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The Lancet. Infectious Diseases Jan 2020Human T-cell lymphotropic virus type 1 (HTLV-1) is a human retrovirus that causes a lifelong infection. Several diseases, including an aggressive form of leukaemia, have... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Human T-cell lymphotropic virus type 1 (HTLV-1) is a human retrovirus that causes a lifelong infection. Several diseases, including an aggressive form of leukaemia, have been designated as associated with HTLV-1, whereby having HTLV-1 is a necessary condition for diagnosis. Beyond these diseases, there is uncertainty about other health effects of HTLV-1. We aimed to synthesise evidence from epidemiological studies on associations between health outcomes and HTLV-1.
METHODS
For this systematic review and meta-analysis, we searched Embase, MEDLINE, MEDLINE In-Process, and Global Health for publications from their inception to July, 2018. We included cohort, case-control, and controlled cross-sectional studies that compared mortality or morbidity between people with and without HTLV-1. We excluded studies of psychiatric conditions, of symptoms or clinical findings only, of people who had undergone blood transfusion or organ transplant, and of population groups defined by a behavioural characteristic putting them at increased risk of co-infection with another virus. We extracted the risk estimates (relative risks [RRs] or odds ratios [ORs]) that reflected the greatest degree of control for potential confounders. We did a random-effects meta-analysis for groups of effect estimates where case ascertainment methods, age groups, and confounders were similar, presenting pooled estimates with 95% CIs and prediction intervals.
FINDINGS
Of the 3318 identified studies, 39 met the inclusion criteria, examining 42 clinical conditions between them. The adjusted risk of death due to any cause was higher in people with HTLV-1 when compared with HTLV-1-negative counterparts (RR 1·57, 95% CI 1·37-1·80). From meta-analysis, HTLV-1 was associated with increased odds of seborrheic dermatitis (OR 3·95, 95% CI 1·99-7·81), Sjogren's syndrome (3·25, 1·85-5·70), and, inversely, with lower relative risk of gastric cancer (RR 0·45, 0·28-0·71). There were a further 14 diseases with significant associations or substantially elevated risk with HTLV-1 from single studies (eczema [children]; bronchiectasis, bronchitis and bronchiolitis [analysed together]; asthma [males]; fibromyalgia; rheumatoid arthritis; arthritis; tuberculosis; kidney and bladder infections; dermatophytosis; community acquired pneumonia; strongyloides hyperinfection syndrome; liver cancer; lymphoma other than adult T-cell leukaemia-lymphoma; and cervical cancer).
INTERPRETATION
There is a broad range of diseases studied in association with HTLV-1. However, the elevated risk for death among people with HTLV-1 is not explained by available studies of morbidity. Many of the diseases shown to be associated with HTLV-1 are not fatal, and those that are (eg, leukaemia) occur too rarely to account for the observed mortality effect. There are substantial research gaps in relation to HTLV-1 and cardiovascular, cerebrovascular, and metabolic disease. The burden of disease associated with the virus might be broader than generally recognised.
FUNDING
Commonwealth Department of Health, Australia.
Topics: Arthritis, Rheumatoid; Bronchitis; Eczema; Epidemiologic Studies; HTLV-I Infections; Human T-lymphotropic virus 1; Humans
PubMed: 31648940
DOI: 10.1016/S1473-3099(19)30402-5 -
Tropical Medicine & International... Nov 2019Human T-cell lymphotropic virus type 1 (HTLV-1), the causative agent of adult T-cell leukaemia/lymphoma (ATL) and HTLV-1-associated myelopathy/tropical spastic... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Human T-cell lymphotropic virus type 1 (HTLV-1), the causative agent of adult T-cell leukaemia/lymphoma (ATL) and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP), is endemic in sub-Saharan Africa (SSA) and poses a high morbidity and mortality risk. Its prevalence in the general population is poorly understood. The potential for prevention motivated us to do a systematic review and meta-analysis of population-based studies to estimate the prevalence of HTLV-1 in SSA.
METHODS
A comprehensive, no-limit search was conducted in EMBASE, PubMed, Web of Science and the Cochrane Library from their inception dates to March 2019. Population-based studies presenting data on HTLV-1 in sub-Saharan Africa were included. Pooled prevalence was estimated using a random-effects meta-analysis.
RESULTS
A total of 21 studies were included, representing 42 297 participants. The pooled HTLV-1 seroprevalence was 3.19% (95% CI 2.36-4.12%) with variations across year of study. Prevalence of HTLV-1 positively correlated with year of study (β = 0.0036, P = 0.007). Participants from Central, Western and Southern Africa had a seroprevalence of 4.16% (95% CI 2.43-6.31%), 2.66% (95% CI 1.80-3.68%) and 1.56% (95% CI 0.48-3.15%), respectively.
CONCLUSIONS
Our findings suggest that HTLV-1 infection is a public health concern in SSA and highlight the need to implement effective preventive programmes and interventions aimed at reducing the burden of this common yet neglected infection.
Topics: Africa South of the Sahara; HTLV-I Infections; Human T-lymphotropic virus 1; Humans; Paraparesis, Tropical Spastic; Prevalence; Seroepidemiologic Studies
PubMed: 31465629
DOI: 10.1111/tmi.13305 -
The American Journal of Tropical... Oct 2019Human T-cell lymphotropic virus type 1 (HTLV-1) imposes a substantial disease burden in sub-Saharan Africa (SSA), which is arguably the world's largest endemic area for... (Meta-Analysis)
Meta-Analysis
Prevalence and Molecular Epidemiology of Human T-Lymphotropic Virus Type 1 among Women Attending Antenatal Clinics in Sub-Saharan Africa: A Systematic Review and Meta-Analysis.
Human T-cell lymphotropic virus type 1 (HTLV-1) imposes a substantial disease burden in sub-Saharan Africa (SSA), which is arguably the world's largest endemic area for HTLV-1. Evidence that mother-to-child transmission persists as a major mode of transmission in SSA prompted us to estimate the pooled prevalence of HTLV-1 among pregnant women throughout the region. We systematically reviewed databases including EMBASE, MEDLINE, Web of Science, and the Cochrane Database of Systemic Reviews from their inception to November 2018. We selected studies with data on HTLV-1 prevalence among pregnant women in SSA. A random effect meta-analysis was conducted on all eligible data and heterogeneity was assessed through subgroup analyses. A total of 18 studies, covering 14,079 pregnant women, were selected. The evidence base was high to moderate in quality. The pooled prevalence, per 100 women, of the 18 studies that screened HTLV-1 was 1.67 (95% CI: 1.00-2.50), a figure that masks regional variations. In Western, Central, Southern, and Eastern Africa, the numbers were 2.34 (1.68-3.09), 2.00 (0.75-3.79), 0.30 (0.10-0.57), and 0.00 (0.00-0.21), respectively. The prevalence of HTLV-1 infection among pregnant women in SSA, especially in Western and Central Africa, strengthens the case for action to implement routine screening of pregnant women for HTLV-1. Rigorous studies using confirmatory testing and molecular analysis would characterize more accurately the prevalence of this infection, consolidate the evidence base, and further guide beneficial interventions.
Topics: Africa South of the Sahara; Female; HTLV-I Infections; Human T-lymphotropic virus 1; Humans; Infectious Disease Transmission, Vertical; Molecular Epidemiology; Pregnancy; Prevalence
PubMed: 31407658
DOI: 10.4269/ajtmh.19-0182 -
Expert Review of Hematology Aug 2019: The southeastern coastal area of China has a high prevalence of HTLV-1 infection among blood donors. However, the estimation of HTLV-1 prevalence on a national and... (Meta-Analysis)
Meta-Analysis
: The southeastern coastal area of China has a high prevalence of HTLV-1 infection among blood donors. However, the estimation of HTLV-1 prevalence on a national and regional level is little known. The aim of this study is to understand and explore the estimation of HTLV-1 infection prevalence among blood donors on a national and regional level in mainland China by using a systematic review and meta-analysis. : All relevant publications of the past two decades (1998-2017), which were reported in both English and Chinese languages, were adopted and systematically assessed. The estimation of prevalence and its 95% confidence interval (CI) at the level of provinces/municipalities and overall were estimated using meta-analysis method. : From the 327 studies searched, 60 met the inclusion criteria. These were from 18 provinces and four municipalities and included 1,420,079 blood donors. The overall estimation of the HTLV-1 prevalence in blood donors was 0.169‰, and its 95% CI was 0.121‰-0.240‰. : A disproportionate distribution of HTLV-1 infection among blood donors in different provinces/municipalities regarding its prevalence has been reported. This study recommends developing appropriate HTLV-1 screening strategies of blood donors in various regions of China considering regional prevalence, and cost-effectiveness.
Topics: Blood Donors; China; HTLV-I Infections; Human T-lymphotropic virus 1; Humans; Prevalence
PubMed: 31220418
DOI: 10.1080/17474086.2019.1632703 -
Biology of Blood and Marrow... Aug 2019Human T cell lymphotropic virus type 1 (HTLV1)-associated adult T cell leukemia/lymphoma (ATLL) is an aggressive malignant disorder. Intensive conventional chemotherapy... (Meta-Analysis)
Meta-Analysis
Efficacy of Allogeneic Hematopoietic Cell Transplantation in Human T Cell Lymphotropic Virus Type 1-Associated Adult T Cell Leukemia/Lymphoma: Results of a Systematic Review/Meta-Analysis.
Human T cell lymphotropic virus type 1 (HTLV1)-associated adult T cell leukemia/lymphoma (ATLL) is an aggressive malignant disorder. Intensive conventional chemotherapy regimens and autologous hematopoietic cell transplantation (HCT) have failed to improve outcomes in ATLL. Allogeneic HCT (allo-HCT) is commonly offered as front-line consolidation despite lack of randomized controlled trials. We performed a comprehensive search of the medical literature using PubMed/Medline, EMBASE, and Cochrane reviews on September 10, 2018. We extracted data on clinical outcomes related to benefits (complete response [CR], overall survival [OS], and progression-free survival [PFS]) and harms (relapse and nonrelapse mortality [NRM]), independently by 2 authors. Our search strategy identified a total of 801 references. Nineteen studies (n = 2446 patients) were included in the systematic review; however, only 18 studies (n = 1767 patients) were included in the meta-analysis. Reduced intensity conditioning regimens were more commonly prescribed (52%). Bone marrow (50%) and peripheral blood (40%) were more frequently used as stem cell source. The pooled post-allografting CR, OS, and PFS rates were 73% (95% confidence interval [CI], 57% to 87%), 40% (95% CI, 33% to 46%), and 37% (95% CI, 27% to 48%), respectively. Pooled relapse and NRM rates were 36% (95% CI, 28% to 43%) and 29% (95% CI, 21% to 37%), respectively. The heterogeneity among the included studies was generally high. These results support the use of allo-HCT as an effective treatment for patients with ATLL, yielding pooled OS rates of 40%, but relapse still occurs in over one-third of cases. Future studies should evaluate strategies to help reduce relapse in patients with ATLL undergoing allo-HCT.
Topics: Allografts; Disease-Free Survival; Female; HTLV-I Infections; Hematopoietic Stem Cell Transplantation; Human T-lymphotropic virus 1; Humans; Incidence; Leukemia-Lymphoma, Adult T-Cell; Male; Randomized Controlled Trials as Topic; Survival Rate; Transplantation Conditioning
PubMed: 31132453
DOI: 10.1016/j.bbmt.2019.05.027 -
Vox Sanguinis Jul 2019Human T-cell lymphotropic viruses (HTLV) 1 and 2 are endemic in sub-Saharan Africa (SSA), transfusion-transmissible and causally linked to various severe diseases.... (Meta-Analysis)
Meta-Analysis
BACKGROUND AND OBJECTIVE
Human T-cell lymphotropic viruses (HTLV) 1 and 2 are endemic in sub-Saharan Africa (SSA), transfusion-transmissible and causally linked to various severe diseases. However, even in SSA countries with moderate to high endemicity, routine blood donor screening for HTLV is rarely, if ever, performed. Information on seroprevalence is limited. The aim of this review is to establish the prevalence of HTLV-1 and HTLV-1/2 among blood donors in sub-Saharan Africa.
MATERIALS AND METHODS
We systematically reviewed databases including EMBASE, MEDLINE and the Cochrane database library from their inception to June 2018. Studies presenting data on HTLV prevalence among blood donors in sub-Saharan Africa were included. A random-effect meta-analysis was conducted on all eligible studies.
RESULTS
A total of 25 studies were included, representing 74 119 blood donors, of whom over 80% (61 002) were only tested for HTLV-1. The evidence base was high and moderate in quality. The pooled prevalence of the 17 studies that screened only for HTLV-1 and the nine studies that screened for HTLV-1/2 was 0·68 (95% CI: 0·29-1·60) and 1·11 (95% CI: 0·47-2·59) per 100 blood donors, respectively.
CONCLUSION
The prevalence of HTLV-1 infection among blood donors is relatively low. The current review is intended to inform debates and decisions about best practices to prevent transfusion-transmitted HTLV in sub-Saharan Africa. Further work is required to determine the risk of infections by transfusion and the cost-effectiveness of any new measures such as routine screening.
Topics: Africa South of the Sahara; Blood Donors; Female; HTLV-I Infections; Human T-lymphotropic virus 1; Humans; Male; Mass Screening; Seroepidemiologic Studies
PubMed: 30972789
DOI: 10.1111/vox.12779 -
Journal of Cellular Physiology Aug 2019Human T-lymphotropic virus Type 1 (HTLV-1) is a retrovirus that is endemic in some regions of the world. It is known to cause several diseases like adult T-cell leukemia...
BACKGROUND
Human T-lymphotropic virus Type 1 (HTLV-1) is a retrovirus that is endemic in some regions of the world. It is known to cause several diseases like adult T-cell leukemia (ATL) and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). Serology and molecular methods have been used to detect this virus. Of these, enzyme-linked immunosorbent assay (ELISA) is used as a primary screening method and this is usually followed by western blotting (WB) and polymerase chain reaction (PCR) methods as confirmatory tests. We conducted a systematic review of the different techniques used in the diagnosis of HTLV-1 infection.
MATERIALS AND METHODS
Our search was limited to original papers in the English language from 2010 to 2018 using several databases including Pubmed, Scopus, Google Scholar, Iranmedex, and Scientific Information Database. A manual search of references provided in the included papers was also performed.
RESULTS
Of 101 electronically searched citations, 43 met the inclusion criteria. ELISA is commonly used for qualitative and screening detection, and WB and PCR techniques are used to confirm infection.
CONCLUSION
Among all the reported methods for detection of HTLV-1, only serological and molecular tests are used as the most common technical assays for HTLV-1. The ELISA assay, without a confirmatory test, has several limitations and affect the accuracy of the results. Owing to the prevalence of HTLV-1 and limitations of the current detection methods, further evaluation of the accuracy of these methods is needed. There are new opportunities for applying novel technological advances in microfluidics, biosensors, and lab-on-a-chip systems to perform HTLV-1 diagnostics.
Topics: Biosensing Techniques; Blotting, Western; Enzyme-Linked Immunosorbent Assay; Human T-lymphotropic virus 1; Humans; Leukemia-Lymphoma, Adult T-Cell; Molecular Diagnostic Techniques; Paraparesis, Tropical Spastic; Polymerase Chain Reaction
PubMed: 30633358
DOI: 10.1002/jcp.28087 -
The Brazilian Journal of Infectious... 2018Human T-lymphotropic viruses (HTLV) are Deltaretroviruses that infect millions of individuals worldwide via the same transmission routes as HIV. With the aim of exposing... (Review)
Review
Human T-lymphotropic viruses (HTLV) are Deltaretroviruses that infect millions of individuals worldwide via the same transmission routes as HIV. With the aim of exposing the possible re-emergence of HTLV in West Africa since discovery, a systematic review was carried out, focusing on the distribution of the virus types and significance of frequent indeterminate reports, while highlighting the need for mandatory routine blood screening. Capturing relevant data from discovery till date, sources searched were Google Scholar, CrossRef, NCBI (PubMed), MEDLINE, Research Gate, Mendeley, abstracts of Conferences and Proceedings, organization websites and reference lists of selected papers. A total of 2626 references were initially retrieved using search terms: Worldwide prevalence of HTLV, HTLV in Africa, HTLV in West Africa, HTLV subtypes, HTLV 3 and 4 in Africa, HTLV of African origin, HTLV seroindeterminate results, Spread of HTLV. These references were rigorously trimmed down to 76. Although evidence shows that HTLV is still endemic in the region, West Africa lacks recent epidemiological prevalence data. Thorough investigations are needed to ascertain the true cause of indeterminate Western Blot results. It is imperative that routine screening for HTLVs be mandated in West African health care facilities.
Topics: Africa, Western; Deltaretrovirus; Deltaretrovirus Infections; Female; Humans; Male; Prevalence; Risk Factors; Seroepidemiologic Studies
PubMed: 29879426
DOI: 10.1016/j.bjid.2018.05.003 -
Journal of Tropical Pediatrics Apr 2018Human T-cell lymphotropic virus type 1 (HTLV-1) is endemic in some regions and its vertical transmission occurs mainly through breastfeeding. About 10% of carriers...
Human T-cell lymphotropic virus type 1 (HTLV-1) is endemic in some regions and its vertical transmission occurs mainly through breastfeeding. About 10% of carriers develop associated diseases including HTLV-1 associated myelopathy/tropical spastic paraparesis (HAM/TSP), adult T-cell leukemia/lymphoma (ATL) and infectious dermatitis associated with HTLV-1 (IDH). We searched for available case reports of early-onset HAM/TSP and ATL to evaluate demographic and disease aspects in infantile-juvenile patients. In the reviewed literature, 27 HAM/TSP and 31 ATL cases were found. In almost all of them, the most likely route of transmission was through breastfeeding. ATL is rarely reported, notwithstanding it may be underestimated because T-cell lymphomas are not investigated for HTLV-1 infection in this age group. IDH was frequently associated with HAM/TSP. The investigation of HTLV-1 infection in pregnant women is an important matter of public health and should be mandatory in endemic countries.
Topics: Adolescent; Adult; Child; Female; Human T-lymphotropic virus 1; Humans; Infectious Disease Transmission, Vertical; Leukemia-Lymphoma, Adult T-Cell; Male; Paraparesis, Tropical Spastic; Pregnancy; Young Adult
PubMed: 28582585
DOI: 10.1093/tropej/fmx039 -
International Journal of STD & AIDS Mar 2017Adult T-cell leukemia/lymphoma (ATL) is caused by the human T-cell lymphotropic virus type 1 (HTLV-1) which is endemic in countries of Caribbean and Central and South... (Review)
Review
Adult T-cell leukemia/lymphoma (ATL) is caused by the human T-cell lymphotropic virus type 1 (HTLV-1) which is endemic in countries of Caribbean and Central and South America. We performed a systematic search and review to identify publications on ATL in these countries to verify if this disease was getting recognition in these regions as well as the characteristics of the observed cases. The median age of 49.4 years was lower than that referred to in Japan. According to our findings in most Brazilian states and in some other countries, ATL is not being recognized and should be strongly considered in the differential diagnosis of T-cell leukemias/lymphomas. Failure to identify these cases may be due to the unsystematic realization of serology for HTLV-1 and phenotypic identification of non-Hodgkin lymphomas that may result from lack of resources. Detection of ATL cases has been more feasible with cooperation from foreign research centers. A huge effort should be made to improve the surveillance system for ATL diagnosis in most of the South- and Central-American and Caribbean countries, and this attitude should be embraced by public organs to support health professionals in this important task.
Topics: Adolescent; Adult; Aged; Aged, 80 and over; Caribbean Region; Central America; Female; HTLV-I Infections; Human T-lymphotropic virus 1; Humans; Leukemia-Lymphoma, Adult T-Cell; Lymphoma, Non-Hodgkin; Male; Middle Aged; South America; Young Adult
PubMed: 28178905
DOI: 10.1177/0956462416684461