How I treat prolymphocytic leukemia

Antileukaemic rescue by dose-dense donor-lymphocyte infusions in T-PLL after allogeneic stem cell transplantation - a case report

T-Cell Prolymphocytic Leukaemia (T-PLL) is an aggressive disease with a poor prognosis and only curable by allogeneic stem cell transplantation. We describe the case of a male suffering from T-PLL. Therapy was alemtuzumab followed by an allograft from an unrelated donor. T-PLL relapsed after allogeneic stem cell transplantation. Discontinuation of immunosuppression had no effected and three increasing doses of donor lymphocytes were given within one month. The patient developed acute GvHD of the lover (grade III). GvHD was successfully treated by steroids and ruxolitinib and graft-versus-leukaemia effects induced a complete remission of T-PLL. 18,5 months after transplantation the patient is well and alive without GvHD under immunosuppression with ruxolitinib. Flow cytometry of peripheral blood was negative for residual leukemic cells.

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.

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.

An effective treatment and suspicious adverse reaction to Ibrutinib in a patient diagnosed with splenic B-cell lymphoma/leukaemia with prominent nucleoli: A first case report

RATIONALE

Splenic B-cell lymphoma/leukemia with prominent nucleoli (SBLPN) is a new classification, which is so rare that it lacks clinical data.

PATIENT CONCERNS

An increased proportion of prolymphocytes (84%) in the bone marrow smear. Whole exon sequence analysis revealed a TP53 mutation.

DIAGNOSES

Combining the clinical features with laboratory test results led to a diagnosis of SBLPN which was made according to the 5th edition of the WHO classification of hematolymphoid tumors, although the patient was diagnosed with B-PLL when guided by the 4th edition of the WHO classification.

INTERVENTIONS

The use of Ibrutinib as an effective treatment.

OUTCOMES

The patient was in complete remission after 5 months of Ibrutinib and then died of sudden aortic dissection.

LESSONS

Ibrutinib was an effective regimen for SBLPN. Aortic dissection might be considered as a suspicious adverse reaction to Ibrutinib.

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.

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.

De-Novo B-Cell Prolymphocytic Leukemia

B-cell prolymphocytic leukemia (B-PLL) is a rare B-cell neoplasm that typically presents with splenomegaly, a rising white blood cell count, and may or may not have B symptoms. The diagnosis usually requires a bone marrow biopsy and aspirate with flow cytometry and cytogenetic studies. At least 55% of the lymphocytes in the peripheral blood must be prolymphocytes to be defined as B-PLL. A thorough differential diagnosis would include mantle cell lymphoma, chronic lymphocytic leukemia (CLL) with prolymphocytes, hairy cell leukemia, and splenic marginal zone lymphoma. B-PLL is managed with regimens utilized for CLL, such as ibrutinib and rituximab but is tailored for each individual. The authors report a rare case of B-PLL in a patient with no known history of CLL. The authors discuss this entity in context of the 2017 and 2022 World Health Organization (WHO) classifications, the latter of which no longer recognizes B-PLL as a distinct entity. The authors hope that this article helps practitioners with the diagnosis and treatment of B-PLL. Perhaps with better recognition, and better documentation of histopathologic features of these rare cases going forward, it may prove to be a distinct entity again in future classifications.

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.

The role of allogeneic hematopoietic cell transplantation for chronic lymphocytic leukemia: A review

Although the use of allogeneic hematopoietic cell transplantation (HCT) for chronic lymphocytic leukemia (CLL) has declined with the development of novel targeted agents, it continues to play an important role for eligible patients with high-risk or heavily pretreated CLL who lack other treatment options. CLL is susceptible to a potent graft-versus-leukemia (GVL) effect which produces long-lasting remissions in 30-50% of transplanted patients. While allogeneic HCT is associated with significant risks of graft-versus-host disease (GVHD), infection, and non-relapse mortality (NRM), improvements in patient and donor selection, reduced intensity conditioning (RIC), GVHD prophylaxis, and supportive care have rendered this an increasingly safe and effective procedure in the current era. In this review, we discuss recent advances in allogeneic HCT for CLL, with a focus on the optimal evidence-based strategies to maximize benefit and minimize toxicity of this potentially curative cellular therapy.

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.

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.

Non-canonical function of AGO2 augments T-cell receptor signaling in T-cell prolymphocytic leukemia

T-cell prolymphocytic leukemia (T-PLL) is a chemotherapy-refractory T-cell malignancy with limited therapeutic options and a poor prognosis. Current disease concepts implicate TCL1A oncogene-mediated enhanced T-cell receptor (TCR) signaling and aberrant DNA repair as central perturbed pathways. We discovered that recurrent gains on chromosome 8q more frequently involve the AGO2 gene than the adjacent MYC locus as the affected minimally amplified genomic region. AGO2 has been understood as a pro-tumorigenic key regulator of microRNA (miR) processing. In primary tumor material and cell line models, AGO2 overrepresentation associated (i) with higher disease burden, (ii) with enhanced in vitro viability and growth of leukemic T-cells, and (iii) with miR-omes and transcriptomes that highlight altered survival signaling, abrogated cell cycle control, and defective DNA damage responses. Moreover, AGO2 elicited immediate, rather than non-RNA mediated, effects in leukemic T-cells. Systems of genetically modulated AGO2 revealed that it enhances TCR signaling, particularly at the level of ZAP70, PLCγ1, and LAT kinase phospho-activation. In global mass-spectrometric analyses, AGO2 interacted with a unique set of partners in a TCR-stimulated context, including the TCR kinases LCK and ZAP70, forming membranous protein complexes. Models of their three-dimensional structure also suggested that AGO2 undergoes post-transcriptional modi-fications by LCK. This novel TCR-associated non-canonical function of AGO2 represents, in addition to TCL1A-mediated TCR signal augmentation, another enhancer mechanism of this important deregulated growth pathway in T-PLL. These findings further emphasize TCR signaling intermediates as candidates for therapeutic targeting.

A new case of trisomy 5 with complex karyotype abnormalities in B-cell prolymphocytic leukemia: a case study

Background

The B-cell prolymphocytic leukemia (B-PLL) diagnosis is challenging due to the superposition with mature B-cell leukemia and/or lymphoma.

Objective

An insight case study of trisomy 5 with complex karyotype abnormalities in B-cell prolymphocytic leukemia.

Subject and methods

A 72-year-old man was referred to the Hematology Department, Qilu Hospital, Shandong University, because of persistent fever (10 days) and lymphocytosis. A detailed diagnostic methods including complete blood count, bone marrow aspiration, flow cytometry, conventional karyotype analysis, fluorescence in situ hybridization (FISH), quantitative real-time polymerase chain reaction (qRT-PCR), next-generation sequencing technology (NGS) used to detect 41 kinds of mutant genes related to hematological malignancies were conducted and reasonable therapeutic regimens including emergent leukapheresis accompanied by basification of urine and hydrotherapy, followed by a regimen of cyclophosphamide and dexamethasone.

Results

Subject white blood cell count was 143.43 × 109/L, and 56% prolymphocytes. He did not show lymphadenopathy but splenomegaly. Immunophenotyping of prolymphocytes was CD5(+low), CD10(−), CD11c(−), CD19(+), CD20(+), cCD22(+), CD23(−), cCD79a(+), CD79b(+), FMC7(±), CD43(−), CD3(−), CD56(−), CD103(−), HLA-DR(+), and Lambda(+). R-banding and FISH revealed that leukemia cells carried extra chromosome 5. Considering the rare occurrence of trisomy 5 found in prolymphocytic leukemia, especially in Asians, with rapid disease progression. We know that median survival of B-PLL is three years after diagnosis, while survival time of this patient was only 1 month.

Conclusion

This study could provide the firsthand materials for precision, medicine and mechanism research in cytogenetics and molecular biology. It inferred that trisomy 5 might be a poor prognosis indicator, providing directions for clinical practice in the foreseeable future.

Advances in Cellular Therapy for T-Cell Prolymphocytic Leukemia

T-cell prolymphocytic leukemia (T-PLL) is a rare, aggressive hematologic malignancy with a poor prognosis. Alemtuzumab (Campath) remains the cornerstone for treatment, with an 80% complete response (CR). Hematopoietic stem cell transplant (HSCT) is considered the standard of care as consolidative therapy in eligible patients. However, allogeneic stem cell transplant is also complicated by increased rates of infections from chemotherapy, acute graft-versus-host disease (GVHD), and chronic GVHD. This review aims to report the available literature on the efficacy and complications of consolidative HSCT. It also discusses the importance of patient selection and pre- and post-transplant complications including atypical infections and GVHD.

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.

Advanced Pathogenetic Concepts in T-Cell Prolymphocytic Leukemia and Their Translational Impact

T-cell prolymphocytic leukemia (T-PLL) is the most common mature T-cell leukemia. It is a typically aggressively growing and chemotherapy-resistant malignancy with a poor prognosis. T-PLL cells resemble activated, post-thymic T-lymphocytes with memory-type effector functions. Constitutive transcriptional activation of genes of the T-cell leukemia 1 (TCL1) family based on genomic inversions/translocations is recognized as a key event in T-PLL's pathogenesis. TCL1's multiple effector pathways include the enhancement of T-cell receptor (TCR) signals. New molecular dependencies around responses to DNA damage, including repair and apoptosis regulation, as well as alterations of cytokine and non-TCR activation signaling were identified as perturbed hallmark pathways within the past years. We currently witness these vulnerabilities to be interrogated in first pre-clinical concepts and initial clinical testing in relapsed/refractory T-PLL patients. We summarize here the current knowledge on the molecular understanding of T-PLL's pathobiology and critically assess the true translational progress around this to help appraisal by caregivers and patients. Overall, the contemporary concepts on T-PLL's pathobiology are condensed in a comprehensive mechanistic disease model and promising interventional strategies derived from it are highlighted.

Recent advances in T-cell lymphoid neoplasms

T Cells comprise many subtypes of specified lymphocytes, and their differentiation and function take place in different tissues. This cellular diversity is also observed in the multiple ways T-cell transformation gives rise to a variety of T-cell neoplasms. This review covers the main types of T-cell malignancies and their specific characteristics, emphasizing recent advances at the cellular and molecular levels as well as differences and commonalities among them.

CCR7 in Blood Cancers - Review of Its Pathophysiological Roles and the Potential as a Therapeutic Target

According to the classical paradigm, CCR7 is a homing chemokine receptor that grants normal lymphocytes access to secondary lymphoid tissues such as lymph nodes or spleen. As such, in most lymphoproliferative disorders, CCR7 expression correlates with nodal or spleen involvement. Nonetheless, recent evidence suggests that CCR7 is more than a facilitator of lymphatic spread of tumor cells. Here, we review published data to catalogue CCR7 expression across blood cancers and appraise which classical and novel roles are attributed to this receptor in the pathogenesis of specific hematologic neoplasms. We outline why novel therapeutic strategies targeting CCR7 might provide clinical benefits to patients with CCR7-positive hematopoietic tumors.

Sustained MRD negative remission in del17p and TP53 mutated B cell prolymphocytic leukemia with ibrutinib and venetoclax

B cell prolymphocytic leukemia is a rare and aggressive disorder often with high risk features including TP53 mutation, deletion 17p and complex karyotype. There is scarcity of data regarding treatment and existing therapies induce short lived remissions. Ibrutinib, a Bruton tyrosine kinase inhibitor, has had success in some patients with high risk features. Venetoclax, a BCL-2 inhibitor, has primarily been used in the relapsed setting. We present a case of B PLL with deletion 17p and mutated TP53 treated with ibrutinib and venetoclax in the frontline setting which resulted in measurable/minimal residual disease negative remission for approximately three years.

B-prolymphocytic leukemia: Is it time to retire this entity?

B-prolymphocytic leukemia (B-PLL) is included as a distinct entity in the current World Health Organization classification of hematolymphoid neoplasms. However, the diagnosis of B-PLL has presented several challenges since its conception, and over the past decades investigations of B-PLL have revealed substantial biologic and molecular heterogeneity. These data have shown that many B-PLL cases present many similarities with other types of small B-cell lymphomas, and that small B-cell lymphomas can undergo prolymphocytoid transformation. As a result, the frequency of B-PLL has markedly decreased, and currently B-PLL is a very rare entity. Most recent studies focused on B-PLL cases have been conducted on limited cohorts, precluding robust conclusions. In this article, we provide a concise historical review of B-PLL and describe the diagnostic and clinical challenges associated with establishing this diagnosis. We also argue that cases currently classified as B-PLL are unlikely to be a unique biologic entity, but rather represent a state of morphologic transformation characterized by many prolymphocytes that is shared by various types of small B-cell lymphoma.

CAR-engineered NK cells; a promising therapeutic option for treatment of hematological malignancies

Adoptive cell therapy has received a great deal of interest in the treatment of advanced cancers that are resistant to traditional therapy. The tremendous success of chimeric antigen receptor (CAR)-engineered T (CAR-T) cells in the treatment of cancer, especially hematological cancers, has exposed CAR's potential. However, the toxicity and significant limitations of CAR-T cell immunotherapy prompted research into other immune cells as potential candidates for CAR engineering. NK cells are a major component of the innate immune system, especially for tumor immunosurveillance. They have a higher propensity for immunotherapy in hematologic malignancies because they can detect and eliminate cancerous cells more effectively. In comparison to CAR-T cells, CAR-NK cells can be prepared from allogeneic donors and are safer with a lower chance of cytokine release syndrome and graft-versus-host disease, as well as being a more efficient antitumor activity with high efficiency for off-the-shelf production. Moreover, CAR-NK cells may be modified to target various antigens while also increasing their expansion and survival in vivo. Extensive preclinical research has shown that NK cells can be effectively engineered to express CARs with substantial cytotoxic activity against both hematological and solid tumors, establishing evidence for potential clinical trials of CAR-NK cells. In this review, we discuss recent advances in CAR-NK cell engineering in a variety of hematological malignancies, as well as the main challenges that influence the outcomes of CAR-NK cell-based tumor immunotherapies.

Development of HDAC Inhibitors Exhibiting Therapeutic Potential in T-Cell Prolymphocytic Leukemia

Epigenetic targeting has emerged as an efficacious therapy for hematological cancers. The rare and incurable T-cell prolymphocytic leukemia (T-PLL) is known for its aggressive clinical course. Current epigenetic agents such as histone deacetylase (HDAC) inhibitors are increasingly used for targeted therapy. Through a structure-activity relationship (SAR) study, we developed an HDAC6 inhibitor KT-531, which exhibited higher potency in T-PLL compared to other hematological cancers. KT-531 displayed strong HDAC6 inhibitory potency and selectivity, on-target biological activity, and a safe therapeutic window in nontransformed cell lines. In primary T-PLL patient cells, where HDAC6 was found to be overexpressed, KT-531 exhibited strong biological responses, and safety in healthy donor samples. Notably, combination studies in T-PLL patient samples demonstrated KT-531 synergizes with approved cancer drugs, bendamustine, idasanutlin, and venetoclax. Our work suggests HDAC inhibition in T-PLL could afford sufficient therapeutic windows to achieve durable remission either as stand-alone or in combination with targeted drugs.

An unusual case of T-cell prolymphocytic leukemia mimicking a cutaneous vasculitis

T-cell prolymphocytic leukemia (T-PLL) is an aggressive post-thymic T-cell malignancy, which accounts for 2% of mature lymphocytic leukemias in adults. Though typically presenting with a brief history of B symptoms, hepatosplenomegaly, and marked lymphocytosis, erythematous or nodular skin rashes involving the trunk or limbs may be seen in 25% to 30% of patients, as well as a purpuric rash in a periorbital distribution. Cutaneous involvement typically presents in the context of patients with an established history of T-PLL, but it can less frequently present as an initial symptom heralding the diagnosis. An unusual case of T-PLL is described, presenting initially as palmoplantar ulcerated nodules with an initial biopsy suggestive of perniosis, followed by rapid progression of dark violaceous and bright red papules throughout the body after initiation of Obinutuzumab. The diagnosis of T-PLL was subsequently fully supported by the clinical, laboratory, cytologic, and immunophenotypic findings. This case highlights the importance of a multidisciplinary team approach to address such rare and atypical presentations.

Shikonin Derivatives from Onsoma visianii Decrease Expression of Phosphorylated STAT3 in Leukemia Cells and Exert Antitumor Activity

Antitumor effects of shikonins on chronic lymphocytic leukemia (CLL) and B-cell prolymphocytic leukemia (B-PLL) are mostly unexplored. The antitumor activity of shikonins, isolated from Onosma visianii Clem (Boraginaceae), in BCL1, mouse CLL cells and JVM-13, human B-PLL cells was explored in this study. The cytotoxicity of shikonin derivatives was measured by an MTT test. Cell death, proliferation, cell cycle, and expression of molecules that control these processes were analyzed by flow cytometry. Expression of STAT3-regulated genes was analyzed by real-time q-RT-PCR (Quantitative Real-Time Polymerase Chain Reaction). The antitumor effects of shikonin derivatives in vivo were analyzed, using flow cytometry, by detection of leukemia cells in the peripheral blood and spleens of mice intravenously injected with BCL1 cells. The two most potent derivatives, isobutyrylshikonin (IBS) and α-methylbutyrylshikonin (MBS), induced cell cycle disturbances and apoptosis, inhibited proliferation, and decreased expression of phospho-STAT3 and downstream-regulated molecules in BCL1 and JVM-13 cells. IBS and MBS decreased the percentage of leukemia cells in vivo. The link between the decrease in phosphorylated STAT3 by MBS and IBS and BCL1 cell death was confirmed by detection of enhanced cell death after addition of AG490, an inhibitor of Jak2 kinase. It seems that IBS and MBS, by decreasing STAT3 phosphorylation, trigger apoptosis, inhibit cell proliferation, and attenuate leukemia cell stemness.

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.

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.

De novo chronic lymphocytic leukemia/prolymphocytic leukemia or B-cell prolymphocytic leukemia? The importance of integrating clinico-morphological and immunophenotypic findings in distinguishing chronic lymphoproliferative diseases with circulating phase

B-cell prolymphocytic leukemia (B-PLL) is an extremely rare disease, accounting for approximately 1% of the lymphocytic leukemias. B-PLL generally occurs in older people. It is characterized by the presence of more than 55% prolymphocytes in the peripheral blood (PB), no or minimal lymphadenopathy, massive splenomegaly, and very high white blood cell counts. The prognosis of B-PLL patients is generally poor, with a median survival of 3 years, although a subset of patients may show a prolonged survival. Herein, we report a case of a 70-year-old male with weakness, generalized lymphadenopathy, and moderate splenomegaly at the initial presentation. Hematologic examination revealed lymphocytic leukocytosis, favoring a chronic lymphoproliferative disorder (CLPD). The key to decoding the precise CLPD was a combination of the clinical profile, morphologic findings on the peripheral blood and the bone marrow, immunophenotypic analysis, and cytogenetic study. The best diagnosis proffered was a de novo chronic lymphocytic leukemia/prolymphocytic leukemia. There was no prior history of lymphoproliferative disorder or lymphocytic leukocytosis. Discriminating this entity from other lymphoproliferative disorders is crucial as the treatment and prognosis are varied compared to the other lymphoproliferative disorders. The diagnostic conundrum encountered and the incredible utility of ancillary studies in such a scenario are highlighted in this study.

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.

Impact of Genetics on Mature Lymphoid Leukemias and Lymphomas

Recurrent genetic aberrations have long been recognized in mature lymphoid leukemias and lymphomas. As conventional karyotypic and molecular cloning techniques evolved in the 1970s and 1980s, multiple cytogenetic aberrations were identified in lymphomas, often balanced translocations that juxtaposed oncogenes to the immunoglobulin (IG) or T-cell receptor (TR) loci, leading to dysregulation. However, genetic characterization and classification of lymphoma by conventional cytogenetic methods is limited by the infrequent occurrence of recurrent karyotypic abnormalities in many lymphoma subtypes and by the frequent difficulty in growing clinical lymphoma specimens in culture to obtain informative karyotypes. As higher-resolution genomic techniques developed, such as array comparative genomic hybridization and fluorescence in situ hybridization, many recurrent copy number changes were identified in lymphomas, and copy number assessment of interphase cells became part of routine clinical practice for a subset of diseases. Platforms to globally examine mRNA expression led to major insights into the biology of several lymphomas, although these techniques have not gained widespread application in routine clinical settings. With the advent of next-generation sequencing (NGS) techniques in the early 2000s, numerous insights into the genetic landscape of lymphomas were obtained. In contrast to the myeloid malignancies, most common lymphomas exhibit an at least somewhat mutationally complex genome, with few single driver mutations in the majority of patients. However, many recurrently mutated pathways have been identified across lymphoma subtypes, informing targeted therapeutic approaches that are beginning to make meaningful changes in the treatment of lymphoma. In addition to the ability to identify possible therapeutic targets, NGS techniques are highly amenable to the tracking of residual lymphoma following therapy, because of the presence of unique genetic "fingerprints" in lymphoma cells due to V(D)-J recombination at the antigen receptor loci. This review will provide an overview of the impact of novel genetic technologies on lymphoma classification, biology, and therapy.

CCR7 as a novel therapeutic target in t-cell PROLYMPHOCYTIC leukemia

T-cell prolymphocytic leukemia (T-PLL) is a poor prognostic disease with very limited options of efficient therapies. Most patients are refractory to chemotherapies and despite high response rates after alemtuzumab, virtually all patients relapse. Therefore, there is an unmet medical need for novel therapies in T-PLL. As the chemokine receptor CCR7 is a molecule expressed in a wide range of malignancies and relevant in many tumor processes, the present study addressed the biologic role of this receptor in T-PLL. Furthermore, we elucidated the mechanisms of action mediated by an anti-CCR7 monoclonal antibody (mAb) and evaluated whether its anti-tumor activity would warrant development towards clinical applications in T-PLL. Our results demonstrate that CCR7 is a prognostic biomarker for overall survival in T-PLL patients and a functional receptor involved in the migration, invasion, and survival of leukemic cells. Targeting CCR7 with a mAb inhibited ligand-mediated signaling pathways and induced tumor cell killing in primary samples. In addition, directing antibodies against CCR7 was highly effective in T-cell leukemia xenograft models. Together, these findings make CCR7 an attractive molecule for novel mAb-based therapeutic applications in T-PLL, a disease where recent drug screen efforts and studies addressing new compounds have focused on chemotherapy or small molecules.

Biomarker-driven management strategies for peripheral T cell lymphoma

Peripheral T cell lymphomas are heterogeneous diseases which remain treatment challenges. Recent advances in molecular and genomic profiling have provided unprecedented insight into disease pathogenesis driven by distinct cells of origins and molecular pathways. The discovery and clinical application of molecular biomarkers in PTCL subtypes has the potential to transform personalized care for patients with PTCL in diagnosis, prognosis, and therapy. Targeting CD30+ PTCL with the antibody-drug conjugate brentuximab vedotin in the relapsed setting and in combination with chemotherapy in the frontline setting has improved patient survivals. Epigenetic modifying agents, including HDAC inhibitors and hypomethylating agents, have demonstrated broad clinical efficacy and durability and are in clinical development for combination strategies for both relapsed and frontline settings. Wide-ranging novel agents targeting critical intracellular pathways and tumor microenvironment are in active exploration to define clinical activities. This review summarizes PTCL-specific biomarkers which are increasingly incorporated in clinical practice to guide precision diagnosis and personalized treatment.

A Rare Association: Autoimmune Hemolytic Anemia With Indolent T-Cell Prolymphocytic Leukemia

The association of warm autoimmune hemolytic anemia (wAIHA) with various lymphoproliferative disorders is well reported in the literature. But the association of wAIHA with T-cell prolymphocytic leukemia (T-PLL), a very rare lymphoproliferative disorder, has never been reported. A 71-year-old man was in his usual state of health until three years ago when he developed intermittent bouts of worsening anemia associated with mild peripheral blood lymphocytosis. He was diagnosed with wAIHA and steroid therapy was initiated, resulting in an improvement in the hemoglobin level of the patient. His lymphocyte count remained persistently elevated but he did not develop any malignancy-related signs or symptoms. A diagnosis of ‘indolent’ T-cell prolymphocytic leukemia (small cell variant) was made by combining distinctive clinical, morphologic, immunophenotypic, and cytogenetic analysis. His wAIHA went into complete remission and steroid therapy was successfully tapered off. He has not required any treatment for his T-PLL during the last two years' follow-up.

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.

Effective upfront treatment with low-dose ibrutinib for a patient with B cell prolymphocytic leukemia

B cell prolymphocytic leukemia (B-PLL) is a rare and aggressive disease that is associated with poor survival. Although initially asymptomatic patients do not require therapy, most patients will progress and inevitably require treatment. More than 50% of patients with B-PLL carry abnormalities in the TP53 tumor suppressor gene and/or complex karyotype and show resistance to conventional chemotherapy. The efficacy of ibrutinib, a B cell receptor inhibitor, for B-PLL with the TP53 abnormality as second-line therapy was recently demonstrated. We herein report that low-dose ibrutinib as upfront therapy induced a complete response in a B-PLL patient with the TP53 abnormality, whose condition has since remained stable with no recurrence for 12 months. Effective treatments for B-PLL are lacking and given its rarity, prospective comparative therapies are not yet available. This case suggests that upfront therapy with ibrutinib improves the outcome of B-PLL.

What is new in mature T-cell leukemias?

Mature T-cell and NK-cell leukemias represent a clinically heterogeneous group of diseases, ranging from indolent expansions of large granular lymphocytes, to aggressive diseases that are associated with a fulminant clinical course. Recent advances in genomic methodologies have massively increased the understanding of the pathogenesis of this group of diseases. While the entities are genetically heterogeneous, JAK-STAT pathway activation appears to be important across these disorders. The identification of constitutively activated pathways and the emergence of novel targeted pharmaceutical agents raise the expectation that more effective therapies will be identified for these disorders in the coming years.

JAK/STAT-Activating Genomic Alterations Are a Hallmark of T-PLL

T-cell prolymphocytic leukemia (T-PLL) is a rare and poor-prognostic mature T-cell leukemia. Recent studies detected genomic aberrations affecting JAK and STAT genes in T-PLL. Due to the limited number of primary patient samples available, genomic analyses of the JAK/STAT pathway have been performed in rather small cohorts. Therefore, we conducted—via a primary-data based pipeline—a meta-analysis that re-evaluated the genomic landscape of T-PLL. It included all available data sets with sequence information on JAK or STAT gene loci in 275 T-PLL. We eliminated overlapping cases and determined a cumulative rate of 62.1% of cases with mutated JAK or STAT genes. Most frequently, JAK1 (6.3%), JAK3 (36.4%), and STAT5B (18.8%) carried somatic single-nucleotide variants (SNVs), with missense mutations in the SH2 or pseudokinase domains as most prevalent. Importantly, these lesions were predominantly subclonal. We did not detect any strong association between mutations of a JAK or STAT gene with clinical characteristics. Irrespective of the presence of gain-of-function (GOF) SNVs, basal phosphorylation of STAT5B was elevated in all analyzed T-PLL. Fittingly, a significant proportion of genes encoding for potential negative regulators of STAT5B showed genomic losses (in 71.4% of T-PLL in total, in 68.4% of T-PLL without any JAK or STAT mutations). They included DUSP4, CD45, TCPTP, SHP1, SOCS1, SOCS3, and HDAC9. Overall, considering such losses of negative regulators and the GOF mutations in JAK and STAT genes, a total of 89.8% of T-PLL revealed a genomic aberration potentially explaining enhanced STAT5B activity. In essence, we present a comprehensive meta-analysis on the highly prevalent genomic lesions that affect genes encoding JAK/STAT signaling components. This provides an overview of possible modes of activation of this pathway in a large cohort of T-PLL. In light of new advances in JAK/STAT inhibitor development, we also outline translational contexts for harnessing active JAK/STAT signaling, which has emerged as a ‘secondary’ hallmark of T-PLL.

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.

CAR-NK cell therapeutics for hematologic malignancies: hope is on the horizon

Chimeric antigen receptor (CAR)-T-cell therapy has achieved significant success in the treatment of hematologic malignancies. However, treatment-related toxicity and side effects remain the major drawbacks. As an important effector cell in innate immunity, natural killer (NK) cells exert strong antitumor functions and have better application prospects in the immunotherapy of hematologic malignancies. Compared with T cells, NK cells exhibit several advantages such as MHC-independent recognition. CAR-modified NK (CAR-NK) cells may exhibit a better ability of killing tumor cells. Herein, we review mainly preclinical data related to the development of CAR-NK cells in treating blood cancers.

B-cell Prolymphocytic Leukemia: Case Report and Challenges on a Diagnostic and Therapeutic Forefront

B-cell prolymphocytic leukemia (B-PLL) is a rare malignancy of mature B-cells with characteristic morphologic, immunophenotypic, cytogenetic, and molecular features characterized by late onset (median age 69 years), an aggressive clinical course, refractoriness to chemotherapy, and median survival of around three years. Treatment is influenced by the presence or absence of specific high-risk genetic mutations like 17P/TP53 deletion, the presence of which translates into poor prognosis. Patients without 17P deletion, who are <70 years, without significant co-morbidities, are initially treated with a combination chemotherapy regimen used for chronic lymphocytic leukemia (CLL) such as fludarabine, cyclophosphamide, and rituximab. On the other hand, patients with a 17P deletion, age >70 years, with multiple co-morbidities, receive ibrutinib or alemtuzumab as the initial therapy. Relapsed or refractory cases are managed with BCL-2 signaling inhibitors like venetoclax. We discuss the case of an 84-year-old male with B-PLL (positive TP53 mutation), resistant to ibrutinib therapy, with extremely high white blood cell (WBC) counts, thus creating a dilemma regarding the best treatment in the second-line setting.

Sensitizing the interdisciplinary team to desensitizations: An alemtuzumab case report

INTRODUCTION

We describe a case of alemtuzumab (Campath®) hypersensitivity requiring desensitization within the medical intensive care unit (MICU) in a patient with T-cell prolymphocytic leukemia.

CASE REPORT

We adopted a desensitization protocol from Gutierrez-Fernandez et al., which included three aliquots (0.15 mg intravenously (IV), 1.5 mg IV, and 28.5 mg IV) given approximately 1 h apart on day 1 followed by a full 30 mg dose IV on day 3. Unlike prior attempts to administer alemtuzumab to this patient, she tolerated the medication well and did not require any rescue medications.

MANAGEMENT AND OUTCOME

Successful plan development required a significant amount of strategic communication between hematology/oncology and MICU-related physicians, pharmacists, and nurses to ensure a safe and effective desensitization. The first step of planning required creation of a desensitization order set with directions for medication preparation and administration, premedications, and available medications in the event of an adverse reaction or anaphylaxis. Anaphylactoid-related medications were prepared at bedside and ready for administration prior to beginning the desensitization. Alemtuzumab was compounded in a chemotherapy-certified hood and verified by at least two chemotherapy-certified pharmacists. Foreword planning was also necessary to ensure multiple people were available or present at bedside for the desensitization, including a chemotherapy-certified nurse, a second chemotherapy-certified nurse for verification, a critical care-certified pharmacist, a pulmonary/critical care attending physician, and hematology attending physician.

DISCUSSION

This case exemplifies the importance of clear and coordinated communication between different healthcare fields to safely and effectively complete extensive protocols such as desensitization strategies.

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.