T-cell large granular lymphocyte leukemia

A modern view of LGL leukemia

ABSTRACT

Large granular lymphocytic leukemia (LGLL) is a rare lymphoproliferative chronic disorder characterized by expansion of either T or natural killer (NK) cytotoxic cells. In contrast to Epstein-Barr virus-induced aggressive NK-LGLL, chronic T-LGLL and NK-LGLL are indolent diseases affecting older patients with a median age of 66.5 years. LGLL is frequently associated with autoimmune disorders, most frequently rheumatoid arthritis. An auto-/alloantigen is tentatively implicated in disease initiation. Large granular lymphocyte expansion is then triggered by proinflammatory cytokines such as interleukin-15, macrophage inflammatory protein 1 (MIP-1), and RANTES (regulated upon activation, normal T cell expressed, and secreted). This proinflammatory environment contributes to deregulation of proliferative and apoptotic pathways. After the initial description of the JAK-STAT pathway signaling activation in the majority of patients, recurrent STAT3 gain-of-function mutations have been reported. The JAK-STAT pathway plays a key role in LGL pathogenesis by promoting survival, proliferation, and cytotoxicity. Several recent advances have been made toward understanding the molecular landscapes of T- and NK-LGLL, identifying multiple recurrent mutations affecting the epigenome, such as TET2 or KMT2D, and cross talk with the immune microenvironment, such as CCL22. Despite an indolent course, published series suggest that the majority of patients eventually need treatment. However, it is noteworthy that many patients may have a long-term observation period without ever requiring therapy. Treatments rely upon immunosuppressive drugs, namely cyclophosphamide, methotrexate, and cyclosporine. Recent advances have led to the development of targeted approaches, including JAK-STAT inhibitors, cytokine targeting, and hypomethylating agents, opening new developments in a still-incurable disease.

Efficacy of ruxolitinib in the treatment of relapsed/refractory large granular lymphocytic leukaemia

Large granular lymphocytic (LGL) leukaemia is a rare chronic lymphoproliferative disorder characterized by an expansion of cytotoxic T or NK cells. Despite a usually indolent evolution, most patients will require a treatment over the course of the disease because of cytopenia or symptomatic associated autoimmune disorders. First-line treatment is based on immunosuppressive agents, namely cyclophosphamide, methotrexate and ciclosporin. However, relapses are frequent, and there is no consensus on the management of relapsed/refractory patients. The implication of the JAK/STAT pathway in the pathogenesis of this disease has prompted our group to propose treatment with ruxolitinib. A series of 21 patients who received this regimen is reported here. Ten patients (47.6%) were refractory to the three main immunosuppressive drugs at the time of ruxolitinib initiation. Ruxolitinib yielded an overall response rate of 86% (n = 18/21), including 3 complete responses and 15 partial responses. With a median follow-up of 9 months, the median response duration was 4 months. One-year event-free survival and 1-year overall survival were 57% and 83% respectively. Mild side effects were observed. Biological parameters, notably neutropenia and anaemia, improved significantly, and complete molecular responses were evidenced. This study supports ruxolitinib as a valid option for the treatment of relapsed/refractory LGL leukaemia.

T-cell Large Granular Lymphocytic Leukemia with a STAT3 mutation successfully treated with Cord Blood Transplantation

A 64-year-old woman presented with agranulocytosis, anemia, and bacteremia, leading to a diagnosis of T-cell large granular lymphocytic leukemia (T-LGLL). A molecular analysis identified a signal transducer and activator of transcription 3 (STAT3) Y640F variant. Initial treatment with cyclophosphamide and prednisolone did not improve her condition, but serious infections were observed. The patient underwent cord blood transplantation (CBT) after preconditioning with fludarabine, busulfan, and total body irradiation, yielding a STAT3 Y640F variant disappearance, based on allele-specific quantitative polymerase chain reaction (AS-qPCR). In this case, CBT is a promising refractory T-LGLL treatment option, and the STAT3 Y640F variant AS-qPCR is a T-LGLL activity marker.

T-cell large granular lymphocytic leukemia with a STAT3 mutation successfully treated with cord blood transplantation

A 64-year-old woman presented with agranulocytosis, anemia, and bacteremia, leading to a diagnosis of T-cell large granular lymphocytic leukemia (T-LGLL). A molecular analysis identified a signal transducer and activator of transcription 3 (STAT3) Y640F variant. Initial treatment with cyclophosphamide and prednisolone did not improve her condition, but serious infections were observed. The patient underwent cord blood transplantation (CBT) after preconditioning with fludarabine, busulfan, and total body irradiation, yielding a STAT3 Y640F variant disappearance, based on allele-specific quantitative polymerase chain reaction (AS-qPCR). In this case, CBT is a promising refractory T-LGLL treatment option, and the STAT3 Y640F variant AS-qPCR is a T-LGLL activity marker.

Clinical characteristics and treatment outcomes of Asian patients with T-cell large granular lymphocytic Leukemia: a single-center analysis of 67 cases

Large granular lymphocytic (LGL) leukemia is a clonal lymphoproliferative disorder of LGLs derived from cytotoxic T lymphocytes or natural killer cells. However, the clinical features and treatment responses are still not fully understood because of the rarity of the disease. To describe and assess a cohort of patients with T-cell large granular lymphocytic leukemia (T-LGLL). Single-center, retrospective, observational study. We retrospectively collected the clinical data of patients diagnosed with T-LGLL at Seoul National University Hospital since 2006. We included 67 patients in this study. The median age at diagnosis was 60 years. Additionally, 37 patients (55%) were symptomatic, and 25 (37%) had splenomegaly; 54 patients (81%) required treatment. Cyclophosphamide (n = 35), methotrexate (n = 25), and cyclosporin A (n = 19) were used most frequently for treatment, and their overall response rates were similar: cyclophosphamide (77%), methotrexate (64%), and cyclosporin A (63%). Splenomegaly was associated with an increased response rate to first-line therapy and a decreased complete response rate. Thrombocytopenia was associated with decreased response rates to cyclophosphamide, methotrexate, cyclosporin A, and steroids. In contrast, a high LGL number (> 2000/µL) in the peripheral blood smear was associated with increased response rates to cyclophosphamide, methotrexate, cyclosporin A, and steroids. This study describes the clinical features and treatment outcomes of patients with T-LGLL, providing valuable information for clinical decision-making regarding T-LGLL treatment.

Large Granular Lymphocytic Leukemia: Clinical Features, Molecular Pathogenesis, Diagnosis and Treatment

Large granular lymphocytic (LGL) leukemia is a lymphoproliferative disorder characterized by persistent clonal expansion of mature T- or natural killer cells in the blood via chronic antigenic stimulation. LGL leukemia is associated with specific immunophenotypic and molecular features, particularly STAT3 and STAT5 mutations and activation of the JAK-STAT3, Fas/Fas-L and NF-κB signaling pathways. Disease-related deaths are mainly due to recurrent infections linked to severe neutropenia. The current treatment is based on immunosuppressive therapies, which frequently produce unsatisfactory long-term responses, and for this reason, personalized approaches and targeted therapies are needed. Here, we discuss molecular pathogenesis, clinical presentation, associated autoimmune disorders, and the available treatment options, including emerging therapies.

The complex relationship between large granular lymphocyte leukemia and rheumatic disease

INTRODUCTION

Large granular lymphocytic (LGL) leukemia is a rare lymphoproliferative disorder characterized by an expansion of clonal T or NK lymphocytes. Neutropenia-related infections represent the main clinical manifestation. Even if the disease follows an indolent course, most patients will ultimately need treatment in their lifetime. Interestingly, LGL leukemia is characterized by a high frequency of autoimmune disorders with rheumatoid arthritis being the most frequent.

AREAS COVERED

This review covers the pathophysiology, clinic-biological features and the advances made in the treatment of LGL leukemia. A special focus will be made on the similarities in the pathophysiology of LGL leukemia and the frequently associated rheumatic disorders.

EXPERT OPINION

Recent advances in the phenotypic and molecular characterization of LGL clones have uncovered the key role of JAK-STAT signaling in the pathophysiology linking leukemic cells expansion and autoimmunity. The description of the molecular landscape of T- and NK-LGL leukemia and the improved understanding of the associated rheumatic disorders open the way to the development of new targeted therapies effective on both conditions.

Not all LGL leukemias are created equal

Large Granular Lymphocyte (LGL) Leukemia is a rare, heterogeneous even more that once thought, chronic lymphoproliferative disorder characterized by the clonal expansion of T- or NK-LGLs that requires appropriate immunophenotypic and molecular characterization. As in many other hematological conditions, genomic features are taking research efforts one step further and are also becoming instrumental in refining discrete subsets of LGL disorders. In particular, STAT3 and STAT5B mutations may be harbored in leukemic cells and their presence has been linked to diagnosis of LGL disorders. On clinical grounds, a correlation has been established in CD8+ T-LGLL patients between STAT3 mutations and clinical features, in particular neutropenia that favors the onset of severe infections. Revisiting biological aspects, clinical features as well as current and predictable emerging treatments of these disorders, we will herein discuss why appropriate dissection of different disease variants is needed to better manage patients with LGL disorders.

Large Granular Lymphocytic Leukemia: Current State of Diagnosis, Pathogenesis and Treatment

PURPOSE OF REVIEW

This manuscript aims at updating the knowledge on the clinico-biological characteristics, pathogenesis, and the diagnostic challenges of T-LGLL and CLPD-NK disorders and reviews the advances in the management and treatment of these patients.

RECENT FINDINGS

It has been shown that clonal large granular lymphocyte (LGL) expansions arise from chronic antigenic stimulation, leading to resistance to apoptosis. All the above findings have facilitated the diagnosis of LGLL and provided insights in the pathogenesis of the disease. At present, there is no standard first-line therapy for the disease. Immunosuppressive agents are the treatment routinely used in clinical practice. However, these agents have a limited capacity to eradicate the LGL clone and induce long-lasting remission. Advances in the knowledge of pathogenesis have made it possible to explore new therapeutic targets with promising results. Since LGLL is a rare disease, international efforts are needed to carry on prospective clinical trials with new potentially active drugs that could include a large number of patients.

Large granular lymphocytic leukemia - A retrospective study of 319 cases

Large granular lymphocytic leukemia (LGLL) is a rare hematological malignancy that arises from cytotoxic T lymphocytes (T-LGLL) in 85% of cases and natural killer (NK) cells in the rest. A significant knowledge gap exists regarding the pathogenesis, treatment choices, and prognostic factors of LGLL. We report a cohort of 319 consecutive LGLL patients who presented to our cancer center between 2001 and 2020. A total of 295 patients with T-LGLL and 24 with chronic NK-cell lymphoproliferative disorder (CLPD-NK) were identified. The median age was 65 years (range, 17-90 years). Eighty-three patients (26.0%) had autoimmune diseases. A total of 119 patients (37.3%) had coexisting malignancies, 66 (20.7%) had solid tumors, and 59 (18.5%) had hematological malignancies. Most coexisting malignancies were diagnosed before the diagnosis of LGLL. Treatment was needed for 57% of patients. Methotrexate (MTX), cyclophosphamide (Cy), and cyclosporine A (CSA) were most used and had similar response rates between 61.5%-74.4%. Cy produced more complete responses (32.3%) compared to MTX and CSA (15.7% and 23.1%, respectively). Thrombocytopenia, splenomegaly, and female gender (after controlling for autoimmune diseases) were associated with decreased response rates to MTX, CSA, or Cy. Autoimmune diseases were associated with increased response rates. Thrombocytopenia was an independent risk factor for worse survival.

Clinical outcomes in T-cell large granular lymphocytic leukaemia: prognostic factors and treatment response

T-cell large granular lymphocytic leukaemia (T-LGLL) is an incurable leukaemia characterised by clonal proliferation of abnormal cytotoxic T cells that can result in severe neutropenia, transfusion-dependent anaemia and pancytopenia requiring treatment. The most commonly used agents, methotrexate (MTX), cyclophosphamide (Cy) and cyclosporine primarily produce partial remissions (PRs), with few complete responses (CRs). We evaluated the clinical course and treatment response of 60 consecutive patients with T-LGLL to evaluate clinical outcomes and future potential treatment directions. Impaired overall survival was noted among male patients, patients with elevated lactate dehydrogenase, and those without rheumatoid arthritis. Cy was the most efficacious second-line agent, with a 70% overall response rate (ORR; three CR, four PR). All patients who failed frontline MTX responded to second-line Cy. In the relapsed or Cy-refractory setting, alemtuzumab (n = 4) and pentostatin (n = 3) had an ORR of 50% and 66%, respectively, while duvelisib induced a long-term response in one patient. In this large, retrospective analysis, our results suggest Cy is a highly effective therapy for second-line treatment in T-LGLL and should be considered a strong candidate for up-front therapy in select high-risk patients. Prospective studies evaluating pentostatin, alemtuzumab and novel agents, such as duvelisib, are needed for patients with relapsed/refractory T-LGLL.

Belinostat in Relapsed/Refractory T-Cell Large Granular Lymphocyte Leukemia

T-cell large granular lymphocyte (LGL) leukemia is a rare indolent neoplasm primarily treated with immunosuppression. Few therapies and no consensus exist for the optimal treatment of T-cell LGL leukemia refractory to immunosuppressive therapy. Here, we report a case of relapsed/refractory T-cell LGL treated with belinostat. A 57-year-old male presented with lymphocytosis and anemia and was found to have T-cell LGL, requiring frequent packed red blood cell transfusions. He was initially treated with methotrexate with no response after 7 months. He was then switched to cyclosporine and cyclophosphamide and experienced transfusion independence for 42 months before disease relapse. He was then started on belinostat with noted subsequent transfusion independence for greater than 15 months to date and decreased disease involvement on bone marrow biopsy. To our knowledge, this is the first reported case of belinostat use in relapsed/refractory T-cell LGL leukemia which resulted in a durable clinical and biologic response.

Latest Advances in the Diagnosis and Treatment of Large Granular Lymphocytic Leukemia

Large granular lymphocyte (LGL) leukemia has been recognized in the World Health Organization classifications among mature T cell and natural killer cell neoplasms and is divided into three categories. Chronic T cell leukemia and natural killer cell lymphocytosis can be considered as a similar spectrum of an indolent disease characterized by cytopenias and autoimmune conditions. The last category, aggressive natural killer cell LGL leukemia is very rare, related to Epstein-Barr virus, and seen mainly in young Asian people. Clonal LGL expansion arises from chronic antigenic stimulation sustained by interleukin-15 and platelet-derived growth factor cytokine signal. Those leukemic cells are resistant to apoptosis, mainly because of constitutive activation of survival pathways including Jak/Stat, MapK, Pi3k-Akt, RasRaf-1, MEK1/ERK, sphingolipid, and NFκB. Stat3 constitutive activation is the hallmark of this lymphoproliferative disorder. Socs3 is downregulated, but no mutation could be found to explain this status. However, several somatic mutations, including Stat3, Stat5b, and tumor necrosis factor alpha-induced protein 3, have been demonstrated recently in LGL leukemia; they are identified in half of patients and cannot explain by themselves LGL leukemogenesis. Recurrent infections as a result of chronic neutropenia, anemia, and autoimmune disorders are the main complications related to LGL leukemia. Despite an indolent presentation, 10% of patients die, mainly because of infectious complications. Current treatments are based on immunosuppressive therapies. A better mechanistic understanding of LGL leukemia will allow future consideration of a personalized therapeutic approach perhaps based on Jak/Stat inhibitors, which may offer better results than current immunosuppressive therapy.

Large granular lymphocytosis after transplantation

Post-transplant lymphoproliferative disorders (PTLD) represent a heterogeneous group of diseases that occur following transplantation. Large granular lymphocytic (LGL) lymphocytosis is one type of PTLD, ranging from reactive polyclonal self-limited expansion to oligo/monoclonal lymphocytosis or even to overt leukaemia. LGL lymphocytosis in transplant recipients may present as a relatively indolent version of the condition and may be more common than reported, but its natural history and clinical course have not been well described, and the lack of a reliable classification system has limited studies on this disease. Patients with unexplained cytopenias, autoimmune manifestations, or unexpected remissions may be mislabelled. The purpose of this review was to evaluate the clinical features, immunophenotypes, etiopathogenesis, diagnosis, outcomes and treatment of post-transplantation LGL lymphocytosis. In conclusion, LGL lymphocytosis is a frequent occurrence after transplantation that correlates with certain procedural variables and post-transplant events. LGL lymphocytosis should be considered in patients with unexplained lymphocytosis or when pancytopenia develops after transplantation. The diagnosis of LGL lymphocytosis requires a demonstration of monoclonality, but clonality does not indicate malignancy. Additional studies are necessary to further delineate the potential effects of large granular lymphocytes in the long-term prognosis of post-transplant patients.

Clinical features and treatment outcomes in large granular lymphocytic leukemia (LGLL)

Large granular lymphocytic leukemia (LGLL) represents a clonal/oligoclonal lymphoproliferation of cytotoxic T and natural killer cells often associated with STAT3 mutations. When symptomatic, due to mostly anemia and neutropenia, therapy choices are often empirically-based, because only few clinical trials and systematic studies have been performed. Incorporating new molecular and flow cytometry parameters, we identified 204 patients fulfilling uniform criteria for LGLL diagnoses and analyzed clinical course with median follow-up of 36 months, including responses to treatments. While selection of initial treatment was dictated by clinical features, the initial responses, as well as overall responses to methotrexate (MTX), cyclosporine (CsA), and cyclophosphamide (CTX), were similar at 40-50% across drugs. Sequential use of these drugs resulted in responses in most cases: only 10-20% required salvage therapies such as ATG, Campath, tofacitinib, splenectomy or abatacept. MTX yielded the most durable responses. STAT3-mutated patients required therapy more frequently and had better overall survival.

LGL leukemia: from pathogenesis to treatment

Large granular lymphocyte (LGL) leukemia has been recognized by the World Health Organization classifications amongst mature T-cell and natural killer (NK) cell neoplasms. There are 3 categories: chronic T-cell leukemia and NK-cell lymphocytosis, which are similarly indolent diseases characterized by cytopenias and autoimmune conditions as opposed to aggressive NK-cell LGL leukemia. Clonal LGL expansion arise from chronic antigenic stimulation, which promotes dysregulation of apoptosis, mainly due to constitutive activation of survival pathways including Jak/Stat, MapK, phosphatidylinositol 3-kinase-Akt, Ras-Raf-1, MEK1/extracellular signal-regulated kinase, sphingolipid, and nuclear factor-κB. Socs3 downregulation may also contribute to Stat3 activation. Interleukin 15 plays a key role in activation of leukemic LGL. Several somatic mutations including Stat3, Stat5b, and tumor necrosis factor alpha-induced protein 3 have been demonstrated recently in LGL leukemia. Because these mutations are present in less than half of the patients, they cannot completely explain LGL leukemogenesis. A better mechanistic understanding of leukemic LGL survival will allow future consideration of a more targeted therapeutic approach than the current practice of immunosuppressive therapy.

Clinical Features, Pathogenesis, and Treatment of Large Granular Lymphocyte Leukemias

Large granular lymphocytes (LGLs) are large lymphocytes with azurophilic granules in their cytoplasm. LGLs are either natural killer (NK) cells or T lymphocytes. Expansions of the LGLs in the peripheral blood are seen in various conditions, including three clonal disorders: T-cell LGL (T-LGL) leukemia, chronic lymphoproliferative disorders of NK cells (CLPD-NK), and aggressive NK-cell leukemia (ANKL). However, the monoclonal and polyclonal expansion of LGLs has been associated with many other conditions. The present article describes these LGL disorders, with special emphasis on the clinical features, pathogenesis, and treatments of the three above-mentioned clonal disorders.

Alemtuzumab in T-cell large granular lymphocytic leukaemia: interim results from a single-arm, open-label, phase 2 study

Background

T-cell large granular lymphocytic leukemia (T-LGL) is a lymphoproliferative disease presenting with immune-mediated cytopenias and characterized by clonal expansion of cytotoxic CD3⁺CD8⁺ lymphocytes. Methotrexate, cyclosporine, or cyclophosphamide improve cytopenias in 50% of patients as first therapy, but the activity of an anti-CD52 monoclonal antibody, alemtuzumab, is not defined in T-LGL.

Methods

Twenty-five consecutive subjects with T-LGL were enrolled from October 2006 to March 2015 at the National Institutes of Health (www.clinicaltrials.gov-NCT00345345). Alemtuzumab was administered at 10 mg/day intravenously for 10 days. The primary endpoint was haematologic response at 3 months. Analysis was intention to treat. Here we report the protocol specified interim benchmark of a phase II clinical trial using alemtuzumab in T-LGL.

Findings

In this heterogeneous, previously treated cohort, 14/25 (56%; 95% CI, 37–73%) subjects had a haematological response at 3 months. In T-LGL cases not associated with myelodysplasia or marrow transplantation, the response rate was 14/19 (74%; 95% CI, 51–86%). First dose infusion reactions were common which improved with symptomatic therapy. EBV and CMV reactivations were common and subclinical. In only 2 patients pre-emptive anti-CMV therapy was instituted. There were no cases of EBV or CMV disease. Alemtuzumab induced sustained reduction of absolute clonal population of T-cytotoxic lymphocytes, as identified by TCRBV-receptor phenotype, but the abnormal clone serendipitously persisted in responders. STAT3 mutations in the SH2 domain, identified in ten subjects, did not correlate with response. When compared with healthy volunteers, T-LGL subjects showed a distinct plasma cytokine and JAK-STAT signature prior to treatment, but neither correlated to response.

Interpretation

This is the largest and only prospective cohort of T-LGL subjects treated with alemtuzumab yet reported. The high activity with a single course of a lymphocytotoxic agent in a mainly relapsed and refractory suggests that haematologic response outcomes can be accomplished without the need for continued use of oral immunosuppression.

Funding

This research was supported by the Intramural Research Program of the NIH, National Heart, Lung, and Blood Institute.

Treating rare lymphoproliferative malignancies: a focus on indolent large granular lymphocytic leukemia

SUMMARY 

Large granular lymphocyte leukemia is a heterogeneous group of lymphoproliferative disorders that arises from mature T cells or NK cells. These disorders are relatively uncommon and usually present with cytopenias and/or autoimmune disorders. As patients often do not have symptoms warranting therapy upfront, surveillance is often employed. Common frontline therapies include cyclosphosphamide, methotrexate or cyclosporine A, however, no controlled trials or retrospective analyses have demonstrated one superior therapeutic strategy. Mechanisms of pathogenesis and survival have been identified that include abnormalities in the cell surface receptors halting apoptotic signals, dysregulation of prosurvival and apoptotic signaling pathways, and somatic mutations of the STAT3 and STAT5b genes, among others. Investigating novel therapies that target pathways shared by other neoplastic processes, as well as the identification of new agents directed toward the aberrant cellular mechanisms of large granular lymphocyte leukemia, are fundamental to moving from empiric chemotherapy to targeted therapies in the future.

Advances in diagnosis and treatment of large granular lymphocyte syndrome

PURPOSE OF REVIEW

Large granular lymphocyte (LGL) syndrome comprises a clonal spectrum of T-cell and natural killer (NK)-cell LGL lymphoproliferative disorders associated with neutropenia. This review presents advances in diagnosis and therapy of LGL syndrome.

RECENT FINDINGS

Due to the lack of a single unique genetic or phenotypic feature and clinicopathological overlap between reactive and neoplastic entities, accurate LGL syndrome diagnosis should be based on the combination of morphologic, immunophenotypic, and molecular studies as well as clinical features. For diagnosis and monitoring of LGL proliferations, it is essential to perform flow cytometric blood and/or bone marrow analysis using a panel of monoclonal antibodies to conventional and novel T-cell and NK-cell antigens such as NK-cell receptors and T-cell receptor β-chain variable region families together with TCR gene rearrangement studies. Treatment of symptomatic cytopenias in patients with indolent LGL leukemia is still based on immunosuppressive therapy. Treatment with purine analogs and alemtuzumab may be considered as an alternative option.

SUMMARY

Progress in understanding the pathogenetic mechanisms of these entities, especially resistance of clonal LGLs to apoptosis, due to constitutive activation of survival signaling pathways, has its impact on identification of potential molecular therapeutic targets.

Large granular lymphocytic leukemia presenting late after solid organ transplantation: a case series of four patients and review of the literature

Post-transplantation lymphoproliferative disorder (PTLD) is a significant complication of solid organ transplantation. Most PTLD is of the B-cell subtype, although T-cell subtype PTLD uncommonly occurs. T-cell PTLDs are usually aggressive neoplasms and shorten patient and allograft survivals significantly. We present a single-center case series of 4 patients who developed T-cell large granular lymphocytic (LGL) leukemia, a rare T-cell PTLD characterized by large granular lymphocytes that have characteristic azurophilic granules and a highly variable clinical course.

The pathogenesis and treatment of large granular lymphocyte leukemia

Large granular lymphocyte (LGL) leukemia is a spectrum of rare lymphoproliferative diseases of T lymphocytes and natural killer cells. These diseases frequently present with splenomegaly, neutropenia, and autoimmune diseases like rheumatoid arthritis. LGL leukemia is more commonly of a chronic, indolent nature; however, rarely, they have an aggressive course. LGL leukemia is thought to arise from chronic antigen stimulation, which drives long-term cell survival through the activation of survival signaling pathways and suppression of pro-apoptotic signals. These include Jak-Stat, Mapk, Pi3k-Akt, sphingolipid, and IL-15/Pdgf signaling. Treatment traditionally includes immunosuppression with low dose methotrexate, cyclophosphamide, and other immunosuppressive agents; however, prospective and retrospective studies reveal very limited success. New studies surrounding Jak-Stat signaling suggest this may reveal new avenues for LGL leukemia therapeutics.

Treatment of T-cell large granular lymphocyte leukemia with cyclosporine A: experience in a Chinese single institution

T-cell large granular lymphocyte leukemia (T-LGLL) is a rare chronic lymphoproliferative disorder. Available reported data on the treatment regimens of this disease are variable and limited due to low number of patients. We analyzed the efficiency of cyclosporine A (CsA) in the treatment of 28 patients with T-LGLL. The overall response rate (ORR) was 82.1% with hematologic complete remission (HCR) rate of 57.1%. The median time to response (TTR) was 1.8 months and treatment duration with CsA-based regimens was 34.5 months. CsA shows low and manageable toxicity during treatment. Twenty-one patients survived with a median follow-up time of 42.0 months. Our results indicate that CsA is efficacious and safe in the treatment of T-LGLL.

Autoimmune manifestations in large granular lymphocyte leukemia

Large granular lymphocyte (LGL) leukemia features a group of indolent lymphoproliferative diseases that display a strong association with various autoimmune conditions. Notwithstanding, these autoimmune conditions have not been comprehensively characterized or systematized to date. As a result, their clinical implications remain largely unknown. The authors offer a comprehensive review of the existing literature on various autoimmune conditions documented in the course of T-cell LGL (T-LGL) leukemia. Though some of them are thought be secondary to the LGL leukemia, others could be primary and might even play a role in its pathogenesis. A considerable clinico-laboratory overlap between T-LGL leukemia associated with rheumatoid arthritis and Felty's syndrome suggests that they are just different eponyms for the same clinical entity.

Pathophysiologic mechanisms and management of neutropenia associated with large granular lymphocytic leukemia

Large granular lymphocyte (LGL) syndrome includes a spectrum of clonal T cell and natural killer cell chronic lymphoproliferative disorders. These conditions are thought to arise from chronic antigenic stimulation, while the long-term survival of the abnormal LGLs appears to be sustained by resistance to apoptosis and/or impaired survival signaling. T-cell LGL (T-LGL) leukemia is the most common LGL disorder in the Western world. Despite its indolent course, the disease is often associated with neutropenia, the pathogenesis of which is multifactorial, comprising both humoral and cytotoxic mechanisms. This article addresses the pathogenesis of T-LGL leukemia and natural killer cell chronic lymphoproliferative disorder, as well as that of T-LGL leukemia-associated neutropenia. Furthermore, as symptomatic neutropenia represents an indication for initiating treatment, available therapeutic options are also discussed.

Clinical, morphologic, immunophenotypic, and molecular cytogenetic assessment of CD4-/CD8-γδ T-cell large granular lymphocytic leukemia

γδ T-cell large granular lymphocytic (T-LGL) leukemia of the CD4-/CD8- subtype is rare, and data are limited in the literature. This study evaluated the clinical, morphologic, immunophenotypic, and molecular cytogenetic features of 7 cases of CD4-/CD8- γδ T-LGL leukemia. Although this variant shares several clinical and morphologic features with the more common T-LGL leukemias, the incidences of autoimmune hemolytic anemia and pure red cell aplasia are higher. Another striking feature observed in our study was the lack of increased large granular lymphocytes in the peripheral blood in the majority of cases despite prominent bone marrow or splenic involvement. CD4-/CD8- γδ T-LGL leukemia also displays an immunophenotype and pattern of splenic involvement overlapping with hepatosplenic T-cell lymphoma. Clinically, this variant of T-LGL leukemia shows an overall indolent course, but treatment is often required in the initial stages of the disease. Awareness of these features is important for early recognition and accurate diagnosis of patients with CD4-/CD8- γδ T-LGL leukemia.

T-cell and natural killer-cell large granular lymphocyte leukemia neoplasias

Large granular lymphocyte (LGL) leukemia is a rare disorder of cytotoxic lymphocytes. LGL cells play an integral role in the immune system and are divided into two major lineages of CD3(-)natural killer (NK) cells and CD3(+) T cells that circulate throughout the blood in search of infected cells, in which they will make contact through a receptor ligand and induce cell death. LGL cells are also programmed to undergo apoptosis after contact with an infected target cell; however, they continue to survive in individuals with LGL leukemia. This unchecked proliferation and cytotoxicity of LGLs in patients results in autoimmunity or malignancy. Rheumatoid arthritis is the most common autoimmune condition seen in individuals with LGL leukemia; however, LGL leukemia is associated with a wide spectrum of other autoimmune diseases. Patients may also suffer from other hematological conditions including hemolytic anemia, pure red cell aplasia, and neutropenia, which lead to recurrent bacterial infections. Currently, the only established treatment involves a low dose of an immunosuppressive regimen with methotrexate, in which 40-50% of patients are either resistant or do not respond. In order to establish new therapeutics it is important to understand the current state of LGL leukemia both in the clinic and in basic research.

Guidelines for the management of mature T-cell and NK-cell neoplasms (excluding cutaneous T-cell lymphoma)

The peripheral T-cell neoplasms are a biologically and clinically heterogeneous group of rare disorders that result from clonal proliferation of mature post-thymic lymphocytes. Natural killer (NK) cell neoplasms are included in this group. The World Health Organization classification of haemopoietic malignancies has divided this group of disorders into those with predominantly leukaemic (disseminated), nodal, extra-nodal or cutaneous presentation. They usually affect adults and are more commonly reported in males than in females. The median age at diagnosis is 61 years with a range of 17-90 years. Although some subtypes may follow a relatively benign protracted course most have an aggressive clinical behaviour and poor prognosis. Excluding anaplastic lymphoma kinase (ALK)-positive anaplastic large cell lymphoma (ALCL), which has a good outcome, 5-year survival for other nodal and extranodal T-cell lymphomas is about 30%. Most patients present with unfavourable international prognostic index scores (>3) and poor performance status. The rarity of these diseases and the lack of randomized trials mean that there is no consensus about optimal therapy for T- and NK-cell neoplasms and recommendations in this guideline are therefore based on small case series, phase II trials and expert opinion.

Oral manifestations of T-cell large granular lymphocytic leukemia: a case report

Background

T-cell large granular lymphocytic (T-LGL) leukemia is a rare, chronic, often indolent lymphoproliferative disorder of mature T cells (CD3+). Severe neutropenia and other cytopenias are common features in patients with T-LGL leukemia and may cause infections, thus representing a major cause of morbidity in this disease. Immunosuppressive therapy with low-dose regimes of methotrexate, cyclophosphamide, corticosteroids or cyclosporine A is the treatment of choice. Amongst the variety of T-LGL leukemia complications, oral manifestations such as ulcers have been rarely reported. The purpose of this paper is to report a case of T-cell large granular lymphocyte leukemia with oral manifestations and to discuss their pathogenesis and management.

Methods

In the present case, a 65 year old female with a two-month history of diagnosed T-LGL leukemia presented with oral lesions, including ulcerations on the ventral tongue and soft palate as well as swollen, erythematous and ulcerated gingiva. The patient was under treatment with methotrexate, granulocyte colony-stimulating factor (G-CSF) and erythropoietin.

Results

Considering patients' medical history and clinical appearance of the lesions, a clinical diagnosis of a neutropenic ulcer of the tongue was established. The oral lesions resolved after treatment with antibiotics, topical steroids and antiseptics combined with improvement of the hematological condition. The pertinent literature related to T-LGL leukemia ethiopathology, diagnostics and treatment was discussed.

Conclusions

Although rare, T-cell large granular lymphocytic leukemia should be included in the list of lymphoproliferative disorders, which may present with oral manifestations as a result of the disease and its treatment complications.

How I treat LGL leukemia

Large granular lymphocyte (LGL) leukemia is characterized by a clonal expansion of either CD3(+) cytotoxic T or CD3(-) NK cells. Prominent clinical features of T-LGL leukemia include neutropenia, anemia and rheumatoid arthritis (RA). The terminal effector memory phenotype (CD3(+)/CD45RA(+)/CD62L(-)CD57(+)) of T-LGL suggests a pivotal chronic antigen-driven immune response. LGL survival is then promoted by platelet-derived growth factor and interleukin-15, resulting in global dysregulation of apoptosis and resistance to normal pathways of activation-induced cell death. These pathogenic features explain why treatment of T-LGL leukemia is based on immunosuppressive therapy. The majority of these patients eventually need treatment because of severe or symptomatic neutropenia, anemia, or RA. No standard therapy has been established because of the absence of large prospective trials. The authors use low-dose methotrexate initially for T-LGL leukemia patients with neutropenia and/or RA. We recommend either methotrexate or oral cyclophosphamide as initial therapy for anemia. If treatment is not successful, patients are switched to either the other agent or cyclosporine. The majority of patients experience an indolent clinical course. Deaths infrequently occur because of infections related to severe neutropenia. As there are no curative therapeutic modalities for T-LGL leukemia, new treatment options are needed.

Immunosuppressive therapies in the management of immune-mediated marrow failures in adults: where we stand and where we are going

Immunosuppression is a key treatment strategy for aplastic anaemia (AA) and the related immune-mediated bone marrow failure syndromes (BMFS). For the last 20 years the standard immunosuppressive regimen for AA patients has been anti-thymocyte globulin (ATG) plus ciclosporin A (CyA), which results in response rates ranging between 50% and 70%, and even higher overall survival. However, primary and secondary failures after immunosuppressive therapy remain frequent, and to date all attempts aiming to overcome this problem have been unfruitful. This article reviews the state of the art of current immunosuppressive therapies for AA, focusing on open questions linked to standard immunosuppressive treatment, and on experimental immunosuppressive strategies which could lead to future improvement of current treatments. Specific immunosuppressive strategies employed for other BMFS, such as lineage-restricted marrow failures, myelodysplastic syndromes and large granular lymphocyte leukaemia-associated cytopenias, are also briefly discussed.

How I diagnose and treat splenic lymphomas

The incidental finding of an isolated splenomegaly during clinical assessment of patients evaluated for unrelated causes has become increasingly frequent because of the widespread use of imaging. Therefore, the challenging approach to the differential diagnosis of spleen disorders has emerged as a rather common issue of clinical practice. A true diagnostic dilemma hides in distinguishing pathologic conditions primarily involving the spleen from those in which splenomegaly presents as an epiphenomenon of hepatic or systemic diseases. Among the causes of isolated splenomegaly, lymphoid malignancies account for a relevant, yet probably underestimated, number of cases. Splenic lymphomas constitute a wide and heterogeneous array of diseases, whose clinical behavior spans from indolent to highly aggressive. Such a clinical heterogeneity is paralleled by the high degree of biologic variation in the lymphoid populations from which they originate. Nevertheless, the presenting clinical, laboratory, and pathologic features of these diseases often display significant overlaps. In this manuscript, we present our approach to the diagnosis and treatment of these rare lymphomas, whose complexity has been so far determined by the lack of prospectively validated prognostic systems, treatment strategies, and response criteria.

Large granular lymphocyte leukemia

Clonal diseases of large granular lymphocytes (LGLs) represent a spectrum of clinically rare lymphoproliferative malignancies arising from either mature T-cell (CD3(+)) or natural killer (NK)-cell (CD3(-)) lineages. The clinical behavior of these disorders ranges from indolent to very aggressive. Patients with symptomatic indolent T-cell or NK-cell LGL leukemia are usually treated with immunosuppressive therapies; in contrast, aggressive T-cell or NK-cell LGL leukemias require intensive chemotherapy regimens. Novel targeted therapies are currently being tested in clinical studies.

Analysis of a French cohort of patients with large granular lymphocyte leukemia: a report on 229 cases

BACKGROUND

Large granular lymphocyte leukemia is a rare lymphoproliferative disorder associated with autoimmune diseases and impaired hematopoiesis. This study describes the clinical and biological characteristics of 229 patients with T-cell or NK-cell large granular lymphocyte leukemia.

DESIGN AND METHODS

The diagnosis was based on a large granular lymphocyte expansion (> 0.5x10(9)/L) lasting more than 6 months. Monoclonal T-cell receptor gamma gene rearrangement was detected in all the cases of T-cell large granular lymphocyte leukemia. Patients with chronic NK-cell lymphocytosis had an indolent disease, while those with multiorgan large granular lymphocyte infiltration and an aggressive clinical disease were considered to have NK-cell large granular lymphocyte leukemia.

RESULTS

The diagnosis of T-cell large granular lymphocyte leukemia was confirmed in 201 cases, chronic NK-cell lymphocytosis in 27 cases and NK-cell large granular lymphocyte leukemia in one case. Associated autoimmune diseases or other neoplasms were present in 74 and 32 cases, respectively. One hundred patients (44%) required treatment, mainly for neutropenia-associated infections (n=45), symptomatic autoimmune diseases (n =24), transfusion-dependant anemia (n=18), and other causes (n=13). Patients were treated with steroids (n= 33), methotrexate (n=62), cytoxan (n=32), or cyclosporine (n=24) either as first-, second-, third- or fourth-line therapy. The overall response rate at 3 months and complete response rate for the various treatments were as follows: steroids (12% and 3%), methotrexate (55% and 21%), cytoxan (66% and 47%), cyclosporine (21% and 4%), respectively. Four out of 13 patients responded to splenectomy. Eleven out of 15 patients responded to cytoxan after methotrexate treatment had failed. The mean number of treatments was 3.4 (range, 1-7). There were 15 large granular lymphocyte leukemia-related deaths.

CONCLUSIONS

Patients with T-cell large granular lymphocyte leukemia and chronic NK-cell lymphocytosis have similar clinical and biological features and responses to treatment. First-line therapy with cytoxan should be tested in a prospective trial.

T-cell large granular lymphocyte leukemia: an Asian perspective

To characterize T-cell large granular leukemia in Asia, 22 Chinese patients from a single institute were reported, together with an analysis of 88 Asian and 272 Western patients identified from the literature. In our cohort, anemia due to pure red cell aplasia (PRCA) occurred in 15/22 (68%) of cases, being the most common indication for treatment. Neutropenia was only found in 8/22 (36%) cases, and recurrent infections, the most important clinical problem in Western patients, were not observed. None of our cases presented with rheumatoid arthritis. These clinical features were consistently observed when compared with the 88 other Asian patients. Combined data from our cohort and other Asian cases showed that Asian patients, compared with Western patients, had more frequent anemia (66/110, 60% versus 113/240, 47%; p=0.044), attributable to a much higher incidence of PRCA (52/110, 47% versus 6/143, 4%; p<0.001). However, Western patients presented more frequently than Asian patients with neutropenia (146/235, 62% versus 33/110, 30%; p<0.001) and splenomegaly (99/246, 40% versus 16/110, 15%; p< 0.001). Notably, Western patients were about eight to ten times more likely than Asian patients to have rheumatoid arthritis (73/272, 27% versus 4/106, 4%; p<0.001) and recurrent infections (81/272, 30% versus 3/107, 3%; p<0.001). These clinicopathologic differences have important implications on disease pathogenesis and treatment.

[Large granular lymphocytic leukaemia]

BACKGROUND

Large granular lymphocytic leukaemia (LGL-leukaemia) is considered a rare disease. LGL-leukaemia is usually of the T-cell type, but a minority displays an NK-cell phenotype. Incidence and prevalence are unknown.

MATERIAL AND METHODS

We identified patients with LGL-leukaemia (with well-defined diagnostic criteria) diagnosed at Rikshospitalet University Hospital between 01.10.2001 and 31.12.2007. Their medical records were assessed retrospectively.

RESULTS

LGL-leukaemia was diagnosed in 52 patients, 26 women and 26 men, median age of 59 (26 - 86) years, during the study period. The leukaemia displayed NK-cell phenotype in one patient and T-cell phenotype in the remaining 51 patients. Slightly more than one third of the patients were asymptomatic. Cytopenia, mostly neutropenia, was usually the cause of the clinical phenotype in symptomatic patients. Co-morbidity with autoimmune disease was common, and we also found a high prevalence of clonal B-cell disease (17 %).

INTERPRETATION

Our data support the notion that LGL-leukaemia is under-diagnosed. Unexplained cytopenias should suggest the possibility of LGL-leukaemia, and appropriate diagnostic measures should be undertaken. An early diagnosis may save patients an extensive and unnecessary diagnostic work-up and ensure that a simple and effective treatment is offered.

Diagnosis and management of acquired pure red cell aplasia

Pure red cell aplasia is a syndrome characterized by a severe normocytic anemia, reticulocytopenia, and absence of erythroblasts from an otherwise normal bone marrow. Although the causes and natural course of this syndrome are variable and although the anemia in some patients can be managed by treatment of an underlying inflammatory or neoplastic disease, the pathogenesis of a large number of cases is autoimmune, including those associated with thymoma, and are best managed with immunosuppressive therapy.

T-cell large granular lymphocytic (T-LGL) leukemia: a single institution experience

BACKGROUND

T-cell large granular lymphocytic (T-LGL) leukemia is a rare lymphoproliferative disease which usually affects elderly people. The clinical course of T-LGL leukemia is generally indolent, with lymphocytosis and splenomegaly in 20-50% patients, hepatomegaly in 5-20% of patients, and less commonly, lymphadenopathy. T-LGL leukemia is associated with immunological abnormalities: rheumatoid factor with or without rheumatoid arthritis (RA), Coombs positive hemolytic anemia, idiopathic thrombocytopenic purpura (ITP), pure red cell aplasia (PRCA), positive anti-nuclear antibodies (ANA), anti-neutrophil cytoplasmic antibodies (ANCA), hypogammaglobulinemia, and polyclonal hypergammaglobulinemia. Aim To compare clinical and laboratory features of T-LGL leukemia patients and their responses to different chemotherapy regimens.

METHODS

Six patients (3 males and 3 females) with T-LGL leukemia were analyzed. The diagnosis was based on accepted morphologic criteria, immunophenotype, and polymerase chain reaction (PCR) detection of T-cell receptor (TCR) gene rearrangements.

RESULTS

All patients exhibited lymphocytosis, mainly with unusual morphologies, splenomegaly, and elevated serum lactate dehydrogenase (LDH). Three patients were treated with a Fludarabine-Cyclophosphamide (FC) combination as initial therapy while three patients received CHOP. Two patients received more than one treatment regimen. One patient died due to T-LGL leukemia in first year after diagnosis, one patient died 4 years after diagnosis, two patients interrupted their treatment, and two patients are still alive.

CONCLUSIONS

Further prospective studies are needed for establishing a gold standard therapy for T-LGL leukemia.

Pathobiology of mature T-cell lymphomas

Mature T- and natural killer (NK)-cell neoplasms are relatively rare forms of leukemia/lymphoma. The diagnosis of these entities is often difficult, necessitating extensive immunophenotypic, molecular, and genetic testing. Despite the accumulating information on the pathobiology of these neoplasms, in many cases the prognosis remains poor. This article presents an updated view of the morphologic, immunophenotypic, genetic, and molecular characteristics of the mature T- and NK-cell neoplasms. For a better understanding of this complex topic, the development of normal T and NK cells is briefly discussed. The presentation of the characteristic features of the neoplasms in the 2008 World Health Organization classification of hematopoietic neoplasms includes advances in the understanding of the pathobiology of each diagnostic category.