HTLV-1-associated infective dermatitis: updates on the pathogenesis

High Ratio of Human T Cell Lymphotropic Virus Transmission and Prevalence of Human T Cell Lymphotropic Virus Type 1-Associated Diseases in Brazilian Family Groups Followed Up by the GIPH Cohort

A silent spread of human T cell lymphotropic virus type 1 (HTLV-1) has been occurring for thousands of years, with a high prevalence in some regions due to the sexual and vertical transmission and formation of family clusters. The time from HTLV-1 infection until the onset of virus-associated diseases is extremely long, approximately one to three decades. In this study, we evaluated intrafamilial HTLV-1 transmission and associated diseases in 1,204 individuals enrolled and followed up by the GIPH cohort between 1997 and 2017. The family groups (n = 43) were composed of 279 individuals who were tested for HTLV-1/human T cell lymphotropic virus type 2 (HTLV-2) and were classified as two groups according to the index case: blood donor (blood donors referred to the GIPH cohort) and nondonor (individuals referred to the GIPH cohort by other health services). The observed rates of HTLV-1 transmission and associated diseases among the relatives were high. Of 236 family members and sexual partners tested for HTLV, 104 (44.1%) were confirmed as having HTLV infection, with 36.7% of relatives whose index case was blood donors and 56.9% of relatives with nondonor index cases. At least one case of HTLV-1-associated myelopathy was observed in 42.9% of the families with intrafamilial transmission of HTLV-1. Brazil is an endemic area for HTLV-1/2 and has implemented mandatory universal screening of blood donors for HTLV-1/2 since 1993. However, the lack of public health services offer diagnosis for HTLV to the general population and pregnant women in the country makes it difficult to identify infected people, and contributes to the silent spread of the virus.

Non-cancerous complications in HTLV-1 carriers

INTRODUCTION

Human T-cell leukemia virus type 1 (HTLV-1) carriers may develop adult T-cell leukemia (ATL), or HTLV-1-associated myelopathy (HAM)/tropical spastic paraparesis (TSP). The evidence is limited regarding other diseases potentially associated with HTLV-1, such as HTLV-1-associated autoimmune diseases.

AREA COVERED

We summarized the available information on complications associated with HTLV-1 infection.

EXPERT OPINION

Previous studies showed that HTLV-1 carriers have an increased incidence of collagen diseases including Sjögren's syndrome, as well as dysthyroidism, diabetes mellitus, and atherosclerosis. Furthermore, cognitive deficits are observed in asymptomatic carriers and in symptomatic carriers who develop HAM/TSP. It is hypothesized that altered immunoregulation occurs as a result of persistent HTLV-1 infection. A systematic review and meta-analysis demonstrated that HTLV-1 infection itself has an adverse impact on overall survival. ATL alone cannot entirely explain the adverse impact of HTLV-1 infection on overall mortality, because the incidence is low, and therefore HTLV-1-associated diseases as a whole may contribute to the inferior clinical outcome. However, there are insufficient data to determine the causal relationship between HTLV-1 infection and each complication. While non-cancerous events linked to HTLV-1 infection are not fatal, they are likely to reduce quality of life. Large prospective studies should be conducted by international collaborators.

Comprehensive Insight into the Functional Roles of NK and NKT Cells in HTLV-1-Associated Diseases and Asymptomatic Carriers

Human T cell leukemia virus type 1 (HTLV-1) is the first human oncogenic retrovirus to be discovered and causes two major diseases: a progressive neuro-inflammatory disease, termed HTLV-1 associated myelopathy/tropical spastic paraparesis (HAM/TSP), and an aggressive malignancy of T lymphocytes known as adult T cell leukemia (ATL). Innate and acquired immune responses play pivotal roles in controlling the status of HTLV-1-infected cells and such, the outcome of HTLV-1 infection. Natural killer cells (NKCs) are the effector cells of the innate immune system and are involved in controlling viral infections and several types of cancers. The ability of NKCs to trigger cytotoxicity to provide surveillance against viruses and cancer depends on the balance between the inhibitory and activating signals. In this review, we will discuss NKC function and the alterations in the frequency of these cells in HTLV-1 infection.

Molecular mechanisms of action of negative pressure wound therapy: a systematic review

Negative pressure wound therapy (NPWT) has significantly advanced wound care and continues to find new applications. Its effects at a molecular level however, remain a subject of debate. The aim of this systematic review is to summarize the current evidence regarding the molecular mechanisms of action of NPWT. Medline, Embase, EBSCO databases and clinical trial registries were searched from inception to January 2023. Clinical studies, animal models or in-vitro studies that quantitatively or semi-quantitatively evaluated the influence of NPWT on growth factors, cytokine or gene-expression in the circulation or wound-bed were included. Risk of Bias assessment was performed using the RoBANS tool for non-randomized studies, the COCHRANE's Risk of Bias 2(ROB-2) tool for randomized clinical studies, OHAT tool for in-vitro studies or the SYRCLE tool for animal model studies. A descriptive summary was collated and the aggregated data is presented as a narrative synthesis. This review included 19 clinical studies, 11 animal studies and 3 in-vitro studies. The effects of NPWT on 43 biomarkers and 17 gene expressions were studied across included studies. NPWT stimulates modulation of numerous local and circulating cytokines and growth factor expressions to promote an anti-inflammatory profile. This is most likely achieved by downregulation of TNFα, upregulation of VEGF, TGF-β and fibronectin.

HAM/TSP Pathogenesis: The Transmigration Activity of HTLV-1-Infected T Cells into Tissues

Slowly progressive spastic paraparesis with bladder dysfunction, the main clinical feature of human T-cell leukemia virus-1 (HTLV-1)-associated myelopathy/tropical spastic paraparesis (HAM/TSP), is induced by chronic inflammation in the spinal cord, mainly the lower thoracic cord. A long-standing bystander mechanism, such as the destruction of surrounding tissues by inflammatory cytokines, etc., induced under the interaction between infiltrated HTLV-1-infected CD4⁺ T cells and HTLV-1-specific CD8⁺ cytotoxic T cells, has been considered implicated for the induction of chronic inflammation. As this bystander mechanism is triggered conceivably by the transmigration of HTLV-1-infected CD4⁺ T cells to the spinal cord, heightened transmigrating activity of HTLV-1-infected CD4⁺ T cells to the spinal cord might play a crucial role as the first responder in the development of HAM/TSP. This review evaluated the functions of HTLV-1-infected CD4⁺ T cells in HAM/TSP patients as the prerequisite for the acquisition of the activity such as adhesion molecule expression changes, small GTPases activation, and expression of mediators involved in basement membrane disruption. The findings suggest that HTLV-1-infected CD4⁺ T cells in HAM/TSP patients have enough potential to facilitate transmigration into the tissues. Future HAM/TSP research should clarify the molecular mechanisms leading to the establishment of HTLV-1-infected CD4⁺ T cells as the first responder in HAM/TSP patients. In addition, a regimen with an inhibitory activity against the transmigration of HTLV-1-infected CD4⁺ T cells into the spinal cord might be recommended as one of the therapeutic strategies against HAM/TSP patients.

Eosinophilia and elevated IgE serum levels: a red flag: when your diagnosis is not a common atopic eczema or common allergy

OBJECTIVE AND DESIGN

The hallmark of type 2 inflammation is eosinophilia and/or high IgE serum levels, mostly in atopic dermatitis. Nevertheless, many dermatoses may present similar findings. Our aim is to explore the biological and clinical spectrum of cutaneous manifestations involving tissue and/or systemic eosinophilia, and distinct serum levels of IgE, where atopic dermatitis or other primary allergic eczema, not always is the definitive diagnosis.

MATERIALS/METHODS

A total of 37 scientific papers were enrolled in this narrative review.

RESULTS

A diagnostic approach for patients with elevated serum IgE level and a list of conditions not related to atopic dermatitis that runs through inborn errors of immunity, inflammatory disorders, lung disorders, malignancy, infections/infestations are displayed. Regarding to peripheral eosinophilia, differential diagnosis is also explored and clinical patterns of skin diseases associated with tissue eosinophilia are listed, to facilitate our diagnosis.

CONCLUSIONS

We should maintain a high level of suspicion about other differential diagnosis involving eosinophilia and IgE dysregulation, especially in patients very young (when innate errors of the immunity may present) and in middle to elderly patients classified as having atopic dermatitis, due to the possibility of cutaneous hematological malignancies, paraneoplasia or autoimmune blistering diseases.

Transcriptional regulators of human oncoviruses: structural and functional implications for anticancer therapy

Transcription is often the first biosynthetic event of viral infection. Viruses produce preferentially viral transcriptional regulators (vTRs) essential for expressing viral genes and regulating essential host cell proteins to enable viral genome replication. As vTRs are unique viral proteins that promote the transcription of viral nucleic acid, vTRs interact with host proteins to suppress detection and immune reactions to viral infection. Thus, vTRs are promising therapeutic targets that are sequentially and structurally distinct from host cell proteins. Here, we review vTRs of three human oncoviruses: HBx of hepatitis B virus, HBZ of human T-lymphotropic virus type 1, and Rta of Epstein–Barr virus. We present three cunningly exciting and dangerous transcription strategies that make viral infections so efficient. We use available structural and functional knowledge to critically examine the potential of vTRs as new antiviral-anticancer therapy targets. For each oncovirus, we describe (i) the strategy of viral genome transcription; (ii) vTRs’ structure and binding partners essential for transcription regulation; and (iii) advantages and challenges of vTR targeting in antiviral therapies. We discuss the implications of vTR regulation for oncogenesis and perspectives on developing novel antiviral and anticancer strategies.

Case Report: Relevance of an Accurate Diagnosis and Monitoring of Infective Dermatitis Associated With Human T-Lymphotropic Virus Type 1 in Childhood

Human T-lymphotropic virus type 1 (HTLV-1) is a neglected retrovirus distributed worldwide and the ethiological agent of several pathologies, such as adult T-cell leukemia/lymphoma (ATLL), a chronic myelopathy known as HTLV-1 associated myelopathy/tropical spastic paraparesis (HAM/TSP) and infective dermatitis associated with HTLV-1 (IDH). HTLV-1 presents tropism for CD4⁺ T cells and induces deregulation of the cytokine profile. IDH is a severe, chronic superinfected eczema generally associated with Staphylococcus aureus and/or Streptococcus beta haemolyticus infection that responds partially to antibiotic therapy but prompt recurrence develops upon treatment withdrawal. IDH could be a risk factor for progression toward both HAM/TSP and ATLL and, similarly to other diseases associated with HTLV-1, it is sub-diagnosed particularly in non-endemic areas. Here, we present a case of IDH in a young boy living in Buenos Aires with symptoms since 2010, at the age of 5. HTLV-1 infection was suspected and confirmed in 2016. The patient exhibited chronic dermatosis with exudative eruption involving mainly the scalp, retroauricular regions, neck and abdomen. Clinical evaluations, routine laboratory tests, full blood count, and HTLV-1 diagnosis for this case are included.

Proteomics changes after negative pressure wound therapy in diabetic foot ulcers

Label-free quantitative mass spectrometry was used to analyze the differences in the granulation tissue protein expression profiles of patients with diabetic foot ulcers (DFUs) before and after negative-pressure wound therapy (NPWT) to understand how NPWT promotes the healing of diabetic foot wounds. A total of three patients with DFUs hospitalized for Wagner grade 3 were enrolled. The patients received NPWT for one week. The granulation tissue samples of the patients prior to and following NPWT for one week were collected. The protein expression profiles were analyzed with label-free quantitative mass spectrometry and the differentially expressed proteins (DEPs) in the DFU patients prior to and following NPWT for one week were identified. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses were conducted to annotate the DEPs and DEP-associated signaling pathways. Western blotting and ELISA were performed to validate the results. By comparing the differences in the protein profiles of granulation tissue samples prior to and following NPWT for one week, 36 proteins with significant differences were identified (P<0.05); 33 of these proteins were upregulated and three proteins were downregulated. NPWT altered proteins mainly associated with antioxidation and detoxification, the cytoskeleton, regulation of the inflammatory response, complement and coagulation cascades and lipid metabolism. The functional validation of the DEPs demonstrated that the levels of cathepsin S in peripheral blood and granulation tissue were significantly lower than those prior to NPWT (P<0.05), while the levels of protein S isoform 1, inter α-trypsin inhibitor heavy chain H4 and peroxiredoxin-2 in peripheral blood and granulation tissue were significantly higher than those prior to NPWT (P<0.05). The present study identified multiple novel proteins altered by NPWT and laid a foundation for further studies investigating the mechanism of action of NPWT.

Extracellular Vesicles in HTLV-1 Communication: The Story of an Invisible Messenger

Human T-cell lymphotropic virus type 1 (HTLV-1) infects 5-10 million people worldwide and is the causative agent of adult T-cell leukemia/lymphoma (ATLL) and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) as well as other inflammatory diseases. A major concern is that the most majority of individuals with HTLV-1 are asymptomatic carriers and that there is limited global attention by health care officials, setting up potential conditions for increased viral spread. HTLV-1 transmission occurs primarily through sexual intercourse, blood transfusion, intravenous drug usage, and breast feeding. Currently, there is no cure for HTLV-1 infection and only limited treatment options exist, such as class I interferons (IFN) and Zidovudine (AZT), with poor prognosis. Recently, small membrane-bound structures, known as extracellular vesicles (EVs), have received increased attention due to their potential to carry viral cargo (RNA and proteins) in multiple pathogenic infections (i.e., human immunodeficiency virus type I (HIV-1), Zika virus, and HTLV-1). In the case of HTLV-1, EVs isolated from the peripheral blood and cerebral spinal fluid (CSF) of HAM/TSP patients contained the viral transactivator protein Tax. Additionally, EVs derived from HTLV-1-infected cells (HTLV-1 EVs) promote functional effects such as cell aggregation which enhance viral spread. In this review, we present current knowledge surrounding EVs and their potential role as immune-modulating agents in cancer and other infectious diseases such as HTLV-1 and HIV-1. We discuss various features of EVs that make them prime targets for possible vehicles of future diagnostics and therapies.

Case Report: An Uncommon Clinical Case of Fatal Adult T-Cell Leukemia/Lymphoma Associated with HTLV-1 and Suspected due to Cutaneous Lesions and Epidemiologic Data

Adult T-cell leukemia/lymphoma (ATLL) is a peripheral T-cell neoplasm caused by the human T-cell leukemia virus type 1 (HTLV-1). It is characterized by a short survival time and lack of response to chemotherapy. We report a case of a 56-year-old woman, from the Brazilian northeast state of Bahia, who presented with a 2-month history of infiltrated papular and nodular skin lesions, especially on her forehead and also on her lower and upper limbs. Laboratory tests revealed positive serology for HTLV-1. Histopathological findings and the immunohistochemical profile confirmed the diagnosis of adult T-cell lymphoma/leukemia. A month after the diagnosis, the patient presented acute fatigue and pronounced paleness of the skin, dying of septic shock after her first chemotherapy cycle. The aim of this case report was to emphasize the importance of maintaining high clinical suspicion for ATLL, considering the epidemiological profile of the disease, especially for patients whose only early symptoms are cutaneous lesions.

Infective dermatitis: A purely cutaneous manifestation of HTLV-1 infection

Infectious dermatitis is a cutaneous manifestation of HTLV-1 infection. Although initially described in children in Jamaica, it is well documented that the disease can also present in adults. The clinical picture is of an oozing dermatitis affecting the scalp, face, retroauricular areas, the neck, and intertrigious areas, such as the axilla and groin. Histologically it has two patterns: a superficial perivascular dermatitis or a lichenoid dermatitis. The epidermal hyperplasia may mimic psoriasis. An important differential diagnosis is with mycosis fungoides, with epidermotropism, alignment of lymphocytes along the epidermal junction, lymphocytes in halo and wiry bundles of collagen in the papillary dermis. An important difference is the lack of marked lymphocytic atypia. The infiltrate is composed of a predominance of CD8-positive lymphocytes, analogous to what is seen in tropical spastic paraparesis. Infectious dermatitis patients may be confused with many common dermatological conditions, such a atopic dermatitis and contact dermatitis. Its diagnosis represent a challenge both to clinicians and dermatopathologists working in endemic areas.

Human oncoviruses: Mucocutaneous manifestations, pathogenesis, therapeutics, and prevention: Hepatitis viruses, human T-cell leukemia viruses, herpesviruses, and Epstein-Barr virus

In 1964, the first human oncovirus, Epstein-Barr virus, was identified in Burkitt lymphoma cells. Since then, 6 other human oncoviruses have been identified: human papillomavirus, Merkel cell polyomavirus, hepatitis B and C viruses, human T-cell lymphotropic virus-1, and human herpesvirus-8. These viruses are causally linked to 12% of all cancers, many of which have mucocutaneous manifestations. In addition, oncoviruses are associated with multiple benign mucocutaneous diseases. Research regarding the pathogenic mechanisms of oncoviruses and virus-specific treatment and prevention is rapidly evolving. Preventative vaccines for human papillomavirus and hepatitis B virus are already available. This review discusses the mucocutaneous manifestations, pathogenesis, diagnosis, treatment, and prevention of oncovirus-related diseases. The first article in this continuing medical education series focuses on diseases associated with human papillomavirus and Merkel cell polyomavirus, while the second article in the series focuses on diseases associated with hepatitis B and C viruses, human T-cell lymphotropic virus-1, human herpesvirus-8, and Epstein-Barr virus.

Dendritic Cells Promote the Spread of Human T-Cell Leukemia Virus Type 1 via Bidirectional Interactions with CD4+ T Cells

Human T-cell leukemia virus type 1 (HTLV-1) propagates within and between individuals via cell-to-cell transmission, and primary infection typically occurs across juxtaposed mucosal surfaces during breastfeeding or sexual intercourse. It is therefore likely that dendritic cells (DCs) are among the first potential targets for HTLV-1. However, it remains unclear how DCs contribute to virus transmission and dissemination in the early stages of infection. We show that an HTLV-1-infected cell line (MT-2) and naturally infected CD4⁺ T cells transfer p19⁺ viral particles to the surface of allogeneic DCs via cell-to-cell contacts. Similarly organized cell-to-cell contacts also facilitate DC-mediated transfer of HTLV-1 to autologous CD4⁺ T cells. These findings shed light on the cellular structures involved in anterograde and retrograde transmission and suggest a key role for DCs in the natural history and pathogenesis of HTLV-1 infection.

Human T-cell leukemia virus-associated malignancy

Human T-cell leukemia virus type 1 (HTLV-1) is a tumorigenic delta retrovirus and the causative infectious agent of a non-Hodgkin's peripheral T-cell malignancy called adult T-cell leukemia/lymphoma (ATL). ATL develops in approximately 5% of infected individuals after a significant clinical latency period of several decades. Clinical classifications of ATL include smoldering, chronic, lymphoma, and acute subtypes, with varying median survival ranges of a few months to several years. Depending on the ATL subtype and disease symptoms, treatment options include 'watchful waiting', chemotherapy, antiviral therapy, allogeneic hematopoietic stem cell transplantation (alloHSCT), and targeted therapies. Herein we review the characteristics and development of ATL, as well as current and future treatment options and perspectives.

Immunoactivation induced by chronic viral infection inhibits viral replication and drives immunosuppression through sustained IFN-I responses

Acute or chronic viral infections can lead to generalized immunosuppression. Several mechanisms, such as immunopathology of CD8⁺ T cells, inhibitory receptors, or regulatory T (Treg) cells, contribute to immune dysfunction. Moreover, patients with chronic viral infections usually do not respond to vaccination, a finding that has not been previously explained. Recently, we reported that CD169⁺ macrophages enforce viral replication, which is essential for guaranteeing antigen synthesis and efficient adaptive immune responses. In the present study, we used a chronic lymphocytic choriomeningitis virus infection mouse model to determine whether this mechanism is affected by chronic viral infection, which may impair the activation of adaptive immunity. We found that enforced viral replication of a superinfecting virus is completely blunted in chronically infected mice. This absence of enforced viral replication in CD169⁺ macrophages is not explained by CD8⁺ T‐cell‐mediated immunopathology but rather by prolonged IFN‐I responses. Consequently, the absence of viral replication impairs both antigen production and the adaptive immune response against the superinfecting virus. These findings indicate that chronic infection leads to sustained IFN‐I action, which is responsible for the absence of an antiviral immune response against a secondary viral infection.

Privileged Structures Meet Human T-Cell Leukemia Virus-1 (HTLV-1): C2-Symmetric 3,4-Disubstituted Pyrrolidines as Nonpeptidic HTLV-1 Protease Inhibitors

3,4-disubstituted pyrrolidines originally designed to inhibit the closely related HIV-1 protease were evaluated as privileged structures against HTLV-1 protease (HTLV-1 PR). The most potent inhibitor of this series exhibits two-digit nanomolar affinity and represents, to the best of our knowledge, the most potent nonpeptidic inhibitor of HTLV-1 PR described so far. The X-ray structures of two representatives bound to HTLV-1 PR were determined, and the structural basis of their affinity is discussed.

Recurrent Facial Erythema with Cytotoxic T Cell Infiltration as a Possible Reactive Eruption in a Human T-Cell Lymphotropic Virus Type 1 Carrier

Human T-cell lymphotropic virus type 1 (HTLV-1) induces adult T cell leukemia/lymphoma (ATLL), HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) and carrier. Approximately half of ATLL patients have direct skin involvement of neoplastic cells. However, there exist HTLV-1-associated reactive eruptions with a predominant infiltrate of non-neoplastic CD8+ T cells in ATLL, HAM/TSP and carrier. A 50-year-old Japanese female HTLV-1 carrier had several episodes of itchy, indurated erythema that occurred diffusely on the face and neck, lasted for 2 weeks and spontaneously subsided without sequelae. Histopathologically, CD3+ T cells infiltrated the upper dermis, and part of the infiltrating cells were CD4+CD25+, sharing the phenotype with ATLL neoplastic cells. An aggregate of CD8+ T cells bearing the cytotoxic molecule TIA-1 was also present. It is possible that skin-affinitive HTLV-1+CD4+ T cells propagated and subsequently disappeared as a result of cytotoxic T cell attack.

Characterizing the protonation states of the catalytic residues in apo and substrate-bound human T-cell leukemia virus type 1 protease

Human T-cell leukemia virus type 1 (HTLV-1) protease is an attractive target when developing inhibitors to treat HTLV-1 associated diseases. To study the catalytic mechanism and design novel HTLV-1 protease inhibitors, the protonation states of the two catalytic aspartic acid residues must be determined. Free energy simulations have been conducted to study the proton transfer reaction between the catalytic residues of HTLV-1 protease using a combined quantum mechanical and molecular mechanical (QM/MM) molecular dynamics simulation. The free energy profiles for the reaction in the apo-enzyme and in an enzyme - substrate complex have been obtained. In the apo-enzyme, the two catalytic residues are chemically equivalent and are expected to be both unprotonated. Upon substrate binding, the catalytic residues of HTLV-1 protease evolve to a singly protonated state, in which the OD1 of Asp32 is protonated and forms a hydrogen bond with the OD1 of Asp32', which is unprotonated. The HTLV-1 protease-substrate complex structure obtained from this simulation can serve as the Michaelis complex structure for further mechanistic studies of HTLV-1 protease while providing a receptor structure with the correct protonation states for the active site residues toward the design of novel HTLV-1 protease inhibitors through virtual screening.

Skin manifestations of adult T-cell leukemia/lymphoma: clinical, cytological and immunological features

Adult T-cell leukemia/lymphoma (ATLL) is a malignancy of mature T cells caused by human T-cell leukemia virus type I. The endemic areas include Japan, especially in Kyushu, the Caribbean, Papua New Guinea, South America and Africa. Approximately 50% of ATLL patients exhibit skin manifestations. Cytologically, ATLL tumor cells are characterized by CD4(+) CD25(+) regulatory T-cell phenotype, high expressions of CCR4, and programmed cell death (PD)-1 and PD-ligand 1. The skin eruptions are categorized into six types: patch, plaque, multipapular, nodulotumoral, erythrodermic and purpuric. The overall survival of the eruption-bearing patients was poorer than that of the non-eruption-bearing patients in acute, chronic and smoldering types, but the survival levels of both groups were comparable in lymphoma type. The prognosis was poor in the order of: erythrodermic, nodulotumoral, multipapular/purpuric, plaque, then patch. Multivariate analysis revealed that the eruption type is an independent prognostic factor for ATLL. Patients may have other skin manifestations, secondary and infective lesions.

[Recurrent facial palsy revealing Human T-lymphotropic virus type 1 (HTLV-1) infection]

INTRODUCTION

Neurological involvement of Human T-lymphotropic virus type 1 (HTLV-1) mainly results in myelopathy (tropical spastic paraparesis). However, cranial nerve impairment, including facial nerve damage, is rare in patients with HTLV-1 infection.

OBSERVATION

We report the case of a patient, originally from Caribbean islands, who developed recurrent bilateral facial palsy (six recurrences during the 7-year follow-up). Both blood and cerebrospinal fluid serologies were positive for HTLV-1. The diagnosis of recurring bilateral facial palsy revealing HTLV-1 infection was made.

CONCLUSION

Our case report underscores that HTLV-1 infection should be considered in patients, coming from endemic areas (Caribbean islands, South America, Japan and Africa), who exhibit recurrent bilateral facial palsy. Our data therefore indicate that HTLV-1 serology should be routinely performed in these patients.

Expansion of natural killer cells in peripheral blood in a Japanese elderly with human T-cell lymphotropic virus type 1-related skin lesions

Natural killer (NK) cells were proposed to play an important role in the pathogenesis of human T-cell lymphotropic virus type 1- (HTLV-1-) associated neurologic disease. Our patient was a 77-year-old Japanese man, who had been treated for infective dermatitis associated with HTLV-1 for nearly 10 years. When referred to us, he had facial eczema/edema as well as extensive dermatitis at the neck/upper chest and nuchal area/upper back regions. Dermal lesions had CD3+CD4+ cells, but no NK cells. Flow cytometry of his peripheral blood showed a phenotype of CD2+ (97%), CD3+ (17%), CD4+ (12%), CD7+ (94%), CD8+ (6%), CD11c+ (70%), CD16+ (82%), CD19+ (0%), CD20+ (0%), CD56+ (67%), HLA-DR+ (68%), and NKp46+ (36%). Absolute numbers of CD56+NK cells in the peripheral blood were in a range of 986/μL–1,270/μL. The expanded NK cells in the peripheral blood are considered to be reactive, to maintain the confinement of the HTLV-1-positive CD4+ cells in the skin, and to prevent the progression of the disease.

DC-T cell virological synapses and the skin: novel perspectives in dermatology

Virological synapses (VS) increase cell-to-cell viral transmission and facilitate propagation of human immunodeficiency virus type 1 (HIV-1) and human T-cell leukaemia virus type 1 (HTLV-1). VS formation also plays a more general role in viral replication and dissemination. VS have been observed in vitro and ex vivo between uninfected T cells and T cells infected with HIV-1 or HTLV-1. In addition, dendritic cells (DC) infected with HIV-1 also play an important role in viral transmission to uninfected CD4+ T cells via VS formation. Recent studies revealed that several DC subsets are also infected with HTLV-1. These findings may help explain the rapid dissemination of both viruses within secondary lymphoid tissues in vivo. VS also explain, at least in part, why HIV-1 can propagate in the mucosal sites during sexual transmission. Furthermore, in the case of HTLV-1, VS can potentially explain some of the features of HTLV-1-associated dermatitis as infected T cells in the skin contribute to the pathogenesis of this condition.

A case of post-transplant adult T-cell leukemia/lymphoma presenting myelopathy similar to but distinct from human T-cell leukemia virus type I (HTLV- I)-associated myelopathy

INTRODUCTION

Adult T-cell leukemia/lymphoma (ATL) responds poorly to conventional chemotherapy, but allogeneic stem cell transplantation (allo-SCT) may improve disease prognosis. Herein, we report a female patient with human T-cell leukemia virus type I (HTLV-I)-associated myelopathy (HAM)-like myelopathy following allo-SCT for ATL.

CASE REPORT

She developed crural paresis 14 months after allo-SCT. Initially, she was diagnosed with central nervous system (CNS) relapse of ATL and treated with intrathecal injection and whole brain and spine irradiation. Her symptoms recurred 5 months later, when a cerebrospinal fluid (CSF) specimen showed increased CD4 + CXCR3 + CCR4+ cell numbers and levels of neopterin and CXCL10 (IP-10).

DISCUSSION

These results suggest the possible involvement of a certain immunological mechanism such as HAM in her symptoms, irrespective of the lack of anti-HTLV-I antibody in her CSF. Because a definitive diagnosis of CNS manifestation of ATL is sometimes difficult, multi-modal laboratory data are required for differential diagnosis.

Structural basis for HTLV-1 protease inhibition by the HIV-1 protease inhibitor indinavir

HTLV-1 protease (HTLV-1 PR) is an aspartic protease which represents a promising drug target for the discovery of novel anti-HTLV-1 drugs. The X-ray structure of HTLV-1 PR in complex with the well-known and approved HIV-1 PR inhibitor Indinavir was determined at 2.40 Å resolution. In this contribution, we describe the first crystal structure in complex with a nonpeptidic inhibitor that accounts for rationalizing the rather moderate affinity of Indinavir against HTLV-1 PR and provides the basis for further structure-guided optimization strategies.

High prevalence of skin disorders among HTLV-1 infected individuals independent of clinical status

Background

Human T-cell lymphotropic virus type 1 (HTLV-1) infection can increase the risk of developing skin disorders. This study evaluated the correlation between HTLV-1 proviral load and CD4⁺ and CD8⁺ T cells count among HTLV-1 infected individuals, with or without skin disorders (SD) associated with HTLV-1 infection [SD-HTLV-1: xerosis/ichthyosis, seborrheic dermatitis or infective dermatitis associated to HTLV-1 (IDH)].

Methods

A total of 193 HTLV-1-infected subjects underwent an interview, dermatological examination, initial HTLV-1 proviral load assay, CD4⁺ and CD8⁺ T cells count, and lymphproliferation assay (LPA).

Results

A total of 147 patients had an abnormal skin condition; 116 (79%) of them also had SD-HTLV-1 and 21% had other dermatological diagnoses. The most prevalent SD-HTLV-1 was xerosis/acquired ichthyosis (48%), followed by seborrheic dermatitis (28%). Patients with SD-HTLV-1 were older (51 vs. 47 years), had a higher prevalence of myelopathy/tropical spastic paraparesis (HAM/TSP) (75%), and had an increased first HTLV-1 proviral load and basal LPA compared with patients without SD-HTLV-1. When excluding HAM/TSP patients, the first HTLV-1 proviral load of SD-HTLV-1 individuals remains higher than no SD-HTLV-1 patients.

Conclusions

There was a high prevalence of skin disorders (76%) among HTLV-1-infected individuals, regardless of clinical status, and 60% of these diseases are considered skin disease associated with HTLV-1 infection.

HTLV-1 infection may increase the risk of developing skin disorders. A total of 193 HTLV-1 infected subjects were studied, including asymptomatic carriers and HAM/TSP patients. Of the subjects, 76% had an abnormal skin condition, with a high prevalence both among HTLV-1 asymptomatic carriers and HAM/TSP patients. The most prevalent SD-HTLV-1 was xerosis/acquired ichthyosis (48%), followed by seborrheic dermatitis (28%). Patients with SD-HTLV-1 were older (51 vs. 47 years), had a higher prevalence of myelopathy/tropical spastic paraparesis (HAM/TSP) (75%) and an increased first HTLV-1 proviral load compared with patients without SD-HTLV-1. When excluding HAM/TSP patients, the first HTLV-1 proviral load of SD-HTLV-1 individuals remains higher than no SD-HTLV-1 patients. Thus, skin diseases are highly prevalent among HTLV-1-infected individuals.