Integrative and Multidisciplinary Care for People Living With Human T-Cell Lymphotropic Virus in Bahia, Brazil: 20 Years of Experience

Infective dermatitis associated with human T-cell lymphotropic virus type-1, an underdiagnosed disease

Infective dermatitis associated with human T-cell lymphotropic virus type-1 (HTLV-1) (IDH) is a severe form of chronically infected eczema occurring in early childhood, although very rarely cases have been reported in adults. Most of the cases are from Jamaica and Brazil and occur in individuals with low socioeconomic status. IDH is always associated with refractory Staphylococcus aureus or beta-hemolytic Streptococcus infection of the skin and nasal vestibules. Patients with IDH may develop other even more severe HTLV-1-associated diseases, such as HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) of early or late appearance and adult T-cell leukemia/lymphoma. In the context of the Brazilian experience, it has been observed that 54% of IDH patients exhibit the juvenile form of HAM/TSP while the estimated incidence of adult HAM/TSP is 3%. As there are no curative treatments for HTLV-1 infection (or vaccines) or most of its associated diseases, prevention of infection is fundamental, mainly by vertical transmission, as it is responsible for the development of IDH, infantojuvenile HAM/TSP, and ATL. Public measures to reduce this transmission must be implemented urgently. Furthermore, it is recommended, mainly in HTLV-1 endemic areas, to search for HTLV-1 infection in all patients with infected eczema, even in adults.

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.

Prevalence and characteristics of HTLV-associated uveitis in patients from Bahia, an endemic area for HTLV - 1 in Brazil

BACKGROUND

HTLV-1-associated uveitis (HAU) is an inflammatory reaction of the choroid, retina, optic nerve and vitreous that can lead to vision impairment. The worldwide prevalence of HAU varies widely.

OBJECTIVE

To determine the prevalence of HAU in patients from Salvador, Bahia-Brazil, and describe uveitis type and associated symptoms.

METHODS

Cross-sectional analytical study to determine the prevalence of uveitis in HTLV-1-infected patients recruited in Bahia, Brazil, a region considered endemic for HTLV-1. Patients were enrolled at a local reference center for HTLV (infected) and at an outpatient ophthalmology clinic (noninfected group). All patients were examined by the same ophthalmologist following a single protocol. Prevalence ratios (PR) were calculated.

RESULTS

A total of 168 consecutively examined HTLV-1-infected patients and 410 noninfected patients (randomly selected) were included. Females predominated (82.1%) in the HTLV-1-infected group (versus 64.4% in the uninfected group) (p < 0.001). The mean age of infected and uninfected patients was 53.2 and 62.8 years, respectively (p < 0.001). The prevalence of uveitis in HTLV-1+ and HTLV-1- patients was 7.14% and 0.73%, respectively (PR = 9.76; 95CI%:2.79-34.15; p < 0.01). Bilateral intermediate uveitis, associated with symptoms including visual disturbances and floaters, was most commonly identified in the HTLV-1-infected patients, whereas unilateral anterior uveitis, in association with symptoms such as blurring and ocular pain, was more common in the uninfected group.

CONCLUSION

The prevalence of uveitis in patients with HTLV-1 was markedly higher than in uninfected subjects. HAU patients were mostly asymptomatic and exhibited bilateral presentation, with uveitis more frequently localized in the intermediate chamber.

HTLV-1 Proviral Load in Vaginal Fluid Correlates with Levels in Peripheral Blood Mononuclear Cells

BACKGROUND

The prevalence of human T-lymphotropic virus type-1 (HTLV-1) infection is higher in women, and sexual intercourse has been described as an important route of male-to-female transmission. The present study aimed to quantify HTLV-1 proviral load (PVL) in vaginal fluid, and to investigate correlations with PVL in peripheral blood mononuclear cells (PBMCs). In addition, cytopathological alterations and vaginal microbiota were evaluated.

METHODS

HTLV-1-infected women were consecutively recruited at a multidisciplinary center for HTLV patients in Salvador, Brazil. All women underwent gynecological examinations to obtain cervicovaginal fluid and venipuncture for blood collection. PVL, as measured by real-time quantitative polymerase chain reaction (RT-qPCR), was expressed as the number of copies of HTLV-1/10⁶ cells in blood and vaginal fluid samples. Light microscopy was used to assess cervicovaginal cytopathology and vaginal microbiota.

RESULTS

In the 56 included women (43 asymptomatic carriers and 13 diagnosed with HTLV-1-associated myelopathy/tropical spastic paraparesis-HAM/TSP), mean age was 35.9 (SD ± 7.2) years. PVL was higher in PBMCs (median: 23,264 copies/10⁶ cells; IQR: 6776-60,036) than in vaginal fluid (451.9 copies/10⁶ cells; IQR: 0-2490) (p < 0.0001). PVL in PBMCs was observed to correlate directly with PVL in vaginal fluid (R = 0.37, p = 0.006). PVL was detected in the vaginal fluid of 24 of 43 (55.8%) asymptomatic women compared to 12 of 13 (92.3%) HAM/TSP patients, p = 0.02. Cytopathologic analyses revealed no differences between women with detectable or undetectable PVL.

CONCLUSION

HTLV-1 proviral load is detectable in vaginal fluid and correlates directly with proviral load in peripheral blood. This finding suggests that sexual transmission of HTLV-1 from females to males may occur, as well as vertical transmission, particularly in the context of vaginal delivery.

Increasing horizontal transmission of human T-cell leukemia virus type 1 in adolescents and young adults in Japan

BACKGROUND

Human T-cell leukemia virus type 1 (HTLV-1) is a causative agent of the life-threatening diseases, adult T-cell leukemia/lymphoma and HTLV-1-associated myelopathy. Following implementation of antenatal screening in Japan, novel transmission of HTLV-1 in adolescent and adult generations is expected to replace vertical transmission as the main route for transmission.

OBJECTIVES

To obtain the current status of HTLV-1 horizontal infection and to assess the fluctuation of transmission occurring among adolescents and adults in Japan.

STUDY DESIGN

We followed-up 5,017,916 eligible repeat blood donors for 8 years from 2013 to 2021. We evaluated HTLV-1 transmission rate by age group (16-69 years-old), and calculated the total number of novel transmissions in Japan using demographic statistics published by the government of Japan.

RESULTS

We identified 457 seroconverters (men, 203; women, 254) in a total of 19,244,604 person-years during the study period. The number of seroconversions per 100,000 person-years was 1.54 for men and 4.21 for women. An increase in the number of novel infections was observed in both sexes in adolescent and young adult generations despite the health bias of blood donors.

CONCLUSIONS

We estimate that more than 2,800 new HTLV-1 infections occur annually in Japan. It is a serious concern that without immediate measures against new HTLV-1 infections, such as guideline formulation, an inclusion of HTLV as routine screening in sexual health services, an information campaign, and surveillance of the general population, novel HTLV-1 infection could continue to increase in Japan and be a source of global transmission.

Current Interventions to Prevent HTLV-1 Mother-to-Child Transmission and Their Effectiveness: A Systematic Review and Meta-Analysis

Human T lymphotropic virus 1 (HTLV-1) may be transmitted from mother to child and affects at least 5−10 million individuals worldwide, with severe consequences on health. Strategies to prevent transmission are important, as there is no treatment or vaccine. This systematic review aimed to identify interventions to prevent HTLV-1 mother-to-child transmission and to determine their effectiveness. Exclusive formula feeding, short-term breastfeeding, use of freeze−thaw milk, milk pasteurization, maternal and infant antiretroviral drugs, caesarean section, early clamping of umbilical cord, screening of milk donors and avoidance of cross-breastfeeding were identified as possible strategies. Avoidance of breastfeeding is an intervention that prevents 85% of transmissions. This strategy is recommended in Japan, Brazil, Colombia, Canada, Chile, Uruguay, the USA and some regions of French Guyana. Whilst breastfeeding for <3 months does not increase the risk of transmission compared to exclusive formula-feeding, concerns remain regarding the limited number of studies outside Japan, and the lack of information on women having higher risk of HTLV-1 transmission and on the ability of women to discontinue breastfeeding. Additional interventions are plausible, but data on their effectiveness are limited. The acceptance of interventions is high. These findings may guide healthcare professionals and support policymakers in implementing policies to avoid HTLV-1 mother-to-child transmission.