteins. The gp46 surface glycoprotein binds to cell surface receptors, including heparan sulfate proteoglycans, neuropilin 1, and glucose transporter 1, allowing the transmembrane glycoprotein (TM, gp21) to initiate fusion of the viral and cellular membranes. The envelope glycoproteins are recognized by neutralizing Abs and CTL following a protective immune response and, therefore, represent attractive components for a HTLV-1 vaccine. Recently, we demonstrated that recombinant forms of surface glycoprotein (sRgp46) or TM are capable of eliciting polyclonal antibody responses following vaccination in a murine model. Analysis of monoclonal antibodies derived from these animals indicates that they exhibit properties that are typical of those observed in natural human infections. We now demonstrate that neutralizing antibodies appear to recognize a limited set of surface accessible neutralising epitopes. We have mapped some of these epitopes at amino acid resolution and demonstrate that several overlapping epitopes within the receptor-binding domain of SU define a hotspot for recognition by neutralising antibodies. Surprisingly, some non-neutralising monoclonal antibodies also appear to recognise surface exposed epitopes of SU; models for sensitivity to neutralisation will be discussed. Finally, we demonstrate that many HTLV-1 infected patients direct antibodies to gp21 TM, but this activity is largely unable to block viral infectivity. The implications of our findings for HTLV-1 pathogenesis and vaccine development will be discussed.

Modulation of glutathione intracellular levels alters the spontaneous proliferation of lymphocyte from HTLV-1 infected patients

The human T-cell lymphotropic virus type 1 (HTLV-1) is a retrovirus associated with neoplasias and inflammatory diseases, such as adult T-cell leukemia/lymphoma and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). HTLV-1-infected individuals present a spontaneous T lymphocyte proliferation. This phenomenon is related to the HTLV-1-proviral load and the persistence of the infection. Viral proteins induce many cellular mediators, which can be associated with the abnormal cellular proliferation. The intracellular levels of glutathione (GSH) are important to modulate the cellular proliferation. The aim of this study was to investigate the correlation between the modulation of intracellular GSH levels and the spontaneous lymphocyte proliferation during the HTLV-1 infection. Intracellular GSH level can be modulated by using dl-buthionine-[S,R]-sulfoximine (BSO, GSH synthesis inhibitor) and N-acetylcysteine (NAC, peptide precursor). Our results demonstrated that BSO was capable of inducing a decrease in the spontaneous proliferation of PBMC derived from HTLV-1 carriers. On the other hand, the GSH precursor induces an increase in mitogen-stimulated cellular proliferation in infected and uninfected individuals. Similar results were observed by the inhibition of ABCC1/MRP1 protein, augmenting the mitogen-induced proliferation. This effect can be related with an increase in the GSH levels since ABCC1/MRP1 transports GSH to the extracellular medium. There was a significant difference on the expression of CD69 and CD25 molecules during the lymphocyte activation. We did not observe any alterations on CD25 expression induced by BSO or NAC. However, our results demonstrated that NAC treatment induced an increase in CD69 expression on unstimulated CD8+ T lymphocytes obtained from HTLV-1 infected individuals, healthy donors and HTLV carriers. Therefore, our results suggest that the cellular proliferation promoted by the infection with HTLV-1 and the activation phenotype of CD8+ T lymphocytes can be regulated by changing the intracellular GSH levels; suggesting the modulation of these intracellular levels as a new approach for the treatment of pathologies associated with the HTLV-1 infection.

Evolution of HTLV-1 proviral load in patients from Salvador, Brazil

IntroductionVariations in human T cell lymphotropic virus type 1 (HTLV-1) proviral load (PVL) in infected individuals over time are not well understood. ObjectiveTo evaluate the evolution of proviral load in asymptomatic individuals and HAM/TSP patients in order to help determine periodicity for measuring proviral load. MethodsA group of 104 HTLV-1 infected patients, followed at the HTLV reference center in Salvador, Brazil, were included in the study (70 asymptomatic and 34 HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) patients). HTLV-1 PVL was measured using real-time polymerase chain reaction (PCR) at baseline and again at another point, either ≤ 12 months, between 12-24 months, or ≥ 24 months. ResultsHAM/TSP patients had higher PVL (ranging from 11,041 to 317,009 copies/106 PBMC) when compared to asymptomatic individuals (ranging from 0 to 68,228 copies/106 PBMC). No statistically significant differences were observed in the medians of PVL in HAM/TSP patients or asymptomatic individuals over time. However, in asymptomatic individuals with a PVL below 50,000 copies/106 PBMC, a statistically significant two-fold increase was observed over time. ConclusionHTLV-1-PVL remained stable in both asymptomatic individuals and HAM/TSP patients over time. Frequent monitoring of asymptomatic individuals with low PVLs is recommended and further studies should be conducted to assess the course of PVL in these patients over extended periods of time.

Keratoconjunctivitis sicca of human T cell lymphotropic virus type 1 (HTLV-1) infected individuals is associated with high levels of HTLV-1 proviral load

Background A high HTLV-1 proviral load is found in HTLV-1-associated diseases, mainly HAM/TSP. However, the association between proviral load and keratoconjunctivitis sicca (KCS) has not been well established. Aim To verify the association between KCS and HTLV-1 proviral load. Study design 104 HTLV-1 infected patients (51 asymptomatic and 52 with HAM/TSP) from the HTLV reference center in Salvador, Brazil were followed from June 2008 to May 2010. Evaluation of tear secretion was performed by BUT (break-up time), Rose Bengal and Schirmer I tests. The diagnosis of KCS was based upon the presence of symptoms and when at least two of three tests were positive. HTLV-1 proviral load was determined using real-time PCR. Results The prevalence of KCS was 44.2%. KCS was more frequent among HAM/TSP patients ( p = 0.022). Patients with KCS had higher proviral load (mean 134,672 ± 150,393 copies/10 6 PBMC) than patients without the disease (mean 66,880 ± 109,525 copies/10 6 PBMC) ( p = 0.001). HTLV-1 proviral load > 100,000 copies/10 6 PBMC increased significantly the risk of developing KCS (OR = 4.05 and 95% CI = 1.40–11.76). After age > 45 years and HAM/TSP status were excluded in stepway reward analysis, the variables PVL > 100,000 (OR = 4.77 and 95% CI = 1.83–12.44) still remained statistically significant. Conclusion HTLV-1 proviral loads are higher in patients with KCS and may represent a relevant biological marker of disease.

Spontaneous neutrophil activation in HTLV-1 infected patients

Human T cell lymphotropic Virus type-1 (HTLV-1) induces lymphocyte activation and proliferation, but little is known about the innate immune response due to HTLV-1 infection. We evaluated the percentage of neutrophils that metabolize Nitroblue tetrazolium (NBT) to formazan in HTLV-1 infected subjects and the association between neutrophil activation and IFN-gamma and TNF-alpha levels. Blood was collected from 35 HTLV-1 carriers, from 8 patients with HAM/TSP (HTLV-1- associated myelopathy); 22 healthy individuals were evaluated for spontaneous and lipopolysaccharide (LPS)-stimulated neutrophil activity (reduction of NBT to formazan). The production of IFN-gamma and TNF-alpha by unstimulated mononuclear cells was determined by ELISA. Spontaneous NBT levels, as well as spontaneous IFN-gamma and TNF-alpha production, were significantly higher (p<0.001) in HTLV-1 infected subjects than in healthy individuals. A trend towards a positive correlation was noted, with increasing percentage of NBT positive neutrophils and levels of IFN-gamma. The high IFN-gamma producing HTLV-1 patient group had significantly greater NBT than healthy controls, 43+/-24% and 17+/-4.8% respectively (p< 0.001), while no significant difference was observed between healthy controls and the low IFN-gamma-producing HTLV-1 patient group (30+/-20%). Spontaneous neutrophil activation is another marker of immune perturbation resulting from HTLV-1 infection. In vivo activation of neutrophils observed in HTLV-1 infected subjects is likely to be the same process that causes spontaneous IFN-gamma production, or it may partially result from direct IFN-gamma stimulation.