Clinical Trials and Treatment of ATL

Zidovudine and Interferon Alfa based regimens for the treatment of adult T-cell leukemia/lymphoma (ATLL): a systematic review and meta-analysis

BACKGROUND

ATLL (Adult T-Cell Leukemia/Lymphoma) is an aggressive hematological malignancy. This T-cell non-Hodgkin lymphoma, caused by the human T-cell leukemia virus type 1 (HTLV-1), is challenging to treat. There is no known treatment for ATLL as of yet. However, it is recommended to use Zidovudine and Interferon Alfa-based regimens (AZT/IFN), chemotherapy, and stem cell transplant. This study aims to review the outcome of patients with different subtypes of ATLL treated with Zidovudine and Interferon Alfa-based regimens.

METHODS

A systematic search was carried out for articles evaluating outcomes of ATLL treatment by AZT/IFN agents on human subjects from January 1, 2004, until July 1, 2022. Researchers assessed all studies regarding the topic, followed by extracting the data. A random-effects model was used in the meta-analyses.

RESULTS

We obtained fifteen articles on the AZT/IFN treatment of 1101 ATLL patients. The response rate of the AZT/IFN regimen yielded an OR of 67% [95% CI: 0.50; 0.80], a CR of 33% [95% CI: 0.24; 0.44], and a PR of 31% [95% CI: 0.24; 0.39] among individuals who received this regimen at any point during their treatment. Our subgroup analyses' findings demonstrated that patients who received front-line and combined AZT/IFN therapy responded better than those who received AZT/IFN alone. It is significant to note that patients with indolent subtypes of disease had considerably higher response rates than individuals with aggressive disease.

CONCLUSION

IFN/AZT combined with chemotherapy regimens is an effective treatment for ATLL patients, and its use in the early stages of the disease may result in a greater response rate.

Pathologically Proven Intraocular Infiltration With Adult T-Cell Leukemia/Lymphoma: Two New Cases With Either Vitreous Opacity or Aqueous Hypopyon and Literature Review of 16 Cases

This study reported 2 new patients and 16 historical cases with pathologically proven intraocular infiltration with adult T-cell leukemia and lymphoma (ATLL) to know the timing of intraocular infiltration in the disease course. The first case was a 67-year-old woman who developed bilateral vitreous opacity about half a year after the onset of acute type of ATLL that had been unresponsive to chemotherapy. She underwent vitrectomy combined with cataract surgery in both eyes. She had bilateral optic disc atrophy and localized retinal white infiltrates in both eyes. Cytological examination of vitreous aspirates demonstrated medium-sized cells with aberrant flower-like convoluted nuclei, positive for CD3, and thus indicative of T-cells. The second case was a 38-year-old man who was diagnosed acute type of ATLL at the presentation of acute kidney injury. About half a year after initial chemotherapy and allogeneic hematopoietic stem cell transplantation, he developed aqueous hypopyon in the right eye, concurrent with cutaneous and central nervous system relapse. Aqueous tap disclosed class V abnormal cells. The aqueous “pseudohypopyon” resolved in response to another round of chemotherapy with mogamulizumab. In review of 18 patients, intraocular infiltration with ATLL was diagnosed by vitrectomy in 9, aqueous tap in 3, chorioretinal biopsy in 3, and autopsy in 3. The intraocular infiltration developed concurrently with systemic diagnosis of ATLL in 5 patients, but developed later after chemotherapy in 13. In conclusion, intraocular infiltration with ATLL appears rare, and pathological diagnosis by vitrectomy and aqueous tap would help determine therapeutic plan in relapse after chemotherapy.

Immunophenotypic analysis of cerebrospinal fluid reveals concurrent development of ATL in the CNS of a HAM/TSP patient

Both adult T-cell leukemia/lymphoma (ATL) and human T-cell leukemia virus type 1 (HTLV-1)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) can be induced by HTLV-1, but concurrent development has been rarely reported. We present the case of a 55-year-old female who developed cranial nerve symptoms after a 20-year history of HAM/TSP. Although multiple white matter lesions were observed on brain magnetic resonance imaging, no abnormalities were seen on a systemic computed tomography scan. Quantitative flow-cytometric analysis of cell populations in the cerebrospinal fluid (CSF) revealed that most of the infiltrating cells were not inflammatory cells, but HTLV-1-infected CD4⁺ CADM-1⁺ T-cells completely lacking CD7 expression. As stepwise downregulation of CD7 is correlated with disease progression from HTLV-1 carrier to aggressive ATL, the CSF cells were classified as aggressive ATL; these cells exhibited a more progressed phenotype than those in peripheral blood (PB). HAM/TSP disease activity was estimated to be low. From these and other examinations, we made a diagnosis of acute-type ATL, which unusually developed in the central nervous system at initial onset prior to systemic progression. In ATL cases with a challenging diagnosis, immunophenotypic characterization of CSF and PB is valuable for differential diagnosis and understanding disease status.

Clinical Features, Pathological Features, and Treatment Outcomes of 22 Patients with Aggressive Adult T-cell Leukemia-lymphoma Treated with a Humanized CCR4 Antibody (Mogamulizumab) at a Single Institution during a 6-year Period (2012-2018)

Objective To elucidate the clinical impact of humanized CCR4 antibody (mogamulizumab) on adult T-cell leukemia-lymphoma (ATL), we retrospectively analyzed the clinical and pathological features and treatment outcomes of aggressive ATL. Methods Twenty-two patients (median age: 65 years) with aggressive ATL [acute- (n=16) or lymphoma-type (n=6)] had their characteristics analyzed. All cases were treated with mogamulizumab at our institution from 2012 to 2018. In addition, we subjected 14 specimens of ATL to histological, immunological, and genetic analyses. Results Regarding the patient outcomes, the overall response rates were 68.1% and 31.8% after 4 and 8 courses (or after the final courses), respectively. The median overall survival (OS) was 95.5 days, while the OS rates at 6 and 12 months were 31.5% and 21.1%, respectively. Concerning patient pathological characteristics, 6 of the 14 patients examined (42.9%) had CCR4 mutations. Regarding the clinicopathological findings related to the mogamulizumab response, notably, the cases with somatic CCR4 mutation tended to have a poorer response (16.7%) than those with wild-type CCR4 (62.5%) after 4 cycles of mogamulizumab. Furthermore, the CCR4 global score tended to be higher in the responder cases than in the non-responder cases. Conclusion The present findings suggest that the CCR4 expression may be related to the mogamulizumab response, although no other significant predictive markers were identified in this study. Further studies will be needed in order to identify more markers related to the mogamulizumab response.

MEF-2 isoforms' (A-D) roles in development and tumorigenesis

Myocyte enhancer factor (MEF)-2 plays a critical role in proliferation, differentiation, and development of various cell types in a tissue specific manner. Four isoforms of MEF-2 (A-D) differentially participate in controlling the cell fate during the developmental phases of cardiac, muscle, vascular, immune and skeletal systems. Through their associations with various cellular factors MEF-2 isoforms can trigger alterations in complex protein networks and modulate various stages of cellular differentiation, proliferation, survival and apoptosis. The role of the MEF-2 family of transcription factors in the development has been investigated in various cell types, and the evolving alterations in this family of transcription factors have resulted in a diverse and wide spectrum of disease phenotypes, ranging from cancer to infection. This review provides a comprehensive account on MEF-2 isoforms (A-D) from their respective localization, signaling, role in development and tumorigenesis as well as their association with histone deacetylases (HDACs), which can be exploited for therapeutic intervention.

Cytokine Networks Dysregulation during HTLV-1 Infection and Associated Diseases

Human T-cell leukemia virus type 1 (HTLV-1) is the causative agent of a neural chronic inflammation, called HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) and of a malignant lymphoproliferation, called the adult T-cell leukemia/lymphoma (ATLL). The mechanisms through which the HTLV-1 induces these diseases are still unclear, but they might rely on immune alterations. HAM/TSP is associated with an impaired production of pro-inflammatory cytokines and chemokines, such as IFN-γ, TNF-α, CXCL9, or CXCL10. ATLL is associated with high levels of IL-10 and TGF-β. These immunosuppressive cytokines could promote a protumoral micro-environment. Moreover, HTLV-1 infection impairs the IFN-I production and signaling, and favors the IL-2, IL-4, and IL-6 expression. This contributes both to immune escape and to infected cells proliferation. Here, we review the landscape of cytokine dysregulations induced by HTLV-1 infection and the role of these cytokines in the HTLV-1-associated diseases progression.

The small molecule STF-62247 induces apoptotic and autophagic cell death in leukemic cells

Adult T cell leukemia/lymphoma (ATL) is an aggressive malignant T cell disease caused by human T cell leukemia virus-I (HTLV-1). Treatment outcomes for aggressive subtypes of ATL remain poor, with little improvement in overall survival since HTLV-1 was discovered. Therefore, new therapeutic strategies for ATL are required. STF-62247 induces autophagy and selectively kills renal cell carcinoma without apoptotic cell death. Here, we demonstrate that STF-62247 reduced cell viability and resulted in autophagosome accumulation and autophagy in leukemic cell lines (S1T, MT-2, and Jurkat). Interestingly, STF-62247 induced apoptosis in HTLV-1-infected cell lines (S1T and MT-2), as indicated by DNA fragmentation and caspase activation, but not in non-HTLV-1-infected Jurkat cells; a caspase inhibitor did not prevent this caspase-associated cell death. STF-62247 also increased nuclear endonuclease G levels. Furthermore, STF-62247 reduced cell viability and increased the number of apoptotic cells in peripheral blood mononuclear cells collected from patients with acute ATL, which has a poor prognosis. Therefore, STF-62247 may have novel therapeutic potential for ATL. This is the first evidence to demonstrate the cell growth-inhibitory effect of an autophagy inducer by caspase-dependent apoptosis and caspase-independent cell death via autophagy and endonuclease G in leukemic cells.

HTLV-1, the Other Pathogenic Yet Neglected Human Retrovirus: From Transmission to Therapeutic Treatment

Going back to their discovery in the early 1980s, both the Human T-cell Leukemia virus type-1 (HTLV-1) and the Human Immunodeficiency Virus type-1 (HIV-1) greatly fascinated the virology scene, not only because they were the first human retroviruses discovered, but also because they were associated with fatal diseases in the human population. In almost four decades of scientific research, both viruses have had different fates, HTLV-1 being often upstaged by HIV-1. However, although being very close in terms of genome organization, cellular tropism, and viral replication, HIV-1 and HTLV-1 are not completely commutable in terms of treatment, especially because of the opposite fate of the cells they infect: death versus immortalization, respectively. Nowadays, the antiretroviral therapies developed to treat HIV-1 infected individuals and to limit HIV-1 spread among the human population have a poor or no effect on HTLV-1 infected individuals, and thus, do not prevent the development of HTLV-1-associated diseases, which still lack highly efficient treatments. The present review mainly focuses on the course of HTLV-1 infection, from the initial infection of the host to diseases development and associated treatments, but also investigates HIV-1/HTLV-1 co-infection events and their impact on diseases development.

Adult T-cell leukemia cell-induced uveitis: rapid increase in adult T-cell leukemia cells disrupts the blood-ocular barrier

Adult T-cell leukemia-lymphoma (ATL), a rare lymphoid malignancy with a high mortality rate, is caused by the human T-cell leukemia virus type 1. Due to its rarity and poor prognosis, ocular manifestations have yet to be well documented. The mechanisms that underlie ocular involvement in ATL patients, thus, remain poorly understood. We report the first successfully tracked case of ocular inflammation (i.e., uveitis) that developed simultaneously in conjunction with a rapid increase in ATL cells. Our findings for this case suggest that a rapid increase in ATL cells contributed to the disruption of the blood-ocular barrier, which may, thus, represent one mechanism underlying the induction of uveitis in ATL patients. Furthermore, with the development of novel therapies, the longer survival times of ATL patients have raised new issues, such as quality of vision in ATL patients. Hematologists should be aware that a rapid increase in the number of ATL cells may cause adult T-cell leukemia cell-induced uveitis.

The Impact of a Humanized CCR4 Antibody (Mogamulizumab) on Patients with Aggressive-Type Adult T-Cell Leukemia-Lymphoma Treated with Allogeneic Hematopoietic Stem Cell Transplantation

Although a humanized CCR4 antibody (mogamulizumab) was reported to be effective for refractory adult T-cell leukemia-lymphoma (ATL), several reports regarding the use of mogamulizumab before allo-hematopoietic stem cell transplantation (HSCT) strongly indicated a high incidence of severe acute graft-versus-host-disease (GVHD) and treatment-related mortality (TRM). We retrospectively analyzed nine aggressive-type ATL patients who underwent allo-HSCT at a single institution in Miyazaki from 2006.1.1 to 2015.7.31. Among nine ATL patients, three had used mogamulizumab before treatment with allo-HSCT because of the poor control of refractory ATL. All three patients were treated with four to eight cycles of mogamulizumab. The interval from last administration of mogamulizumab to allo-HSCT was two to five months. All three patients with prior mogamulizumab treatment developed mild-moderate acute GVHD (grade 2) 28, 34, or 40 days after allo-HSCT. Acute GVHD was controlled by prednisolone treatment. Two patients in complete remission before allo-HSCT exhibited relatively prolonged survival (survival rate, 66%). Moreover, one patient developed human T-cell leukemia virus type 1-associated myelopathy-mimicking myelitis at five months after allo-HSCT. In contrast, two of six ATL patients without a history of mogamulizumab use survived (survival rate 33%). Thus, in cases of mogamulizumab use before treatment with allo-HSCT for refractory ATL, an appropriately long interval from the last administration of mogamulizumab to allo-HSCT may be one of factors to reduce TRM by acute GVHD, and to subsequently enhance graft-versus-tumor effects in ATL cases. Furthermore, caution is needed when administering mogamulizumab before allo-HSCT for severe GVHD and TRM.

Angiotensin II type 1 receptor blocker telmisartan induces apoptosis and autophagy in adult T-cell leukemia cells

Adult T‐cell leukemia/lymphoma (ATL), an aggressive T‐cell malignancy that develops after long‐term infection with human T‐cell leukemia virus (HTLV‐1), requires new treatments. Drug repositioning, reuse of a drug previously approved for the treatment of another condition to treat ATL, offers the possibility of reduced time and risk. Among clinically available angiotensin II receptor blockers, telmisartan is well known for its unique ability to activate peroxisome proliferator‐activated receptor‐γ, which plays various roles in lipid metabolism, cellular differentiation, and apoptosis. Here, telmisartan reduced cell viability and enhanced apoptotic cells via caspase activation in ex vivo peripheral blood monocytes from asymptomatic HTLV‐1 carriers (ACs) or via caspase‐independent cell death in acute‐type ATL, which has a poor prognosis. Telmisartan also induced significant growth inhibition and apoptosis in leukemia cell lines via caspase activation, whereas other angiotensin II receptor blockers did not induce cell death. Interestingly, telmisartan increased the LC3‐II‐enriched protein fraction, indicating autophagosome accumulation and autophagy. Thus, telmisartan simultaneously caused caspase activation and autophagy. A hypertension medication with antiproliferation effects on primary and leukemia cells is intriguing. Patients with an early diagnosis of ATL are generally monitored until the disease progresses; thus, suppression of progression from AC and indolent ATL to acute ATL is important. Our results suggest that telmisartan is highly effective against primary cells and leukemia cell lines in caspase‐dependent and ‐independent manners, and its clinical use may suppress acute transformation and improve prognosis of patients with this mortal disease. This is the first report demonstrating a cell growth‐inhibitory effect of telmisartan in fresh peripheral blood mononuclear cells from leukemia patients.

Establishment of a Therapeutic Anti-Pan HLA-Class II Monoclonal Antibody That Directly Induces Lymphoma Cell Death via Large Pore Formation

To develop a new therapeutic monoclonal Antibody (mAb) for Hodgkin lymphoma (HL), we immunized a BALB/c mouse with live HL cell lines, alternating between two HL cell lines. After hybridization, we screened the hybridoma clones by assessing direct cytotoxicity against a HL cell line not used for immunization. We developed this strategy for establishing mAb to reduce the risk of obtaining clonotypic mAb specific for single HL cell line. A newly established mouse anti-human mAb (4713) triggered cytoskeleton-dependent, but complement- and caspase-independent, cell death in HL cell lines, Burkitt lymphoma cell lines, and advanced adult T-cell leukemia cell lines. Intravenous injection of mAb 4713 in tumor-bearing SCID mice improved survival significantly. mAb 4713 was revealed to be a mouse anti-human pan-HLA class II mAb. Treatment with this mAb induced the formation of large pores on the surface of target lymphoma cells within 30 min. This finding suggests that the cell death process induced by this anti-pan HLA-class II mAb may involve the same death signals stimulated by a cytolytic anti-pan MHC class I mAb that also induces large pore formation. This multifaceted study supports the therapeutic potential of mAb 4713 for various forms of lymphoma.

Clinical Impact of a Humanized CCR4 Antibody (Mogamulizumab) in 14 Patients with Aggressive Adult T-cell Leukemia-lymphoma Treated at a Single Institution During a Three-year Period (2012-2014)

Objective We elucidated the effectiveness of a humanized CCR4 antibody (mogamulizumab) on adult T-cell leukemia-lymphoma (ATL), which typically has a poor outcome. Methods We retrospectively analyzed 14 patients with aggressive ATL who had been treated at our institution with weekly cycles of mogamulizumab for eight weeks from 2012-2014. Results The patients (median age: 63 years old) were classified as having acute- (n=10) or lymphoma-type (n=4) ATL. The prior treatment regimens consisted of CHOP, VCAP-AMP-VECP, DeVIC and CHASE, with an average of two courses (range: 1-4). The prior disease responses were partial remission (n=3) and progressive disease (n=11). The treatment was administered in the primary refractory setting (n=8), for relapse (n=2), or as bridging therapy before hematopoietic stem cell transplantation (n=4). The overall response rates were 64% and 43% after four and eight cycles (or after the final cycles), respectively. The median overall survival (OS), OS rate at six months and OS rate at 12 months were 66 days, 41.7% and 20.8%, respectively. All of the patients with acute-type ATL who showed a response to treatment had an early response. Notably, six of the 14 ATL patients showed somewhat prolonged survival (>100 days). However, relapse or disease progression in the peripheral blood, central nervous system, lymph nodes, skin, and/or bone occurred within a relatively short period after treatment. The adverse effects were tolerable, and included lymphopenia, cytomegalovirus infection and skin rash. Conclusion Mogamulizumab therapy resulted in an early and high remission rate and somewhat prolonged survival in patients with refractory ATL. However, the duration of remission was short, and there was early relapse and disease progression. This study may show the current impact of mogamulizumab in clinical practice.

Roles of HTLV-1 basic Zip Factor (HBZ) in Viral Chronicity and Leukemic Transformation. Potential New Therapeutic Approaches to Prevent and Treat HTLV-1-Related Diseases

More than thirty years have passed since human T-cell leukemia virus type 1 (HTLV-1) was described as the first retrovirus to be the causative agent of a human cancer, adult T-cell leukemia (ATL), but the precise mechanism behind HTLV-1 pathogenesis still remains elusive. For more than two decades, the transforming ability of HTLV-1 has been exclusively associated to the viral transactivator Tax. Thirteen year ago, we first reported that the minus strand of HTLV-1 encoded for a basic Zip factor factor (HBZ), and since then several teams have underscored the importance of this antisense viral protein for the maintenance of a chronic infection and the proliferation of infected cells. More recently, we as well as others have demonstrated that HBZ has the potential to transform cells both in vitro and in vivo. In this review, we focus on the latest progress in our understanding of HBZ functions in chronicity and cellular transformation. We will discuss the involvement of this paradigm shift of HTLV-1 research on new therapeutic approaches to treat HTLV-1-related human diseases.

Retargeting Oncolytic Vesicular Stomatitis Virus to Human T-Cell Lymphotropic Virus Type 1-Associated Adult T-Cell Leukemia

Adult T cell leukemia/lymphoma (ATL) is an aggressive cancer of CD4/CD25(+) T lymphocytes, the etiological agent of which is human T-cell lymphotropic virus type 1 (HTLV-1). ATL is highly refractory to current therapies, making the development of new treatments a high priority. Oncolytic viruses such as vesicular stomatitis virus (VSV) are being considered as anticancer agents since they readily infect transformed cells compared to normal cells, the former appearing to exhibit defective innate immune responses. Here, we have evaluated the efficacy and safety of a recombinant VSV that has been retargeted to specifically infect and replicate in transformed CD4(+) cells. This was achieved by replacing the single VSV glycoprotein (G) with human immunodeficiency virus type 1 (HIV-1) gp160 to create a hybrid fusion protein, gp160G. The resultant virus, VSV-gp160G, was found to only target cells expressing CD4 and retained robust oncolytic activity against HTLV-1 actuated ATL cells. VSV-gp160G was further noted to be highly attenuated and did not replicate efficiently in or induce significant cell death of primary CD4(+) T cells. Accordingly, VSV-gp160G did not elicit any evidence of neurotoxicity even in severely immunocompromised animals such as NOD/Shi-scid, IL-2Rγ-c-null (NSG) mice. Importantly, VSV-gp160G effectively exerted potent oncolytic activity in patient-derived ATL transplanted into NSG mice and facilitated a significant survival benefit. Our data indicate that VSV-gp160G exerts potent oncolytic efficacy against CD4(+) malignant cells and either alone or in conjunction with established therapies may provide an effective treatment in patients displaying ATL.

IMPORTANCE

Adult T cell leukemia (ATL) is a serious form of cancer with a high mortality rate. HTLV-1 infection is the etiological agent of ATL and, unfortunately, most patients succumb to the disease within a few years. Current treatment options have failed to significantly improve survival rate. In this study, we developed a recombinant strain of vesicular stomatitis virus (VSV) that specifically targets transformed CD4(+) T cells through replacement of the G protein of VSV with a hybrid fusion protein, combining domains from gp160 of HIV-1 and VSV-G. This modification eliminated the normally broad tropism of VSV and restricted infection to primarily the transformed CD4(+) cell population. This effect greatly reduced neurotoxic risk associated with VSV infection while still allowing VSV to effectively target ATL cells.

Recent advances in the treatment of adult T-cell leukemia-lymphomas

Recent advances in treatment for adult T-cell leukemia-lymphoma (ATL) are reviewed herein. It is currently possible to select a therapeutic strategy for ATL and predict prognosis by classification of patients by clinical subtypes and clinicopathological factors. Although the overall survival (OS) of patients with ATL has increased marginally because of advances in chemotherapy, further prolongation of survival might be difficult with conventional chemotherapy alone. Promising results have been reported for antiviral therapy using zidovudine and interferon-α, and, indeed, antiviral therapy is currently the standard treatment for patients with ATL in western countries. Remarkably, the 5-year OS rates are 100% for both the smoldering-type and chronic-type ATL. Recently, treatments for ATL have included allogeneic hematopoietic stem cell transplantation and molecular targeted therapies. Furthermore, the anti-CCR4 monoclonal antibody mogamulizumab has been shown to have marked cytotoxic effects on ATL cells, especially in the leukemic type of ATL. In the lymphoma type of ATL, the response rate may be improved by combining mogamulizumab with chemotherapy. It should be recognized that prevention of infection from carriers of human T-cell leukemia virus type-I and transfer of the virus from mother to infant are crucial issues for the eradication of ATL.

Clinical Features and Treatment Outcomes of 81 Patients with Aggressive Type Adult T-cell Leukemia-lymphoma at a Single Institution over a 7-year Period (2006-2012)

OBJECTIVE

Despite the remarkable advances in chemotherapy and allogeneic hematopoietic stem cell transplantation (HSCT), adult T-cell leukemia-lymphoma (ATL) is still associated with a high mortality rate. It is therefore essential to elucidate the current features of ATL.

METHODS

We retrospectively analyzed 81 patients with aggressive type ATL at our institution over a 7-year period based on Shimoyama's diagnostic criteria.

RESULTS

Eighty-one patients with a median age of 67.5 years were classified as having acute (n=47), lymphoma (n=32), or chronic type (n=2) ATL. They were initially treated by either palliative therapy (n=25) or systemic chemotherapy [n=56; cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) therapy (n=25)/vincristine, cyclophosphamide, doxorubicin, and prednisone (VCAP)-doxorubicin, ranimustine, and prednisone (AMP)-vindesine, etoposide, carboplatin, and prednisone (VECP) therapy (VCAP-AMP-VECP) or CHOP-VMMV therapy (n=31)], and showed median survival durations of 16 and 277 days, respectively. Subsequent to the initial treatment, HSCT (n=6) was performed for certain patients, thus revealing that two-thirds (n=4) relapsed, and one-third (n=2) survived for 131 days and 203 days, respectively. The relapsed ATL patients were treated with conventional salvage therapy (n=29) or anti-CC chemokine receptor 4 antibody (mogamulizumab) (n=3). The patients treated with mogamulizumab demonstrated complete response (2) and partical response (1) with short duration periods of 82 days, 83 days, and 192 days, respectively. Among the five long-term survivors (>5 years) who received chemotherapy, most showed a low and intermediate risk according to the ATL prognostic index.

CONCLUSION

In our study, the overall survival of ATL remains poor due to the advanced age of the patients at diagnosis, a high proportion of patients receiving palliative therapy, and a small proportion of long-term survivors receiving chemotherapy and undergoing HSCT. This study illustrates the current clinical features, treatment strategies, and outcomes in clinical practice.

Functional activity of monocytes and macrophages in HTLV-1 infected subjects

The Human T lymphotropic virus type-1 (HTLV-1) infects predominantly T cells, inducing proliferation and lymphocyte activation. Additionally, HTLV-1 infected subjects are more susceptible to other infections caused by other intracellular agents. Monocytes/macrophages are important cells in the defense against intracellular pathogens. Our aims were to determine the frequency of monocytes subsets, expression of co-stimulatory molecules in these cells and to evaluate microbicidal ability and cytokine and chemokine production by macrophages from HTLV-1 infected subjects. Participants were 23 HTLV-1 carriers (HC), 22 HAM/TSP patients and 22 healthy subjects (HS) not infected with HTLV-1. The frequencies of monocyte subsets and expression of co-stimulatory molecules were determined by flow cytometry. Macrophages were infected with L. braziliensis or stimulated with LPS. Microbicidal activity of macrophages was determined by optic microscopy. Cytokines/chemokines from macrophage supernatants were measured by ELISA. HAM/TSP patients showed an increase frequency of intermediate monocytes, but expression of co-stimulatory molecules was similar between the groups. Macrophages from HTLV-1 infected individuals were infected with L. braziliensis at the same ratio than macrophages from HS, and all the groups had the same ability to kill Leishmania parasites. However, macrophages from HTLV-1 infected subjects produced more CXCL9 and CCL5, and less IL-10 than cells from HS. While there was no correlation between IFN-γ and cytokine/chemokine production by macrophages, there was a correlation between proviral load and TNF and CXCL10. These data showed a dissociation between the inflammatory response and microbicidal ability of macrophages from HTLV-1 infected subjects. While macrophages ability to kill an intracellular pathogen did not differ among HTLV-1 infected subjects, these cells secreted high amount of chemokines even in unstimulated cultures. Moreover the increasing inflammatory activity of macrophages was similar in HAM/TSP patients and HC and it was related to HTLV-1 proviral load rather than the high IFN-γ production observed in these subjects.