Epigenetic alteration contributes to the transcriptional reprogramming in T-cell prolymphocytic leukemia.

T cell prolymphocytic leukemia (T-PLL) is a rare disease with aggressive clinical course. Cytogenetic analysis, whole-exome and whole-genome sequencing have identified primary structural alterations in T-PLL, including inversion, translocation and copy number variation. Recurrent somatic mutations were also identified in genes encoding chromatin regulators and those in the JAK-STAT signaling pathway. Epigenetic alterations are the hallmark of many cancers. However, genome-wide epigenomic profiles have not been reported in T-PLL, limiting the mechanistic study of its carcinogenesis. We hypothesize epigenetic mechanisms also play a key role in T-PLL pathogenesis. To systematically test this hypothesis, we generated genome-wide maps of regulatory regions using H3K4me3 and H3K27ac ChIP-seq, as well as RNA-seq data in both T-PLL patients and healthy individuals. We found that genes down-regulated in T-PLL are mainly associated with defense response, immune system or adaptive immune response, while up-regulated genes are enriched in developmental process, as well as WNT signaling pathway with crucial roles in cell fate decision. In particular, our analysis revealed a global alteration of regulatory landscape in T-PLL, with differential peaks highly enriched for binding motifs of immune related transcription factors, supporting the epigenetic regulation of oncogenes and genes involved in DNA damage response and T-cell activation. Together, our work reveals a causal role of epigenetic dysregulation in T-PLL.

Cutaneous Presentation of T-Cell Prolymphocytic Leukemia Mimicking Dermatomyositis.

ABSTRACT: T-cell prolymphocytic leukemia (TPLL) is a rare form of leukemia by T lymphocytes at a post-thymic intermediate stage of development with an α/ß immunophenotype. Facial involvement is common in TPLL and displays significant heterogeneity of the lesions' description and location. TPLL also contains a wide array of histology findings, cell cytology, and molecular studies. Here, we describe a TPLL patient who presented with an ill-defined erythematous patch involving the right axilla progressing to the left axilla, upper back, and face that resembled dermatomyositis. The diagnosis of TPLL was established using flow cytometry of bone marrow and peripheral blood, and histopathology of the involved skin. Dermatologists should be aware of these unique features.

Immunomodulatory effects of pevonedistat, a NEDD8-activating enzyme inhibitor, in chronic lymphocytic leukemia-derived T cells.

Novel targeted agents used in therapy of lymphoid malignancies, such as inhibitors of B-cell receptor-associated kinases, are recognized to have complex immune-mediated effects. NEDD8-activating enzyme (NAE) has been identified as a tractable target in chronic lymphocytic leukemia (CLL) and non-Hodgkin lymphoma. We and others have shown that pevonedistat (TAK-924), a small-molecule inhibitor of NAE, abrogates NF-κB signaling in malignant B cells. However, NF-κB pathway activity is indispensable in immune response, and T-cell function is altered in patients with CLL. Using T cells derived from patients with CLL, we demonstrate that although targeting NAE results in markedly differential expression of NF-κB-regulated genes and downregulation of interleukin (IL)-2 signaling during T-cell activation, T cells evade apoptosis. Meanwhile, NAE inhibition favorably modulates polarization of T cells in vitro, with decreased Treg differentiation and a shift toward TH1 phenotype, accompanied by increased interferon-γ production. These findings were recapitulated in vivo in immunocompetent mouse models. T cells exposed to pevonedistat in washout experiments, informed by its human pharmacokinetic profile, recover NAE activity, and maintain their response to T-cell receptor stimulation and cytotoxic potential. Our data shed light on the potential immune implications of targeting neddylation in CLL and lymphoid malignancies.

Noncanonical effector functions of the T-memory-like T-PLL cell are shaped by cooperative TCL1A and TCR signaling.

T-cell prolymphocytic leukemia (T-PLL) is a poor-prognostic neoplasm. Differentiation stage and immune-effector functions of the underlying tumor cell are insufficiently characterized. Constitutive activation of the T-cell leukemia 1A (TCL1A) oncogene distinguishes the (pre)leukemic cell from regular postthymic T cells. We assessed activation-response patterns of the T-PLL lymphocyte and interrogated the modulatory impact by TCL1A. Immunophenotypic and gene expression profiles revealed a unique spectrum of memory-type differentiation of T-PLL with predominant central-memory stages and frequent noncanonical patterns. Virtually all T-PLL expressed a T-cell receptor (TCR) and/or CD28-coreceptor without overrepresentation of specific TCR clonotypes. The highly activated leukemic cells also revealed losses of negative-regulatory TCR coreceptors (eg, CTLA4). TCR stimulation of T-PLL cells evoked higher-than-normal cell-cycle transition and profiles of cytokine release that resembled those of normal memory T cells. More activated phenotypes and higher TCL1A correlated with inferior clinical outcomes. TCL1A was linked to the marked resistance of T-PLL to activation- and FAS-induced cell death. Enforced TCL1A enhanced phospho-activation of TCR kinases, second-messenger generation, and JAK/STAT or NFAT transcriptional responses. This reduced the input thresholds for IL-2 secretion in a sensitizer-like fashion. Mice of TCL1A-initiated protracted T-PLL development resembled such features. When equipped with epitope-defined TCRs or chimeric antigen receptors, these Lckpr-hTCL1Atg T cells gained a leukemogenic growth advantage in scenarios of receptor stimulation. Overall, we propose a model of T-PLL pathogenesis in which TCL1A enhances TCR signals and drives the accumulation of death-resistant memory-type cells that use amplified low-level stimulatory input, and whose loss of negative coregulators additionally maintains their activated state. Treatment rationales are provided by combined interception in TCR and survival signaling.

T-Cell Dynamics in Chronic Lymphocytic Leukemia under Different Treatment Modalities.

PURPOSE: Using next-generation sequencing (NGS), we recently documented T-cell oligoclonality in treatment-naïve chronic lymphocytic leukemia (CLL), with evidence indicating T-cell selection by restricted antigens. EXPERIMENTAL DESIGN: Here, we sought to comprehensively assess T-cell repertoire changes during treatment in relation to (i) treatment type [fludarabine-cyclophosphamide-rituximab (FCR) versus ibrutinib (IB) versus rituximab-idelalisib (R-ID)], and (ii) clinical response, by combining NGS immunoprofiling, flow cytometry, and functional bioassays. RESULTS: T-cell clonality significantly increased at (i) 3 months in the FCR and R-ID treatment groups, and (ii) over deepening clinical response in the R-ID group, with a similar trend detected in the IB group. Notably, in constrast to FCR that induced T-cell repertoire reconstitution, B-cell receptor signaling inhibitors (BcRi) preserved pretreatment clones. Extensive comparisons both within CLL as well as against T-cell receptor sequence databases showed little similarity with other entities, but instead revealed major clonotypes shared exclusively by patients with CLL, alluding to selection by conserved CLL-associated antigens. We then evaluated the functional effect of treatments on T cells and found that (i) R-ID upregulated the expression of activation markers in effector memory T cells, and (ii) both BcRi improved antitumor T-cell immune synapse formation, in marked contrast to FCR. CONCLUSIONS: Taken together, our NGS immunoprofiling data suggest that BcRi retain T-cell clones that may have developed against CLL-associated antigens. Phenotypic and immune synapse bioassays support a concurrent restoration of functionality, mostly evident for R-ID, arguably contributing to clinical response.

Advances and Perspectives in the Treatment of T-PLL.

PURPOSE OF REVIEW: T cell prolymphocytic leukemia (T-PLL) is a rare mature T cell tumor. Available treatment options in this aggressive disease are largely inefficient and patient outcomes are highly dissatisfactory. Current therapeutic strategies mainly employ the CD52-antibody alemtuzumab as the most active single agent. However, sustained remissions after sole alemtuzumab-based induction are exceptions. Responses after available second-line strategies are even less durable. More profound disease control or rare curative outcomes can currently only be expected after a consolidating allogeneic hematopoietic stem cell transplantation (allo-HSCT) in best first response. However, only 30-50% of patients are eligible for this procedure. Major advances in the molecular characterization of T-PLL during recent years have stimulated translational studies on potential vulnerabilities of the T-PLL cell. We summarize here the current state of "classical" treatments and critically appraise novel (pre)clinical strategies. RECENT FINDINGS: Alemtuzumab-induced first remissions, accomplished in ≈ 90% of patients, last at median ≈ 12 months. Series on allo-HSCT in T-PLL, although of very heterogeneous character, suggest a slight improvement in outcomes among transplanted patients within the past decade. Dual-action nucleosides such as bendamustine or cladribine show moderate clinical activity as single agents in the setting of relapsed or refractory disease. Induction of apoptosis via reactivation of p53 (e.g., by inhibitors of HDAC or MDM2) and targeting of its downstream pathways (i.e., BCL2 family antagonists, CDK inhibitors) are promising new approaches. Novel strategies also focus on inhibition of the JAK/STAT pathway with the first clinical data. Implementations of immune-checkpoint blockades or CAR-T cell therapy are at the stage of pre-clinical assessments of activity and feasibility. The recommended treatment strategy in T-PLL remains a successful induction by infusional alemtuzumab followed by a consolidating allo-HSCT in eligible patients. Nevertheless, long-term survivors after this "standard" comprise only 10-20%. The increasingly revealed molecular make-up of T-PLL and the tremendous expansion of approved targeted compounds in oncology represent a "never-before" opportunity to successfully tackle the voids in T-PLL. Approaches, e.g., those reinstating deficient cell death execution, show encouraging pre-clinical and first-in-human results in T-PLL, and urgently have to be transferred to systematic clinical testing.

CD161 Is Expressed in a Subset of T-Cell Prolymphocytic Leukemia Cases and Is Useful for Disease Follow-up.

OBJECTIVES: CD161 (NKRP1) is a lectin-like receptor present on NK cells and rare T-cell subsets. We have observed CD161 expression in some cases of T-cell prolymphocytic leukemia (T-PLL) and found it to be useful in follow-up and detection of disease after treatment. METHODS: Retrospective review of T-PLL cases with complete flow cytometry data including CD161. RESULTS: We identified 10 cases of T-PLL with flow cytometric evaluation of CD161 available. Six of these cases were positive for CD161 expression. All CD161-positive cases were positive for CD8 with variable CD4 expression, whereas all CD161-negative cases were negative for CD8. In a case with two neoplastic subsets positive and negative for CD8, only the former expressed CD161. CONCLUSIONS: These novel results suggest that CD161 is often aberrantly expressed in a defined subset of T-PLL positive for CD8. We are showing the utility of this immunophenotype in diagnosis and follow-up.

False-Positive Light Chain Clonal Restriction by Flow Cytometry in Patients Treated With Alemtuzumab: Potential Pitfalls for the Misdiagnosis of B-Cell Neoplasms.

Objectives: To increase awareness of potential diagnostic test interference associated with alemtuzumab, which is a therapeutic immunoglobulin G1 κ monoclonal antibody used in hematologic malignancies, autoimmune diseases, and transplant-related disorders. Methods: Bone marrow and blood from patients with T-cell prolymphocytic leukemia treated with alemtuzumab were evaluated by flow cytometry. Healthy donor blood was analyzed with or without in vitro treatment with alemtuzumab for comparison. Results: Immunophenotypic analysis of bone marrow collected 4 weeks after alemtuzumab treatment demonstrated artifactual surface κ light chain restriction in CD19+ B cells and CD3+ T cells. Similar findings were observed in blood from another patient in a specimen collected 3 days after alemtuzumab treatment. These findings were recapitulated in healthy donor blood incubated with alemtuzumab. Conclusions: Alemtuzumab can produce direct interference during flow cytometry analysis, resulting in false-positive evidence of light chain clonality. Clinicians and laboratorians should be cognizant of this risk to avoid misdiagnosis of B-cell neoplasms.

[Clinical and Immunophenotypic Properties of Small Cell Variant of T-cell Prolymphocytic Leukemia].

OBJECTIVE: To investigate the clinical, morphologic and immunophenotypic properties of the patients with small cell variant of T-cell prolymphocytic leukaemia(T-PLL). METHODS: Peripheral blood and bone marrow cytomorphologic and immunophenotypic examination, and T-cell receptor(TCR) gene rearrangement detection were used to verify the diagnosis for 2 patients with lymphocytosis. Two patients were treated with combined chemotherapeutic protocol based on fludarabine. RESULTS: At diagnosis of case 1, the main lymphocytes of peripheral blood smear were the small mature lymphocytes without nucleoli. The immunophenotype of the cells was CD3+CD5+CD7+CD4+CD8+TCRα/ß+. The patient achieved complete remission after treatment with combined with CTX of fludarabine. The disease relapsed at 32 months after diagnosis. The abnormal lymphocytes were medium-sized ones with a visible nucleolus. Immunophenotyping showed that the leukemic cells were predominantly CD8 positive(CD3+CD5+CD7+CD4-CD8+TCRα/ß+). Both the peripheral blood and bone marrow cells of case 2 were predominanthy the mature lymphocytes, and their immunophenotype was HLA-DR+CD7+CD5+CD4+CD3+CD2+CD56+cCD3+TCRα/ß+. The combined fludarabine therapy was ineffective. CONCLUSION: Immunophenotypical switch from CD4+CD8+ to CD4-CD8+ may be associated with a poor response to chemotherapy. CD56 expression is an independent poor prognostic factor for primary refractory disease in T-PLL and may be considered for implementing risked-adapted therapeutic strategies.

Rosacea-Like Leukemia Cutis: A Case Report.

Leukemia cutis describes the infiltration and dissemination of neoplastic leukemic cells into the epidermis, dermis, or subcutis, resulting in clinically identifiable cutaneous lesions. Depending on the type of leukemia, a wide range of clinical and histopathological findings may be encountered. This report describes a patient with a rosacea-like eruption as a unique clinical presentation of T-cell prolymphocytic leukemia.

Expression of S100 Protein in CD4-positive T-cell Lymphomas Is Often Associated With T-cell Prolymphocytic Leukemia.

S100 T-cell lymphomas are infrequent, and except 1 all have been CD4 negative. On the basis of an index case of CD4 S100 T-cell prolymphocytic leukemia (T-PLL), we studied S100 protein expression in 19 additional T-PLLs and 56 other T-cell lymphomas that are usually CD4, including 15 angioimmunoblastic T-cell lymphomas, 24 anaplastic large cell lymphomas (16 ALK and 8 ALK), 7 mycosis fungoides/Sézary syndrome, and 10 peripheral T-cell lymphoma, not otherwise specified (PTCL, NOS). Two additional S100 CD4 PTCL, NOS cases were also reviewed. Thirty percent (6/20) of T-PLLs were S100 compared with 0/56 other T-cell lymphomas with previously unstudied S100 reactivity (40 CD4, 2 CD8, 11 CD4/CD8, 3 unknown) (P=0.0007). There were no significant differences between the S100 and S100 T-PLLs with regard to the male:female ratio (2:1 vs. 1:1), age (71.6±7.7 vs. 65.4±9.3), peripheral blood lymphocyte count (67.2±116.6 vs. 101.1±159.7×10/L), or median survival (463 vs. 578 d, where known). The 2 S100 PTCL, NOS cases occurred in a 7-year-old boy and a 45-year-old woman. Both had involvement of the bone marrow and peripheral blood but were morphologically unlike T-PLL and lacked TCL1 gene rearrangement. These results demonstrate that S100 T-cell lymphomas include a subset that are CD4 and most often, but not exclusively, are T-PLL. Although having diagnostic implications, there were no documented clinical differences between the S100 and S100 T-PLLs.

A γ/δ T-cell receptor prolymphocytic leukemia and CD4-/CD8- double-negative immunophenotype in a pediatric patient.

T-cell prolymphocytic leukemia is a very rare neoplasm, peaking in the seventh decade. An extensive search failed to find any report of this malignancy in the pediatric population. The malignant cell is morphologically characterized by a high nucleocytopasmic ratio, condensed chromatin, a single nucleolus, and nongranular basophilic cytoplasm. Cells are usually positive for the α/ß and only rarely to the γ/δ T-cell receptors. Most patients follow an aggressive clinical course, only some respond to anti-CD52. We present a 6-year-old boy with T-cell prolymphocytic leukemia. The malignant cells expressed a postthymic immunophenotype (CD4/CD8) and positivity for the γ/δ T-cell receptors. The child died after 8 months despite aggressive chemotherapy, anti-CD52, and an allogeneic bone marrow transplant.

T-cell prolymphocytic leukemia frequently shows cutaneous involvement and is associated with gains of MYC, loss of ATM, and TCL1A rearrangement.

T-cell prolymphocytic leukemia (T-PLL) is a rare aggressive mature T-cell leukemia with frequent cutaneous presentation, which has not been well characterized. Among the 25 T-PLLs diagnosed between 1990 and 2013 at our institution, 32% (8/25) showed cutaneous manifestations, presenting as rash, purpura, papules, and ulcers. The skin biopsies showed leukemia cutis with perivascular and periadnexal irregular, small to medium-sized lymphoid infiltrates without epidermotropism. The lymphoid infiltrates were composed of mature CD4+ T cells expressing other T-cell antigens, and a subset (48%) showed dual CD4+/CD8+ coexpression. Higher median absolute peripheral blood lymphocyte count (43.0 vs. 13.0 k/mm; P=0.031) and elevated lactate dehydrogenase levels (P=0.00018) at the time of diagnosis were significantly associated with T-PLLs with skin involvement compared with those without. The extent of bone marrow involvement (P=0.849) and overall survival (P=0.144) was similar in the 2 groups. Fluorescence in situ hybridization or karyotype revealed frequent gains of MYC (67%; n=9), loss of ATM (64%; n=11), and TCL1A rearrangement or inversion 14q (75%; n=12). Gains of TCL1A was also seen (78%; n=9), including in some cases that had concurrent TCL1A rearrangement, whereas TP53 loss was less common (30%; n=10). No correlation was seen between the immunophenotype and morphology versus the presence or absence of skin involvement. These data suggest that cutaneous involvement by T-PLL is relatively common and often associated with significant peripheral blood involvement. The frequent MYC, ATM, and TCL1A alterations identified support that these genes are integral to the pathogenesis of T-PLL.

Progressive intracranial hypertension and cerebral hypoperfusion in a fatal case of cerebral aspergilloma.

We report a case of cerebral aspergilloma in a 25-year-old immunoincompetent man admitted to a general intensive care unit. Monitoring of intracranial pressure was instigated and revealed hour-long epochs of severe intracranial hypertension, despite a normal opening pressure, with decreases in cerebral perfusion pressure. We documented that this was associated with cerebral hypoperfusion by transcranial Doppler ultrasound. The present case illustrates that severe intracranial hypertension may evolve despite a normal opening pressure; it furthermore shows that continuous monitoring of intracranial pressure may be used to predict changes in cerebral haemodynamics in critically ill patients with neuroinfection.

T-cell prolymphocytic leukemia with extensive cardiovascular infiltrate leading to multiple myocardial infarctions and cardiac death.

Lymphocytic neoplasm involving the heart is not common and usually presents with pericardial effusion or focal myocardial infiltration. Myocardial infarctions due to leukemic infiltration of the coronary arteries are rarely reported. We present the case of a 52-year-old Guatemalan man with a one-year history of untreated T-cell prolymphocytic leukemia. He was admitted to our hospital for chemotherapy and evaluation of a pulmonary cavitary lesion by wedge resection. During sedation, the patient experienced acute respiratory failure and hypovolemic shock, from which he could not be resuscitated. Autopsy revealed that leukemic cells extensively infiltrated the aorta, myocardium, and coronary arteries. The lumina of the 3 major coronary artery branches showed 70% to 95% stenosis, with multifocal remote myocardial infarctions. Tumor cells were also detected in the lungs and other organs. The acute cardiorespiratory insufficiency secondary to leukemia-particularly the extensive infiltration of the coronary arteries and myocardium, and the multiple myocardial infarctions-eventually resulted in cardiac death.

Immunophenotypic characterization of T-cell prolymphocytic leukemia.

OBJECTIVES: To review clinical data, cytogenetic findings, and flow cytometric analysis in 20 patients with T-cell prolymphocytic leukemia (T-PLL), a rare, aggressive, mature T-cell leukemia with poor prognosis and short survival. METHODS: Using multiparameter flow cytometry with a large combination of antibodies, we summarize the immunophenotypic features of T-PLL, including unusual immunophenotypic variants, and illustrate immunophenotypic clues that may help distinguish this entity from other T-cell malignancies. RESULTS: By flow cytometry, T-PLL is characterized by a postthymic mature T-cell immunophenotype with a variety of abnormalities that usually allow distinction from other mature T-cell leukemias. CONCLUSIONS: Although definitive diagnosis of T-PLL requires a systemic approach with integration of clinical data, morphology, immunophenotype, cytogenetics/fluorescence in situ hybridization, and molecular features, our results indicate immunophenotyping by multiparameter flow cytometry greatly facilitates diagnosis and assists with subclassification of this mature T-cell leukemia.

B- and T-cell prolymphocytic leukemia: antibody approaches.

B- and T-cell subtypes of prolymphocytic leukemia (PLL) are rare, aggressive lymphoid malignancies with characteristic morphologic, immunophenotypic, cytogenetic, and molecular features. Prognosis for these patients remains poor, with short survival times and no curative therapy. The advent of mAbs has improved treatment options. In B-PLL, rituximab-based combination chemoimmunotherapy is effective in fitter patients. TP53 abnormalities are common and, as for chronic lymphocytic leukemia, these patients should generally be managed using an alemtuzumab-based therapy. Currently, the best treatment for T-PLL is IV alemtuzumab, which has resulted in very high response rates of more than 90% when given as frontline treatment and a significant improvement in survival. Consolidation of remissions with autologous or allogeneic stem cell transplantation further prolongs survival times, and the latter may offer potential cure. The role of allogeneic transplantation with nonmyeloablative conditioning needs to be explored further in both T- and B-PLL to broaden the patient eligibility for what may be a curative treatment.

A case report of T cell prolymphocytic leukemia and Kaposi sarcoma and a review of T cell prolymphocytic leukemia.

T cell prolymphocytic leukemia (T-PLL) is a rare mature T cell lymphoproliferative disease. It has been associated with an aggressive course, a poor response to conventional chemotherapy and a short median survival. Here we present a rare case of concurrent T-PLL and Kaposi sarcoma who achieved a complete hematologic and cytogenetic remission after a very short course of treatment with alemtuzumab. A review of T-PLL was done. In this review, clinical features, laboratory features and current therapeutic strategies of T-PLL are presented.