bluuebunny/crossref_metadata_2025 huggingface dataset:
Comprehensive banking of sibling donor cord blood for children with malignant and nonmalignant disease
Authors: Reed William , Smith Renée , Dekovic Florinna , Lee Joanna Y. , Saba Julie D. , Trachtenberg Elizabeth , Epstein Joanna , Haaz Steffany , Walters Mark C. , Lubin Bertram H.
Published: December 2002

Banking of cord blood (CB) for unrelated hematopoietic stem cell (HSC) transplantation is well established. However, directed-donor banking of CB for siblings in a current good tissue practices (cGTP) environment has not previously been investigated. Families were eligible for the present study if they were caring for a child with a disorder treatable by HSC transplantation and expecting the birth of a full sibling. We devised standard operating procedures and policies to address eligibility, donor recruitment, donor and recipient evaluation, CB collection, shipping, graft characterization, storage, and release of CB from quarantine. Many of these policies are distinctly different from those established for unrelated-donor CB banks. We enrolled 540 families from 42 states. Collections occurred at several hundred different hospitals. No family was deferred on the basis of health history or infectious disease testing, but departures from standard donor suitability criteria were documented. Disease categories for sibling recipients included malignancy, sickle cell anemia, thalassemia major, nonmalignant hematological conditions, and metabolic errors. Mean CB volume (including anticoagulant) was 103.1 mL; mean nucleated cell count was 8.9 × 108. Cell dose exceeded 1.5 × 107 nucleated cells per kilogram for 90% of banked units. Seventeen units (3.4%) have been transplanted. Sixteen of the 17 CB allograft recipients had stable engraftment of donor cells. Remote-site collection of sibling donor CB can be accomplished with a high success rate and in a cGTP-guided environment. The cellular products have been used successfully for transplantation; their number and characteristics should be adequate to support the first prospective clinical investigations of sibling CB transplantation.
Disruption of Smad5 gene leads to enhanced proliferation of high-proliferative potential precursors during embryonic hematopoiesis
Authors: Liu Bing , Sun Yanxun , Jiang Feizi , Zhang Shuangxi , Wu Ying , Lan Yu , Yang Xiao , Mao Ning
Published: December 2002

SMAD proteins are downstream signal transducers of the transforming growth factor β (TGF-β) superfamily, which serve as pleiotropic regulators in embryonic and adult hematopoiesis. SMAD5, initially considered to mediate bone morphogenetic proteins (BMPs) signals, can also transduce the inhibitory signal of TGF-β1 on proliferation of hematopoietic progenitors derived from human bone marrow. To define its specific role in regulation of primitive multipotential progenitors during early embryonic hematopoiesis, we examined Smad5−/− yolk sacs at E9.0 to 9.5 and detected an elevated number of high-proliferative potential colony-forming cells (HPP-CFCs) with enhanced replating potential. To exclude the possible influence of microenvironmental deficit on embryonic hematopoiesis in vivo, we performed in vitro embryonic stem (ES) cell differentiation assay and investigated the HPP-CFCs in particular. Smad5−/− embryoid bodies (EBs) contained an elevated number of blast colony-forming cells (BL-CFCs), the in vitro equivalent of hemangioblast, in contrast to reduced proliferation of primitive erythroid precursors (Ery/Ps) within the mutant EBs. More importantly, profoundly increased frequency of HPP-CFCs, featured with a gene-dosage effect, was detected within day 6 Smad5−/−EBs compared with the wild type. In addition, Smad5−/−HPP-CFCs displayed enhanced self-renewal capacity and decreased sensitivity to TGF-β1 inhibition, suggesting a critical role of Smad5 in TGF-β1 regulation of embryonic HPP-CFCs. Consistently, reverse transcription-polymerase chain reaction analysis detected alterations of the transcription factors including GATA-2 and AML1 as well as cytokine receptors in Smad5−/− HPP-CFC colonies. Together, these data define an important function of SMAD5 in negative regulation of high-proliferative potential precursors during embryonic hematopoiesis.
Prospective testing for drug-dependent antibodies reduces the incidence of thrombocytopenia observed with the small molecule glycoprotein IIb/IIIa antagonist roxifiban: implications for the etiology of thrombocytopenia
Authors: Seiffert Dietmar , Stern Andrew M. , Ebling William , Rossi Richard J. , Barrett Yu Chen , Wynn Richard , Hollis Gregory F. , He Bokang , Kieras Cathy J. , Pedicord Donna L. , Cromley Debra A. , Hua Tsushung A. , Stein Robert B. , Daly Robert N. , Sferruzza Anthony , Pieniaszek Henry J. , Billheimer Jeffrey T.
Published: December 2002

Thrombocytopenia is a relatively common side effect observed during glycoprotein (GP) IIb/IIIa antagonist therapy. With the oral antagonist roxifiban, we observed thrombocytopenia, defined as 50% reduction of platelets over predose values or below 90 000/μL (9 × 1010/L), with a frequency of 2% (8 of 386). Thrombocytopenia occurred either early (days 2 to 4) or delayed (days 11 to 16). No additional cases were observed with up to 6 months of treatment. Retrospective analysis provided evidence for drug-dependent antibodies (DDABs) to GP IIb/IIIa in 5 of 6 subjects, suggestive of an immune etiology of thrombocytopenia. The hypothesis that excluding patients based on positive DDAB reaction would reduce the frequency of thrombocytopenia was tested. Patients were screened for DDABs during the study qualification period and, overall, 3.9% of the patients were excluded based on pre-existing DDAB concentrations above a statistically defined medical decision limit. An additional 2.6% were excluded based on therapy-related antibody production during the first 2 weeks. With antibody testing, 0.2% of patients (2 of 1044) developed immune-mediated thrombocytopenia. One case developed a rapidly increasing antibody concentration and presented with thrombocytopenia despite discontinuation of roxifiban therapy. The second case was related to a false-negative test result. The frequency of thrombocytopenia was statistically significantly reduced from 2% to 0.2% (P = .0007) comparing nonscreened and screened patients. Testing for DDABs can reduce the frequency of thrombocytopenia in patients treated with roxifiban and, by analogy, other GP IIb/IIIa antagonists. Thus, DDAB testing may be employed to increase the safety of GP IIb/IIIa antagonists.
Heterologous cells cooperate to augment stem cell migration, homing, and engraftment
Authors: Adams Gregor B. , Chabner Karissa T. , Foxall Russell B. , Weibrecht Kathryn W. , Rodrigues Neil P. , Dombkowski David , Fallon Robert , Poznansky Mark C. , Scadden David T.
Published: December 2002

T-lymphocyte depletion of bone marrow grafts compromises engraftment, suggesting a facilitating mechanism provided by the T cells that has been shown to associate with CD8+ but not CD4+ T cells. Explanations for this phenomenon have focused on immune targeting of residual host cells or cytokine production. We provide evidence for an alternative mechanism based on cooperative effects on cell motility. We observed that engraftment of CD34+ cells in a β2-microglobulin–deficient nonobese diabetic/severe combined immunodeficiency (β2m−/− NOD/SCID) mouse model paralleled clinical observations in humans, with an enhancing effect noted from the addition of CD8+ cells but not CD4+ cells. This correlated with CD8+ augmentation of CD34+cell homing to the bone marrow in vivo and CD8+cell–associated increases of CD34+ cell transmigration through a bone marrow endothelial cell line in vitro. The cooperative interaction was not sensitive to brefeldin A inhibition of protein secretion. However, cytochalasin D–induced inhibition of CD8+ cytoskeletal rearrangements abrogated CD34+ transendothelial migration and impaired CD34+ cell homing in vivo. CD8+ cells did not migrate in tandem with CD34+ cells or alter endothelial barrier integrity; rather, they affected phosphotyrosine-mediated signaling in CD34+ cells in response to the chemokine stromal derived factor-1α (SDF-1α). These data demonstrate cell-cell cooperativity between different cell types in mediating chemotactic events and provide one potential explanation for the clinically observed effect of CD8+ cells on bone marrow transplantation. This modification of cell migration by neighboring cells provides broad possibilities for combinatorial effects between cells of different types to influence cell localization.
Early blast clearance by remission induction therapy is a major independent prognostic factor for both achievement of complete remission and long-term outcome in acute myeloid leukemia: data from the German AML Cooperative Group (AMLCG) 1992 Trial
Authors: Kern Wolfgang , Haferlach Torsten , Schoch Claudia , Löffler Helmut , Gassmann Winfried , Heinecke Achim , Sauerland Maria Christina , Berdel Wolfgang , Büchner Thomas , Hiddemann Wolfgang
Published: December 2002

Risk assessment in acute myeloid leukemia (AML) using pretreatment characteristics may be improved by incorporating parameters of early response to therapy. In the 1992 trial of the German AML Cooperative Group (AMLCG), the amount of residual leukemic blasts in bone marrow was assessed one week after the first induction course (day 16 blasts). A total of 449 patients 16 to 76 years of age (median, 53 years) with de novo AML entered the trial and were evaluable. Treatment included TAD/HAM (thioguanine, cytosine arabinoside, and daunorubicin/high-dose cytosine arabinoside and mitoxantrone) double induction, TAD consolidation, and randomly either maintenance therapy or S-HAM consolidation. Cytogenetics were favorable, intermediate, unfavorable and not available in 10.0%, 48.3%, 13.1%, and 28.5%, respectively. Day 16 blasts ranged from 0% to 100% (median, 5%, mean ± SD, 18.6 ± 28.5%). Complete remission (CR) rate was 72.6%, 17.6% had persistent leukemia (PL), and 9.8% succumbed to hypoplastic death. Median overall survival (OS), event-free survival (EFS), and relapse-free survival (RFS) were 18, 9, and 15 months with 28.4%, 21.6%, and 30.1% at 5 years, respectively. As a continuous variable, day 16 blasts were related to CR rate (P < 0.0001), PL rate (P < 0.0001), OS (P < 0.0001), EFS (P < 0.0001), and RFS (P = 0.0049). Multivariate analyses identified the following parameters to be associated with the respective end points. CR rate: day 16 blasts (P < .0001), age (P = .0036), and LDH (P = .0072); OS: unfavorable cytogenetics (P < .0001), day 16 blasts (P < .0001), age (P < .0001), and LDH (P = .0040); EFS: unfavorable cytogenetics (P < .0001), LDH (P < .0001), day 16 blasts (P < .0001), and age (P = .0061); RFS: unfavorable cytogenetics (P < .0001), LDH (P < .0001), and day 16 blasts (P = .0359). The prognostic significance of day 16 blasts is independent of pretherapeutic parameters and predicts outcome even in patients achieving a CR.
An intrinsic thyrotropin-mediated pathway of TNF-α production by bone marrow cells
Authors: Wang Heuy-Ching , Dragoo Jolene , Zhou Qin , Klein John R.
Published: December 2002

Recent studies have identified a role for thyroid-stimulating hormone (TSH; ie, thyrotropin) as an inductive signal for tumor necrosis factor-α (TNF-α) secretion by bone marrow (BM) cells, although the features of that activation pathway have not been defined. Using intracellular TSH staining and enzyme-linked immunoassay for detection of secreted TSH, we demonstrate that TSH synthesis in BM cells occurs within CD45+ (leukocyte common antigen) hematopoietic cells and that the majority of that activity resides in a component of CD11b+ BM cells that are not mature T cells, B cells, or Thy-1+ cells in the BM. Conversely, TSH-responsive BM cells defined by expression of TSH receptor (TSHR) using flow cytometry were selectively associated with a nonerythroid CD11b− lymphocyte precursor population. In vitro culture of magnetic-activated cell sorted CD11b− and CD11b+ cells with titrated amounts of purified TSH resulted in significantly higher levels of TNF-α secretion from CD11b− BM cells compared to non-TSH–treated cells, with no appreciable change in TNF-α production from CD11b+cells. These findings are the first to demonstrate TSH production by BM hematopoietic cells, and they demonstrate that TSH may be involved in the regulation of TNF-α by CD11b− BM cells. They also indicate that TSH-mediated regulation of TNF-α secretion within the BM most likely operates through an intrinsic network of TSH production and use between different types of BM cells, and they suggest that local TSH may be an important homeostatic regulator of hematopoiesis mediated by TNF-α.
Imatinib mesylate therapy in newly diagnosed patients with Philadelphia chromosome–positive chronic myelogenous leukemia: high incidence of early complete and major cytogenetic responses
Authors: Kantarjian Hagop M. , Cortes Jorge E. , O'Brien Susan , Giles Francis , Garcia-Manero Guillermo , Faderl Stefan , Thomas Deborah , Jeha Sima , Rios Mary Beth , Letvak Laurie , Bochinski Kathy , Arlinghaus Ralph , Talpaz Moshe
Published: December 2002

Fifty patients with Philadelphia chromosome–positive (Ph+) chronic myelogenous leukemia (CML) in early chronic phase received imatinib mesylate, 400 mg orally daily. After a median follow-up of 9 months, 49 patients (98%) achieved a complete hematologic response and 45 patients (90%) achieved a major cytogenetic response, complete in 36 patients (72%). Compared with similar patients who received interferon-α with or without hydroxyurea or other interferon-α combination regimens, those receiving imatinib mesylate had higher incidences of complete and major (Ph < 35%) cytogenetic responses at 3 months (34% and 74% versus 1%-4% and 9%-24%, respectively), 6 months (52% and 80% versus 3%-7% and 11%-28%, respectively), and 9 months (60% and 77% versus 5%-11% and 14%-30%, respectively; P < .001). Competitive quantitative polymerase chain reaction (QPCR) studies at 9 months showed a median QPCR value (ratio of BCR-ABL/ABL transcripts × 100) of 0.59% overall and of 0.24% (range, 0.001%-29.5%) for complete cytogenetic response.
Endogenous retroviral sequence is fused to FGFR1 kinase in the 8p12 stem-cell myeloproliferative disorder with t(8;19)(p12;q13.3)
Authors: Guasch Géraldine , Popovici Cornel , Mugneret Francine , Chaffanet Max , Pontarotti Pierre , Birnbaum Daniel , Pébusque Marie-Josèphe
Published: December 2002

FGFR1, a transmembrane receptor tyrosine kinase for fibroblast growth factors, is constitutively activated by chromosomal translocations in an atypical stem-cell myeloproliferative disorder. The FGFR1 tyrosine domain is fused to dimerization domains encoded by 4 alternative genes: FOP at 6q27, CEP110 at 9q33,FIM/ZNF198 at 13q12, and BCR at 22q11. In this study, we report the molecular cloning of the t(8;19)(p12;q13.3), the fifth translocation associated with this syndrome. Reverse transcriptase–polymerase chain reaction (RT-PCR) analysis and fluorescence in situ hybridization (FISH) demonstrated that the translocation resulted in a long terminal repeat of human endogenous retrovirus gene (HERV-K)/fibroblast growth factor receptor 1 (FGFR1) fusion transcript that incorporated 5′ sequences from HERV-K fused in frame to 3′ FGFR1 sequences encoding the kinase domain. RT-PCR detected only 1 of the 2 possible fusion transcripts,HERV-K/FGFR1.
LF 15-0195 immunosuppressive agent enhances activation-induced T-cell death by facilitating caspase-8 and caspase-10 activation at the DISC level
Authors: Ducoroy Patrick , Micheau Olivier , Perruche Sylvain , Dubrez-Daloz Laurence , de Fornel Daniel , Dutartre Patrick , Saas Philippe , Solary Eric
Published: December 2002

The deoxyspergualin derivative LF 15-0195 has demonstrated some efficacy in animal models of autoimmune and graft-versus-host diseases and is currently tested in clinics. The molecular mechanisms of LF 15-0195 immunosuppressive activity remained unknown. We show that exposure to LF 15-0195 sensitizes Jurkat T cells to apoptosis induced by an agonistic anti-CD95 antibody (CH11 clone) and by the cytokine TNF-related apoptosis-inducing ligand. LF 15-0195 does not demonstrate any significant effect on the postmitochondrial activation of caspases, nor does it modify overall expression of CD95, Fas-associated death domain, and procaspase-8. The compound facilitates the recruitment of these molecules to the death-inducing signaling complex (DISC) and enhances caspase-8 and -10 activation, thus increasing cytochrome c and direct IAP binding with low pI (DIABLO)/Smac mitochondrial release. LF 15-0195 also sensitizes Jurkat T cells to CD3-mediated apoptosis, an in vitro model for activation-induced T-cell death (AICD). LF 15-0195–mediated sensitization to AICD was further confirmed in human peripheral T cells exposed to anti-CD3 antibodies, then cultured in the presence of interleukin-2. In these cells, LF 15-0195 increased apoptosis triggered by either anti-CD95 antibodies or CD3 restimulation, whereas no effect was observed on “passive apoptosis.” Finally, in bone marrow recipient mice, LF 15-0195 enhanced allogeneic donor T-cell death, which required a functional CD95 pathway. These results suggest that LF 15-0195 sensitizes T cells to AICD by increasing caspase activation at the DISC level in response to CD95 engagement. This original mechanism, together with LF 15-0195 efficacy in various disease models, makes this compound a promising immunosuppressive drug.
Interferon-α, but not the ABL-kinase inhibitor imatinib (STI571), induces expression of myeloblastin and a specific T-cell response in chronic myeloid leukemia
Authors: Burchert Andreas , Wölfl Stefan , Schmidt Manuel , Brendel Cornelia , Denecke Barbara , Cai Dali , Odyvanova Larissa , Lahaye Tanja , Müller Martin C. , Berg Thomas , Gschaidmeier Harald , Wittig Burghardt , Hehlmann Rüdiger , Hochhaus Andreas , Neubauer Andreas
Published: December 2002

Chronic myeloid leukemia (CML) is a clonal disease of hematopoietic stem cells caused by a reciprocal translocation of the long arms of chromosomes 9 and 22. In human leukocyte antigen A*0201+ (HLA-A*0201+) individuals, response after interferon-α (IFN-α) was shown to be associated with the emergence of CML-specific cytotoxic T cells that recognize PR-1, a myeloblastin (MBN)–derived nonapeptide. In contrast, imatinib potently induces remissions from CML by specific inhibition of the ABL tyrosine kinase. Here, we explored molecular regulations associated with CML responses under different treatment forms using cDNA-array. Expression of MBN was found to be down-regulated in remission under imatinib therapy (0 of 7MBN+ patients). In contrast, MBNtranscription was readily detectable in the peripheral blood in 8 of 8 tested IFN-α patients in complete remission (P = .0002). IFN-α–dependent MBNtranscription was confirmed in vitro by stimulation of peripheral blood mononuclear cells (PBMCs) with IFN-α and by IFN-α–mediated activation of the MBN promoter in reporter gene assays. Finally, with the use of HLA-A*0201–restricted,MBN-specific tetrameric complexes, it was demonstrated that all of 4 IFN-α–treated patients (100%), but only 2 of 11 imatinib patients (19%), in complete hematological or cytogenetic remission developed MBN-specific cytotoxic T cells (P = .011). Together, the induction of MBNexpression by IFN-α, but not imatinib, may contribute to the specific ability of IFN-α to induce an MBN-specific T-cell response in CML patients. This also implies that the character of remissions achieved with either drug may not be equivalent and therefore a therapy modality combining IFN-α and imatinib may be most effective.
Differential chemokine expression profiles in human peripheral blood T lymphocytes: dependence on T-cell coreceptor and calcineurin signaling
Authors: Cristillo Anthony D. , Macri Mirtha J. , Bierer Barbara E.
Published: December 2002

The chemokine superfamily consists of small (8-10 kDa) molecules that function to attract, selectively, different subsets of leukocytes. Binding of chemokines to their appropriate G-protein–coupled receptors is necessary for primary immune responses and for homing of leukocytes to lymphoid tissues. Here, we have characterized the signaling pathways in primary T lymphocytes that regulate chemokine gene induction using an RNase protection assay. Dependence on stimulation through the coreceptor CD28 and sensitivity to the calcineurin inhibitors cyclosporine and tacrolimus were studied using purified human peripheral blood lymphocytes. Lymphotactin (Ltn), macrophage inflammatory protein (MIP)–1α, and MIP-1β were all rapidly induced and sensitive to cyclosporine treatment. At later time points, the expression of MIP-1α and MIP-1β, but not of Ltn, was restored despite the inhibition of calcineurin activity. By contrast, the induction of interleukin-8 was delayed and was found to be cyclosporine insensitive. Calcineurin activity of IP-10 mRNA induction was contingent on the specific T-cell stimulation conditions, suggesting that IP-10 expression is modulated by calcineurin-dependent and -independent signaling pathways. Differential chemokine expression profiles result from the engagement of T-cell coreceptors and the requirement for, and the dependence on, calcineurin phosphatase activity.
Signal transducer and activator of transcription 5a (STAT5a) is required for eosinophil differentiation of human cord blood–derived CD34+ cells
Authors: Buitenhuis Miranda , Baltus Belinda , Lammers Jan-Willem J. , Coffer Paul J. , Koenderman Leo
Published: December 2002

Signal transducers and activators of transcription (STATs) have been reported to play a critical role in the differentiation of several myeloid cell lines, although the importance of STATs in the differentiation of primary human hematopoietic cells remains to be established. Terminal eosinophil differentiation is induced by interleukin-5 (IL-5), which has also been demonstrated to activate STAT5. We have investigated whether STAT5 plays a critical role during eosinophil differentiation using umbilical cord blood–derived CD34+ cells. In this ex vivo system, STAT5 expression and activation are high early during differentiation, and STAT5 protein expression is down-regulated during the final stages of eosinophil differentiation. Retroviral transductions were performed to ectopically express wild-type and dominant-negative STAT5a (STAT5aΔ750) in CD34+ cells. Transduction of cells with STAT5a resulted in enhanced proliferation compared with cells transduced with empty vector alone. Interestingly, ectopic expression of STAT5a also resulted in accelerated differentiation. In contrast, ectopic expression of STAT5aΔ750 resulted in a block in differentiation, whereas proliferation was also severely inhibited. Similar results were obtained with dominant-negative STAT5b. Forced expression of STAT5a enhanced expression of the STAT5 target genes Bcl-2 andp21WAF/Cip1, suggesting they may be important in STAT5a-mediated eosinophil differentiation. These results demonstrate that STAT5 plays a critical role in eosinophil differentiation of primary human hematopoietic cells.
VEGFR-3 and CD133 identify a population of CD34+ lymphatic/vascular endothelial precursor cells
Authors: Salven Petri , Mustjoki Satu , Alitalo Riitta , Alitalo Kari , Rafii Shahin
Published: December 2002

Human CD133 (AC133)+CD34+ stem and progenitor cells derived from fetal liver and from bone marrow and blood incorporate a functional population of circulating endothelial precursor cells. Vascular endothelial growth factor receptor 3 (VEGFR-3) regulates cardiovascular development and physiological and pathological lymphangiogenesis and angiogenesis. However, the origin of VEGFR-3+ endothelial cells (ECs) and the mechanisms by which these cells contribute to postnatal physiological processes are not known, and the possible existence of VEGFR-3+ lymphatic or vascular EC progenitors has not been studied. Using monoclonal antibodies to the extracellular domain of VEGFR-3, we show that 11% ± 1% of CD34+ cells isolated from human fetal liver, 1.9% ± 0.8% CD34+ cells from human cord blood, and 0.2% ± 0.1% of CD34+ cells from healthy adult blood donors are positive for VEGFR-3. CD34+VEGFR-3+ cells from fetal liver coexpress the stem/precursor cell marker CD133 (AC133). Because mature ECs do not express CD133, coexpression of VEGFR-3 and CD133 on CD34+cells identifies a unique population of stem and progenitor cells. Incubation of isolated CD34+VEGFR-3+ cells in EC growth medium resulted in a strong proliferation (40-fold in 2 weeks) of nonadherent VEGFR-3+ cells. Plating of these cells resulted in the formation of adherent VEGFR-3+Ac-LDL+ (Ac-LDL = acetylated low-density lipoprotein) EC monolayers expressing various vascular and lymphatic endothelial-specific surface markers, including CD34, VE-cadherin, CD51/61, CD105, LYVE-1, and podoplanin. These data demonstrate that human CD34+CD133+ cells expressing VEGFR-3 constitute a phenotypically and functionally distinct population of endothelial stem and precursor cells that may play a role in postnatal lymphangiogenesis and/or angiogenesis.
Transendothelial migration leads to protection from starvation-induced apoptosis in CD34+CD14+circulating precursors: evidence for PECAM-1 involvement through Akt/PKB activation
Authors: Ferrero Elisabetta , Belloni Daniela , Contini Paola , Foglieni Chiara , Ferrero Maria Elena , Fabbri Monica , Poggi Alessandro , Zocchi Maria Raffaella
Published: December 2002

In the present paper we show that transendothelial migration of a subset of CD14+ circulating leukocytes, coexpressing the CD34 precursor marker, leads to protection from the apoptosis that follows growth factor(s) withdrawal. The resistance of this cell subset to starvation-induced programmed cell death, lasting from 48 to 96 hours, is accompanied by a rise of mitochondrial adenosine triphosphate (ATP), a high nicotinamide adenine dinucleotide (NAD)/reduced nicotinamide adenine dinucleotide (NADH) ratio, and by the up-regulation of expression of the antiapoptotic proteins Bcl-2 and Bcl-X, together with an increase in the cytoplasmic, inactive, form of Bax. This suggests that protection from apoptosis is due to the preservation of mitochondrial function(s). Interestingly, ligation of the platelet endothelial cell adhesion molecule-1 (PECAM-1), which drives CD14+CD34+ transendothelial migration, leads to an increase in Bcl-2 A1 and Bcl-X intracellular content, and to protection from starvation-induced apoptosis. This event is dependent on the engagement of phosphatidylinositol-3 kinase and activation of Akt/PKB that is known to contribute to Bcl-2 and Bcl-X induction. These data point to a critical role of endothelium in preventing the apoptotic program triggered by starvation, possibly inducing a prolonged survival of antigen presenting cell precursors, in order to allow recirculation of these cells and localization to the site of priming of T lymphocytes.
Hypoxic up-regulation of erythroid 5-aminolevulinate synthase
Authors: Hofer Thomas , Wenger Roland H. , Kramer Marianne F. , Ferreira Gloria C. , Gassmann Max
Published: December 2002

The erythroid-specific isoform of 5-aminolevulinate synthase (ALAS2) catalyzes the rate-limiting step in heme biosynthesis. The hypoxia-inducible factor–1 (HIF-1) transcriptionally up-regulates erythropoietin, transferrin, and transferrin receptor, leading to increased erythropoiesis and hematopoietic iron supply. To test the hypothesis that ALAS2 expression might be regulated by a similar mechanism, we exposed murine erythroleukemia cells to hypoxia (1% O2) and found an up to 3-fold up-regulation of ALAS2 mRNA levels and an increase in cellular heme content. A fragment of the ALAS2 promoter ranging from −716 to +1 conveyed hypoxia responsiveness to a heterologous luciferase reporter gene construct in transiently transfected HeLa cells. In contrast, iron depletion, known to induce HIF-1 activity but inhibit ALAS2 translation, did not increase ALAS2 promoter activity. Mutation of a previously predicted HIF-1–binding site (−323/−318) within this promoter fragment and DNA-binding assays revealed that hypoxic up-regulation is independent of this putative HIF-1 DNA-binding site.
Most antiviral CD8 T cells during chronic viral infection do not express high levels of perforin and are not directly cytotoxic
Authors: Zhang Dong , Shankar Premlata , Xu Zhan , Harnisch Brooke , Chen Gang , Lange Christoph , Lee Sandra J. , Valdez Hernan , Lederman Michael M. , Lieberman Judy
Published: December 2002

Despite the frequency of HIV-specific CD8 T cells, most HIV-infected patients do not control viral replication without antiviral drugs. Although CD8 T cells are important in containing acute HIV and simian immunodeficiency virus (SIV) infection, CD8 T-cell functions are compromised in chronic infection. To investigate whether functional deficits are specific to HIV, the phenotypic and functional properties of HIV, Epstein-Barr virus (EBV), and cytomegalovirus (CMV)–specific CD8 T cells, labeled with HLA A2.1 or B8 tetramers, were compared in 35 HIV-infected and 9 healthy donors. Cytotoxic T lymphocytes express the cytolytic molecules perforin and granzymes, and are thought to be CD45RA+CD27−. Although most HIV- specific cells are antigen experienced and express granzyme A (median, 85%), few express high levels of perforin (median, 10%) or CD45RA (median, 14%) or have down-modulated CD27 (median, 12%). Perforin expression by HIV-specific cells is not significantly different from that of EBV- or CMV-specific cells in the same donors or in healthy donors. EBV- and CMV-specific cells, like HIV-specific cells, are often not cytotoxic when tested directly ex vivo. HIV-specific T-cell expression of other phenotypic markers is similar to that of EBV- and CMV-specific CD8 T cells in healthy donors. However, CMV-specific cells (and, to a lesser extent, EBV-specific cells) in HIV-infected donors are more likely to be CD27−, CD45RA+, and GzmA+. These results suggest that the chance to eradicate an infection by T-cell–mediated lysis may be undermined once an infection becomes chronic. Impaired antiviral cytotoxicity during chronic infection is not specific to HIV but likely represents the immune response to chronic antigenic exposure.
Differential distribution and internal translation efficiency of hepatitis C virus quasispecies present in dendritic and liver cells
Authors: Laporte Julien , Bain Christine , Maurel Patrick , Inchauspe Genevieve , Agut Henri , Cahour Annie
Published: December 2002

Hepatitis C virus (HCV) is predominantly a hepatotropic virus. Nonetheless, there is mounting evidence that hematopoietic cells may support HCV replication. The HCV 5′ untranslated region (5′UTR), responsible for initiation of viral translation, via an internal ribosome entry site (IRES), has been previously described to contain specific nucleotide substitutions when cultured in infected lymphoid cells. Our purpose was to establish whether the 5′UTR polymorphism of quasispecies from 3 cell compartments (liver, peripheral blood mononuclear cells [PBMG], and monocyte-derived dendritic cells [DCs]) of a patient chronically infected with HCV1b affects the corresponding translational efficiencies and thus the capacity for replication. The 5′UTR polymorphism was characterized by identification of changes at 3 crucial sites as compared with the reference nucleotide (nt) sequence: a G insertion between positions 19 and 20, a C>A substitution at position 204 and a G>A substitution at position 243. The quasispecies detected in DCs was unique and differed from those present in the liver, suggesting a particular tropism of HCV quasispecies for DCs. Moreover, its translational activity was significantly impaired when compared with those from liver and PBMCs in different cell lines. This impairment was thoroughly confirmed in primary cultures of both human hepatocytes and monocyte-derived DCs. Taken together, our data lend support both to a specific location and impaired replication of HCV quasispecies in DCs, which could be related to viral persistence and perturbation of DC function in chronically infected patients.
CCR7-mediated physiological lymphocyte homing involves activation of a tyrosine kinase pathway
Authors: Stein Jens V. , Soriano Silvia F. , M'rini Christine , Nombela-Arrieta César , González de Buitrago Gonzalo , Rodrı́guez-Frade José Miguel , Mellado Mario , Girard Jean-Philippe , Martı́nez-A. Carlos
Published: December 2002

Homing of blood-borne lymphocytes to peripheral lymph nodes (PLNs) is a multistep process dependent on the sequential engagement of L-selectin, which mediates lymphocyte rolling along the luminal surface of high endothelial venules (HEVs), followed by activation of lymphocyte integrins and transmigration through HEVs. Within lymphoid tissue, B and T lymphocytes then migrate toward specific microenvironments such as B-cell follicles and the paracortex, respectively. The lymphocyte-expressed chemokine receptor CCR7 is playing an important role during this process, as its HEV-presented ligands CCL19 and CCL21 can trigger rapid integrin activation under flow in addition to inducing a chemotactic response, which may participate in transmigration and/or interstitial migration. Here, we report that Tyrphostin (Tyr) AG490, a pharmacological inhibitor of Janus family tyrosine kinases (Jaks), blocked the chemotactic response of primary mouse lymphocytes to CCL19 and CCL21 in a dose-dependent manner. Furthermore, Tyr AG490 inhibited rapid CCL21-mediated up-regulation of α4 and β2 integrin adhesiveness in static adhesion assays and under physiological flow, whereas adhesion induced by phorbol myristate acetate remained unaltered. Using intravital microscopy of subiliac PLNs in mice, we found that adoptively transferred Tyr AG490–treated lymphocytes adhered significantly less in HEVs compared with control cells, although L-selectin–mediated rolling was similar in both samples. Finally, we observed rapid Jak2 phosphorylation in CCL21-stimulated primary mouse lymphocytes. Thus, our study suggests a role for Jak tyrosine kinases during CCR7-mediated lymphocyte recirculation.
Monoglycerides induce apoptosis in human leukemic cells while sparing normal peripheral blood mononuclear cells
Authors: Philippoussis Fabianne , Arguin Chantal , Mateo Véronique , Steff Ann-Muriel , Hugo Patrice
Published: December 2002

A major drawback of the current antineoplastic treatments is their lack of specificity toward cancer cells, because they are most often cytotoxic to normal cells, thus creating related side effects. Hence, the identification of new apoptosis-inducing agents, specifically targeting malignant cells while sparing their normal counterparts, is of crucial interest. We show here that monoglycerides, a family of lipids consisting of a single fatty acid attached to a glycerol backbone, induce cell death in several human leukemic cell lines. Importantly, treatment of primary leukemic cells, obtained from B-cell chronic lymphocytic leukemia patients, resulted in rapid apoptosis. In striking contrast, resting or activated human peripheral blood mononuclear cells from healthy individuals were resistant to the same treatment. Therefore, these compounds could represent potential antileukemic drugs or could allow for the design of novel therapeutic agents applied to leukemia.
Early macrophage influx to sites of cutaneous granuloma formation is dependent on MIP-1α/β released from neutrophils recruited by mast cell–derived TNFα
Authors: von Stebut Esther , Metz Martin , Milon Genevieve , Knop Jürgen , Maurer Marcus
Published: December 2002

Macrophages (MΦ) play a crucial role in the development of cutaneous granulomas (CGs) initiated by foreign bodies or invasive microorganisms. However, little is known about how MΦ are recruited to sites of CG formation. To test whether mast cells (MCs) contribute to early MΦ recruitment to developing granulomas, CGs were induced in MC-deficient KitW/KitW-v mice by injection of polyacrylamide gel (PAG).KitW/KitW-v mice as well as mice deficient in the MC product TNFα exhibited markedly reduced MΦ numbers in CGs. MΦ recruitment was restored inKitW/KitW-v mice reconstituted with MCs from Kit+/+ or TNFα+/+, but not from TNFα−/− mice. MC-TNFα–dependent MΦ influx required prior recruitment of MIP-1α/β–producing neutrophils (PMNs), as PMN depletion before induction of CGs completely inhibited MΦ influx, which was restored after reconstitution with PMN supernatants. These findings indicate that MΦ recruitment to cutaneous PAG- induced granulomas is the result of a sequence of inflammatory processes initiated by MC-derived TNFα followed by PMN influx and MIP-1a/β release.
An Arg760Cys mutation in the consensus sequence of the von Willebrand factor propeptide cleavage site is responsible for a new von Willebrand disease variant
Authors: Casonato Alessandra , Sartorello Francesca , Cattini Maria Grazia , Pontara Elena , Soldera Carmen , Bertomoro Antonella , Girolami Antonio
Published: December 2002

We describe a von Willebrand disease (VWD) variant characterized by the persistence of von Willebrand factor (VWF) propeptide as a result of a C>T transition at nucleotide 2527 in exon 17 of the VWF gene. This mutation, which was present in the proband and his father, predicts the substitution of Cys for Arg at position 760 of pre–pro-VWF, 4 residues before the propeptide cleavage site belonging to a consensus sequence for substrate recognition by the processing enzyme paired dibasic amino acid–cleaving enzyme (PACE)/furin. Sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS-PAGE) documented the presence of both processed and unprocessed VWF in the patient's plasma, with unprocessed VWF relatively less represented. The patient's hemostatic phenotype was characterized by a mild decrease in plasma factor VIII (FVIII) and VWF, a decrease in plasma VWF multimers, and a mild reduction in the FVIII binding capacity of VWF. The FVIII binding defect was more pronounced in the proband than in the father because he also inherited the type 2N Arg91Gln mutation from his mother. The persistence of VWF propeptide did not impair VWF synthesis because platelet VWF content was normal, nor did it compromise VWF storage in endothelial cells, because of the normal post–1-deamino-8-D-arginine vasopressin (DDAVP) increase in plasma VWF. Coexpression of wild-type and Arg760Cys VWF into a Furin-producing BHK cell line resulted in decreased VWF secretion and a defect in the FVIII binding capacity of VWF, together with the persistence of VWF propeptide. These findings confirm that a normal consensus sequence for VWF propeptide cleavage and efficient cleavage are required in vivo for normal FVIII binding capacity of VWF.
Essential role for ICSBP in the in vivo development of murine CD8α+ dendritic cells
Authors: Aliberti Julio , Schulz Oliver , Pennington Daniel J. , Tsujimura Hideki , Reis e Sousa Caetano , Ozato Keiko , Sher Alan
Published: December 2002

Interferon (IFN) consensus sequence-binding protein (ICSBP) is an important transcription factor regulating proinflammatory cytokine production and the development of mononuclear phagocytes in vitro. Here we analyzed the role of ICSBP in the in vivo differentiation of 3 major subsets of murine dendritic cells (DCs). We found that ICSBP is predominantly expressed by the CD8α+ subset, and more important, that ICSBP−/− mice have a profound and selective deficiency in CD8α+ DEC205+ DCs in lymphoid tissues. Studies using wild-type/ICSBP−/−chimeras revealed that this defect in CD8α+ DC development is intrinsic to bone marrow–derived progenitors and not dependent on ICSBP expression in the nonhemopoietic compartment. Because DC precursor frequencies are unaltered in the bone marrow of ICSBP−/− mice, ICSBP appears to function by regulating CD8α+ DC differentiation downstream from the generation of common DC progenitors. Although CD8α− DCs are present in normal numbers in ICSBP−/− animals, up-regulation of CD40, CD80, and major histocompatibility complex (MHC) class II expression was found to be impaired in this subset after in vivo microbial stimulation. Together these results demonstrate that ICSBP is critically required for the in vivo differentiation of CD8α+ DCs and may also influence the functional maturation of the CD8α− subsets.
Ribosomal protein S19 expression during erythroid differentiation
Authors: Da Costa Lydie , Narla Goutham , Willig Thiébaut-Noel , Peters Luanne L. , Parra Marilyn , Fixler Jason , Tchernia Gil , Mohandas Narla
Published: December 2002

The gene encoding ribosomal protein S19 (RPS19) has been shown to be mutated in 25% of the patients affected by Diamond-Blackfan anemia (DBA), a congenital erythroblastopenia. As the role of RPS19 in erythropoiesis is still to be defined, we performed studies on RPS19 expression during terminal erythroid differentiation. Comparative analysis of the genomic sequences of human and mouse RPS19genes enabled the identification of 4 conserved sequence elements in the 5′ region. Characterization of transcriptional elements allowed the identification of the promoter in the human RPS19 gene and the localization of a strong regulatory element in the third conserved sequence element. By Northern blot and Western blot analyses of murine splenic erythroblasts infected with the anemia-inducing strain Friend virus (FAV cells), RPS19 mRNA and protein expression were shown to decrease during terminal erythroid differentiation. We anticipate that these findings will contribute to further development of our understanding of the contribution of RPS19 to erythropoiesis.
Interferon-γ switches monocyte differentiation from dendritic cells to macrophages
Authors: Delneste Yves , Charbonnier Peggy , Herbault Nathalie , Magistrelli Giovanni , Caron Gersende , Bonnefoy Jean-Yves , Jeannin Pascale
Published: December 2002

Human monocytes differentiate into dendritic cells (DCs) or macrophages according to the nature of environmental signals. Monocytes stimulated with granulocyte-macrophage colony-stimulating factor (GM-CSF) plus interleukin 4 (IL-4) yield DCs. We tested here whether interferon-γ (IFN-γ), a potent activator of macrophages, may modulate monocyte differentiation. Addition of IFN-γ to IL-4 plus GM-CSF–stimulated monocytes switches their differentiation from DCs to CD14−CD64+ macrophages. IFN-γ increases macrophage colony-stimulating factor (M-CSF) and IL-6 production by IL-4 plus GM-CSF–stimulated monocytes by acting at the transcriptional level and acts together with IL-4 to up-regulate M-CSF but not IL-6 production. IFN-γ also increases M-CSF receptor internalization. Results from neutralizing experiments show that both M-CSF and IL-6 are involved in the ability of IFN-γ to skew monocyte differentiation from DCs to macrophages. Finally, this effect of IFN-γ is limited to early stages of differentiation. When added to immature DCs, IFN-γ up-regulates IL-6 but not M-CSF production and does not convert them to macrophages, even in the presence of exogenous M-CSF. In conclusion, IFN-γ shifts monocyte differentiation to macrophages rather than DCs through autocrine M-CSF and IL-6 production. These data show that IFN-γ controls the differentiation of antigen-presenting cells and thereby reveals a new mechanism by which IFN-γ orchestrates the outcome of specific immune responses.
Centrosome aberrations in acute myeloid leukemia are correlated with cytogenetic risk profile
Authors: Neben Kai , Giesecke Christian , Schweizer Silja , Ho Anthony D. , Krämer Alwin
Published: December 2002

Genetic instability is a common feature in acute myeloid leukemia (AML). Centrosome aberrations have been described as a possible cause of aneuploidy in many human tumors. To investigate whether centrosome aberrations correlate with cytogenetic findings in AML, we examined a set of 51 AML samples by using a centrosome-specific antibody to pericentrin. All 51 AML samples analyzed displayed numerical and structural centrosome aberrations (36.0% ± 16.6%) as compared with peripheral blood mononuclear cells from 21 healthy volunteers (5.2% ± 2.0%; P < .0001). In comparison to AML samples with normal chromosome count, the extent of numerical and structural centrosome aberrations was higher in samples with numerical chromosome changes (50.5% ± 14.2% versus 34.3% ± 12.2%; P < .0001). When the frequency of centrosome aberrations was analyzed within cytogenetically defined risk groups, we found a correlation of the extent of centrosome abnormalities to all 3 risk groups (P = .0015), defined as favorable (22.5% ± 7.3%), intermediate (35.3% ± 13.1%), and adverse (50.3% ± 15.6%). These results indicate that centrosome defects may contribute to the acquisition of chromosome aberrations and thereby to the prognosis in AML.
Regulation of Akt-dependent cell survival by Syk and Rac
Authors: Jiang Kun , Zhong Bin , Ritchey Connie , Gilvary Danielle L. , Hong-Geller Elizabeth , Wei Sheng , Djeu Julie Y.
Published: December 2002

Interleukin-2 (IL-2) prevents cell apoptosis and promotes survival, but the involved mechanisms have not been completely defined. Although phosphatidylinositide 3-kinase (PI 3-kinase) has been implicated in IL-2–mediated survival mechanisms, none of the 3 chains of the IL-2 receptor (IL-2R) expresses a binding site for PI 3-kinase. However, IL-2Rβ does express a Syk-binding motif. By using an IL-2–dependent natural killer (NK) cell line, followed by validation of the results in fresh human NK cells, we identified Syk as a critical effector essential for IL-2–mediated prosurvival signaling in NK cells. Down-regulation of Syk by piceatannol treatment impaired NK cellular viability and induced prominent apoptosis as effectively as suppression of PI 3-kinase function by LY294002. Expression of kinase-deficient Syk or pretreatment with piceatannol markedly suppressed IL-2–stimulated activation of PI 3-kinase and Akt, demonstrating that Syk is upstream of PI 3-kinase and Akt. However, constitutively active PI 3-kinase reversed this loss of Akt function caused by kinase-deficient Syk or piceatannol. Thus, Syk appears to regulate PI 3-kinase, which controls Akt activity during IL-2 stimulation. More important, we observed Rac1 activation by IL-2 and found that it mediated PI 3-kinase activation of Akt. This conclusion came from experiments in which dominant-negative Rac1 significantly decreased IL-2–induced Akt activation, whereas constitutively active Rac1 reelevated Akt activity not only in Syk-impaired but also in PI 3-kinase–impaired NK cells. These results constitute the first report of a Syk → PI3K → Rac1 → Akt signal cascade controlled by IL-2 that mediates NK cell survival.
Evidence that the red cell skeleton protein 4.2 interacts with the Rh membrane complex member CD47
Authors: Mouro-Chanteloup Isabelle , Delaunay Jean , Gane Pierre , Nicolas Virginie , Johansen Mette , Brown Eric J. , Peters Luanne L. , Le Van Kim Caroline , Cartron Jean Pierre , Colin Yves
Published: December 2002

Rhnull red cells are characteristically stomato-spherocytic. This and other evidence suggest that the Rh complex represents a major attachment site between the membrane lipid bilayer and the erythroid skeleton. As an attempt to identify the linking protein(s) between the red cell skeleton and the Rh complex, we analyzed the expression of Rh, RhAG, CD47, LW, and glycophorin B proteins in red cells from patients with hereditary spherocytosis associated with complete protein 4.2 deficiency but normal band 3 (4.2(-)HS). Flow cytometric and immunoblotting analysis revealed a severe reduction of CD47 (up to 80%) and a slower mobility of RhAG on sodium dodecyl sulfate–polyacrylamide gel electrophoresis, possibly reflecting an overglycosylation state. Unexpectedly, 4.2−/− mice, which are anemic, displayed a normal red cell expression of CD47 and RhAG. These results suggest that human protein 4.2, through interaction with CD47, is involved in the skeleton linkage and/or membrane translocation of the Rh complex. However, these potential role(s) of protein 4.2 might be not conserved across species. Finally, the absence or low expression of red cell CD47 in CD47−/− mice and in some humans carrying RHCEgene variants (D--, D.., and RN), respectively, had no detectable effect on protein 4.2 and RhAG expression. Since these cells are morphologically normal with no sign of hemolysis, it is assumed that CD47 deficiency per se is not responsible for the cell shape abnormalities and for the compensated hemolytic anemia typical of 4.2(-) and Rhnull red cells.