Haruko Tashiro

Molecular analysis of chronic eosinophilic leukemia with t(4;10) showing good response to imatinib mesylate

A 38-year-old Japanese man was referred to our hospital in June 2003 for treatment of acute respiratory failure with severe eosinophilia. Idiopathic hypereosinophilic syndrome had been diagnosed in 1994. However, karyotypic examination of bone marrow cells revealed that chromosomal translocation with t(4;10)(q12;p11) had occurred in 2000, and chronic eosinophilic leukemia was diagnosed. At admission, the patient’s respiratory condition was extremely serious, and mechanical support was necessary. Despite treatment with steroid pulse therapy and cytarabine, the blood eosinophil count did not decrease, and the patient’s respiratory condition worsened. After obtaining informed consent, we administered imatinib mesylate at a dose of 200 mg/day for 2 days and 100 mg/day for 3 days. The blood eosinophil count decreased dramatically over 5 days, and the patient’s condition rapidly improved, such that the patient could be discharged. In this case, we performed molecular analysis using peripheral blood. The FIP1-like 1 (FIP1L1)-platelet-derived growth factor receptor α (PDGFRα) fusion transcript was found with the reverse transcriptase polymerase chain reaction analysis. In this case, eosinophilia was possibly caused by constitutive activation of tyrosine kinase produced by the FIP1L1-PDGFRa fusion transcript.

FLT3 internal tandem duplication is associated with a high relapse rate and central nervous system involvement in acute promyelocytic leukemia cases: single institutional analysis

To the Editor: Internal tandem duplication of fms-like tyrosine kinase-3 (FLT3-ITD) is observed in 20–30% of the newly diagnosed acute myelogenous leukemia (AML) and indicates a significantly poorer prognosis in AML with normal karyotype (1). It has also been reported that a high prevalence of FLT3-ITD was observed in patients with AML who presented with central nervous system (CNS) involvement (2). In the all-trans retinoic acid era, acute promyelocytic leukemia (APL) has become the most curative subtype of AML (2); however, relapses still occur in 10–30% of patients after achieving the first complete remission (CR) (3). To improve prognosis further, risk-adapted therapy has also been utilized in APL (4). For APL, it remains under discussion whether FLT3ITD is a significant prognostic factor. Recently, it was reported that FLT3-ITD is associated with a high white blood cell (WBC) count at the onset and with poor overall and disease-free survival (5). However, there have not been any reports indicating whether FLT3-ITD is associated with CNS involvement among patients with APL. To clarify this issue, we retrospectively observed FLT3ITD and clinical outcomes of patients with APL. The institutional ethical committee approved this clinical observation, and we analyzed patients with APL who were hospitalized in our institute between November 1998 and December 2009. Patient characteristics are summarized in Table 1. Bone marrow cells were collected from informed patients, and the presence of FLT3-ITD was confirmed by the RT-PCR method (6). There were 26 patients who were screened for FLT3-ITD. Fifteen patients were men and 11 were women. FLT3-ITD was demonstrated on presentation in 6 (23%) (positive group). All patients were treated according to the Japan Adult Leukemia Study Group APL97 protocol (7). For remission induction therapy, patients received 45 mg ⁄m ⁄d of ATRA orally with or without idarubicin and cytarabine or idarubicin alone. After achieving CR, patients received three courses of consolidation chemotherapy. The first consolidation consisted of mitoxantrone on days 1–3 and Ara-C on days 1–5. The second consolidation contained Ara-C for 5 days, etoposide for 5 days, and daunorubicin on days 1 through 3. The third consolidation consisted of Ara-C for 5 days and idarubicin for 3 days. Methotrexate (15 mg), cytarabine (40 mg), and steroid were administered intrathecally for prophylaxis of CNS involvement to all patients after 1st or 2nd consolidation chemotherapy. CNS involvement was not revealed in any patients at their 1st lumabar puncture. All cases in both groups achieved CR. The relapse rates of FLT3-ITD-positive and FLT3-ITD-negative patients were 100% and 5%, respectively. Among positive patients, median duration from diagnosis to 1st relapse was 469 d (range 240–737). The rates of CNS involvement were 50% in the positive and 5% in the negative group. Among negative patients, only one patient had developed relapse. She presented with CNS relapse despite maintaining CR in the bone marrow. Thereafter, systemic relapse was demonstrated. Interest-

Colonic EBV-Associated Lymphoproliferative Disorder in a Patient Treated with Rabbit Antithymocyte Globulin for Aplastic Anemia

Epstein-Barr-virus- (EBV-) associated lymphoproliferative disorder (LPD) after immunosuppressive therapy for aplastic anemia (AA), in a nontransplant setting, has not been well described. We report one case of colonic EBV-LPD after a single course of immunosuppressive therapy for AA. The patient developed multiple colonic tumors 3 months after receiving immunosuppressive therapy, which consisted of rabbit antithymocyte globulin (ATG), cyclosporine, and methyl-predonisolone. The histological findings of biopsy specimens revealed that atypical lymphocytes had infiltrated colonic glands. Immunohistochemical staining for CD20 was positive, and in situ hybridization for EBV-encoded small RNAs was also positive. The EBV viral load in peripheral blood was slightly increased to 140/106 white blood cells. After the cessation of immunosuppressant, the colonic tumors spontaneously regressed, and the EBV viral load decreased to undetectable levels. This is the first report of the single use of rabbit ATG inducing colonic EBV-LPD. Because a single use of immunosuppressive therapy containing rabbit ATG can cause EBV-LPD, we should carefully observe patients receiving rabbit ATG for AA.

Vascular endothelial growth factor acted as autocrine growth factor in an acute promyelocytic leukemia case.

Vascular endothelial growth factor (VEGF) plays an important role in normal and neoplastic hematopoiesis [1,2]. In embryonic hematopoietic tissues, VEGF receptor type-1 (VEGFR-1) is expressed as a negative regulator, while VEGFR-2 plays an important role in embryonic and adult stable hematopoiesis; in the recovery phase following the suppression of hematopoiesis, VEGFR-1 acts to regulate hematopoiesis [2,3]. It is now known that, in some hematological malignancies, VEGF is expressed [2,4], and the autocrine VEGF stimulation of immature blasts has been reported [5]. In acute promyelocytic leukemia (M3), prominent production of VEGF has been reported, and angiogenesis is observed in bone marrow specimens [6]; however, VEGFRs are not expressed in M3 cells, and the VEGF-mediated activation of stromal cells induces leukemia cell proliferation in a paracrine fashion [7,8]. We encountered one case of M3 who relapsed soon after achieving complete remission (CR). We analyzed the molecular characteristics of M3 cells in this case, focusing on the VEGF system. A 43-year-old Japanese woman was admitted to our hospital in 2008 because of a bleeding tendency (petechiae in the skin, and gastrointestinal bleeding). The white blood cell count was 71,400/mL, in which myeloblasts comprised 41% and promyelocytes 9%. The blood hemoglobin level was 9.7 g/dL, and the platelet count was 75,000/mL. The bone marrow was hyperplastic (nuclear cell count of 480 000/mL), and promyelocytes had expanded to 97% with faggot cells, which were positive on CD13 and CD33 staining [Figure 1(C)]. Chromosomal analysis revealed 49,X,add(X)(q22),der(15)t(15;17)(q22;q12), –17,þmar16 3,þmar2, and fluorescence in situ hybridization analysis showed a 99% fusion signal for promyelocytic leukemia and retinoic acid receptor a. Disseminated intravascular coagulation and hyperfibrinolysis were demonstrated (prothrombin time international normalized ratio 2.35, activated partial thromboplastin time 33.1 s, fibrinogen 0.80 g/L, soluble fibrin monomers 156.8 mg/mL, plasma fibrinogen/fibrin degradation products 145.2 mg/mL, D dimer 61.5 mg/mL, thrombin–antithrombin complex 68.1 mg/L, plasmin–a2-plasmin inhibitor complex 23.9 mg/mL). We diagnosed the patient with M3, and all-trans retinoic acid was administered in combination with chemotherapeutic agents because of hyperleukocytosis. The patient achieved cytogenetic CR; however, during consolidation chemotherapy, M3 relapsed, and chemotherapy including arsenic trioxide was started. Bone marrow cells were collected after obtaining informed consent, mononuclear cells were prepared, and RNA was extracted, and this was used for reverse transcription-polymerase chain reaction (RT-PCR). Figure 1(A) shows the results, in which VEGF-A and VEGFR-1 and -2 were expressed in M3 cells in this patient, but not

Acute myelogenous leukemia cells with the MLL-ELL translocation convert morphologically and functionally into adherent myofibroblasts

Bone marrow-myofibroblasts, a major component of bone marrow-stroma, are reported to originate from hematopoietic stem cells. We show in this paper that non-adherent leukemia blasts can change into myofibroblasts. When myeloblasts from two cases of acute myelogenous leukemia with a fusion product comprising mixed lineage leukemia and RNA polymerase II elongation factor, were cultured long term, their morphology changed to that of myofibroblasts with similar molecular characteristics to the parental myeloblasts. The original leukemia blasts, when cultured on the leukemia blast-derived myofibroblasts, grew extensively. Leukemia blasts can create their own microenvironment for proliferation.

Chronic Myelogenous Leukemia Cells Contribute to the Stromal Myofibroblasts in Leukemic NOD/SCID Mouse In Vivo

We recently reported that chronic myelogenous leukemia (CML) cells converted into myofibroblasts to create a microenvironment for proliferation of CML cells in vitro. To analyze a biological contribution of CML-derived myofibroblasts in vivo, we observed the characters of leukemic nonobese diabetes/severe combined immunodeficiency (NOD/SCID) mouse. Bone marrow nonadherent mononuclear cells as well as human CD45-positive cells obtained from CML patients were injected to the irradiated NOD/SCID mice. When the chimeric BCR-ABL transcript was demonstrated in blood, human CML cells were detected in NOD/SCID murine bone marrow. And CML-derived myofibroblasts composed with the bone marrow-stroma, which produced significant amounts of human vascular endothelial growth factor A. When the parental CML cells were cultured with myofibroblasts separated from CML cell-engrafted NOD/SCID murine bone marrow, CML cells proliferated significantly. These observations indicate that CML cells make an adequate microenvironment for their own proliferation in vivo.

Vascular endothelial growth factor-C and its receptor type-3 expressed in acute lymphocytic leukemia cases with t(1;19)

The vascular endothelial growth factor (VEGF)-C system was analyzed in two cases of acute lymphocytic leukemia (ALL) with TCF3/PBX1 fusion to determine whether the VEGF-C system influences the growth of these ALL blasts. Bone marrow non-adherent mononuclear cells were prepared from the patients, and expressions of VEGFs and VEGF receptors (VEGFRs) were analyzed based on RNA and protein levels. Cell proliferation was also assayed with or without neutralizing antibodies to VEGFs. The patients’ leukemic blasts expressed a significant amount of VEGF-C and VEGFR type-3. When anti-VEGF-C antibody was added to the blast cell cultures, cell proliferation was suppressed. These observations indicate that, in our ALL cases with TCF3/PBX1 fusion, VEGF-C autocrine stimulation plays an important role in the proliferation of ALL.

Hyperuricemia in Hematologic Malignancies Is Caused by an Insufficient Urinary Excretion

In order to elucidate the mechanism of hyperuricemia in hematologic malignancies, we have retrospectively investigated the uric acid metabolism in 418 chemotherapy-naïve patients with hematologic malignancies. Hyperuricemia was present in 116 (27.8%) of these patients on initial hospitalization. Among 65 hyperuricemic patients analyzed uric acid metabolism, six (9.2%) had overproduction type, 52 (80.0%) had underexcretion type, and seven (10.8%) had a mixed type. Fourteen patients (3.3%) developed tumor lysis syndrome in 418 patients.

Chronic myelogenous leukemia cells convert to myofibroblasts in vitro: Effect of vascular endothelial growth factor on development of the microenvironment

To elucidate the biological characteristics of chronic myelogenous leukemia (CML) cells, we observed morphological and functional changes of CML cells during primary long-term culture, in which their morphology changed to that of myofibroblasts with similar molecular characteristics to the parental CML cells including BCR-ABL fusion gene, and produced cytokines such as granulocyte colony-stimulating factor, interleukin-6, and vascular endothelial growth factor (VEGF)-A. When cultured on the CML-derived myofibroblasts, parental non-adherent CML cells significantly proliferated. When anti-VEGF-A-neutralizing antibody was added to the cultures, non-adherent CML cell proliferation was significantly inhibited. These observations indicate that CML cells can convert their morphology and function to adherent myofibroblasts, and produce a significant amount of cytokine to give a growth-promotion activity to CML cells.

Autoimmune neutropenia due to antineutrophil antibodies in a patient with primary sclerosing cholangitis.

Autoimmune neutropenia (AIN) is defined as a decrease in the circulating absolute neutrophil count (ANC) to less than 1500/μl caused by serum antineutrophil antibodies. Secondary AIN is associated with various autoimmune diseases. Herein we present the case of a patient with primary sclerosing cholangitis (PSC) who developed secondary AIN. A 19-year-old man was admitted due to liver injury, and a diagnosis of PSC was established by cholangiogram and liver biopsy. Severe neutropenia, with the ANC down to 130/μl, developed during his hospital course. No medications had been given at that time and bone marrow aspiration revealed no abnormality. Therefore we suspected secondary AIN as a causative etiology and examined whether antineutrophil antibodies were detectable in the patient’s sera by flow cytometric analysis of the granulocyte indirect immunofluorescence test. We found that antineutrophil antibody was strongly positive on admission, and the titer decreased along with recovery from neutropenia. This is the first reported case of a patient with PSC who developed AIN, with detection of serum antineutrophil antibodies.