Human T-lymphotropic Virus 1 Carriers Research Articles

Period prevalence of uveitis in human T-lymphotropic virus 1carriers versus noncarriers in a highly endemic area: The Nagasaki Islands Study.

The magnitude of the effect of human T-lymphotropic virus 1 (HTLV-1) infection on uveitis remains unclear. We conducted a cross-sectional study in a highly endemic area of HTLV-1 in Japan. The study included 4265 residents (men, 39.2%), mostly middle-aged and older individuals with a mean age of 69.9 years, who participated in our surveys between April 2016 and September 2022. We identified HTLV-1 carriers by screening using chemiluminescent enzyme immunoassays and confirmatory tests, and the proportion of carriers was 16.1%. Participants with uveitis were determined from the medical records of all hospitals and clinics where certified ophthalmologists practiced. We conducted logistic regression analyses in an age- and sex-adjusted model to compute the odds ratio (OR) and 95% confidence interval (CI) of uveitis according to HTLV-1 infection status. Thirty-two (0.8%) participants had uveitis. For HTLV-1 carriers, the age- and sex-adjusted OR (95% CI) of uveitis was 3.27 (1.57-6.72) compared with noncarriers. In conclusion, HTLV-1 infection was associated with a higher risk of uveitis among mostly middle-aged and older Japanese residents in a highly endemic HTLV-1 area. Our findings suggest that physicians who treat HTLV-1 carriers should assess ocular symptoms, and those who diagnose patients with uveitis should consider HTLV-1 infection.

Lower prevalence of anti-HTLV-1 as expected by previous models among first-time blood donors in Japan.

An estimated 1.08 million carriers of human T-lymphotropic virus 1 (HTLV-1) were living in Japan in 2006-2007. Since that study, new data on horizontal infection, nationwide antenatal screening for anti-HTLV-1 in pregnant women, and social educational campaigns on HTLV-1 infection have emerged in Japan. To estimate the current number of HTLV-1 carriers in Japan, confirmed HTLV-1 infections among first-time blood donors in 2020-2021 from across Japan were investigated. Age-, sex- and geographic area-specific information associated with HTLV-1 antibody detection was evaluated. Data obtained were compared with predictions based on 2006-2007 data, considering a birth cohort effect that assumed lifelong maintenance of seropositivity.HTLV-1 seroprevalence in women was almost equivalent to that in men. The prevalence in men was similar to that predicted from 2006 to 2007 data. In contrast, the prevalence in women was lower in all age strata than that predicted by each birth cohort. The estimate for the entirety of Japan was 534 000 carriers from measured prevalence, whereas that from the birth cohort effect-adjusted prevalence was 658 000. The number of HTLV-1 carriers in Japan was estimated to have decreased by approximately 40% during the past 14 years.

Evolution of erectile dysfunction in individuals infected with human T-lymphotropic virus 1: a prospective cohort study.

Virtually all patients with human T-lymphotropic virus 1 (HTLV-1)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) have some degree of erectile dysfunction (ED), but ED is also found in a large percentage of HTLV-1 carriers. To evaluate the evolution of ED in individuals infected with HTLV-1 who were followed for up to 15years. This prospective cohort study included men infected with HTLV-1 who had ED, were aged 18 to 70years, and were followed from January 2004 to December 2019. We used the International Index of Erectile Function-5 (IIEF-5), the Expanded Disability Status Scale and Osame Motor Disability Scale, and the Overactive Bladder Symptom Score (OABSS) to define and stratify ED, neurologic disability, and bladder dysfunction, respectively. Time to development of severe ED was the main outcome. We studied 90 men with ED (mean ± SD age, 52.8 ± 9.78years). At baseline, 42 were carriers, 16 had probable HAM/TSP, and 32 had definite HAM/TSP. IIEF-5 was highest among carriers and lowest in patients with definite HAM/TSP, whereas OABSS was lowest in carriers and highest in patients with definite HAM/TSP. Median (IQR) follow-up was 8.50 years (3.00-12.00). IIEF-5 fell significantly from baseline to last follow-up among carriers and patients with probable and definite HAM/TSP. There was an inverse correlation between the IIEF-5 and the OABSS at last follow-up (r = -0.62, P < .001). In survival analysis, the time to development of severe ED was significantly shorter in patients with definite HAM/TSP when compared with carriers (P = .001) and those with probable HAM/TSP (P = .014). The presence of definite HAM/TSP at baseline was independently associated with the development of severe ED, after adjustment for baseline age and proviral load (hazard ratio, 6.74; P = .008). Formal assessment of erectile function should be part of the routine clinical assessment of individuals infected with HTLV-1; worsening erectile function should alert clinicians to the possibility of neurologic deterioration. This is the first prospective cohort study to describe the course of ED in men infected with HTLV-1. The small sample size and absence of seronegative controls are limitations. ED is a slowly progressive clinical manifestation of HTLV-1 infection, and the degree of neurologic compromise at baseline is the main predictor of time to progression to severe ED.

The Expression of Tax and HBZ Genes in Serum-Derived Extracellular Vesicles From HTLV-1 Carriers Correlates to Proviral Load and Inflammatory Markers.

Human T-lymphotropic virus 1 (HTLV-1) is the etiologic agent of adult cell leukemia/lymphoma (ATL) and HTLV-1 associated myelopathy/tropical spastic paraparesis (HAM/TSP). One of the major questions in HTLV-1 studies is related to the understanding of causes that lead to different clinical manifestations. However, it is well known that the viral genes tax and HTLV-1 basic leucine zipper factor (HBZ) are related to viral infectivity and the development of neurological and hematological diseases. Currently, there is evidence that HTLV-1 infected cells can release small extracellular vesicles (sEVs) involved in the mechanisms of viral particles spreading. Therefore, we evaluated the expression levels of tax and HBZ viral transcripts in serum-derived sEVs from HTLV-1 carriers, as well as the role of these vesicles in the modulation of the immune response. Three HAM/TSP carriers presented detectable levels of tax and HBZ transcripts in sEVs and were positively correlated to the proviral load (PVL) in peripheral blood mononuclear cells (PBMCs). The viral transcripts were only detectable in individuals with a PVL higher than 6,000/105 PBMCs. Additionally, it was observed that HBZ presented a 2–12-folds increase over tax expression units. Gene expression and secretory protein analysis indicated that PBMCs from blood donors and HTLV-1 carriers exposed to increasing doses of tax+ HBZ+ sEVs showed a dose-dependent increase in interferon (IFN)-γ and interleukin (IL)-8 transcripts and proteins. Interestingly, the increase in IL-8 levels was close to those seen in HTLV-1-infected PBMCs with high PVL. Taken together, these findings indicate that the expression of viral transcripts in serum-derived sEVs of HTLV-1 carriers is related to the PVL presented by the infected individual. Additionally, tax+ HBZ+ sEVs can induce the production of inflammatory cytokines in patients with low PVL, which may be related to the development of symptoms in HTLV-1 infection.

Low prevalence of human pegivirus 1 (HPgV-1) in HTLV-1 carriers from Belém, Pará, North Region of Brazil.

Human pegivirus 1 (HPgV-1) is a single-stranded, positive-sense RNA virus belonging to the Flaviviridae family with limited cause-effect evidence of the causation of human diseases. However, studies have shown a potential beneficial impact of HPgV-1 coinfection in HIV disease progression. Human T lymphotropic virus-1 (HTLV-1) is a retrovirus known for causing diseases, especially in muscle and white blood cells, in approximately 5% of patients. Thus, this study aimed to investigate the potential effects of an HPgV-1 infection in patients carrying HTLV-1 in the state of Pará in the North Region of Brazil. A group of HTLV-1 carriers was compared to healthy controls. Blood samples were collected, data from medical regards were collected, and a questionnaire was administered. HPgV-1 and HTLV-1 positivity was determined by quantitative polymerase chain reaction (qRT-PCR). The data were analyzed to correlate the effects of HPgV-1 coinfection in HTLV-1 carriers. A total of 158 samples were included in the study: 74 HTLV-1-positive patients (46,8%) and 84 healthy controls (53,2%). The overall HPgV-1 positivity rate was 7.6% (12/158), resulting in a prevalence of 5.4% (4/74) and 9.5% (8/84) in HTLV-1 carriers and healthy controls, respectively. No significant differences were found when comparing any clinical or demographic data between groups. This study indicated that the prevalence of HPgV-1 infection is low in HTLV-1 carriers in Belém, Pará, and probably does not alter the clinical course of HTLV-1 infection, however, further studies are still needed.

CD4+ Lymphocytes in Asymptomatic HTLV-1 Carriers Present Cell Cycle Arrest in G0/G1-Phase

Introduction: Adult T-cell leukemia/lymphoma (ATLL) is an aggressive and incurable disease caused by human T-lymphotropic virus 1 (HTLV-1) that infects CD4+ and CD8+ lymphocytes, but most commonly the malignant cell present a CD4+ phenotype. However, clonal expansion and cell cycle abnormalities have been demonstrated in CD4+ and in CD8+ lymphocytes of HTLV-1 carriers.Objectives: This study compared DNA content and G0/G1, G2/M and “S”-phases of CD4+ and CD8+ lymphocytes among asymptomatic HTLV-1 carriers, ATLL and health subjects.Methods: Werestudied 38 HTLV-1 carriers, 20 ATLL and 35 health subjects pared by sex and age at the Hematology Department of the Faculty of Medicine, University of São Paulo. Peripheral blood mononuclear cells (PBMCs) were isolated on Ficoll-Paque® and lymphocytes subtypes were obtained by positive selection in a magnetic column. Cell-cycle distribution and DNA index (DI) was assessed by flow cytometry after propidium iodide staining.Results: In ATLL, themedian age was 53.5 years (24 to 72) and 50% were female, in HTLV-1 carriers was 55.5 years (33 to 80) with 63.2% of female and in control group was 50 years (24 to 80) with 54.3% of female. In the CD4+ lymphocyte a % of cells in G0/G1 (98.32%) in HTLV-1 carriers was higher than in control group (97.14%) (p=0.041) and in ATLL (97.25%) (p=0.023). S-phase was not statistically different in asymptomatic carriers (0.34%) and control group (0.63%) (p=0.073), but was higher in ATLL (1.80%) than in asymptomatic carriers (0.34%) (p<0.001) and in control group (0.63%) (p=0.02). G2/M-phase was not significantly different among all groups (p=0.960) (Table 1). The CD4+ lymphocytes were aneuploidy in 39.5% (18.4% DI > 1.05 and 21.5% < 0.95) of asymptomatic carriers and in 26.7% (20% > 1.05 and 6.7% < 0.95) of ATLL patients (p=0.557). All control groups were diploid. Table 1Comparison of the cell cycle by flow cytometry of T lymphocytes CD4+CD4+ cellsAsymptomatic carriersATLLControl groupp-ValueG0/G1mean(dp)97.78 (2.182)95.69 (3.557)96.55 (2.964)0.0351º; median;3ºq97.03;98.32;99.6491.40;97.25;98.3295.01;97.14;98.64G2/Mmean(dp)1.55(1.848)1.91(2.798)2.03(2.902)0.961º; median;3ºq0.00;0.88;2.670.12;0.99;1.990.00;0.56;2.97S-phasemean(dp)0.68(1.207)2.80(3.372)1.43(1.780)0.0031º; median;3ºq0.00;0.34;0.650.65;1.80;3.510.04;0.63;2.55In CD8+ there was no found significantly difference in whole groups for G0/G1-phase (p=0.138) and G2/M-phase (p=0.374). ATLL presented higher S-phase (median 1.54%) than asymptomatic carriers (median 0.45%) (p=0.003) and control group. S-phase in asymptomatic carriers was not significantly different in comparison to control group (p=0.712). CD8+ were aneuploidy in 23.7% (5.3% DI > 1.05 and 18.4% < 0.95) of asymptomatic carriers and in 21% (10.5% > 1.05 and 10.5% < 0.95) of ATLL (p=0.603). In ATLL the median of DI was 1.01 (1.0; 1.05) in CD4+ and higher than in CD8+ median 0.99 (0.98; 1.0) (p=0.007). Aneuploidia was seen in 47.7% of ATLL, 26,7% (20% DI > 1.05 and 6,7% < 0.95) in CD4+ and 21,0% in CD8+ (10,5% > 1.05 and10,5% < 0.95) (p=0.625). [Display omitted] [Display omitted] [Display omitted] Conclusion:We demonstrated for the first time “in vivo” that asymptomatic HTLV-1 carriers display cell cycle arrest in G0/G1-phase in CD4+ lymphocytes and high rate of aneuploidia in both CD4+ and CD8+. ATLL showed high rate of hiperdiploidia in CD4+ and hipodiploidia in CD8+ and high rate of S-phase in CD4+. Genetic instability and proliferative disturbs are a hallmark not only in ATLL but also in HTLV-1 carriers and in both CD4+ and CD8+ lymphocytes. DisclosuresNo relevant conflicts of interest to declare.

NLRP3 polymorphism is associated with protection against human T-lymphotropic virus 1 infection

Inter-individual heterogeneity in the response to human T-lymphotropic virus 1 (HTLV-1) infection has been partially attributed to host genetic background. The antiviral activity of the inflammasome cytoplasmic complex recognises viral molecular patterns and regulates immune responses via the activation of interleukin (IL)-1 family (IL-1, IL-18 and IL-33) members. The association between polymorphisms in the inflammasome receptors NLRP1 and NLRP3 and HTLV-1 infection was evaluated in a northeastern Brazilian population (84 HTLV-1 carriers and 155 healthy controls). NLRP3 rs10754558 G/G was associated with protection against HTLV-1 infection (p = 0.012; odds ratio = 0.37). rs10754558 affects NLRP3 mRNA stability; therefore, our results suggest that higher NLRP3 expression may augment first-line defences, leading to the effective protection against HTLV-1 infection.

IFN‐γ production in response to Tax 161–233, and frequency of CD4+ Foxp3+ and Lin− HLA‐DRhigh CD123+ cells, discriminate HAM/TSP patients from asymptomatic HTLV‐1‐carriers in a Peruvian population

Human T-lymphotropic virus 1 (HTLV-1) can cause HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). The objective of this study was to gain insight into the pathogenesis of HAM/TSP by focusing on the CD8(+) T-cell response. Twenty-three HTLV-1-seronegative controls (SC), 29 asymptomatic HTLV-1 carriers (AC) and 48 patients with HAM/TSP were enrolled in the study. We evaluated the production of interferon-gamma (IFN-gamma) in peripheral blood mononuclear cells stimulated with Tax overlapping peptides, the expression of genes related to the CD8(+) cytotoxic T-cell response, the frequency of CD4(+) Foxp3(+) cells and of dendritic cells, and the HTLV-1 provirus load (PVL). The frequency of cells producing IFN-gamma in response to Tax 161-233, but not to Tax 11-19, discriminated patients with HAM/TSP from AC. The increased pro-inflammatory response observed in patients with HAM/TSP was shared by AC with a high PVL, who also exhibited lower levels of granzyme H mRNA in unstimulated CD8(+) T cells than AC with a low PVL. Patients with HAM/TSP showed higher frequencies of CD4(+) Foxp3(+) cells and lower frequencies of plasmacytoid dendritic cells (pDC) than AC. Our findings are consistent with a model in which HTLV-1, along with the host genetic background, drives quantitative and qualitative changes in pDC and CD4(+) Foxp3(+) cells that lead to a predominance of inflammatory responses over lytic responses in the CD8(+) T-cell response of individuals predisposed to develop HAM/TSP.

Association between ABO and Rhesus Blood Group Systems among Confirmed Human T Lymphotropic Virus Type 1-Infected Patients in Northeast Iran

The distribution of ABO and Rhesus blood group types was investigated in 984 randomly selected human T lymphotropic virus-1(HTLV-1)-infected blood donors from April 2004 to March 2007. A total of 1081 healthy controls admitted for blood donation in this period were enrolled in this study. Infected and control individuals were from the same region and their ABO/Rhesus blood group types were determined by the standard tube test technique. All blood samples were screened for HTLV-1 using an enzyme-linked immunosorbent assay (ELISA) and positive samples were confirmed by Western blot (WB). The unmatched analyses showed significant differences in frequency of the A+ blood group between healthy controls and HTLV-1-infected individuals (OR = 0.8, 95% CI = 0.66-0.97) and also a significant association was observed between these two groups(OR = 1.42, 95% CI = 1.1-1.99, p = 0.021). No significant difference in blood group (A-, B+, B-, O+, O-, and AB-) was observed between cases and controls. It is the first report of an association between HTLV-1-infected patients and ABO/Rh blood groups in our literature review. Our results might suggest that the A+ blood group decrease the risk of HTLV-1 infection in healthy controls, while the AB+ blood group is more frequent in HTLV-1 carriers and increases the risk of HTLV-1 infection.

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

AbstractCD4+ 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.