bluuebunny/crossref_metadata_2025 huggingface dataset:
The interaction of human peripheral blood eosinophils with bacterial lipopolysaccharide is CD14 dependent
Authors: Plötz Sabine G. , Lentschat Arnd , Behrendt Heidrun , Plötz Werner , Hamann Lutz , Ring Johannes , Rietschel Ernst Th. , Flad Hans-Dieter , Ulmer Artur J.
Published: July 2002

Bacterial lipopolysaccharide (LPS, endotoxin) is a ubiquitous component of dust and air pollution and is suspected to contribute after inhalation to an activation of eosinophils in bronchial tissues of asthmatic patients, provoking inflammatory and allergic processes. We were therefore interested in the interaction of eosinophil granulocytes with LPS and have examined the activation of and uptake to human peripheral blood eosinophils by LPS. Eosinophils were stimulated by LPS and the endotoxic component lipid A and the release of tumor necrosis factor alpha (TNF-α) and of the eosinophil-specific granule protein eosinophil cationic protein (ECP) was estimated. The results show induction of TNF-α and ECP-release by LPS and lipid A in a dose-dependent manner. Anti-CD14 monoclonal antibody (moAb) (clone MEM-18) and the synthetic lipid A partial structure 406 blocked the release of TNF-α and ECP by LPS-stimulated eosinophils. Studies with radioactively labeled LPS showed dose-dependent uptake of3H-LPS to eosinophils. The 3H-LPS uptake was found to be specific because preincubation with unlabeled LPS, compound 406 and also anti-CD14 antibodies inhibited uptake of3H-LPS to eosinophil granulocytes. By flow cytometry using anti-CD14 moAb and by reverse transcriptase-polymerase chain reaction (RT-PCR) technique, CD14 expression was detectable. Furthermore, messenger RNA (mRNA) expression of Toll-like receptors (TLR) 2 and TLR 4 was detected, indicating the presence of these CD14 coreceptors. The results indicate that eosinophils can take up LPS and can be stimulated by LPS in a CD14-dependent manner. Hence, in addition to allergens, eosinophils interact with endotoxin, a process that possibly exacerbates ongoing inflammatory and allergic processes.
Characterization of human sialoadhesin, a sialic acid binding receptor expressed by resident and inflammatory macrophage populations
Authors: Hartnell Adele , Steel Jane , Turley Helen , Jones Margaret , Jackson David G. , Crocker Paul R.
Published: July 2002

Sialoadhesin is a macrophage-restricted cellular interaction molecule and a prototypic member of the Siglec family of sialic acid binding immunoglobulin (Ig)-like lectins. So far, it has only been characterized in rodents. Here, we report the molecular cloning, binding properties, and expression pattern of human sialoadhesin. The predicted protein sequences of human and mouse sialoadhesin are about 72% identical, with the greatest similarity in the extracellular region, which comprises 17 Ig domains in both species. A recombinant protein consisting of the first 4 N-terminal domains of human sialoadhesin fused to the Fc region of human IgG1 mediated sialic acid–dependent binding with a specificity similar to its mouse counterpart, preferring sialic acid in the α2,3 glycosidic linkage over the α2,6 linkage. By flow cytometry with peripheral blood leukocytes, recombinant sialoadhesin bound strongly to granulocytes with intermediate binding to monocytes, natural killer cells, B cells, and a subset of CD8 T cells. Using antibodies raised to the recombinant protein, sialoadhesin was immunoprecipitated from the THP-1 human monocytic cell line as an approximate 200-kd glycoprotein. The expression pattern of human sialoadhesin was found to be similar to that of the mouse receptor, being absent from monocytes and other peripheral blood leukocytes, but expressed strongly by tissue macrophages in the spleen, lymph node, bone marrow, liver, colon, and lungs. High expression was also found on inflammatory macrophages present in affected tissues from patients with rheumatoid arthritis.
A randomized comparison between rasburicase and allopurinol in children with lymphoma or leukemia at high risk for tumor lysis
Authors: Goldman Stanton C. , Holcenberg John S. , Finklestein Jerry Z. , Hutchinson Raymond , Kreissman Susan , Johnson F. Leonard , Tou Conrad , Harvey Elizabeth , Morris Erin , Cairo Mitchell S.
Published: July 2002

Standard therapy in the United States for malignancy-associated hyperuricemia consists of hydration, alkalinization, and allopurinol. Urate oxidase catalyzes the enzymatic oxidation of uric acid to a 5 times increased urine soluble product, allantoin. Rasburicase is a new recombinant form of urate oxidase available for clinical evaluation. This multicenter randomized trial compared allopurinol to rasburicase in pediatric patients with leukemia or lymphoma at high risk for tumor lysis. Patients received the assigned uric acid-lowering agent for 5 to 7 days during induction chemotherapy. The primary efficacy end point was to compare the area under the serial plasma uric acid concentration curves during the first 96 hours of therapy (AUC0-96). Fifty-two patients were randomized at 6 sites. In an intent-to-treat analysis, the mean uric acid AUC0-96 was 128 ± 70 mg/dL.hour for the rasburicase group and 329 ± 129 mg/dL.hour for the allopurinol group (P < .0001). The rasburicase versus allopurinol group experienced a 2.6-fold (95% CI: 2.0-3.4) less exposure to uric acid. Four hours after the first dose, patients randomized to rasburicase compared to allopurinol achieved an 86% versus 12% reduction (P < .0001) of initial plasma uric acid levels. No antirasburicase antibodies were detected at day 14. This randomized study demonstrated more rapid control and lower levels of plasma uric acid in patients at high risk for tumor lysis who received rasburicase compared to allopurinol. For pediatric patients with advanced stage lymphoma or high tumor burden leukemia, rasburicase is a safe and effective alternative to allopurinol during initial chemotherapy.
The relative quiescence of hematopoietic stem cells in nonhuman primates
Authors: Mahmud Nadim , Devine Steven M. , Weller Kevin P. , Parmar Simrit , Sturgeon Cord , Nelson Mary C. , Hewett Terry , Hoffman Ronald
Published: July 2002

Quiescence has been thought to be required for the retention of the full biological potential of pluripotent hematopoietic stem cells (PHSCs). This hypothesis has been challenged recently by the observation that all murine PHSCs cycle continuously and constantly contribute to steady-state blood cell production. It was asked whether these observations could be extrapolated to describe hematopoiesis in higher mammals. In this series of experiments, the replicative history of PHSCs was examined in baboons by continuously administering bromodeoxyuridine (BrdU) for more than 85 weeks. The results indicate that under steady-state conditions, PHSCs remain largely quiescent but do cycle, albeit at a far lower rate than previously reported for rodent PHSCs. BrdU-labeled cycling PHSCs and progenitor cells were shown to have an extensive proliferative capacity and to contribute to blood cell production for prolonged periods of time. The proportion of PHSCs entering cell cycle could, however, be rapidly increased by the in vivo administration of granulocyte-colony stimulating factor. These data indicate that during steady-state hematopoiesis, baboon PHSCs require prolonged periods of time to cycle and that the proportion of PHSCs in cycle is not fixed but can be altered by external stimuli. The relative quiescence of PHSCs observed in this nonhuman primate model, in contrast to murine PHSCs, might explain the current barriers to genetic modification and ex vivo expansion of human PHSCs.
Hematopoietic cell transplantation in older patients with hematologic malignancies: replacing high-dose cytotoxic therapy with graft-versus-tumor effects
Authors: McSweeney Peter A. , Niederwieser Dietger , Shizuru Judith A. , Sandmaier Brenda M. , Molina Arthur J. , Maloney David G. , Chauncey Thomas R. , Gooley Theodore A. , Hegenbart Ute , Nash Richard A. , Radich Jerald , Wagner John L. , Minor Steven , Appelbaum Frederick R. , Bensinger William I. , Bryant Eileen , Flowers Mary E. D. , Georges George E. , Grumet F. Carl , Kiem Hans-Peter , Torok-Storb Beverly , Yu Cong , Blume Karl G. , Storb Rainer F.
Published: July 2002

Toxicities have limited the use of allogeneic hematopoietic cell transplantation (HCT) to younger, medically fit patients. In a canine HCT model, a combination of postgrafting mycophenolate mofetil (MMF) and cyclosporine (CSP) allowed stable allogeneic engraftment after minimally toxic conditioning with low-dose (200 cGy) total-body irradiation (TBI). These findings, together with the known antitumor effects of donor leukocyte infusions (DLIs), led to the design of this trial. Forty-five patients (median age 56 years) with hematologic malignancies, HLA-identical sibling donors, and relative contraindications to conventional HCT were treated. Immunosuppression involved TBI of 200 cGy before and CSP/MMF after HCT. DLIs were given after HCT for persistent malignancy, mixed chimerism, or both. Regimen toxicities and myelosuppression were mild, allowing 53% of eligible patients to have entirely outpatient transplantations. Nonfatal graft rejection occurred in 20% of patients. Grades II to III acute graft-versus-host disease (GVHD) occurred in 47% of patients with sustained engraftment. With median follow-up of 417 days, survival was 66.7%, nonrelapse mortality 6.7%, and relapse mortality 26.7%. Fifty-three percent of patients with sustained engraftment were in complete remission, including 8 with molecular remissions. This novel allografting approach, based on the use of postgrafting immunosuppression to control graft rejection and GVHD, has dramatically reduced the acute toxicities of allografting. HCT with the induction of potent graft-versus-tumor effects can be performed in previously ineligible patients, largely in an outpatient setting. Future protocol modifications should reduce rejection and GVHD, thereby facilitating studies of allogeneic immunotherapy for a variety of malignancies.
Chemotaxis and transendothelial migration of CD34+hematopoietic progenitor cells induced by the inflammatory mediator leukotriene D4 are mediated by the 7-transmembrane receptor CysLT1
Authors: Bautz Frank , Denzlinger Claudio , Kanz Lothar , Möhle Robert
Published: July 2002

Recent studies suggest that bone marrow (BM)–derived chemotactic mediators such as chemokines play key roles in hematopoietic stem cell trafficking. Lipid mediators, particularly leukotrienes, are involved in leukocyte chemotaxis during inflammation but have also been detected in the normal BM. Therefore, the effects of leukotrienes on hematopoietic progenitor cells were analyzed. Cysteinyl leukotrienes, particularly leukotriene D4 (LTD4), induced strong intracellular calcium fluxes and actin polymerization in mobilized and BM CD34+ progenitors. Chemotaxis and in vitro transendothelial migration of CD34+ and more primitive CD34+/CD38− cells were 2-fold increased by LTD4 at an optimum concentration of 25 to 50 nM. Accordingly, CD34+ cells expressed the 7-transmembrane LTD4 receptor CysLT1 by reverse transcriptase–polymerase chain reaction and Western blot. Effects of LTD4 were suppressed by the CysLT1 receptor antagonist MK-571 and reduced by pertussis toxin. In contrast, LTB4 induced strong responses only in mature granulocytes. LTD4-induced calcium fluxes were also observed in granulocytes but were not reduced by MK-571, suggesting that these effects were mediated by other receptors (eg, CysLT2) rather than by CysLT1. In addition, expression of 5-lipoxygenase, the key enzyme of leukotriene biosynthesis, was detected in both hematopoietic progenitor cells and mature leukocytes. The study concludes that the functionally active LTD4 receptor CysLT1 is preferentially expressed in immature hematopoietic progenitor cells. LTD4 released in the BM might regulate progenitor cell trafficking and could also act as an autocrine mediator of hematopoiesis. This would be a first physiologic effect of cysteinyl leukotrienes apart from the many known pathophysiologic actions related to allergy and inflammation.
Severe impairment of leukocyte rolling in venules of core 2 glucosaminyltransferase–deficient mice
Authors: Sperandio Markus , Thatte Aravinda , Foy Dan , Ellies Lesley G. , Marth Jamey D. , Ley Klaus
Published: July 2002

Leukocyte capture and rolling are mediated by selectins expressed on leukocytes (L-selectin) and the vascular endothelium (P- and E-selectin). To investigate the role of core 2 β1-6-N-glucosaminyltransferase (C2GlcNAcT-I) for synthesis of functional selectin ligands in vivo, leukocyte rolling flux and velocity were studied in venules of untreated and tumor necrosis factor-α (TNFα)–pretreated autoperfused cremaster muscles of C2GlcNAcT-I–deficient (core 2−/−) and littermate control mice. In untreated core 2−/− mice, leukocyte rolling was dramatically reduced with markedly increased rolling velocities (81 ± 4 μm/s vs 44 ± 3 μm/s). The reduced rolling in core 2−/− mice was due mainly to severely impaired binding of P-selectin to P-selectin glycoprotein ligand-1 (PSGL-1). Some rolling remained after blocking PSGL-1 in controls but not in core 2−/− mice. In TNFα-pretreated mice, rolling was markedly reduced in core 2−/− mice owing to impaired P-selectin– and E-selectin–mediated rolling. Rolling velocities in core 2−/− mice treated with an E-selectin–blocking monoclonal antibody (59 ± 4 μm/s) were significantly higher than in controls (14 ± 1 μm/s), which provides further evidence for the severe impairment in P-selectin–mediated rolling. In conclusion, P-selectin ligands including PSGL-1 are largely C2GlcNAcT-I dependent. In addition, E-selectin–mediated rolling in vivo is partially dependent on the targeted C2GlcNAcT-I.
B-cell development in progressively transformed germinal centers: similarities and differences compared with classical germinal centers and lymphocyte-predominant Hodgkin disease
Authors: Bräuninger Andreas , Yang Wentao , Wacker Hans-Heinrich , Rajewsky Klaus , Küppers Ralf , Hansmann Martin-Leo
Published: July 2002

Progressively transformed germinal centers (PTGCs) are histologic structures mainly composed of small resting B cells and intermingled proliferating centroblast-like cells. The B-cell differentiation processes within PTGCs and their relation to classical germinal centers (GC) and to lymphocyte-predominant Hodgkin disease (LPHD), with which PTGCs are often associated, are largely unknown. To address these issues, single small resting (Ki67−) and proliferating (Ki67+) centroblast-like cells were isolated from 7 PTGCs of 5 lymph nodes, and rearranged immunoglobulin genes were amplified and sequenced. Most small resting B cells were clonally unrelated, and most carried unmutated immunoglobulin gene rearrangements resembling mantle zone B cells. Small resting B cells with mutated immunoglobulin gene rearrangements may represent centrocytes, memory B cells, or both. Among the centroblast-like Ki67+ cells, expanded B-cell clones were observed in 6 of 7 PTGCs analyzed. Clonally related V region genes showed extensive intraclonal diversity, and the mutation pattern indicated stringent selection of the cells for the expression of functional antigen receptors. Thus, somatic hypermutation, clonal expansion, and selection occur also in the disorganized PTGC microenvironment, as in classical GCs. In lymph nodes affected by PTGCs, no clonal expansion across the borders of individual PTGCs was observed, distinguishing PTGCs from LPHD.
V H 1-69 gene is preferentially used by hepatitis C virus–associated B cell lymphomas and by normal B cells responding to the E2 viral antigen
Authors: Chan Chunghuang Hubert , Hadlock Kenneth G. , Foung Steven K. H. , Levy Shoshana
Published: July 2002

Hepatitis C virus (HCV)–associated B cell lymphomas were previously shown to express a restricted repertoire of immunoglobulin VH and VL genes, VH1-69 and VκA27, respectively. Although this suggests a role for antigen selection in the pathogenesis of these lymphomas, the driving antigen involved in the clonal expansion has not been identified. B cell response to a viral antigen, the HCV envelope glycoprotein 2 (E2), was analyzed in an asymptomatic HCV-infected patient. Single B cells, immortalized as hybridomas and selected for binding E2, were analyzed for their V gene usage. Sequences of these V region genes demonstrated that each hybridoma expressed unique VH and VLgenes. Remarkably, these anti-E2 hybridomas preferentially used the VH1-69 gene. Analysis of replacement to silent mutation ratios indicated that the genes underwent somatic mutation and antigenic selection. In a separate report, human anti-E2 antibodies were also shown to express the same VH gene. These data strengthen the hypothesis that the HCV-associated lymphomas are derived from clonally expanded B cells stimulated by HCV.
Platelet-endothelial cell adhesion molecule-1 (PECAM-1)–deficient mice demonstrate a transient and cytokine-specific role for PECAM-1 in leukocyte migration through the perivascular basement membrane
Authors: Thompson Richard D. , Noble Karen E. , Larbi Karen Y. , Dewar Ann , Duncan Gordon S. , Mak Tak W. , Nourshargh Sussan
Published: July 2002

Studies with neutralizing antibodies have indicated roles for platelet-endothelial cell adhesion molecule-1 (PECAM-1) in leukocyte migration through the endothelium and the perivascular basement membrane. Because some of these findings have been contentious, this study aimed to explore the role of PECAM-1 in leukocyte migration by analyzing leukocyte responses in interleukin 1β (IL-1β)– and tumor necrosis factor-α (TNFα)–activated cremasteric venules of PECAM-1–deficient mice using intravital and electron microscopy. Although no differences in levels of leukocyte rolling flux or firm adhesion were observed, a delay in leukocyte transmigration in response to IL-1β, but not TNFα, was detected in PECAM-1–deficient mice. Electron microscopy indicated that this delay occurred at the level of perivascular basement membrane. To address the cytokine specificity of PECAM-1 dependence, in vitro experiments demonstrated that TNFα, but not IL-1β, could induce rapid adhesion of murine neutrophils to protein-coated surfaces, suggesting that TNFα elicited leukocyte transmigration in wild-type mice via direct stimulation of leukocytes. In summary, the results suggest a regulatory role for PECAM-1 in leukocyte migration through the perivascular basement membrane, a role that appears to be cytokine-specific and associated with the ability of the cytokine to stimulate rapid neutrophil adhesion.
Regulation of the PU.1 gene by distal elements
Authors: Li Youlin , Okuno Yutaka , Zhang Pu , Radomska Hanna S. , Chen Hui-min , Iwasaki Hiromi , Akashi Koichi , Klemsz Michael J. , McKercher Scott R. , Maki Richard A. , Tenen Daniel G.
Published: July 2002

The transcription factor PU.1 (also known as Spi-1) plays a critical role in the development of the myeloid lineages, and myeloid cells derived from PU.1−/− animals are blocked at the earliest stage of myeloid differentiation. Expression of the PU.1 gene is tightly regulated during normal hematopoietic development, and dysregulation of PU.1 expression can lead to erythroleukemia. However, relatively little is known about how the PU.1 gene is regulated in vivo. Here it is shown that myeloid cell type–specific expression of PU.1 in stable cell lines and transgenic animals is conferred by a 91-kilobase (kb) murine genomic DNA fragment that consists of the entire PU.1 gene (20 kb) plus approximately 35 kb of upstream and downstream sequences, respectively. To further map the important transcriptional regulatory elements, deoxyribonuclease I hypersensitive site mapping studies revealed at least 3 clusters in the PU.1 gene. A 3.5-kb fragment containing one of these deoxyribonuclease I hypersensitive sites, located −14 kb 5′ of the transcriptional start site, conferred myeloid cell type–specific expression in stably transfected cell lines, suggesting that within this region is an element important for myeloid specific expression of PU.1. Further analysis of this myeloid-specific regulatory element will provide insight into the regulation of this key transcriptional regulator and may be useful as a tool for targeting expression to the myeloid lineage.
Benzene metabolites antagonize etoposide-stabilized cleavable complexes of DNA topoisomerase IIα
Authors: Baker Ronda K. , Kurz Ebba U. , Pyatt David W. , Irons Richard D. , Kroll David J.
Published: July 2002

Chronic exposure to benzene is associated with hematotoxicity and acute myelogenous leukemia. Inhibition of topoisomerase IIα (topo II) has been implicated in the development of benzene-induced cytogenetic aberrations. The purpose of this study was to determine the mechanism of topo II inhibition by benzene metabolites. In a DNA cleavage/relaxation assay, topo II was inhibited byp-benzoquinone and hydroquinone at 10 μM and 10 mM, respectively. On peroxidase activation, inhibition was seen with 4,4′-biphenol, hydroquinone, and catechol at 10 μM, 10 μM, and 30 μM, respectively. But, in no case was cleavable complex stabilization observed and the metabolites appeared to act at an earlier step of the enzyme cycle. In support of this conclusion, several metabolites antagonized etoposide-stabilized cleavable complex formation and inhibited topo II–DNA binding. It is therefore unlikely that benzene-induced acute myelogenous leukemia stems from events invoked for leukemogenic topo II cleavable complex-stabilizing antitumor agents.
Variable protection of β3-integrin–deficient mice from thrombosis initiated by different mechanisms
Authors: Smyth Susan S. , Reis Ernane D. , Väänänen Heikki , Zhang Wen , Coller Barry S.
Published: July 2002

Platelet integrin αIIbβ3 (GPIIb/IIIa) plays a central role in the initiation of arterial thrombosis, but its contribution to disseminated microvascular thrombosis is less well defined. Therefore, wild-type mice (β3+/+), β3-integrin–deficient mice (β3−/−), and wild-type mice treated with a hamster monoclonal antibody (1B5) that blocks murine αIIbβ3 function were tested in models of large-vessel and microvascular thrombosis. In the large-vessel model, ferric chloride was used to injure the carotid artery, and the time to thrombosis was measured. In β3+/+mice, the median time to occlusion was 6.7 minutes, whereas occlusion did not occur in any of the β3−/− mice tested (P < .001). Fab and F(ab')2 fragments of 1B5 increased the median time to occlusion. To initiate systemic intravascular thrombosis, prothrombotic agents were administered intravenously, and platelet thrombus formation was monitored by the decrease in circulating platelet count. Three minutes after the injection of adenosine diphosphate (ADP), collagen + epinephrine, or tissue factor, the platelet counts in β3+/+ mice decreased by 289, 424, and 429 × 103/μL, respectively. β3−/− mice and wild-type mice pretreated with 1B5 Fab (1 mg/kg, IP) were nearly completely protected from the effects of ADP. In contrast, β3−/− mice were only partially protected from the effects of collagen + epinephrine and minimally protected from the effects of tissue factor. In all cases, less fibrin became deposited in the lungs of β3−/− mice than in wild-type mice. These results suggest that though αIIbβ3 plays a dominant role in large-vessel thrombosis, it plays a variable role in systemic intravascular thrombosis.
Therapeutic efficacy of intravenous immunoglobulin preparations depends on the immunoglobulin G dimers: studies in experimental immune thrombocytopenia
Authors: Teeling Jessica L. , Jansen-Hendriks Theo , Kuijpers Taco W. , de Haas Masja , van de Winkel Jan G. J. , Hack C. Erik , Bleeker Wim K.
Published: July 2002

The clinical benefit of intravenous immunoglobulin (IVIG) preparations in the treatment of immune thrombocytopenic purpura (ITP) is supposed to be mediated by blockade of Fcγ receptor–bearing phagocytes. In 2 experimental models for ITP, it is shown that the therapeutic efficacy of IVIG preparations is related to the IgG dimer content present in these preparations. A rat monoclonal antibody (mAb; MWReg30) directed to the murine platelet-specific integrin αIIbβ3 (gpIIb/IIIa) was administered intraperitoneally either as bolus injection or continuous infusion. With bolus injection, the circulating platelet count dropped to almost zero within 3 hours. Pretreatment with cobra venom factor did not affect platelet depletion, whereas pretreatment with anti-FcγRII/III mAb 2.4G2 or IVIG greatly reduced platelet clearance. With continuous infusion, platelet numbers reached a steady state after 4 days, at approximately 25% of control. This reduction in platelets was, however, not observed in mice deficient for the FcRγ-chain, lacking FcγRI, FcγRIII, and FcγRIII−/− mice. Infusion of a single dose of IVIG with a high IgG dimer content on the 4th day—ie, mimicking therapeutic administration—resulted in a platelet increase for several days. IVIG predominantly consisting of monomeric IgG had no effect on platelet numbers. In conclusion, continuous infusion of MWReg30 induces thrombocytopenia in mice by enhancing Fcγ receptor–mediated clearance of platelets. In this model, it is shown that IgG dimers present in IVIG preparations are responsible for the increase in platelet counts.
Multidrug-resistance phenotype and clinical responses to gemtuzumab ozogamicin
Authors: Linenberger Michael L. , Hong Tom , Flowers David , Sievers Eric L. , Gooley Ted A. , Bennett John M. , Berger Mark S. , Leopold Lance H. , Appelbaum Frederick R. , Bernstein Irwin D.
Published: July 2002

Expression of multidrug resistance (MDR) features by acute myeloid leukemia (AML) cells predicts a poor response to many treatments. The MDR phenotype often correlates with expression of P-glycoprotein (Pgp), and Pgp antagonists such as cyclosporine (CSA) have been used as chemosensitizing agents in AML. Gemtuzumab ozogamicin, an immunoconjugate of an anti-CD33 antibody linked to calicheamicin, is effective monotherapy for CD33+ relapsed AML. However, the contribution of Pgp to gemtuzumab ozogamicin resistance is poorly defined. In this study, blast cell samples from relapsed AML patients eligible for gemtuzumab ozogamicin clinical trials were assayed for Pgp surface expression and Pgp function using a dye efflux assay. In most cases, surface expression of Pgp correlated with Pgp function, as indicated by elevated dye efflux that was inhibited by CSA. Among samples from patients who either failed to clear marrow blasts or failed to achieve remission, 72% or 52%, respectively, exhibited CSA-sensitive dye efflux compared with 29% (P = .003) or 24% (P < .001) among samples from responders. In vitro gemtuzumab ozogamicin–induced apoptosis was also evaluated using an annexin V–based assay. Low levels of drug-induced apoptosis were associated with CSA-sensitive dye efflux, whereas higher levels correlated strongly with achievement of remission and marrow blast clearance. In vitro drug-induced apoptosis could be increased by CSA in 14 (29%) of 49 samples exhibiting low apoptosis in the absence of CSA. Together, these findings indicate that Pgp plays a role in clinical resistance to gemtuzumab ozogamicin and suggest that treatment trials combining gemtuzumab ozogamicin with MDR reversal agents are warranted.
Regulation of P-selectin binding to the neutrophil P-selectin counter-receptor P-selectin glycoprotein ligand-1 by neutrophil elastase and cathepsin G
Authors: Gardiner Elizabeth E. , De Luca Mariagrazia , McNally Tracy , Michelson Alan D. , Andrews Robert K. , Berndt Michael C.
Published: July 2002

In the inflammatory response, leukocyte rolling before adhesion and transmigration through the blood vessel wall is mediated by specific cell surface adhesion receptors. Neutrophil rolling involves the interaction of P-selectin expressed on activated endothelium and its counter-receptor on neutrophils, P-selectin glycoprotein ligand-1 (PSGL-1). Here, it is reported that P-selectin binding to neutrophils is lost under conditions that cause the release of proteinases from neutrophil primary granules. Treatment of neutrophils with the purified neutrophil granule proteinases, cathepsin G and elastase, rapidly abolished their capacity to bind P-selectin. This inactivation corresponded to loss of the N-terminal domain of PSGL-1, as assessed by Western blot analysis. A loss of intact PSGL-1 protein from the surfaces of neutrophils after the induction of degranulation was also detected by Western blot analysis. Cathepsin G initially cleaved near the PSGL-1 N-terminus, whereas neutrophil elastase predominantly cleaved at a more C-terminal site within the protein mucin core. Consistent with this, cathepsin G cleaved a synthetic peptide based on the PSGL-1 N-terminus between Tyr-7/Leu-8. Under conditions producing neutrophil degranulation in incubations containing mixtures of platelets and neutrophils, the loss of PSGL-1, but not P-selectin, from platelet-neutrophil lysates was detected. Cathepsin G- or neutrophil elastase-mediated PSGL-1 proteolysis may constitute a potential autocrine mechanism for down-regulation of neutrophil adhesion to P-selectin.
Immunophenotypic profiles in families with autoimmune lymphoproliferative syndrome
Authors: Bleesing Jack J. H. , Brown Margaret R. , Straus Stephen E. , Dale Janet K. , Siegel Richard M. , Johnson Michele , Lenardo Michael J. , Puck Jennifer M. , Fleisher Thomas A.
Published: July 2002

Autoimmune lymphoproliferative syndrome (ALPS) type Ia is caused by inherited defects in apoptosis and is characterized by nonmalignant lymphoaccumulation, autoimmunity, and increased α/β+ double-negative T cells (α/β+-DNT cells). This study reports immunophenotypic findings in 166 members of 31 families with ALPS type Ia, associated with genetic mutations in theTNFRSF6 gene encoding Fas. The ALPS type Ia probands (n = 31) and relatives having both a Fas mutation and clinically proven ALPS (n = 28) showed significant expansion of CD8+T cells, α/β+-DNT cells, γ/δ+-DNT cells, CD3+/ HLA-DR+ T cells, CD8+/CD57+ T cells, and CD5+ B cells. Relatives with Fas mutations, but without all the required criteria for ALPS (n = 42), had expansions of CD8+ T cells, α/β+-DNT cells, and γ/δ+-DNT cells. Interestingly, relatives without a Fas mutation and with no features of ALPS (n = 65) demonstrated a small but significant expansion of CD8+ T cells, both DNT cell subsets, and CD5+ B cells. As compared to unrelated healthy controls, lymphocyte subset alterations were greatest in the probands, followed by the relatives with mutations and ALPS. Probands and relatives with mutations and ALPS also showed a lower number of CD4+/CD25+ T cells that, in combination with an independent increase in HLA-DR+ T cells, provided a profile predictive of the presence of clinical ALPS. Because quantitative defects in apoptosis were similar in mutation-positive relatives regardless of the presence of clinical ALPS, factors, other than modifiers of the Fas apoptosis pathway, leading to these distinctive immunophenotypic profiles most likely contribute to disease penetrance in ALPS.
Characterization of human cytomegalovirus peptide–specific CD8+ T-cell repertoire diversity following in vitro restimulation by antigen-pulsed dendritic cells
Authors: Peggs Karl , Verfuerth Stephanie , Pizzey Arnold , Ainsworth Jenni , Moss Paul , Mackinnon Stephen
Published: July 2002

Under conditions of impaired T-cell immunity, human cytomegalovirus (HCMV) can reactivate from lifelong latency, resulting in potentially fatal disease. A crucial role for CD8+ T cells has been demonstrated in control of viral replication, and high levels of HCMV-specific cytotoxic T-lymphocytes are seen in immunocompetent HCMV-seropositive individuals despite very low viral loads. Elucidation of the minimum portion of the anti-HCMV T-cell repertoire that is required to suppress viral replication requires further study of clonal composition. The ability of dendritic cells to take up and process exogenous viral antigen by constitutive macropinocytosis was used to study HCMV-specific T-cell memory in the absence of viral replication. The specificity and clonal composition of the CD8+ T-cell responses were evaluated using HLA tetrameric complexes and T-cell receptor β chain (TCRBV) spectratypic analyses. There was a skewed reactivity toward the matrix protein pp65, with up to 40-fold expansion of CD8+ T cells directed toward a single peptide-MHC combination. Individual expansions detected on TCRBV spectratype analysis were HCMV-specific and composed of single or highly restricted numbers of clones. There was preferential TCRBV gene usage (BV6.1/6.2, BV8, and BV13 in HLA-A*0201+ individuals) but lack of conservation of CDR3 length and junctional motifs between donors. While there was a spectrum of TCR repertoire diversity directed toward individual MHC-peptide combinations between donors, a relatively small number of clones appeared to predominate the response in each case. These data provide further insight into the range of anti-HCMV responses and will aid the design and monitoring of adoptive immunotherapy protocols.
Interleukin-10 modulates the sensitivity of peritoneal B lymphocytes to chemokines with opposite effects on stromal cell–derived factor-1 and B-lymphocyte chemoattractant
Authors: Balabanian Karl , Foussat Arnaud , Bouchet-Delbos Laurence , Couderc Jacques , Krzysiek Roman , Amara Ali , Baleux Françoise , Portier Alain , Galanaud Pierre , Emilie Dominique
Published: July 2002

Interleukin-10 (IL-10) is constitutively produced by peritoneal B1a lymphocytes, and stromal cell–derived factor-1 (SDF-1) by mesothelial cells. Independent studies have shown that both IL-10 and SDF-1 are involved in the persistence of the peritoneal B-lymphocyte compartment. This study shows that IL-10 and SDF-1 act in synergy on peritoneal B lymphocytes. Indeed, autocrine production of IL-10 was absolutely required for all effects of SDF-1 on these cells, including increased proliferation, survival, and chemotaxis. Moreover, adding IL-10 to peritoneal B lymphocytes increased the effects of SDF-1. Neither IL-5, IL-6, nor IL-9 affected the response of peritoneal B lymphocytes to SDF-1. IL-10 was chemokinetic for peritoneal B lymphocytes, increasing their random mobility. It also potentiated the SDF-1–induced reorganization of the cytoskeleton without affecting CXCR4 gene expression by peritoneal B lymphocytes. Despite its chemokinetic properties, IL-10 abolished the migration of peritoneal B lymphocytes in response to B-lymphocyte chemoattractant (BLC), a chemokine targeting B lymphocytes to lymphoid organ follicles. The ability of B1a lymphocytes to produce IL-10 constitutively, combined with the opposite effects of this cytokine on the responses to SDF-1 and BLC, may account for the selective accumulation of B1 lymphocytes in body cavities.
Multiple hematopoietic cell lineages develop in vivo from transplanted Pax5-deficient pre-B I–cell clones
Authors: Schaniel Christoph , Bruno Ludovica , Melchers Fritz , Rolink Antonius G.
Published: July 2002

Pax5-deficient pre-B I–cell clones, transplanted into natural killer (NK)–cell–deficient RAG2−/−IL-2Rγ−/−hosts, populate the NK-cell compartment with functional NK cells. NK-cell generation fromPax5−/−pre-B I cells is also observed in NK-cell–proficient Balb/c RAG2−/− hosts. In the same Balb/c RAG2−/− hosts,Pax5−/− pre-B I–cell clones not only populate the pre-B I–cell compartment and fill the deficient T-cell–lineage compartment in the thymus and the periphery of all hosts, as shown before, they also generate CD8α− and CD8α+ dendritic cells (DCs), macrophages, and granulocytes in vivo in approximately half the hosts. In some recipients, practically all the mature myeloid cells are ofPax5−/− origin, indicating the effectiveness by which Pax5−/−pre-B I cells can compete with endogenous myeloid precursors. In a smaller percentage of hosts, the generation of Pax5−/−pre-B I–cell–derived erythrocytes is observed 4 to 6 months after transplantation. The results indicate that Pax5−/−pre-B I cells can develop in vivo in hosts that have undergone transplantation to erythroid, myeloid, and lymphoid cell lineages. Hence, the Pax5−/−mutation introduces an unusual instability of differentiation in pre-B I cells so that they appear to dedifferentiate as far back as the pluripotent hematopoietic stem cell.
P-glycoprotein–actin association through ERM family proteins: a role in P-glycoprotein function in human cells of lymphoid origin
Authors: Luciani Francesca , Molinari Agnese , Lozupone Francesco , Calcabrini Annarica , Lugini Luana , Stringaro Annarita , Puddu Patrizia , Arancia Giuseppe , Cianfriglia Maurizio , Fais Stefano
Published: July 2002

P-glycoprotein is a 170-kd glycosylated transmembrane protein, expressed in a variety of human cells and belonging to the adenosine triphosphate–binding cassette transporter family, whose membrane expression is functionally associated with the multidrug resistance phenotype. However, the mechanisms underlying the regulation of P-glycoprotein functions remain unclear. On the basis of some evidence suggesting P-glycoprotein–actin cytoskeleton interaction, this study investigated the association of P-glycoprotein with ezrin, radixin, and moesin, a class of proteins that cross-link actin filaments with plasma membrane in a human cell line of lymphoid origin and that have been shown to link other ion-pump–related proteins. To this purpose, a multidrug-resistant variant of CCRF-CEM cells (CEM-VBL100) was used as a model to investigate the following: (1) the cellular localizations of P-glycoprotein and ezrin, radixin, and moesin and their molecular associations; and (2) the effects of ezrin, radixin, and moesin antisense oligonucleotides on multidrug resistance and P-glycoprotein function. The results showed that: (1) P-glycoprotein colocalized and coimmunoprecipitated with ezrin, radixin, and moesin; and (2) treatment with antisense oligonucleotides for ezrin, radixin, and moesin restored drug susceptibility consistently with inhibition of both drug efflux and actin–P-glycoprotein association and induction of cellular redistribution of P-glycoprotein. These data suggest that P-glycoprotein association with the actin cytoskeleton through ezrin, radixin, and moesin is key in conferring to human lymphoid cells a multidrug resistance phenotype. Strategies aimed at inhibiting P-glycoprotein–actin association may be helpful in increasing the efficiency of both antitumor and antiviral therapies.
Analysis of the IgVH somatic mutations in splenic marginal zone lymphoma defines a group of unmutated cases with frequent 7q deletion and adverse clinical course
Authors: Algara Patricia , Mateo Marisol S. , Sanchez-Beato Margarita , Mollejo Manuela , Navas Immaculada C. , Romero Lourdes , Solé Francesc , Salido Marta , Florensa Lourdes , Martı́nez Pedro , Campo Elias , Piris Miguel A.
Published: July 2002

This study aimed to correlate the frequency of somatic mutations in the IgVH gene and the use of specific segments in the VH repertoire with the clinical and characteristic features of a series of 35 cases of splenic marginal zone lymphoma (SMZL). The cases were studied by seminested polymerase chain reaction by using primers from the FR1 and JH region. The results showed unexpected molecular heterogeneity in this entity, with 49% unmutated cases (less than 2% somatic mutations). The 7q31 deletions and a shorter overall survival were more frequent in this group. Additionally a high percentage (18 of 40 sequences) of SMZL cases showed usage of the VH1-2 segment, thereby emphasizing the singularity of this neoplasia, suggesting that this tumor derives from a highly selected B-cell population and encouraging the search for specific antigens that are pathogenically relevant in the genesis or progression of this tumor.
Flt3 ligand therapy for recipients of allogeneic bone marrow transplants expands host CD8α+ dendritic cells and reduces experimental acute graft-versus-host disease
Authors: Teshima Takanori , Reddy Pavan , Lowler Kathleen P. , KuKuruga Mark A. , Liu Chen , Cooke Kenneth R. , Ferrara James L. M.
Published: July 2002

Recent evidence suggests that dendritic cells (DCs) can regulate and amplify immune responses. Flt3 ligand (FL)–derived DC function was tested as a stimulator of allogeneic lymphocytes in vitro and in vivo. Treatment of mice with FL dramatically expanded DC number, but DCs isolated from FL-treated mice (FL DCs) were poor stimulators of allogeneic T-cell responses in vitro. Further activation of FL DCs did not restore their stimulatory ability, and FL DCs did not suppress the stimulation of the allogeneic T cells by normal DCs. FL treatment significantly increased the CD8α+ DC subset, which appeared to be the reason for their poor stimulatory capacity. These observations were confirmed in vivo using a mouse model of acute graft-versus-host disease (GVHD) wherein host DCs play a critical role. FL treatment of recipients before allogeneic bone marrow transplantation dramatically suppressed donor T-cell responses to host antigens, thereby reducing GVHD mortality (P < .01). These data represent a novel strategy that alters host DCs and reduces acute GVHD.
Tumor Microvessel Density as a Predictor of Recurrence After Resection of Hepatocellular Carcinoma: A Prospective Study
Authors: Poon Ronnie Tung-Ping , Ng Irene Oi-Lin , Lau Cecilia , Yu Wun-Ching , Yang Zhen-Fan , Fan Sheung-Tat , Wong John
Published: July 2002

PURPOSE: This study prospectively evaluated the correlation of tumor microvessel density (MVD) with clinicopathologic features and postoperative recurrence in patients undergoing resection of hepatocellular carcinoma (HCC).

PATIENTS AND METHODS: Tumor MVD was assessed in 100 patients with resection of HCC using a computer image analyzer after immunostaining for CD34 (MVD-CD34) and von Willebrand factor (MVD-vWF), respectively. Patients were prospectively followed for recurrence.

RESULTS: Mean tumor MVD-CD34 (236/0.74 mm2) was higher than mean tumor MVD-vWF (87/0.74 mm2) (P < .001). By multiple regression analysis, tumor size was the only pathologic feature significantly related to tumor MVD-CD34. The median MVD-CD34 was 316/0.74 mm2in HCCs ≤ 5 cm (n = 46) and 146/0.74 mm2in HCCs more than 5 cm (n = 54) (P < .001). Among patients with HCCs ≤ 5 cm, those with higher than median MVD-CD34 had worse disease-free survival (at 3 years, 13%) than those with a lower MVD-CD34 (at 3 year, 74%) (P = .002). Multivariate analysis showed that tumor MVD-CD34 was the only significant factor predictive of disease-free survival in patients with HCC ≤ 5 cm. For HCCs more than 5 cm, MVD-CD34 did not have a significant prognostic influence. MVD-vWF did not have a significant prognostic influence on disease-free survival in either HCCs ≤ 5 cm or more than 5 cm.

CONCLUSION: This study shows that a high MVD-CD34 was predictive of early postresection recurrence in patients with HCCs ≤ 5 cm and, therefore, may be a novel prognostic marker in this subset of patients.
Minimal Residual Disease in Gastric Cancer: Evidence of an Independent Prognostic Relevance of Urokinase Receptor Expression by Disseminated Tumor Cells in the Bone Marrow
Authors: Heiss Markus Maria , Simon Erich H. , Beyer Bianca C.M. , Gruetzner Klaus Uwe , Tarabichi Anwar , Babic Rudolf , Schildberg Friedrich Wilhelm , Allgayer Heike
Published: July 2002

PURPOSE: To study the invasion-related molecule urokinase-type plasminogen activator receptor (u-PAR) expressed by disseminated tumor cells as a biologic predictor of poor survival in a large prospective series of patients with gastric cancer.

PATIENTS AND METHODS: In 156 gastric cancer patients (prospective series), disseminated tumor cells in the bone marrow and the u-PAR expressed by these tumor cells were determined by cytokeratin (CK) 18 immunocytochemistry and u-PAR/CK18 double immunocytochemistry.

RESULTS: In contrast to the mere detection of disseminated tumor cells at primary surgery, the additional evidence of u-PAR on these cells correlated significantly with pathologic T stage (P = .0474) and the expression of u-PAR (P = .0093) and plasminogen-activator inhibitor 1 (P = .0145) in the primary tumor (immunohistochemistry, χ2). Kaplan-Meier analysis revealed no association with prognosis for the mere detection of disseminated tumor cells. In contrast, a significant association was seen between detection of u-PAR on these cells and shorter disease-free (P < .0001) and overall survival (P < .0001). Multivariate analysis revealed that u-PAR on disseminated tumor cells at the time of primary surgery is an independent prognostic factor for disease-free (95% confidence interval [CI], 1.72 to 3.21; P = .024) and overall survival (P = .0049; relative risk, 2.89; 95% CI, 1.92 to 4.30).

CONCLUSION: This is the first large study to show that u-PAR, detected on disseminated tumor cells in the bone marrow, is an independent prognostic parameter in gastric cancer, in contrast to the mere detection of minimal residual disease (MRD). u-PAR may be a promising marker to define a critical subpopulation of disseminated tumor cells and a target to eliminate MRD. Molecular phenotyping of MRD is critical for defining its individual clinical relevance.
Pharmacy Accessibility and Social Vulnerability
Authors: Catalano Giovanni , Khan Muhammad Muntazir Mehdi , Chatzipanagiotou Odysseas P. , Pawlik Timothy M.
Published: August 2024

This cross-sectional study examines the association of availability of primary care practitioners and level of socioeconomic vulnerability with risk of pharmacy deserts in regions of the US.
Dual‐Functional Self‐Assembled Molecule Enabling High‐Performance Deep‐Blue Perovskite Light‐Emitting Diodes
Authors: Li Nan , Xia Yu , Lou Yan‐Hui , Li Yu‐Han , Jin Run‐Jun , He Xiao‐Ying , Chen Chun‐Hao , Chen Jing , Wang Kai‐Li , Wang Zhao‐Kui
Published: August 2024

Great efforts have been made to improve the composition and structure of perovskite light‐emitting diodes (PeLEDs) through methods such as dimensional reduction or halide engineering, thereby reducing non‐radiative recombination. However, deep‐blue PeLEDs still face a deep valence band issue. The mismatched energy level alignment between the perovskite and the hole transport layer (HTL) leads to charge accumulation, resulting in imbalanced carrier transport and injection. Herein, to address the issues of imbalanced carrier injection and defect states in PeLEDs, a deep‐blue perovskite emitter using [4‐(3,6‐Dimethyl‐9H‐carbazol‐9‐yl)butyl]phosphonic acid (Me‐4PACz) as the material to promote hole transport and passivate defects is presented. The stepwise energy level structure design can effectively reduce the hole injection barrier and improve the carrier injection efficiency. Additionally, the electron‐rich P═O bond can effectively passivate the unsaturated Pb2+ in perovskite, reducing non‐radiative recombination caused by defects. Ultimately, stable deep‐blue PeLEDs (≈458 nm) are successfully fabricated with an external quantum efficiency (EQE) of 4.33%. This study provides new insights into the application of self‐assembled monolayers (SAMs) in PeLEDs.