Clinical features of human T-lymphotropic virus type 1 uveitis: a long-term follow-up

Human T-cell Leukemia Virus Type 1 (HTLV-1)-induced Uveitis

Human T-cell leukemia virus type 1 (HTLV-1) is a human retrovirus that causes T-cell malignant diseases (adult T-cell leukemia/lymphoma) and HTLV-1-related non-malignant inflammatory diseases, such as HTLV-1 uveitis. Although the symptoms and signs of HTLV-1 uveitis are nonspecific, intermediate uveitis with various degrees of vitreous opacity is the most common clinical presentation. It can occur in one or both eyes and its onset is acute or subacute. Intraocular inflammation can be managed with topical and/or systemic corticosteroids; however, recurrence of uveitis is common. The visual prognosis is generally favorable, but a certain proportion of patients have a poor visual prognosis. Systemic complications of patients with HTLV-1 uveitis include Graves' disease and HTLV-1-associated myelopathy/tropical spastic paraparesis. This review describes the clinical characteristics, diagnosis, ocular manifestations, management, and immunopathogenic mechanisms of HTLV-1 uveitis.

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.

Safety of intraocular anti-VEGF antibody treatment under in vitro HTLV-1 infection

Introduction

HTLV-1 (human T-cell lymphotropic virus type 1) is a retrovirus that infects approximately 20 million people worldwide. Many diseases are caused by this virus, including HTLV-1-associated myelopathy, adult T-cell leukemia, and HTLV-1 uveitis. Intraocular anti-vascular endothelial growth factor (VEGF) antibody injection has been widely used in ophthalmology, and it is reportedly effective against age-related macular degeneration, complications of diabetic retinopathy, and retinal vein occlusions. HTLV-1 mimics VEGF₁₆₅, the predominant isoform of VEGF, to recruit neuropilin-1 and heparan sulfate proteoglycans. VEGF₁₆₅ is also a selective competitor of HTLV-1 entry. Here, we investigated the effects of an anti-VEGF antibody on ocular status under conditions of HTLV-1 infection in vitro.

Methods

We used MT2 and TL-Om1 cells as HTLV-1-infected cells and Jurkat cells as controls. Primary human retinal pigment epithelial cells (HRPEpiCs) and ARPE19 HRPEpiCs were used as ocular cells; MT2/TL-Om1/Jurkat cells and HRPEpiCs/ARPE19 cells were co-cultured to simulate the intraocular environment of HTLV-1-infected patients. Aflibercept was administered as an anti-VEGF antibody. To avoid possible T-cell adhesion, we lethally irradiated MT2/TL-Om1/Jurkat cells prior to the experiments.

Results

Anti-VEGF antibody treatment had no effect on activated NF-κB production, inflammatory cytokines, chemokines, HTLV-1 proviral load (PVL), or cell counts in the retinal pigment epithelium (RPE) under MT2 co-culture conditions. Under TL-Om1 co-culture conditions, anti-VEGF antibody treatment did not affect the production of activated NF-κB, chemokines, PVL, or cell counts, but production of the inflammatory cytokine IL-6 was increased. In addition, anti-VEGF treatment did not affect PVL in HTLV-1-infected T cells.

Conclusion

This preliminary in vitro assessment indicates that intraocular anti-VEGF antibody treatment for HTLV-1 infection does not exacerbate HTLV-1-related inflammation and thus may be safe for use.

Clinical course of HTLV-1 infection associated intermediate uveitis

OBJECTIVE

To describe the clinical features at presentation, delivered treatment and follow-up of a case series of human T-cell lymphotropic virus type 1 (HTLV-1) associated intermediate uveitis.

PATIENTS AND METHODS

Retrospective, descriptive and longitudinal study of patients with HTLV-1 associated intermediate uveitis treated at a reference ophthalmology facility in Lima, Peru, during the years 2012 to 2018.

RESULTS

A total of 18 patients (28 eyes) were included, the average age at presentation was 57.3 years, 66.6% were women, and the average follow-up time was 1,280 days. The most frequent symptoms were blurred or diminished vision (78.6%) and floaters (57.1%). Best corrected visual acuity was 20/40 or better in 53.6%. The mean initial intraocular pressure was 14.95 mmHg. Keratic precipitates were observed in 50% of eyes, 17.9% were of the stellate type. The most frequent treatment was periocular corticosteroid injections (53.6%). Complications such as epimacular membrane (50%), cataract (21.4%) and glaucoma (7.1%) occurred. At the end of follow-up, only 2 eyes lost one line of vision; the final best corrected visual acuity was 20/40 or better in 85.7%, and 20/70 or better in 96.4%. Patients with both eyes affected increased from 33% at presentation to 55.5%. The course of the disease was chronic in 60.7%.

CONCLUSION

HTLV-1 associated intermediate uveitis mainly occurred in patients in the second half of life, developing a chronic course and with good visual prognosis.

Clinical and Public Health Implications of Human T-Lymphotropic Virus Type 1 Infection

Human T-lymphotropic virus type 1 (HTLV-1) is estimated to affect 5 to 10 million people globally and can cause severe and potentially fatal disease, including adult T-cell leukemia/lymphoma (ATL) and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). The burden of HTLV-1 infection appears to be geographically concentrated, with high prevalence in discrete regions and populations. While most high-income countries have introduced HTLV-1 screening of blood donations, few other public health measures have been implemented to prevent infection or its consequences. Recent advocacy from concerned researchers, clinicians, and community members has emphasized the potential for improved prevention and management of HTLV-1 infection. Despite all that has been learned in the 4 decades following the discovery of HTLV-1, gaps in knowledge across clinical and public health aspects persist, impeding optimal control and prevention, as well as the development of policies and guidelines. Awareness of HTLV-1 among health care providers, communities, and affected individuals remains limited, even in countries of endemicity. This review provides a comprehensive overview on HTLV-1 epidemiology and on clinical and public health and highlights key areas for further research and collaboration to advance the health of people with and at risk of HTLV-1 infection.

Updates on HTLV-1 Uveitis

HTLV-1 uveitis (HU) is the third clinical entity to be designated as an HTLV-1-associated disease. Although HU is considered to be the second-most frequent HTLV-1-associated disease in Japan, information on HU is limited compared to that on adult T-cell leukemia/lymphoma (ATL) and HTLV-1-associated myelopathy (HAM). Recent studies have addressed several long-standing uncertainties about HU. HTLV-1-related diseases are known to be caused mainly through vertical transmission (mother-to-child transmission), but emerging HTLV-1 infection by horizontal transmission (such as sexual transmission) has become a major problem in metropolitan areas, such as Tokyo, Japan. Investigation in Tokyo showed that horizontal transmission of HTLV-1 was responsible for HU with severe and persistent ocular inflammation. The development of ATL and HAM is known to be related to a high provirus load and hence involves a long latency period. On the other hand, factors contributing to the development of HU are poorly understood. Recent investigations revealed that severe HU occurs against a background of Graves’ disease despite a low provirus load and short latency period. This review highlights the recent knowledge on HU and provides an update on the topic of HU in consideration of a recent nationwide survey.

Epidemiology of Viral Induced Anterior Uveitis

Purpose: Viral agents are the most common cause of infectious anterior uveitis worldwide. The purpose of this review is to analyze the frequency, gender and racial differences of viral anterior uveitis (VAU) in various populations.Methods: Systematized literature review of epidemiological reports of VAU cited in PubMed, EMBASE and the Cochrane Library database published until June 30th, 2020.Results: A total of 12 clinical studies on epidemiology of definite VAU and 36 clinical studies of presumed VAU were identified. Members of Herpesviridae family represent the most common causes of VAU. Other less frequently reported causes, such as rubella and endemic viruses (HTLV-1, Chikungunya, Dengue, Ebola, Zika virus) were also analyzed.Conclusion: HSV, VZV are prevalent worldwide. CMV is more frequent in Asia, and rubella in the West. However, due to globalization and air travel, HTLV-1, Chikungunya, Dengue and Ebola may become important causes of VAU across the world.

HTLV-1 in Ophthalmology

Human T-cell leukemia virus type 1 (HTLV-1) was the first retrovirus described as a causative agent for human disease. In the field of ophthalmology, a close relationship between HTLV-1 infection and uveitis was identified through a series of clinical and laboratory studies in the late 1980s-1990s. Since then, HTLV-1-related ocular manifestations such as keratoconjunctivitis sicca, interstitial keratitis, optic neuritis and adult T-cell leukemia/lymphoma (ATL)-related ocular manifestations have continuously been reported. During the three decades since the association between HTLV-1 and ocular pathologies was discovered, ophthalmic practice and research have advanced with the incorporation of new technologies into the field of ophthalmology. Accordingly, new findings from recent research have provided many insights into HTLV-1-associated ocular diseases. Advanced molecular technologies such as multiplex polymerase chain reaction (PCR)/broad-range PCR using ocular samples have enabled rapid and accurate diagnosis. Advanced ophthalmic technologies such as widefield fundus camera and optical coherence tomography (OCT) have clarified various features of HTLV-1-associated ocular manifestations, and identified characteristics such as the "knob-like ATL cell multiple ocular infiltration" (KAMOI) sign. Advanced drug delivery methods such as intravitreal injection and sub-Tenon injection have led to progress in preventing disease progression. This article describes global topics and the latest research findings for HTLV-1-associated ocular diseases, with reference to a large-scale nationwide survey of ophthalmologists. Current approaches and unmet needs for HTLV-1 infection in ophthalmology are also discussed.

Safety of Infliximab for the Eye Under Human T-Cell Leukemia Virus Type 1 Infectious Conditions in vitro

Use of biologics has been widely advocated for inflammatory diseases recently. Anti-tumor necrosis factor (TNF)-α antibody therapy is reportedly effective against ocular inflammation. However, side effects of TNF-α inhibition have been reported, particularly in the form of exacerbation of infections such as tuberculosis. Paradoxical reactions such as exacerbated inflammation are also well known. Around 20 million humans are infected with human T-cell leukemia virus type 1 (HTLV-1) globally, and this virus can cause adult T-cell leukemia, HTLV-1-associated myelopathy and HTLV-1 uveitis. As for ophthalmic concerns, it has not been identified whether anti-TNF-α antibody stimulates HTLV-1-infected cells and ocular cells to induce HTLV-1 uveitis in HTLV-1 carriers. Here we investigated the effects of anti-TNF-α antibody on ocular status under HTLV-1 infectious conditions using ocular cells and HTLV-1-infected cells in vitro. We used the ARPE-19 human retinal pigment epithelial cell line as ocular cells considered to play an important role in the blood-ocular barrier, and the MT2 HTLV-1-infected cell line. Jurkat cells were used as controls. Infliximab (IFX) was used as an anti-TNF-α antibody to achieve TNF-α inhibition. We evaluated the production of inflammatory cytokines and intercellular adhesion molecule (ICAM)-1, proliferation of ARPE-19, expression of TNF-α receptor (TNF-R) and HTLV-1 proviral DNA, and the percentage of apoptotic ARPE-19. Inflammatory cytokines such as interleukin (IL)-6, IL-8, TNF, and ICAM-1 were significantly elevated through contact between ARPE-19 and MT2. Treatment with IFX tented to inhibit TNF production, although the level of production was low, but changes in IL-6, IL-8, and ICAM-1 remained unaffected. Expression of TNFR was unaltered by IFX treatment. HTLV-1 proviral DNA was not significantly changed with treatment. No change in cell growth rate or apoptotic rate of ARPE-19 was seen with the addition of IFX. In conclusion, IFX did not exacerbate production of inflammatory cytokines, and did not affect expression of TNFR, proliferation of ARPE-19, HTLV-1 proviral load, or apoptosis of ARPE-19. These results suggest that IFX does not exacerbate HTLV-1-related inflammation in the eye and represents an acceptable treatment option under HTLV-1 infectious conditions.

Emerging Viral Infections Causing Anterior Uveitis

PURPOSE

To review the systemic and ocular manifestations of specific emergent viral infectious diseases relevant to the ophthalmologist with particular emphasis on anterior uveitis Methods: Review of literature.

RESULTS

Arboviral diseases are among the most important emergent and resurgent human infections, occurring mostly in tropical and subtropical zones, but appearing in virtually all regions of the world as a result of climate change, travel, and globalization. Arboviral infections are transmitted to humans by the bite of hematophagous arthropods, mainly mosquitoes. Systemic disease may range from asymptomatic to life-threatening. A wide variety of ocular manifestations, including uveitis, has been reported in association with these emerging viral diseases. Numerous viruses other than arboviruses also have been recently recognized as a potential cause of uveitis.

CONCLUSIONS

Proper clinical diagnosis of any emerging infectious disease is based on epidemiological data, history, systemic symptoms and signs, and the pattern of ocular involvement. The diagnosis is usually confirmed by detection of virus-specific DNA or antivirus antibodies in serum.

Systemic diseases in patients with HTLV-1-associated uveitis

BACKGROUND

Human T-lymphotropic virus type 1 (HTLV-1) carriers may develop severe systemic diseases, such as adult T cell leukaemia (ATL) or HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). This study aims to investigate systemic diseases of HTLV-1 carriers who had developed HTLV-1-associated uveitis (HAU).

METHODS

We investigated the occurrence of systemic diseases in 200 patients with HAU by performing a retrospective investigation of their medical records and examining the results of a postal survey.

RESULTS

The mean age of HAU onset was 49 years, and the total person-years from HAU onset was 1627. There were two cases of ATL. Of these, one was diagnosed with smouldering ATL at the time of HAU onset and the other developed acute-type ATL 4 years after HAU onset. There were 26 cases of HAM/TSP; of these, HAM/TSP occurred first in 13 cases and HAU occurred first in 11 cases. The interval between the onset of HAM/TSP and HAU ranged from 6 months to 6 years, with no significant difference observed based on whether HAM/TSP or HAU occurred first. Hyperthyroidism was noted in 45 cases and preceded onset in all cases. HAU onset occurred after starting thiamazole treatment, and in two cases HAU recurred each time thiamazole treatment was restarted.

CONCLUSION

HTLV-1 carriers with HAU may develop HAM/TSP more frequently than general carriers. HTLV-1 carriers undergoing treatment for hyperthyroidism may be prone to developing HAU.

RETINAL MANIFESTATIONS IN ADULT T-CELL LEUKEMIA/LYMPHOMA RELATED TO INFECTION BY THE HUMAN T-CELL LYMPHOTROPIC VIRUS TYPE-1

PURPOSE

To describe the retinal manifestations in adult T-cell leukemia (ATL) related to an infection by the human T-cell lymphotropic virus type-1 (HTLV-1).

METHODS

Retrospective case series of patients with ATL with retinal findings.

RESULTS

A total of 175 patients were diagnosed with ATL in Martinique between 1983 and 2013. Three of them showed intraocular findings related to ATL. They were bilateral deep retinal infiltrates associated with intermediate uveitis. In two cases, the ATL diagnosis was known. In the third, fluorescein angiography was remarkable for deep retinal infiltrates although fundus examination was unremarkable. The ATL cells were found in the blood of this patient. Despite chemotherapy, infiltrates progressed from the retinal periphery to the posterior pole in two patients, thus reducing visual acuity to light perception. They were associated with vasculitis.

CONCLUSION

Retinal involvement in ATL is very rare. It can occur at any point during the natural course of the disease. Human T-cell lymphotropic virus type-1 carriers should benefit from a regular ophthalmic examination, and a fluorescein angiography must be performed in all patients with human T-cell lymphotropic virus type-1 with vitreous cells. The presence of deep retinal infiltrates must raise suspicion for ATL in a patient with human T-cell lymphotropic virus type-1.

Treatment of rheumatoid arthritis with biologics may exacerbate HTLV-1-associated conditions: A case report

RATIONALE

There are roughly 5 to 10 million persons infected with human T-lymphotropic virus type 1 (HTLV-1) worldwide, and the safety of treating this population with biologics remains poorly understood.

PATIENT CONCERNS AND DIAGNOSIS

An HTLV-1-infected 66-year-old female with HTLV-1 uveitis (HU) and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). Her HU had been in remission and her HAM/TSP symptoms had been managed effectively with oral steroids for years. However, she developed severe rheumatoid arthritis (RA) after failing to respond well to conventional anti-rheumatic agents.

INTERVENTIONS

She was administered two intravenous 8mg/kg doses of the biologic tocilizumab.

OUTCOMES

Subsequently, her RA symptoms resolved, but she suffered a recurrence of HU and exacerbation of HAM/TSP symptoms. When she was switched back to steroid-based treatment, HU and HAM symptoms both improved, but RA symptoms again worsened. Finally, an attempt to substitute the biologic abatacept and reduce the steroids failed when HAM/TSP symptoms again became aggravated.

LESSONS

To the best of our knowledge, this represents the first report worldwide of a biologic aggravating HTLV-1-associated conditions. This report suggests that caution is advised when using biologics to treat HTLV-1-infected patients, though further research is required to clarify the situation.

A new era of uveitis: impact of polymerase chain reaction in intraocular inflammatory diseases

Uveitis is a sight-threatening intraocular inflammatory disorder which may occur from both infectious and non-infectious or autoimmune causes. The frequency of infectious uveitis and autoimmune uveitis varies depending on countries and regions. According to a nationwide survey conducted by the Japanese Ocular Inflammation Society, infectious and non-infectious uveitis accounted for 16.4 and 50.1% of new patients, respectively while the remaining 33.5% of new uveitis cases were not classified or were idiopathic uveitis. Infectious uveitis is particularly important because it causes tissue damage to the eye and may result in blindness unless treated. However, it can be treated if the pathogenic microorganisms are identified promptly and accurately. Remarkable advancements in molecular and immunological technologies have been made in the last decade, and the diagnosis of infectious uveitis has been greatly improved by the application of molecular and immunological investigations, particularly polymerase chain reaction (PCR). PCR performed on a small amount of ocular samples provides a prompt, sensitive, and specific molecular diagnosis of pathogenic microorganisms in the eye. This technology has opened a new era in the diagnosis and treatment of uveitis, enabling physicians to establish new clinical entities of uveitis caused by infectious microorganisms, identify pathogens in the eyes of many patients with uveitis, and determine prompt diagnosis and appropriate therapy. Here we review the PCR process, new PCR tests specialized for ocular diseases, microorganisms detected by the PCR tests, diseases in the eye caused by these microorganisms, and the clinical characteristics, diagnosis, and therapy of uveitis.

[Panuveitis associated with papillary carcinoma of the thyroid]

Ocular involvement secondary to thyroid carcinomas is uncommon. Uveal metastasis may occur. More rarely, they can be responsible for paraneoplastic syndromes. We report the case of a 64-year-old woman who presented with a severe bilateral panuveitis with venous vasculitis associated with hyperthyroidism from a multinodular goiter, complicated by papillary carcinoma. Systemic steroid therapy was initiated; ocular symptoms resolved completely after total thyroidectomy. Other causes of panuveitis with venous vasculitis were ruled out. This is the first reported case of panuveitis associated with papillary thyroid carcinoma. The occurrence of the ocular symptoms with hyperthyroidism and their remission after surgery supports the possibility that this association may not be coincidental. A paraneoplastic phenomenon is suspected.

Immunological homeostasis of the eye

Uveitis is a sight-threatening disease caused by autoimmune or infection-related immune responses. Studies in experimental autoimmune uveitis and in human diseases imply that activated CD4(+) T cells, Th1 and Th17 cells, play an effector role in ocular inflammation. The eye has a unique regional immune system to protect vision-related cells and tissues from these effector T cells. The immunological balance between the pathogenic CD4(+) T cells and regional immune system in the eye contributes to the maintenance of ocular homeostasis and good vision. Current studies have demonstrated that ocular parenchymal cells at the inner surface of the blood-ocular barrier, i.e. corneal endothelial (CE) cells, iris pigment epithelial (PE) cells, ciliary body PE cells, and retinal PE cells, contribute to the regional immune system of the eye. Murine ocular resident cells directly suppress activation of bystander T cells and production of inflammatory cytokines. The ocular resident cells possess distinct properties of immunoregulation that are related to disparate anatomical location. CE cells and iris PE cells, which are located at the anterior segment of the eye and face the aqueous humor, suppress activation of T cells via cell-to-cell contact mechanisms, whereas retinal PE cells suppress the activation of T cells via soluble factors. In addition to direct immune suppression, the ocular resident cells have another unique immunosuppressive property, the induction of CD25(+)Foxp3(+) Treg cells that also suppress the activation of bystander T cells. Iris PE cells convert CD8(+) T cells into Treg cells, while retinal PE cells convert CD4(+) T cells greatly and CD8(+) T cells moderately into Treg cells. CE cells also convert both CD4(+) T cells and CD8(+) T cells into Treg cells. The immunomodulation by ocular resident cells is mediated by various soluble or membrane-bound molecules that include TGF-β TSP-1, B7-2 (CD86), CTLA-2α, PD-L1 (B7-H1), galectin 1, pigment epithelial-derived factor PEDF), GIRTL, and retinoic acid. Human retinal PE cells also possess similar immune properties to induce Treg cells. Although there are many issues to be answered, human Treg cells induced by ocular resident cells such as retinal PE cells and related immunosuppressive molecules can be applied as immune therapy for refractive autoimmune uveitis in humans in the future.

HTLV-1 uveitis

Human T cell lymphotropic virus type 1 (HTLV-1) is the first retrovirus described as a causative agent of human disease. Following adult T cell leukemia/lymphoma and HLTV-1-associated myelopathy/tropical spastic paraparesis, HTLV-1 uveitis (HU) has been established as a distinct clinical entity caused by HTLV-1 based on seroepidemiological, clinical, and virological studies. HU is one of the most common causes of uveitis in endemic areas of Japan and can be a problematic clinical entity all over the world. HU occurs with a sudden onset of floaters and foggy vision, and is classified as an intermediate uveitis. Analysis of infiltrating cells in eyes with HU revealed that the majority of infiltrating cells were CD3(+) T cells, but not malignant cells or leukemic cells based on their T cell receptor usage. HTLV-1 proviral DNA, HTLV-1 protein, and viral particles were detected from infiltrating cells in eyes with HU. HTLV-1-infected CD4(+) T cell clones established from infiltrating cells in eyes with HU produced large amounts of various inflammatory cytokines, such as IL-1, IL-6, IL-8, TNF-α, and interferon-γ. Taken together, HU is considered to be caused by inflammatory cytokines produced by HTLV-1-infected CD4(+) T cells that significantly accumulate in eyes; therefore, topical and/or oral corticosteroid treatment is effective to treat intraocular inflammation in patients with HU. Further investigation is needed to establish a specific treatment for HU.

The epidemiology of human retrovirus-associated illnesses

Human T-cell leukemia/lymphoma virus type 1 (HTLV-1) was the first oncogenic human retrovirus discovered in 1980. It is estimated that around 10-20 million people are infected with HTLV-1 worldwide. However, HTLV-1 is not a ubiquitous virus. Indeed, HTLV-1 is present throughout the world with clusters of high endemicity including mainly southern Japan, the Caribbean region, parts of South America and intertropical Africa, with foci in the Middle East and Australia. The origin of this puzzling geographical repartition is probably linked to a founder effect in certain human groups. In the high endemic areas, 0.5 to 50% of the people have antibodies against HTLV-1 antigens. HTLV-1 seroprevalence increases with age, especially in women. HTLV-1 has 3 modes of transmission: mother to child, mainly through prolonged breastfeeding (> 6 months); sexual, mainly but not exclusively occurring from male to female; and by blood products contaminated by infected lymphocytes. HTLV-1 is mainly the etiological agent of two very severe diseases: a malignant T CD4+ cell lymphoproliferation of very poor prognosis, named adult T-cell leukemia/lymphoma (ATLL), and a chronic neuro-myelopathy named tropical spastic paraparesis/HTLV-1-associated myelopathy (TSP/HAM). HTLV-1 is also associated with rare anterior uveitis, infective dermatitis and myositis in some high HTLV-1 endemic areas. The repartition of the different molecular subtypes or genotypes is mainly linked to the geographical origin of the infected persons but not to the associated pathology. HTLV-1 possesses a remarkable genetic stability probably linked to viral amplification via clonal expansion of infected cells rather than by reverse transcription. This stability can be used as a molecular tool to gain better insights into the origin, evolution and modes of dissemination of HTLV-1 and infected populations. HTLV-1 originated in humans through interspecies transmission from STLV-1, a very closely related retrovirus, highly endemic in several populations of apes and Old World monkeys.

Clinical manifestations in individuals with recent diagnosis of HTLV type I infection

BACKGROUND

Human T-lymphotropic virus type 1 (HTLV-1) is known to cause HTLV-associated myelopathy (HAM)/tropical spastic paraparesis and adult T cell leukemia. A growing body of evidence links HTLV-1 infection with an increasing spectrum of disease, including uveitis, periodontal disease, arthropathy, sicca syndrome, and neurologic deficits.

OBJECTIVES

Despite recent findings, the natural history of HTLV-1 infection remains poorly defined. This study was designed to better characterize initial clinical and neurological findings in individuals diagnosed with HTLV-1 infection.

STUDY DESIGN

We conducted a cross-sectional study of 71 individuals recently diagnosed with HTLV-1 and 71 uninfected age- and sex-matched blood donors in Salvador, Brazil. Subjects were administered a standardized questionnaire and underwent physical exam.

RESULTS

HTLV-1 infected subjects were significantly more likely than controls to report complaints of hand and foot numbness (OR=5.3; 95% CI: 1.8-15.3; p=0.002 and OR=4.0; 95% CI: 1.3-12; p=0.013 respectively), difficulty running (OR=4.0; 95% CI: 1.1-14.2; p=0.032), nocturia (OR=5.0; 95% CI: 1.1-22.8; p=0.038), arthralgia (OR=3.3; 95% CI: 1.4-7.7; p=0.006), and photophobia (OR=3.3; 95% CI: 1.4-7.7; p=0.006).

CONCLUSIONS

Neurologic, ocular and rheumatologic complaints may be the first manifestations of HTLV-1 infection. Therefore, all patients presenting with initial diagnosis should be rigorously screened for these symptoms.

Regional immunity of the eye

This article reviews molecular mechanism of intraocular inflammation in animal models and in humans, and the immunological defence system of the eye with particular attention to ocular pigment epithelium. In experimental autoimmune uveitis (EAU), T lymphocytes, particularly CD4(+) T lymphocytes, play a central role in its immunopathogenic mechanisms. In humans, activated CD4(+) T cells also play a central role in the immunopathogenic mechanisms. This notion is demonstrated in two human diseases: one is Vogt-Koyanagi-Harada disease, and the other is human T-cell leukemia virus type 1 (HTLV-1) uveitis. Activated CD4(+) T cells infiltrating the eye are harmful to vision-related cells and tissues in the eye and cause sight-threatening conditions. However, the eye has regional defence systems to protect itself from these harmful activated T cells. We focus on ocular pigment epithelium (PE) and demonstrate immunoregulatory activity of iris PE and retinal PE. Iris PE suppresses activated CD4(+) T cells by cell-to-cell contact with a crucial role played by B7-2 molecule on iris PE and CTLA4 on T cells. The actual immunosuppressive factor being membrane bound TGF-beta. In contrast, retinal PE suppresses activated CD4(+) T cells by soluble factors, such as soluble TGF-beta and thrombospondin 1. In addition to the direct T-cell suppression by ocular PE, ocular PE has the capacity to promote activated T cells to regulatory T cells and use them as a tool to amplify the immune down regulation in the eye. The molecular mechanisms of generation of T regulatory cells by iris PE and retinal PE is also discussed.

Intermediate uveitis

Intermediate uveitis (IU) is described as inflammation in the anterior vitreous, ciliary body and the peripheral retina. In the Standardization of Uveitis Nomenclature (SUN) working group's international workshop for reporting clinical data the consensus reached was that the term IU should be used for that subset of uveitis where the vitreous is the major site of the inflammation and if there is an associated infection (for example, Lyme disease) or systemic disease (for example, sarcoidosis). The diagnostic term pars planitis should be used only for that subset of IU where there is snow bank or snowball formation occurring in the absence of an associated infection or systemic disease (that is, “idiopathic”). This article discusses the clinical features, etiology, pathogenesis, investigations and treatment of IU.

Hypothetical HTLV-I induction by ionizing radiation

Some laboratories have reported HTLV-I genome integration in cancer patients diagnosed with neoplasms of cervix and uterus. Usually, cancer patients undergo radiotherapy besides chemotherapy and surgery. It is hypothesized that radiation exposure would induce HTLV-I genome generation/activation, nevertheless there is not any report on experimental procedures trying to demonstrate HTLV-I gene expression in cells exposed to ionizing radiation. Anyway, earlier experimental works by Lieberman and Kaplan in 1959 succeeded to isolate retroviral particles, the radiation leukemia virus (RadLV), from thymic lymphomas of X-ray-irradiated C57BL/Ka mice, assuming that RadLV activated in the host by ionizing radiation, is released and transported to the thymus, where lymphoblasts, generated during the postradiation recovery phase, constitute an optimal target cell population for both replication of and eventual transformation by virus. Recent studies claim that besides RadLV, another retrovirus (RadLV-0) also induced by ionizing radiation is expressed and would be responsible for transformed cells of bone marrow origin. Epidemiological studies coincidentally point out to high incidence of HTLV-I infection in geographic areas displaying significant levels of radioactivity contamination as in Central Africa, Japan Islands and Mururoa Atoll. In our research work, we detected HTLV-I antibodies and viral genome integration in cancer patients of cervix and uterus and health care workers, whose had been exposed to ionizing radiation during radiotherapeutic procedures. Recombinational events among endogenous retrovirus and other retrogenic elements in the host cell genome under the bombardment of ionizing radiation from different sources could have optimized the phenomena occurrence or even ignited them to happen, generating HTLV-I genome, related viral peptides and virions. Therefore, it is feasible that exposure to ionizing radiation during therapeutic procedures could generate HTLV-I genome or induce the virus to be expressed in cells of cancer patients submitted to radiotherapy as also in healthy subjects under the same conditions, in artificial or natural radiation environment.

Les uvéites virales

Viral eye diseases are common and associated with different well-known forms of uveitis. However, experimental models and clinical observations have led to an infectious, in particular a viral etiology in different autoimmune conditions. The use of molecular techniques is particularly informative, not only to characterize the previously well-known subgroup of presumed viral uveitis, but also to define the role of these agents or emerging viruses in atypical forms of autoimmune uveitis resistant to conventional therapy. PCR detection of viral DNA in patients with uveitis is a rapid, sensitive and accurate procedure. Therefore, aqueous humor could be analyzed when uveitis is unresponsive to anti-inflammatory molecules, in order to exclude a viral condition and dramatically modify the therapeutic management. Several new viral entities have recently been identified such as cytomegalovirus-associated chronic anterior uveitis and non-necrotizing herpetic retinopathies in immunocompetent hosts. Systemic antiviral drugs should be proposed rapidly in order to control viral replication before the use of corticosteroids. Maintenance therapy based on low-dose antivirals can reduce the rate of recurrence and should be considered.

Prevalence of human T-cell leukemia virus types I and II in Switzerland

The retroviruses human immunodeficiency virus (HIV)-1/2 and human T-cell leukemia virus (HTLV)-I/II share modes of transmission, suggesting that efforts to monitor the current HIV-1 epidemic in Switzerland should be complemented by assessment of HTLV-I/II prevalence. This study presents an updated evaluation of HTLV-I/II infection among groups within the Swiss population polarized towards either low or increased risk of infection. Archived serum and peripheral blood mononuclear cell (PBMC) samples were examined for evidence of HTLV-I/II infection by enzyme-linked immunosorbant assay (ELISA), type-specific Western blot, type-specific polymerase chain reaction (PCR), DNA sequence analysis, and virus culture. Among blood donations obtained from low-risk Swiss donors, we report a complete lack of HTLV-II infection and the occurrence of HTLV-I infection limited to a prevalence of 0.079 per 100,000 (1/1,266,466). Among high-risk HIV-positive persons and HIV-negative persons at increased risk of HIV-infection, we report a focus of HTLV-I and HTLV-II infection at prevalence rates of 62 per 100,000 (1/1,620) and 309 per 100,000 (5/1,620), respectively. The finding of low HTLV-I/II prevalence among Swiss blood donors and containment of HTLV-I/II infection within known risk-groups does not support initiation of HTLV-I/II screening for Swiss blood, tissue, and organ donations.

Ocular manifestations of human T-cell lymphotropic virus type 1 infection

PURPOSE OF REVIEW

Human T-cell lymphotropic virus type 1 (HTLV-1) infection is endemic in Japan, the Caribbean islands, and parts of Central Africa and South America. Known ophthalmic manifestations of HTLV-1 include malignant infiltrates in patients with adult T-cell leukemia/lymphoma, retinal degeneration, neuroophthalmic disorders, and keratoconjunctivitis sicca in patients with HTLV-1-associated myelopathy/tropical spastic paraparesis, and HTLV-1-associated uveitis. This report reviews the recent developments and ocular findings reported in patients with HTLV-1-related diseases.

RECENT FINDINGS

Most of the knowledge of the ocular manifestations of HTLV-1 comes from southwestern Japan, which has the highest incidence of infection worldwide. During the past few years, however, ocular disease associated with HTLV-1 has been described in patients from other endemic areas genetically distinct and geographically distant from Japan. The most interesting of these was the recognition of corneal pathology in Brazilian and Caribbean patients with HTLV-1 that have not been described in Japanese patients. Other developments include the use of molecular techniques in the diagnostic evaluation of ocular tissues from HTLV-1 patients, and clinical studies demonstrating choroidal involvement by indocyanine green angiography in patients with HTLV-1-associated uveitis, and suggesting that retinal vasculitis unresponsive to corticosteroid therapy maybe a poor prognostic sign.

SUMMARY

The spectrum of ocular disease related to HTLV-1 continues to expand. Routine evaluation of HTLV-1-infected patients is important because immune-mediated or neoplastic ocular involvement may occur during the disease course. Genetic and environmental factors may play a role in the ocular manifestations of HTLV-1 in different populations.