NK/T-Cell Lymphomas: Pathobiology, Prognosis and Treatment Paradigm

The current World Health Organization (WHO) classification includes two types of natural killer (NK)-cell lymphomas: extranodal NK/T-cell lymphoma, nasal type (ENKL), and aggressive NK-cell leukemia (ANKL). These diseases are mostly endemic to East Asia and Latin America. The Epstein-Barr virus (EBV) is usually detected in tumor cells, suggesting that EBV plays an important role in lymphomagenesis. At the site of origin, ENKL can be divided into two major subtypes: nasal and extranasal diseases. The advanced disease presentation, highly aggressive clinical course, and poor prognosis of the latter are analogous to ANKL. It is well known that P-glycoprotein, which is a product of the multi-drug resistance (MDR1) gene, is expressed on neoplastic cells of ENKL or ANKL. This is a major cause of the refractoriness of malignant lymphoma to conventional chemotherapeutic regimens containing anthracycline. Recent studies, however, have identified that L-asparaginase-containing regimens, such as SMILE (steroid, methotrexate, ifosfamide, L-asparaginase and etoposide), are effective for ENKL. Considering the myelotoxicity of SMILE, its use in the treatment of ANKL needs some modifications, but this treatment scheme is promising in improving the prognosis of NK-cell lymphomas.     

FDG-PET in T-cell and NK-cell neoplasms.

BACKGROUND: A growing number of studies demonstrate the utility of (18)fluoro-2-deoxyglucose positron emission tomography (FDG-PET) in the management of malignant lymphoma. The results of FDG-PET, however, have not been studied extensively for T-cell and natural killer (NK)-cell neoplasms. PATIENTS AND METHODS: We retrospectively evaluated pretreatment FDG-PET scans in 41 patients with T/NK-cell neoplasms diagnosed according to the World Health Organization (WHO) classification. Histological subtypes frequently included were peripheral T-cell lymphoma, unspecified (PTCLu, n = 11), extranodal NK/T-cell lymphoma, nasal type (ENKL, n = 8), primary cutaneous anaplastic large cell lymphoma (C-ALCL, n = 5), and angioimmunoblastic T-cell lymphoma (AILT, n = 4). RESULTS: FDG-PET detected a lymphoma lesion in at least one site in 36 out of 41 patients. The positive rate was equally high in most histological subtypes except for cutaneous lymphomas: PTCLu 91%, ENKL 100%, C-ALCL 60%, AILT 100%. All the patients without an FDG-avid lesion had lesions restricted to skin. Among patients who had cutaneous lesions, only 50% had FDG-avid cutaneous lesions, all of which were tumorous. The positive rate of FDG-PET for bone marrow involvement was only 20%. CONCLUSION: T/NK-cell neoplasms incorporated in this study were generally FDG-avid except for cutaneous lesions and bone marrow involvement.     

Extranodal NK/T-cell lymphoma: diagnosis and treatment cues

Extranodal NK/T-cell lymphoma, nasal type (ENKL) is mostly endemic to East Asia. It predominantly occurs in the nasal or paranasal areas and less frequently in the skin. Most of the tumours show NK-cell, but rarely T-cell, phenotypes. The Epstein-Barr virus (EBV) genome can be usually detected in lymphoma cells. Geographic localization of ENKL matches the endemic distribution of EBV, suggesting that EBV plays an important role in lymphomagenesis. Originally, NK-cell and T-cell types were believed to present the same clinicopathologic characteristics, but recent data suggest more aggressive characteristics for the NK-cell phenotype. Although ENKL is sensitive to radiotherapy, it shows a poorer response to chemotherapeutic agents than other lymphomas due to expression of p-glycoprotein. Therefore, new therapeutic approaches must be considered. Several new clinical trials are now being conducted in East Asia.     

Large granular lymphocyte leukemia and natural killer cell leukemia/lymphomas

Opinion statement Natural killer (NK) cell leukemia and lymphoma represent rare conditions with heterogeneity of biologic behavior, prognosis, and responsiveness to therapy. The initial diagnosis of NK-cell malignancies can be difficult because of the lack of immunophenotypic clonality markers, morphologic heterogeneity, and a poor correlation between cytomorphology and prognosis. Therapeutic recommendations for NK-cell malignancies are derived from retrospective studies or case reports. Immature NK-cell malignancies often have aggressive behavior with poor prognosis, despite administration of acute myeloid leukemia or acute lymphocytic leukemia induction chemotherapy. The use of high-dose chemotherapy with stem cell rescue resulted in a prolonged survival in a small series of patients. NK-cell malignancies originating from cells with mature phenotypes form a spectrum of diseases with distinct prognosis. Patients with aggressive NK-cell leukemia invariably die within several months. Nasal and nasal-like NK/T-cell lymphomas with limited stage disease often respond to radiation therapy alone or combination with chemotherapy and radiation therapy, with 5-year disease-free survival rates ranging from 30% to 75%. Patients with T-cell large granular lymphocyte leukemia or chronic NK-cell lymphoproliferative disease of granular lymphocytes can have an indolent clinical course with long survival without therapy. However, approximately 66% of patients with T-cell large granular lymphocyte leukemia require lowdose chemotherapy with methotrexate or cyclophosphamide or immunosuppressive therapy with glucocorticosteroids or cyclosporine A for symptomatic cytopenias during the course of their disease.     

Prognostic factors for mature natural killer (NK) cell neoplasms: aggressive NK cell leukemia and extranodal NK cell lymphoma,nasal type

Background: Patients with natural killer (NK) cell neoplasms, aggressive NK cell leukemia (ANKL) and extranodal NK cell lymphoma, nasal type (ENKL), have poor outcome. Both diseases show a spectrum and the boundary of them remains unclear. The purpose of this study is to draw a prognostic model of total NK cell neoplasms.Patients and methods: We retrospectively analyzed 172 patients (22 with ANKL and 150 with ENKL). The ENKLs consisted of 123 nasal and 27 extranasal (16 cutaneous, 9 hepatosplenic, 1 intestinal and 1 nodal) lymphomas.Results: Complete remission rate for ENKL was 73% in stage I, but 15% in stage IV, which was consistent with that for ANKL (18%). The prognosis of ENKL was better than that of ANKL (median survival 10 versus 1.9 months, P < 0.0001) but was comparable when restricted to stage IV cases (4.0 months, P = 0.16). Multivariate analysis showed that four factors (non-nasal type, stage, performance status and numbers of extranodal involvement) were significant prognostic factors. Using these four variables, an NK prognostic index was successfully constructed. Four-year overall survival of patients with zero, one, two and three or four adverse factors were 55%, 33%, 15% and 6%, respectively.Conclusion: The current prognostic model successfully stratified patients with NK cell neoplasms with different outcomes.     

Diverging trends in incidence and mortality,and improved survival of non-Hodgkin's lymphoma,in the Netherlands, 1989–2007

BackgroundWe studied progress in the fight against non-Hodgkin's lymphoma (NHL) in the Netherlands by describing the changes in incidence, treatment, relative survival, and mortality during 1989–2007.Patients and methodsWe included all adult patients with NHL [i.e. all mature B-, T-, and natural killer (NK) cell neoplasms, with the exception of plasma cell neoplasms], newly diagnosed in the period 1989–2007 and recorded in the Netherlands Cancer Registry (n = 55 069). Regular mortality data were derived from Statistics Netherlands. Follow-up was completed up to 1 January 2009. Annual percentages of change in incidence, mortality, and relative survival were calculated.ResultsThe incidence of indolent B-cell and T- and NK-cell neoplasms rose significantly (estimated annual percentage change = 1.2% and 1.3%, respectively); incidence of aggressive B-cell neoplasms remained stable. Mortality due to NHL remained stable between 1989 and 2003, and has decreased since 2003. Five-year relative survival rates rose from 67% to 75%, and from 43% to 52%, respectively, for indolent and aggressive mature B-cell neoplasms, but 5-year survival remained stable at 48% for T- and NK-cell neoplasms.ConclusionsIn the Netherlands, incidence of indolent mature B-cell and mature T- and NK-cell neoplasms has increased since 1989 but remained stable for aggressive neoplasms. Survival increased for all mature B-cell neoplasms, preceding a declining mortality and increased prevalence of NHL (17 597 on 1 January 2008).     

CD56+ hematological neoplasms presenting in the skin: a retrospective analysis of 23 new cases and 130 cases from the literature.

BACKGROUND: The aim of this study was to define prognostic parameters and guidelines for diagnosis and treatment for CD56+ hematological neoplasms with first presentation in the skin. PATIENTS AND METHODS: The study group included 153 cases (23 new and 130 from the literature). According to the World Health Organization classification, the group included 15 nasal and 38 nasal-type natural killer (NK)/T-cell lymphomas, 63 blastic NK-cell lymphomas, 14 cutaneous CD30+ lymphoproliferations, 10 cases of myeloid leukemia, six cases of subcutaneous panniculitis-like T-cell lymphoma (SCPLTCL) and seven peripheral T-cell lymphomas, unspecified. RESULTS: In general, these CD56+ hematological neoplasms had a poor prognosis, with only 27% of patients alive after a median follow-up of 12 months. The median survival was 13 months. Nasal and nasal-type NK/T-cell lymphomas and CD56+ SCPLTCL had the worst prognosis, with a median survival of 5, 6 and 5 months, respectively. Only nasal-type NK/T-cell lymphomas presenting with only skin lesions had a somewhat better prognosis (median survival 27 months). In blastic NK-cell lymphomas (median survival 14 months), age 相似文献   

2008年版"世界卫生组织造血及淋巴组织肿瘤分类"指要

 2008年第4版"世界卫生组织造血及淋巴组织肿瘤分类"把该类肿瘤分列为12个项目,对分子生物学进展结合较多,基因、染色体改变均加入分类中。慢性骨髓增生性疾病改为骨髓增生性肿瘤,并将肥大细胞增多症（mastocytosis）归于此栏中。新增了伴有嗜酸细胞增多的髓系及淋巴细胞系恶性肿瘤及异常的PDDFRA、PDDFRB或FGFR1基因一栏。在骨髓增生异常综合征／骨髓增生性肿瘤（MDS／MPN）一栏中增加了伴环形铁粒幼细胞再生障碍性贫血并显著的血小板增多（RARS-T）（可能为一单独性疾病）。在骨髓增生异常综合征（MDS）一栏中分为一系或多系增生异常伴有一系或多系血细胞减少,并增添了儿童MDS。在急性髓系白血病及其有关前体细胞恶性肿瘤中,把髓系肉瘤（myeloid sarcoma）单独分类;新增加了唐氏综合征（Down syndrome）伴有的髓系增生疾病;新增加了母细胞性浆细胞样树突细胞肿瘤（blastic plasmacytoid dendretic cell neoplasm）。把系列不明的白血病（acute leukemia of ambiguous lineage）单列为一个项目,含6种白血病。在前体淋巴系肿瘤中分为B系及T系,淋巴母细胞性白血病／淋巴母细胞性淋巴瘤,其区别点在于骨髓中淋巴母细胞＞25 %,则诊断为淋巴细胞白血病[和急性髓系白血病（AML）不同,不设下限为20 %]。成熟B淋巴细胞系肿瘤分为39种,包括慢性淋巴细胞白血病、骨髓瘤、重链病、Burkitt淋巴瘤等,但不包括移植后淋巴细胞增生性疾病（PTLD）。成熟T淋巴细胞系和NK细胞系肿瘤栏目下列举了22种成熟T淋巴细胞系和NK细胞系恶性肿瘤。霍奇金淋巴瘤栏目下列举了6种霍奇金淋巴瘤。组织细胞和树突状细胞恶性肿瘤包括7种恶性肿瘤及播散性幼年型黄肉芽肿。移植后淋巴细胞增生性疾病（PTLD）被单独分类在一个栏目中,又分为５种类型。     

结外NK/T细胞淋巴瘤，鼻型的诊断与治疗进展

结外NK/T细胞淋巴瘤,鼻型（extranodal natural killer/T-cell lymphoma ,nasal type,ENKL）是非霍奇金淋巴瘤（non-hodgkin lymphoma,NHL ）的一种少见亚型,其侵袭性强且预后较差。ENKL 主要发生于鼻腔,其次是皮肤、胃肠道等。该病以血管的侵犯和组织破坏为主要病理学表现。ENKL 与EBV 的感染密切相关,EBV 水平对其辅助诊断有重要的意义。NK/T细胞表面的特征性标志物和特异性遗传学改变也可以帮助诊断该病。目前对于ENKL 的治疗尚在讨论中,虽然对早期患者采用放疗± 化疗联合治疗,以及对中晚期患者采用以左旋门冬酰胺酶为基础的化疗和造血干细胞移植得到了一定疗效,但仍需进一步的研究探索以形成规范的治疗原则。      

CD30 expression in extranodal natural killer/T-cell lymphoma,nasal type among 622cases of mature T-cell and natural killer-cell lymphoma at a single institution in South China

Background: Mature T-cell and natural killer (NK)-cell lymphomas compose a heterogeneous group of non-Hodgkinlymphomas, and extranodal NK/T-cell lymphoma, nasal type (ENKTL) is an aggressive subtype with sporadic CD30expression. However, the significance of CD30 expression in ENKTL is controversial. We aimed to classify a large cohortof patients with mature T-cell and NK-cell lymphomas according to the 2016 World Health Organization (WHO) classificationguidelines and to study the association between CD30 expression and prognosis of patients with ENKTL.Methods: We selected consecutive patients with mature T-cell and NK-cell lymphomas who attended our institutionbetween September 1, 2009 and August 31, 2013. We classified the lymphomas according to the 2016 revision of theWHO classification of lymphoid neoplasms, analyzed the associations between CD30 expression and clinicopathologicfeatures of ENKTL patients, and evaluated the prognostic implications of CD30 expression.Results: We identified 622 consecutive patients with mature T-cell and NK-cell lymphomas, including 317 (51.0%)patients with ENKTL. In addition, CD30 expression was detected in 43 (47.3%) of a subset of 91 patients with ENKTL.No clinicopathologic features were associated with CD30 expression, and CD30 positivity showed no prognosticsignificance in patients with ENKTL.Conclusions: ENKTL is the most common type of mature T-cell and NK-cell lymphoma diagnosed at our institution.CD30 is frequently expressed in ENKTL and represents a therapeutic target; however, it may not be a prognosticmarker.     

Natural killer-cell malignancies: diagnosis and treatment.

Natural killer (NK)-cell malignancies are uncommon diseases. Previously known as polymorphic reticulosis or angiocentric T-cell lymphomas, they are classified by the World Health Organization as NK/T-cell lymphoma, nasal type and aggressive NK-cell leukemia. They are prevalent in Asia and South America, but exceptionally rare in western countries. Pathologically, NK-cell lymphomas show a polymorphic neoplastic infiltrate with an angioinvasive and angiodestructive pattern. Lymphoma cells are characteristically CD2+, CD56+ and cytoplasmic CD3epsilon+. T-cell receptor gene is germline, and clonal Epstein-Barr virus (EBV) infection is almost invariably. Clinically, they can be divided into nasal, non-nasal, and aggressive lymphoma/leukemia subtypes. Most nasal NK-cell lymphomas present with stage I/II disease, and frontline radiotherapy is the most important key to successful treatment. Many stage I/II patients treated with radiotherapy fail systemically, implying that concomitant chemotherapy may be needed. Chemotherapy is indicated for advanced nasal NK-cell lymphoma, and the non-nasal and aggressive subtypes. However, treatment results are unsatisfactory. High-dose chemotherapy with hematopoietic stem cell transplantation may be beneficial to selected patients. The International Prognostic Index and presentation EBV DNA load is of prognostic significance and may be useful in the stratification of patients for various treatment modalities.     

Large granular lymphocyte leukemia

Clonal disorders of large granular lymphocytes (LGLs) represent a spectrum of biologically distinct lymphoproliferative diseases originating either from mature T cells (CD3+) or natural killer (NK) cells (CD3-). Both subtypes, T-cell and NK-cell LGL leukemia, can manifest as indolent or aggressive disorders. The majority of patients with T-cell LGL leukemia have a clinically indolent course with a median survival time >10 years. Immunosuppressive therapy with low-dose methotrexate, cyclophosphamide, or cyclosporine A can control symptoms and cytopenias in more than 50% of patients, but this approach is not curative. Several cases of an aggressive variant (CD3+ CD56+) of T-cell LGL leukemia with a poor prognosis have also been reported. Aggressive NK-cell LGL leukemia is usually a rapidly progressive disorder associated with Epstein-Barr virus (EBV), with a higher prevalence in Asia and South America. This disease is usually refractory to conventional chemotherapy, with a median survival time of 2 months. Chronic NK-cell leukemia/lymphocytosis is a rare EBV-negative disorder with an indolent clinical course. The malignant origin of this subtype is uncertain because clonality is difficult to determine in LGLs of NK-cell origin.     

Molecular analysis of tumor suppressor genes, Rb, p53, p16INK4A, p15INK4B and p14ARF in natural killer cell neoplasms.

Natural killer (NK) cell neoplasms, which are derived from mature or precursor NK cells, are rare diseases and are observed predominantly in Asian countries. We analyzed the status of the Rb, p53, p15INK4B, p16INK4A and p14ARF genes in these diseases by Southern blot, polymerase chain reaction-single strand conformational polymorphism (PCR-SSCP) and western blot analysis. We used 31 NK cell neoplasms, including four cell lines derived from NK cell neoplasms, 3 myeloid / NK cell precursor acute leukemias, 4 blastic NK cell lymphoma / leukemias, 4 aggressive NK cell leukemia / lymphomas, 4 nasal NK cell lymphomas, and 12 chronic NK lymphocytosis. We found gene amplification of the p53 gene in one nasal NK cell lymphoma, and point mutations of the p53 gene in one blastic NK cell lymphoma / leukemia and one chronic NK lymphocytosis. In addition, homozygous deletions of p15, p16 and p14 genes in 5 out of 31 samples were detected; 3 were from nasal NK cell lymphoma and 2 from blastic NK cell lymphoma / leukemia. Also hemizygous deletion of the Rb gene in one blastic NK cell lymphoma was detected. Rb proteins were highly expressed in one cell line as well as two myeloid / NK cell precursor acute leukemias. In other cell lines, complete loss and an aberrant migration pattern of Rb protein expression were observed. Comparative genomic hybridization suggested that the homozygous deletions of the p15, p16 and p14 were subtle chromosomal deletions and could not be identified by standard karyotyping in some cases. Although the number of cases we analyzed was not large, alterations identified in the Rb, p53, p16, p15 and p14 genes are of significance and might be associated with tumorigenesis in NK cell neoplasms.     

Molecular Analysis of Tumor Suppressor Genes, Rb, p53,pl6INK4A, pl5INK4B and p14ARF in Natural Killer Cell Neoplasms

Natural killer (NK) cell neoplasms, which are derived from mature or precursor NK cells, are rare diseases and are observed predominantly in Asian countries. We analyzed the status of the Rb, p53, p15INK4B, p16INK4A and p14ARF genes in these diseases by Southern blot, polymerase chain reaction–single strand conformational polymorphism (PCR–SSCP) and western blot analysis. We used 31 NK cell neoplasms, including four cell lines derived from NK cell neoplasms, 3 myeloid/ NK cell precursor acute leukemias, 4 blastic NK cell lymphoma/leukemias, 4 aggressive NK cell leukemia/lymphomas, 4 nasal NK cell lymphomas, and 12 chronic NK lymphocytosis. We found gene amplification of the p53 gene in one nasal NK cell lymphoma, and point mutations of the p53 gene in one blastic NK cell lymphoma/leukemia and one chronic NK lymphocytosis. In addition, homozygous deletions of pl5,p16 and p14 genes in 5 out of 31 samples were detected; 3 were from nasal NK cell lymphoma and 2 from blastic NK cell lymphoma/leukemia. Also hemizygous deletion of the Kb gene in one blastic NK cell lymphoma was detected. Rb proteins were highly expressed in one cell line as well as two myeloid/NK cell precursor acute leukemias. In other cell lines, complete loss and an aberrant migration pattern of Rb protein expression were observed. Comparative genomic hybridization suggested that the homozygous deletions of the p15, p16 and p14 were subtle chromosomal deletions and could not be identified by standard karyotyping in some cases. Although the number of cases we analyzed was not large, alterations identified in the Rb, p53, p16, p15 and p14 genes are of significance and might be associated with tumorigenesis in NK cell neoplasms     

Natural killer cell neoplasms

Lymphoid neoplasms that are derived from natural killer (NK) cells are uncommon but distinct clinicopathologic disease entities. Three types have been recognized and categorized in the latest World Health Organization classification: extranodal NK cell lymphoma, nasal-type; aggressive NK cell leukemia; and blastic NK cell lymphoma. All NK tumor cells express the NK cell marker CD56, but they lack the expression of surface CD3 and the rearrangement of T-cell receptor genes, which distinguish them from T-lymphoid neoplasms. There is also a strong association with the Epstein-Barr virus, except in blastic NK cell lymphoma. Extranodal involvement by the NK cell tumor is common, especially in the nasal cavity, the skin, and the gastrointestinal tract. All 3 NK cell neoplasms are characterized by aggressive clinical course and poor response to treatment. Although the optimal treatment modality remains to be determined, good initial response to combined radiation therapy and chemotherapy has been observed in localized disease. Further studies in the basic biology of the NK cell and the pathology of NK cell neoplasms may shed light on the development of newer and more effective therapy.     

Diseases of large granular lymphocytes.

BACKGROUND: Clonal diseases of large granular lymphocytes (LGLs) are rare lymphoproliferative malignancies that arise from either mature T-cell (CD3+) or natural killer (NK)-cell (CD3-) lineages. They manifest a distinct biologic behavior that ranges from indolent to very aggressive. METHODS: We discuss four distinct diseases involving LGLs: indolent T-cell LGL leukemia, aggressive T-cell LGL leukemia, chronic NK-cell leukemia, and aggressive NK-cell leukemia. Furthermore, we present an up-to-date systematic review of therapies for each entity. RESULTS: Sustained LGLs, characteristic immunophenotype, clonal origin of leukemic cells, and clinical presentation are the most important features that distinguish indolent from aggressive subtypes of LGL leukemia and guide the selection of therapy. Patients with symptomatic indolent T-cell or NK-cell LGL leukemia are usually treated with immunosuppressive therapies in contrast to aggressive T-cell and NK-cell LGL leukemia, which require intensive chemotherapy induction regimens. Novel targeted therapies using monoclonal antibodies against receptors, including CD2, CD52, the beta subunit of the interleukin-2 receptor, and small molecules such as tipifarnib, are undergoing evaluation in clinical trials. CONCLUSIONS: Future scientific advances focusing on the delineation of molecular pathogenic mechanisms and the development of new targeted therapies for each distinct LGL leukemia entity should lead to improved outcomes of patients with these disorders.     

NK/T Cell Lymphoma: Updates in Therapy

Purpose of Review

Extranodal NK/T cell lymphoma (ENKL), nasal type, is a highly aggressive lymphoma which used to show a poor clinical outcome. Expression of P-glycoprotein on lymphoma cells of ENKL is a major reason for the refractoriness to conventional chemotherapy containing anthracycline. However, recent innovative approaches have improved the outcome and prognosis of ENKL. The purpose of this review is to summarize the proceedings of treatment.

Recent Findings

Concurrent chemoradiotherapy containing platinum and several drugs including L-asparaginase, methotrexate, and alkylators shows excellent outcomes for the limited-stage ENKL. SMILE (steroid, methotrexate, ifosfamide, L-asparaginase, and etoposide) or other L-asparaginase-containing therapy is promising for advanced-stage ENKL, followed by either autologous or allogeneic hematopoietic stem cell transplantation. Anti-PD-1 or other immunological checkpoint inhibitors are recently reported to be effective for relapsed/refractory ENKL thought to be due to EBV-driven upregulation of PD-L1 expression.

Summary

The prognosis of ENKL is therefore improving by the introduction of these strategies. The 5-year overall survival (OS) rate of limited stage was 63.2% [95% confidence interval (CI), 55.3 to 70.0%] before 2010, but was 79.4% (95% CI, 66.9 to 87.6%) in 2010 or after. However, there still exists a room for improvement, particularly for advanced-stage patients. The 2-year OS of advanced ENKL was 30.3% (95% CI, 19.5 to 41.7%) before 2010, but was 40.5% (95% CI, 24.8 to 55.8%) in 2010 or after. Optimal treatment scheme should further be explored.

     

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.     

Cytotoxic activity of T- and NK-cell lymphoma cells is not dependent on a mature cytotoxic phenotype

Cytotoxic T- and NK-cell neoplasms constitute a rare clinico-pathological entity associated with aggressive clinical behaviour and a poor prognosis. The entity comprises a heterogenous group of different diseases classified by histologic, immunologic as well as clinical features. Recently, expression patterns of "cytotoxicity-associated proteins" such as T-cell intracellular antigen (TIA), perforin and granzyme B have been applied to differentiate between an immature (TIA positive) and a mature (TIA and perforin and/or granzyme B positive) phenotype of these malignant cells. In particular, expression of perforin and granzyme B are considered to mediate cytotoxic activity. This study assesses histology/cytology, immunophenotype, expression of "cytotoxicity-associated proteins" and the actual exhibition of cytotoxic activity of lymphoma cells of 10 patients suffering from different T- and NK-cell neoplasms. As investigated by PKH67 labelling of the target cells 6 out of 10 samples exhibited cytotoxic activity. Thus, all samples of lymphoma cells with a mature phenotype exhibited cytotoxic activity. Nevertheless, the ability to induce cytotoxic cell lysis was neither restricted to mature lymphoma cells, nor to lymphoma cells expressing "cytotoxicity-associated proteins": two samples with an immature phenotype and one CD4 positive sample, completely lacking expression of "cytotoxic proteins" as well as NK cell-associated markers, destroyed target cells. Artificial activation of a mature cytotoxic phenotype by cell culture conditions or contact of lymphoma cells with target cells was excluded by demonstrating the absence of perforin expression after the incubation period in two exemplary cases. In conclusion, we demonstrate that the exhibition of cytotoxic activity is neither restricted to cells with a mature phenotype, nor does it depend on the expression of the "cytotoxicity-associated proteins" TIA, perforin or granzyme B.     

L-Asparaginase-based treatment of 15 western patients with extranodal NK/T-cell lymphoma and leukemia and a review of the literature

Background: Extranodal natural killer (NK)/T-cell lymphoma,nasal type, and aggressive NK-cell leukemia are highly aggressivediseases with a poor outcome. Patients and methods: We report a multicentric French retrospectivestudy of 15 patients with relapsed, refractory, or disseminateddisease, treated with L-asparaginase-containing regimens inseven French centers. Thirteen patients were in relapse and/orrefractory and 10 patients were at stage IV. Results: All but two of the patients had an objective responseto L-asparaginase-based treatment. Seven patients reached completeremission and only two relapsed. Conclusion: These data, although retrospective, confirm theexcellent activity of L-asparaginase-containing regimens inrefractory extranodal NK/T-cell lymphoma and aggressive NK-cellleukemia. Therefore, L-asparaginase-based regimen should beconsidered as a salvage treatment, especially for patients withdisseminated disease. First-line L-asparaginase combinationtherapy for extranodal NK/T-cell lymphoma and aggressive NK-cellleukemia should be tested in prospective trials. Key words: L-asparaginase, NK/T-cell lymphoma Received for publication July 2, 2008. Accepted for publication July 4, 2008.