HUMAN T-LYMPHOTROPIC VIRUS 1 (HTLV-1) AND HUMAN T-LYMPHOTROPIC VIRUS 2 (HTLV-2): GEOGRAPHICAL RESEARCH TRENDS AND COLLABORATION NETWORKS (1989-2012)

Effectiveness assessment of a home-based exercise intervention in mitigating HTLV-1 associated disabilities: A validation study

To evaluate the effectiveness of a home exercise program called Home Exercise Booklet for People Living with Human T Lymphotropic Virus 1 (HTLV-1). This is a methodological study of content validation with expert judges. A questionnaire with a Likert scale was applied, containing 16 items referring to the content domain. Descriptive statistics were used to obtain the content validity index. In total, 46 judges participated, 24 physiotherapists (PG) and 22 professionals from other health areas specializing in methodological studies and HTLV-1 (EG). In the validation process, each evaluator judged the technology and scored their considerations. In the end, we obtained the following results for the Content Validity Index (CVI): PG CVI: 94.3%, GE CVI: 93.4%. Although the index was sufficient to consider the technology validated, modifications were made to the second and final version of the booklet, considering the judges' observations and suggestions, which we consider relevant. The technology proved to be valid for use with the target audience. The development and validation of this product provides support to help prevent functional decline in people living with HTLV-1; standardize guidelines for physiotherapy professionals who monitor these issues; start a home exercise program aimed at other comorbidities; open the possibility of creating and validating home exercise programs with other comorbidities.

Human T-lymphotropic virus 2 (HTLV-2) prevalence of blood donors in the state of Pará, Brazil

INTRODUCTION

The present study had the objective to describe the molecular prevalence and epidemiological aspects of the human T-lymphotropic virus 2 (HTLV-2) infection in the blood donor population of the Pará state.

METHODS

The present study is a descriptive, retrospective, and cross-sectional review of epidemiological, serological, and molecular data on inapt blood donors in the State Center for Hematology and Hemotherapy from January 2015 to December 2021. The data were digitalized to create a database using the Statistical Package for Social Sciences program. The prevalence of HTLV-2 was calculated based on the total number of donations during the study period. Descriptive frequency was used to analyze the qualitative data.

RESULTS

A total of 665,568 blood donations were made. Out of these, 1884 (0.2%) samples presented serological detection to HTLV and further were evaluated using molecular confirmatory tests. Out of these, 36 samples were positive for HTLV-2 using qPCR Taqman assay based on pol gene region (0.005%). The HTLV-2 was found to be more prevalent in women (63.9%); aged between 39 and 59 years (55.6%); residents of the metropolitan region of Belém (80.6%); with self-declared race as brown (80.6%); individuals who had completed high school (58.6%); and first-time donors (58.3%) CONCLUSION: The present study identified the presence of HTLV-2 (1 HTLV-2 case/20,000 donations; 0.005%) in the specific population of blood donors in Pará state. These findings can contribute to the existing literature on the subject both for specific population groups under study and for understanding the prevalence of HTLV-2 in the general population.

Research on HTLV-1 and HTLV-2 in Latin America and the Caribbean over the last ten years

Worldwide, Human T-lymphtropic virus-1 and 2 (HTLV-1 and 2) infects approximately more than 10 million people, mostly occurring in hyperendemic areas such as the region of Latin America and the Caribbean (LAC). A comprehensive bibliographic exploration of original articles published on the Web of Science Core Collection database over the last 10 years was done. A bibliometric analysis was performed using the bibliometrix package in RStudio and VOSviewer. A total of 519 articles published in 194 journals were identified along the 10 years studied. In 2012 the peak number of publications was identified and the average number of citations per document was 1.33. Galvao-Castro B was the author with the greatest number of publications. Aids Research and Human Retroviruses was the most productive journal, and the study by Bangham CRM was the most cited. Brazil was the country with most corresponding authors that had the most publications and the most significant number of total citations. Infections and HTLV-1 were the most used keywords. In conclusion, according to the current quantitative analysis, there is a need for more significant promotion of research on HTLV-1 and 2 among the scientific community of LAC.

Spread of Human T-Lymphotropic Virus 1 and 2 Among Relatives of People Who Use Illicit Drugs in Northern Brazil

The human T-lymphotropic virus 1 (HTLV-1) and 2 (HTLV-2) can be transmitted between humans by mechanisms associated with horizontal and vertical routes. Recently, high prevalence rates and levels of genetic diversity for HTLV-1 and HTLV-2 were detected among people who use illicit drugs (PWUDs) in the Brazilian state of Pará. None of the PWUDs with HTLV-1 or HTLV-2 were aware of their carrier condition of the retrovirus, and they ability to spread it to their family group, sexual partners, and other contacts. Thus, this study evaluated the presence of HTLV-1 and HTLV-2 in families of PWUDs in the state of Pará, in Northern Brazil. This descriptive study used convenience sampling and accessed 37 PWUDs and their respective families (n = 97) in 18 municipalities in the state of Pará, northern Brazil. All participants provided personal data and were tested for the presence of HTLV-1 and HTLV-2 using enzyme-linked immunosorbent assay and western blotting. HTLV positive samples were selected for Nested-PCR, and viral genotyping by nucleotide sequencing and phylogenetic analysis. HTLV-1 or HTLV-2 infections were detected in 15 families of PWUDs: 27 family members of PWUDs were infected with HTLV-1 (27.8%) and another 20 of them with HTLV-2 (20.6%). Subtypes 1a [subgroup A (54.5%)], 2b (20.5%), and 2c (25.0%) were detected. High horizontal (76.9%) and vertical (61.4%) transmission rates of HTLV were ascertained. Factors that facilitate the acquisition and transmission of HTLV-1 and HTLV-2 were reported by the participants, such as long-term relationships, unprotected sex, breastfeeding, and lack of knowledge about the condition of being a carrier of the retrovirus. Evidence indicates intrafamilial transmission of HTLV from PWUDs to members of their respective families. Key interventions should urgently be employed for the control and prevention of HTLV-1 and HTLV-2 to reduce the spread of this retrovirus in PWUDs and the general population in Northern Brazil and elsewhere.

Novel Genetic Constructs for Production of Recombinant HTLV-1/2 Antigens and Evaluation of Their Reactivity to Plasma Samples from HTLV-1-Infected Patients

Human T-cell leukemia virus type 1 (HTLV-1) can cause life-threatening diseases for which there are no effective treatments. Prevention of HTLV-1 infection requires massive testing of pregnant women, blood for transfusion, and organs for transplantation, as well as safe sex. In this context, serological assays are widely used for monitoring HTLV-1 infections. Despite the necessity for recombinant antigens to compose serological tests, there is little information available on procedures to produce recombinant HTLV-1/2 antigens for serological diagnostic purposes. In this work, we tested a series of genetic constructions to select those more amenable for production in bacterial systems. To overcome the constraints in expressing sections of viral envelope proteins in bacteria, we have used the p24 segment of the gag protein as a scaffold to display the immunogenic regions of gp46 and gp21. Nine recombinant antigenic proteins derived from HTLV-1 and five derived from HTLV-2 were successfully purified. The HTLV-1 antigens showed high efficiency in discriminating HTLV-positive samples from HTLV-negative samples using enzyme-linked immunosorbent assays. Interestingly, HTLV-1-positive samples showed a high level of cross-reaction with HTLV-2 antigens. This finding is explained by the high sequence conservation between the structural proteins of these two highly related viruses. In summary, the results presented in this work provide a detailed description of the methods used to produce recombinant HTLV-1 and HTLV-2 antigens, and they demonstrate that the HTLV-1 antigens show strong potential for serological diagnosis of HTLV-1 infections.

Interaction of perforin and granzyme B and HTLV-1 viral factors is associated with Adult T cell Leukemia development

Objective(s):

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.

From cut-points to key players in co-authorship networks: a case study in ventilator-associated pneumonia research

In co-authorship networks, some nodes play the key role of cut-point, facilitating the integration of other authors and favoring connectivity among different research communities. The present study uses bibliometric and network embeddedness indicators to analyze the scientific activity on ventilator-associated pneumonia and the roles of 17 research communities and 30 cut-points therein. In addition to fostering network connectivity and cohesion, cut-points are characterized by other differential features compared to other authors, including a much higher level of productivity and greater participation in leadership positions, higher betweenness values, lower clustering coefficients and higher levels of constraint. The cut-points identified have different characteristics in terms of the connectivity they facilitate between research communities: some cut-points have established weak intercommunity ties in the form of bridges with a single author from a different community; in other cases, they serve as gatekeepers due to their connection with different authors of a community that they link with their own; cut-points may also act as structural folds, that is, actors with an overlapping role between two cohesive communities. The cut-points present very diverse connectivity degrees, with some cut-points whose elimination would provoke severe network fragmentation and others who are responsible for linking far fewer external authors to their network. The cut-points that present both the main mechanisms for obtaining social capital—that is, filling structural holes and participating in cohesive network structures—can be considered key actors/players because their participation is crucial for ensuring both integration into the main research focus of some communities with high research performance and the overall cohesion of a co-authorship network.

Human T-lymphotropic virus 1 and 2 among people who used illicit drugs in the state of Pará, northern Brazil

People who used illicit drugs (PWUDs) represent an important population group for acquisition and viral dispersion. In Brazil, high rates of the human T lymphotropic virus 1 (HTLV-1) and 2 (HTLV-2) have been reported in epidemiological studies. However, the epidemiological scenario of HTLV-1/2 infections in PWUDs is still poorly understood. Thus, this cross-sectional study determined the prevalence, frequency of subtypes and factors associated with HTLV-1/2 infections among PWUDs in the Brazilian state of Pará, an area considered endemic for this virus and with poor health services. Among 826 PWUDs, 53 (6.4%) presented anti-HTLV-1/2 antibodies by EIA and 44 (5.3%) presented proviral DNA by PCR. HTLV-1 and HTLV-2 were detected in 25 (3.0%) and 19 (2.3%) PWUDs, respectively. Subtypes 1a (25/44), transcontinental (23/44) and Japanese subgroups (2/44), 2b (6/44) and 2c (13/44) were identified. Involvement in illicit/criminal activity, daily use of illicit drugs, illicit drug use over 12 years, unprotected sex with other PWUDs, changes in genitalia (including ulcers and wounds), and more than 12 sexual partners were associated with HTLV-1/2 in PWUDs. This high prevalence and intense circulation of subtypes and subgroups of HTLV-1/2 is very worrying, and indicate the need for urgent actions for its control, prevention and treatment.

A snapshot of pneumonia research activity and collaboration patterns (2001-2015): a global bibliometric analysis

BACKGROUND

This article describes a bibliometric review of the scientific production, geographical distribution, collaboration, impact, and subject area focus of pneumonia research indexed on the Web of Science over a 15-year period.

METHODS

We searched the Web of Science database using the Medical Subject Heading (MeSH) of "Pneumonia" from January 1, 2001 to December 31, 2015. The only document types we studied were original articles and reviews, analyzing descriptive indicators by five-year periods and the scientific production by country, adjusting for population, economic, and research-related parameters.

RESULTS

A total of 22,694 references were retrieved. The number of publications increased steadily over time, from 981 publications in 2001 to 1977 in 2015 (R² = 0.956). The most productive country was the USA (38.49%), followed by the UK (7.18%) and Japan (5.46%). Research production from China increased by more than 1000%. By geographical area, North America (42.08%) and Europe (40.79%) were most dominant. Scientific production in low- and middle-income countries more than tripled, although their overall contribution to the field remained limited (< 15%). Overall, 18.8% of papers were the result of an international collaboration, although this proportion was much higher in sub-Saharan Africa (46.08%) and South Asia (23.43%). According to the specific MeSH terms used, articles focused mainly on "Pneumonia, Bacterial" (19.99%), followed by "Pneumonia, Pneumococcal" (7.02%) and "Pneumonia, Ventilator-Associated" (6.79%).

CONCLUSIONS

Pneumonia research increased steadily over the 15-year study period, with Europe and North America leading scientific production. About a fifth of all papers reflected international collaborations, and these were most evident in papers from sub-Saharan Africa and South Asia.

Clinical and laboratory features of HTLV-I asymptomatic carriers and patients with HTLV-I-associated myelopathy/tropical spastic paraparesis from the Brazilian Amazon

Clinical and laboratory parameters including blood and cerebrospinal fluid (CSF) neopterin were investigated in human-T-lymphotropic-virus-type-I associated-myelopathy/tropical-spastic-paraparesis-HAM/TSP and in HTLV-I carriers. HAM/TSP (n = 11, 2 males/9 females, median age = 48 years), recently diagnosed HTLV-I carriers (n = 21, 15 females/6 males, median age = 44 years), healthy individuals (n = 20, 10 males/10 females, median age = 34.6 years) from the Brazilian Amazon (Manaus, Amazonas State) were investigated. Neopterin was measured (IBL ELISA Neopterin, Germany) in serum samples of all the participants, in CSF of 9 HAM/TSP patients as well as in 6 carriers. In HAM/TSP patients, CSF cell counts, protein and glucose were measured, the Osame’s motor-disability-score/OMDS was determined, and brain/spinal cord magnetic-resonance-imaging (MRI) was performed. HAM/TSP patients had normal CSF glucose, leukocyte counts; and normal protein levels predominated. Brain-MRI showed white-matter lesions in 7 out of 11 HAM/TSP patients. OMDS varied from 2-8: 9 were able to walk, 2 were wheel-chair-users. The median serum neopterin concentration in HAM/TSP patients was 6.6 nmol/ L; min. 2.8- max. 12.5 nmol/ L); was lower in carriers (4.3 nmol/L; min. 2.7- max. 7.2 nmol/ L) as well as in healthy participants (4.7 nmol/ L; min. 2.7- max. 8.0 nmol/ L) (p < 0.05). CSF neopterin concentrations in HAM/TSP patients were higher than in serum samples, and higher compared to carriers (p < 0.05). Carriers had similar serum-CSF neopterin concentrations compared to healthy participants. Variable clinical and laboratory profiles were seen in HAM/TSP patients, however our results support the neopterin measurement as a potential biomarker of disease activity.