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Adult T cell leukemia/lymphoma is a malignancy with a poor prognosis caused by human T lymphocyte virus type 1 (HTLV-1) infection. Tax and HBZ are two major viral proteins that may be involved in oncogenesis by disrupting apoptosis. Because Bcl-xL plays an integral role in the anti-apoptotic pathway, this study examines the interaction between host apoptosis and oncoproteins. We investigated 37 HTLV-1-infected individuals, including 18 asymptomatic and 19 adult T cell leukemia/lymphoma (ATLL) subjects. mRNA was extracted and converted to cDNA from peripheral blood mononuclear cells, and then gene expression was determined using TaqMan q-PCR. Moreover, the HTLV-1 proviral load (PVL) was also measured using a commercial absolute quantification kit (Novin Gene, Iran). Data analysis revealed that the mean of TAX, HBZ, and PVL was significantly higher among the study groups (ATLL and carrier groups p = .003, p = .000, and p = .002 respectively). There was no statistical difference in Bcl-xL gene expression between the study groups (p = .323). It is proposed that this anti-apoptotic pathway may not be directly involved in the development of ATLL lymphoma. Bcl-xL, TAX, HBZ gene expression, and PVL can be utilized as prognostic markers.
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Infecções por HIV , Vírus Linfotrópico T Tipo 1 Humano , Leucemia-Linfoma de Células T do Adulto , Linfoma , Adulto , Humanos , Leucemia-Linfoma de Células T do Adulto/genética , Vírus Linfotrópico T Tipo 1 Humano/genética , Leucócitos Mononucleares , Fatores de Transcrição de Zíper de Leucina Básica/genética , Fatores de Transcrição de Zíper de Leucina Básica/metabolismo , Proteínas dos Retroviridae/genética , Proteínas dos Retroviridae/metabolismo , Infecções por HIV/patologia , Linfoma/patologia , Expressão Gênica , Produtos do Gene tax/genética , Produtos do Gene tax/metabolismoRESUMO
Human T-lymphotropic virus type 1 (HTLV-1) is a retrovirus associated with two life-threatening diseases; HAM/TSP and ATLL. Due to the slow-growing HTLV-1 infection worldwide, WHO urged for elimination. A large border with Afghanistan, northeast Iran is an endemic region for HTLV-1 infection. Historically, Afghanistan has common sociocultural similarities to Persian peoples. This study was conducted to evaluate HTLV-1 prevalence in Afghan refugees. Also, the HTLV-1 transmission rate and understanding of whether or not the Silk Road has been the route of HTLV-1 infection to Iran were investigated. This case-control study was conducted in a rural area of Fariman city, with Afghan residents who migrated around 165 years ago, from 1857, the Treaty of Paris at the end of the Anglo-Persian war, and a refugee camp in Torbat-e-Jam city. These populations in HTLV-1 endemic area were compared to a segregated population of Afghan refugees in Semnan, the centre of Iran. Blood samples of 983 volunteers were assessed with the ELISA method for the presence of HTLV-1 antibodies and then confirmed by PCR technique. All samples from Afghan refugee camps, Semnan and Torbat-e-Jam, were negative for HTLV-1 infection. However, the prevalence of HTLV-1 infection in Fariman, a rural population of Afghan origin, was approximately 2.73%. The results showed that HTLV-1 is not endemic in Afghanistan, a war-stricken region with refugees distributed worldwide. The land Silk Road has not been the route of HTLV-1 transmission to Northeastern Iran. Importantly, HTLV-1 endemicity might occur during a long time of living in an endemic area.
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Objectives: Human T leukemia virus type one (HTLV-1) causes two life-threatening diseases in around five percent of infected subjects, a T cell malignancy and a neurodegenerative disease. TAX and HBZ are the main virulence agents implicated in the manifestation of HTLV-1-associated diseases. Therefore, this study aims to produce these HTLV-1 factors as recombinant Fc fusion proteins to study the structures, their immunogenic properties as vaccines, and their capability to produce specific neutralization antibodies. Materials and Methods: TAX and HBZ sequences were chosen from the NCBI-nucleotide database, then designed as human Fc chimers and cloned into Pichia pastoris. Produced proteins were purified by HiTrap affinity chromatography and subcutaneously injected into rabbits. Rabbit Abs were purified by batch chromatography, and their neutralization activities for the HTLV-1-infected MT-2 cell line were assessed. Furthermore, the protective abilities of recombinant proteins were evaluated in Tax or HBZ immunized rabbits by MT-2 cell line inoculation and measurement of HTLV-1-proviral load. Results: Specific Abs against Tax and HBZ can eliminate 2 million MT-2 cells in 1/1000 dilution in vitro. In challenging assays, the immunization of the animals using Tax or HBZ had no protective activity as HTLV-1 PVL was still positive. Conclusion: The result suggests that recombinant TAX and HBZ: hFcγ1 proteins can produce a proper humoral immune response. Therefore, they could be considered a passive immunotherapy source for HTLV-1-associated diseases, while total TAX and HBZ proteins are unsuitable as HTLV-1 vaccine candidates.
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Human T lymphotropic virus (HTLV-I) is a retrovirus that has been recognized as a causative agent of two crucidal diseases, HTLV-I-Associated Myelopathy/Tropical Spastic Paraparesis (HAM/TSP) and Adult T cell Leukemia-Lymphoma (ATLL). The virus not only induces those diseases in a small proportion of HTLV-I carriers (3-5%) but also it is associated with other diseases such as HTLV-I-Associated Arthropathy (HAAP), Cutaneous T Cell Lymphoma (CTCL), Graves' disease, uveitis, polymyositis, chronic respiratory diseases, lymphadenitis and dermatitis. Furthermore, HTLV related and accelerated disorders were more investigated, and the factors that might implicate in the development or progression of diseases have been discussed. We founded 13 categories of non-associated disease in studies such as Reproductive Disorders, Coronary Artery Disease (CAD), non -ATLL lymphoma, Co-infection, non-HAM/TSP neurological associated disease, non ATLL cutaneous associated disease, Autoimmune-Inflammatory related disease, Kidney disease, Liver disease, Respiratory disease, TB disease and Thyroid disease. With regard to the reviewed studies suggested HTLV-I disorders can divide into three manifests; related, accelerated and associated disease. However, interaction between HTLV-I infection and host immune response was complicated and vague. Some infectious patients indicated the involvement of inflammatory response of immune system, but in other individuals function of anti-inflammatory elements was observed. For a better understanding of this classification, more systematic studies should be designed and need to provide a global network to control and prevent HTLV affiliated diseases.
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Doenças Autoimunes , Infecções por Deltaretrovirus , Vírus Linfotrópico T Tipo 1 Humano , Leucemia-Linfoma de Células T do Adulto , Paraparesia Espástica Tropical , Adulto , Humanos , Paraparesia Espástica Tropical/complicações , Pele/patologiaRESUMO
OBJECTIVES: Human T cell leukaemia virus type 1 (HTLV-1) is associated with adult T cell leukaemia (ATL), a malignant lymphoproliferative disease that infects CD4 T cells. It is not clear why the majority of HTLV-1-infected individuals remain asymptomatic carries (ACs) and a minority develop ATL. Cellular immune response has a critical role in ATL and destroys malignant and HTLV-1-infected cells. Perforin and granzyme have important functional roles in apoptosis and destruction of infected cells. In the present study we examined the role of perforin and granzyme in ATL patients and ACs. MATERIALS AND METHODS: Peripheral blood mononuclear cells (PBMCs) were isolated from ATL patients and ACs by using Ficoll-hypaque density centrifugation. RNA was extracted and cDNA was synthesized. A real-time PCR TaqMan method was designed and optimized for evaluation of perforin, granzyme, tax, and HBZ gene expression. HTLV-1 proviral load (PVL) was quantified in patients with ATL and ACs. RESULTS: The mRNA expression of tax and HBZ was significantly higher in ATL patients than ACs (P=0.011 and P=0.0001,respectively). The HTLV-1 PVL was higher in ATL patients compared to with AC group (P=0.015). There was a significant increase in perforin gene expression in ACs compared with ATL patients (P=0.002). Furthermore, the expression of granzyme was also higher in ACs compared with ATL patients, and significant differences were observed between the two groups (P=0.036). CONCLUSION: Low expression of perforin and granzyme in ATL patients seems to influence the efficiency of CTL function and destruction of HTLV-1-infected cells, which might contribute to the disease pathogenesis.
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BACKGROUND: Adult T-cell leukemia/lymphoma (ATLL) is a lymphoproliferative disorder of HTLV-1-host interactions in infected TCD4+ cells. In this study, the HTLV-1 proviral load (PVL) and HBZ as viral elements and AKT1, BAD, FOXP3, RORγt and IFNλ3 as the host factors were investigated. METHODS: The study was conducted in ATLLs, HTLV-1-associated myelopathy/tropical spastic paraparesis patients (HAM/TSPs) and HTLV-1-asympthomatic carriers (ACs). The DNA and mRNA from peripheral blood mononuclear cells were extracted for gene expression assessments via qRT-PCR, TaqMan assay, and then confirmed by western blotting. RESULTS: As it was expected, the HTLV-1-PVL were higher in ATLLs than ACs (P = 0.002) and HAM/TSP (P = 0.041). The HBZ expression in ATLL (101.76 ± 61.3) was radically higher than in ACs (0.12 ± 0.05) and HAM/TSP (0.01 ± 0.1) (P = 0.001). Furthermore, the AKT1 expression in ATLLs (13.52 ± 4.78) was higher than ACs (1.17 ± 0.27) (P = 0.05) and HAM/TSPs (0.72 ± 0.49) (P = 0.008). However, BAD expression in ATLL was slightly higher than ACs and HAM/TSPs and not significant. The FOXP3 in ATLLs (41.02 ± 24.2) was more than ACs (1.44 ± 1) (P = 0.007) and HAM/TSP (0.45 ± 0.15) (P = 0.01). However, RORγt in ATLLs (27.43 ± 14.8) was higher than ACs (1.05 ± 0.32) (P = 0.02) but not HAM/TSPs. Finally, the IFNλ3 expression between ATLLs (31.92 ± 26.02) and ACs (1.46 ± 0.63) (P = 0.01) and ACs and HAM/TSPs (680.62 ± 674.6) (P = 0.02) were statistically different, but not between ATLLs and HAM/TSPs. CONCLUSIONS: The present and our previous study demonstrated that HTLV-1-PVL and HBZ and host AKT1 and Rad 51 are novel candidates for molecular targeting therapy of ATLL. However, high level of RORγt may inhibit Th1 response and complicated in ATLL progressions.
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Fatores de Transcrição de Zíper de Leucina Básica/genética , Infecções por HTLV-I/genética , Vírus Linfotrópico T Tipo 1 Humano/genética , Leucemia-Linfoma de Células T do Adulto/genética , Proteínas dos Retroviridae/genética , Adulto , Feminino , Fatores de Transcrição Forkhead/genética , Regulação Neoplásica da Expressão Gênica , Regulação Viral da Expressão Gênica/genética , Infecções por HTLV-I/sangue , Infecções por HTLV-I/patologia , Infecções por HTLV-I/virologia , Interações Hospedeiro-Patógeno/genética , Vírus Linfotrópico T Tipo 1 Humano/patogenicidade , Humanos , Leucemia-Linfoma de Células T do Adulto/sangue , Leucemia-Linfoma de Células T do Adulto/patologia , Leucemia-Linfoma de Células T do Adulto/virologia , Leucócitos Mononucleares/metabolismo , Leucócitos Mononucleares/patologia , Masculino , Pessoa de Meia-Idade , Membro 3 do Grupo F da Subfamília 1 de Receptores Nucleares/genética , Paraparesia Espástica Tropical/sangue , Paraparesia Espástica Tropical/genética , Paraparesia Espástica Tropical/patologia , Paraparesia Espástica Tropical/virologia , Proteínas Proto-Oncogênicas c-akt/genética , RNA Mensageiro/genética , Rad51 Recombinase/genética , Células Th1 , Carga Viral , Proteína de Morte Celular Associada a bcl/genéticaRESUMO
BACKGROUND: Adult T-cell leukemia/lymphoma (ATLL) is caused by human T-cell lymphotropic virus type-1 (HTLV-1). HTLV-1 oncogenes can induce malignancy through controlled gene expression of cell cycle checkpoints in the host cell. HTLV-I genes play a pivotal role in overriding cell cycle checkpoints and deregulate cellular division. In this study, we aimed to determine and compare the HTLV-1 proviral load and the gene expression levels of cyclin-dependent kinase-2 (CDK2), CDK4, p53, and retinoblastoma (Rb) in ATLL and carrier groups. METHODS: A total of twenty-five ATLL patients (12 females and 13 males) and 21 asymptomatic carriers (10 females and 11 males) were included in this study. TaqMan real-time polymerase chain reaction assay was used for evaluation of proviral load and gene expression levels of CDK2, CDK4, p53, and Rb. Statistical analysis was used to compare proviral load and gene expression levels between two groups, using SPSS version 18. RESULTS: The mean scores of the HTLV-1 proviral load in the ATLL patients and healthy carriers were 13067.20±6400.41 and 345.79±78.80 copies/104 cells, respectively (P=0.000). There was a significant correlation between the gene expression levels of CDK2 and CDK4 (P=0.01) in the ATLL group. CONCLUSION: Our findings demonstrated a significant difference between the ATLL patients and healthy carriers regarding the rate of proviral load and the gene expression levels of p53 and CDK4; accordingly, proviral load and expression levels of these genes may be useful in the assessment of disease progression and prediction of HTLV-1 infection outcomes.
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BACKGROUND: Adult T-cell leukemia/lymphoma (ATLL) is an aggressive malignancy with very poor prognosis and short survival, caused by the human T-lymphotropic virus type-1 (HTLV-1). The HTLV-1 biomarkers trans-activator x (TAX) and HTLV-1 basic leucine zipper factor (HBZ) are main oncogenes and life-threatening elements. This study aimed to assess the role of the TAX and HBZ genes and HTLV-1 proviral load (PVL) in the survival of patients with ATLL. METHODS: Forty-three HTLV-1-infected individuals, including 18 asymptomatic carriers (AC) and 25 ATLL patients (ATLL), were evaluated between 2011 and 2015. The mRNA expression of TAX and HBZ and the HTLV-1 PVL were measured by quantitative PCR. RESULTS: Significant differences in the mean expression levels of TAX and HBZ were observed between the two study groups (ATLL and AC, P=0.014 and P=0.000, respectively). In addition, the ATLL group showed a significantly higher PVL than AC (P=0.000). There was a significant negative relationship between PVL and survival among all study groups (P=0.047). CONCLUSION: The HTLV-1 PVL and expression of TAX and HBZ were higher in the ATLL group than in the AC group. Moreover, a higher PVL was associated with shorter survival time among all ATLL subjects. Therefore, measurement of PVL, TAX, and HBZ may be beneficial for monitoring and predicting HTLV-1-infection outcomes, and PVL may be useful for prognosis assessment of ATLL patients. This research demonstrates the possible correlation between these virological markers and survival in ATLL patients.
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Adult T cell leukemia/lymphoma (ATLL) is a life-threatening malignancy of HTLV-1 infected Th lymphocytes. In the present study host-virus interactions were investigated by assessment of HTLV-1 proviral load (PVL) and host gene expression. A cross-sectional study was carried out on 18 ATLL, 10 HAM/TSP patients and 18 HTLV-1 asymptomatic carriers (ACs). DNA and mRNA of the peripheral blood mononuclear cells were extracted for PVL and LAT, BIM, c-FOS and RAD51 gene expression measurement using qRT-PCR. The mean PVL in ATLL patients was 11,430 ± 3770 copies/104 which was statistically higher than ACs, 530 ± 119 copies/104, (p < 0.001). The expression of BIM, and c-FOS in ATLL patients were higher than HTLV-1 ACs; however, there were no statistically significant differences. The expression of RAD51 as an essential player on DNA repair showed around 160 times increase in ATLL group (166 ± 95) compared to ACs (1.04 ± 0.34) which is statistically significant (p < 0.001). Interestingly, there was a positive correlation between RAD51 expression and HTLV-PVL. The expression of LAT as a central adaptor in TCR signaling interestingly was around 36 times higher in ATLL group than ACs (ATLL; 41.33 ± 19.91 vs. ACs; 1.15 ± 0.22, p < 0.001). This finding showed that TCR signaling pathway mainly provides the growth factors for transformed cells. Furthermore, the overexpression of RAD51 which has been induced in HTLV-1 infected cells as a consequence of virus replication is not able to overcome the DNA damage toward cell transformation.
Assuntos
Proteínas Adaptadoras de Transdução de Sinal/análise , Proteína 11 Semelhante a Bcl-2/análise , Vírus Linfotrópico T Tipo 1 Humano/isolamento & purificação , Leucemia-Linfoma de Células T do Adulto/patologia , Proteínas de Membrana/análise , Proteínas Proto-Oncogênicas c-fos/análise , Rad51 Recombinase/análise , Carga Viral , Adulto , Estudos Transversais , Feminino , Perfilação da Expressão Gênica , Humanos , Leucemia-Linfoma de Células T do Adulto/virologia , Leucócitos Mononucleares/patologia , Leucócitos Mononucleares/virologia , Masculino , Pessoa de Meia-Idade , Provírus/isolamento & purificaçãoRESUMO
The main aim of this study was to evaluate the expression of intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and inducible nitric oxide synthase (iNOS) as host factors, and proviral load as the viral parameter, in adult T-cell leukemia/lymphoma (ATLL) individuals and healthy carrier (HC(s)) groups. Peripheral blood mononuclear cells (PBMC) from ATLL patients (n = 17) and HC subjects (as the control group, n = 17) were evaluated using real-time PCR to determine the levels of HTLV-1 proviral load and mRNA expression of ICAM, VCAM-1, and iNOS. ICAM-1 was significantly lower in ATLL patients than in control subjects. Although the expression of VCAM-1 was higher in ATLL individuals, there was no significant difference between the studied groups. In addition, no iNOS expression was found in ATLL patients, when compared to the HCs subjects, while ATLL patients demonstrated a higher level of proviral load when compared to the control group. Considering the importance of ICAM-1 in facilitating immune recognition of infected cells, it is posited that reduction of ICAM-1 expression is a unique strategy for circumventing appropriate immune responses that are mediated by different accessory proteins. Additionally, as the viral regulatory protein Tax and the NF-κB pathway play pivotal roles in expression of iNOS, lack of the latter in ATLL patients may be related to the level of Tax expression, disruption of the NF-κB pathway, or the occurrence of epigenetical mechanisms in the human iNOS promoter. Further studies are recommended to gain a better understanding of the interaction between host and viral factors in HTLV-1 pathogenesis and to identify a possible therapeutic target for ATLL.
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Vírus Linfotrópico T Tipo 1 Humano/fisiologia , Molécula 1 de Adesão Intercelular/genética , Leucemia-Linfoma de Células T do Adulto/genética , Óxido Nítrico Sintase Tipo II/genética , Molécula 1 de Adesão de Célula Vascular/genética , Adulto , Feminino , Vírus Linfotrópico T Tipo 1 Humano/genética , Humanos , Molécula 1 de Adesão Intercelular/metabolismo , Leucemia-Linfoma de Células T do Adulto/metabolismo , Leucemia-Linfoma de Células T do Adulto/virologia , Leucócitos Mononucleares/metabolismo , Leucócitos Mononucleares/virologia , Masculino , Pessoa de Meia-Idade , Óxido Nítrico Sintase Tipo II/metabolismo , Regiões Promotoras Genéticas , Molécula 1 de Adesão de Célula Vascular/metabolismoRESUMO
Human T-cell lymphotropic virus 1 (HTLV-1) is associated with two progressive diseases: HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) and adult T-cell leukemia/lymphoma (ATLL). Although HTLV-1 proviral load (PVL) has been introduced as a risk factor for these diseases' progression, it is not sufficient on its own to yield an accurate estimation of the outcome of the infection. In the present study, PVL and HTLV-1 basic leucine zipper factor (HBZ) expression level as viral factors, and IFN λ3 as a host factor, were evaluated in HAM/TSP patients and HTLV-1 asymptomatic carriers (ACs). During 2014-2015, 12 HAM/TSP patients and 18 ACs who had been referred to the HTLV-1 Clinic, Ghaem Hospital, Mashhad University of Medical Sciences (MUMS), Mashhad, Iran, were enrolled in this study. Peripheral blood mononuclear cells (PBMCs) were isolated and the DNA and mRNA were extracted for quantification of HBZ, IFN λ3 expression, and PVL using real-time PCR (TaqMan method). Although the PVL was higher in the HAM/TSP group, with a 94% confidence interval, there were no considerable differences in terms of HBZ mRNA and PVL between ACs and HAM patients. IFN λ3 expression in the HAM/TSP group was significantly higher than in the ACs (P = 0.02). To the best of our knowledge, no study has evaluated the expression level of IFN λ3 in HTLV-1 positive patients. The immune response against HTLV-1 viral antigens and virulent factors will therefore further refine our knowledge of interactions between the virus and host in the pathogenesis of HTLV-1-related disorders. The virus PVL and the host IFN λ3 can be used as pathogenic factors of HTLV-1 infected patients at risk of HAM/TSP manifestation. J. Med. Virol. 89:1102-1107, 2017. © 2016 Wiley Periodicals, Inc.
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Fatores de Transcrição de Zíper de Leucina Básica/biossíntese , Infecções por HTLV-I/virologia , Vírus Linfotrópico T Tipo 1 Humano/patogenicidade , Interleucinas/biossíntese , Provírus/patogenicidade , Proteínas dos Retroviridae/biossíntese , Carga Viral , Adulto , Fatores de Transcrição de Zíper de Leucina Básica/genética , DNA Viral/análise , Feminino , Perfilação da Expressão Gênica , Infecções por HTLV-I/patologia , Interações Hospedeiro-Patógeno , Vírus Linfotrópico T Tipo 1 Humano/isolamento & purificação , Humanos , Interferons , Interleucinas/genética , Irã (Geográfico) , Leucócitos Mononucleares/virologia , Masculino , Pessoa de Meia-Idade , Provírus/isolamento & purificação , RNA Mensageiro/análise , Reação em Cadeia da Polimerase em Tempo Real , Proteínas dos Retroviridae/genéticaRESUMO
During a review of patients admitted with thromboangiitis obliterans (TAO), there was evidence of normochromic normocytic anemia and abrupt changes in hemoglobin (Hgb) levels in patients with several hospital admissions. Therefore, the evidence of hemolytic anemia was evaluated based on 37 banked plasma samples taken from Caucasian male TAO patients during disease exacerbation between 2012 and 2014. The patients' hospital records, including clinical manifestations and complete blood count, were evaluated. The following tests were performed on all samples: indirect antiglobulin test (IAT), C-reactive protein (CRP), high-sensitivity CRP (hsCRP), lactate dehydrogenase (LDH), haptoglobin, indirect bilirubin, d-aspartate aminotransferase (AST), and d-alanine aminotransferase (ALT). The mean age of the patients was 40 ± 7 years. Two patients underwent below-knee amputation. The mean hospital-documented Hgb of the patients was 12.9 ± 2.6 g/dL. CRP and IAT were positive in 75.6 and 70.2% of the samples, respectively. The tests and corresponding results were as follows: hsCRP, 14.07 ± 2.37 µg/mL; LDH, 2,552 ± 315 u/L; haptoglobin, 2.27 ± 1.1 g/L; indirect bilirubin, 0.09 ± 0.04 mg/dL; AST, 67 ± 7 u/L; and ALT, 26 ± 3 u/L. There was a significant inverse correlation between hsCRP and hospital-documented Hgb level (p = 0.03). Anemia with the positive IAT in most of the samples, high LDH and AST, and normal ALT are suggestive of hemolytic anemia. Normal indirect bilirubin is consistent with intravascular hemolysis. The positive CRP and elevated haptoglobin levels could be due to systemic inflammation in TAO. However, it is not known if an autoantigen or an infectious antigen is responsible for TAO systemic inflammation and induction hemolytic anemia. As such, the underlying mechanism of anemia in TAO could be part of the footprint of its main etiology.
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OBJECTIVE(S): Human T Lymphocyte Virus Type one (HTLV-I) is a retrovirus that infects about 10-20 million people worldwide. Khorasan province in Iran is an endemic area. The majority of HTLV-I-infected individuals sustain healthy carriers but small proportion of infected population developed two progressive diseases: HAM/TSP and ATL. The proviral load could be a virological marker for disease monitoring, therefore in the present study HTLV-I proviral load has been evaluated in ATL and compared to HAM/TSP and healthy carriers. MATERIALS AND METHODS: In this case series study, 47 HTLV-I infected individuals including 13 ATL, 23 HAM/TSP and 11 asymptomatic subjects were studied. Peripheral blood mononuclear cells (PBMCs) were investigated for presence of HTLV-I DNA provirus by PCR using LTR and Tax fragments. Then in infected subjects, HTLV-I proviral load was measured using real time PCR TaqMan method. RESULTS: The average age of patients in ATL was 52±8, in HAM/TSP 45.52±15.17 and in carrier's 38.65±14.9 years which differences were not statistically significant. The analysis of data showed a significant difference in mean WBC among study groups (ATL vs HAM/TSP and carriers P=0.0001). Moreover, mean HTLV-I proviral load was 11967.2 ± 5078, 409 ± 71.3 and 373.6 ± 143.3 in ATL, HAM/TSP and Healthy Carriers, respectively. The highest HTLV-I proviral load was measured in ATL group that had a significant correlation with WBC count (R=0.495, P=0.001). The proviral load variations between study groups was strongly significant (ATL vs carrier P=0.0001; ATL vs HAM/TSP P= 0.0001 and HAM/TSP vs carriers P< 0.05). Conclusion : The present study demonstrated that HTLV-I proviral load was higher in ATL group in comparison with HAM/TSP and healthy carriers. Therefore, HTLV-I proviral load is a prognostic factor for development of HTLV-I associated diseases and can be used as a monitoring marker for the efficiency of therapeutic regime.