Esther Rosenthal

Effect of FXIII on monocyte and fibroblast function.

Factor XIII is a plasma transglutaminase that participates in the final stage of the coagulation cascade. Thrombin-activated FXIII (FXIIIa) catalyzes the formation of covalent crosslinks between γ-glutamyl and ε –lysyl residues on fibrin molecules to yield the mature clot. In addition to its role in hemostasis, FXIIIa was previously shown by us to stimulate endothelial cells to exhibit pro-angiogenic activity. In this work, we studied the effect of FXIIIa on other cells that participate in angiogenesis and tissue repair, such as monocytes and fibroblasts. FXIIIa significantly enhanced migration and proliferation, and inhibited apoptosis of monocytes and fibroblasts. Similar to our previous observations with endothelial cells, the stimulating effect of FXIIIa on monocytes and fibroblasts was elicited via its binding to α vβ 3 integrin leading to cJun upregulation and TSP-1 downregulation. Since monocytes and fibroblasts are essential components of the tissue repair process, the results of this study, together with the proangiogenic activity of FXIIIa, further substantiate a significant role of FXIII in tissue repair.

The SIL Gene Is Essential for Mitotic Entry and Survival of Cancer Cells

Although mitosis is a general physiologic process, cancer cells are unusually sensitive to mitotic inhibitors. Therefore, there is an interest in the identification of novel mitotic inhibitors. Here, we report the novel discovery of the SIL gene as a regulator of mitotic entry and cell survival. The SIL gene was cloned from leukemia-associated chromosomal translocation. It encodes a cytosolic protein with an unknown function and no homology to known proteins. Previously, we observed an increased expression of SIL in multiple cancers that correlated with the expression of mitotic spindle checkpoint genes and with increased metastatic potential. Here, we show that SIL is important for the transition from the G(2) to the M phases of the cell cycle. Inducible knockdown of SIL in cancer cells in vitro delayed entrance into mitosis, decreased activation of the CDK1 (CDC2)-cyclin B complex, and induced apoptosis in a p53-independent manner. SIL is also essential for the growth of tumor explants in mice. Thus, SIL is required for mitotic entry and cancer cell survival. Because increased expression of SIL has been noted in multiple types of cancers and correlates with metastatic spread, it may be a suitable target for novel anticancer therapy.

Central nervous system involvement at diagnosis in a case of pediatric CD30+ anaplastic large cell lymphoma

Central nervous system (CNS) involvement in Ki-1/CD30 lymphoma is extremely rare, in contrast to the frequent involvement in other types of pediatric non-Hodgkins lymphoma. No mechanism has yet been proposed to explain the sparing of the blood brain barrier in Ki-1/lymphoma. We present a 2-year-old boy who was admitted to the Department of Pediatric Hemato-Oncology due to lethargy, progressive breathing difficulties, massive diffuse lymphadenopathy, hepatosplenomegaly, and ichthyosis-like skin involvement with epidermolysis. A lymph node biopsy was compatible with Ki-1/CD30 anaplastic large cell lymphoma (ALCL). Bone marrow aspirate and biopsy demonstrated reactive hyperplasia. Cytogenetic analysis displayed hyperdiploid cells with 1p(-) in most cells. Cerebrospinal fluid examination showed pleocytosis with CD30+ cells. Possible mechanisms which could enable CNS involvement in this unusual case are discussed.

Acute lymphoblastic leukemia subtypes in israel: The sheba medical center experience☆

During the period from 1978 to 1981, 52 patients with ALL were diagnosed and treated at the Chaim Sheba Medical Center. Using standard cell markers to subtype the blasts, 49 of the patients could be classified: 16 were found to be T-cell ALL, 10 common ALL, five null ALL, four pre-B and 14 were partially characterized as non-B, non-T. Analysis of the series revealed two distinctive features: high prevalence (30%) of T-cell ALL among both Jews and Arabs and a high proportion, two-thirds, of high risk patients due to high initial WBC counts, unfavourable age or T-cell characteristics. The minimal incidence of ALL among the Gaza Strip Arab children during the study period is 4:100,000, which is close to the incidence in the Western world. During previous years the leukemia incidence in the Gaza Strip was very low while the most common lymphatic malignancies were Burkitt tumor and other non-Hodgkin lymphomas.

The Effect of Blockade of Tumor Necrosis Factor α on VLA-1+T-Cells in Rheumatoid Arthritis Patients

The α1β1 integrin, very late antigen (VLA)-1, characterizes collagen adherent interferon (IFN) γ producing memory T cells in inflamed synovium. We now report that the mean percentage of VLA-1+ T cells is significantly lower among peripheral blood mononuclear cells of rheumatoid patients responsive to antitumor necrosis factor (TNF) α therapy than of those with active disease not receiving therapy. Neutralization of TNFα during in vitro polyclonal activation of VLA-1− T cells reduced differentiation to expression of VLA-1 and inhibited secretion of IFNγ, but did not affect integrin expression on in vivo differentiated VLA-1+ T cells. Moreover, synovial fluids of patients relapsing during and after therapy were enriched in VLA-1+ T cells and lines derived from VLA-1+ T cells in peripheral blood of treated patients retained collagen binding and secreted IFN γ. Thus, whereas therapy decreases VLA-1+ T cells in rheumatoid arthritis patients, a subset is resistant and contributes to residual and recurring inflammation.

The distribution of B and T lymphocytes in the peripheral blood of patients with Hodgkin's disease.

The distribution of thymus-dependent (T cells) and bone marrow-derived lymphocytes (B cells) was studied in 74 patients with Hodgkins disease and 33 normal controls. A T cell deficit was found in untreated patients as well as in long-term survivors in remission. Therapy slightly enhanced the T cell depletion in Hodgkins disease patients. Concomitant with this finding was slight increase of B cells.

Proliferation Response of Leukemic Cells to CD70 Ligation Oscillates with Recurrent Remission and Relapse in a Low-Grade Lymphoma

Interactions of the TNF-related cell surface ligand CD70 with its receptor CD27 provide a costimulatory signal in B and T cell activation. Functional CD70-CD27 interactions could contribute to lymphoma and leukemia progression. This possibility was studied using DNA microarrays on a unique case of low-grade lymphoma/leukemia characterized by recurrent cycles of acute leukemic phase alternating with spontaneous remission. Upon induction of the acute phase expression of CD70 and CD27 in the leukemic cells increased 38- and 25-fold, respectively. Coexpression of membrane CD70 and CD27 on the leukemic (CD5+CD19+) cells was maximal 2–3 days following initiation of the attack. Soluble CD27 in the patient’s serum was elevated during remission and further increased in the attack. Functional tests showed that neither anti-CD70 nor anti-CD27 Abs affect the rate of apoptosis. However, the anti-CD70 Ab specifically enhanced proliferation of the remission phase leukemic cells, whereas proliferation of the acute-phase counterparts that express higher level of membrane CD70 was unaffected. Hence, in this lymphoma/leukemia, membrane CD70 is presented on the leukemic cells in a responsive state during the remission and a nonresponsive state during the attack. Presumably, CD70 in its responsive state provides a costimulatory receptor for initiating the next acute phase while its nonresponsive state enables the remission.

Neoplastic Cell Activation And Proliferative Response To CD40-Ligand Characterize Recurrent Leukemic Bouts In An Unusual Case Of Low Grade Lymphoma

Spontaneous fluctuations in activity of low-grade B cell lymphomas are common but not understood. An explanation may be offered by studying an atypical SLL/CLL case characterized by recurrent cycles of leukemic phase alternating with spontaneous remission (1). During remissions, residual IgMK+ leukemic cells exhibited resting phenotype, low proliferative response to CD40-ligand and delayed apoptosis. In contrast, the acute phase counterparts were phenotypically activated, underwent rapid apoptosis in culture and proliferated extensively in response to membrane-anchored CD40-ligand. Transient bursts of serum TNFa and IL-10 preceded the acute phases, which were characterized by the co-existence of CD40-ligand+ T lymphocytes and lymphoma cells in the bone marrow. Based on ex-vivo and in-vitro data, we suggest that changes in the lymphoma milieu affect the neoplastic cell activation status, rate of proliferation in response to activated T cells and rate of apoptosis. These responses may underlie both the induction and spontaneous regression of the acute phases in this unique lymphoma. Our findings raise the possibility that part of this mechanism may have evolved during transformation of indolent common CLL to its more aggressive form.

T-cell acute lymphoblastic leukemia in Israel: Clinical and laboratory features

T-cell acute lymphoblastic leukemia (ALL) comprises a third of the cases of childhood ALL in Israel. This high proportion of T-ALL is most probably due to a deficiency in pre-B/common ALL. The T-ALL patients had significantly worse 4-yr survival compared to standard risk or non-T high risk patients. In view of these special epidemiologic and clinical features a study of the immunophenotype of all consecutive cases of T-ALL and T-non Hodgkins lymphoma (NHL) observed in our medical center was performed. Twenty-eight ALL and 3 NHL patients were studied and their cells characterized using a panel of monoclonal antibodies, TdT reactivity and E-rosette formation. Assays of the activities of adenosine deaminase (ADA) and purine nucleoside phosphorylase (NP) were also performed. Based on the surface antigen expression, the tumor cells could be classified into one of the three known developmental stages of T cells. It was found that the immunophenotype of the T-ALL cases in Israel was similar to that observed in other countries. Considerable heterogeneity of surface antigen expression was found and in a number of cases the phenotype analysis was not easily reconciled with models of T-cell ontogeny. The activities of ADA and NP were correlated with the developmental stage, as defined by the surface antigenic expression. Contrary to observations on normal T-cells, where ADA activity decreases and NP activity increases as T-cells mature and differentiate, this was not found in the malignant T cells. These findings as well as the existence of atypical immunophenotypes suggest that the leukemic T cell has an abnormal gene expression.

Post-essential thrombocythemia myelofibrosis and chronic myelomonocytic leukemia can co-exist with complex cytogenetic abnormalities.

Cytogenetic abnormalities are detected in approximately 50% of atients with post-essential thrombocythemia myelofibrosis (postTMF) or post-polycythemia vera myelofibrosis (post-PVMF). ytogenetic abnormalities in these diseases are associated with sigificantly different survival outcomes. Isolated deletion 13q or 20q as favorable outcome similar to the presence of normal karyotype, hereas other cytogenetic abnormalities are unfavorable. [1–4]. lonal chromosomal evolution is frequently observed in post-PVMF nd less frequently in post-ETMF. Chronic myelomonocytic leukemia (CMML) is a rare disease. ccording to the new WHO classification, CMML is a myelodyslastic/myeloproliferative disorder (MDS/MPD) [5]. Furthermore, MML is divided into 2 prognostic categories, CMML-1 when ewer than 5% blasts are present in the peripheral blood (PB) nd less than 10% in the bone marrow (BM) or CMML-2 when % or more of blasts are present in the PB or 10% or more in the M. CMML can occur de novo, following chemotherapy or after mmunosuppressive drugs [6]. Here we present an unusual course of a patient who has postTMF and CMML for the last seven years. The clinical course of the ombined two hematological diseases, each one by itself being an ndication for stem cell transplantation, is presented along with the omplex cytogenetic abnormalities.