Evaluation of T Regulatory Lymphocytes Transcription Factors in HTLV-1-Associated Myelopathy/Tropical Spastic Paraparesis (HAM/TSP) Patients

The FOXP3-924 A/G Single Nucleotide Polymorphism May Be Associated with Predictive Factors for Human T Lymphotropic Virus 1 Associated Myelopathy

Human T lymphotropic virus 1 (HTLV-1) is a retrovirus associated with inflammatory diseases, including HTLV-1-associated myelopathy (HAM), and host genetic factors may be involved in disease evolution. The forkhead Box P3 (FOXP3) transcription factor is linked to homeostasis of the immune system, and the presence of polymorphisms in the promoter region of the FOXP3 gene should reflect its expression levels and consequent activation of regulatory T cells, which may contribute to severe inflammatory disorders, such as HAM. This study evaluated the rs2232365 polymorphism (-924 A/G) located in the promoter region of the FOXP3 gene and its association with HAM. Forty DNA samples from asymptomatic carriers and 25 samples from HAM patients were used, in addition to 130 control samples. The polymorphism was genotyped by conducting real-time polymerase chain reaction (PCR) (quantitative PCR [qPCR]) on extracted DNA. The proviral loads (PVLs) and CD4⁺ and CD8⁺ T lymphocyte counts were determined by qPCR and FACSCalibur flow cytometry, respectively. The PVLs, CD4⁺ T lymphocyte concentrations, and tumor necrosis factor-α dosages were considered predictive factors of the clinical profiles of HTLV-1 infection, all of which had higher levels in the HAM group. Carriers of the GG genotype for the polymorphism rs2232365 had high PVLs and CD4⁺ T lymphocyte concentrations.

Evaluation of iron, ferritin, copper, and ceruloplasmin along with proviral load in human T lymphotropic virus type 1-associated myelopathy

Human T-cell lymphotropic virus type 1 (HTLV-1) infection can cause HTLV-I-associated myelopathy (HAM). In this study, we evaluated the levels of serum iron, ferritin, copper, and ceruloplasmin, and their correlations with HTLV-1 proviral load (PVL) and standard indices of HAM severity. In total, 114 subjects were recruited in this cross sectional study in Qaem Hospital, Mashhad, Iran between 2017 and 2018, including 36 HAM and 32 asymptomatic cases (ACs) and 46 healthy people (HSs). The clinical examination and evaluation of serum levels of biochemical factors and proviral load were performed. The PVL in HAM and ACs were 1835.49 ± 382.81 and 280.97 ± 67.41 copies/104 PBMCs, which statistically differed. Significant differences were also observed in plasma levels of iron, copper, and ceruloplasmin, among the three groups, while ferritin level was not considerably different. For HAM severity, the mean Osame motor disability scale (OMDS) and overactive bladder-validated-8-questionnaire (OABV-8) scores were 4.97 ± 0.38 and 15.75 ± 0.83, respectively, that had no significant correlations with the biochemical variables. Even though the studied elements in HAM group did not affect the severity of the disease, the levels of copper and ceruloplasmin might be determinants of the development and progression of HAM, as they are shown to play role in progression of other neurological diseases.

HTLV-1 oncovirus-host interactions: From entry to the manifestation of associated diseases

Human T lymphotropic virus type-1 (HTLV-1) is a well-known human oncovirus, associated with two life-threatening diseases, adult T cell leukaemia/lymphoma (ATL) and HTLV-1 associated myelopathy/tropical spastic paraparesis (HAM/TSP). The study of this oncogenic virus is significant from two different aspects. First, HTLV-1 can be considered as a neglected public health problem, which may spread slowly worldwide. Second, the incidence of HTLV-1 associated diseases due to oncogenic effects and deterioration of the immune system towards autoimmune diseases are not fully understood. Furthermore, knowledge about viral routes of transmission is important for considering potential interventions, treatments or vaccines in endemic regions. In this review, novel characteristics of HTLV-1, such as the unusual infectivity of virions through the virological synapse, are discussed in the context of the HTLV-1 associated diseases (ATL and HAM/TSP).

Low Annexin A1 level in HTLV-1 infected patients is a potential biomarker for the clinical progression and diagnosis of HAM/TSP

BACKGROUND

Human T-lymphotropic virus 1 (HTLV-1) is etiologically associated with the chronic inflammatory neurodegenerative disease HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) Annexin A1 (AnxA1) is an anti-inflammatory protein with proposed neuroprotective and anti-neuroinflammatory functions. We hypothesized that ANXA1 gene expression may be dysregulated in HTLV-1-infected HAM/TSP patients.

METHODS

This study involved 37 individuals infected with HTLV-1, including 21 asymptomatic (AS) carriers and 16 with HAM/TSP, and a control group of 30 individuals negative for HTLV-1 and HTLV-2. For AS HTLV-1-positive and HAM/TSP patients, ANXA1 and formyl peptide receptor (FPR1, FPR2 and FPR3) expression and HTLV-1 proviral load (PVL) in peripheral blood cells were evaluated by real-time quantitative PCR (qPCR), and plasma AnxA1 levels were determined by enzyme-linked immunosorbent assay (ELISA).

RESULTS

ANXA1 gene expression was increased in the AS group compared with the HAM/TSP and control groups, but the differences were not statistically significant. FPR1 gene expression was higher in patients with HTLV-1 than in controls (AS, p = 0.0032; HAM/TSP, p < 0.0001). Plasma AnxA1 levels were higher in the AS group than in the HAM/TSP group (p = 0.0045), and PVL was higher in patients with HAM/TSP than in AS individuals (p = 0.0162). The use of a combined ROC curve using Annexin 1 levels and proviral load significantly increased the sensitivity and specificity to predict progression to HAM/TSP (AUC = 0.851 and AUC = 0.937, respectively, to AUC = 1000).

CONCLUSIONS

Our results suggest that AnxA1 may be dysregulated in HAM/TSP patients. Serological detection of AnxA1 in association with proviral load may provide a prognostic biomarker for HTLV-1-associated neurodegenerative disease.

Ectonucleotidase CD39 is highly expressed on ATLL cells and is responsible for their immunosuppressive function

Adult T-cell leukemia/lymphoma (ATLL) patients have an extremely poor prognosis, partly due to their immunosuppressive state. The majority of ATLL patients have leukemic cells with phenotype similar to Tregs, prompting suggestions that ATLL cells themselves have immunosuppressive functions. In this study, we detected CD39 expression on ATLL cells, particularly frequent on aggressive subtypes. CD39 and CD73 convert extracellular adenosine triphosphate (ATP) into adenosine, a key player in Tregs’ immunosuppression. In vitro culture, both CD39⁺ ATLL cells and normal Tregs converted rapidly extracellular ATP to AMP, which was disturbed by CD39 inhibitors, and was negated in the CD39 knockout MJ cell line. The proliferation of cocultured CD4⁺/CD8⁺ normal T cells was suppressed by CD39⁺ MJ cells, but not by CD39 knockout MJ cells. Supplemented ATP was exhausted by an EG7-OVA T-cell line with stable CD39 induction, but not by mock. When these cell lines were subcutaneously transplanted into murine flanks, Poly(I:C) peritoneal administration reduced tumor size to 1/3 in mock-transplanted tumors, but not in CD39 induced tumors. Overall, we found that ATLL cells express CD39 at a high rate, and our results suggest that this helps ATLL cells escape antitumor immunity through the extracellular ATPDase-Adenosine cascade. These findings will guide future clinical strategies for ATLL treatment.