Revised Adult T-Cell Leukemia-Lymphoma International Consensus Meeting Report

Human T-cell lymphotropic virus screening in France: Missed opportunities? A retrospective multicenter study of serological testing in hospital laboratories

Objectives

Human T-lymphotropic virus 1 infection is endemic in the French Antilles, French Guiana, and sub-Saharan Africa, the origin of many immigrants currently living in France. There are no national screening recommendations outside of the regulatory obligations concerning donations of blood, tissue, gametes, or milk to a lactarium. This study aimed to investigate the screening and diagnostic practices for this infection in France.

Methods

Serological statistics for regulatory, antenatal, sexually transmitted infections (for CeGIDDs (Centre Gratuit d'Information, de Dépistage et de Diagnostic des Infections Sexuellement Transmissibles), which are public sexual health clinics), accidental exposure to blood screenings, and diagnosis since January 1, 2018 were collected from 23 hospital laboratories (two in the French Antilles, 21 in mainland France) associated with 55 hospitals and 22 maternity units.

Results

A total absence of antenatal screening was reported by 75% of the laboratories associated with maternity units in mainland France. All the laboratories in mainland France reported an absence of screening in the accidental exposure to blood context, as did all the laboratories in mainland France associated with a CeGIDD in the context of sexually transmitted infection screening. Conversely, screening in accordance with the existing regulations was generally systematically carried out. The most frequently reported diagnostic contexts were hematology and neurology.

Conclusions

This study reveals an underscreening of human T-lymphotropic virus 1 in the hospital laboratories of mainland France.

Flow cytometric profiles with CD7 and CADM1 in CD4+ T cells are promising indicators for prognosis of aggressive ATL

ABSTRACT

Adult T-cell leukemia/lymphoma (ATL) is a poor prognosis hematological malignancy originating from human T-cell leukemia virus 1 (HTLV-1)-infected CD4+ T cells. Flow cytometric plots of CADM1 and CD7 in CD4+ T cells are useful for separating HTLV-1-uninfected T cells and ATL cells. They are indicators of clonal evolution of HTLV-1-infected cells and disease progression of asymptomatic carriers or indolent ATL. However, the impacts of the plots on the clinical course or prognosis of ATL, especially in aggressive ATL, remain unclear. We focused on the N fraction (CD4+ CADM1+ CD7-) reflecting ATL cells and analyzed the flow cytometric profiles and clinical course of 497 samples from 92 HTLV-1-infected patients who were mainly aggressive ATL. The parameters based on N fractions showed significant correlations with known indicators of ATL disease status (soluble interleukin-2 receptor, lactate dehydrogenase, abnormal lymphocytes, etc.) and sensitively reflected the treatment response of aggressive ATL. The parameters based on N fractions significantly stratified the prognosis of aggressive ATL at 4 different time points: before treatment, after 1 course of chemotherapy, at the best response after chemotherapy, and before allogeneic hematopoietic cell transplantation. Even after mogamulizumab administration, which shows potent effects for peripheral blood lesions, the N fraction was still a useful indicator for prognostic estimation. In summary, this report shows that CADM1 vs CD7 plots in CD4+ T cells are useful indicators of the clinical course and prognosis of aggressive ATL. Therefore, this CADM1 and CD7 profile is suggested to be a useful prognostic indicator consistently from HTLV-1 carriers to aggressive ATL.

Clinical Features and Survival Outcome in Aggressive-Type Adult T-Cell Leukemia/Lymphoma Patients: Real-Life Experience of a Single Center from an HTLV-1 Endemic Country

Background and Objectives: Adult T-cell leukemia/lymphoma (ATLL) is a highly aggressive T-cell lymphoproliferative disease associated with the human T-cell lymphotropic virus type I (HTLV-1). ATLL is a rare disease, found more frequently in HTLV-1-endemic areas, Romania being one of them. Despite treatment advances, the prognosis remains dismal. We aimed to describe the clinical, biological, and survival outcome features of Romanian patients with aggressive-type ATLL. Materials and Methods: We report the data of a prospective, observational, and unicentric study of all 20 patients diagnosed with lymphoma and acute types of ATLL at our center over the past 12 years. Data were collected from the patients' medical records. Results: Lymphoma-type ATLL (60%) was more common than acute-type ATLL (40%). Median age at diagnosis was 40.5 years, and most patients were female. Laboratory data revealed significant differences between acute and lymphoma-type ATLL, namely, higher leukocyte (p = 0.02) and lymphocyte counts (p = 0.02) and higher levels of corrected calcium (p = 0.001) in acute-type ATLL. All patients received chemotherapy, and only two underwent allogeneic stem cell transplantation. Only six patients obtained a complete or partial response to chemotherapy, mostly the lymphoma-type ones. The median survival for all patients was 6.37 months, with higher survival in the lymphoma-type ATLL (8.16 months) than in the acute-type (3.60 months). Normal calcium levels (p = 0.011), uric acid (p = 0.005), BUN score (p = 0.000), JCOG-PI moderate risk (p = 0.038), and obtaining complete or partial response (p = 0.037) were associated with higher survival. Conclusion: Aggressive-type ATLL among Romanian patients presents distinct characteristics, including younger age at diagnosis, female predominance, and higher incidence of lymphoma-type ATLL compared to currently reported data. Survival remains very low, with all subtypes experiencing a median survival of less than one year.

Clinical characteristics, genetic alterations, and prognosis of adult T-cell leukemia/lymphoma: an 11-year multicenter retrospective study in China

Adult T-cell leukemia/lymphoma (ATLL) is an aggressive malignancy with a poor prognosis, and there is little data available from the Chinese population. This retrospective study included 115 patients diagnosed with ATLL who were treated across five hospitals in China from June 2011 to December 2022. The median age at diagnosis was 53 years. Several genes involved in T-cell receptor-induced nuclear factor κB (TCR-NF-κB) signaling were commonly mutated, including PLCG1, CIC, PRKCB, CARD11, and IRF4. Eighty-seven patients received chemotherapy. Of these, 13 received a hematopoietic stem cell transplant (HSCT) (allogeneic-HSCT, n=9; autologous-HSCT, n=4) after chemotherapy. Following initial multiagent chemotherapy using EPOCH/CHOEP and other regimens, the overall response rates were 80.6% (complete response [CR], 44.4%) and 42.8% (CR, 14.2%), respectively. The 4-year survival rates (median survival time in days) for EPOCH/CHOEP (n=43), HSCT (n=13), and CHOP-based regimens (n=31) were 12.7% (138), 30.8% (333), and 0% (66), respectively. Lymphadenopathy, EPOCH/CHOEP, and hematopoietic stem cell transplantation were independent prognostic protective factors in patients with aggressive ATLL. Chinese patients exhibit a higher incidence of aggressive-type ATLL, sharing similar genetic alterations with Japanese patients. Etoposide-based chemotherapy (EPOCH or CHOEP) remains the preferred choice for aggressive ATLL, and upfront allogeneic HSCT should be considered in all eligible patients.

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.

Mechanisms of action and resistance in histone methylation-targeted therapy

Epigenomes enable the rectification of disordered cancer gene expression, thereby providing new targets for pharmacological interventions. The clinical utility of targeting histone H3 lysine trimethylation (H3K27me3) as an epigenetic hallmark has been demonstrated1-7. However, in actual therapeutic settings, the mechanism by which H3K27me3-targeting therapies exert their effects and the response of tumour cells remain unclear. Here we show the potency and mechanisms of action and resistance of the EZH1-EZH2 dual inhibitor valemetostat in clinical trials of patients with adult T cell leukaemia/lymphoma. Administration of valemetostat reduced tumour size and demonstrated durable clinical response in aggressive lymphomas with multiple genetic mutations. Integrative single-cell analyses showed that valemetostat abolishes the highly condensed chromatin structure formed by the plastic H3K27me3 and neutralizes multiple gene loci, including tumour suppressor genes. Nevertheless, subsequent long-term treatment encounters the emergence of resistant clones with reconstructed aggregate chromatin that closely resemble the pre-dose state. Acquired mutations at the PRC2-compound interface result in the propagation of clones with increased H3K27me3 expression. In patients free of PRC2 mutations, TET2 mutation or elevated DNMT3A expression causes similar chromatin recondensation through de novo DNA methylation in the H3K27me3-associated regions. We identified subpopulations with distinct metabolic and gene translation characteristics implicated in primary susceptibility until the acquisition of the heritable (epi)mutations. Targeting epigenetic drivers and chromatin homeostasis may provide opportunities for further sustained epigenetic cancer therapies.

Clinicopathological definition, management and prognostic value of mogamulizumab-associated rash and other cutaneous events: A systematic review

Mogamulizumab is a first-in-class IgG1k monoclonal antibody that selectively targets the chemokine receptor type 4. The drug has received Food and Drug administration authorisation for mycosis fungoides and Sézary syndrome following failure of at least one previous course of systemic therapy and now is available in Europe. One of the most common treatment-related side effects observed has been the mogamulizumab-associated rash (MAR), which affects up to a quarter of patients and is the most frequent adverse event leading to drug discontinuation. The aim of this study is to perform a systematic review of the literature on patients diagnosed with MAR and other mogamulizumab-related cutaneous events to describe the clinical and histological characteristics, the management in clinical practice and to assess whether these events have prognostic implications. In total, 2073 records were initially identified through a literature search, 843 of which were duplicates. After screening for eligibility and inclusion criteria, 49 articles reporting mogamulizumab-associated cutaneous events were included. Totally, 1516 patients were retrieved, with a slight male prevalence as for the available data (639 males and 570 females, i.e. 52.9% vs. 47.1%). Regarding the reported clinicopathological findings of the cutaneous reactions, the five most common patterns were spongiotic/psoriasiform dermatitis (22%), eruptions characterized by the presence of papules and/or plaques (16.1%), cutaneous granulomatosis (11.4%), morbilliform or erythrodermic dermatitis (9.4%) and photodermatitis (7.1%). Our results highlight how the majority of the reported cutaneous adverse events on mogamulizumab are of mild-to-moderate entity and generally manageable in clinical practice, though prompt recognition is essential and case-by-case assessment should be recommended. Future research will need to focus on the MAR prognostic implications and to identify genomic and molecular markers for a more rapid and accurate diagnosis.

Central Nervous System Relapse in T and NK cell Lymphomas

PURPOSE OF REVIEW

T and NK cell lymphomas are relatively rare and heterogeneous forms of non-Hodgkin lymphoma that are associated with high rates of mortality. Central nervous system relapse carries significant morbidity, though management is largely extrapolated from literature in B cell neoplasms. As such, outcomes for central nervous system involvement in T/NK cell lymphomas are dismal with no standard of care. In this review, we discuss the epidemiology of central nervous system relapse in T/NK cell lymphomas and critically analyze available literature regarding prophylaxis and treatment.

RECENT FINDINGS

Retrospective studies of central nervous system involvement in T/NK cell lymphomas have been limited by small sample sizes and heterogeneity of subtypes, though sites of extranodal involvement and disease subtypes are consistently reported as risk factors. Compelling evidence for the use of central nervous system-directed prophylactic therapy has not yet been established, though recent reports of central nervous system activity with novel agents may suggest promising therapeutic options. The overall rarity of T and NK cell lymphomas has precluded adequate study of prophylaxis and treatment of central nervous system relapse. Collaborative efforts are needed to better define strategies to address CNS disease in T/NK cell lymphomas. These should involve the use of targeted agents, which may hold an advantage over traditional cytotoxic drugs.

New Perspectives about Drug Candidates Targeting HTLV-1 and Related Diseases

Among the human T-lymphotropic virus (HTLV) types, HTLV-1 is the most prevalent, and it has been linked to a spectrum of diseases, including HAM/TSP, ATLL, and hyperinfection syndrome or disseminated strongyloidiasis. There is currently no globally standard first-line treatment for HTLV-1 infection and its related diseases. To address this, a comprehensive review was conducted, analyzing 30 recent papers from databases PubMed, CAPES journals, and the Virtual Health Library (VHL). The studies encompassed a wide range of therapeutic approaches, including antiretrovirals, immunomodulators, antineoplastics, amino acids, antiparasitics, and even natural products and plant extracts. Notably, the category with the highest number of articles was related to drugs for the treatment of ATLL. Studies employing mogamulizumab as a new perspective for ATLL received greater attention in the last 5 years, demonstrating efficacy, safe use in the elderly, significant antitumor activity, and increased survival time for refractory patients. Concerning HAM/TSP, despite corticosteroid being recommended, a more randomized clinical trial is needed to support treatment other than corticoids. The study also included a comprehensive review of the drugs used to treat disseminated strongyloidiasis in co-infection with HTLV-1, including their administration form, in order to emphasize gaps and facilitate the development of other studies aiming at better-directed methodologies. Additionally, docking molecules and computer simulations show promise in identifying novel therapeutic targets and repurposing existing drugs. These advances are crucial in developing more effective and targeted treatments against HTLV-1 and its related diseases.

Adult T-cell leukemia/lymphoma in HTLV-1 non-endemic regions

BACKGROUND

HTLV-1 infection is a neglected disease, despite producing neurological and lymphoproliferative severe illnesses and affect over 10 million people worldwide. Roughly 5% of HTLV-1 carriers develop Adult T-cell leukemia/lymphoma (ATLL), one of the most aggressive hematological malignancies.

METHODS

A national HTLV-1 register exists since 1989 in Spain, a non-endemic country with a large migrant flow from Latin America and Equatorial Africa, where HTLV-1 is endemic. The main features of all patients diagnosed with ATLL in Spain up to date are reported.

RESULTS

A total of 451 cases of HTLV-1 infection had been reported in Spain until the end of year 2022. ATLL had been diagnosed in 35 (7.8%). The current average incidence of ATLL in Spain is of two cases per year. Women represent 57% of ATLL patients. Mean age at diagnosis was 47 years-old. Roughly 57% were Latin Americans and 26% Africans. At diagnosis, the majority presented with acute or lymphoma clinical forms. Survival was shorter than one year in most of them. Mean HTLV-1 proviral load was significantly greater in ATLL patients than in asymptomatic HTLV-1 carriers (2,305 vs 104 copies/104 PBMC). HTLV-1 subtyping in 6 ATLL patients found the 1a transcontinental variant (n = 4) and the Japanese variant (n = 2). All ATLL patients were negative for HIV-1, did not develop HTLV-1-associated myelopathy and were not transplant recipients.

CONCLUSION

The rate of ATLL is very low in Spain and mostly associated to migrants from HTLV-1 endemic regions. Given the poor clinical outcome of ATLL, HTLV-1 testing should be performed at least once in all migrants coming from HTLV-1 endemic countries and in natives who have lived in or had sex partners from such regions.

Human T-Cell Leukemia Virus Type 1 Oncogenesis between Active Expression and Latency: A Possible Source for the Development of Therapeutic Targets

The human T-cell leukemia virus type 1 (HTLV-1) is the only known human oncogenic retrovirus. HTLV-1 can cause a type of cancer called adult T-cell leukemia/lymphoma (ATL). The virus is transmitted through the body fluids of infected individuals, primarily breast milk, blood, and semen. At least 5-10 million people in the world are infected with HTLV-1. In addition to ATL, HTLV-1 infection can also cause HTLV-I-associated myelopathy (HAM/TSP). ATL is characterized by a low viral expression and poor prognosis. The oncogenic mechanism triggered by HTLV-1 is extremely complex and the molecular pathways are not fully understood. However, viral regulatory proteins Tax and HTLV-1 bZIP factor (HBZ) have been shown to play key roles in the transformation of HTLV-1-infected T cells. Moreover, several studies have shown that the final fate of HTLV-1-infected transformed Tcell clones is the result of a complex interplay of HTLV-1 oncogenic protein expression with cellular transcription factors that subvert the cell cycle and disrupt regulated cell death, thereby exerting their transforming effects. This review provides updated information on the mechanisms underlying the transforming action of HTLV-1 and highlights potential therapeutic targets to combat ATL.

Oncoviruses: How do they hijack their host and current treatment regimes

Viruses have the ability to modulate the cellular machinery of their host to ensure their survival. While humans encounter numerous viruses daily, only a select few can lead to disease progression. Some of these viruses can amplify cancer-related traits, particularly when coupled with factors like immunosuppression and co-carcinogens. The global burden of cancer development resulting from viral infections is approximately 12%, and it arises as an unfortunate consequence of persistent infections that cause chronic inflammation, genomic instability from viral genome integration, and dysregulation of tumor suppressor genes and host oncogenes involved in normal cell growth. This review provides an in-depth discussion of oncoviruses and their strategies for hijacking the host's cellular machinery to induce cancer. It delves into how viral oncogenes drive tumorigenesis by targeting key cell signaling pathways. Additionally, the review discusses current therapeutic approaches that have been approved or are undergoing clinical trials to combat malignancies induced by oncoviruses. Understanding the intricate interactions between viruses and host cells can lead to the development of more effective treatments for virus-induced cancers.

Impact of HLA-mismatched unrelated transplantation in patients with adult T-cell leukemia/lymphoma

This Japanese nationwide retrospective study investigated the impact of HLA-mismatched unrelated transplantation for adult T-cell leukemia-lymphoma (ATL) patients who received transplantation between 2000 and 2018. We compared 6/6 antigen-matched related donor (MRD), 8/8 allele-matched unrelated donor (8/8MUD), and 1 allele-mismatched unrelated donor (7/8MMUD) in the graft-versus-host direction. We included 1191 patients; 449 (37.7%) were in the MRD group, 466 (39.1%) in the 8/8MUD group, and 276 (23.7%) in the 7/8MMUD group. In the 7/8MMUD group, 97.5% of patients received bone marrow transplantation, and no patients received post-transplant cyclophosphamide. The cumulative incidences of non-relapse mortality (NRM) and relapse at 4 years, and the probabilities of overall survival at 4 years in the MRD group were 24.7%, 44.4%, 37.5%, in the 8/8MUD group were 27.2%, 38.2%, and 37.9%, and in the 7/8MMUD group were 34.0%, 34.4%, and 35.3%, respectively. The 7/8MMUD group had a higher risk of NRM (hazard ratio (HR) 1.50 [95% CI, 1.13-1.98; P = 0.005]) and a lower risk of relapse (HR 0.68 [95% CI, 0.53-0.87; P = 0.003]) than the MRD group. The donor type was not a significant risk factor for overall mortality. These data suggest that 7/8MMUD is an acceptable alternative donor when an HLA-matched donor is unavailable.

HTLV-1 cell-free DNA in plasma as a potential biomarker in HTLV-1 carriers and adult T-cell leukemia-lymphoma

Viral cell-free DNA (cfDNA) in plasma has been widely evaluated for detecting cancer and monitoring disease in virus-associated tumors. We investigated whether the amount of cfDNA of human T-cell leukemia virus type 1 (HTLV-1) correlates with disease state in adult T-cell leukemia-lymphoma (ATL). HTLV-1 cfDNA in aggressive ATL was significantly higher than that in indolent ATL and asymptomatic carriers. Notably, patients with lymphoma type represented higher HTLV-1 cfDNA amount than chronic and smoldering subtypes, though they had no abnormal lymphocytes in the peripheral blood. HTLV-1 cfDNA can be a universal biomarker that reflects the expansion of ATL clones.

Lenalidomide treatment for recurrent adult T-cell leukemia/lymphoma after allogeneic hematopoietic cell transplantation

Patients with recurrent adult T-cell leukemia/lymphoma (ATL) after allogeneic hematopoietic cell transplantation (allo-HCT) have a dismal prognosis. We retrospectively evaluated the safety and efficacy of lenalidomide (LEN) in 11 consecutive patients with recurrent ATL after allo-HCT. The median time from allo-HCT to ATL recurrence was 111 days (range, 20-1476), and that from allo-HCT to the initiation of LEN was 162 days (range, 43-1560). The median initial daily dose of LEN was 10 mg (range, 5-25), and the median duration of LEN treatment was 37 days (range, 3-1078). Three patients (27%) achieved complete response and two (18%) achieved partial response (PR). The rates of complete or PR according to the involved site were 57% for skin and 50% for nodal or extranodal lesions. With a median follow-up of 1033 days (range, 601-1465) among survivors, the 1-year probability of overall survival (OS) after ATL recurrence was 55%. Grade ≥3 toxicities included cytopenia (n = 4), superficial vein thrombosis (n = 1), and deep vein thrombosis (n = 1). Graft-versus-host disease (GVHD) newly developed in five patients (45%) and worsened in four patients (36%). The median duration from the initiation of LEN to GVHD onset or worsening was 5 days (range, 1-9). GVHD was manageable in all patients. Seven patients received mogamulizumab (MOG) for recurrent ATL before LEN treatment. The overall response rates to LEN were 57% in patients who had previously received MOG and 25% in those who had not. The 1-year probabilities of OS after recurrent ATL were 71% in patients who had previously received MOG and 25% in those who had not. Although cytopenia and GVHD are common among patients with recurrent ATL after allo-HCT, LEN may improve survival. Administering MOG before LEN may augment treatment efficacy in the allo-HCT population.

Therapeutic efficacy of the resorcylic acid lactone LL-Z1640-2 for adult T-cell leukaemia/lymphoma

Adult T-cell leukaemia/lymphoma (ATL) remains incurable. The NF-κB and interferon regulatory factor 4 (IRF4) signalling pathways are among the critical survival pathways for the progression of ATL. TGF-β-activated kinase 1 (TAK1), an IκB kinase-activating kinase, triggers the activation of NF-κB. The resorcylic acid lactone LL-Z1640-2 is a potent irreversible inhibitor of TAK1/extracellular signal-regulated kinase 2 (ERK2). We herein examined the therapeutic efficacy of LL-Z1640-2 against ATL. LL-Z1640-2 effectively suppressed the in vivo growth of ATL cells. It induced in vitro apoptosis and inhibited the nuclear translocation of p65/RelA in ATL cells. The knockdown of IRF4 strongly induced ATL cell death while downregulating MYC. LL-Z1640-2 as well as the NF-κB inhibitor BAY11-7082 decreased the expression of IRF4 and MYC at the protein and mRNA levels, indicating the suppression of the NF-κB-IRF4-MYC axis. The treatment with LL-Z1640-2 also mitigated the phosphorylation of p38 MAPK along with the expression of CC chemokine receptor 4. Furthermore, the inhibition of STAT3/5 potentiated the cytotoxic activity of LL-Z1640-2 against IL-2-responsive ATL cells in the presence of IL-2. Therefore, LL-Z1640-2 appears to be an effective treatment for ATL. Further studies are needed to develop more potent compounds that retain the active motifs of LL-Z1640-2.

Treatment of Adult T-Cell Leukemia/Lymphoma: Established Paradigms and Emerging Directions

OPINION STATEMENT

Adult T-cell leukemia/lymphoma (ATL) is a rare, aggressive subtype of peripheral T-cell lymphoma developing after many years of chronic, asymptomatic infection with the retrovirus human T-cell lymphotropic virus type 1 (HTLV-1). HTLV-1 is endemic to certain geographic areas of the world, and primary infection generally occurs in infancy through mother-to-child transmission via breastfeeding. In less than 5% of infected individuals, a decades-long pathogenic process culminates in the development of ATL. Aggressive subtypes of ATL are life-threatening and challenging to treat, with median overall survival typically less than 1 year in the absence of allogeneic hematopoietic cell transplantation (alloHCT). Owing to the rarity of this illness, prospective large-scale clinical trials have been challenging to perform, and treatment recommendations are largely founded upon limited evidence. Herein, we review the current therapeutic options for ATL, providing a broad literature overview of the foremost clinical trials and reports of this disease. We emphasize our own treatment paradigm, which is broadly based upon disease subtype, patient fitness, and intent to perform alloHCT. Finally, we highlight recent advances in understanding ATL disease biology and important ongoing clinical trials that we foresee as informative and potentially practice-changing.

Prospects of early therapeutic interventions for indolent adult T-cell leukemia/lymphoma based on the chronic lymphocytic leukemia progression model

Adult T-cell leukemia/lymphoma (ATLL) has aggressive clinical behaviors, and improving its prognosis is a great challenge. A disease progression model from asymptomatic human T-cell leukemia virus type 1 carrier to aggressive-type ATLL has been proposed, and indolent ATLL comprising a smoldering or favorable chronic type is located at the midpoint. Even the most favorable smoldering type has a 4-year overall survival rate of <60%. Although watchful waiting is pervasive in patients with indolent ATLL, early therapeutic intervention is discussed among hematologists. Indolent ATLL was once termed T-cell-derived chronic lymphocytic leukemia (CLL). Unlike indolent ATLL, several molecular-targeted agents at the initial treatment have dramatically improved CLL prognosis. Recent studies on CLL have revealed a similar progression model involving premalignant monoclonal B-cell lymphocytosis (MBL). In particular, individuals with high-count MBL have an increased lymphoma risk. Considering the unsatisfactory long-term prognosis of indolent ATLL, further treatment strategies, including precision medicine, are warranted.

Integrated molecular and immunological features of human T-lymphotropic virus type 1 infection and disease progression to adult T-cell leukaemia or lymphoma

The human T-lymphotropic virus type 1 (HTLV-1) retrovirus infects 10-20 million people globally, with endemic regions in southwestern Japan, the Caribbean basin, Africa, and central Australia. HTLV-1 is associated with lifelong infection and immune suppression, resulting in a range of serious sequalae, including adult T-cell leukaemia or lymphoma (ATLL) in 5% of cases. To date, there are no preventive or curative treatments for HTLV-1 and treatment outcomes for ATLL remain generally poor. Depending on the disease subtype, overall survival is 8-55 months. Recent advancements in the past decade have identified genetic, molecular, and immunological events occurring throughout the lives of individuals infected with HTLV-1 and of those who progress to ATLL. In addition, updated guidelines for clinical management have been published. With the aim of focusing research efforts on the development of treatments for both HTLV-1 infections and ATLL, we have conceptualised a four-step disease model for HTLV-1-associated ATLL: (1) viral exposure, (2) establishment of chronic infection, (3) cellular transformation and evolution, and (4) disease presentation and management. For each stage we describe the clinical features, molecular and immunological factors involved, potential biomarkers of disease progression, and the therapeutic applicability of individual targets. We also discuss emerging concepts and novel treatment approaches. Our hope is that this model will promote research interest and guide the testing of new treatments for this neglected virus and its associated rare cancer.

HTLV-1 persistence and the oncogenesis of adult T-cell leukemia/lymphoma

Human T-cell leukemia virus type 1 (HTLV-1), also known as human T-lymphotropic virus type 1, causes the aggressive malignancy known as adult T-cell leukemia/lymphoma (ATL) in 5% of infected people and a chronic progressive inflammatory disease of the central nervous system, HTLV-1-associated myelopathy, in ∼0.3% to 4% of them, varying between regions where it is endemic. Reliable treatments are lacking for both conditions, although there have been promising recent advances in the prevention and treatment of ATL. Because ATL typically develops after several decades of infection, it is necessary to understand how the virus persists in the host despite a strong immune response, and how this persistence results in oncogenesis.

Adult T-cell leukemia and lymphoma in French Guiana: a retrospective analysis with real-life data from 2009 to 2019

Background

Adult T-cell leukemia/lymphoma (ATL), one of the most aggressive cancers in the world, occurs in 5% of the 10 million people living with HTLV-1 worldwide. French Guiana, a French overseas territory in South America, is one of the highest endemic areas of HTLV-1 worldwide. Here, we describe the demographic and clinical characteristics and outcome of ATL in this area.

Methods

We retrospectively collected data from all patients diagnosed between 2009 and 2019. Patients were distributed according to Shimoyama's classification. Prognostic factors were explored through univariate analysis.

Findings

Over the 10-year study period, 41 patients with a median age of 54 years at diagnosis were identified, among whom 56% were women. Sixteen (39%) patients were Maroons, a cultural group descendant of the runaway enslaved Africans from former Dutch Guiana. Among the study population, 23 (56%) had an acute type, 14 (34%) a lymphoma type, and one and one chronic and primary cutaneous tumour, respectively. First-lines of treatment included either chemotherapy or Zidovudine combined with pegylated interferon alpha. The 4-year overall survival was 11.4% for the entire population with 0% and 11% for lymphoma and acute forms, respectively. The median progression-free survival was 93 and 115 days for the acute and lymphoma groups (p = 0.37), respectively. Among the twenty-nine patients who died, 8 (28%) died of toxicity, 7 (24%) died of disease progression and the cause of death remained unknown in 14 (48%) patients. Due to the overall poor prognosis, no significant prognostic factors could be identified.

Interpretation

This study provides real-life data from ATL patients in French Guiana, a remote territory in a middle-income region. Patients, mostly Maroons, presented with a younger age and the prognosis was worse than expected compared to Japanese patients.

Funding

None.

An update on viral-induced cutaneous lymphoproliferative disorders. CME Part I

Viral-induced cutaneous T-cell lymphomas are an uncommon group of lymphoproliferative disorders characterized by a viral infection of T and natural killer (NK) cells. This group of cutaneous T-cell lymphomas is more commonly encountered in Asians and Native Americans from Central and South America compared with Western populations. Viral-associated lymphoproliferative disorders include a spectrum of entities that range from nonneoplastic lesions, such as chronic active Epstein-Barr virus infection and infective dermatitis to malignant diseases, such as extranodal NK/T-cell lymphoma, hydroa vacciniforme-like T-cell lymphoma, and adult T-cell leukemia/lymphoma. This review article will focus on hydroa vacciniforme-like lymphoproliferative disorder, extranodal NK/T-cell lymphoma, adult T-cell leukemia/lymphoma, lymphomatoid granulomatosis, and Epstein-Barr virus-positive mucocutaneous ulcers. We will review the pathogenesis of these conditions and the challenges of making a timely diagnosis in early-stage disease and discuss the common clinicopathologic manifestations, mutational landscape, and approaches to treat these highly aggressive and frequently lethal types of lymphoma.

Shikonin Induces ROS-Dependent Apoptosis Via Mitochondria Depolarization and ER Stress in Adult T Cell Leukemia/Lymphoma

Adult T cell leukemia/lymphoma (ATLL) is an aggressive T-cell malignancy that develops in some elderly human T-cell leukemia virus (HTVL-1) carriers. ATLL has a poor prognosis despite conventional and targeted therapies, and a new safe and efficient therapy is required. Here, we examined the anti-ATLL effect of Shikonin (SHK), a naphthoquinone derivative that has shown several anti-cancer activities. SHK induced apoptosis of ATLL cells accompanied by generation of reactive oxygen species (ROS), loss of mitochondrial membrane potential, and induction of endoplasmic reticulum (ER) stress. Treatment with a ROS scavenger, N-acetylcysteine (NAC), blocked both loss of mitochondrial membrane potential and ER stress, and prevented apoptosis of ATLL cells, indicating that ROS is an upstream trigger of SHK-induced apoptosis of ATLL cells through disruption of the mitochondrial membrane potential and ER stress. In an ATLL xenografted mouse model, SHK treatment suppressed tumor growth without significant adverse effects. These results suggest that SHK could be a potent anti-reagent against ATLL.

An open-label, single-arm phase 2 trial of valemetostat for relapsed or refractory adult T-cell leukemia/lymphoma

Adult T-cell leukemia/lymphoma (ATL) is an aggressive non-Hodgkin lymphoma with poor prognosis and few treatment options for patients with relapsed, recurrent, or refractory disease. We evaluated the efficacy and safety of valemetostat, a potent enhancer of zeste homolog 2 (EZH2) and EZH1 inhibitor, in treating relapsed or refractory (R/R) ATL. This multicenter phase 2 trial enrolled patients with R/R aggressive ATL (acute, lymphoma, unfavorable chronic type). Patients received valemetostat 200 mg/day orally until progressive disease or unacceptable toxicity. The primary end point was overall response rate (ORR) centrally assessed by an independent efficacy assessment committee (IEAC). Secondary end points included best response in disease compartments, duration of response (DOR), pharmacokinetics, and safety. Twenty-five patients (median age, 69.0 years) with a median of 3 prior lines of therapy were enrolled; 24 had prior mogamulizumab treatment. The primary end point was met with a centrally reviewed ORR of 48.0% (90% confidence interval [CI], 30.5-65.9), including 5 complete and 7 partial remissions. Patients pretreated with mogamulizumab had an ORR of 45.8% (4 complete and 7 partial remissions). IEAC-assessed median DOR was not reached (NR) (95% CI, 1.87 to NR; months). Treatment-emergent adverse events (TEAEs) were manageable. TEAEs that occurred in ≥20% of patients included thrombocytopenia, anemia, alopecia, dysgeusia, neutropenia, lymphopenia, leukopenia, decreased appetite, and pyrexia. Grade ≥3 TEAEs included thrombocytopenia, anemia, lymphopenia, leukopenia, and neutropenia. Valemetostat demonstrated promising efficacy and tolerability in heavily pretreated patients, warranting further investigation in treating R/R ATL. This trial was registered at www.clinicaltrials.gov as #NCT04102150.

Malignancy and viral infections in Sub-Saharan Africa: A review

The burden of malignancy related to viral infection is increasing in Sub-Saharan Africa (SSA). In 2018, approximately 2 million new cancer cases worldwide were attributable to infection. Prevention or treatment of these infections could reduce cancer cases by 23% in less developed regions and about 7% in developed regions. Contemporaneous increases in longevity and changes in lifestyle have contributed to the cancer burden in SSA. African hospitals are reporting more cases of cancer related to infection (e.g., cervical cancer in women and stomach and liver cancer in men). SSA populations also have elevated underlying prevalence of viral infections compared to other regions. Of 10 infectious agents identified as carcinogenic by the International Agency for Research on Cancer, six are viruses: hepatitis B and C viruses (HBV and HCV, respectively), Epstein-Barr virus (EBV), high-risk types of human papillomavirus (HPV), Human T-cell lymphotropic virus type 1 (HTLV-1), and Kaposi's sarcoma herpesvirus (KSHV, also known as human herpesvirus type 8, HHV-8). Human immunodeficiency virus type 1 (HIV) also facilitates oncogenesis. EBV is associated with lymphomas and nasopharyngeal carcinoma; HBV and HCV are associated with hepatocellular carcinoma; KSHV causes Kaposi's sarcoma; HTLV-1 causes T-cell leukemia and lymphoma; HPV causes carcinoma of the oropharynx and anogenital squamous cell cancer. HIV-1, for which SSA has the greatest global burden, has been linked to increasing risk of malignancy through immunologic dysregulation and clonal hematopoiesis. Public health approaches to prevent infection, such as vaccination, safer injection techniques, screening of blood products, antimicrobial treatments and safer sexual practices could reduce the burden of cancer in Africa. In SSA, inequalities in access to cancer screening and treatment are exacerbated by the perception of cancer as taboo. National level cancer registries, new screening strategies for detection of viral infection and public health messaging should be prioritized in SSA's battle against malignancy. In this review, we discuss the impact of carcinogenic viruses in SSA with a focus on regional epidemiology.

Current and emerging therapeutic strategies in adult T-cell leukemia-lymphoma

Adult T-cell leukemia-lymphoma (ATL) is classified into four clinical subtypes: acute, lymphoma, chronic, and smoldering. Chronic ATL is further divided into unfavorable and favorable chronic types according to serum lactate dehydrogenase, blood urea nitrogen, and serum albumin values. Acute, lymphoma, and unfavorable chronic types are categorized as aggressive ATL, whereas favorable chronic and smoldering types are categorized as indolent ATL. Intensive chemotherapy alone is not sufficient to prevent relapse of aggressive ATL. Allogeneic hematopoietic stem cell transplantation is a potential therapeutic option to cure aggressive ATL in younger patients. Reduced-intensity conditioning regimens have decreased transplantation-related mortality, and increased donor availability has dramatically improved transplant access. New agents, including mogamulizumab, brentuximab vedotin, tucidinostat, and valemetostat, have recently become available for patients with aggressive ATL in Japan. Here, I provide an overview of recent advances in therapeutic strategies for ATL.

Successful Treatment of an Aggressive Adult T-cell Leukemia/Lymphoma with Strong CD30 Expression Using Brentuximab Vedotin as Combination and Maintenance Therapy

Adult T-cell leukemia/lymphoma (ATL) is a highly aggressive malignant tumor associated with a poor prognosis. We herein report a 63-year-old man who was newly diagnosed with aggressive ATL. He was treated with brentuximab vedotin (BV) plus cyclophosphamide, doxorubicin, and prednisone (A+CHP therapy), along with intrathecal chemotherapy using methotrexate and cytarabine. After achieving remission, he was placed on maintenance therapy with BV in the outpatient setting every 21 days for 17 months, without relapse. We suggest that initial treatment with A+CHP therapy and BV maintenance therapy may be beneficial against strongly CD30-expressing ATL.

Central Nervous System Progression/Relapse in Mature T- and NK-Cell Lymphomas

Non-Hodgkin lymphomas (NHL) are cancers of mature B-, T-, and NK-cells which display marked biological heterogeneity between different subtypes. Mature T- and NK-cell neoplasms are an often-aggressive subgroup of NHL and make up approximately 15% of all NHL. Long-term follow up studies have demonstrated that patients with relapsed/refractory disease have dismal outcomes; in particular, secondary central nervous system (CNS) involvement is associated with higher mortality, though it remains controversial whether this independently confers worse outcomes or if it simply reflects more aggressive systemic disease. Possible risk factors predictive of CNS involvement, such as an elevated lactate dehydrogenase and more than two sites of extranodal involvement, may suggest the latter, though several studies have suggested that discrete sites of anatomic involvement or tumor histology may be independent risk factors as well. Ultimately, small retrospective case series form the basis of our understanding of this rare but devastating event but have not yet demonstrated a consistent benefit of CNS-directed prophylaxis in preventing this outcome. Nonetheless, ongoing efforts are working to establish the epidemiology of CNS progression/relapse in mature T- and NK-cell lymphomas with the goal of identifying clinicopathologic risk factors, which may potentially help discern which patients may benefit from CNS-directed prophylactic therapy or more aggressive systemic therapy.

Validation of the iATL-PI prognostic index in therapeutic decision-making for patients with smoldering and chronic ATL: a multicenter study

Adult T cell leukemia-lymphoma (ATL) is clinically heterogeneous and is classified into four subtypes: acute, lymphoma, chronic, and smoldering. Recently, a new prognostic index based on the value of soluble interleukin-2 receptor, denoted the "iATL-PI," has been proposed for patients with smoldering and chronic ATL. To evaluate the effectiveness of the iATL-PI, we re-analyzed our previously published data on 176 patients with smoldering or chronic ATL (76 smoldering, 100 chronic) diagnosed between 2010 and 2011, as well data from the subsequent follow-up study on prognosis between 2016 and 2017. The proportions for the low-, intermediate-, and high-risk iATL-PI groups at the time of ATL diagnosis were 44.7%, 48.7%, and 5% for smoldering ATL; 6.3%, 71.9%, and 21.9% for favorable chronic ATL; and 5.9%, 27.9%, and 66.2% for unfavorable chronic ATL, respectively. The survival of patients with smoldering or chronic ATL as a whole was significantly stratified according to the three iATL-PI groups. Most patients with unfavorable chronic ATL in the low iATL-PI risk group had indolent clinical courses. Our results showed that iATL may become a useful tool to predict the prognosis of smoldering and chronic ATL, which have diverse clinical courses.

A frequent PLCγ1 mutation in adult T-cell leukemia/lymphoma determines functional properties of the malignant cells

BACKGROUND

Development of adult T-cell leukemia/lymphoma (ATL) involves human T-cell leukemia virus type 1 (HTLV-1) infection and accumulation of somatic mutations. The most frequently mutated gene in ATL (36 % of cases) is phospholipase C gamma1 (PLCG1). PLCG1 is also frequently mutated in other T-cell lymphomas. However, the functional consequences of the PLCG1 mutations in cancer cells have not been characterized.

METHODS

We compared the activity of the wild-type PLCγ1 with that of a mutant carrying a hot-spot mutation of PLCγ1 (S345F) observed in ATL, both in cells and in cell-free assays. To analyse the impact of the mutation on cellular properties, we quantified cellular proliferation, aggregation, chemotaxis and apoptosis by live cell-imaging in an S345F+ ATL-derived cell line (KK1) and a KK1 cell line in which we reverted the mutation to the wild-type sequence using CRISPR/Cas9 and homology-directed repair.

FINDINGS

The PLCγ1 S345F mutation results in an increase of basal PLC activity in vitro and in different cell types. This higher basal activity is further enhanced by upstream signalling. Reversion of the S345F mutation in the KK1 cell line resulted in reduction of the PLC activity, lower rates of proliferation and aggregation, and a marked reduction in chemotaxis towards CCL22. The PLCγ1-pathway inhibitors ibrutinib and ritonavir reduced both the PLC activity and the tested functions of KK1 cells.

INTERPRETATION

Consistent with observations from clinical studies, our data provide direct evidence that activated variants of the PLCγ1 enzyme contribute to the properties of the malignant T-cell clone in ATL.

FUNDING

MRC (UK) Project Grant (P028160).

Advances in the treatment of HTLV-1-associated adult T-cell leukemia lymphoma

Adult T-cell leukemia/lymphoma (ATLL) is an aggressive hematologic malignancy linked to HTLV-1 infection, which is refractory to therapy. The precise mechanism of oncogenesis in ATLL is incompletely understood, however, oncogenic viral genes Tax and Hbz are implicated, and recent large genomic and transcriptome studies provide further insight. Despite progress in understanding the disease, survival and outcome with current therapies remain poor. Long-term survivors are reported, primarily among those with indolent disease or activating CC chemokine receptor 4 mutations, however, allogeneic hematopoietic stem cell transplant is the only curative treatment option. The majority of patients succumb to their disease and ongoing and collaborative research efforts are needed. I will review recent updates in HTLV-1-associated ATLL epidemiology, pathogenesis, therapy, and prevention.

The clinical impact of the ratio of C-reactive protein to albumin (CAR) in patients with acute- and lymphoma-type adult T-cell leukemia-lymphoma (ATL)

Recently, the ratio of C-reactive protein to albumin (CAR) is used as an inflammatory marker that has been demonstrated to be a simple and reliable prognostic factor in solid tumors and hematological malignancy. However, no studies of the CAR have been performed in patients with adult T-cell leukemia-lymphoma (ATL). We retrospectively analyzed the clinical features and outcomes in 68 newly diagnosed acute- and lymphoma-type ATL [(acute-(n=42) or lymphoma-type (n=26)] patients in Miyazaki Prefecture from 2013 to 2017. Furthermore, we investigated correlations between pretreatment CAR levels and clinical features. The median age was 67 years (range, 44 - 87). Patients were initially treated by either palliative therapy (n=14) or chemotherapy [n=54; CHOP therapy (n=37)/ VCAP-AMP-VECP therapy (n=17)], and showed median survival durations of 0.5 months and 7.4 months, respectively. The factors affecting OS by multivariate analysis were age, BUN, and CAR. Importantly, we revealed that the high CAR group (optimal cut-off point; 0.553) was a significant indicator of worse OS by multivariate analysis (p< 0.001, HR; 5.46). The median survival of patients with a CAR< 0.553 was 8.37 months, while patients with a CAR>0.553 had a median survival of 3.94 months. The different clinical features between high CAR and low CAR groups were hypoproteinemia and the implementation of chemotherapy. Furthermore, in the chemotherapy group, but not the palliative therapy group, CAR was a significant prognostic marker. Our study indicated that CAR may be a new simple and significant independent prognostic marker in acute- and lymphoma-type ATL patients.

CCR7 alterations associated with inferior outcome of adult T-cell leukemia/lymphoma under mogamulizumab treatment

Adult T-cell leukemia/lymphoma (ATL) patients have a very poor prognosis. The humanized anti-CCR4 therapeutic monoclonal antibody, mogamulizumab, is a key agent for ATL treatment. Our previous integrated molecular analysis demonstrated that among all the driver genes in ATL, CCR7 gene alterations were significantly associated with clinical response to mogamulizumab. Accordingly, here we investigated the detailed clinical impact of CCR7 alterations in a larger cohort of ATL patients. These CCR7 alterations, most of which lead to C-terminus truncations, were observed in 27 of 223 patients (12%). For patients receiving mogamulizumab but not allogeneic hematopoietic stem cell transplantation (HSCT), CCR7 alterations were significantly associated with worse survival (median survival from the first dose of mogamulizumab of 0.7 years for 12 patients with CCR7 alterations vs. 1.6 years for 72 patients without, p = 0.020). On the other hand, the presence or absence of CCR7 alterations had no significant impact on survival in the entire cohort (median overall survival of 1.4 and 1.8 years, respectively, p = 0.901), or on the survival of patients receiving allogeneic HSCT (median survival from the day of transplantation of 0.9 years for 6 patients with CCR7 alterations and 1.4 years for 48 without, p = 0.543). Multivariate analysis indicated that patients with CCR4 alterations but lacking CCR7 alterations (n = 20) had significantly better survival after receiving mogamulizumab-containing treatments (hazard ratio for survival, 0.437, 95% confidence interval, 0.192-0.994). This study contributes to the establishment of precision medicine for ATL.

The importance of the clinical classification of adult T-cell leukemia/lymphoma (ATLL) in the prognosis

BACKGROUND

Adult T-cell leukemia/lymphoma (ATLL), a peripheral T-cell leukemia/lymphoma associated with the human T-cell lymphotropic virus type-1 (HTLV-1), has been classified following the clinical forms defined by Shimoyama in 1991. A suggestion to modify Shimoyama's classification was proposed in 2007 to differentiate within the smoldering patients those who presented nodules or tumors in the skin without lung involvement, which was named the primary cutaneous tumoral (PCT) form of ATLL. In the present study, according to their clinicopathological characteristics, we estimated the mortality rates of 143 ATLL patients from Bahia, Brazil. We also evaluated the importance of classifying PCT/ATLL separately from the smoldering type on disease prognosis.

METHODOLOGY/PRINCIPAL FINDINGS

Diagnosis of ATLL was established based on a positive serology for HTLV-1, histopathological and/or cytological diagnosis of peripheral T-cell leukemia/lymphoma. Patients were clinically grouped according to Shimoyama's classification, considering PCT variants separately from the smoldering cases. Bivariate and multivariable survival analyses were applied to identify factors associated with disease prognosis. Significant differences in the median survival time were observed between the clinical types, with the smoldering type presenting the longest median survival (109 months) compared to the other forms (<50 months); the median survival for PCT/ATLL was 20 months. Multivariable analysis confirmed that ATLL clinical types were associated with survival, with a better prognosis for patients with the smoldering and chronic types. Furthermore, skin involvement was related to a worse outcome in the multivariable analysis, regardless of the clinical form and presence of lymphadenopathy.

CONCLUSIONS/SIGNIFICANCE

Our results reinforce the importance of considering the PCT/ATLL separately from the smoldering type when classifying ATLL to better define prognosis and treatment, given the significant difference in the survival of patients between the smoldering form and PCT/ATLL. Skin involvement should also be considered an independent prognostic factor in patients with ATLL.

KIR3DL2 contributes to the typing of acute adult T-cell leukemia and is a potential therapeutic target

Adult T-cell leukemia (ATL) is a lymphoid neoplasm caused by human T-cell leukemia virus type 1 (HTLV-1), which encodes the transcriptional activator Tax, which participates in the immortalization of infected T cells. ATL is classified into 4 subtypes: smoldering, chronic, acute, and lymphoma. We determined whether natural killer receptors (NKRs) were expressed in ATL. NKR expression (KIR2DL1/2DS1, KIR2DL2/2DL3/2DS2, KIR3DL2, NKG2A, NKG2C, and NKp46) was assessed in a discovery cohort of 21 ATL, and KIR3DL2 was then assessed in 71 patients with ATL. KIR3DL2 was the only NKR among those studied frequently expressed by acute-type vs lymphoma- and chronic/smoldering-type ATL (36 of 40, 4 of 16, and 1 of 15, respectively; P = .001), although acute- and lymphoma-type ATL had similar mutation profiles by targeted exome sequencing. The correlation of KIR3DL2 expression with promoter demethylation was determined by microarray-based DNA methylation profiling. To explore the role of HTLV-1, KIR3DL2 and TAX messenger RNA (mRNA) expression levels were assessed by PrimeFlow RNA in primary ATL and in CD4+ T cells infected with HTLV-1 in vitro. TAX mRNA and KIR3DL2 protein expressions were correlated on ATL cells. HTLV-1 infection triggered KIR3DL2 by CD4+ cells but Tax alone did not induce KIR3DL2 expression. Ex vivo, autologous, antibody-dependent cell cytotoxicity using lacutamab, a first-in-class anti-KIR3DL2 humanized antibody, selectively killed KIR3DL2+ primary ATL cells ex vivo. To conclude, KIR3DL2 expression is associated with acute-type ATL. Transcription of KIR3DL2 may be triggered by HTLV-1 infection and correlates with hypomethylation of the promoter. The benefit of targeting KIR3DL2 with lacutamab is being further explored in a randomized phase 2 study in peripheral T-cell lymphoma, including ATL (registered on https://clinicaltrials.gov as #NCT04984837).

HTLV-1-related adult T-cell leukemia/lymphoma: insights in early detection and management

PURPOSE OF REVIEW

Adult T-cell leukemia-lymphoma (ATL) is an aggressive mature T-cell malignancy that arises in approximately 5% of carriers of human T-lymphotropic virus type 1 (HTLV-1), but this risk is not random among carriers. We describe recent advance in pathogenesis, risk factors and for early detection of ATL.

RECENT FINDINGS

Unraveling ATL molecular genetics has shed light on pathogenesis and provides insights into novel therapeutic targets. Moreover, an important step in improving outcomes is identifying asymptomatic carriers who are at high risk of progression to ATL, which has traditionally relied on quantifying the proviral load (PVL). This can be done by quantifying oligoclonality- and in particular the expanded clone- with molecular and flow cytometric techniques, that can be applied to a clinical setting. Studies using these methods have shown that carriers with oligoclonal populations are at an increased risk of transformation, beyond that that predicted by PVL alone.

SUMMARY

There is an urgent unmet need for developing novel therapies in ATL in order to improve survival. Recent advances in the molecular and epigenetic landscape of ATL, and the early detection of disease offer the potential to intervene early, before disease becomes aggressive, and to offer tailored therapeutic strategies.

Panuveitis induced by donor-derived CD8+ T cells after allogeneic hematopoietic stem cell transplantation for adult T-cell leukemia

Purpose

This article presents a case of panuveitis that occurred after unrelated allogeneic hematopoietic stem cell transplantation (allo-HSCT) in a patient with lymphoma-type human T-cell leukemia virus type-1 (HTLV-1)-associated adult T-cell leukemia (ATL).

Observations

A 45-year-old man developed unilateral panuveitis 18 months after undergoing allo-HSCT. He underwent vitrectomy, and depositions of grey-white granules localized on the retinal artery were observed in the eye. Cytological examination of the vitreous aspirates showed that the atypical lymphoid cells stained positive for CD3 and CD8, but negative for CD4, B-cell markers, and cytomegalovirus antigen. Interphase fluorescence in situ hybridization using X‐ and Y‐chromosome probes revealed complete donor chimerism in CD8⁺ T cells in the vitreous aspirates.

Conclusions and importance

Donor-derived CD8⁺ T lymphocytes can induce panuveitis like HTLV-1-assiciated uveitis after allo-HSCT in patients with ATL. Pathological diagnosis of vitreous infiltration by vitrectomy is helpful in patients with ATL. Donor-derived CD8⁺ T lymphocytes-induced panuveitis is recurrent but susceptible to regional corticosteroid treatment.

•

/This is a primary case of panuveitis induced by donor-derived CD8⁺ T lymphocytes in a patient with aggressive ATL after allo-HSCT.

•

/Pathological diagnosis of vitreous infiltration by vitrectomy is helpful in patients with ATL to determine the phenotypes of cells infiltrating the eye of ATL patients.

•

/Donor-derived CD8⁺ T lymphocytes-induced panuveitis is recurrent but susceptible to regional corticosteroid treatment.

Primary cutaneous lymphoma: recommendations for clinical trial design and staging update from the ISCL, USCLC, and EORTC

The number of patients with primary cutaneous lymphoma (PCL) relative to other non-Hodgkin lymphomas (NHLs) is small and the number of subtypes large. Although clinical trial guidelines have been published for mycosis fungoides/Sézary syndrome, the most common type of PCL, none exist for the other PCLs. In addition, staging of the PCLs has been evolving based on new data on potential prognostic factors, diagnosis, and assessment methods of both skin and extracutaneous disease and a desire to align the latter with the Lugano guidelines for all NHLs. The International Society for Cutaneous Lymphomas (ISCL), the United States Cutaneous LymphomaConsortium (USCLC), and the Cutaneous Lymphoma Task Force of the European Organization for the Research and Treatment of Cancer (EORTC) now propose updated staging and guidelines for the study design, assessment, endpoints, and response criteria in clinical trials for all the PCLs in alignment with that of the Lugano guidelines. These recommendations provide standardized methodology that should facilitate planning and regulatory approval of new treatments for these lymphomas worldwide, encourage cooperative investigator-initiated trials, and help to assess the comparative efficacy of therapeutic agents tested across sites and studies.

Late presentation of HTLV-1 infection in Spain reflects suboptimal testing strategies

BACKGROUND

. Although only 10% of persons infected with HTLV-1 may develop virus-associated illnesses lifelong, missing the earlier diagnosis of asymptomatic carriers frequently leads to late presentation.

METHODS

. A nationwide HTLV-1 register was created in Spain in 1989. We examined the main demographics and clinical features at the time of first diagnosis during more than three decades.

RESULTS

. A total of 428 individuals infected with HTLV-1 had been reported in Spain until the end of 2021. Up to 96 (22%) individuals presented clinically with HTLV-1-associated conditions, including subacute myelopathy (57%), T-cell lymphoma (34%), or Strongyloides stercoralis infestation (8%). Since 2008, HTLV-1 diagnosis has been made either at blood banks (44%) or at clinics (56%). Native Spaniards and Sub-Saharan Africans are overepresented among patients presenting with HTLV-1-associated illnesses suggesting that poor epidemiological and/or clinical suspicion leading to late presentation are more frequent in them compared to LATAM carriers (31.7% vs 20.4%, respectively; p=0.015).

CONCLUSION

. HTLV-1 infection in Spain is frequently diagnosed in patients presenting with characteristic illnesses. Whereas screening in blood banks mostly identifies asymptomatic LATAM carriers, a disproportionately high number of Spaniards and Africans are diagnosed too late, at the time of clinical manifestations. Expanding testing to all pregnant women and clinics for sexually transmitted infections could help to unveil HTLV-1 asymptomatic carriers.

Interplay between innate immunity and the viral oncoproteins Tax and HBZ in the pathogenesis and therapeutic response of HTLV-1 associated adult T cell leukemia

The Human T-cell Leukemia virus type 1 (HTLV-1) causes an array of pathologies, the most aggressive of which is adult T-cell leukemia (ATL), a fatal blood malignancy with dismal prognosis. The progression of these diseases is partly ascribed to the failure of the immune system in controlling the spread of virally infected cells. HTLV-1 infected subjects, whether asymptomatic carriers or symptomatic patients are prone to opportunistic infections. An increasing body of literature emphasizes the interplay between HTLV-1, its associated pathologies, and the pivotal role of the host innate and adoptive immune system, in shaping the progression of HTLV-1 associated diseases and their response to therapy. In this review, we will describe the modalities adopted by the malignant ATL cells to subvert the host innate immune response with emphasis on the role of the two viral oncoproteins Tax and HBZ in this process. We will also provide a comprehensive overview on the function of innate immunity in the therapeutic response to chemotherapy, anti-viral or targeted therapies in the pre-clinical and clinical settings.

A Review of the Prevention of Mother-to-Child Transmission of Human T-Cell Lymphotrophic Virus Type 1 (HTLV-1) With a Proposed Management Algorithm

Human T cell lymphotropic virus type 1 (HTLV-1) is a human retrovirus that is endemic in a number of regions across the world. There are an estimated 5–10 million people infected worldwide. Japan is currently the only country with a national antenatal screening programme in place. HTLV-1 is primarily transmitted sexually in adulthood, however it can be transmitted from mother-to-child perinatally. This can occur transplacentally, during the birth process or via breastmilk. If HTLV-1 is transmitted perinatally then the lifetime risk of adult T cell leukemia/lymphoma rises from 5 to 20%, therefore prevention of mother-to-child transmission of HTLV-1 is a public health priority. There are reliable immunological and molecular tests available for HTLV-1 diagnosis during pregnancy and screening should be considered on a country by country basis. Further research on best management is needed particularly for pregnancies in women with high HTLV-1 viral load. A first step would be to establish an international registry of cases and to monitor outcomes for neonates and mothers. We have summarized key risk factors for mother-to-child transmission of HTLV-1 and subsequently propose a pragmatic guideline for management of mothers and infants in pregnancy and the perinatal period to reduce the risk of transmission. This is clinically relevant in order to reduce mother-to-child transmission of HTLV-1 and it's complications.