Current views in HTLV-I-associated adult T-cell leukemia/lymphoma

Stem cell therapy for HTLV-1 induced adult T-cell leukemia/lymphoma (ATLL): A comprehensive review

Adult T-cell leukemia/lymphoma (ATLL) is a rare and aggressive form of cancer associated with human T-cell lymphotropic virus type 1 (HTLV-1) infection. The emerging field of stem cell therapies for ATLL is discussed, highlighting the potential of hematopoietic stem cell transplantation (HSCT) and genetically modified stem cells. HSCT aims to eradicate malignant T-cells and restore a functional immune system through the infusion of healthy donor stem cells. Genetically modified stem cells show promise in enhancing their ability to target and eliminate ATLL cells. The article presents insights from preclinical studies and limited clinical trials, emphasizing the need for further research to establish the safety, efficacy, and long-term outcomes of stem cell therapies for ATLL and challenges associated with these innovative approaches are also explored. Overall, stem cell therapies hold significant potential in revolutionizing ATLL treatment, and ongoing clinical trials aim to determine their benefits in larger patient populations.

Human T-cell Lymphotropic Virus Type 1 (HTLV-1)-Associated Adult T-cell Leukemia/Lymphoma in a Patient Previously Treated for Strongyloidiasis

Adult T-cell leukemia/lymphoma (ATLL) is a rare form of T-cell lymphoma with poor median survival time and limited response to chemotherapy. We present a 45-year-old female from Ghana with generalized body rash, hypercalcemia, lymphadenopathy, and lytic bone lesions. She had a history of strongyloidiasis, treated two years ago, and her serology was positive for the human T-cell lymphotropic virus type 1 (HTLV-1). Histopathology of cervical lymph node and abdominal rash biopsy revealed T-cell lymphoma. We present a literature review on the topic and the challenges of diagnosis. We emphasize the importance of considering HTLV-1-associated ATLL in patients who have been treated for strongyloidiasis in the past and are presenting with rash or lymphadenopathy.

Catalytic Mechanism of Human T-Cell Leukemia Virus Type 1 Protease Investigated by Combined QM/MM Molecular Dynamics Simulations

Combined quantum mechanical and molecular mechanical (QM/MM) molecular dynamics simulations were performed to investigate the catalytic mechanism of human T-cell leukemia virus type 1 (HTLV-1) protease, a retroviral aspartic protease that is a potential therapeutic target for curing HTLV-1-associated diseases. To elucidate the proteolytic cleavage mechanism, we determined the two-dimensional free energy surfaces of the HTLV-1 protease-catalyzed reactions through various possible pathways. The free energy simulations suggest that the catalytic reactions of the HTLV-1 protease occur in the following sequential steps: (1) a proton is transferred from the lytic water to Asp32', followed by the nucleophilic addition of the resulting hydroxyl to the carbonyl carbon of the scissile bond, forming a tetrahedral oxyanion intermediate, and (2) a proton is transferred from Asp32 to the peptide nitrogen of the scissile bond, leading to the spontaneous breakage of the scissile bond. The rate-limiting step of this catalytic process is the proton transfer from Asp32 to the peptide nitrogen of the scissile bond, with a free energy of activation of 21.1 kcal/mol. This free energy barrier is close to the experimentally determined free energy of activation (16.3 kcal/mol) calculated from the measured catalytic rate constant (k_cat). This mechanistic study provides detailed dynamic and structural information that will facilitate the design of mechanism-based inhibitors for the treatment of HTLV-1-associated diseases.

Fucoxanthin: A Promising Phytochemical on Diverse Pharmacological Targets

Fucoxanthin (FX) is a special carotenoid having an allenic bond in its structure. FX is extracted from a variety of algae and edible seaweeds. It has been proved to contain numerous health benefits and preventive effects against diseases like diabetes, obesity, liver cirrhosis, malignant cancer, etc. Thus, FX can be used as a potent source of both pharmacological and nutritional ingredient to prevent infectious diseases. In this review, we gathered the information regarding the current findings on antimicrobial, antioxidant, anti-inflammatory, skin protective, anti-obesity, antidiabetic, hepatoprotective, and other properties of FX including its bioavailability and stability characteristics. This review aims to assist further biochemical studies in order to develop further pharmaceutical assets and nutritional products in combination with FX and its various metabolites.

Structural basis for cooperative regulation of KIX-mediated transcription pathways by the HTLV-1 HBZ activation domain

The human T cell leukemia virus I basic leucine zipper protein (HTLV-1 HBZ) maintains chronic viral infection and promotes leukemogenesis through poorly understood mechanisms involving interactions with the KIX domain of the transcriptional coactivator CBP and its paralog p300. The KIX domain binds regulatory proteins at the distinct MLL and c-Myb/pKID sites to form binary or ternary complexes. The intrinsically disordered N-terminal activation domain of HBZ (HBZ AD) deregulates cellular signaling pathways by competing directly with cellular and viral transcription factors for binding to the MLL site and by allosterically perturbing binding of the transactivation domain of the hematopoietic transcription factor c-Myb. Crystal structures of the ternary KIX:c-Myb:HBZ complex show that the HBZ AD recruits two KIX:c-Myb entities through tandem amphipathic motifs (L/V)(V/L)DGLL and folds into a long α-helix upon binding. Isothermal titration calorimetry reveals strong cooperativity in binding of the c-Myb activation domain to the KIX:HBZ complex and in binding of HBZ to the KIX:c-Myb complex. In addition, binding of KIX to the two HBZ (V/L)DGLL motifs is cooperative; the structures suggest that this cooperativity is achieved through propagation of the HBZ α-helix beyond the first binding motif. Our study suggests that the unique structural flexibility and the multiple interaction motifs of the intrinsically disordered HBZ AD are responsible for its potency in hijacking KIX-mediated transcription pathways. The KIX:c-Myb:HBZ complex provides an example of cooperative stabilization in a transcription factor:coactivator network and gives insights into potential mechanisms through which HBZ dysregulates hematopoietic transcriptional programs and promotes T cell proliferation.

Case Report: Orbital Tumor Revealing Adult T-Cell Leukemia/Lymphoma Associated with Human T-Cell Lymphotropic Virus Type-1

Adult T-cell Leukemia/Lymphoma (ATLL) is a sight- and life-threatening complication of human T-cell lymphotropic virus type 1 (HTLV-1) infection. Ophthalmic manifestations include uveitis, optic nerve oedema, retinal vasculitis, and lymphomatous infiltration. Orbital lesions are rare. We report the case of an orbital tumor revealing systemic ATLL in a 45-year-old Dominican patient who died despite treatment. Apart from late-grade cutaneous T-cell lymphoma, ATLL is the only T-lymphoma to develop in the orbit. Diagnosis is based on serologic evidence of HTLV-1 infection, cytology, and blood sample analysis. Biopsy is deemed necessary. Given the poor prognosis of ATLL and the worldwide presentation of HTLV-1, physicians should consider ATLL in the differential diagnosis of orbital malignant tumor and look for HTLV-1 infection in populations at risk.

Ancient cancers and infection-induced oncogenesis

Cancers have been reported in bone and soft tissue of ancient agricultural populations. Fossilized bones from prehistoric periods provide evidence of tumors but only one example of cancer. Difficulties in diagnosing the causes of lesions in mummified tissue and fossilized bone, and in interpreting the prevalence of cancers from remains, draw attention to the need for complementary approaches to assess the occurrence of cancer in ancient populations. This paper integrates current knowledge about pathogen induction of cancer with phylogenetic analyses of oncogenic pathogens, and concludes that pathogen-induced cancers were probably generally present in ancient historic and prehistoric human populations. Consideration of cancers in extant human populations and wildlife lends credence to this conclusion, with the caveat that the presence of cancers may depend on population-specific exposures to oncogenic parasites and carcinogens.

Clinical significance of microRNAs in chronic and acute human leukemia

Small non-coding microRNAs (miRNAs) are epigenetic regulators that target specific cellular mRNA to modulate gene expression patterns and cellular signaling pathways. miRNAs are involved in a wide range of biological processes and are frequently deregulated in human cancers. Numerous miRNAs promote tumorigenesis and cancer progression by enhancing tumor growth, angiogenesis, invasion and immune evasion, while others have tumor suppressive effects (Hayes, et al., Trends Mol Med 20(8): 460-9, 2014; Stahlhut and Slack, Genome Med 5 (12): 111, 2013). The expression profile of cancer miRNAs can be used to predict patient prognosis and clinical response to treatment (Bouchie, Nat Biotechnol 31(7): 577, 2013). The majority of miRNAs are intracellular localized, however circulating miRNAs have been detected in various body fluids and represent new biomarkers of solid and hematologic cancers (Fabris and Calin, Mol Oncol 10(3):503-8, 2016; Allegra, et al., Int J Oncol 41(6): 1897-912, 2012). This review describes the clinical relevance of miRNAs, lncRNAs and snoRNAs in the diagnosis, prognosis and treatment response in patients with chronic lymphocytic leukemia (CLL), chronic myeloid leukemia (CML), acute lymphocytic leukemia (ALL), acute myeloid leukemia (AML) and acute adult T-cell leukemia (ATL).

Infection and cancer in multicellular organisms

Evolutionary considerations suggest that oncogenic infections should be pervasive among animal species. Infection-associated cancers are well documented in humans and domestic animals, less commonly reported in undomesticated captive animals, and rarely documented in nature. In this paper, we review the literature associating infectious agents with cancer to evaluate the reasons for this pattern. Non-malignant infectious neoplasms occur pervasively in multicellular life, but oncogenic progression to malignancy is often uncertain. Evidence from humans and domestic animals shows that non-malignant infectious neoplasms can develop into cancer, although generally with low frequency. Malignant neoplasms could be difficult to find in nature because of a low frequency of oncogenic transformation, short survival after malignancy and reduced survival prior to malignancy. Moreover, the evaluation of malignancy can be ambiguous in nature, because criteria for malignancy may be difficult to apply consistently across species. The information available in the literature therefore does not allow for a definitive assessment of the pervasiveness of infectious cancers in nature, but the presence of infectious neoplasias and knowledge about the progression of benign neoplasias to cancer is consistent with a widespread but largely undetected occurrence.

Mutation of epigenetic regulators TET2 and MLL3 in patients with HTLV-I-induced acute adult T-cell leukemia

Background

Epigenetic regulators play a critical role in the maintenance of specific chromatin domains in an active or repressed state. Disruption of epigenetic regulatory mechanisms is widespread in cancer cells and largely contributes to the transformation process through active repression of tumor suppressor genes. While mutations of epigenetic regulators have been reported in various lymphoid malignancies and solid cancers, mutation of these genes in HTLV-I-associated T-cell leukemia has not been investigated.

Method

Here we used whole genome next generation sequencing (NGS) of uncultured freshly isolated ATL samples and identified the presence of mutations in SUZ12, DNMT1, DNMT3A, DNMT3B, TET1, TET2, IDH1, IDH2, MLL, MLL2, MLL3 and MLL4.

Results

TET2 was the most frequently mutated gene, occurring in 32 % (10/31) of ATL samples analyzed. Interestingly, NGS revealed nonsense mutations accompanied by loss of heterozygosity (LOH) in TET2 and MLL3, which was further confirmed by cloning and direct sequencing of DNA from uncultured cells. Finally, direct sequencing of matched control and tumor samples revealed that TET2 mutation was present only in ATL tumor cells.

Conclusions

Our results suggest that inactivation of MLL3 and TET2 may play an important role in the tumorigenesis process of HTLV-I-induced ATL.

Electronic supplementary material

The online version of this article (doi:10.1186/s12943-016-0500-z) contains supplementary material, which is available to authorized users.

HESI/FDA workshop on immunomodulators and cancer risk assessment: Building blocks for a weight-of-evidence approach

Profound immunosuppression (e.g., AIDS, transplant therapy) is epidemiologically associated with an increased cancer risk, and often with oncogenic viruses. It is currently unclear how broadly this association translates to therapeutics that modulate immunity. A workshop co-sponsored by the FDA and HESI examined how perturbing the immune system may contribute to carcinogenesis, and highlighted priorities for improving non-clinical risk assessment of targeted immunomodulatory therapies. Conclusions from the workshop were as follows. 1) While profound altered immunity can promote tumorigenesis, not all components of the immune system are equally important in defense against or promotion of cancer and a similar cancer risk for all immunomodulatory molecules should not be assumed. 2) Rodent carcinogenicity studies have limitations and are generally not reliable predictors of cancer risk associated with immunosuppression. 3) Cancer risk needs to be evaluated based on mechanism-based weight-of-evidence, including data from immune function tests most relevant to tumor immunosurveillance or promotion. 4) Information from nonclinical experiments, clinical epidemiology and immunomodulatory therapeutics show that immunosurveillance involves a complex network of cells and mediators. To support a weight-of-evidence approach, an increased focus on understanding the quantitative relationship between changes in relevant immune function tests and cancer risk is needed.

Small PARP inhibitor PJ-34 induces cell cycle arrest and apoptosis of adult T-cell leukemia cells

Background

HTLV-I is associated with the development of an aggressive form of lymphocytic leukemia known as adult T-cell leukemia/lymphoma (ATLL). A major obstacle for effective treatment of ATLL resides in the genetic diversity of tumor cells and their ability to acquire resistance to chemotherapy regimens. As a result, most patients relapse and current therapeutic approaches still have limited long-term survival benefits. Hence, the development of novel approaches is greatly needed.

Methods

In this study, we found that a small molecule inhibitor of poly (ADP-ribose) polymerase (PARP), PJ-34, is very effective in activating S/G2M cell cycle checkpoints, resulting in permanent cell cycle arrest and reactivation of p53 transcription functions and caspase-3-dependent apoptosis of HTLV-I-transformed and patient-derived ATLL tumor cells. We also found that HTLV-I-transformed MT-2 cells are resistant to PJ-34 therapy associated with reduced cleaved caspase-3 activation and increased expression of RelA/p65.

Conclusion

Since PJ-34 has been tested in clinical trials for the treatment of solid tumors, our results suggest that some ATLL patients may be good candidates to benefit from PJ-34 therapy.

The Emerging Role of miRNAs in HTLV-1 Infection and ATLL Pathogenesis

Human T-cell leukemia virus (HTLV)-1 is a human retrovirus and the etiological agent of adult T-cell leukemia/lymphoma (ATLL), a fatal malignancy of CD4/CD25+ T lymphocytes. In recent years, cellular as well as virus-encoded microRNA (miRNA) have been shown to deregulate signaling pathways to favor virus life cycle. HTLV-1 does not encode miRNA, but several studies have demonstrated that cellular miRNA expression is affected in infected cells. Distinct mechanisms such as transcriptional, epigenetic or interference with miRNA processing machinery have been involved. This article reviews the current knowledge of the role of cellular microRNAs in virus infection, replication, immune escape and pathogenesis of HTLV-1.

Estimation of the infectious viral load required for transfusion-transmitted human T-lymphotropic virus type 1 infection (TT-HTLV-1) and of the effectiveness of leukocyte reduction in preventing TT-HTLV-1

BACKGROUND AND OBJECTIVES

The risk of transfusion-transmitted human T-lymphotropic virus type 1 infection (TT-HTLV-1) after prestorage leucocyte reduction (LR) remains unknown, as the proviral load in the blood component that would cause TT-HTLV-1 is undetermined. On the basis of the distribution of HTLV-1 proviral load among HTLV-1-sero-positive blood donors, we attempted to estimate the proviral load for transfusion-related infectivity. We also discuss the effectiveness of LR in preventing TT-HTLV-1.

MATERIALS AND METHODS

The HTLV-1 proviral load in 300 HTLV-1-sero-positive blood donors was determined by real-time polymerase chain reaction analysis. The proviral load required for transfusion-related infectivity was estimated using historical TT-HTLV-1 frequency data from a retrospective study on patients who had received blood from HTLV-1-sero-positive blood donors and the distribution pattern of HTLV-1 proviral load among blood donors.

RESULTS

HTLV-1 proviral loads ranged between < 0.01 and 25.0 copies per 100 leucocytes. Historical data showed TT-HTLV-1 frequency to be 80%. Assuming that 80% of the 300 sero-positive samples are infectious, it is estimated that the transfer of ≥ 9 × 10(4) cells containing the HTLV-1 provirus is required to establish TT-HTLV-1.

CONCLUSION

The residual number of HTLV-1-infected cells after LR is substantially lower than the viral load necessary for TT-HTLV-1. LR therefore appears to be effective in minimizing the incidence of TT-HTLV-1.

Multifaceted adult T-cell leukemia/lymphoma in India: a case series

Background:

Adult T-cell leukemia/lymphoma (ATL) is caused by human T-cell lymphotropic virus type-1 (HTLV-1). India is considered as a nonendemic region for HTLV-1. Recent upsurge of cases have been noted in southern parts of India.

Aims and objectives:

The objective was to describe skin manifestations in various types of ATL.

Materials and Methods:

Clinical examination, blood investigations, skin biopsies, lymph node biopsies, and immunohistochemistry were performed in five patients. Flow cytometry was performed in two cases.

Results:

Serological testing was positive for HTLV-1 in all patients. All patients presented with skin lesions. Rare presentations of molluscum contagiosum like papules, purpuric macules and plaques, hypopigmented macules and verrucous papules were seen. Dermatophytic infections occurred in two patients. Mucosal lesion was seen in one patient. Histological features include dermal lymphoid infiltrate with or without epidermotropism. Presence of epidermotropism did not correlate with the severity of disease. All patients except one succumbed to illness within few months to 1 year period.

Conclusions:

ATL manifest in myriad presentations and skin lesions are often the earliest manifestation. Cutaneous manifestations of ATL vary from subtle hypopigmented macules to florid nodular lesions, and HTLV-1 screening need to be carried out in all doubtful cases.

Therapeutic microRNAs targeting the NF-kappa B signaling circuits of cancers

MicroRNAs (miRNAs) not only directly regulate NF-κB expression, but also up- or down-regulate NF-κB activity via upstream and downstream signaling pathways of NF-κB. In many cancer cells, miRNA expressions are altered accompanied with an elevation of NF-κB activity, which often plays a role in promoting cancer development and progression as well as hindering the effectiveness of chemo and radiation therapies. Thus NF-κB-targeting miRNAs have been identified and characterized as potential therapeutics for cancer treatment and sensitizers of chemo and radiotherapies. However, due to cross-targeting and instability of miRNAs, some limitations of using miRNA as cancer therapeutics still exist. In this review, the mechanisms for miRNA-mediated alteration of NF-κB expression and activation in different types of cancers will be discussed. The results of therapeutic use of NF-κB-targeting miRNA for cancer treatment will be examined. Some limitations, challenges and potential strategies in future development of miRNA as cancer therapeutics are also assessed.

CD160 expression defines a uniquely exhausted subset of T lymphocytes in HTLV-1 infection

HTLV-1 infection is a life-long retroviral infection. Chronic viral antigenic stimulation induces persistent infection which results in a clinically asymptomatic carrier state. Only a minor proportion of infected individuals develop adult T cell leukemia/lymphoma (ATLL) or HTLV-1-associated myelopathy/tropical spastic myelopathy (HAM/TSP). This is dependent on a balance of host and genetic factors. CD8+ cytotoxic T lymphocyte function is important in the immune response against viral infection; however, the contribution of CD160 receptor associated with CD8+ T lymphocytes is unclear. Thus, we sought to decipher its role on CTL function in HTLV-1 infection. Here, we report high frequencies of CD160 on CD8+ T cells, with significantly higher levels on HTLV-1 specific CD8+ T cells. Intercepting the CD160 pathway via blockade of the receptor or its ligand, herpes virus entry mediator (HVEM) resulted in improved perforin production and CD107a degranulation of HTLV-1 specific CD8+ T cells. Analysis of the CD160-expressing CD8+ cells demonstrated a unique subset associated with a highly differentiated effector memory based on CD45RA and CCR7 co-expression, increased expression of inhibitory molecules, 2B4 and PD1. Altogether, these results suggest a role for CD160/HVEM pathway in regulating immune response against HTLV-1 infection which may prove promising in the development of immune therapies for the treatment of HTLV-1 infection and other associated disorders.

HTLV-1 bZIP factor supports proliferation of adult T cell leukemia cells through suppression of C/EBPα signaling

BACKGROUND

Human T-cell leukemia virus type 1 (HTLV-1) is an oncogenic retrovirus etiologically associated with adult T-cell leukemia (ATL). The HTLV-1 bZIP factor (HBZ), which is encoded by minus strand of provirus, is expressed in all ATL cases and supports the proliferation of ATL cells. However, the precise mechanism of growth promoting activity of HBZ is poorly understood.

RESULTS

In this study, we showed that HBZ suppressed C/EBPα signaling activation induced by either Tax or C/EBPα. As mechanisms of HBZ-mediated C/EBPα inhibition, we found that HBZ physically interacted with C/EBPα and diminished its DNA binding capacity. Luciferase and immunoprecipitation assays revealed that HBZ repressed C/EBPα activation in a Smad3-dependent manner. In addition, C/EBPα was overexpressed in HTLV-1 infected cell lines and fresh ATL cases. HBZ was able to induce C/EBPα transcription by enhancing its promoter activity. Finally, HBZ selectively modulated the expression of C/EBPα target genes, leading to the impairment of C/EBPα-mediated cell growth suppression.

CONCLUSION

HBZ, by suppressing C/EBPα signaling, supports the proliferation of HTLV-1 infected cells, which is thought to be critical for oncogenesis.

Reduced level of the BCL11B protein is associated with adult T-cell leukemia/lymphoma

Background

Adult T-cell leukemia/lymphoma (ATLL) develops in a small proportion of human T-cell leukemia virus type I (HTLV-I)-infected individuals. However, the mechanism by which HTLV-I causes ATLL has not been fully elucidated. To provide fundamental insights into the multistep process of leukemogenesis, we have mapped the chromosomal abnormalities in 50 ATLL cases to identify potential key regulators of ATLL.

Results

The analysis of breakpoints in one ATLL case with the translocations t(14;17)(q32;q22-23) resulted in the identification of a Kruppel zinc finger gene, BCL11B, which plays a crucial role in T-cell development. Among the 7 ATLL cases that we examined by immunofluorescence analysis, 4 displayed low and one displayed moderate BCL11B signal intensities. A dramatically reduced level of the BCL11B protein was also found in HTLV-I-positive T-cell lines. The ectopic expression of BCL11B resulted in significant growth suppression in ATLL-derived cell lines but not in Jurkat cells.

Conclusions

Our genetic and functional data provide the first evidence that a reduction in the level of the BCL11B protein is a key event in the multistep progression of ATLL leukemogenesis.

Increased risk of histologically defined cancer subtypes in human immunodeficiency virus-infected individuals: clues for possible immunosuppression-related or infectious etiology

BACKGROUND

Malignancies that occur in excess among human immunodeficiency virus (HIV)-infected individuals may be caused by immunosuppression or infections. Because histologically defined cancer subtypes have not been systematically evaluated, their risk was assessed among people with acquired immunodeficiency syndrome (AIDS).

METHODS

Analyses included 569,268 people with AIDS from the HIV/AIDS Cancer Match Study, a linkage of 15 US population-based HIV/AIDS and cancer registries during 1980 to 2007. Standardized incidence ratios (SIRs) were estimated to compare cancer risk in people with AIDS to the general population overall, and stratified by age, calendar period (a proxy of changing HIV therapies), and time since onset of AIDS (a proxy of immunosuppression).

RESULTS

Sixteen individual cancer histologies or histology groupings manifested significantly elevated SIRs. Risks were most elevated for adult T cell leukemia/lymphoma (SIR = 11.3), neoplasms of histiocytes and accessory lymphoid cells (SIR = 10.7), giant cell carcinoma (SIR = 7.51), and leukemia not otherwise specified (SIR = 6.69). SIRs ranged from 1.4 to 4.6 for spindle cell carcinoma, bronchioloalveolar adenocarcinoma, adnexal and skin appendage neoplasms, sarcoma not otherwise specified, spindle cell sarcoma, leiomyosarcoma, mesothelioma, germ cell tumors, plasma cell tumors, immunoproliferative diseases, acute lymphocytic leukemia, and myeloid leukemias. For several of these cancer subtypes, significant declines in SIRs were observed across calendar periods (consistent with decreasing risk with improved HIV therapies) or increase in SIRs with time since onset of AIDS (ie, prolonged immunosuppression).

CONCLUSIONS

The elevated risk of certain cancer subtypes in people with AIDS may point to an etiologic role of immunosuppression or infection. Future studies are needed to further investigate these associations and evaluate candidate infectious agents.

Adult T-cell leukemia/lymphoma: a retroviral malady

Adult T-cell leukemia/lymphoma (ATLL) is an aggressive leukemia/lymphoma of mature T-lymphocytes caused by human T-cell lymphotropic virus type 1 (HTLV-1). At a tertiary healthcare center in South India, a 58-year-old female presented with multiple erythematous, crusted, and umbilicated papules over the body along with cervical lymphadenopathy. The skin biopsy was consistent with cutaneous T-cell lymphoma. Although she responded initially to chemotherapy, the disease relapsed after 3 months, and she developed disseminated infiltrated skin lesions, generalized lymphadenopathy, and leukemia. Due to the unusual clinical findings we did HTLV-1 Enzyme-linked immunosorbent assay (ELISA), which turned out to be positive in high titers. Her mother had died at an early age from a hematological malignancy and her daughter was also found to be seropositive. To the best of our knowledge, this is the first case to be reported from India of the chronic type of ATLL associated with mother-to-child transmission of HTLV-1 in two generations. This case also emphasizes that the chronic type of ATLL can occur in nonendemic areas like India and should be suspected in nonresponding cases of mycosis fungoides. It should be kept in mind that the chronic type often presents without hypercalcemia or the characteristic ‘flower cells’ in the peripheral smear.

Patterns of and hypotheses for infection-related cancers in a Chinese population with rapid economic development

With economic development, non-communicable diseases replace infectious diseases as the leading cause of death; how such transition occurs for infectious diseases with long latency has rarely been considered. We took advantage of a Chinese population with rapid economic development in the mid-20th century to study changing patterns of infection-related cancers. We used sex-specific Poisson regression to estimate age, period and cohort effects on adult deaths 1976-2005 from eight infection-related cancers in Hong Kong. Cervical, head and neck, and oesophageal cancers, associated with sexually transmitted infections, decreased for the first birth cohorts with sexual debut in a more developed environment. Leukaemia and non-Hodgkin's lymphoma, associated with vertically transmitted infections, decreased for the first cohorts born into a more developed environment. Birth cohort patterns were unclear for nasopharyngeal, stomach and liver cancers. Mortality rates for cancers related to early infections may depend on population history, with delayed reductions for some infection-related cancers.

Human T-lymphotropic virus 1 (HTLV-1) infection--dermatological implications

Human T-lymphotropic virus type 1 (HTLV-1) is a type C retrovirus primarily endemic to Japan, Central and South America, the Middle East, regions of Africa, and the Caribbean. Currently, an estimated 10-20 million people worldwide are infected with this virus. Although the majority of infected individuals remain asymptomatic, HTLV-1 is the causative agent of a number of disorders, notably adult T-cell leukemia/lymphoma (ATLL) and a progressive demyelinating neurological disorder, HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). In addition to ATLL and HAM/TSP, HTLV-1 has been associated with a spectrum of skin disorders, such as infective dermatitis associated with HTLV-1, crusted scabies, and leprosy. The understanding of the interaction between virus and host response has improved markedly, but there are still few treatment options.

Viral oncogenesis and its role in nonmelanoma skin cancer

In recent years, the contribution of viruses to cutaneous oncogenesis has steadily gained recognition. The archetype is human herpesvirus 8, which is well established as the causative agent in Kaposi sarcoma. Other viruses believed to play a role in nonmelanoma skin cancer include human papillomavirus and the recently described Merkel cell polyomavirus. We review the mechanisms by which these three viruses interact with the host cell, ultraviolet radiation and immunosuppression to result in carcinogenesis.

Design and synthesis of several small-size HTLV-I protease inhibitors with different hydrophilicity profiles

The human T cell leukemia/lymphotropic virus type 1 (HTLV-I) is clinically associated with adult T cell leukemia/lymphoma, HTLV-I associated myelopathy/tropical spastic paraparesis, and a number of other chronic inflammatory diseases. To stop the replication of the virus, we developed highly potent tetrapeptidic HTLV-I protease inhibitors. In a recent X-ray crystallography study, several of our inhibitors could not form co-crystal complexes with the protease due to their high hydrophobicity. In the current study, we designed, synthesized and evaluated the HTLV-I protease inhibition potency of compounds with hydrophilic end-capping moieties with the aim of improving pharmaceutic and pharmacokinetic properties.

Leukemic T cells are specifically enriched in a unique CD3(dim) CD7(low) subpopulation of CD4(+) T cells in acute-type adult T-cell leukemia

The morphological discrimination of leukemic from non-leukemic T cells is often difficult in adult T-cell leukemia (ATL) as ATL cells show morphological diversity, with the exception of typical "flower cells." Because defects in the expression of CD3 as well as CD7 are common in ATL cells, we applied multi-color flow cytometry to detect a putative leukemia-specific cell population in the peripheral blood from ATL patients. CD4(+) CD14(-) cells subjected to two-color analysis based on a CD3 vs CD7 plot clearly demonstrated the presence of a CD3(dim) CD7(low) subpopulation in each of nine patients with acute-type ATL. The majority of sorted cells from this fraction showed a flower cell-like morphology and carried a high proviral load for the human T-cell leukemia virus type 1 (HTLV-I). Genomic integration site analysis (inverse long-range PCR) and analysis of the T cell receptor Vβ repertoire by flow cytometry indicated that the majority of leukemia cells were included in the CD3(dim) CD7(low) subpopulation. These results suggest that leukemic T cells are specifically enriched in a unique CD3(dim) CD7(low) subpopulation of CD4(+) T cells in acute-type ATL.

Maintaining potent HTLV-I protease inhibition without the P3-cap moiety in small tetrapeptidic inhibitors

The human T cell lymphotropic/leukemia virus type 1 (HTLV-I) causes adult T cell lymphoma/leukemia. The virus is also responsible for chronic progressive myelopathy and several inflammatory diseases. To stop the manufacturing of new viral components, in our previous reports, we derived small tetrapeptidic HTLV-I protease inhibitors with an important amide-capping moiety at the P(3) residue. In the current study, we removed the P(3)-cap moiety and, with great difficulty, optimized the P(3) residue for HTLV-I protease inhibition potency. We discovered a very potent and small tetrapeptidic HTLV-I protease inhibitor (KNI-10774a, IC(50)=13 nM).

Pathobiology of mature T-cell lymphomas

Mature T- and natural killer (NK)-cell neoplasms are relatively rare forms of leukemia/lymphoma. The diagnosis of these entities is often difficult, necessitating extensive immunophenotypic, molecular, and genetic testing. Despite the accumulating information on the pathobiology of these neoplasms, in many cases the prognosis remains poor. This article presents an updated view of the morphologic, immunophenotypic, genetic, and molecular characteristics of the mature T- and NK-cell neoplasms. For a better understanding of this complex topic, the development of normal T and NK cells is briefly discussed. The presentation of the characteristic features of the neoplasms in the 2008 World Health Organization classification of hematopoietic neoplasms includes advances in the understanding of the pathobiology of each diagnostic category.

HTLV-1 and apoptosis: role in cellular transformation and recent advances in therapeutic approaches

A universal cellular defense mechanism against viral invasion is the elimination of infected cells through apoptotic cell death. To counteract host defenses many viruses have evolved complex apoptosis evasion strategies. The oncogenic human retrovirus HTLV-1 is the etiological agent of adult-T-cell leukemia/lymphoma (ATLL) and the neurodegenerative disease known as HTLV-associated myelopathy/tropical spastic paraparesis (HAM/TSP). The poor prognosis in HTLV-1-induced ATLL is linked to the resistance of neoplastic T cells against conventional therapies and the immuno-compromised state of patients. Nevertheless, several studies have shown that the apoptotic pathway is largely intact and can be reactivated in ATLL tumor cells to induce specific killing. A better understanding of the molecular mechanisms employed by HTLV-1 to counteract cellular death pathways remains an important challenge for future therapies and the treatment of HTLV-1-associated diseases.

Adult T-cell leukemia/lymphoma in a patient from Romania: a case report and review of the literature

Adult T-cell leukemia/lymphoma (ATLL) is a rare malignancy caused by human T-cell leukemia virus-1. ATLL is endemic to Japan, and to date, there are only four case reports of patients from Romania who have developed ATLL. Here, we describe a woman living in Madison, Wisconsin, originally from Romania, who presented with an atypical papulosquamous eruption and was ultimately diagnosed with smoldering ATLL. Narrow-band ultraviolet-B (UV-B) therapy and mid-potency topical steroids resulted in skin clearing for approximately 5 months after diagnosis; however, she subsequently relapsed with disease refractory to both narrow band UV-B and psoralen plus ultraviolet A (PUV-A), progressed to acute ATLL and expired secondary to complications.

Adult T-cell Leukemia/Lymphoma: First case report from Qatar

In what appears to be the first case of Adult T-cell Leukemia|Lymphoma (ATLL) reported in Qatar and Middle Eastern Arab countries, a 39-year-old lady presented first with Pneumocystis carinii pneumonia and hypercalcaemia and later showed the full picture of ATLL, splenomegaly leukocytosis, skin rash, and bone marrow infiltrations. She responded well to chemotherapy, with complete remission after four cycles of combination chemotherapy but the prognosis of patients with ATLL is poor. Although patients may respond initially to treatment with combination chemotherapy regimens devised for advanced, aggressive Non-Hodgkin's Lymphoma (NHL), relapses are common with a median survival of eight months and a four-year survival of 12 percent.

Locking the two ends of tetrapeptidic HTLV-I protease inhibitors inside the enzyme

Adult T-cell leukemia and tropical spastic paraparesis/HTLV-I-associated myelopathy are only some of the more common end results of an infection with a human T-cell leukemia virus type 1 (HTLV-I). Expanding from our previous reports, we synthesized all different permutations of tetrapeptidic HTLV-I protease inhibitors using at least eight P(3)-cap and five P(1)(')-cap moieties. The inhibitors exhibited over 97% inhibition against HIV-1 protease and a wide range of inhibitory activity against HTLV-I protease.

Synthesis and activity of tetrapeptidic HTLV-I protease inhibitors possessing different P3-cap moieties

The causative agent behind adult T-cell leukemia and tropical spastic paraparesis/HTLV-I-associated myelopathy is the human T-cell leukemia virus type 1 (HTLV-I). Tetrapeptidic HTLV-I protease inhibitors were designed on a previously reported potent inhibitor KNI-10516, with modifications at the P(3)-cap moieties. All the inhibitors showed high HIV-1 protease inhibitory activity (over 98% inhibition at 50nM) and most exhibited highly potent inhibition against HTLV-I protease (IC(50) values were less than 100nM).

Sustained hematologic and central nervous system remission with single-agent denileukin diftitox in refractory adult T-cell leukemia/lymphoma

Human T-lymphotrophic virus-1-associated adult T-cell leukemia/lymphoma (ATLL) is a rare and often fatal disease. Initial treatment often includes zidovudine/interferon (IFN)-based therapy, although disease remission is typically not complete or durable. This study reports on a 55-year-old man with relapsed/refractory leukemic-phase ATLL including significant central nervous system (CNS) disease with resistance to previous zidovudine/IFN and arsenic trioxide/IFN treatment. The patient experienced a rapid hematologic and CNS clinical response with single-agent denileukin diftitox therapy (18 microg/kg per day for 5 days). He tolerated 8 cycles of denileukin diftitox therapy well and experienced a sustained complete hematologic and CNS remission. The patient subsequently underwent matched sibling reduced-intensity allogeneic transplantation and remains disease free. Further study examining denileukin diftitox in patients with relapsed/refractory ATLL is warranted.

New insights into the pathogenesis, diagnosis and treatment of human T-cell leukemia virus type 1-induced disease

It has been over 25 years since the discovery of human T-cell leukemia virus type 1 (HTLV-1); however, the exact sequence of events that occur during primary infection, clinical latency or the development of disease remains unresolved. The advances in molecular virology and neuroimmunology have contributed significantly to our understanding of HTLV-1 pathogenesis, but also uncovered the complexity of the virus–host interaction both in the peripheral blood and the CNS. Here, we overview the general pathologic features of HTLV-1, molecular mechanisms of oncogenic transformation and characteristics of the host immune response during the associated neuroinflammatory process. We also discuss both current and new approaches in the diagnosis and therapy of HTLV-1 associated diseases – adult T-cell leukemia and HTLV-1-associated myelopathy/tropical spastic paraparesis. Finally, potentially important emerging areas of research that may have an impact on our understanding of the pathogenic mechanism have been briefly introduced.

Severe hypercalcaemia and lymphoma in an HTLV-1 positive Jamaican woman: a case report

Human T cell lymphotrophic virus type-1 infection is endemic in the Afro-Caribbean community in Britain, with carriage rates of about 3%. Although there is a long latency, carriers have a 1–5% chance of developing adult T cell leukaemia/lymphoma, a condition frequently complicated by marked and refractory hypercalcaemia, and with a poor prognosis. We present the case of an elderly Jamaican woman with severe hypercalcaemia and a raised PTHrP who was found to have lymphoma and was positive for HTLV-1.