Characteristic appearances of the bone marrow in T-cell large granular lymphocyte leukaemia

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.

T-large Granular Lymphocytic Leukemia: A Rare Diagnosis in a Young Woman With Fever, Necrotic Skin Lesions and Cytopenias

T-large granular lymphocytic leukemia (T-LGLL) is a rare lymphoproliferative disorder. The diagnosis is established by identifying an abnormally high number of clonal granular T lymphocytes in the peripheral blood and eventually in the bone marrow, in cases with medullary infiltration. The majority of patients present with symptoms related to neutropenia and this condition may be associated with autoimmune diseases in up to a third of cases. The authors describe the case of a 26-year-old patient admitted with subacute high fever and bullous dermatitis with necrotic lesions with central bullae. Analytically, she presented anemia and leukopenia with severe neutropenia of 200 cells/L. Skin lesions were compatible with ecthyma and the skin biopsy revealed aspects compatible with leukocytoclastic vasculitis. The myelogram and bone biopsy revealed hypoplasia of the myeloid line and a pathological T population of CD8+, TIA-1+ and granzyme B+, which were associated with compatible flow cytometry (CD3+, T-cell receptor (TCR) Alpha-Beta+, CD5+, CD2+, with loss of CD7 antigen expression) established the diagnosis of T-LGLL. The patient had a favorable evolution, with cytopenias almost returning to normal after two months. She began follow-up at a Hematology Reference Center, remaining asymptomatic without specific treatment considering the indolent course of the disease.

Large granular lymphocyte leukemia: An indolent clonal proliferative disease associated with an array of various immunologic disorders

Large granular lymphocyte leukemia (LGLL) is a chronic lymphoproliferative disorder characterized by the proliferation of T or NK cytotoxic cells in the peripheral blood, the spleen and the bone marrow. Neutropenia leading to recurrent infections represents the main manifestation of LGLL. One specificity of LGLL is its frequent association with auto-immune disorders, among them first and foremost rheumatoid arthritis, and other hematologic diseases, including pure red cell aplasia and bone marrow failure. The large spectrum of manifestations and the classical indolent course contribute to the diagnosis difficulties and the frequency of underdiagnosed cases. Of importance, the dysimmune manifestations disappear with the treatment of LGLL as the blood cell counts normalize, giving a strong argument for a pathological link between the two entities. The therapeutic challenge results from the high rate of relapses following the first line of immunosuppressive drugs. New targeted agents, some of which are currently approved in autoimmune diseases, appear to be relevant therapeutic strategies to treat LGLL, by targeting key activated pathways involved in the pathogenesis of the disease, including JAK-STAT signaling.

Retrospective Study of T Cell Leukaemia (Large Granular Lymphocyte Variant) in Dogs Associated with Suspected Immune-Mediated Cytopaenia(s) in the Absence of Peripheral Lymphocytosis

Canine chronic large granular lymphocyte (LGL) leukaemia is commonly characterised by moderate to marked lymphocytosis but not neutropaenia. In humans, LGL leukaemia is often associated with autoimmune disorders, including immune-mediated cytopaenias (mainly neutropaenia). This presentation is rare in dogs. The aim of this retrospective study was to describe the clinical characteristics, treatments, and outcomes of dogs with chronic LGL leukaemia with suspected immune-mediated cytopaenia. Six dogs with a median age of 4.5 years (range 2-8 years) were included in the study. The most common presenting signs were pyrexia and lethargy. All dogs had severe neutropaenia (median neutrophil count 0.07 × 10⁹/L), three had thrombocytopaenia (median platelet count 66 × 10⁹/L), and one had anaemia (HCT 0.32 L/L). In all dogs, bone marrow cytology revealed infiltration of granular T lymphocytes; PARR analysis confirmed clonality in four, and bone marrow flow cytometry identified CD3+ CD8+ neoplastic cells in two cases. All patients received systemic chemotherapy, and the cytopaenias resolved after 1-19 weeks. Two dogs were euthanised 133 and 322 days after diagnosis, two were lost to follow-up after 224 and 357 days, and two were alive at 546 and 721 days. A subset of LGL leukaemia in dogs is associated with immune-mediated cytopaenia and has a unique clinical presentation.

All that glitters is not LGL Leukemia

LGL disorders are rare hematological neoplasias with remarkable phenotypic, genotypic and clinical heterogeneity. Despite these constraints, many achievements have been recently accomplished in understanding the aberrant pathways involved in the LGL leukemogenesis. In particular, compelling evidence implicates STAT signaling as a crucial player of the abnormal cell survival. As interest increases in mapping hematological malignancies by molecular genetics, the relevance of STAT gene mutations in LGL disorders has emerged thanks to their association with discrete clinical features. STAT3 and STAT5b mutations are recognized as the most common gain-of-function genetic lesions up to now identified in T-LGL leukemia (T-LGLL) and are actually regarded as the hallmark of this disorder, also contributing to further refine its subclassification. However, from a clinical perspective, the relationships between T-LGLL and other borderline and overlapping conditions, including reactive cell expansions, clonal hematopoiesis of indeterminate potential (CHIP) and unrelated clonopathies are not fully established, sometimes making the diagnosis of T cell malignancy challenging. In this review specifically focused on the topic of clonality of T-LGL disorders we will discuss the rationale of the appropriate steps to aid in distinguishing LGLL from its mimics, also attempting to provide new clues to stimulate further investigations designed to move this field forward.

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.

Toward a Better Classification System for NK-LGL Disorders

Large granular lymphocytic leukemia is a rare lymphoproliferative disorder characterized by a clonal expansion of T-lineage lymphocyte or natural killer (NK) cells in 85 and 15% of cases respectively. T and NK large granular leukemia share common pathophysiology, clinical and biological presentation. The disease is characterized by cytopenia and a frequent association with autoimmune manifestations. Despite an indolent course allowing a watch and wait attitude in the majority of patients at diagnosis, two third of the patient will eventually need a treatment during the course of the disease. Unlike T lymphocyte, NK cells do not express T cell receptor making the proof of clonality difficult. Indeed, the distinction between clonal and reactive NK-cell expansion observed in several situations such as autoimmune diseases and viral infections is challenging. Advances in our understanding of the pathogenesis with the recent identification of recurrent mutations provide new tools to prove the clonality. In this review, we will discuss the pathophysiology of NK large granular leukemia, the recent advances in the diagnosis and therapeutic strategies.

Neutropenia and Large Granular Lymphocyte Leukemia: From Pathogenesis to Therapeutic Options

Large granular lymphocyte leukemia (LGLL) is a rare lymphoproliferative disorder characterized by the clonal expansion of cytotoxic T-LGL or NK cells. Chronic isolated neutropenia represents the clinical hallmark of the disease, being present in up to 80% of cases. New advances were made in the biological characterization of neutropenia in these patients, in particular STAT3 mutations and a discrete immunophenotype are now recognized as relevant features. Nevertheless, the etiology of LGLL-related neutropenia is not completely elucidated and several mechanisms, including humoral abnormalities, bone marrow infiltration/substitution and cell-mediated cytotoxicity might cooperate to its pathogenesis. As a consequence of the multifactorial nature of LGLL-related neutropenia, a targeted therapeutic approach for neutropenic patients has not been developed yet; moreover, specific guidelines based on prospective trials are still lacking, thus making the treatment of this disorder a complex and challenging task. Immunosuppressive therapy represents the current, although poorly effective, therapeutic strategy. The recent identification of a STAT3-mediated miR-146b down-regulation in neutropenic T-LGLL patients emphasized the pathogenetic role of STAT3 activation in neutropenia development. Accordingly, JAK/STAT3 axis inhibition and miR-146b restoration might represent tempting strategies and should be prospectively evaluated for the treatment of neutropenic LGLL patients.

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.

T-Cell Large Granular Lymphocytic Leukemia - Case Reports

SUMMARY – T-cell large granular lymphocytic leukemia (T-LGLL) is an uncommon but probably underdiagnosed disease caused by clonal proliferation of large granular lymphocytes. Diagnosis is typically based on the high number of morphologically characteristic lymphoid cells and finding of an abnormal immunophenotype by flow cytometry. Because of its relatively indolent clinical behavior, observation is often an appropriate therapy. Here we present a case of a 53-year-old male admitted to the hospital because of abdominal pain. Blood examination revealed mild mycrocitic anemia and multiplied lactate dehydrogenase level. Abdominal ultrasound showed splenomegaly of 16 cm, with no lymphadenopathy. Fine needle aspiration of bone marrow revealed hypocellular marrow with 50% of atypical lymphoid cells. There were 81% of atypical medium sized granular lymphocytes with irregularly shaped nuclei in peripheral blood, so the cytologic diagnosis was lymphoproliferative process. Bone marrow biopsy showed nodular and interstitial proliferation of small, partially atypical T lymphocytic cells positive for CD2, CD3, CD5, CD8, granzyme and TIA, and negative for hairy cell markers, CD10, MUM 1, bcl 1, CD4 and CD56. The finding was consistent with T-LGLL. Due to splenomegaly, the patient was treated with cyclosporine and gradually reduced dose of corticosteroids, leading to regression of splenomegaly and normalization of lactate dehydrogenase level.

Large granular lymphocytic leukemia. Current diagnostic and therapeutic approaches and novel treatment options

INTRODUCTION

Large granular lymphocytic leukemia (LGLL) is a low grade lymphoproliferative disorder characterized by the clonal proliferation of large granular lymphocytes (LGL) and recognised by the WHO. The diagnosis and management of these patients is challenging due to the limited information from prospective studies. Guidelines for front-line therapy have not been established. The prognosis is favourable with median overall survivals greater than 10 years. Areas covered: This manuscript is a review of the clinical features, diagnosis, pathogenesis and, in particular, the various available therapeutic options for this rare lymphoid leukemia. A systematic literature search using electronic PubMed database has been carried out. Expert commentary: A watch and wait strategy without therapeutic intervention is recommended in asymptomatic patients. The immunomodulators methotrexate, cyclophosphamide and cyclosporin are the most commonly used drugs in the routine practice with responses ranging from 50 to 65% and without evidence of cross-resistance among them. Purine analogs such as 2´deoxycoformycin and fludarabine alone or in combination may be indicated in patients with bulky and/or widespread disease. Trials using monoclonal antibodies such as Alemtuzumab and agents targeting the disrupted JAK/STAT pathway in LGLL such as JAK-3 inhibitors are promising particularly in a relapse setting.

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.

Pathology of T-cell lymphomas: diagnosis and biomarker discovery

T-cell lymphomas are a group of predominantly rare hematologic malignancies that tend to recapitulate different stages of T-cell development, in a similar way that B-cell lymphomas do. As opposed to B-cell lymphomas, the understanding of the biology and the classification of T-cell lymphomas are somewhat rudimentary, and numerous entities are still included as 'provisional categories' in the World Health Classification of hematolopoietic malignancies. A relevant and useful classification of these disorders have been difficult to accomplish because of the rarity nature of them, the relative lack of understanding of the molecular pathogenesis, and their morphological and immunophenotypical complexity. Overall, T-cell lymphomas represent only 15 % of all non-Hodgkin lymphomas. This review is focused on addressing the current status of the categories of mature T-cell leukemias and lymphomas (nodal and extranodal) using an approach that incorporates histopathology, immunophenotype, and molecular understanding of the nature of these disorders, using the same philosophy of the most recent revised WHO classification of hematopoietic malignancies.

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.

Distinguishing T-cell Large Granular Lymphocytic Leukemia from Reactive Conditions: Laboratory Tools and Challenges in Their Use

This article focuses on the challenges of diagnosing T-cell large granular leukemia and distinguishing it from benign reactive conditions, as well as more aggressive neoplasms of cytotoxic lymphocytes. No single laboratory method is sufficient to make the diagnosis, but instead a combination of flow cytometry, genetic studies, and bone marrow immunohistochemistry must be used.

Fibrosis and subsequent cytopenias are associated with basic fibroblast growth factor-deficient pluripotent mesenchymal stromal cells in large granular lymphocyte leukemia

Cytopenias occur frequently in systemic lupus erythematosus, rheumatoid arthritis, Felty's syndrome, and large granular lymphocyte (LGL) leukemia, but the bone marrow microenvironment has not been systematically studied. In LGL leukemia (n = 24), retrospective analysis of bone marrow (BM) histopathology revealed severe fibrosis in 15 of 24 patients (63%) in association with the presence of cytopenias, occurrence of autoimmune diseases, and splenomegaly, but was undetectable in control cases with B cell malignancies (n = 11). Fibrosis severity correlated with T cell LGL cell numbers in the BM, but not in the periphery, suggesting deregulation is limited to the BM microenvironment. To identify fibrosis-initiating populations, primary mesenchymal stromal cultures (MSCs) from patients were characterized and found to display proliferation kinetics and overabundant collagen deposition, but displayed normal telomere lengths and osteoblastogenic, chondrogenic, and adipogenic differentiation potentials. To determine the effect of fibrosis on healthy hematopoietic progenitor cells (HPCs), bioartificial matrixes from rat tail or purified human collagen were found to suppress HPC differentiation and proliferation. The ability of patient MSCs to support healthy HSC proliferation was significantly impaired, but could be rescued with collagenase pretreatment. Clustering analysis confirmed the undifferentiated state of patient MSCs, and pathway analysis revealed an inverse relationship between cell division and profibrotic ontologies associated with reduced basic fibroblast growth factor production, which was confirmed by ELISA. Reconstitution with exogenous basic fibroblast growth factor normalized patient MSC proliferation, collagen deposition, and HPC supportive function, suggesting LGL BM infiltration and secondary accumulation of MSC-derived collagen is responsible for hematopoietic failure in autoimmune-associated cytopenias in LGL leukemia.

A case of CD4(+)T-cell large granular lymphocytic leukemia

We report here a case of a 59-yr-old man with CD4⁺ T-cell large granular lymphocytic leukemia (T-LGL). Peripheral blood examination indicated leukocytosis (45×10⁹ cells/L) that consisted of 34% neoplastic lymphoid cells. Other laboratory results indicated no specific abnormalities except for serum antinuclear antibody titer (1:640), glucose (1.39 g/L), and hemoglobin A1c (7.7%) levels. Computed tomography indicated multiple small enlarged lymph nodes (<1 cm in diameter) in both the axillary and inguinal areas, a cutaneous nodule (1.5 cm in diameter) in the left suboccipital area, and mild hepatosplenomegaly. Bone marrow examination revealed hypercellular marrow that consisted of 2.4% neoplastic lymphoid cells. The neoplastic lymphoid cells exhibited a medium size, irregularly shaped nuclei, a moderate amount of cytoplasm, and large granules in the cytoplasm. Immunohistochemical analysis indicated CD3⁺, CD4⁺, T-cell receptor βF1⁺, granzyme B⁺, and TIA1⁺. Flow cytometric analysis of the neoplastic lymphoid cells revealed CD3+, cytoplasmic CD3⁺, CD4⁺, and CD7⁺. Cytogenetic analysis indicated an abnormal karyotype of 46,XY,inv(3)(p21q27),t(12;17)(q24.1;q21),del(13)(q14q22)[2]/46,XY[28]. The patient was diagnosed with CD4⁺ T-LGL and received chemotherapy (10.0 mg methotrexate). This is the second case of CD4⁺ T-LGL that has been reported in Korea.

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.

The gammadelta variant of T cell large granular lymphocyte leukemia is very similar to the common alphabeta type: report of two cases

The vast majority of cases of T cell large granular lymphocyte (T-LGL) leukemia have a CD3+, CD4-, CD8+ phenotype and express the alphabeta T cell receptor. Whether the rare gammadelta variant should be included in the same diagnostic category is currently unclear. Two well-characterized cases of gammadelta T-LGL leukemia were identified by our laboratory in 2007. These two cases and other reports of gammadelta T-LGL leukemia were compared with the common alphabeta variant. Other than more often being negative for both CD4 and CD8 (in about 35% to 40% of cases), the gammadelta variant of T-LGL leukemia is similar to the common alphabeta type in virtually all respects and should be included in the general category of T-LGL leukemia. However, it is important to exclude other more aggressive gammadelta T cell lymphoproliferative disorders.