Megakaryocytic blast crisis as a first presentation of chronic myeloid leukemia

Reconstitution of NK cells expressing KIR3DL1 is associated with reduced NK cell activity and relapse of CML after allogeneic hematopoietic stem cell transplantation

Although the prognosis of chronic myeloid leukemia (CML) in blastic crisis remains poor, some patients achieve long-term remission after allogeneic hematopoietic stem cell transplantation (allo-HSCT). This may be attributable to graft-versus-leukemia (GVL) effects by donor lymphocytes, but their regulating mechanisms are unclear. Antitumor natural killer (NK) cell immunity is assumed to be important in CML, and we have previously shown that allelic polymorphisms of killer immunoglobulin-like receptors (KIRs) and histocompatibility leukocyte antigens (HLAs) are associated with the response of CML to tyrosine kinase inhibitors. Here, we report a case of CML in blastic phase who received HLA-matched but KIR3DL1 allelic-mismatched allo-HSCT. After transplant, decreased BCR-ABL transcript levels and enhanced NK cell activity were transiently observed. However, reconstitution of KIR3DL1-expressing NK cells occurred, which was associated with diminished NK cell activity and increased BCR-ABL. This case indicates the potential significance of KIR3DL1 in NK cell-mediated GVL activity following allo-HSCT. To the best of our knowledge, this is the first report to analyze the association between sequential KIR3DL1 expression and activity of NK cells after allo-HSCT. Selecting donors with KIR3DL1-null alleles may maintain competent GVL effects and provide improved outcomes in allo-HSCT for CML.

CML with Megakaryocytic Blast Crisis: Report of 3 Cases

Chronic myelogenous leukemia (CML) is a chronic myeloproliferative neoplasm consistently associated with the BCR-ABL1 fusion gene located in the Philadelphia chromosome. The Blast Phase is diagnosed when blasts are ≥20% of the peripheral blood white cell count or of bone marrow nucleated cells or when there is an extramedullary blast proliferation. Megakaryocytic blast crisis as the presenting manifestation of CML is extremely rare and only 7 reported cases were found in the literature. Out of 34 cases of CML-Blast Phase between April 2015 and June 2016, 3 cases showed megakaryocytic differentiation. 2 of these presented in Blast phase as the first manifestation of CML and the third case was a known case of CML-Chronic phase. Flow cytometric immunophenotyping was performed on peripheral blood/bone marrow using 6- color flow cytometer Navios. On CD45 vs SSC two distinct populations of blasts were seen in two cases and single population in the third case. All the 3 cases were positive for CD61, cCD41, cCD61 confirming the megakaryocytic lineage. The clinical features, morphologic and cytogenetic findings help in the identification and distinction of megakaryocytic blast phase of CML from Acute Megakayoblastic Leukemia. The diagnosis of such rare presentation of CML is essential for determining the choice of treatment. Therefore including a megakaryocytic marker in the primary flow cytometry panel is important so that these cases are not under-diagnosed as Acute myeloid leukemia because of expression of CD13 and CD33 only.

High abundance of circulating megakaryocytic cells in chronic myeloid leukemia in Indian patients. Revisiting George Minot to re-interpret megakaryocytic maturation

Circulating megakaryocytic cells abound in chronic myeloid leukemia (CML) seen in India and uniquely provide a setting for observing megakaryocytic maturation in the peripheral blood, a milieu not native to megakaryocytes. Peripheral blood megakaryocytic cells were studied in 324 cases of CML (235 chronic, 65 accelerated and 24 blastic phases). Two maturation themes were evident. Megakaryocytic blasts, especially in some cases of blast crisis, precociously make a foray into platelet formation and end up producing huge agranular or poorly granular cytoplasmic lobulated masses, that break off and come to lie in the circulation. This evidence of unsuccessful effort may exist, in a considerably attenuated form in chronic phase, alongside of the second major theme of megakaryocytic maturation centered around the familiar micromegakaryocyte, characteristic of the chronic phase. This cell is regarded as dysplastic, but produces morphologically normal platelets. The possibility that this occurs via a hitherto unstudied alternative path of platelet maturation that plays out in the peripheral blood, and the contrasting disorderly premature attempt of blasts to form platelets, represent exciting maturation processes that need further study. Our observations fortuitously constitute a revisit of the insightful exposition on the subject by George Minot nearly a century ago.

ARE/SUZ12 dual specifically-regulated adenoviral TK/GCV system for CML blast crisis cells

BACKGROUND

Treatment of blast phase chronic myeloid leukemia (BP-CML) remains a challenge, and the median survival is less than 6 months. Because effective treatments are lacking, we studied tight targeting of blast crisis CML cells using adenoviral (Ad) vectors expressing a HSV-TK system under dual control of a specific SUZ12 promoter and an antioxidant response element (ARE).

METHODS

A potential SUZ12 promoter fragment was designed with bioinformatics databases and identified with a luciferase assay. Next, we cloned the ARE element of the NQO1 gene and developed Ad vectors expressing TK kinase or luciferase under the dual control of a specific SUZ12 promoter and an ARE element. An in vitro transfection assay with Ad-ARE/SUZ12-Luc was used to determine promoter activity of ARE/SUZ12 regulatory element in blast crisis CML cells. After incubating human BP-CML-derived cells with Ad-ARE/SUZ12-TK and ganciclovir, Western blot, CCK8, Immunofluorescent assays and Annexin V assays were conducted to assess the efficacy of an ARE/SUZ12 dual-specific TK/GCV system for BP-CML cell lines.

RESULTS

Here, luciferase data confirmed significantly higher and specificer promoter activity of the ARE/SUZ12 composite component in CML blast crisis-derived cell lines (K562, KCL22, and K562/G01) compared to HepG2 cells, and Ad-AS-TK/GCV system could exhibit enhanced apoptotic effects and decreased cell viability for BP-CML cell lines. Additionally, Ad-AS-TK/GCV system altered expression of cycle-related and apoptosis-related proteins in BP-CML cell lines.

CONCLUSIONS

Thus, ARE/SUZ12 dual targeting TK/GCV system was effective in killing BP-CML cells. Moreover, efficacy and specificity of CML cell eradication were enhanced by synergistic effects of ARE/SUZ12 dual-specific regulation. We conclude that suicide gene-targeted therapy might hold promise for BP-CML treatment.

In vitro effects of imatinib on CD34+ cells of patients with chronic myeloid leukemia in the megakaryocytic crisis phase

Imatinib is a tailored drug for the treatment of chronic myeloid leukemia (CML), and has substantial activity and a favorable safety profile when used as a single agent in patients with CML in myeloid blast crisis. The megakaryocytic blast crisis in CML occurs rarely and carries a poor prognosis. The aim of the present study was to investigate the effects of imatinib on cluster of differentiation (CD)34⁺ cells from patients with CML in the megakaryocytic crisis phase. Bone marrow mononuclear cells (BMNCs) were isolated from patients with CML in the megakaryocytic crisis phase. CD34⁺ cells were selected from BMNCs by positive immunomagnetic column separation. Imatinib significantly induced G₁ arrest, reduced the phosphorylation of cyclin-dependent kinase 1 and retinoblastoma proteins and inhibited the proliferation of CD34⁺ cells from patients with CML in the megakaryocytic crisis phase. Annexin V/propidium iodide and caspase-3 activity showed that imatinib induced apoptosis. Western blot analysis and protein tyrosine kinase activity assays showed that imatinib inhibited BCR-ABL protein tyrosine kinase activity. The in vitro data thus markedly indicate a potential clinical application of imatinib for patients with CML in the megakaryocytic crisis phase.

A case of chronic myeloid leukaemia presenting as megakaryocytic blast crisis (AML M7)

Acute megakaryocytic leukaemia (AMeL) is a rare subtype of acute myeloid leukaemia, which can be frequently misdiagnosed as acute myelofibrosis or myelosclerosis [1]. Chronic myeloid leukaemia (CML) presenting primarily as megakaryocytic blast crisis is very rare, with very few case reports published to date [2, 3]. This case report describes a 36-year-old woman who presented with anaemia and massive splenomegaly with peripheral blood and bone marrow showing features of AMeL. Reverse transcriptase polymerase chain reaction and gel-electrophoretic study of peripheral blood leucocytes demonstrated breakpoint cluster region–Abelson oncogene translocation encoding for p210 fusion protein. Megakaryocytic blast crisis as the primary presentation of CML is very rare and requires clinical correlation and additional cytogenetic studies to determine the diagnosis.

Clinicopathological features of acute megakaryoblastic leukaemia: Relationship between fibrosis and platelet-derived growth factor

Acute megakaryoblastic leukaemia (AMGL) is an uncommon disease with poor prognosis. Histopathologically, AMGL cases show variable degree of fibrosis and the presence of uniform blasts or mature dysplastic megakaryocytes. Here we examined 18 cases of AMGL, including idiopathic (n = 9) and secondary (n = 9) cases. Fourteen cases were males and four were females, ranging in age from 14 to 87 years (median, 58). All cases had anaemia, but leukocyte and platelet counts varied. Blast cells were detected in the peripheral blood of 14 cases. Fourteen of 16 cases showed chromosomal abnormalities. The median survival was 6 months (range, 1-48 months). Survival rates did not correlate with the severity of fibrosis, proportion of blast cells and cause of AMGL. Nine of the 11 cases examined immunohistochemically were positive for platelet-derived growth factor (PDGF)(-BB), especially megakaryoblasts and a few fibroblasts. The PDGF-positive cases showed various degrees of fibrosis, while the negative cases showed no evidence of fibrosis. Our results confirmed the poor prognosis of patients with AMGL, irrespective of the degrees of fibrosis, and demonstrated that PDGF could play an important role in the pathogenesis of marrow fibrosis.

An unusual case of Philadelphia chromosome-positive chronic myelogenous leukemia with trisomy 19 presenting with megakaryoblastosis and myelofibrosis

Initial identification of chronic myelogenous leukemia is very important since targeted therapy leads to life-saving remission. Rarely, chronic myelogenous leukemia presents with an unusual picture, making the diagnosis challenging. We describe such a case of chronic myelogenous leukemia in blast crisis in a previously healthy 61-year-old woman. The patient presented with fever, myalgias, and night sweats and was first worked up for an infectious etiology. Because of persistent anemia, a bone marrow biopsy was performed that revealed fibrosis with increased megakaryoblasts. Even though initial cytogenetic studies could not be performed because of "dry tap" aspirate, persistent efforts for cytogenetic studies were made, including a "squeeze preparation" from the core biopsy, which revealed t(9;22)(q34;q11.2) and trisomy 19. The patient was treated with tyrosine kinase inhibitors, chemotherapy, and subsequently an allogeneic stem cell transplant. She is in persistent remission. This case illustrates a complex presentation of chronic myelogenous leukemia and provides an overview of morphologic cues and the importance of performing cytogenetic studies that led to the diagnosis.

De novo acute megakaryoblastic leukemia with p210 BCR/ABL and t(1;16) translocation but not t(9;22) Ph chromosome

Acute megakaryoblastic leukemia (AMKL) is a type of acute myeloid leukemia (AML), in which majority of the blasts are megakaryoblastic. De novo AMKL in adulthood is rare, and carries very poor prognosis. We here report a 45-year-old woman with de novo AMKL with BCR/ABL rearrangement and der(16)t(1;16)(q21;q23) translocation but negative for t(9;22) Ph chromosome. Upon induction chemotherapy consisting of homoharringtonine, cytarabine and daunorubicin, the patient achieved partial hematological remission. The patient was then switched to imatinib plus one cycle of CAG regimen (low-dose cytarabine and aclarubicin in combination with granulocyte colony-stimulating factor), and achieved complete remission (CR). The disease recurred after 40 days and the patient eventually died of infection. To the best of our knowledge, this is the first report of de novo AMKL with p210 BCR/ABL and der(16)t(1;16)(q21;q23) translocation but not t(9;22) Ph chromosome.

Severe Eosinophilia in an infant with congenital acute myeloid leukemia with t(3;4;6)(q26;q25;q21): a case report

We report a case of acute myeloid leukemia with morphologic features of M7 according to the FAB (French-American-British) classification and severe eosinophilia in the peripheral blood and bone marrow at diagnosis. We consider it as congenital leukemia, as the symptoms started in the first month of life of the affected child. This case of leukemia is characterized by t(3;4;6)(q26;q25;q21) cytogenetic abnormality. The blasts in flow cytometry analysis expressed markers of megakaryocytic lineage along with expression of myeloperoxidase in 30% of them. This type of acute myelogenous leukemia with severe eosinophilia can be considered as a distinct clinicopathologic entity.

Megakaryocytic blast crisis at presentation in a pediatric patient with chronic myeloid leukemia

Patients with chronic myeloid leukemia (CML) infrequently present in blast crisis (BC). While most BC are of myeloid origin, megakaryocytic BC is rare, especially at the time of CML diagnosis. We describe the first pediatric patient presenting with megakaryocytic leukemia and having BCR-ABL1 translocation as the single chromosomal abnormality. Clinical features were more suggestive of CML in megakaryocytic blast crisis than Philadelphia chromosome positive de novo AML. The patient was treated with AML-directed chemotherapy and imatinib mesylate followed by umbilical cord blood stem cell transplantation. The patient was in complete molecular response 16 months after stem cell transplantation.

Concurrent megakaryocytic and erythroid chronic myelogenous leukemia blast crisis

Chronic myelogenous leukemia with blast crisis is seen in 15% to 20% of patients with chronic myelogenous leukemia. Chronic myelogenous leukemia with either erythroid or megakaryocytic blast crisis is not uncommon in the clinical setting. The incidence ranges from 0% to 33% in accordance with literature reports. The diagnosis of erythroid or megakaryocytic blast phase is often challenging because the percentage of blasts in the blood or bone marrow required for diagnosis has not been firmly established. Also, some myeloblasts can have aberrant expression of either erythroid or megakaryocytic markers by flow cytometry during clonal evolution. Early recognition of this entity is crucial because either megakaryocytic or erythroid blast crisis predicts an aggressive clinical course. To our knowledge, the coexistence of megakaryocytic and erythroid blasts has not been reported. We report a unique case of chronic myelogenous leukemia with this rare bilineage blast crisis in the background of dysplasia and marked myelofibrosis. Related literature is also reviewed.

Megakaryocytic blast crisis as first presentation of chronic myeloid leukemia

We describe an extremely rare case of megakaryocytic blast crisis as first presentation of chronic myeloid leukemia. The patient had a very high platelet count and developed an ischemic stroke with seizures. She was treated with hydroxyurea, platelet apheresis, ARA-C, and idarubicin in order to obtain a prompt reduction of thrombocytosis and then with imatinib 600 mg/die PO. The therapy induced a complete hematological remission with a resolution of neurological signs within 4 weeks.

Co-existence of Philadelphia chromosome positive acute megakaryoblastic and B-lymphoblastic mixed blast crisis of chronic myeloid leukemia with chronic lymphocytic leukemia

In this study, we describe an extremely rare case of co-existence of a Philadelphia chromosome positive acute megakaryoblastic and B-lymphoblastic mixed blast crisis of chronic myeloid leukemia with chronic lymphocytic leukemia. A morphological, immunophenotypical and cytogenetic study has been performed to characterize the case and in order to identify the origin of two disorders. After the failure of the conventional therapy, the patient was treated with Imatinib with a complete hematological and cytogenetic response and a marked reduction of bone marrow fibrosis.