A Peruvian family with a high burden of HTLV-1-associated myelopathy/tropical spastic paraparesis

Potential neuroinvasive and neurotrophic properties of SARS-CoV-2 in pediatric patients: comparison of SARS-CoV-2 with non-segmented RNA viruses

The emerging severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is causing global health crises. Children can be infected, but are less likely to develop severe neurological abnormalities compared with adults. However, whether SARS-CoV-2 can directly cause neurological impairments in pediatric patients is not known. The possible evolutionary and molecular relationship between SARS-CoV-2 and non-segmented RNA viruses were examined with reference to neurological disorders in pediatric patients. SARS-CoV-2 shares similar functional domains with neuroinvasive and neurotropic RNA viruses. The Spike 1 (S1) receptor binding domain and the cleavage sites at S1/S2 boundary are less conserved compared with the S2 among coronaviruses.

Early-Onset HTLV-1-Associated Myelopathy/Tropical Spastic Paraparesis

Background: Vertical transmission of HTLV-1 could lead to the early development of HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). This significantly affects quality of life and increases morbimortality. Objective: To describe the epidemiological and clinical characteristics of patients with early-onset HAM/TSP, defined as disease onset before 20 years of age. Methods: This is a retrospective study from an HTLV-1 clinical cohort between 1989 and 2019. We searched for medical records of patients with (1) diagnosis of HTLV-1 infection using two ELISA and/or one Western blot, (2) clinical diagnosis of HAM/TSP by neurological assessment, and (3) HAM/TSP symptom-onset before 20 years of age. Results: A total of 38 cases were identified in the cohort; 25 were female (66%). The median age of onset was 14 years old. 31 (82%) cases had HTLV-1 testing done among family members; 22 out of 25 tested mothers (88%) were HTLV-1 positive. Most patients (27/34) were breastfed for more than one year. Disease progression measured through EDSS and IPEC-1 showed an upward trend towards worsening spasticity with 18 patients (47%) eventually requiring mobility aids. Conclusions: Cases of early-onset HAM/TSP are not of rare occurrence, which translates into many more years of dependency, the use of mobility aids, and increased overall morbidity.

Infección por virus HTLV-1/2 confirmada por serología y detección de provirus en pacientes ecuatorianos de paraparesis espástica tropical

Introduccion: La infección con el virus linfotrópico de células T humano (HTLV) de tipo 1 y 2 es endémica en América del Sur. Existen muy pocos reportes clínicos de este retrovirus en pacientes de Ecuador y nunca confirmaron la presencia del virus con el aislamiento o la detección de su ADN. Esta infección se encuentra desatendida por las autoridades de salud pública, sin que existan estudios epidemiológicos de prevalencia a nivel del país. Objetivos: Este estudio tiene como objetivo la detección de infección por HTLV -1/2 en individuos sintomáticos de paraparesis espástica tropical (TSP) utilizando por primera vez en Ecuador diagnóstico serológico y la detección del provirus por biología molecular.Diseño del estudio. Se tomaron muestras de nueve pacientes con un diagnóstico de mielopatía y sospechoso de TSP, que fueron analizadas para la detección del virus HTLV-1/2 usando tres metodologías: ELISA comercial, ensayo de inmunofluorescencia indirecta (IF) y PCR anidada. Resultados: Cinco de los 9 (55.5%) pacientes fueron positivos tanto para la prueba de ELISA como para IF y PCR anidada. Conclusión: La alta prevalencia de infección por HTLV-1/2 entre individuos sintomáticos de mielopatía muestra la endemicidad de este retrovirus en Ecuador, la asociación de HTLV-1/2 con TSP y la necesidad de implementar estrategias de control y prevención para evitar la diseminación de esta enfermedad infecciosa desatendida.

CD49d Is Upregulated in Circulating T Lymphocytes from HTLV-1-Infected Patients

INTRODUCTION

HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is a chronic progressive myelopathy associated with an inflammation of the central nervous system (CNS), being characterized by perivascular infiltration of inflammatory cells. HTLV-1-infected cells have the capacity to migrate through endothelial layers by enhancing adhesion receptor expression and corresponding ligands. T cells interact with the extracellular matrix via integrin receptors and these interactions affect both cell migration and proliferation. The importance of these interactions in retrovirus-induced diseases, however, remains less clear.

METHODS

Herein we studied the expression of 3 integrin alpha chains (CD49d, CD49e, and CD49f) on the membrane of T-cell subsets in patients infected by HTLV-1, both HAM/TSP patients and oligo/asymptomatic subjects who were asymptomatic or presented slight manifestations related to the virus infection.

RESULTS

We observed higher peripheral blood frequency of CD49dhiCD4+ and CD49dhiCD8+ T cells in HTLV-1-infected patients.

CONCLUSION

Our findings suggest that the increased expression of adhesion molecules, such as CD49d on T lymphocytes from HTLV-1-infected patients may contribute to the pathogenesis of the disease, in both oligo/asymptomatic and HAM/TSP-infected subjects. Accordingly, it is conceivable that there is a potential use of CD49d as target for a therapeutic approach aiming at blocking migration of activated T cells from HTLV-1-infected patients into the CNS, thus avoiding the progression to HAM/TSP.

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.

A high prevalence of human T-lymphotropic virus (HTLV 1/2) infection among Afro-descendants, Esmeraldas province, Ecuador - need for the implementation of surveys and control programs

Background: Infection with the Human T-cell lymphotropic virus (HTLV) type 1 and 2 is endemic in South America. Although there are reports of the presence of these retroviruses in Ecuador, the infection is usually neglected in healthcare settings and by public health authorities, and no actualized prevalence data are available.

Objectives: This cross-sectional study aimed to estimate, using for the first time to our knowledge in Ecuador immunological and molecular biology methodologies, the prevalence of HTLV-1/2 infection in asymptomatic individuals from a potentially high-risk population of Afro-Ecuadorians in the Province of Esmeraldas.

Study design: Two hundred and twenty-seven plasma samples from asymptomatic individuals were analyzed for the detection of the HTLV-1/2 virus with three methods: a commercial ELISA, an indirect immunofluorescence (IF) assay, and a nested-PCR.

Results: The overall prevalence of HTLV-1/2 antibodies in this population, as determined with an ELISA, was 11.0%. Both the IF assay and the nested-PCR confirmed a prevalence of 3.5%.

Conclusion: The high prevalence of HTLV-1/2 infection among the Afro-Ecuadorian population of Esmeraldas Province shows the need of the implementation of control and prevention interventions to overcome the further dissemination of the infection. To define the real problem of HTLV-1/2 infection in Ecuador, more prevalence studies have to be undertaken in other Afro-Ecuadorian populations and high-risk populations like the indigenous population of the Andes Mountains and the tropical Amazon region.