Showing papers in "International Journal of Hematology in 2003"

Survival and proliferation factors of normal and malignant plasma cells.

Abstract: Since the first identification of interleukin (IL)-6 as a myeloma cell growth factor by Dr. Kawano's and Dr. Klein's groups 14 years ago, numerous studies have emphasized its major roles in the emergence of malignant plasma cells in vivo and in the generation of normal plasma cells. Four transcription factors control B-cell differentiation into plasma cells. The B-cell transcription factor pax-5 is mainly responsible for a B-cell phenotype, and bcl-6 represses the plasma cell transcription factor blimp-1 and plasma cell differentiation. bcl-6 expression is triggered by CD40 and IL-4 activation. A lack of CD40 and IL-4 activation yields a down-regulation of bcl-6 expression, and IL-6 stimulation yields an up-regulation of blimp-1, mainly through STAT3 activation. Blimp-1 further down-regulates bcl-6 and pax-5 expression and makes plasma cell differentiation possible. IL-6 as well as IL-10 up-regulate XBP-1. XBP-1 is another transcription factor that is involved in plasma cell differentiation and whose gene expression is shut down by pax-5. The plasma cell transcription factors blimp-1 and XBP-1 are up-regulated, and the B-cell transcription factors bcl-6 and pax-5 are down-regulated, in malignant cells compared to B-cells. Apart from the recent identification of these 4 transcription factors, the factors involved in normal plasma cell generation are mostly unknown. Regarding malignant plasma cells, 3 categories of growth factors have been identified: (1) the IL-6 family cytokines, IL-10, and interferon alpha that activate the Janus kinase-signal transducer and activator of transcription (JAK/STAT) and mitogen-activated protein (MAP) kinase pathways; (2) growth factors activating the phosphatidylinositol (PI)-3 kinase/AKT and MAP kinase pathways, unlike the JAK/STAT pathway (insulin-like growth factor 1, hepatocyte growth factor, and members of the epidermal growth factor family able to bind syndecan-1 proteoglycan); and (3) B-cell-activating factor (BAFF) or proliferation-inducing ligand (APRIL) that activate the nuclear factor KB and PI-3 kinase/AKT pathways. BAFF and APRIL bind to BAFF receptor and TACI and are major B-cell survival factors. Recent data indicate that these various growth factors may cooperate to provide optimum signaling because they are localized together and with cytoplasmic transduction elements in caveolinlinked membrane caveolae. The identification of these myeloma cell growth factors and of the associated transduction pathways should provide novel therapeutic targets in multiple myeloma.

The Pathophysiology of Acute Graft-versus-Host Disease

Abstract: The pathophysiology of acute graft-versus-host disease (GVHD) is a complex process that can be conceptualized in three phases. In the first phase, high-dose chemoradiotherapy causes damage to host tissues, including a self-limited burst of inflammatory cytokines such as tumor necrosis factor (TNF)-α and interleukin 1. These cytokines activate host antigen-presenting cells (APCs). In the second phase, donor T-cells recognize alloantigens on host APCs. These activated T-cells then proliferate, differentiate into effector cells, and secrete cytokines, particularly interferon (IFN)-γ. In the third phase, target cells undergo apoptosis mediated by cellular effectors (eg, donor cytotoxic T-lymphocytes) and inflammatory cytokines such as TNF-α. TNF-α secretion is amplified by stimuli such as endotoxin that leaks across damaged gastrointestinal mucosa injured by the chemoradiotherapy in the first phase. TNF-α and IFN-γ cause further injury to gastrointestinal epithelium, causing more endo-toxin leakage and establishing a positive inflammatory feedback loop. These events are examined in detail in the following review.Int J Hematol. 2003;78:181-187. 2003 The Japanese Society of Hematology

Wilms tumor gene peptide-based immunotherapy for patients with overt leukemia from myelodysplastic syndrome (MDS) or MDS with myelofibrosis.

Abstract: The Wilms tumor gene, WT1, is overexpressed not only in leukemias and myelodysplastic syndrome (MDS) but also in various types of solid tumors, including lung and breast cancer, and the WT1 protein is a tumor antigen for these malignancies. In clinical trials of WT1 peptide-based cancer immunotherapy, patients with overt leukemia from MDS or MDS with myelofibrosis were injected intradermally with 0.3 mg of an HLA-A*2402-restricted, 9-mer WT1 peptide emulsified with Montanide ISA51 adjuvant. Only a single dose of WT1 vaccination resulted in an increase in WT1-specific cytotoxic T-lymphocytes, which was followed by a rapid reduction in leukemic blast cells. Severe leukopenia and local erythema at the injection sites of WT1 peptide were observed as adverse effects.These results have provided us with the first clinical evidence suggesting that WT1 peptide-based immunotherapy is an attractive treatment for patients with leukemias or MDS.

Pulmonary arterial hypertension in previously splenectomized patients with beta-thalassemic disorders.

Abstract: Our aim was to study the cause and describe the clinical features of pulmonary arterial hypertension (PHT) in splenectomized beta-thalassemia (beta-Thal) patients. Ten splenectomized beta-Thal patients with systolic pulmonary artery (PA) pressure >30 mm Hg were evaluated by echocardiography, right-heart catheterization, and pulmonary angiography. Five of these patients later underwent hemodynamic studies. Echocardiography and pulmonary angiography on the 10 patients showed normal values of left ventricular systolic function and no findings of acute or chronic pulmonary embolism. Hemodynamic evaluation showed very high PA pressures associated with markedly increased pulmonary vascular resistance indices (PVRIs). Hematological evaluation of the 10 patients showed marked anemia, markedly increased numbers of nucleated red blood cells (nRBCs), and serum ferritin. Mean platelet count, plasma beta2 thromboglobulin, and thrombin-antithrombin III complex levels were significantly increased. It was concluded that PHT can be found in splenectomized beta-Thal patients. Features associated with PHT were female sex, hemoglobin E/beta-Thal, status many years postsplenectomy, marked anemia, markedly increased nRBC count, thrombocytosis, and very high serum ferritin levels. PHT was not due to pulmonary emboli. Our findings suggested that severe PHT was due to increased PVRI from thrombotic pulmonary arteriopathy, likely from chronic low-grade hypercoagulability and platelet activation after splenectomy.

L-asparaginase-based regimen in the treatment of refractory midline nasal/nasal-type T/NK-cell lymphoma.

Abstract: Nasal, nasal-type T-cell/natural killer cell (T/NK-cell) lymphoma is a rare disease, and its prognosis is poor. Between March 1992 and March 2002 we investigated a new L-asparaginase-based salvage regimen to treat the disease and improve response to treatment and 5-year overall survival rate. Eighteen patients with refractory midline nasal, nasal-type T/NK-cell lymphoma, who were resistant to a cyclophosphamide, doxorubicin, vincristine, and prednisolone (CHOP)-like regimen, received an L-asparaginase—based salvage regimen (L-asparaginase, vincristine, and dexamethasone). Primary involved field radiation was given to the patients after chemotherapy.Ten (55.6%) of the patients achieved complete response (CR). Five patients (27.8%) achieved partial response (PR).The overall response rate (CR + PR) was 83.3%.The 5-year overall survival rate was 55.6%. Results of the preliminary clinical study indicated that the L-asparaginase—based salvage regimen significantly improved the response rate and 5-year survival rate.The findings suggested that the therapy is a promising new salvage regimen for treating refractory midline nasal, nasal-type T/NK-cell lymphoma. Int J Hematol. 2003;78:163-167.

Induction of umbilical cord blood mesenchymal stem cells into neuron-like cells in vitro.

Abstract: Mesenchymal stem cells (MSCs) in human umbilical cord blood are multipotent stem cells that differ from hematopoietic stem cells. They can differentiate in vitro into mesenchymal cells such as osteoblasts and adipocytes. However, differentiation into nonmesenchymal cells has not been demonstrated. Here, we report the isolation, purification, expansion, and differentiation of human umbilical cord blood MSCs into neurocytes in vitro. Cord blood samples were allowed to drain from the end of the cord into glass bottles with 20 U/mL preservative-free heparin. MSCs were isolated from human umbilical cord blood, purified, and expanded in Mesencult medium. Surface antigens of MSCs were analyzed by fluorescence-activated cell sorting (FACS). MSC passages 2,5, and 8 were induced to differentiate into neuron-like cells. Neurofilament (NF) and neuron-specific enolase (NSE) were detected by immunohistochemistry staining. Special Nissl bodies were observed by histochemical analysis. The results showed that 6.6 x 10(5) primary MSCs were expanded for 10 passages to obtain 9.9 x 10(8) MSCs, an increase of approximately 1.5 x 10(3)-fold. FACS results showed that the MSCs did not express antigens CD34, CD11a, and CD11b and expressed CD29 and CD71, an expression pattern identical to that of human bone marrow-derived MSCs. Induction results indicated that approximately 70% of the cells exhibited a typical neuron-like phenotype. Immunohistochemistry staining suggested that induced MSCs of different passages expressed NF and NSE. Special Nissl bodies were obvious in the neuron-like cells. These results suggest that MSCs in human umbilical cord blood are capable of differentiating into neuron-like cells in vitro.

Biology and clinical impact of human natural killer cells.

Abstract: Natural killer (NK) cells, through elaboration of cytokines and cytolytic activity, are critical to host defense against invading organisms and malignant transformation.Two subsets of human NK cells are identified according to surface CD56 expression. CD56dim cells compose the majority of NK cells and function as effectors of natural cytotoxicity and antibody-dependent cellular cytotoxicity, whereas CD56bright cells have immunomodulatory function through secretion of cytokines. For a long time, NK cells have held promise for cancer immunotherapy because, unlike T-lymphocytes, NK cells can lyse tumor cells without tumor-specific antigen recognition.To date, NK cell therapy, largely focused on in vivo expansion and activation with cytokines, has met with only modest success. However, recent understanding of the importance of NK receptors (NKR) for recognition and lysis of tumor cells while normal cells are spared suggests novel therapeutic strategies.The balance of inhibitory and activating signals through surface receptors that recognize major histocompatibility complex class I and class I-like molecules on target cells determines whether NK cells activate killing. Identification of NKR ligands and their level of expression on normal and neoplastic cells has important implications for the rational design of immunotherapy strategies for cancer.We review recent development in the biology and clinical relevance of NK cells in cancer immunotherapy.

Oxidative Stress and the Myelodysplastic Syndromes

Abstract: The evolution of higher organisms from anaerobic to aerobic living has promoted an elaborate mechanism of defense against potentially toxic oxidants. Many environmental toxicants implicated in the pathogenesis of myelodysplastic syndromes (MDS), including benzene and ionizing radiation, exert toxicity via pro-oxidant mechanisms. The emerging data suggest a probable genetic susceptibility to environmental carcinogenesis through functional polymorphic variants in enzymes that metabolize toxicants and/or protect against oxidative stress. The most studied enzyme is NAD(P)H:quinone oxidoreductase (NQO1). CD34+ cells from individuals homozygous for the NQO1 C609T nonfunctional allelic variant are incapable of enzyme induction following exposure to benzene, thus potentially increasing the hematotoxicity of benzene metabolites. Serologic and molecular markers of oxidative stress are present in many patients with MDS and include an increased concentration of the lipid peroxidation product malondialdehyde and the presence of oxidized bases in CD34+ cells. Potential mechanisms of oxidative stress include mitochondrial dysfunction via iron overload and mitochondrial DNA mutation, systemic inflammation, and bone marrow stromal defects. The biological activity of the antioxidant aminothiol amifostine in vivo suggests that these pathways may be meaningful targets for future therapy in MDS patients.

Deoxycoformycin-Containing Combination Chemotherapy for Adult T-Cell Leukemia-Lymphoma: Japan Clinical Oncology Group Study (JCOG9109)

Abstract: Aggressive adult T-cell leukemia-lymphoma (ATL) generally has a very poor prognosis. Deoxycoformycin (DCF, pentostatin), an inhibitor of adenosine deaminase, has shown promising therapeutic efficacy for ATL. To develop a new effective therapy against aggressive ATI., we carried out a multicenter phase II study of DCF-containing combination chemotherapy. Sixty-two previously untreated patients with ATL (34, 21, and 7 patients with diseases of the acute, lymphoma, and unfavorable chronic types, respectively) were enrolled, but 2 were ineligible because they were judged to be favorable chronic types. A regimen of 1 mg/m2 vincristine intravenously on days 1 and 8, 40 mg/m2 doxorubicin intravenously on day 1,100 mg/m2 etoposide intravenously on days 1 through 3, 40 mg/m2 prednisolone orally on days 1 and 2, and 5 mg/m2 DCF intravenously on days 8,15, and 22 was administered every 28 days for 10 cycles unless disease progression or toxic complications occurred. Fifty-two percent of 60 eligible patients responded (95% confidence interval [CI], 38%-65%), with 17 patients (28%) achieving a complete response (CR) (95% CI, 17%-41%) and 14 achieving a partial response. The CR rate was inferior to those of both the previous Japan Clinical Oncology Group (JCOG) study (JCOG8701, 43%), a 9-drug combination chemotherapy of the second generation, and the subsequent JCOG9303 study (35%), a granulocyte colony-stimulating factor-supported, dose-intensified, 9-drug regimen. The median survival time of the 60 eligible patients in JCOG9109 was 7.4 months, and the estimated 2-year survival rate was 15.5%; these results were identical with those of JCOG8701 but inferior to those of JCOG9303. Grade 4 neutropenia and infection of grade 3 or greater were frequent (67% and 22%, respectively), and treatment-related death was observed in 4 patients (7%), scpticcmia in 2, and cytomcgalovirus pneumonia in 2. We conclude that DCF-containing combination chemotherapy is not a promising regimen against aggressive ATL.

Platelet recovery in patients with idiopathic thrombocytopenic purpura after eradication of Helicobacter pylori.

Abstract: The relationship betweenHelicobacter pylori infection and idiopathic thrombocytopenic purpura (ITP) has been investi-gated in several studies. We investigated the prevalence ofHpylori infection and the clinical effects of eradication in 22 Japan-ese patients with chronic ITP.H pylori infection was found in 14 (63.6%) of the patients by histologie and culture examina-tions of biopsy samples obtained by gastrointestinal endoscopy.Hpylori was eradicated by proton pump inhibitors and 2 kinds of antibiotics in 13 (92.9%) of the 14 patients in whom the results of treatment could be evaluated. Five (38.4%) of those 13 patients had platelet recovery (platelet count of more than 100 X 107L and an increase of more than 30 X 109/L with respect to the baseline value) after eradication. Hie median follow-up period was 15 months. One patient who had a complete response had a partial relapse after cessation of prednisolone treatment without any evidence ofH pylori reinfection. Another patient, in whomH pylori was not eradicated even after 2 treatment sessions, had a partial response after treatment. A screening exam-ination forH pylori infection may be necessary for Japanese patients with newly diagnosed ITP. Although the exact mechanism underlying platelet recovery afterH pylori eradication is not clear, the results of this study indicated thatH pylori eradication treatment is a good option for some patients with chronic ITP.

Can Eradication Therapy for Helicobacter pylori Really Improve the Thrombocytopenia in Idiopathic Thrombocytopenic Purpura? Our Experience and a Literature Review

Abstract: Helicobacter pylori has recently been postulated to play a role in the pathogenesis of autoimmune diseases, including idiopathic thrombocytopenic purpura (ITP). We investigated the prevalence ofH pylori infection and the effects of its eradication in 61 patients with ITP.H pylori infection was found in 50 patients (83%), an incidence significantly higher than not only healthy volunteers in Japan (60%) but also subjects in other reported ITP series (approximately 43%–71%). In our study, the mean age ofH pylori-positive ITP patients (58.0 years) was significantly higher than that ofH pylori-negative ITP patients (40.5 years). Bacterium eradication efforts were performed in 29 infected ITP patients and succeeded in 27 patients (93%). The 29 patients with eradicatedH pylori infections showed significant increases in platelet counts compared with patients with uneradicated infections or who wereH pylori-negative. During the follow-up period (median, 11.0 months), 16 (55%) of 29 patients achieved a major or a minor response. The patients who achieved a major response had not received previous prednisolone therapy, suggesting a relationship between prednisolone therapy and the response to eradication efforts.The assessment ofH pylori infection and its eradication should be attempted in cases of ITP, because this approach may be a good new strategy for treating some ITP patients, especially elderly Japanese patients. Some regional factors have been suggested as causes ofH pylori-associated ITP.

The bisphosphonate zoledronic acid induces cytotoxicity in human myeloma cell lines with enhancing effects of dexamethasone and thalidomide.

Abstract: Bisphosphonates have recently been introduced in the therapeutic armamentarium for long-term treatment of patients with multiple myeloma. These pyrophosphate analogs not only reduce the occurrence of skeletal events but also provide clinical benefit to patients and improve the survival of some of them. The existence of these capabilities raises the possibility that these compounds may have a direct antiproliferative effect on tumor cells. To investigate whether these drugs exert a direct antitumor effect, we exposed human myeloma cell lines ARH-77 and RPMI-8226 to increasing concentrations of zoledronic acid (ZOL) in vitro. A concentration- but not time-dependent cytotoxic effect was detected with drug treatment of ARH-77 and RPMI-8226 cell lines (30% and 60% at 48 hours and 38% and 62% at 72 hours, respectively, for 50µM of ZOL). Cytotoxicity was not due to ZOL-induced chelation of extracellular calcium as shown by control experiments with the calcium chelator ethylene glycol-bis(β-aminoethylether)-N,N,N’,N’-tetraacetic acid. Addition of the competitive inhibitor of the nitric oxide synthase Nω-nitro-L-arginine methyl ester did not modulate ZOL-induced cytotoxicity. However, a decrease in the number of apoptotic cells was detected when protein kinase C was inhibited by addition of staurosporine to ZOL-containing cultures. Cytotoxicity also was increased by addition of dexamethasone (Dex) and thalidomide (Thal) to ARH-77 and RPMI-8226 cultures. We demonstrated that exposing myeloma cell lines ARH-77 and RPMI-8226 to ZOL inhibits cell growth in a dose-dependent but not a time-dependent manner and that combination of Dex and Thal with ZOL induces apoptotic cell death, providing a rationale for potential applications in vivo.

T-cell control by human T-cell leukemia/lymphoma virus type 1.

Abstract: Human T-cell leukemia/lymphoma virus type 1 (HTLV-1) causes neoplastic transformation of human T-cells in a small number of infected individuals several years from infection. Collective evidence from in vitro studies indicates that several viral proteins act in concert to increase the responsiveness of T-cells to extracellular stimulation, modulate proapoptotic and antiapoptotic gene signals, enhance T-cell survival, and avoid immune recognition of the infected T-cells. The virus promotes T-cell proliferation by usurping several signaling pathways central to immune T-cell function, such as antigen stimulation and receptor-ligand interaction, suggesting that extracellular signals are important for HTLV-1 oncogenesis. Environmental factors such as chronic antigen stimulation may therefore be of importance, as also suggested by epidemiological data. Thus genetic and environmental factors together with the virus contribute to disease development. This review focuses on current knowledge of the mechanisms regulating HTLV-1 replication and the T-cell pathways that are usurped by viral proteins to induce and maintain clonal proliferation of infected T-cells. The relevance of these laboratory findings is related to clonal T-cell proliferation and adult T-cell leukemia/lymphoma development in vivo.

In vivo Platelet Activation and Hyperaggregation in Hemoglobin E/β-Thalassemia: A Consequence of Splenectomy

Abstract: Patients with hemoglobin E/β-thalassemia (E/β-Thal) who have undergone splenectomy are prone to thrombosis in the small pulmonary arteries.To study the role of platelets in this situation, we assayed plasma β2-thromboglobulin (βTG) and performed whole blood platelet aggregation analysis of 30 E/β-Thal patients, half of whom had undergone splenectomy.We compared results with those obtained with 15 healthy control subjects. Plasma βTG levels in splenectomy patients were significantly higher than in control subjects and patients who had not undergone splenectomy, and platelets in splenectomy patients exhibited hyperaggregation in response to adenosine diphosphate, thrombin, and ristocetin. Levels of plasma thrombin-antithrombin III complex were also significantly higher. This finding is likely due to an increased number of erythrocytes with exposed phosphatidylserines, an effect that has been associated with splenectomy. The increased presence of thrombin in the blood may well be the cause of platelet hyperactivity, which was evident only in the asplenic patients. Platelet hyperactivity very likely plays a pathogenetic role in the thrombosis of small pulmonary arteries that occurs in E/β-Thal patients who have undergone splenectomy.

Leukemia and lymphoma of natural killer lineage cells.

Abstract: Natural killer (NK) cells are lymphocytes with a large granular lymphocyte morphology, a CD3-CD56+ phenotype, a nonmajor histocompatibility complex-restricted cytotoxicity, and germline configuration T-cell receptor genes. NK cell lineage tumors originate from either precursor NK cells or mature NK cells.Tumors originating conceivably from precursor NK cells include myeloid/NK cell precursor acute leukemia, precursor NK cell acute lymphoblastic leukemia, and blastic NK cell lymphoma. However, because the developmental pathway of normal NK cells and the characteristics of these NK precursors are not fully understood, the definition and characterization of the tumors are only provisional.Tumors of mature NK cell origin include aggressive NK cell leukemia/lymphoma, nasal-type NK cell lymphoma, and chronic NK lymphocytosis, but the last disorder seems to be reactive in most cases. Because NK cell tumors are rare and difficult to manage, vigorous studies are required for their understanding and management.

Racial background is a determinant factor in the maintenance dosage of warfarin.

Abstract: Warfarin is a drug commonly used in the prevention of thromboembolic events. There have been reports suggesting that racial background may influence warfarin dose requirements. Malaysia is a multiracial country in which there are 3 major races, Malay, Chinese, and Indian.We examined 100 patients from our hospital on stable maintenance doses of warfarin, with international normalized ratio (INR) of 2.0 to 3.5.We found that the mean warfarin dose for Indian patients (n = 19) was 6.9 mg, for Chinese patients (n = 55) was 3.6 mg, and for Malay patients (n = 26) was 3.2 mg.The results showed that the Indian patients required a statistically significantly higher warfarin dose than did patients of the other 2 races (P >.0005). Age was also found to affect the daily warfarin maintenance dose.

Antiapoptotic effect of granulocyte colony-stimulating factor, granulocyte-macrophage colony-stimulating factor, and cyclic AMP on human neutrophils: protein synthesis-dependent and protein synthesis-independent mechanisms and the role of the Janus kinase-STAT pathway.

Abstract: Spontaneous neutrophil apoptosis during culture was delayed by granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage CSF (GM-CSF), or dibutyryl-cyclic adenosine monophosphate (cAMP), whereas apoptosis was accelerated by cycloheximide or actinomycin D. G-CSF-mediated antiapoptosis was completely abolished by cycloheximide or actinomycin D, whereas GM-CSF-mediated antiapoptosis was not completely abolished by these inhibitors. Antiapoptosis induced by dibutyryl-cAMP was highly resistant to cycloheximide, and that induced by benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone was unaffected by cycloheximide. G-CSF- and GM-CSF-mediated antiapoptosis and phosphorylation of signal transducer and activator of transcription 3 (STAT3) and STAT5 were inhibited by AG490, an inhibitor of Janus kinase.The level of Mcl-1 protein was not associated with neutrophil apoptosis. The results suggest that (a) neutrophil survival in the resting state is primarily regulated by the constitutive synthesis of antiapoptotic proteins; (b) the prevention of spontaneous apoptosis is mediated through the protein synthesis-dependent and/or protein synthesis-independent mechanisms according to the stimuli used; and (c) the Janus kinase-STAT pathway is involved in G-CSF- and GM-CSF-mediated antiapoptosis.

International collaboration on childhood leukemia.

Abstract: The current cure rate of childhood acute lymphoblastic leukemia has reached 80% in many industrialized countries, but in developing countries the rate is often less than 10%.To advance the cure rate, investigators have formed several parallel initiatives in both industrialized and developing countries through international collaboration and partnership. Among industrialized countries, investigators have combined data to conduct in-depth studies of the biology and heterogeneity of high-risk or drug-resistant subgroups of leukemia to identify optimal or novel treatments. Alliances have been established among government, local nongovernmental organizations, health care providers, and international groups to improve the survival rate of childhood leukemia in developing countries. “Twinning” partnerships between a well-established individual institution or study group and a pediatric cancer unit in a developing country has proved to be the most successful strategy to date.

Diagnosis and treatment of Epstein-Barr virus-associated natural killer cell lymphoproliferative disease.

Abstract: Epstein-Barr virus (EBV) exhibits tropism for both lymphocytes and epithelial cells and can induce both replicative (productive/ lytic) and latent (persistent) infections that result in a variety of human diseases.With regard to lymphocytes, latent EBV infection is linked to development of heterogeneous lymphoproliferative disease (LPD), such as B-cell LPD and T-cell/ natural killer cell (T/NK cell) LPD. Unlike B-cell LPD, LPD derived from T-cells and NK cells sometimes has overlapping clinical symptoms, as well as histologic and immunophenotypic features, because both types of cells are derived from a common precursor. However, determination of cell lineage is important in classification of lymphoid neoplasms, and combined modern techniques allows us to distinguish NK cell LPD from T-cell LPD in most instances. Because NK cell LPD seems to be heterogeneous in terms of clinical features, prognosis, and diagnosis and has a monoclonal or polyclonal (or oligoclonal) nature, this review attempts to clarify recent research and clinical findings and to establish diagnostic and therapeutic strategies.

L-asparaginase-Based induction therapy for advanced extranodal NK/T-cell lymphoma.

Abstract: We describe treatment of a patient with advanced extranodal NK/T-cell lymphoma, nasal type, with multiple subcutaneous lesions and hemophagocytic syndrome. Considering the projected poor outcome of conventional treatments, we designed an L-asparaginase-based induction therapy. L-asparaginase (4000 units/day, day 1 to day 7) combined with vincristine (1 mg, day 1) and prednisolone (100 mg/day, day 1 to day 5) was administered by intravenous infusion every 3 weeks. Within a week after treatment was started, excellent response was observed. Because of an allergic reaction to L-asparaginase, 6 courses of CHOP (adriamycin, cyclophosphamide, vincristine and prednisolone) therapy were administered as consolidation after 4 courses of L-asparaginase. The lymphoma was controlled with complete remission lasting longer than 2 years without additional treatment. These results and related reports may contribute to greater therapeutic efficacy against at least some cases of extranodal NK/T-cell lymphoma and other related diseases. Further evaluations based on clinical study are expected to clarify these results.

Hemophagocytic syndrome: an unusual manifestation of acute human immunodeficiency virus infection.

Abstract: An 18 year-old heterosexual man was hospitalized because of fever, chills, a sore throat, and a dry cough for 8 days. He had had sexual intercourse with a new partner within the 4 months prior to admission. At admission, the patient presented a clinical picture compatible with hemophagocytic syndrome (HPS). The presence of hemophagocytosis was subsequently determined pathologically from bone marrow and lymph node specimens. An exhaustive diagnostic work-up failed to reveal any causative etiology, the symptoms improving after 2 doses of intravenous immunoglobulin (IVIG) infusion, given at a dose of 0.5 mg/kg each, the 2 doses being administered 1 week apart. Three months subsequent to the patient's initial presentation, acute human immunodeficiency virus (HIV) infection was diagnosed, and the patient received highly active antiretrovirus therapy (HAART) from the time of diagnosis. The patient remained well for the following 2 years. HPS in the advanced stages of HIV infection has previously been described, but HPS during seroconversion of an acute form of the infection is rare. We most definitely suggest, however, that acute HIV infection be included in the list of potential causes of HPS. IVIG therapy appears to be an appropriate therapeutic modality, and HAART also is effective, for prevention of recurrence of HPS in a patient with acute HIV infection.

Molecular genetics of paroxysmal nocturnal hemoglobinuria.

Abstract: Paroxysmal nocturnal hemoglobinuria (PNH) is an acquired hematopoietic stem cell disorder characterized by the clonal expansion of glycosylphosphatidylinositol (GPI)-deficient cells that leads to complement-mediated hemolysis. A somatic mutation in thePIG-A gene involved in GPI biosynthesis causes a deficiency of GPI-anchored proteins. However, it is evident that the clonal expansion of GPI-deficient cells is not caused by only thePIG-A mutation and that other changes should be involved in the development of PNH. Some patients with aplastic anemia (AA) develop PNH. Furthermore, it has been reported that most patients with AA and refractory anemia (RA) who carry HLA-DRB1*15 and show a good response to immunosuppressive therapies have an expanded population of GPI-deficient clones. This finding, together with recent data showing resistance of GPI-deficient cells to cytotoxic cells, suggests that GPI-deficient cells escape immunologic attack and are positively selected in the autoimmune environment. However, GPI-deficient clones found in AA and RA are generally small and do not increase to near-complete dominance. Therefore, 1 or more additional genetic abnormalities that confer the growth phenotype on GPI-deficient cells are probably required for fully developed PNH or so-called florid PNH. The next 10 years should witness the discovery of the molecular mechanisms of immunologic selection and the identification of abnormalities involved in the further clonal expansion of PNH cells.

Clinical manifestations of paroxysmal nocturnal hemoglobinuria: present state and future problems.

Abstract: The clinical pathology of paroxysmal nocturnal hemoglobinuria (PNH) involves 3 complications: hemolytic anemia, thrombosis, and hematopoietic deficiency. The first 2 are clearly the result of the cellular defect in PNH, the lack of proteins anchored to the membrane by the glycosylphosphatidylinositol anchor. The hemolytic anemia results in syndromes primarily related to the fact that the hemolysis is extracellular. Thrombosis is most significant in veins within the abdomen, although a number of other thrombotic syndromes have been described. The hematopoietic deficiency may be the same as that in aplastic anemia, a closely related disorder, and may not be due to the primary biochemical defect. The relationship to aplastic anemia suggests a nomenclature that emphasizes the predominant clinical manifestations in a patient. This relationship does not explain cases that appear to be related to myelodysplastic syndromes or the transition of some cases of PNH to leukemia. Treatment, except for bone marrow transplantation, remains noncurative and in need of improvement.

The role of the MLL gene in infant leukemia.

Abstract: TheMLL gene is a major player in leukemia, particularly in infant leukemia and in secondary, therapy-related acute leukemia. The normalMLL gene plays a key role in developmental regulation of gene expression (includingHOX genes), and in leukemia this function is subverted by breakage, recombination, and chimeric fusion with one of 40 or more alternative partner genes. In infant leukemias, the chromosome translocations involvingMLL arise during fetal hematopoiesis, possibly in a primitive lymphomyeloid stem cell. In general, these leukemias have a very poor prognosis. The malignancy of these leukemias is all the more dramatic considering their very short preclinical natural history or latency. These data raise fundamental issues of how such divergentMLL chimeric genes transform cells, why they so rapidly evolve to a malignant status, and what alternative or novel therapeutic strategies might be considered. We review here progress in tackling these questions.

Generation of CD3+CD56+ cytokine-induced killer cells and their in vitro cytotoxicity against pediatric cancer cells

Abstract: A certain number of pediatrie cancer patients still succumb to relapse following conventional treatment of their malignancies. One of the mechanisms of relapse is escape from immunity. Adoptive cellular immunotherapy with effector cells has the potential to overcome this escape. In adults, the CD3+CD56+ cell, a cytokine-induced killer (CIK) cell, appears to be a promising effector cell type with the greatest cytotoxicity. This effector cell type may work in children as well. No similar studies with children have been published. We speculated that expanded CD3+CD56* cells obtained from pediatrie cancer patients during remission would act similarly against various pediatrie tumor cell lines; therefore, we undertook the present study to find support for our speculation. This study was undertaken to generate and expand CD3’CD56’ CIK cells from normal peripheral blood mononuclear cells (PBL) obtained from 6 children with cancer (2 with acute lymphoblastic leukemia, 2 with large cell lymphoma, and 2 with osteosarcoma) in remission after intensive chemotherapy and to study the cytotoxic activities of these cells against chronic myeloid leukemia cell line K562 t(9:22), 4 pediatrie tumor cell lines [infant acute lymphoblastic leukemia RS4 t(4;ll), THL/AML acute lymphoblastic leukemia REH t(12:21), alveolar rhabdomyosarcoma Rh-Cr t(2;13), and Ewing sarcoma EW-Le t(11;22)], and 2 pediatrie glioblastoma multiforme cultured cell lines (G74 and G77). CIK cells were generated and expanded in culture medium to which interferon y, monoclonal antibody against CD3, and interleukin 2 were added at appropriate times. Cells were counted by flow cytometry. Net lactate dehydrogenase release from target cells incubated with CIK cells was used as an index of CIK cell cytotoxicity against various pediatrie tumor cell lines. Ihe results show that after 21 days in culture CD3*CD56+ CIK cells derived from the 6 pediatrie patients accounted for a median of 28.3% of the entire culture (range, 10.7%-36.4%). Before expansion no such cells were found in any of the 6 children. Median lytic activity rates of CIK cells were 45.5% to 64.5%, rates that contrasted drastically to the lytic activity rates of PBL, which were only 8% to 12%. The findings of the present study are encouraging. They provide information for developing adoptive immunotherapy for future clinical trials with pediatrie cancer patients, particularly those patients with minimal residual disease after intensive chemotherapy or stem cell transplantation (especially nonmyeloablative transplantation procedures).

Generation of a chimeric mouse reconstituted with green fluorescent protein-positive bone marrow cells: A useful model for studying the behavior of bone marrow cells in regeneration in vivo

Abstract: Studies have indicated that bone marrow contains both hematopoietic stem cells and mesenchymal stem cells that can differentiate into a variety of mesenchymal tissues, such as bone, cartilage, muscle, and adipose tissue. Therefore, bone marrow cells are thought to be very useful for cell and gene therapy for various diseases. However, the multipotentiality of these cells remains unclear. To address this issue, we established a chimeric model mouse stably reconstituted with green fluorescent protein (GFP)-marked bone marrow cells. We injected bone marrow cells from GFP-transgenic C57BL/6 mice into the tail veins of recipient wild-type C57BL/6 mice that had been irradiated with a lethal dose of 10 Gy from a cesium source. Microscopic examination and fluorescence-assisted cell sorter (FACS) analysis showed that bone marrow cells, including mesenchymal cells, were almost completely reconstituted with GFP+ cells 5 weeks after transplantation. FACS analysis with lineage-specific antibodies confirmed that the GFP+ cells could differentiate into all types of blood cells. To confirm the usefulness of this mouse model, we studied the role of circulating bone marrow—derived cells in healing of damaged intestine. We performed amputation and anastomosis of the jejunum 10 cm from the pyloric region of the stomach. On the third day after operation, a large number of GFP+ cells were infiltrated in the area of anastomosis, and these cells were positive for CD45 and F4/80 antigens. In 7 days, several cells became negative for CD45 and F4/80 and positive for a smooth muscle actin antigen, which is specific for smooth muscle. This finding suggested that bone marrow-derived cells had differentiated into smooth muscle. Because reconstituted bone marrow cells, as opposed to injected bone marrow cells, behave naturally, this model is ideal for studying the multipotentiality of bone marrow cells in vivo.

Human T-lymphotropic virus type 1 (HTLV-1): persistence and immune control.

Abstract: The human retrovirus human T-lymphotropic virus type 1 (HTLV-1) is associated with two distinct types of disease: the malignancy known as adult T-cell leukemia and a range of chronic inflammatory conditions including the central nervous system disease HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). Until recently, it was believed that HTLV-1 was largely latent in vivo. However, evidence from a number of types of experiments shows that HTLV-1 persistently expresses its genes, and that the “set point” of an individual’s proviral load of HTLV-1 is mainly determined by the efficiency of that individual’s cellular immune response to the virus.These conclusions have two main consequences. First, HTLV-1 may be vulnerable to antiretroviral drug therapy or immunotherapy. Second, HTLV-1 infection has become a useful system to analyze the determinants of the efficiency of the antiviral immune response. Society of Hematology

Importance of CD4+ helper T-cells in antitumor immunity.

Abstract: CD8+ cytotoxic T-lymphocytes are major effector cells involved in immunologically specific tumor destruction in vivo, and CD4+ T-cells are essential for controlling this CD8+ T-cell-dependent tumor eradication. The presence of CD4+ T-cells with distinct functional roles has been recognized. The further understanding of the complexity of antitumor immune responses by CD4+ T-cells may be crucial for designing more effective cancer vaccines.

Monitoring minimal residual disease in leukemia using real-time quantitative polymerase chain reaction for Wilms tumor gene (WT1).

Abstract: We previously showed that Wilms tumor gene (WT1) expression level, measured by quantitative reverse transcriptase polymerase chain reaction (RT-PCR), was useful as an indicator of minimal residual disease (MRD) in leukemia and myelodysplastic syndrome. However, in conventional quantitative RT-PCR (CQ-PCR), RT-PCR must be performed for various numbers of cycles depending onWT1 expression level. In the present study, we developed a new real-time quantitative RT-PCR (RQ-PCR) method for quantitatingWT1 transcripts. Results of intraassay and interassay variability tests demonstrated that the real-timeWT1 assay had high reproducibility.WT1 expression levels measured by the RQ- and the CQ-PCR methods were strongly correlated (r = 0.998). Furthermore, a strong correlation was observed amongWT1 transcript values normalized with 3 different control genes (β-actin,ABL, andglyceraldehyde-3-phosphate dehydrogenase) and between relativeWT1 transcript values withWT1 expression in K562 cells as the reference and absoluteWT1 transcript copy numbers per microgram RNA. WhenWT1 expression andminor bcr-abl expression were concurrently monitored in 2 patients withbcr-abl-positive acute lymphoblastic leukemia, both MRDs changed mostly in parallel, indicating the reliability and validity of our RQ-PCR method. In conclusion, this RQ-PCR method is convenient and reliable for monitoring MRD and enables routine clinical use of aWT1 assay.

Prevalence and clinical significance of hepatitis C virus infection in Thai patients with thalassemia.

Abstract: Hepatitis C virus (HCV) infection is a common cause of liver disease in thalassemia major patients in Western, especially Mediterranean, countries. Its significance in thalassemic patients from Southeast Asia has not been critically evaluated. In this report, we describe our study of the prevalence of HCV infection among Thai patients with thalassemia. The relationships of the infection to blood transfusion and the infection's effects on liver function have also been determined. Of the 104 patients studied, 21 (20.2%) tested positively by enzyme immunoassay for anti-HCV antibody, whereas only 2 patients (2%) had the hepatitis B surface antigen. There was no significant relationship between the presence of anti-HCV antibodies and the number and frequency of blood transfusions. In fact, 2 patients (10%) who tested positive for anti-HCV antibodies had never received transfusions. Patients with anti-HCV antibodies had significantly abnormal liver functions, such as higher levels of serum aspartate aminotransferase (SGOT) and alanine aminotransferase (SGPT) and lower levels of serum albumin, compared with patients without anti-HCV antibodies (P = .021, .017, and .004, respectively). However, there were also significant correlations between iron status as indicated by transferrin saturation or serum ferritin levels and SGOT, SGPT, and gamma-glutamyltransferase (GGT) levels. Moreover, abnormal liver function as represented by elevated levels of SGOT, SGPT, GGT, and serum alkaline phosphatase was observed more frequently in patients with iron overload than in patients with a lower degree of iron burden. The presence of HCV did not alter the effects of iron overload on liver function. The findings suggest that both HCV and iron overload are the main causes of abnormal liver function in Thai patients with thalassemia. The treatment of both problems, if coexisting in patients with thalassemia, is required to prevent progression to chronic liver disease.