High prevalence of HTLV-1 infection among Japanese immigrants in non-endemic area of Brazil

Determination of molecular epidemiologic pattern of human T-lymphotropic virus type 1 (HTLV-1) in Alborz province, Iran

Human T-cell lymphotropic virus type 1 (HTLV-1) is linked to two debilitating diseases, adult T-cell leukemia/lymphoma (ATLL) and HTLV-1 associated myelopathy tropical spastic paraparesis (HAM/TSP), which are prevalent in various parts of the world, including the Alborz province in Iran. Understanding the prevalence and evolutionary relationships of HTLV-1 infections in these endemic areas is of utmost importance. In the realm of phylogenetic studies, long terminal repeat (LTR) region of HTLV-1 stands out as highly conserved, yet more variable compared to other gene segments. Consequently, it is the primary focus for phylogenetic analyses. Additionally, trans-activator of transcription (Tax), an oncoprotein, holds a pivotal role in the regulation of gene expression. This cross-sectional study delved into the phylogenetic analysis of HTLV-1 among individuals in Alborz province of Iran. To confirm infection, we amplified partial sequence LTR (PLTR) and HTLV-1 bZIP factor (PHBZ). For phylogenetic analysis, we sequenced the full sequence LTR (FLTR) and full Tax sequence (FTax). The FLTR and FTax sequences underwent analysis using BioEdit, and phylogenetic trees were constructed using MEGA-X software. Out of the roughly 15,000 annual blood donors in Alborz, 19 samples tested positive for HTLV-1, indicating a 0.13% HTLV-1 positivity rate among blood donors. Furthermore, the HTLV-1 virus prevalent in the Alborz province belongs to subtype A (cosmopolitan) subgroup A. The findings revealed that while mutations were observed in both the LTR and Tax genes, they were not significant enough to bring about fundamental alterations. Despite positive selection detected in three Alborz isolates, it has not led to mutations affecting Tax function and virulence.

Human T-lymphotropic virus 1/2 infection among immigrants and refugees in Central Brazil, an emerging vulnerable population

Introduction

Migratory flows play a significant role in the spread of human T-lymphotropic virus 1/2 (HTLV-1/2). In the last decade, a substantial migration of individuals occurred from Haiti and Venezuela to Brazil. However, data on the prevalence of HTLV-1/2 infection among these international migrants in Brazil are scarce. This study describes the prevalence of this infection among immigrants and refugees in Central Brazil.

Methods

A cross-sectional study was conducted with 537 international migrants in the State of Goiás, Central Brazil. Participants were interviewed, and blood samples were collected. Serological screening for anti-HTLV-1/2 was performed using an enzyme-linked immunosorbent assay (ELISA; Murex HTLV-I + II, DiaSorin, Dartford, UK), and seropositive samples were submitted for confirmation by a line immunoassay (INNO-LIA HTLV I/II, Fujirebio, Europe N.V., Belgium).

Results

The majority of participants were males (54.4%), between 18 and 50 years old (78%; mean age: 29.1 years), self-declared black (55.1%), reported 1 to 12 years of formal education (70.9%), and were either Venezuelans (47.9%) or Haitians (39.7%). Additionally, 50.1% were immigrants, 49% were refugees, and five were Brazilian children (0.9%) born to Haitian immigrant parents. The overall prevalence of anti-HTLV-1/2 was 0.95% (95% CI: 0.31-2.28), with HTLV-1 at 0.19% and HTLV-2 at 0.76%. All seropositive individuals (n = 5) were refugees from Venezuela, resulting in a rate of 2.26% for anti-HTLV-1/2, HTLV-1 (0.45%) and HTLV-2 (1.81%) among Venezuelan refugees. Of the demographic and behavioral characteristics evaluated, unprotected sexual intercourse and having more than one sexual partner (≥2) in the previous 12 months were associated with HTLV-1/2 seropositivity among Venezuelans.

Conclusion

This study revealed, despite the low seroprevalence of HTLV-1/2 among international migrants in Central Brazil, evidence of HTLV-1 and HTLV-2 infections in Venezuelan refugees. In addition, their characteristics highlight that specific social and health programs should be implemented for these emergent and socially vulnerable migrant groups.

HTLV infection in blood donors from Mato Grosso do Sul state: a closer look at HTLV screening in Brazilian blood banks

Human T-lymphotropic virus (HTLV) infection has a worldwide distribution and currently, more than 2.5 million individuals have been infected in Brazil. The study aimed to investigate HTLV infection prevalence among blood donors in Mato Grosso do Sul, characterizing seroepidemiological profiles of HTLV-1/2 positive individuals and evaluating the blood bank's HTLV screening system. A cross-sectional survey was conducted among blood donors from Mato Grosso do Sul state (MS)-Central Brazil, between January to December 2021. The information was obtained from databases, samples from the collection of HEMOSUL, and active searching, with the completion of laboratory analyses. 35,278 blood donors were screened for anti-HTLV-1/2 by chemiluminescence immunoassay (CMIA). Among them, 78 were initially reactive for anti-HTLV-1/2 (2.21/1000). Out of 78, 67 returned to the blood center to collect a second sample for retesting with a second screening with CMIA. After confirmation, 8 samples were indeterminate, and 8 were confirmed as positive for HTLV antibodies. New tests were performed for the 8 positive samples, and 6 were confirmed as HTLV-1 infection (0.17/1,000), one as negative, and one as indeterminate. The present study describes the low prevalence of HTLV infection in blood donors from MS and contributes to the definition of the regional infection profile. The prevalence found in this study (0.017%-0.17/1000) shows to be a much lower value than the rates reported in other states in Brazil. We highlight the need for confirmatory testing for those seropositive donors in screening assays and the need for adequate counseling and patient management for those confirmed HTLV individuals.

Epidemiological and molecular evidence of intrafamilial transmission through sexual and vertical routes in Bahia, the state with the highest prevalence of HTLV-1 in Brazil

INTRODUCTION

Familial clustering of HTLV-1 and related diseases has been reported in Brazil. However, intrafamilial transmission of HTLV-1 based on molecular analysis has been studied only in a few communities of Japanese immigrants and African-Brazilians.

OBJECTIVE

To investigate the familial clustering of HTLV-1 infection and to determine the likely routes of transmission through epidemiological and genetic analyzes.

METHODS

Medical records of 1,759 HTLV-1+ patients from de the Center for HTLV in Salvador, Brazil, were evaluated to identify first-degree relatives previously tested for HTLV-1. Familial clustering was assumed if more than one member of the same family was HTLV-1+. LTR regions of HTLV-1 sequences were analyzed for the presence of intrafamilial polymorphisms. Family pedigrees were constructed and analyzed to infer the likely transmission routes of HTLV-1.

RESULTS

In 154 patients at least one other family member had tested positive for HTLV-1 (a total of 182 first-degree relatives). Of the 91 couples (182 individuals), 51.6% were breastfed, and 67.4% reported never using a condom. Of the 42 mother-child pairs, 23.8% had a child aged 13 years or younger; all mothers reported breastfeeding their babies. Pedigrees of families with 4 or more members suggests that vertical transmission is a likely mode of transmission in three families. Three families may have had both vertical and sexual transmission routes for HTLV-1. The genetic signatures of the LTR region of 8 families revealed 3 families with evidence of vertical transmission, another 3 families (spouses) with sexual transmission, and one family with both transmission routes. HTLV-1 sequences belonged to Cosmopolitan subtype HTLV-1a Transcontinental subgroup A.

CONCLUSION

Sexual and vertical transmission routes contribute to the intrafamilial spread of HTLV-1 in the state of Bahia.

Human T Cell Lymphotropic Virus Type 1 Global Prevalence Associated with the Human Development Index: Systematic Review with Meta-Analysis

In 2012, the number of people infected with human T cell lymphotropic virus type 1 (HTLV-1) was estimated to be 10 million worldwide. Prevalence varies according to geographic location, ethnic factors, sex, age, populations exposed to risk factors, income, and education, reaching countries with the worst socioeconomic scenarios. There is a need to determine the current global prevalence of HTLV-1 and examine its association with countries' human development index (HDI) to provide data for global health policy. Systematic review with meta-analysis is according to PRISMA 2020 recommendations. It was registered at PROSPERO, CRD42021223146. Prevalence or cross-sectional studies of HTLV-1 infection with at least 100 participants, screening, and confirmatory serologic testing were included. Studies with incomplete or unavailable results or with duplicate information were excluded. Data were selected by two independent investigators and analyzed using R software, a metapackage that generated the forest plots [95% confidence interval (CI)]. Heterogeneity was assessed using the I² statistic, and funnel plot asymmetry was assessed using Egger's test. Countries were compared using an HDI cutoff ≥0.8. Methodological quality was assessed using Joanna Briggs Institute (JBI) criteria. The overall prevalence of HTLV-1 infection was 0.91% (95% CI: 0.80-1.02, p < .0001) and was higher in low HDI countries [1.18% (95% CI: 1.03-1.34)] than in high HDI countries [0.41% (95% CI: 0.27-0.57)]. Prevalence varied according to the populations studied: it was higher in the general population [1.65% (95% CI: 1.08-2.34)] compared to pregnant women [0.34% (95% CI: 0.17-0.57)] and blood donors [0.04% (95% CI: 0.01-0.08)]. Consistently, prevalence for each population group was higher in low HDI countries than in high HDI countries. The worldwide prevalence of HTLV-1 infection is highly heterogeneous, with a global prevalence of 0.91%. In high HDI countries, the observed prevalence is approximately three times lower than in low HDI countries. In the general population, the observed prevalence is about 5 times higher than in pregnant women and 41 times higher than in blood donors.

HTLV infection in Brazil's second-largest indigenous reserve

Human T-lymphotropic viruses 1 and 2 (HTLV-1/2) have a worldwide distribution. HTLV-1 has been associated with several diseases, including an aggressive malignant disease known as adult T-cell leukemia/lymphoma and a chronic inflammatory neurological disease called HTLV-1-associated myelopathy, while HTLV-2 has not been definitively associated with diseases. HTLV-2 is most prevalent in specific groups such as injecting drug users and the indigenous population. In Brazil, most studies about HTLV in indigenous are carried out in indigenous communities from the north of the country. Mato Grosso do Sul (MS), Central Brazil, has the second-largest indigenous population in Brazil. However, there is no available data about HTLV infection in this group. We conducted the first investigation of HTLV-1/2 infection prevalence in the indigenous population from Jaguapiru and Bororó villages in Dourados City, MS, to provide the prevalence and molecular characterization of HTLV. For that, a total of 1875 indigenous participated in the study. All the serum samples were screened by an enzyme-linked immunosorbent assay commercial kit for the presence of anti-HTLV-1/2 antibodies. Positive samples were confirmed by HTLV-1/2 Western Blot assay. The HTLV-1 5’LTR region was detected by nested PCR amplification and sequenced by Sanger. Most of the study population declared belonging to Guarani-Kaiowá ethnicity (69.18%), 872 (46.51%), and 1003 (53.49%) were from Jaguapiru and Bororó villages, respectively. The median age of participants was 31 years, and 74.24% were females. Two individuals were detected with HTLV-1 (0.1%; CI 95% 0.1–0.2). The phylogenetic analysis revealed that isolates belong to the Cosmopolitan subtype and the Transcontinental subgroup (HTLV-1aA). The low HTLV-1 prevalence found in this study is similar to that observed among blood donors, and pregnant populations from Mato Grosso do Sul. The absence of HTLV-2 infection among these Brazilian indigenous communities would suggest a distinct behavior pattern from other indigenous populations in Brazil.

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.

Human T-Lymphotropic Virus-1/2 Infection in Central Brazil Prisons: A Multicenter Study

Human T-lymphotropic virus (HTLV) infection is endemic in some group populations. Prisoners are at high risk of acquiring HTLV infection mainly due to the environment of closed penal institutions, socioeconomic conditions, and risk behaviors. This study aimed to investigate the prevalence, the occurrence of new cases of HTLV infection after a 1-year follow-up, and circulating subtypes of HTLV-1 among prisoners from twelve closed prisons in Mato Grosso do Sul state, Central Brazil. A total of 1,507 prisoners were randomly enrolled in the cross-sectional study. Out of the 1,507 participants, 1,000 prisoners, susceptible to HTLV infection, were included in the prospective cohort study. In the cross-sectional study, serological evidence of HTLV infection was 0.4% (CI 95%: 0.1-0.7), tested for anti-HTLV antibodies by enzyme-linked immunosorbent assay (ELISA). Three samples were positive for HTLV-1, two samples were positive for HTLV-2, and 1 sample was indeterminate by the Western blot method. The presence of HTLV proviral DNA was detected in all positive samples by amplification of the HTLV tax gene through nested-PCR. Phylogenetic analysis showed that HTLV-1 samples belonged to the Cosmopolitan subtype Transcontinental subgroup. From a cohort of 1,000 individuals, no new case of HTLV infection was detected. Although the prevalence rate of HTLV infection found in this study was similar to that observed in the Brazilian general population, the lack of access to preventive interventions and harm reduction measures all contribute to increasing the risk of HTLV transmission and acquisition among this key and vulnerable population.

An overview of sequencing technology platforms applied to HTLV-1 studies: a systematic review

Human T-lymphotropic virus type 1 (HTLV-1) was the first human retrovirus described. The viral factors involved in the different clinical manifestations of infected individuals are still unknown, and in this sense, sequencing technologies can support viral genome studies, contributing to a better understanding of infection outcome. Currently, several sequencing technologies are available with different approaches. To understand the methodological advances in the HTLV-1 field, it is necessary to organize a synthesis by a rigorous review. This systematic literature review describes different technologies used to generate HTLV-1 sequences. The review follows the PRISMA guidelines, and the search for articles was performed in PubMed, Lilacs, Embase, and SciELO databases. From the 574 articles found in search, 62 were selected. The articles showed that, even with the emergence of new sequencing technologies, the traditional Sanger method continues to be the most commonly used methodology for generating HTLV-1 genome sequences. There are many questions that remain unanswered in the field of HTLV-1 research, and this reflects on the small number of studies using next-generation sequencing technologies, which could help address these gaps. The data compiled and analyzed here can help research on HTLV-1, assisting in the choice of sequencing technologies.

Human T-cell leukemia virus type 1 infection among Japanese immigrants and their descendants living in Southeast Brazil: A call for preventive and control responses

Human T-cell leukemia virus type 1 (HTLV-1) has worldwide distribution and is considered endemic in southwestern Japan. HTLV-1 infection has been associated with adult T-cell leukemia/lymphoma (ATL) and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) besides other diseases. This cross-sectional study aimed to investigate the prevalence, risk factors and molecular characterization of HTLV-1, among the world’s largest population of Japanese immigrants and their descendants outside of Japan, in São Paulo, Southeast Brazil, as well as to analyze the phylogenetic relationship among isolates of HTLV-1. From July to December 2017, 2,139 individuals from five Japanese associations were interviewed and submitted to blood collection. All serum samples were first tested for the presence of anti-HTLV-1/2 antibodies by ELISA and then peripheral blood from individuals with positive serological results were analyzed for the presence of HTLV-1 5’LTR proviral DNA. Partial sequencing of the 5’LTR region of HTLV-1 proviral DNA was performed by Sanger. The prevalence of HTLV-1 infection was 5.1% (CI 95%: 4.2–6.0). In the multiple logistic regression model, HTLV-1 infection was associated with age ≥ 45 years, female sex, being first and second-generation Japanese immigrants, and having sexual partners with history of blood transfusion. The phylogenetic analysis revealed that all HTLV-1 were classified as Cosmopolitan (1a) subtype. Of them, 47.8% were classified as Transcontinental (A) subgroup and 52.2% as belonging to the Japanese (B) subgroup. Although most HTLV-1-infected patients were asymptomatic (97.3%), blurred vision was associated with HTLV-1 infection. The high prevalence of HTLV-1 infection found in this studied population and especially the intra- and interfamily HTLV-1 transmission presents an urgent call for preventive and control responses of this infection in Brazil.

What is the prevalence of HTLV-1 among the largest world population of Japanese immigrants and their descendants outside Japan? There are approximately 1.5 million people of Japanese descent in Brazil and most of them living in São Paulo state, Southeast Brazil. The prevalence of HTLV-1 infection was 5.1% among 2,139 individuals from five Japanese associations in São Paulo. The prevalence of 5.1% (95% CI: 4.2–6.0) of HTLV-1 infection found in this study is higher than those observed in other studies conducted in HTLV-1 endemic areas and in specific groups at high risk from Brazil. Among HTLV-infected individuals, the majority (86.2%) were unaware of their HTLV diagnosis. The HTLV-1 infection was associated with the age ≥ 45 years, being the first and second generation of Japanese immigrants, and having sexual partners with a history of blood transfusion. Epidemiological data, along with molecular results also demonstrated high occurrence of similar sequences transmitted intra- and interfamily. The high prevalence of HTLV-1 infection found in this studied population presents an urgent call for preventive and control responses of this infection in Brazil.

Lymphotropic Viruses EBV, KSHV and HTLV in Latin America: Epidemiology and Associated Malignancies. A Literature-Based Study by the RIAL-CYTED

The Epstein-Barr virus (EBV), Kaposi sarcoma herpesvirus (KSHV) and human T-lymphotropic virus (HTLV-1) are lymphomagenic viruses with region-specific induced morbidity. The RIAL-CYTED aims to increase the knowledge of lymphoma in Latin America (LA), and, as such, we systematically analyzed the literature to better understand our risk for virus-induced lymphoma. We observed that high endemicity regions for certain lymphomas, e.g., Mexico and Peru, have a high incidence of EBV-positive lymphomas of T/NK cell origin. Peru also carries the highest frequency of EBV-positive classical Hodgkin lymphoma (HL) and EBV-positive diffuse large B cell lymphoma, not otherwise specified (NOS), than any other LA country. Adult T cell lymphoma is endemic to the North of Brazil and Chile. While only few cases of KSHV-positive lymphomas were found, in spite of the close correlation of Kaposi sarcoma and the prevalence of pathogenic types of KSHV. Both EBV-associated HL and Burkitt lymphoma mainly affect young children, unlike in developed countries, in which adolescents and young adults are the most affected, correlating with an early EBV seroconversion for LA population despite of lack of infectious mononucleosis symptoms. High endemicity of KSHV and HTLV infection was observed among Amerindian populations, with differences between Amazonian and Andean populations.

HTLV in South America: Origins of a silent ancient human infection

The description of the first human retrovirus, human T-lymphotropic virus 1 (HTLV-1), was soon associated with an aggressive lymphoma and a chronic inflammatory neurodegenerative disease. Later, other associated clinical manifestations were described, affecting diverse target organs in the human body and showing the enormous burden carried by the virus and the associated diseases. The epidemiology of HTLV-1 and HTLV-2 showed that they were largely distributed around the world, although it is possible to locate geographical areas with pockets of low and very high prevalence and incidence. Aboriginal Australians and indigenous peoples of Brazil are examples of the large spread of HTLV-1 and HTLV-2, respectively. The epidemiological link of both situations is their occurrence among isolated, epidemiologically closed or semi-closed communities. The origin of the viruses in South America shows two different branches with distinct timing of entry. HTLV-1 made its probable entrance in a more recent route through the east coast of Brazil at the beginning of the slave trade from the African continent, starting in the 16th century and lasting for more than 350 years. HTLV-2 followed the ancient route of human migration from the Asian continent, crossing the Behring Strait and then splitting in South America as the population became separated by the Andes Mountains. By that time, HTLV-2c probably arose and became isolated among the indigenous populations in the Brazilian Amazon. The study of epidemiologically closed communities of indigenous populations in Brazil allowed tracing the most likely route of entry, the generation of a new molecular subtype (HTLV-2c), the elucidation of the vertical transmission of HTLV-2, the intrafamilial aggregation of cases and the escape and spread of the virus to other areas in Brazil and abroad. Despite the burden and impact of both viruses, they are maintained as silent infections among human populations because 1, health authorities in most South American countries in which national surveillance is poor have little interest in the disease, 2, the information is commonly lost as indigenous groups do not have specific policies for HTLV and other sexually transmitted infections, and 3, health access is not feasible or properly delivered.

Use of synthetic oligonucleotides for determination of HTLV-1 proviral load by real-time PCR: a helpful alternative approach in the clinical management

AIMS

To evaluate the potential use of synthetic oligonucleotides as a standard curve for proviral load (PVL) of human T-cell leukaemia virus type 1 (HTLV-1) quantification in peripheral blood mononuclear cells (PBMC) of HTLV-1-infected individuals by quantitative real-time polymerase chain reaction (qPCR) analysis.

METHODS AND RESULTS

Synthetic oligonucleotides based on HTLV-1 genome were customized to use as a standard curve. Twelve anti-HTLV-1-positive samples with known HTLV-1 PVL, previously quantified by qPCR assay using TARL-2 cells as a conventional standard curve, were submitted to the new protocol. The proviral quantification levels had a high concordance with qPCR results using a conventional standard curve. The results demonstrate that the conventional standard curve can be replaced by a synthetic standard curve due to its ability to quantification based on the linearity and qPCR efficiency and similar results with a validated qPCR assay using a conventional standard curve.

CONCLUSIONS

Synthetic oligonucleotides standard curves could be a very useful tool on HTLV-1 diagnosis and absolute HTLV-1 PVL quantification.

SIGNIFICANCE AND IMPACT OF THE STUDY

HTLV-1 PVL determination using synthetic oligonucleotides standard curve by qPCR could be a helpful alternative for the laboratories that monitor infected patients as an important prognostic factor in HTLV-1-associated diseases progression. Also, it can decrease costs and overcome the biological limitations of the plasmid curve.

Human T-Cell Lymphotropic Virus Type 1 and associated diseases in Latin America

This narrative review, which is based on a systematic literature search following the PRISMA guidelines, provides a general overview of Human T-cell Lymphotropic Virus type 1 (HTLV-1) and associated diseases: Adult T-cell Leukaemia-Lymphoma (ATLL) and HTLV-1-Associated Myelopathy/Tropical Spastic Paraparesis (HAM/TSP) in Latin America, focusing on epidemiology and prevention. Using the published information on HTLV-1, ATLL and HAM/TSP prevalence, we present comprehensive and accurate maps and tables, and developed an algorithm to assist in the prevention of HTLV-1 transmission through breastfeeding while considering socio-economic status. Latin America is an interesting scenario to study HTLV-1 because of the diverse origin of its population. Apart from the expected high prevalence in inhabitants of African ancestry, the presence of endemic foci affecting indigenous populations is particularly striking. ATLL prevention is the biggest challenge in this field. Most ATLL cases are transmitted through breastfeeding; thus, prevention methods to avoid ATLL in endemic countries have to be focused on this. In view of the high inequality in most Latin American countries, reduction in breastfeeding duration, freezing/thawing and pasteurisation of breastmilk can be suitable interventions in poor settings, considering that avoiding the risk of malnutrition and infant mortality must be the priority.

Phylogeny of human T-lymphotropic virus-1 subtypes in Guinea-Bissau

Background

Human T-cell leukaemia/lymphoma virus type 1 (HTLV-1) was the first human retrovirus discovered and there is an estimate of 15-20 million infected worldwide. Endemic areas are Japan, West Africa, Central Africa, South America, the Caribbean, Middle East, Australia and the Pacific Islands. In Guinea-Bissau, adult HTLV-1 prevalence is 2-3%, and higher among HIV-infected patients.

Materials and methods

Blood samples were collected in a recent HIV/HTLV survey in Bissau, the capital of Guinea-Bissau. Initially, participants were tested for HTLV serologically. The p24 and LTR regions of the proviral genome were then attempted sequenced. Sequences were analysed phylogenetically and compared with reference sequences for HTLV-1.

Results

A total of 3% (78/2583) participants were positive on chemiluminesent assay, six additional samples came from another study. Of the 84 seropositive participants we successfully performed sequencing on samples, from 66 participants, 17 were positive for LTR only, one for p24 only and 48 for both. Sequences were in subgroup D of HTLV-1a cosmopolitan, while HTLV-1g was present in one participant.

Conclusion

HTLV-1a subgroup D and, to a lesser extent HTLV-1g, is present in Guinea-Bissau and sequences are very similar, especially within households. Presence of HTLV-1g indicates monkey-to-man zoonotic events and at least two circulating HTLV strains in Guinea-Bissau.

New sequences accession numbers

MG387979-MG388043 for LTR and MG388044-MG388092 for p24.

Human T cell lymphotropic virus type 1 infection among men who have sex with men in Central Brazil

Human T cell lymphotropic virus type 1 (HTLV-1) was the first retrovirus discovered in humans and is endemic in several parts of the world. Because of risk behaviors, mainly sexual, men who have sex with men (MSM) are at high risk of acquiring HTLV-1 infection. A cross-sectional study was performed to estimate the prevalence of HTLV-1 infection, to characterize genetically HTLV-1 sequences and to identify risk behaviors associated with this infection among MSM in Central Brazil. A total of 430 MSM were enrolled in this study and three were shown to be HTLV-1 infected, prevalence of 0.7% (95% confidence interval: 0.4–0.9). Phylogenetic analysis showed that all HTLV-1 positive samples belonged to Cosmopolitan subtype Transcontinental subgroup A. Although the prevalence rate of HTLV-1 infection found in this study was similar to that observed among Brazilian blood donors, additional HTLV-1 preventive interventions need to be further implemented because this population is engaged in high-risk sexual behavior.

HTLV-1/2 prevalence in two Amazonian communities

INTRODUCTION

The human T-cell lymphotropic virus type 1 (HTLV-1) is aetiologically linked to myelopathy/tropical spastic paraparesis (HAM/TSP) and adult T cell leukaemia (ATL) besides other less incident pathologies, while the type 2 has not been definitively linked to any diseases.

OBJECTIVES

To determine the HTLV-1/2 seroprevalence in two Brazilian communities in northern Brazil.

METHODS

In 2010 and 2015, HTLV-1/2 serological surveys were carried out in the Oiapoque county at the Brazilian border with French Guiana and in Santa Cruz do Arari, Marajó Island. Serum and breast-milk samples from 317 women (pregnant, lactating and non-pregnant non-lactating) resident in the Oiapoque county, together with serum samples from 217 females and 70 males living in Santa Cruz do Arari county, were twice screened by two distinct commercial immunoassay methods for antibodies to HTLV-1/2. Seroreactivity was confirmed by a commercial Western blot technique. Participants were interviewed for data concerning their health, socioeconomic and educational status.

RESULTS

None of the Oiapoque women, mostly young and descendants of migrants, had antibodies to HTLV-1/2, despite the high HTLV-1 prevalence in neighbouring French Guiana and Caribbean Islands, while five females and three males living in Santa Cruz do Arari county were HTLV-1 infected as confirmed by Western blot testing. In contrast, the Santa Cruz do Arari community lives in relative isolation and is descended mostly from black African people with high consanguinity.

CONCLUSION

Despite the proximity between Oiapoque and Santa Cruz do Arari counties, ethnic, age differences, community isolation and consanguinity may explain the distinct HTLV-1/2 epidemiology in these areas of northern Brazil.

Low prevalence of HTLV1/2 infection in a population of immigrants living in southern Italy

AIMS

To assess the prevalence of HTLV-1 and HTLV-2 infections in a cohort of immigrants living in southern Italy.

FINDINGS

We screened for antibody to HTLV-1/2 infection 1,498 consecutive immigrants born in endemic areas (sub-Saharan Africa or southern-Asia) by a commercial chemiluminescent microparticle immunoassay. If confirmed in a Western blot assay, which differentiates anti-HTLV-1 from anti-HTLV-2, the positive sera were tested for specific HTLV RNA by a home-made PCR. The immigrants investigated were more frequently males (89.05%), young (median age 26 years), with a low level of education (median schooling 6 years), born in sub-Saharan Africa (79.70%). They had been living in Italy for a median period of 5 months. Only one (0.07%) subject was anti-HTLV-1 -positive/HTLV-1 RNA-negative; he was an asymptomatic 27-year-old male from Nigeria with 6 years' schooling who stated unsafe sexual habits and unsafe injection therapy.

CONCLUSIONS

The data suggest screening for HTLV1 and HTLV-2 infections all blood donors to Italy from endemic countries at least on their first donation; however, a cost-effectiveness study is needed to clarify this topic.

Human T Cell Leukemia Virus Type 1: Persistence and Pathogenesis

Human T cell leukemia virus type 1 (HTLV-1), also known as human T lymphotropic virus type 1, was the first exogenous human retrovirus discovered. Unlike the distantly related lentivirus HIV-1, HTLV-1 causes disease in only 5-10% of infected people, depending on their ethnic origin. But whereas HIV-1 infection and the consequent diseases can be efficiently contained in most cases by antiretroviral drug treatment, there is no satisfactory treatment for the malignant or inflammatory diseases caused by HTLV-1. The purpose of the present article is to review recent advances in the understanding of the mechanisms by which the virus persists in vivo and causes disabling or fatal diseases.

Cytokine profile and proviral load among Japanese immigrants and non-Japanese infected with HTLV-1 in a non-endemic area of Brazil

The lifetime risk of HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) development differs among ethnic groups. To better understand these differences, this prospective cohort study was conducted to investigate the cytokine profile and the HTLV-1 proviral load (PVL) in Japanese and non-Japanese populations with HAM/TSP and asymptomatic carriers (ACs). The serum IL-2, IL-4, IL-6, IL-10, IL-17, TNF-α, and IFN-γ levels were quantified using the Cytometric Bead Array in 40 HTLV-1-infected patients (11 HAM/TSP and 29 ACs) and 18 healthy controls (HCs) in Brazil. Among ACs, 15 were Japanese descendants and 14 were non-Japanese. Of 11 patients with HAM/TSP, only one was a Japanese descendant. The HTLV-1 PVL was quantified by real-time PCR. The HTLV-1 PVL was 2.7-fold higher in HAM/TSP patients than ACs. Regardless of the clinical outcome, the PVL was significantly higher in patients younger than 60 years than older patients. The HAM/TSP and ACs had higher IL-10 serum concentrations than that of HCs. The ACs also showed higher IL-6 serum levels than those of HCs. According to age, the IL-10 and IL-6 levels were higher in ACs non-Japanese patients older than 60 years. HAM/TSP patients showed a positive correlation between IL-6 and IL-17 and a negative correlation between the PVL and IL-17 and IFN-γ. In the all ACs, a significant positive correlation was observed between IL-2 and IL-17 and a negative correlation was detected between IL-10 and TNF-α. Only 6.25% of the Japanese patients were symptomatic carriers, compared with 41.67% of the non-Japanese patients. In conclusion, this study showed that high levels of HTLV-1 PVL was intrinsicaly associated with the development of HAM/TSP. A higher HTLV-1 PVL and IL10 levels found in non-Japanese ACs over 60 years old, which compared with the Japanese group depicts that the ethnic background may interfere in the host immune status. More researches also need to be undertaken regarding the host genetic background to better understand the low frequency of HAM/TSP in Japanese HTLV-1-infected individuals.

Oral and Cutaneous Lymphomas other than Mycosis Fungoides and Sézary Syndrome in a Mexican Cohort: Recategorization and Evaluation of International Geographical Disparities

Background:

Nonmycosis fungoides/Sézary syndrome (non-MF/SS) primary cutaneous lymphomas (PCL) are currently categorized under the 2005-World Health Organization/European Organization for Research and Treatment of Cancer (WHO-EORTC) classification for PCL. These differ in behavior from secondary cutaneous lymphomas (SCL) and to lymphomas limited to the oral cavity (primary oral lymphomas [POL]) both categorized under the 2016-WHO classification for lymphoid neoplasms.

Aims:

This study aims to report the first series of non-MF/SS PCL, SCL, and POL in a Mexican cohort, examine the applicability of current classification systems and compare our findings with those from foreign cohorts.

Materials and Methods:

Eighteen non-MF/SS PCL, four SCL, and two POL with available tissue for morphology and immunophenotypic assessment were reclassified according to the 2005-WHO/EORTC and 2016-WHO classifications.

Results:

Non-MF/SS PCLs were primarily of T-cell origin (61%) where CD30+ lymphoproliferative disorders predominated, followed by Epstein–Barr virus-induced lymphomas, and peripheral T-cell lymphomas, not otherwise specified. Primary cutaneous B-cell lymphomas (BCL) were primarily of follicle center cell origin followed by postgerminal lymphomas of the diffuse large BCL variety.

Conclusions:

Most non-MF/SS PCL, SCL, and POL can be adequately categorized according to the 2005-WHO/EORTC and 2016-WHO classification systems, even when dealing with clinically atypical cases. The relative frequencies in our cohort hold closer similarities to Asian registries than from those of Europe/USA, supporting the concept of individual and/or racial susceptibility, and the notion of geographical variances in the rate of lymphomas. In particular, such disparity may arise from viral-induced lymphomas which might show partial geographical restriction.

Evaluation of human T-lymphotropic virus prevalence/co-infection rates for a four-year period in a non-metropolitan blood center in Southeast Brazil

INTRODUCTION

Human T-lymphotropic virus types 1/2 (HTLV-1/2) are distributed worldwide and are endemic in specific regions.

METHODS

Serological evaluation of the HTLV-1/2 prevalence and co-infection rate [human immunodeficiency virus (HIV), hepatitis B virus (HBV), hepatitis C virus (HCV), Chagas disease, and syphilis)] for 2011-2014 was performed with volunteer blood donors from the western part of São Paulo State.

RESULTS

Serrana and Araçatuba had higher HTLV seroprevalence rates (0.1%); while Franca, Olimpia, and Bebedouro had lower seroprevalences (0.04%). Co-infection (HBV and syphilis) was present in 12.3% of HTLV-infected blood donors.

CONCLUSIONS

Our findings provide data for the prevalence of HTLV in Brazil and demonstrate the importance of regional and global hemovigilance.