Consensus criteria for diagnosis, staging, and treatment response assessment of T-cell prolymphocytic leukemia

Dual STAT3/STAT5 inhibition as a novel treatment strategy in T-prolymphocytic leukemia

T-prolymphocytic leukemia (T-PLL) is a rare, aggressive T-cell malignancy with poor outcomes and an urgent need for new therapeutic approaches. Integrating genomic data and new transcriptomic profiling, we identified recurrent JAK/STAT mutations (predominantly in JAK3 and STAT5B) as hallmarks in a cohort of 335 T-PLL cases. In line, transcriptomic and protein analyses revealed constitutive JAK/STAT activation in virtually all samples. Consequently, we explored the anti-leukemic potential of dual STAT3/STAT5 non-PROTAC degraders in T-PLL, with JPX-1244 as our lead substance. JPX-1244 efficiently and selectively induced cell death in primary T-PLL samples, including those resistant to conventional therapies, by blocking STAT3 and STAT5 phosphorylation and by inducing their degradation. The extent of STAT3/STAT5 degradation directly correlated with cytotoxicity. RNA-sequencing confirmed the treatment-related downregulation of STAT5 target genes. While JAK/STAT mutations did not predict responses to pharmacologic STAT3/STAT5 degradation, elevated expression of TOX, PAK6, and SPINT1 were associated with drug sensitivity. In subsequent combination screenings, cladribine, venetoclax, and azacytidine emerged as most effective combination partners of STAT3/STAT5 degraders, even in low-responding T-PLL samples, all synergistically reducing STAT5 phosphorylation. These findings highlight dual STAT3/STAT5 inhibition, particularly in combination with hypomethylating and BCL2-targeting agents, as a promising interventional approach in T-PLL, warranting further investigation.

Real-world safety and effectiveness of alemtuzumab for relapsed or refractory chronic lymphocytic leukaemia: results from postmarketing surveillance in Japan

BACKGROUND

Alemtuzumab is a monoclonal antibody directed against CD52 on T and B lymphocytes and is used to treat lymphoproliferative disorders including chronic lymphocytic leukaemia (CLL). This postmarketing surveillance, as mandated by the Japanese health authorities, investigated the safety and effectiveness of alemtuzumab in Japanese patients receiving alemtuzumab for relapsed/refractory CLL.

METHODS

This was an observational, prospective study conducted in patients with lymphoproliferative disorders who received alemtuzumab in routine clinical practice in Japan between March 2015 and June 2023. Follow-up was for 24 weeks after alemtuzumab administration. Endpoints were adverse drug reactions (ADRs), objective response rate (ORR), progression-free survival (PFS) and overall survival (OS), and factors associated with safety and effectiveness.

RESULTS

Safety was evaluated in 179 patients with lymphoproliferative disorders (112 males and 67 females; median age 68 years) and effectiveness in 95 with relapsed/refractory CLL. Overall, 138 patients (77.1%) developed an ADR (most commonly cytomegalovirus [CMV]-related events [37.4%]), 100 (55.9%) developed serious ADRs (most commonly CMV-related events [31.3%]), and 93 (52.0%) developed grade ≥ 3 ADRs (most commonly decreased platelet count [13.4%]). Of 95 patients with relapsed/refractory CLL, 39 (41.1%) had an ORR (15 complete and 24 partial responses). At 24 weeks, PFS and OS rates were 55.5% and 70.0%, respectively. The ORR was significantly associated with Rai classification, performance status, and treatment days or duration.

CONCLUSIONS

This prospective postmarketing surveillance study confirms the effectiveness and manageable safety profile of alemtuzumab for Japanese patients with relapsed/refractory CLL.

Altered immune cell profiles in blood of mature/peripheral T-cell leukemia/lymphoma patients: an EuroFlow study

Introduction

The interactions between T-cell chronic lymphoproliferative disorder (T-CLPD) tumor cells and the bystander immune cells may play a critical role in the failure of immune surveillance and disease progression, but the altered blood immune profiles of T-CLPD remain unknown.

Methods

Here we analyzed the distribution of residual non-tumoral immune cells in blood of 47 T-CLPD patients -14 T-prolymphocytic leukemia (T-PLL), 7 Sézary syndrome/mycosis fungoides (SS/MF) and 26 T-large granular lymphocytic leukemia (T-LGLL)-, as tumor models of neoplastic T-cells that resemble naive/central memory (N/CM), memory and terminal effector T-cells, respectively, compared to 110 age- and sex-matched healthy donors, using spectral flow cytometry.

Results

Overall, our results showed deeply altered immune cell profiles in T-PLL, characterized by significantly increased counts of monocytes, dendritic cells, B-cells, NK-cells and innate lymphoid cells (ILC) -particularly ILC3-, together with reduced normal T-cells. In contrast, SS/MF showed neutrophilia, associated with decreased numbers of dendritic cells and NK-cells, potentially reflecting their increased migration from blood to the skin. In turn, T-LGLL displayed the mildest immune impairment, dependent on the TCD4+ vs. TCD8+ nature of the clonal T-cells and presence of STAT3 mutations among TαβCD8+ T-LGLL cases. Further dissection of the normal T-cell compartment showed a significant reduction of the earliest T-cell maturation compartments (N/CM) in T-PLL and SS/MF, whereas T-cells remained within normal ranges in T-LGLL, with only a minor reduction of N/CM T-cells.

Conclusion

These findings point out the existence of differentially altered innate and adaptive immune cell profiles in the distinct diagnostic subtypes of T-CLPD, with progressively less pronounced alterations from T-PLL and SS/MF to T-LGLL.

T-cell prolymphocytic leukemia, a case report and review of the literature

T-prolymphocytic leukemia is a rare and aggressive hematological malignancy characterized by the clonal proliferation of mature lymphoid T-cells. The pathogenesis of T-PLL is closely linked to specific chromosomal abnormalities, primarily involving the proto-oncogene T-cell leukemia/lymphoma 1 gene family. Recent advancements in molecular profiling have identified additional genomic aberrations, including those affecting the Janus kinase/signal transducers and activators of transcription (JAK/STAT) signaling pathway. This case report presents a patient with T-prolymphocytic leukemia whose cytogenetic and molecular analysis revealed a t(X;14)(q28;q11.2) translocation and a STAT5B mutation. Here, we aim to review the genetic and molecular underpinnings of T-prolymphocytic leukemia, as well as current treatment options, with a focus on the anti-CD52 monoclonal antibody alemtuzumab and JAK inhibitors. While alemtuzumab followed by allogeneic hematopoietic stem cell transplantation remains the standard of care for eligible patients, its efficacy is limited and many patients are ineligible. Emerging therapeutic approaches, such as JAK/STAT inhibitors, offer promising potential for improving patient outcomes.

Immunophenotypic, genetic, and clinical characterization of adult T-cell leukemia/lymphoma: A single tertiary care center experience in the United States

OBJECTIVES

Adult T-cell leukemia/lymphoma (ATLL) is an aggressive mature T-cell neoplasm caused by human T-cell lymphotropic virus type 1 (HTLV-1). Its most common immunophenotype is CD4+/CD7-/CD25+, although unusual immunophenotypes can occur and may lead to misdiagnosis.

METHODS

The immunophenotypes, cytogenetics, molecular features, clinical presentations, treatment, and prognosis of 131 patients with ATLL were retrospectively studied in a large tertiary medical center in the United States.

RESULTS

All cases showed loss of CD7 expression. While 82.4% of cases demonstrated CD4+, 17.6% exhibited unusual phenotypes, including CD4+/CD8+ (6.9%), CD4-/CD8- (2.3%), CD5- (3.1%), CD2-, and CD3-. The most common cytogenetics abnormalities included polysomy 3 (34.6%), translocation 1 (23.1%), and abnormalities found on chromosome 11 (30.8%) and chromosome 14 (26.9%). The common gene mutations identified by the next-generation sequencing study were TP53 (16.7%), TBL1XR1 (16.7%), EP300 (14.3%), and NOTCH1 (14.3%). TBL1XR1 mutation is associated with genetic instabilities. There was no significant difference between the clinical presentations of these 2 groups.

CONCLUSIONS

Adult T-cell leukemia/lymphoma exhibits versatile immunophenotypic, cytogenetic, and molecular features. Simultaneous involvement of blood, lymph nodes, and other organs, along with hypercalcemia in a patient from an endemic area, necessitates HTLV-1 testing to avoid underdiagnosis of this dismal disease that might need aggressive chemotherapy followed by bone marrow transplant.

An in-depth understanding of the role and mechanisms of T cells in immune organ aging and age-related diseases

T cells play a critical and irreplaceable role in maintaining overall health. However, their functions undergo alterations as individuals age. It is of utmost importance to comprehend the specific characteristics of T-cell aging, as this knowledge is crucial for gaining deeper insights into the pathogenesis of aging-related diseases and developing effective therapeutic strategies. In this review, we have thoroughly examined the existing studies on the characteristics of immune organ aging. Furthermore, we elucidated the changes and potential mechanisms that occur in T cells during the aging process. Additionally, we have discussed the latest research advancements pertaining to T-cell aging-related diseases. These findings provide a fresh perspective for the study of T cells in the context of aging.

Oral manifestations of peripheral T cell lymphoma, not otherwise specified: case series and review of the current literature

OBJECTIVE

The objective of this study was to describe a series of peripheral T-cell lymphoma, not otherwise specified (PTCL NOS) affecting the oral cavity and to review the available literature.

STUDY DESIGN

Cases diagnosed as PTCL-NOS affecting the oral cavity were retrospectively retrieved from pathology files. Original hematoxylin and eosin-stained slides and immunohistochemical reactions were reviewed for microscopic confirmation. The presence of Epstein-Barr virus (EBV) was investigated by in situ hybridization. Clinical and follow-up data were retrieved from patients' pathology and medical files.

RESULTS

A total of 5 cases were obtained with a mean age of 51.8 years old, 3 male patients and 2 female patients. Three cases affected the palate and 2 cases affected the gingiva, whereas 1 case affected the maxillary bone. Tumors presented as destructive, infiltrative, and painful lesions causing swelling, ulceration, and tissue necrosis. All cases exhibited CD3 expression. GATA3 was expressed in 3 cases. Four patients were deceased of the disease during follow-up.

CONCLUSIONS

PTCL NOS affecting the oral cavity is rare and usually present as a very aggressive disease, associated with a poor prognosis and dismal outcome. (Oral Surg Oral Med Oral Pathol Oral Radiol YEAR;VOL:page range).

Hierarchical DNA Octahedral Nanoplatform for in Situ Biosensing and Clinical Monitoring of Acute Lymphoblastic Leukemia

Developing nanoscale platforms with high integration, assembly efficiency, and structural stability for performing complex computations in specific cells remains a significant challenge. To address this, the Three-dimensional Hierarchical Octahedral Robotic (THOR) DNA nanoplatform is introduced, which integrates targeting, logic computation, and sensing modules within a single framework. This nanoplatform specifically binds to cancer cell surface proteins, releasing aptamer-linked fuel chains to initiate subsequent computational processes. Three logic gates efficiently compute any arbitrary binary combination of target proteins. The sensing module employs catalytic hairpin assembly for detecting specific miRNAs with high sensitivity. THOR demonstrates robust functionality both in vitro and in situ. As a proof-of-concept, this nanoplatform to distinguish acute lymphoblastic leukemia (ALL) patients from other leukemia subtypes and healthy participants, achieving 100% accuracy is applied. Additionally, this approach reliably monitored the therapeutic progress of ALL patients, showing strong concordance with bone marrow smear results. The THOR platform highlights the feasibility of constructing a reliable, hierarchical, and multifunctional analytical system based on a single DNA polyhedron. It offers a promising auxiliary tool for clinical diagnostics and therapeutic monitoring.

Proteasome Inhibitors Induce Apoptosis in Ex Vivo Cells of T-Cell Prolymphocytic Leukemia

Finding an effective treatment for T-PLL patients remains a significant challenge. Alemtuzumab, currently the gold standard, is insufficient in managing the aggressiveness of the disease in the long term. Consequently, numerous efforts are underway to address this unmet clinical need. The rarity of the disease limits the ability to conduct robust clinical trials, making in silico, ex vivo, and in vivo drug screenings essential for designing new therapeutic strategies for T-PLL. We conducted a drug repurposing analysis based on T-PLL gene expression data and identified proteasome inhibitors (PIs) as a promising new class of compounds capable of reversing the T-PLL phenotype. Treatment of ex vivo T-PLL cells with Bortezomib and Carfilzomib, two PI compounds, supported this hypothesis by demonstrating increased apoptosis in leukemic cells. The current lack of a suitable in vitro model for the study of T-PLL prompted us to perform similar experiments in the SUP-T11 cell line, validating its potential by showing an increased apoptotic rate. Taken together, these findings open new avenues for investigating the molecular mechanisms underlying the efficacy of PI in T-PLL and expand the spectrum of potential therapeutic strategies for this highly aggressive disease.

A practical approach to the modern diagnosis and classification of T- and NK-cell lymphomas

ABSTRACT

T- and natural killer (NK)-cell lymphomas are neoplasms derived from immature T cells (lymphoblastic lymphomas), or more commonly, from mature T and NK cells (peripheral T-cell lymphomas, PTCLs). PTCLs are rare but show marked biological and clinical diversity. They are usually aggressive and may present in lymph nodes, blood, bone marrow, or other organs. More than 30 T/NK-cell-derived neoplastic entities are recognized in the International Consensus Classification and the classification of the World Health Organization (fifth edition), both published in 2022, which integrate the most recent knowledge in hematology, immunology, pathology, and genetics. In both proposals, disease definition aims to integrate clinical features, etiology, implied cell of origin, morphology, phenotype, and genetic features into biologically and clinically relevant clinicopathologic entities. Cell derivation from innate immune cells or specific functional subsets of CD4+ T cells such as follicular helper T cells is a major determinant delineating entities. Accurate diagnosis of T/NK-cell lymphoma is essential for clinical management and mostly relies on tissue biopsies. Because the histological presentation may be heterogeneous and overlaps with that of many benign lymphoid proliferations and B-cell lymphomas, the diagnosis is often challenging. Disease location, morphology, and immunophenotyping remain the main features guiding the diagnosis, often complemented by genetic analysis including clonality and high-throughput sequencing mutational studies. This review provides a comprehensive overview of the classification and diagnosis of T-cell lymphoma in the context of current concepts and scientific knowledge.

Optimizing drug combinations for T-PLL: restoring DNA damage and P53-mediated apoptotic responses

ABSTRACT

T-prolymphocytic leukemia (T-PLL) is a mature T-cell neoplasm associated with marked chemotherapy resistance and continued poor clinical outcomes. Current treatments, that is, the CD52-antibody alemtuzumab, offer transient responses, with relapses being almost inevitable without consolidating allogeneic transplantation. Recent more detailed concepts of T-PLL's pathobiology fostered the identification of actionable vulnerabilities: (1) altered epigenetics, (2) defective DNA damage responses, (3) aberrant cell-cycle regulation, and (4) deregulated prosurvival pathways, including T-cell receptor and JAK/STAT signaling. To further develop related preclinical therapeutic concepts, we studied inhibitors of histone deacetylases ([H]DACs), B-cell lymphoma 2 (BCL2), cyclin-dependent kinase (CDK), mouse double minute 2 (MDM2), and classical cytostatics, using (1) single-agent and combinatorial compound testing in 20 well-characterized and molecularly profiled primary T-PLL (validated by additional 42 cases) and (2) 2 independent murine models (syngeneic transplants and patient-derived xenografts). Overall, the most efficient/selective single agents and combinations (in vitro and in mice) included cladribine, romidepsin ([H]DAC), venetoclax (BCL2), and/or idasanutlin (MDM2). Cladribine sensitivity correlated with expression of its target RRM2. T-PLL cells revealed low overall apoptotic priming with heterogeneous dependencies on BCL2 proteins. In additional 38 T-cell leukemia/lymphoma lines, TP53 mutations were associated with resistance toward MDM2 inhibitors. P53 of T-PLL cells, predominantly in wild-type configuration, was amenable to MDM2 inhibition, which increased its MDM2-unbound fraction. This facilitated P53 activation and downstream signals (including enhanced accessibility of target-gene chromatin regions), in particular synergy with insults by cladribine. Our data emphasize the therapeutic potential of pharmacologic strategies to reinstate P53-mediated apoptotic responses. The identified efficacies and their synergies provide an informative background on compound and patient selection for trial designs in T-PLL.

Applications of 18F-Fluorodesoxyglucose PET Imaging in Leukemia

The main finding that 18F-FDG PET imaging can reveal in patients with leukemias is the presence of bone marrow (BM) infiltration in both acute or chronic forms. This ability can influence and guide the use of BM biopsy but also assess to therapy response. Additionally 18F-FDG PET imaging has been reported as particularly useful for the diagnosis of leukemias in patients with non specific symptoms. In the case of acute leukemias it revealed also a role for the evaluation of extramedullary forms while in the case of chronic forms a role for the assessment of Richter transformation has been reported.

Alemtuzumab monotherapy for T-cell prolymphocytic leukemia: an observational study in Japan

Alemtuzumab is recommended as first-line and second-line therapies for T-cell prolymphocytic leukemia (T-PLL). This study retrospectively evaluated the efficacy and safety of alemtuzumab in nine Japanese patients with T-PLL at five participating institutions who were treated between January 2015 and August 2023. The median age at first administration of alemtuzumab was 72 years (range, 39 to 78). Two patients were treatment naïve, and seven had been treated with a median of one (range, 1 to 3) prior systemic therapy. Six patients were refractory to their most recent therapy. Three patients completed 12 weeks of treatment. The overall response rate and the complete response (CR) rate were 78% and 11%, respectively. Among the six patients who achieved a partial response, two achieved clinical CR but did not undergo bone marrow examination. One patient also achieved clinical CR but did not undergo CT and bone marrow examination for response evaluation. The median progression-free survival time was 8.1 months (95% confidence interval, 0.9 to 18.6). Three patients received readministration of alemtuzumab monotherapy after disease progression. There were no treatment-related deaths. The grade 3 or 4 nonhematologic adverse events included infusion reaction (grade 3, n = 2), cytomegalovirus reactivation (grade 3, n = 2), and pulmonary edema (grade 3, n = 1). One patient experienced Epstein‒Barr virus-positive diffuse large B-cell lymphoma 15 months after the last dose of alemtuzumab. These results confirm that the efficacy and safety of alemtuzumab monotherapy in Japanese patients are comparable to those previously reported.

Acute Coronary Syndrome as an Unusual Initial Presentation of T-Prolymphocytic Leukemia: A Case Report and Review of the Literature

T-prolymphocytic leukaemia (T-PLL) is the most common mature T-cell leukaemia in Central Europe and is often manifested by rapidly increasing lymphocytosis, marked bone marrow infiltration and splenomegaly. In 10-15% of cases, the diagnosis is made by incidental findings in otherwise asymptomatic patients. Here we report a case of T-PLL that initially became symptomatic due to the presence of acute coronary syndrome (ACS). Initially, emergency coronary angiography with consecutive emergency 5-coronary artery bypass grafting (CABG) was performed. Leukocytosis was found perioperatively and T-PLL (with TCL1 rearrangement) was subsequently diagnosed. Despite known potential cardiotoxicity, the patient was treated with the anti-CD52 antibody alemtuzumab with a gradual dose increase from 3 mg to 30 mg per day. Systemic alemtuzumab therapy resulted in the complete remission of T-PLL in the bone marrow without any impairment to cardiac function. The patient was then eligible to undergo a consolidating allogeneic stem cell transplant (alloSCT). The reported case shows that T-PLL can also become initially symptomatic through an acute coronary syndrome on the basis of complex coronary heart disease. Targeted antileukaemic therapy with the monoclonal antibody alemzutumab can lead to effective systemic cytoreduction without cardiac dysfunction even in patients with severe cardiac disease, although cases of cardiotoxicity have been reported.

Does a subset of mature T-cell leukemias with features akin to T-cell prolymphocytic leukemia but lacking rearrangement of the TCL1 represent peripheral T-cell lymphoma, NOS in a leukemic phase?

In the current WHO classification, a T-cell prolymphocytic leukemia (T-PLL) diagnosis requires lymphocytosis of >5 × 109/L, evidence of monoclonality, and TCL1A or MTCP1 rearrangement. However, the 2019 consensus document suggested that in the absence of rearrangement of TCL1-family, the presence of abnormalities involving chromosome 11 (11q22.3; ATM), chromosome 8 (idic(8)(p11), t(8;8), trisomy 8q), 5, 12, 13, 22, or a complex karyotype, as well as involvement specific sites (e.g., splenomegaly, effusions) would suffice for a diagnosis of T-PLL. We present a patient diagnosed with T-PLL with MTCP1 rearrangement who was successfully treated with alemtuzumab followed by consolidative allogeneic unrelated donor stem cell transplantation. Eight years later, the patient presented with inguinal lymphadenopathy with features more akin to peripheral T-cell lymphoma, NOS (PTCL, NOS) of the GATA3 subtype, and there was no evidence of peripheral blood involvement. However, the lymphoma cells were clonally related to those at presentation. Currently, literature on T-PLL-like cases lacking the rearrangement of TCL1A is limited, and the possibility of whether a proportion of such cases could represent PTCL, NOS (with leukemic involvement) needs consideration.

Glutathione overproduction mediates lymphoma initiating cells survival and has a sex-dependent effect on lymphomagenesis

Lymphoid tumor patients often exhibit resistance to standard therapies or experience relapse post-remission. Relapse is driven by Tumor Initiating Cells (TICs), a subset of tumor cells capable of regrowing the tumor and highly resistant to therapy. Growing cells in 3D gels is a method to discern tumorigenic cells because it strongly correlates with tumorigenicity. The finding that TICs, rather than differentiated tumor cells, grow in 3D gels offers a unique opportunity to unveil TIC-specific signaling pathways and therapeutic targets common to various cancer types. Here, we show that culturing lymphoid cells in 3D gels triggers reactive oxygen species (ROS) production, leading to non-tumor lymphoid cell death while enabling the survival and proliferation of a subset of lymphoma/leukemia cells, TICs or TIC-like cells. Treatment with the antioxidant N-acetylcysteine inhibits this lethality and promotes the growth of primary non-tumor lymphoid cells in 3D gels. A subset of lymphoma cells, characterized by an increased abundance of the antioxidant glutathione, escape ROS-induced lethality, a response not seen in non-tumor cells. Reducing glutathione production in lymphoma cells, either through pharmacological inhibition of glutamate cysteine ligase (GCL), the enzyme catalyzing the rate-limiting step in glutathione biosynthesis, or via knockdown of GCLC, the GCL catalytic subunit, sharply decreased cell growth in 3D gels and xenografts. Tumor cells from B-cell lymphoma/leukemia patients and λ-MYC mice, a B-cell lymphoma mouse model, overproduce glutathione. Importantly, pharmacological GCL inhibition hindered lymphoma growth in female λ-MYC mice, suggesting that this treatment holds promise as a therapeutic strategy for female lymphoma/leukemia patients.

T-PLL Presenting with an Indolent Course

T-cell prolymphocytic leukemia (T-PLL) is a rare, mature T-cell leukemia which usually presents with aggressive behavior. We report an asymptomatic T-PLL patient diagnosed by clinical features, lymphocyte morphology, and flow cytometry. Incidentally, she was found to have lymphocytosis and lymphadenopathy. Flow cytometry from blood revealed an abnormally increased CD4+ T-cell population. T-cell receptor clonality assessment by next-generation sequencing revealed a dominant clone in the ß-chain constant region. No pathogenic mutations in 25 lymphoma-related genes were found. Due to her asymptomatic T-PLL disease, we observed her clinical situation and blood count every three months for at least one year.

Morphology, immunophenotype, and suggested diagnostic criteria of TCL1 family-negative T-prolymphocytic leukemia

OBJECTIVES

We sought to investigate the morphologic and immunophenotypic characteristics of TCL1 family-negative T-cell prolymphocytic leukemia (T-PLL).

METHODS

Twenty cases of TCL1 family-negative T-PLL were studied.

RESULTS

The doubling time of leukemic cells ranged from less than 2 days to more than 5 years, with a median of 5.5 months. Leukemic cells were small to medium-sized, with round to irregular nuclei, variably condensed chromatin, and small amounts of agranular cytoplasm. A visible nucleolus was identified in 11 (55%) cases. Cytoplasmic blebs/protrusions were identified in all cases, but their occurrence was highly variable from case to case. Bone marrow biopsy showed an interstitial pattern in 90% of cases and a diffuse pattern in the remaining 10% of cases. Flow cytometric immunophenotypic analysis showed that the leukemic cells in all cases were CD4 positive; 3 (15%) also showed concurrent CD8 expression. All cases were positive for CD2 and CD5. Surface CD3 and CD7 were positive in 19 of 20 (95%) cases, and all CD3-positive cases expressed the T-cell receptor αβ. Compared with prototypic T-PLL cases, these 2 groups shared many immunophenotypic findings, except CD8 and CD26, both of which were more commonly expressed in prototypic T-PLL cases.

CONCLUSIONS

TCL1 family-negative T-PLL cases have morphologic and immunophenotypic features that are similar to prototypic T-PLL. They are characterized by neoplastic proliferation of small to medium-sized mature T cells with CD4-positive T-cell receptor αβ phenotype. Tumor cells frequently maintain pan-T antigen expression. Recognizing these morphologic and immunophenotypic features will aid in accurately diagnosing this rare subset of T-PLL.

Molecular Pathology of Mature Lymphoid Malignancies

Lymphoid malignancies are a broad and heterogeneous group of neoplasms. In the past decade, the genetic landscape of these tumors has been explored and cataloged in fine detail offering a glimpse into the mechanisms of lymphomagenesis and new opportunities to translate these findings into patient management. A myriad of studies have demonstrated both distinctive and overlapping molecular and chromosomal abnormalities that have influenced the diagnosis and classification of lymphoma, disease prognosis, and treatment selection.

Disseminated Cryptococcosis With Prostate Involvement in a Patient With T-cell Prolymphocytic Leukemia and Prostate Cancer

T-cell prolymphocytic leukemia (T-PLL) presents unique treatment challenges because of its rarity and aggressiveness. Allogeneic hematopoietic stem cell transplantation offers a potentially curative option, but its safety in patients with concurrent invasive fungal infections and solid malignancies remains uncertain. We present a case of a 68-year-old male with T-PLL who developed disseminated cryptococcal disease with prostate involvement and concurrent prostate cancer (PCa). Despite the challenges, successful control of the infection and radical prostatectomy enabled the patient to proceed safely to allogeneic transplantation. The case highlights the importance of vigilance for unusual infections, such as Cryptococcus, in immunocompromised patients presenting with lower urinary tract symptoms. Clinicians should consider the possibility of PCa in this population, particularly in the context of chronic leukemia. Concurrently, the potential association between fungal prostate infections and PCa warrants further investigation.

Autologous hematopoietic cell transplantation for T-cell prolymphocytic leukemia: a retrospective study on behalf of the Chronic Malignancies Working Party of the EBMT

Not available.

Section E6.1-6.6 of the American College of Medical Genetics and Genomics (ACMG) Technical Laboratory Standards: Cytogenomic studies of acquired chromosomal abnormalities in neoplastic blood, bone marrow, and lymph nodes

Cytogenomic analyses of acquired clonal chromosomal abnormalities in neoplastic blood, bone marrow, and/or lymph nodes are instrumental in the clinical management of patients with hematologic neoplasms. Cytogenetic analyses assist in the diagnosis of such disorders and can provide important prognostic information. Furthermore, cytogenetic studies can provide crucial information regarding specific genetically defined subtypes of these neoplasms that may have targeted therapies. At time of relapse, cytogenetic analysis can confirm recurrence of the original neoplasm, detect clonal disease evolution, or uncover a new unrelated neoplastic process. This section deals specifically with the technical standards applicable to cytogenomic studies of acquired clonal chromosomal abnormalities in neoplastic blood, bone marrow, and/or lymph nodes. This updated Section E6.1-6.6 supersedes the previous Section E6 in Section E: Clinical Cytogenetics of the American College of Medical Genetics and Genomics Technical Standards for Clinical Genetics Laboratories.

T-cell prolymphocytic leukemia: Epidemiology and survival trends in the era of novel treatments

Survival remains poor for T-cell prolymphocytic leukemia, though treatment in recent years, associated with access to novel therapies, and management at academic medical centers is associated with improved outcomes. There remains a critical need to improve the available treatment options for this population, and access to specialized academic medical centers, comprehensive supportive care, clinical trials, and early palliative care remains essential for T-PLL patients.

Prolymphocytic Leukaemia: an Update on Biology and Treatment

PURPOSE OF REVIEW

This review summarises the recent advances in knowledge regarding the biology and treatment of prolymphocytic leukaemias.

RECENT FINDINGS

Both B-PLL and T-PLL are genetically complex, and the molecular landscape of these diseases has been well characterised recently. Diagnostic criteria for T-PLL have been refined with the publication of the first international consensus criteria, whereas the diagnosis of B-PLL has been thrown into question by the most recent WHO classification. Treatment advances in B-PLL have relied heavily on the advances seen in CLL that have then been extrapolated to B-PLL with just a few case reports to support the use of these targeted inhibitors. Despite increased knowledge of the biology of T-PLL and some elegant pre-clinical models to identify potential treatments, unfortunately, no improvements have been made in the treatment of T-PLL. Unmet need is a term oft used for many diseases, but this is particularly true for patients with prolymphocytic leukaemias. Ongoing improvements in our understanding of these diseases will hopefully lead to improved therapies in the future.

C-X-C Motif Chemokine Receptor 4-Targeted Radioligand Therapy in Hematological Malignancies-Myeloablative Effects, Antilymphoma Activity, and Safety Profile

BACKGROUND

After C-X-C motif chemokine receptor 4 (CXCR4)-directed radioligand therapy (RLT), lymphoma patients are scheduled for conditioning therapy (CON) followed by hematopoietic stem cell transplantation (HSCT). We aimed to determine whether CXCR4-RLT can achieve bone marrow ablation and direct antilymphoma activity independent from CON/HSCT and also evaluated the safety profile of this theranostic approach in an acute setting.

PATIENTS AND METHODS

After CXCR4-directed 68 Ga-pentixafor PET/CT, 21 heavily pretreated patients with hematological malignancies underwent CXCR4-directed RLT using 90 Y-pentixather. The extent of myeloablative efficacy was determined by investigating hematologic laboratory parameters before RLT (day -1), at the day of RLT (day 0), 2 days after RLT (day 2), and before CON (median day 10). Serving as surrogate marker of antilymphoma activity, lactate dehydrogenase (LDH) levels were also assessed until CON. We also screened for laboratory-defined tumor lysis syndrome after the Cairo-Bishop definition and recorded acute laboratory adverse events using the Common Terminology Criteria for Adverse Events version 5.0.

RESULTS

After RLT, we observed a significant decline of leukocyte levels by 79.4% ± 18.7% till CON (granulocytes, drop by 70.3% ± 21%; platelets, reduction by 43.1% ± 36%; P ≤ 0.0005 vs day 0, respectively). After RLT, LDH levels already reached a peak at day 2, which was followed by a rapid decline thereafter (peak vs day of CON, P = 0.0006), indicating that 90 Y-pentixather exhibits direct antilymphoma activity. At day of CON, LDH levels were also significantly lower when compared with day -1 ( P = 0.04), suggestive for durable response mediated by RLT. No patient fulfilled the criteria of tumor lysis syndrome, whereas 25 laboratory adverse events attributable to CXCR4-directed treatment were identified (≥grade 3 in 2/25 [8%]). During further treatment course, all patients (100%) received HSCT.

CONCLUSIONS

CXCR4-directed RLT causes effective myeloablation, which allows for HSCT. In addition, it also exerts direct antilymphoma activity independent of subsequent therapeutic steps, whereas safety profile was acceptable.

Updates in the Classification of T-cell Lymphomas and Lymphoproliferative Disorders

PURPOSE OF REVIEW

Mature T/NK-cell neoplasms comprise a heterogeneous group of diseases with diverse clinical, histopathologic, immunophenotypic, and molecular features. A clinically relevant, comprehensive, and reproducible classification system for T/NK-cell neoplasms is essential for optimal management, risk stratification, and advancing understanding of these diseases. Two classification systems for lymphoid neoplasms were recently introduced: the 5th edition of World Health Organization classification (WHO-HAEM5) and the 2022 International Consensus Classification (ICC). In this review, we summarize the basic framework and updates in the classification of mature T/NK-cell neoplasms.

RECENT FINDINGS

WHO-HAEM5 and ICC share basic concepts in classification of T/NK-cell neoplasms, emphasizing integration of clinical presentation, pathology, immunophenotype, and genetics. Major updates in both classifications include unifying nodal T-follicular helper-cell lymphomas into a single entity and establishing EBV-positive nodal T/NK-cell lymphoma as a distinct entity. However, some differences exist in taxonomy, terminology, and disease definitions. The recent classifications of mature T/NK-cell neoplasms are largely similar and provide new insights into taxonomy based on integrated clinicopathologic features.

Partial response to venetoclax and ruxolitinib combination in a case of refractory T-prolymphocytic leukemia

Background: T-prolymphocytic leukemia (T-PLL) is an aggressive hematologic malignancy. A portion of patients can be cured with alemtuzumab induction followed by allogeneic hematopoietic stem cell transplant, but patients who relapse after transplant have a poor prognosis, and there is no standard of care.Methods: We report a case of a 64-year-old man with relapsed JAK3-mutant T-PLL following allogeneic transplant who was treated with ruxolitinib and venetoclax.Results: Treatment with ruxolitinib and venetoclax resulted in a partial response including stabilization of the peripheral lymphocyte count, improvement in thrombocytopenia, decrease in splenomegaly, and a numerical reduction in the percentage of bone marrow involved by T-PLL. The combination was well tolerated with the exception of neutropenic infections.Conclusion: This case adds to the growing body of literature supporting venetoclax and rituximab as a viable treatment option for relapsed/refractory T-PLL with JAK-STAT alterations.

Long-Smoldering T-prolymphocytic Leukemia: A Case Report and a Review of the Literature

T-prolymphocytic leukemia (T-PLL) is a rare malignancy of mature T-cells with distinct clinical, cytomorphological, and molecular genetic features. The disease typically presents at an advanced stage, with marked leukocytosis, B symptoms, hepatosplenomegaly, and bone marrow failure. It usually follows an aggressive course from presentation, and the prognosis is often considered dismal; the median overall survival is less than one year with conventional chemotherapy. This case report describes a patient with T-PLL who, after an unusually protracted inactive phase, ultimately progressed to a highly invasive, organ-involving disease. After initial treatments failed, a novel treatment approach resulted in a significant response.

Cytogenetics in the management of mature T-cell and NK-cell neoplasms: Guidelines from the Groupe Francophone de Cytogénétique Hématologique (GFCH)

Mature T-cell and natural killer (NK)-cell neoplasms (MTNKNs) are a highly heterogeneous group of lymphomas that represent 10-15 % of lymphoid neoplasms and have usually an aggressive behavior. Diagnosis can be challenging due to their overlapping clinical, histological and immunophenotypic features. Genetic data are not a routine component of the diagnostic algorithm for most MTNKNs. Indeed, unlike B-cell lymphomas, the genomic landscape of MTNKNs is not fully understood. Only few characteristic rearrangements can be easily identified with conventional cytogenetic methods and are an integral part of the diagnostic criteria, for instance the t(14;14)/inv(14) or t(X;14) abnormality harbored by 95 % of patients with T-cell prolymphocytic leukemia, or the ALK gene translocation observed in some forms of anaplastic large cell lymphoma. However, advances in molecular and cytogenetic techniques have brought new insights into MTNKN pathogenesis. Several recurrent genetic alterations have been identified, such as chromosomal losses involving tumor suppressor genes (SETD2, CDKN2A, TP53) and gains involving oncogenes (MYC), activating mutations in signaling pathways (JAK-STAT, RAS), and epigenetic dysregulation, that have improved our understanding of these pathologies. This work provides an overview of the cytogenetics knowledge in MTNKNs in the context of the new World Health Organization classification and the International Consensus Classification of hematolymphoid tumors. It describes key genetic alterations and their clinical implications. It also proposes recommendations on cytogenetic methods for MTNKN diagnosis.

Clinical analysis of prolymphoblastic leukemia: the rare hematological malignancy in the elderly

OBJECTIVE

To discuss and analyze the clinical and prognostic characteristics of rare prolymphocytic leukemia (PLL), in order to provide new references for the clinical diagnosis and treatment and basic research of PLL.

METHODS

The clinical data of 8 patients with PLL admitted to the Department of Hematology in Fujian Medical University Union Hospital from January 1, 2011 to May 31, 2023 were collected and retrospectively studied, and the clinical treatment and prognosis were analyzed. Meanwhile, the latest literature from PubMed was retrieved to systematically discuss the research progress in the diagnosis and treatment of PLL.

RESULTS

In this study, of the 8 patients with PLL, 6 were males and 2 were females; the ages ranged from 52 to 80 years, with a median age of 70.5 years. The immunophenotypes were divided into B-PLL (7 cases) and T-PLL (1 case). Morphological, flow cytometric, cytogenetic and molecular biological tests of bone marrow cells were performed in all patients. Among them, 1 case refused chemotherapy after diagnosis and died in a short time, the other 7 cases received standard chemotherapy. Among the 7 patients, one patient died of severe infection caused by myelosuppression after chemotherapy, one patient died within 3 months after chemotherapy; two patients died of progression at 4 and 7 months after chemotherapy. A total of 3 patients achieved complete remission (CR) after chemotherapy, and 1 patient underwent allogeneic hematopoietic stem cell transplantation without disease progression or recurrence.

CONCLUSION

PLL is a rare lymphoid malignancy with an extremely poor prognosis, which tends to occur in the elderly, and the clinical manifestations of PLL lack specificity. Chemotherapy combined with targeted drugs or epigenetic drugs may benefit PLL patients. Hematopoietic stem cell transplantation should be performed after CR is obtained to improve the prognosis to the greatest extent.

T-Cell Prolymphocytic Leukemia: Diagnosis, Pathogenesis, and Treatment

T-cell prolymphocytic leukemia (T-PLL) is a rare and aggressive neoplasm of mature T-cells. Most patients with T-PLL present with lymphocytosis, anemia, thrombocytopenia, and hepatosplenomegaly. Correct identification of T-PLL is essential because treatment for this disease is distinct from that of other T-cell neoplasms. In 2019, the T-PLL International Study Group (TPLL-ISG) established criteria for the diagnosis, staging, and assessment of response to treatment of T-PLL with the goal of harmonizing research efforts and supporting clinical decision-making. T-PLL pathogenesis is commonly driven by T-cell leukemia 1 (TCL1) overexpression and ATM loss, genetic alterations that are incorporated into the TPLL-ISG diagnostic criteria. The cooperativity between TCL1 family members and ATM is seemingly unique to T-PLL across the spectrum of T-cell neoplasms. The role of the T-cell receptor, its downstream kinases, and JAK/STAT signaling are also emerging themes in disease pathogenesis and have obvious therapeutic implications. Despite improved understanding of disease pathogenesis, alemtuzumab remains the frontline therapy in the treatment of naïve patients with indications for treatment given its high response rate. Unfortunately, the responses achieved are rarely durable, and the majority of patients are not candidates for consolidation with hematopoietic stem cell transplantation. Improved understanding of T-PLL pathogenesis has unveiled novel therapeutic vulnerabilities that may change the natural history of this lymphoproliferative neoplasm and will be the focus of this concise review.

The miR-141/200c-STAT4 Axis Contributes to Leukemogenesis by Enhancing Cell Proliferation in T-PLL

T-prolymphocytic leukemia (T-PLL) is a rare and mature T-cell malignancy with characteristic chemotherapy-refractory behavior and a poor prognosis. Molecular concepts of disease development have been restricted to protein-coding genes. Recent global microRNA (miR) expression profiles revealed miR-141-3p and miR-200c-3p (miR-141/200c) as two of the highest differentially expressed miRs in T-PLL cells versus healthy donor-derived T cells. Furthermore, miR-141/200c expression separates T-PLL cases into two subgroups with high and low expression, respectively. Evaluating the potential pro-oncogenic function of miR-141/200c deregulation, we discovered accelerated proliferation and reduced stress-induced cell death induction upon stable miR-141/200c overexpression in mature T-cell leukemia/lymphoma lines. We further characterized a miR-141/200c-specific transcriptome involving the altered expression of genes associated with enhanced cell cycle transition, impaired DNA damage responses, and augmented survival signaling pathways. Among those genes, we identified STAT4 as a potential miR-141/200c target. Low STAT4 expression (in the absence of miR-141/200c upregulation) was associated with an immature phenotype of primary T-PLL cells as well as with a shortened overall survival of T-PLL patients. Overall, we demonstrate an aberrant miR-141/200c-STAT4 axis, showing for the first time the potential pathogenetic implications of a miR cluster, as well as of STAT4, in the leukemogenesis of this orphan disease.

An update on genetic aberrations in T-cell neoplasms

T-cell neoplasms are a highly heterogeneous group of leukaemias and lymphomas that represent 10-15% of all lymphoid neoplasms. Traditionally, our understanding of T-cell leukaemias and lymphomas has lagged behind that of B-cell neoplasms, in part due to their rarity. However, recent advances in our understanding of T-cell differentiation, based on gene expression and mutation profiling and other high throughput methods, have better elucidated the pathogenetic mechanisms of T-cell leukaemias and lymphomas. In this review, we provide an overview of many of the molecular abnormalities that occur in various types of T-cell leukaemia and lymphoma. Much of this knowledge has been used to refine diagnostic criteria that has been included in the fifth edition of the World Health Organization. This knowledge is also being used to improve prognostication and identify novel therapeutic targets, and we expect this progress will continue, eventually resulting in improved outcomes for patients with T-cell leukaemias and lymphomas.

Detection of chromosomal alteration after infusion of gene-edited allogeneic CAR T cells

A chromosome 14 inversion was found in a patient who developed bone marrow aplasia following treatment with allogeneic chimeric antigen receptor (CAR) Tcells containing gene edits made with transcription activator-like effector nucleases (TALEN). TALEN editing sites were not involved at either breakpoint. Recombination signal sequences (RSSs) were found suggesting recombination-activating gene (RAG)-mediated activity. The inversion represented a dominant clone detected in the context of decreasing absolute CAR Tcell and overall lymphocyte counts. The inversion was not associated with clinical consequences and wasnot detected in the drug product administered to this patient or in any drug product used in this or other trials using the same manufacturing processes. Neither was the inversion detected in this patient at earlier time points or in any other patient enrolled in this or other trials treated with this or other product lots. This case illustrates that spontaneous, possibly RAG-mediated, recombination events unrelated to gene editing can occur in adoptive cell therapy studies, emphasizes the need for ruling out off-target gene editing sites, and illustrates that other processes, such as spontaneous V(D)J recombination, can lead to chromosomal alterations in infused cells independent of gene editing.

From the archives of MD Anderson Cancer Center: Aleukemic T-prolymphocytic leukemia, a rare presentation and review of the literature

T-prolymphocytic leukemia (T-PLL) is a rare, aggressive T-cell leukemia, and patients typically present with marked peripheral blood lymphocytosis. Approximately 15-20 % of patients may present with moderate and relative stable lymphocytosis and an indolent clinical course that can persist for a few years. However, eventually these patients go on to develop marked lymphocytosis and rapidly progressive disease. We report a 72-year-old man who presented with multicompartmental lymphadenopathy and a normal complete blood count. Excision of left and right cervical lymph nodes showed replacement of the lymph node architecture by a small T-cell neoplasm positive for CD3, CD4, CD5, CD7 and TCL-1, and negative for CD8, CD20, CD30 and ALK. Subsequent bone marrow evaluation showed minimal bone marrow involvement by a T-cell neoplasm associated with TCL1A rearrangement in 11 % of cells supporting the diagnosis of T-PLL. Despite treatment, he showed progressive lymphadenopathy while remarkably maintaining normal white blood cell counts until he eventually developed leukocytosis of 110.9 × 10³/uL 26 months later. Review of the literature identified only a single abstract reporting a patient with a similar lymphoma-like presentation and normal white blood cell count; however, that case showed significant bone marrow involvement in stark contrast to the current case. In summary, we report a highly unusual case of T-PLL can initially presenting with an aleukemic or lymphoma-like clinical picture, which can make establishing the diagnosis challenging.

Classification and challenges in the histopathological diagnosis of peripheral T-cell lymphomas, emphasis on the WHO-HAEM5 updates

Mature T-cell lymphomas represent neoplastic expansions of T-cell lymphocytes with a post-thymic derivation. Most of these tumors feature aggressive clinical behavior and challenging histopathological diagnosis and classification. Novel findings in the genomic landscape of T-cell lymphomas are helping to improve the understanding of the biology and the molecular mechanisms that underly its clinical behavior. The most recent WHO-HAEM5 classification of hematolymphoid tumors introduced novel molecular and histopathological findings that will aid in the diagnostic classification of this group of neoplasms. The current review article summarizes the most relevant diagnostic features of peripheral T-cell lymphomas with an emphasis on the updates that are incorporated at the WHO-HAEM5.

Computational gene expression analysis reveals distinct molecular subgroups of T-cell prolymphocytic leukemia

T-cell prolymphocytic leukemia (T-PLL) is a rare blood cancer with poor prognosis. Overexpression of the proto-oncogene TCL1A and missense mutations of the tumor suppressor ATM are putative main drivers of T-PLL development, but so far only little is known about the existence of T-PLL gene expression subtypes. We performed an in-depth computational reanalysis of 68 gene expression profiles of one of the largest currently existing T-PLL patient cohorts. Hierarchical clustering combined with bootstrapping revealed three robust T-PLL gene expression subgroups. Additional comparative analyses revealed similarities and differences of these subgroups at the level of individual genes, signaling and metabolic pathways, and associated gene regulatory networks. Differences were mainly reflected at the transcriptomic level, whereas gene copy number profiles of the three subgroups were much more similar to each other, except for few characteristic differences like duplications of parts of the chromosomes 7, 8, 14, and 22. At the network level, most of the 41 predicted potential major regulators showed subgroup-specific expression levels that differed at least in comparison to one other subgroup. Functional annotations suggest that these regulators contribute to differences between the subgroups by altering processes like immune responses, angiogenesis, cellular respiration, cell proliferation, apoptosis, or migration. Most of these regulators are known from other cancers and several of them have been reported in relation to leukemia (e.g. AHSP, CXCL8, CXCR2, ELANE, FFAR2, G0S2, GIMAP2, IL1RN, LCN2, MBTD1, PPP1R15A). The existence of the three revealed T-PLL subgroups was further validated by a classification of T-PLL patients from two other smaller cohorts. Overall, our study contributes to an improved stratification of T-PLL and the observed subgroup-specific molecular characteristics could help to develop urgently needed targeted treatment strategies.

The 5th edition of the World Health Organization Classification of Haematolymphoid Tumours: Lymphoid Neoplasms

We herein present an overview of the upcoming 5^th edition of the World Health Organization Classification of Haematolymphoid Tumours focussing on lymphoid neoplasms. Myeloid and histiocytic neoplasms will be presented in a separate accompanying article. Besides listing the entities of the classification, we highlight and explain changes from the revised 4^th edition. These include reorganization of entities by a hierarchical system as is adopted throughout the 5^th edition of the WHO classification of tumours of all organ systems, modification of nomenclature for some entities, revision of diagnostic criteria or subtypes, deletion of certain entities, and introduction of new entities, as well as inclusion of tumour-like lesions, mesenchymal lesions specific to lymph node and spleen, and germline predisposition syndromes associated with the lymphoid neoplasms.

Mature T-Cell leukemias: Challenges in Diagnosis

T-cell clones can frequently be identified in peripheral blood. It can be difficult to appreciate whether these are benign and transient or whether they signify a clonal disorder. We review factors that aid in understanding the relevance of T-cell clones. Conversely, obvious pathological T-cell clones can be detected in blood, but there is uncertainty in how to categorize this clonal T cell population, thus, we adopt a multidisciplinary review of the clinical features, diagnostic material and radiology before making the diagnosis. In this review we shall discuss some of these challenges faced when diagnosing mature T-cell leukemias.

T-cell prolymphocytic leukaemia associated with immune checkpoint inhibitor (pembrolizumab)

We describe the case of a man in his 60s with squamous cell carcinoma of the lung with brain metastasis treated with pembrolizumab who subsequently developed T-cell prolymphocytic leukaemia. He was transferred to our hospital with worsening dyspnoea, suspected hyperviscosity syndrome and tumour lysis syndrome. He was intubated and admitted to our critical care unit. Emergent leucapheresis was started due to worsening renal function in the setting of tumour lysis and hyperviscosity syndromes. He continued to deteriorate and required continuous renal replacement therapy. Unfortunately, he eventually died from haemodynamic decompensation. There are only a few anecdotal cases pointing at a possible association between the use of immune checkpoint inhibitors and the progression or exacerbation of secondary haematological malignancies. The poor prognosis of these haematological malignancies warrants further investigation to determine if checkpoint inhibitors increase the risk of developing or propagating these potentially fatal diseases.