Characteristics, outcomes, prognostic factors and treatment of patients with T-cell prolymphocytic leukemia (T-PLL)

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.

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.

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.

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.

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.

Leukemia Cutis-The Current View on Pathogenesis, Diagnosis, and Treatment

Leukemia cutis (LC) is defined as the leukemic infiltration of the epidermis, the dermis, and the subcutaneous tissue. Leukemia cutis may follow or occur simultaneously with the diagnosis of systemic leukemia. However, cutaneous lesions are occasionally diagnosed as the primary manifestation of leukemia. Leukemic skin infiltrations demonstrate considerable variation regarding a number of changes, distribution, and morphology. The highest incidence of LC is observed in chronic lymphocytic leukemia, monocytic and myelomonocytic acute myeloid leukemia, and T-cell lineage leukemia. Although the pathogenic mechanism of the invasion of leukemic cells into the skin is not well understood, chemokine receptors and adhesion molecules as well as the genetic characteristics of leukemia are thought to play a role. Leukemic skin lesions may be localized or disseminated and may occur alone or in combination on any site of the skin, most frequently in the trunk and extremities. The most common clinical presentations of leukemia cutis are papules, nodules, macules, plaques, and ulcers. In most patients, the complete or partial resolution of cutaneous infiltrations occurs simultaneously with hematologic remission. However, in patients with resistant disease or recurrent skin infiltration, local radiotherapy can be used. This review presents recent data on the pathogenesis, diagnosis, and treatment of leukemic skin involvement in different types of leukemia.

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.

Chimeric Antigen Receptor Based Cellular Therapy for Treatment Of T-Cell Malignancies

T-cell malignancies can be divided into precursor (T-acute lymphoblastic leukemia/lymphoblastic lymphoma, T-ALL/LBL) and mature T-cell neoplasms, which are comprised of 28 different entities. Most of these malignancies are aggressive with rather poor prognosis. Prognosis of relapsed/refractory (R/R) disease is especially dismal, with an expected survival only several months after progression. Targeted therapies, such as antiCD30 immunotoxin brentuximab vedotin, antiCD38 antibody daratumumab, and anti-CCR4 antibody mogamulizumab are effective only in subsets of patients with T-cell neoplasms. T-cells equipped with chimeric antigen receptor (CAR-Ts) are routinely used for treatment of R/R B-cell malignancies, however, there are specific obstacles for their use in T-cell leukemias and lymphomas which are fratricide killing, risk of transfection of malignant cells, and T-cell aplasia. The solution for these problems relies on target antigen selection, CRISPR/Cas9 or TALEN gene editing, posttranslational regulation of CAR-T surface antigen expression, and safety switches. Structural chromosomal changes and global changes in gene expression were observed with gene-edited products. We identified 49 studies of CAR-based therapies registered on www.clinicaltrials.gov. Most of them target CD30 or CD7 antigen. Results are available only for a minority of these studies. In general, clinical responses are above 50% but reported follow-up is very short. Specific toxicities of CAR-based therapies, namely cytokine release syndrome (CRS), seem to be connected with the antigen of interest and source of cells for manufacturing. CRS is more frequent in antiCD7 CAR-T cells than in antiCD30 cells, but it is mild in most patients. More severe CRS was observed after gene-edited allogeneic CAR-T cells. Immune effector cell associated neurotoxicity (ICANS) was mild and infrequent. Graft-versus-host disease (GvHD) after allogeneic CAR-T cells from previous hematopoietic stem cell donor was also observed. Most frequent toxicities, similarly to antiCD19 CAR-T cells, are cytopenias. CAR-based cellular therapy seems feasible and effective for T-cell malignancies, however, the optimal design of CAR-based products is still unknown and long-term follow-up is needed for evaluation of their true potential.

MDS/MPN-Unclassifiable with t(X;17)(q28;q21) and KANSL1-MTCP1/CMC4 Fusion Gene

Myelodysplastic/myeloproliferative neoplasm, unclassifiable (MDS/MPN-U) is a poorly characterized entity among overlap myeloid syndromes. Recent studies have shown heterogeneous mutational profiles in this group being able to subclassify them into entities closely related to the more well-established disorders under the umbrella term of the MDS/MPN group. Recurrent cytogenetic alterations are, nonetheless, rare in MDS/MPN-U. Here, for the first time, we report a case of MDS/MPN-U with a t(X;17)(q28;q21) chromosomal rearrangement leading to the KANSL1-MTCP1 fusion gene.

Outcomes of Allogeneic Hematopoietic Cell Transplantation in T-cell Prolymphocytic Leukemia: A Contemporary Analysis from the Center for International Blood and Marrow Transplant Research

T cell prolymphocytic leukemia (T-PLL) is a rare, aggressive malignancy with limited treatment options and poor long-term survival. Previous studies of allogeneic hematopoietic cell transplantation (alloHCT) for T-PLL are limited by small numbers, and descriptions of patient and transplantation characteristics and outcomes after alloHCT are sparse. In this study, we evaluated outcomes of alloHCT in patients with T-PLL and attempted to identify predictors of post-transplantation relapse and survival. We conducted an analysis of data using the Center for International Blood and Marrow Transplant Research database on 266 patients with T-PLL who underwent alloHCT between 2008 and 2018. The 4-year rates of overall survival (OS), disease-free survival (DFS), relapse, and treatment-related mortality (TRM) were 30.0% (95% confidence interval [CI], 23.8% to 36.5%), 25.7% (95% CI, 20% to 32%), 41.9% (95% CI, 35.5% to 48.4%), and 32.4% (95% CI, 26.4% to 38.6%), respectively. In multivariable analyses, 3 variables were associated with inferior OS: receipt of a myeloablative conditioning (MAC) regimen (hazard ratio [HR], 2.18; P < .0001), age >60 years (HR, 1.61; P = .0053), and suboptimal performance status, defined by Karnofsky Performance Status (KPS) <90 (HR, 1.53; P = .0073). Receipt of an MAC regimen also was associated with increased TRM (HR, 3.31; P < .0001), an elevated cumulative incidence of grade II-IV acute graft-versus-host disease (HR, 2.94; P = .0011), and inferior DFS (HR, 1.86; P = .0004). Conditioning intensity was not associated with relapse; however, stable disease/progression was correlated with increased risk of relapse (HR, 2.13; P = .0072). Both in vivo T cell depletion (TCD) as part of conditioning and KPS <90 were associated with worse TRM and inferior DFS. Receipt of total body irradiation had no significant effect on OS, DFS, or TRM. Our data show that reduced-intensity conditioning without in vivo TCD (ie, without antithymocyte globulin or alemtuzumab) before alloHCT was associated with long-term DFS in patients with T-PLL who were age ≤60 years or who had a KPS >90 or chemosensitive disease.

Molecular characterization of Novel ATM fusions in chronic lymphocytic leukemia and T-cell prolymphocytic leukemia

ATM deletions and/or mutations are recurrent in lymphoid neoplasms while rearrangements are rare. In this study, we used mate pair sequencing (MPseq) technology to characterize two novel ATM rearrangements in one patient with chronic lymphocytic leukemia (CLL) and one patient with T-prolymphocytic leukemia (T-PLL). Both patients showed chromosome 11q22 aberrations encompassing ATM by conventional karyotype and fluorescence in situ hybridization: isolated t(11;13)(q22;q14) in CLL and a complex karyotype with apparent 11q deletion and unbalanced der(14)t(11;14)(q22;p11.2) in T-PLL. MPseq identified ATM-LINC00371 fusion in CLL and ATM-USP28 in T-PLL, both of which led to ATM inactivation, confirmed by loss of immunohistochemical protein expression. Next-generation sequencing mutation analysis detected concurrent ATM mutation(s) CLL patient, while T-PLL lacked ATM mutation. ATM rearrangements, not apparently detectable using standard laboratory technologies, represent another mechanism of loss-of-function. Recent high-throughput technologies such as MPseq can uncover novel pathogenic gene fusions and resolve complex chromosomal rearrangements in hematologic malignancies.

An aggressive CD4- CD8- T-cell neoplasm in young English bulldogs

T-cell leukemia/lymphoma accounts for roughly 30% of all types of lymphoproliferative neoplasia in dogs. Two forms of T-cell lymphoma (T-zone and peripheral T-cell lymphoma) exhibit breed-specific predilections. During the course of routine immunophenotyping, we observed a breed-specific presentation of a unique form of T-cell leukaemia in young English bulldogs. To describe the clinical presentation and outcome of a novel T-cell leukaemia in English bulldogs and determine the frequency of this neoplasm in other breeds. The Clinical Hematopathology database, containing immunophenotyping data from peripheral blood of nearly 11 900 dogs, was queried for the phenotype observed in young English bulldogs: CD45⁺ CD4^- CD8^- CD5⁺ CD3⁺ class II major histocompatibility complex (MHC)-low T-cell leukaemia. Clinical presentation, treatment, and survival data were collected for a subset of cases. Fifty-five English bulldog cases and 64 cases of other breeds were identified. No other breed was represented by >5 cases. Complete medical records were obtained for 50 bulldogs. Median age at diagnosis was 3 years and 76% of cases were male. Median lymphocyte count was 44 286 lymphocytes/μl (range, 1800-317 684/μl) and lymphocytes were described as small to intermediate-sized. Many dogs were thrombocytopenic and had liver and spleen involvement, but not lymphadenopathy. Bulldogs that received multi-agent chemotherapy had longer median survival times (83 days) compared to dogs that received no treatment (6 days) or less aggressive therapy (15 days) (p = .001). Non-bulldogs had similar outcomes. CD4^- CD8^- class II MHC-low T-cell leukaemia has an aggressive clinical course and predilection for young English bulldogs. Breed-specific presentation suggests an underlying genetic cause.

[Simultaneous determination of pentostatin and 2'-amino-2'-deoxyadenosine in fermentation broth by high performance liquid chromatography-tandem mass spectrometry]

An analytical method was established for the simultaneously determination the pentostatin and 2'-amino-2'-deoxyadenosine contents in fermentation broth by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). After high-speed centrifugation, aqueous solution dilution, vortex shock, and microfiltration, the fermentation broth samples were analyzed by HPLC-MS/MS. The samples were separated on a Waters Atlantis® T3 column (100 mm×2.1 mm, 5 μm) using a gradient elution program with 10 mmol/L ammonium formate (containing 0.1% formic acid) and methanol (containing 0.02% formic acid) as the mobile phases. Moreover, a chromatographic protection column (5 mm×2.1 mm, 5 μm) was added to preserve the column efficiency. The flow rate, column temperature, and injection volume were set at 0.3 mL/min, 25 ℃, and 10 μL, respectively. Qualitative and quantitative analyses of the target compounds were performed using an ESI+ source. MS parameters such as the collision energies and tube lens offsets of pentostatin and 2'-amino-2'-deoxyadenosine were optimized. The quantitative ion pairs of pentostatin and 2'-amino-2'-deoxyadenosine were m/z 269.17>153.20 and m/z 267.00>136.10, respectively; the corresponding collision energies were 11 V and 18 V. The external standard method was used for quantitative analysis. The established method was verified rigorously in terms of the linear range, limit of detection, limit of quantification, recovery rate, and precision. Pentostatin and 2'-amino-2'-deoxyadenosine showed good linear relationships in the range of 1.0-250 μg/L. The correlation coefficients ranged from 0.9969 to 0.9996, and the relative standard deviations (RSDs) ranged from 6.51% to 8.35% (n=8). This result indicated good accuracy and exactitude in the detection of the pentostatin and 2'-amino-2'-deoxyadenosine. The recoveries (n=6) at three spiked levels (1.0, 5.0, and 25 μg/L) were in the ranges of 97.94%-104.46% and 89.96%-107.21% for the pentostatin and 2'-amino-2'-deoxyadenosine, respectively; the corresponding RSDs were in the ranges of 3.74%-4.88% and 4.81%-13.29%. The limits of detection (LODs, S/N≥3) and limits of quantification (LOQs, S/N≥10) of the 2'-amino-2'-deoxyadenosine and pentostatin in the fermentation broth were 0.003-0.060 μg/L and 0.010-0.200 μg/L, respectively. The validated experimental method was used for the detection of actual samples, viz. the stored multiple pentostatin-producing mutagenic strains in our laboratory. The HPLC-MS/MS method for the determination of the pentostatin and 2'-amino-2'-deoxyadenosine in fermentation broth offered the advantages of small sampling volume, strong maneuverability, good stability, and high sensitivity. Compared with previously published methods, this systematically established and optimized method significantly reduced the detection time, and matrix effects were well suppressed. Moreover, the peak shape and stability of the target compounds were greatly improved. This method provides a methodological basis and meaningful reference for the detection of the pentostatin and 2'-amino-2'-deoxyadenosine in fermentation broth.

Cutaneous involvement by T-cell prolymphocytic leukemia presenting as livedoid vasculopathy

T-cell prolymphocytic leukemia (T-PLL) is a rare, aggressive neoplasm derived from post-thymic T-cells. Patients are typically middle aged with a slight male predominance who present with a high white blood cell count, hepatosplenomegaly, lymphadenopathy, and other symptoms typically associated with leukemia. Although cutaneous involvement has been reported in up to 30% of cases of T-PLL, to our knowledge, none have presented with a presentation resembling livedoid vasculopathy. In the correct clinical context, an underlying hematolymphoid neoplasm should be included in the differential diagnosis of a patient presenting with livedoid vasculopathy.

T-cell Prolymphocytic Leukemia, Cerebriform Variant

T-cell prolymphocytic leukemia (T-PLL) is a very rare and aggressive lymphoproliferative disorder. We present a 70-year-old man with complaints of fatigue, low urinary output, and peripheral edema for one month. Objectively, he presented diminished respiratory sounds bilaterally and peripheral edema. Analytical study revealed mild anemia and mild lymphomonocytosis, acute kidney injury, and urinalysis with proteins, leukocytes, erythrocytes, and cylinders. Chest radiography was consistent with pleural effusion. Subsequent study showed new onset of thrombocytopenia with a progressive increase of lymphocytosis, in association with inguinal adenopathies and splenomegaly. Immunophenotypic study of peripheral blood and lymph node biopsy were compatible with the diagnosis of T-PLL. Negative serology for human T-cell lymphotropic virus type 1 (HTLV-1) excluded adult T-cell leukemia. Progressive changes in the peripheral blood smear were seen, finally showing the presence of lymphocytes with a cerebriform nucleus, revealing this variant. There was a rapid catastrophic progression, spontaneous tumor lysis syndrome, and death.

T-Cell Prolymphocytic Leukemia: An Overview of Current and Future Approaches

T-cell prolymphocytic leukemia (T-PLL) is a rare mature T-cell hematologic neoplasm with a very poor prognosis and limited treatment options to date. Single-agent alemtuzumab remains the first line of therapy for the treatment-naive and relapsed/refractory patients. Prospective clinical trials are difficult to conduct given that these patients have a short life expectancy after the initial diagnosis. As a result, researchers are implementing the use of targeted therapies in vitro and ex vivo followed by in vivo trials on a small subset of patients which are reviewed here. Newer approaches in the treatment of T-PLL are developing based on recognizing the cytogenetic phenotype of each patient and targeting the identified defective genes that are usually involved in the cell cycle regulation such as protooncogenes, tumor suppressors, and deoxyribonucleic acid (DNA) repair genes. These could potentially redirect the management in the near future and improve the overall survival (OS) and the progression-free survival (PFS) for these patients. 

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.

Micro-RNA networks in T-cell prolymphocytic leukemia reflect T-cell activation and shape DNA damage response and survival pathways

T-cell prolymphocytic leukemia (T-PLL) is a poor-prognostic mature T-cell malignancy. It typically presents with exponentially rising lymphocyte counts, splenomegaly, and bone marrow infiltration. Effective treatment options are scarce and a better understanding of TPLL’s pathogenesis is desirable. Activation of the TCL1 proto-oncogene and loss-of-function perturbations of the tumor suppressor ATM are TPLL’s genomic hallmarks. The leukemic cell reveals a phenotype of active T-cell receptor (TCR) signaling and aberrant DNA damage responses. Regulatory networks based on the profile of microRNA (miR) have not been described for T-PLL. In a combined approach of small-RNA and transcriptome sequencing in 46 clinically and moleculary well-characterized T-PLL, we identified a global T-PLL-specific miR expression profile that involves 34 significantly deregulated miR species. This pattern strikingly resembled miR-ome signatures of TCR-activated T cells. By integrating these T-PLL miR profiles with transcriptome data, we uncovered regulatory networks associated with cell survival signaling and DNA damage response pathways. Despite a miR-ome that discerned leukemic from normal T cells, there were also robust subsets of T-PLL defined by a small set of specific miR. Most prominently, miR-141 and the miR- 200c-cluster separated cases into two major subgroups. Furthermore, increased expression of miR-223-3p as well as reduced expression of miR-21 and the miR-29 cluster were associated with more activated Tcell phenotypes and more aggressive disease presentations. Based on the implicated pathobiological role of these miR deregulations, targeting strategies around their effectors appear worth pursuing. We also established a combinatorial miR-based overall survival score for T-PLL (miROS-T-PLL), that might improve current clinical stratifications.

Leukocyte immunoglobulin-like receptor subfamily B member 1 potentially acts as a diagnostic and prognostic target in certain subtypes of adenocarcinoma

BACKGROUND

Leukocyte immunoglobulin (Ig)-like receptor subfamily B member 1 (LILRB1) involves in the occurrence and development of various tumors through transmitting immune inhibitory signals. However, the regulatory mechanism of LILRB1 underlying the disease progression of adenocarcinoma remains vague. This study is aimed to disclose the expression pattern of LILRB1 on adenocarcinoma and its indicative roles on the diagnosis and prognosis of adenocarcinoma patients.

METHODS

LILRB1 level in microarray was measured using immunohistochemistry (IHC) staining. Expression analysis of LILRB1 gene were based on the Gene Expression Profiling Interactive Analysis 2.0 (GEPIA2) and Oncomine databases. Survival and correlation analyses were analyzed using The Cancer Genome Atlas (TCGA) database (Breastinvasivecarcinoma, TCGA-BRCA).

RESULTS

The IHC results showed that the number of LILRB1-positive cells were robustly elevated in some common subtypes of adenocarcinoma including thyroid gland papillary carcinoma, gastric mixed adenocarcinoma, colon and rectal mucinous adenocarcinoma, pancreatic ductal adenocarcinoma and invasive ductal breast carcinoma compared to their corresponding para-carcinoma. Although the enhancement of LILRB1 expression was only observed in pancreaticadenocarcinoma (PAAD) by using GEPIA2, its expression presented a significant increase in the above subtypes of adenocarcinoma by analyzing using Oncomine database. Besides, there had a significant positive association between LILRB1 expression status and pathological stages, and a negative association between LILRB1 status and Overall Survival (OS) probability in the above certain subtypes of adenocarcinoma.

CONCLUSION

LILRB1 is abnormally upregulated in certain subtypes of adenocarcinoma. Patients with low LILRB1 possibly portend a good prognosis in adenocarcinoma. These findings imply that LILRB1 may act as a diagnostic and prognostic target in some subtypes of adenocarcinoma.

Patterns of Late Relapse after Allogeneic Hematopoietic Stem Cell Transplantation in Patients with T-Cell Prolymphocytic Leukemia

Initial treatment with the monoclonal anti-CD52 antibody alemtuzumab induces responses in the majority of patients with T-cell prolymphocytic leukemia (T-PLL). In eligible patients, allogeneic hematopoietic stem cell transplantation (allo-HSCT) is an option to consolidate hematological remissions. Here, we report our experience with 10 patients who received allo-HSCT against T-PLL. Notably, 3 patients with complete remission at transplantation and durable full-donor chimerism relapsed at months 12, 59, and 84 after transplantation, respectively. This relapse was associated with rapid progressive leukemia in 1 patient and extralymphatic lymphoma growth in the other 2. Despite CD52 positivity at relapse, alemtuzumab retreatment, donor lymphocyte infusions, and/or chemotherapy including salvage therapy, allo-HSCT yielded a transient partial response, only. Alemtuzumab induction and consolidative allo-HSCT enabled prolonged disease-free survival in these patients but failed to procure cure.

Current understandings on T-cell prolymphocytic leukemia and its association with TCL1 proto-oncogene

T-cell prolymphocytic leukemia (T-PLL) is a rare mature T cell leukemia with aggressive clinical course, poor response to conventional therapies and high mortality rates. Classical cytogenetics and various genetic techniques have observed complex karyotypes and associated genes involved in the molecular pathogenesis of T-PLL, among which the proto-oncogene T-cell leukemia/lymphoma 1 (TCL1) as a hallmark of malignancy is hyper-activated and abnormally expressed in many T-PLL cases. Progress has been made to identify the presence of chromosomal rearrangements and subsequent changes in key molecular pathways typically involving Akt, which may hint cytogenetic mechanisms underlying the pathogenesis of T-PLL and indicate new treatment targets. In this article, we describe current insights of T-PLL with an emphasis on the potential role of TCL1 gene disorders and TCL1-Akt interactions in cell transformation and disease progression, followed by discussion on current treatment options and novel therapeutic approaches based on cytogenetics, which still remains to be explored for the effective management of T-PLL and other TCL1-driven hematological malignancies.

Bilateral tonsillar infiltration of T-cell prolymphocytic leukemia

Tonsillar lymphoma usually presents as unilateral or bilateral infiltration of diffuse large B-cell lymphomas. We report a case of a 79-year-old man with near-complete obstruction of the upper airways due to T-cell prolymphocytic leukemia cells. Surgical resection was safely performed to reduce burden of disease.

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

T-cell prolymphocytic leukemia (T-PLL) is a rare, mature T-cell neoplasm with a heterogeneous clinical course. With the advent of novel treatment options that will potentially change the management of patients with T-PLL, it has become necessary to produce consensus guidelines for the design and conduct of clinical trials. The T-PLL International Study group (TPLL-ISG) set out to define standardized criteria for diagnosis, treatment indication, and evaluation of response. These criteria will facilitate comparison of results from clinical trials in T-PLL, and will thus support clinical decision making, as well as the approval of new therapeutics by healthcare authorities.

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.

The MHC class I-LILRB1 signalling axis as a promising target in cancer therapy

Immune checkpoint inhibitors are among the newest, cutting-edge methods for the treatment of cancer. Currently, they primarily influence T cell adaptive immunotherapy targeting the PD-1/PD-L1 and CTLA-4/B7 signalling pathways. These inhibitors fight cancer by reactivating the patient's own adaptive immune system, with good results in many cancers. With the discovery of the "Don't Eat Me" molecule, CD47, antibody-based drugs that target the macrophage-related innate immunosuppressive signalling pathway, CD47-SIRPα, have been developed and have achieved stunning results in the laboratory and the clinic, but there remain unexplained instances of tumour immune escape. While investigating the immunological tolerance of cancer to anti-CD47 antibodies, a second "Don't Eat Me" molecule on tumour cells, beta 2 microglobulin (β2m), a component of MHC class I, was described. Some tumour cells reduce their surface expression of MHC class I to escape T cell recognition. However, other tumour cells highly express β2m complexed with the MHC class I heavy chain to send a "Don't Eat Me" signal by binding to leucocyte immunoglobulin-like receptor family B, member 1 (LILRB1) on macrophages, leading to a loss of immune surveillance. Investigating the mechanisms underlying this immunosuppressive MHC class I-LILRB1 signalling axis in tumour-associated macrophages will be useful in developing therapies to restore macrophage function and control MHC class I signalling in patient tumours. The goal is to promote adaptive immunity while suppressing the innate immune response to tumours. This work will identify new therapeutic targets for the development of pharmaceutical-based tumour immunotherapy.

B and T cell prolymphocytic leukaemia

Prolymphocytic leukaemias B-PLL and T-PLL are rare disorders, typically with an aggressive clinical course and poor prognosis. Combining morphology, immunophenotyping, cytogenetic and molecular diagnostics reliably separates B-PLL and T-PLL from one another and other disorders. In T-PLL discovery of frequent mutations in the JAK-STAT pathway have increased understanding of disease pathogenesis. Alemtuzumab (anti-CD52) produces excellent response rates but long-term remissions are only achieved in a minority following consolidation with allogeneic stem cell transplant. Molecular abnormalities in B-PLL are less understood. Disruption of TP53 is a key finding, conveying chemotherapy resistance requiring novel therapies such as B-cell receptor inhibitors (BCRi). Both conditions require improved pathobiological knowledge to identify new treatment targets and guide therapy with novel pathway inhibitors.

Composite Chronic Lymphocytic Leukemia/Small Lymphocytic Lymphoma and T-Prolymphocytic Leukemia Presenting with Lymphocytosis, Skin Lesions, and Generalized Lymphadenopathy

Chronic lymphocytic leukemia (CLL) is the most common type of leukemia in Western countries with an incidence of 3-5 cases per 100,000 persons. Most patients follow an indolent clinical course with eventual progression and need for therapy. In contrast, T-prolymphocytic leukemia (T-PLL) is a rare type of T-cell leukemia with most patients having an aggressive clinical course and a dismal prognosis. Therapies are limited for T-PLL patients and there is a high relapse rate. Morphologically, the cells of CLL and T-PLL can show overlapping features. Here, we report the case of a 61-year-old man who presented with a clinically indolent CLL and T-PLL, initially diagnosed solely and followed as CLL, despite the presence of an associated but unrecognized aberrant T-cell population in blood. After 2 years, the T-PLL component became more apparent with cutaneous and hematologic manifestations and the diagnosis was confirmed by immunophenotypic and cytogenetic analysis. Fluorescence in situ hybridization demonstrated an ATM deletion in both CLL and T-PLL components. Retrospective testing demonstrated that composite CLL and T-PLL were both present in skin and lymph nodes as well as in blood and bone marrow since initial presentation. This case is also unique because it highlights that a subset of T-PLL patients can present with clinically indolent disease. The concomitant detection of ATM mutation in CLL and T-PLL components raises the possibility of a common pathogenic mechanism.

EBMT prospective observational study on allogeneic hematopoietic stem cell transplantation in T-prolymphocytic leukemia (T-PLL)

Preliminary data suggest that allogeneic stem cell transplantation (allo-SCT) may be effective in T-prolymphocytic leukemia (T-PLL). The purpose of the present observational study was to assess the outcome of allo-SCT in patients aged 65 years or younger with a centrally confirmed diagnosis of T-PLL. Patients were consecutively registered with the EBMT at the time of transplantation and followed by routine EBMT monitoring but with an extended dataset. Between 2007 and 2012, 37 evaluable patients (median age 56 years) were accrued. Pre-treatment contained alemtuzumab in 95% of patients. Sixty-two percent were in complete remission (CR) at the time of allo-SCT. Conditioning contained total body irradiation with 6 Gy or more (TBI6) in 30% of patients. With a median follow-up of 50 months, the 4-year non-relapse mortality, relapse incidence, progression-free (PFS) and overall survival were 32, 38, 30 and 42%, respectively. By univariate analysis, TBI6 in the conditioning was the only significant predictor for a low relapse risk, and an interval between diagnosis and allo-SCT of more than 12 months was associated with a lower NRM. This study confirms for the first time prospectively that allo-SCT can provide long-term disease control in a sizable albeit limited proportion of patients with T-PLL.

Clinically silent indolent T-cell leukemia

The clinically silent, symptom‐free T‐cell prolymphocytic leukemia case that we report here confirms the major interest of the analysis of the blood smear as usual care of any emergent lymphocytosis. It also brings out the issue of the monitoring and follow‐up of this uncommon presentation.