Natural killer lymphocyte blast crisis of chronic myelogenous leukemia

Blast phase of chronic myeloid leukemia presenting as early T-cell precursor acute lymphoblastic leukemia

OBJECTIVES

The blasts in most cases of chronic myeloid leukemia blast phase (CML-BP) have a myeloid or precursor-B immunophenotype, with only a small subset having T-cell or natural killer-cell lineage. Patients with CML-BP having early T-cell precursor acute lymphoblastic leukemia (ETP-ALL) are extremely rare.

METHODS

We report the clinicopathologic, immunophenotypic, and molecular genetic features and outcome of 3 patients with CML-BP who had ETP-ALL, with a review of the literature.

RESULTS

Only patient 1 had a history of chronic myeloid leukemia chronic phase. Fluorescence in situ hybridization revealed BCR::ABL1 rearrangement in cells with round nuclei (blasts) and cells with segmented nuclei (neutrophils) in cases 2 and 3, supporting a diagnosis of CML-BP rather than de novo Ph+ ETP-ALL. The blasts were positive for cytoplasmic CD3, CD7, CD33, and CD117; were negative for CD1a and CD8; and had dim CD5 expression in 2 cases. Next-generation sequencing showed a TET2 mutation in case 1 and BCOR, RUNX1, and STAG2 mutations in case 3. All patients received chemotherapy and tyrosine kinase inhibitors. Patients 2 and 3 died 33 days and 39 days, respectively, after diagnosis. Patient 1 received stem cell transplantation and was alive 14 months after blast phase.

CONCLUSIONS

Patients with CML-BP may have ETP-ALL. These patients usually have an aggressive clinical course, requiring intensive therapy, and may benefit from stem cell transplantation.

Immunophenotypic characterization of acute leukemias in Bahia, Brazil

OBJECTIVE

To characterize the immunophenotypic profile of acute leukemias in the population of the state of Bahia, Brazil.

METHODS

This is a descriptive, retrospective study. From 2014 to 2018, 796 new cases of acute leukemia were evaluated. The data were obtained from analysis of reports and records of tests performed by flow cytometry immunophenotyping. All individuals of all age groups diagnosed as acute lymphoblastic leukemia or acute myeloid leukemia were included in the study. Demographic variables and expression of leukemia antigens were evaluated.

RESULTS

Most cases were diagnosed as acute myeloid leukemia and 42.7% as acute lymphoblastic leukemia. Significant differences were found in expression of markers in acute leukemias when age groups were compared, as well as in demographic characteristics. B-cell acute lymphoblastic leukemia was more prevalent than cases of T-cell origin. Assessing the aberrant markers in acute myeloid leukemias, the non-acute promyelocytic leukemia group presented expression of CD7 and CD56 as the most frequent ones. In B-cell acute lymphoblastic leukemia, the most frequent aberrant markers were CD66c, CD13 and CD33.

CONCLUSION

Significant differences were found as to several antigens when comparing adults and children, and these findings may contribute to future studies correlating the phenotypic profile to genetic characteristics and therapeutic response, including specific antigen therapies, which may be better targeted.

Myeloid/natural killer cell blast crisis representing an additional translocation, t(3;7)(q26;q21) in Philadelphia-positive chronic myelogenous leukemia

We encountered a patient in blast crisis (BC) with chronic myelogenous leukemia (CML) who showed immunophenotypic features similar to those previously described in acute myeloid/natural killer (NK) cell precursor leukemia. The blasts were positive for CD7, CD33, CD34, and CD56. Cytogenetic analysis disclosed a Philadelphia chromosome (Ph) and t(3;7)(q26;q21). Molecular analysis did not detect any EVI1/CDK6 chimeric transcript generated by t(3;7)(q26;q21), but did indicate overexpression of EVI1, which occurs frequently in progression to myeloid BC in CML. Three cases of myeloid/NK cell precursor BC in CML have been reported, but this case is the first to present with Ph and EVI1 abnormality. These observations suggested that a myeloid/NK cell precursor might have been involved in the Ph-positive clone and have been a target for blastic transformation of CML, although EVI1 expression is not specific for transformation to BC from myeloid/NK lineage.

Expression of NK-associated antigens in extramedullary lymph nodal blast crisis of chronic myeloid leukemia on fine-needle cytology

A case is reported of a 62-yr-old male suffering from chronic myelogenous leukemia (CML) who developed an extramedullary, para-orthic lymph-nodal blast crisis without blood or bone marrow involvement and expression of CD56/NK associated marker. The diagnosis was performed on ultrasound-guided fine-needle cytology by an immunocytochemical and flow cytometric analysis. Conventional smears showed a monomorphous population of disperse, undifferentiated cells without cytoplasm. Cells showed fragile nuclei, vesicular chromatin, and evident nucleoli. Immunocytochemistry performed on cytospin slides were negative for cytokeratin, LCA, CD20, CD45Ro, and myeloperoxidase (MPO). Flow cytometry analysis proved the myeloid origin of the tumor by expression of CD13, CD34, and CD38 and showed aberrant expression of CD56. Cytological diagnosis was confirmed by histological examination. CD56 expression is generally an expression of NK lymphoid proliferation and may be observed in acute myelogenous leukemia but has rarely been reported in CML and its related blast crisis. This unusual expression, its possible explanation, the related technical problems, and clinicopathological aspects are discussed.

Immunophenotypic analysis of acute lymphocytic leukemia

Acute lymphoblastic leukemia (ALL) is one of the most common hematologic malignancies. Flow cytometry is an integral part of ALL diagnosis and also provides significant patient prognostic information. This article is a practical review of the basic principles of the flow cytometric evaluation of acute leukemias, the interpretation of flow cytometric data, and the management of practical problems such as aberrant antigen, hematogones, bone marrow regeneration, and minimal residual disease.

The BCR/ABL transgene causes abnormal NK cell differentiation and can be found in circulating NK cells of advanced phase chronic myelogenous leukemia patients

NK cells from the blood of chronic myelogenous leukemia (CML) patients are progressively decreased in number as the disease progresses from chronic phase to blast crisis. We hypothesize that BCR/ABL may be directly responsible by interfering with NK cell differentiation. CD34(+)HLA-DR(+) cells from CML patients were studied for their capacity to differentiate into NK cells. The NK cell cloning frequency was significantly decreased from CML CD34(+)HLA-DR(+) cells compared with cells from normal donors, yet CD34(+)HLA-DR(+) cells gave rise to BCR/ABL(+) NK cells in some patients. This finding prompted us to further investigate circulating NK cells from the blood of CML patients. CD56(+)CD3(-) NK cells were sorted from CML patients and examined by fluorescence in situ hybridization (FISH). In contrast to chronic phase CML, significant numbers of NK cells from advanced phase CML patients were BCR/ABL(+), whereas T cells were always BCR/ABL(-) regardless of the disease stage. To test the effects of BCR/ABL as the sole genetic abnormality, BCR/ABL was transduced into umbilical cord blood CD34(+) cells, and NK development was studied. p210-enhanced green fluorescence protein-transduced cells gave rise to significantly decreased numbers of NK cells compared with enhanced green fluorescence protein transduction alone. In addition, the extrinsic addition of BCR/ABL-transduced autologous CD34(+) cells suppressed the NK cell differentiation of normal umbilical cord blood CD34(+)CD38(-) cells. This study provides the first evidence that BCR/ABL is responsible for the altered differentiation of NK cells and that the NK cell lineage can be involved with the malignant clone in advanced stage CML.

Innovative therapy for chronic myelogenous leukemia

Innovative therapies for chronic myelogenous leukemia (CML) have focused mainly on combining autologous transplantation with another modality of therapy for purging of the graft or treatment of the patient after transplant. Of the three categories of innovative therapies, two are based on studies that demonstrate the bcr/abl gene rearrangement in the pathogenesis of CML, whereas the third is based on the observation that allogeneic disparity is important to maintain remissions in CML. The rationale and data supporting these innovative approaches are reviewed in this article and future strategies are discussed.

The role of autologous natural killer cells in chronic myelogenous leukemia

Chronic myelogenous leukemia (CML) is a lethal disease of the hematopoietic stem cell. Bone marrow transplantation has highlighted the importance of allogeneic disparity in maintaining remissions in CML. However, it has been unclear whether the immune effect against CML is mediated by T cells, natural killer cells (NK) or a combination of both. We have previously demonstrated that autologous activated NK are capable of selectively lysing malignant CML progenitors while sparing benign progenitors. NK effectors may play an important role in CML since NK lytic function, clonogenic frequency and proliferative capacity decrease as CML progresses from chronic phase to advanced phase and blast crisis. Incubation of CML NK with IL-2 is capable of restoring cytolytic activity to normal levels. We hypothesize that activated NK represent a potential therapy against CML to maintain remissions in a minimal residual disease setting induced by autologous transplantation. Clinical trials are in progress to test whether IL-2 based immunotherapy and activated cell infusions play a therapeutic role in CML.

Human NK cells in health and disease: clinical, functional, phenotypic and DNA genotypic characteristics

Natural killer (NK) cells are the subject of great current interest because of their possible (in vivo) role in tumour cell surveillance and killing, and because of the potential application of cytokine-modulated NK cells in cancer immunotherapy. In addition, clonal proliferations of NK-associated (NKa) cell populations represent a high proportion of chronic (non-B) lymphoid malignancies and abnormal (both clonal and non-clonal) NKa components are being increasingly reported in association with diverse clinical pictures such as autoimmune disease. This communication extensively reviews what is presently known regarding normal and leukaemic NKa phenotypic diversity, the mechanisms of NK-mediated cytolysis, the role of NK cells in malignancy, and the diagnostic and cellular aspects of malignant NKa proliferations.

CD56 (NKH1)-positive hematolymphoid malignancies: an aggressive neoplasm featuring frequent cutaneous/mucosal involvement, cytoplasmic azurophilic granules, and angiocentricity

CD56 (NKH1) expression is a rare phenomenon in malignant lymphomas, mostly confined to those occurring in the nasal or nasopharyngeal region. In this study we provide a detailed clinicopathologic analysis of nine patients with CD56-positive hematolymphoid malignancies occurring in sites other than the upper aerodigestive tract. The disease occurred predominantly in young and middle-aged men (mean age, 40 years) who often presented with swinging fever, skin rash, and/or hepatosplenomegaly, usually in the absence of peripheral lymphadenopathy. There was frequent involvement of the skin and mucosal sites, such as the salivary gland, lungs, and small intestine. The disease pursued a highly aggressive course, with most patients dying within weeks despite cytotoxic therapy. Although the cytologic appearances and immunophenotypic profile varied from case to case, the group of tumors could be unified by two morphologic features, namely, the presence of azurophilic granules in the cytoplasm of the neoplastic cells and the frequent occurrence of angiocentric and angiodestructive infiltrates. Since CD56 reactivity appears to confer a poor prognosis in hematolymphoid malignancies, we recommended inclusion of CD56 antibody in the routine panel for immunophenotypic analysis.

A study of lymphoma of large granular lymphocytes with modern modalities: report of two cases and review of the literature

Two cases of lymphoma of large granular lymphocytes are reported. The first case expressed natural killer (NK) cell, some T-cell (CD 2, CD 5, CD 8), and HLA-DR antigens, but was negative for other T-cell (CD 3, CD 4, CD 7), T-cell receptor (TCR), B-cell, and myeloid antigens. Germline configuration was demonstrated for TCR, and immunoglobulin heavy and light chain genes. The second case expressed NK cell, some T-cell (CD 3, CD 7, CD 8), and TCR antigens, but was negative for other T-cell (CD 4, CD 5), B-cell, myeloid, and HLA-DR antigens. Rearrangement of TCR alpha and beta chains were detected. Thus, the findings of case 1 were consistent with true NK cell lineage and case 2 with NK-like T-cell lineage. Our report underscores the heterogeneity of this newly recognized lymphoma, which nevertheless carries a consistently poor prognosis and is probably more prevalent in the Asian population. This study also provides information concerning immunophenotypes of cellular infiltrates in internal organs and cytogenetic abnormalities in this lymphoma; neither has been reported frequently in the literature. The importance of detecting cytoplasmic granules in tissue imprints or electron micrographs for differentiating other T-cell lymphomas is emphasized, and the classification of large granular lymphoproliferative disorders is discussed.