bluuebunny/crossref_metadata_2025 huggingface dataset:
A Factor V Genetic Component Differing From Factor V R506Q Contributes to the Activated Protein C Resistance Phenotype
Authors: Bernardi F. , Faioni E.M. , Castoldi E. , Lunghi B. , Castaman G. , Sacchi E. , Mannucci P.M.
Published: October 2019

Factor V gene polymorphisms were investigated to detect components that may contribute to the activated protein C (APC) resistance phenotype in patients with venous thromboembolism. A specific factor V gene haplotype (HR2) was defined by six polymorphisms and its frequency was found to be similar in normal subjects coming from Italy (0.08), India (0.1), and Somalia (0.08), indicating that it was originated by ancestral mutational events. The relationship between the distribution of normalized APC ratios obtained with the functional assay and haplotype frequency was analyzed in patients heterozygous for factor V R506Q (factor V Leiden). The HR2 haplotype was significantly more frequent in patients with ratios below the 15th percentile than in those with higher ratios or in normal controls. Moreover, the study of 10 patients with APC resistance in the absence of the factor V R506Q mutation showed a 50-fold higher frequency of HR2 homozygotes. The HR2 haplotype was associated with significantly lower APC ratios both in patients with venous thromboembolism and in age- and sex-matched controls. However, the two groups showed similar HR2 haplotype frequencies. Plasma mixing experiments showed that an artificially created double heterozygote for the factor V R506Q mutation and the HR2 haplotype had an APC ratio lower than that expected for a simple R506Q heterozygote. Time-course experiments evaluating the decay of factor V in plasma showed the normal stability of the molecule encoded by the factor V gene marked by the HR2 haplotype, which ruled out the presence of a pseudo-homozygous APC resistance mechanism. Our results provide new insights into the presence of factor V genetic components other than the factor V R506Q that are able to contribute to the APC resistance phenotype in patients with venous thromboembolism.
Expression of the Neural Cell Adhesion Molecule CD56 Is Associated With Short Remission Duration and Survival in Acute Myeloid Leukemia With t(8; 21)(q22; q22)
Authors: Baer Maria R. , Stewart Carleton C. , Lawrence David , Arthur Diane C. , Byrd John C. , Davey Frederick R. , Schiffer Charles A. , Bloomfield Clara D.
Published: October 2019

Although acute myeloid leukemia (AML) with t(8; 21) (q22; q22) is associated with a high complete remission (CR) rate and prolonged disease-free survival, treatment outcome is not universally favorable. Identifying factors that predict for treatment outcome might allow therapy to be optimized based on risk. AML with t(8; 21) has a distinctive immunophenotype, characterized by expression of the myeloid and stem cell antigens CD13, CD15, CD34, and HLADr, and frequent expression of the B-cell antigen CD19 and the neural cell adhesion molecule CD56, a natural killer cell/stem cell antigen. Because CD56 expression has been associated with both extramedullary leukemia and multidrug resistance, we sought to correlate CD56 expression with treatment outcome in AML with t(8; 21). Pretreatment leukemia cells from 29 adult de novo AML patients with t(8; 21) treated on Cancer and Leukemia Group B (CALGB) protocols were immunophenotyped by multiparameter flow cytometry as part of a prospective immunophenotyping study of adult AML (CALGB 8361). CD56 was expressed in 16 cases (55%). There was no correlation between CD56 expression and age, sex, white blood cell count, granulocyte count, the presence of additional cytogenetic abnormalities, or the presence of extramedullary disease at diagnosis. The CR rate to standard-dose cytarabine and daunorubicin was similar for cases with and without CD56 expression (88% v 92%; P = 1.0). Post-CR therapy included at least one course of high-dose cytarabine in 24 of 26 patients who achieved CR; numbers of courses administered were similar in cases with and without CD56 expression. Although post-CR therapy did not differ, CR duration was significantly shorter in cases with CD56 expression compared with those without (median, 8.7 months v not reached; P = .01), as was survival (median, 16.5 months v not reached; P = .008). We conclude that CD56 expression in AML with t(8; 21) is associated with significantly shorter CR duration and survival. Our results suggest that CD56 expression may be useful in stratifying therapy for this subtype of AML.
Skewed X-Inactivation in Carriers of X-Linked Dyskeratosis Congenita
Authors: Vulliamy T.J. , Knight S.W. , Dokal I. , Mason P.J.
Published: October 2019

A gene causing Dyskeratosis Congenita (DC), a rare genetic disorder associated with bone marrow failure, has been mapped to chromosome Xq28, but autosomal inheritance of the disease has also been reported. We have investigated the pattern of X-inactivation in the peripheral blood of carriers of DC using the methylation-sensitive Hpa II site in the androgen receptor gene (HUMARA). In 5 different families in which the inheritance of DC appears to be X-linked, all 16 carriers showed skewed X-inactivation patterns. These cases indicate that, in the hematopoiesis of heterozygous females, cells expressing the normal DC allele have a growth advantage over cells that express the mutant allele. In 7 other families with sporadic cases of DC or with an uncertain pattern of inheritance, both skewed and normal patterns of X-inactivation were observed. In these families or where crucial family members are unavailable, the study of X-inactivation patterns will add to linkage analysis in providing information about carrier status.
Clonal Variability in β-Globin mRNA Content in an Interleukin-3–Dependent Bone Marrow Cell Line Transfected With the Erythropoietin Receptor Before and After Stimulation With Erythropoietin
Authors: Ishiguro Kimiko , Sartorelli Alan C.
Published: October 2019

Unexpected clonal variability was observed in the content of β-globin mRNA in erythropoietin receptor (EpoR)-transfected Ba/F3 cells before and after exposure to erythropoietin (Epo). Of 11 clones selected by virtue of G418 resistance and positive EpoR expression, 5 clones showed high levels of βmajor-globin mRNA before Epo exposure, with subsequent Epo treatment causing little or no increase in globin mRNA. Five clones had undetectable levels of globin mRNA before Epo stimulation, and they did not accumulate globin mRNA when exposed to Epo, exhibiting resistance to the differentiation inducing action of Epo. Only one clone exhibited the expected phenotype, a low level of globin mRNA before exposure to Epo, and a significant Epo-dependent accumulation of globin mRNA. Phosphorylation of tyrosyl residues of the EpoR, Stat5, and JAK2 occurred upon Epo stimulation in clones representing each category. Furthermore, electrophoretic mobility shift assays using a Stat5 consensus sequence showed a difference in the nuclear binding component among these clones. These findings indicate that (1) the attainment of EpoR+ Ba/F3 clones with the anticipated sensitivity to both the growth and differentiation inducing actions of Epo is a rare event and (2) STAT5 transcription factors were differently activated by Epo in clones that differed in sensitivity to Epo.
Relative Importance of the Glycoprotein Ib-Binding Domain and the RGD Sequence of von Willebrand Factor for Its Interaction With Endothelial Cells
Authors: Perrault Christelle , Lankhof Hanneke , Pidard Dominique , Kerbiriou-Nabias Danièle , Sixma Jan J. , Meyer Dominique , Baruch Dominique
Published: October 2019

Endothelial cell adhesion to von Willebrand Factor is mainly mediated through an interaction between the αvβ3 integrin and the RGD sequence of von Willebrand factor (vWF ). To define the potential involvement of glycoprotein Ibα (GPIbα) as an endothelial vWF receptor, we compared cell adhesion to three recombinant vWF, the wild-type (WT-rvWF ) and two mutants, RGGS-rvWF (D1746G), defective for binding to platelet αIIbβ3, and ΔA1-rvWF with a deletion between amino-acids 478 and 716, which does not bind to platelet GPIbα. Adhesion of human umbilical vein endothelial cells to purified vWF recombinants was measured by automatized cell counting using an image analyzer. Whereas cell adhesion to ΔA1-rvWF was unchanged compared with WT-rvWF, reaching a plateau of 40% total cells at a concentration of 2.5 μg/mL rvWF, adhesion to RGGS-rvWF was only 10% of total cells. Cell stimulation by tumor necrosis factor-α (TNFα), reported to upregulate the expression of the putative endothelial GPIbα, did not modify adhesion to these rvWF. Monoclonal antibodies to vWF or GPIbα, blocking vWF interaction with platelet GPIbα, were unable to inhibit endothelial cell adhesion to rvWF. In contrast, antibody 9 to vWF, blocking the αvβ3-dependent endothelial cell adhesion to plasma vWF, inhibited adhesion to WT-rvWF as efficiently as to ΔA1-rvWF (50% inhibition at a concentration of 11 and 15 μg/mL, respectively). In agreement with the fact that endothelial cell adhesion to vWF appeared independent of the GPIbα-binding domain, we were unable to detect endothelial surface expression of GPIbα by flow cytometry or in cell lysates by immunoprecipitation followed by immunoblotting. Moreover, expression of GPIbα mRNA was undetectable in endothelial cells, even after stimulation by TNFα. These studies indicate that GPIbα is not expressed in human cultured endothelial cells and is not involved in adhesion to vWF-containing surfaces. Thus, in static conditions, cultured endothelial cells adhere to vWF through an αvβ3-dependent, GPIbα-independent mechanism.
Dilazep, an Antiplatelet Agent, Inhibits Tissue Factor Expression in Endothelial Cells and Monocytes
Authors: Deguchi Hiroshi , Takeya Hiroyuki , Wada Hideo , Gabazza Esteban C. , Hayashi Nobuyuki , Urano Hajime , Suzuki Koji
Published: October 2019

Dilazep, an antiplatelet agent, is generally used as an antithrombotic drug in clinical practice. Dilazep is also known to exert cytoprotective and antioxidant effects on endothelial cells. However, its effect on the endothelial or monocyte procoagulant activity is unknown. In the current study, the effect of dilazep on the expression of tissue factor (TF ) in human umbilical vein endothelial cells (HUVECs) after the stimulation with tumor necrosis factor-α (TNF ), thrombin, or phorbol 12-myristate 13-acetate (PMA) was evaluated. We also evaluated the effect of dilazep on TNF (1,000 U/mL)-induced TF expression on monocytes. Dilazep inhibited TF activity induced on HUVECs by each stimulant, TNF (1000 U/mL), thrombin (25 nmol/L), or PMA (5 nmol/L) in a dose-dependent fashion (1 to 100 μg/mL). TF activity decreased to approximately 10% after treating with 100 μg/mL of dilazep. Dilazep also blocked the expression of TF antigen induced by each stimulant on the surface of HUVECs as determined by flow cytometric analysis. In addition, in HUVECs, it significantly decreased the expression of TF mRNA and the total TF antigen induced by thrombin or PMA, but not those induced by TNF, suggesting that dilazep blocks the TF expression induced by PMA or thrombin at a transcriptional level and that induced by TNF at a posttranscriptional level. Western blot analysis showed that dilazep reduces the accumulation of native TF but increases that in lower molecular weight TF derivatives. The adenosine receptor antagonist, 8-(p-sulfophenyl) theophylline, partially counteracted the anticoagulant activity of dilazep on HUVECs, thereby suggesting that the inhibitory effect of dilazep on TF expression in HUVECs depends, at least in part, on its adenosine potentiating activity. Dilazep also inhibited TNF-induced TF expression on monocytes in a dose-dependent fashion (0.1 to 100 μg/mL). In brief, the current study showed for the first time that dilazep, a commonly used antiplatelet drug, strongly inhibits the TF expression in HUVECs and monocytes. Dilazep may have a potent therapeutic value in patients with hypercoagulable state for its inhibitory property on the procoagulant activity of endothelial cells and monocytes.
New Xenograft Model of Multiple Myeloma and Efficacy of a Humanized Antibody Against Human Interleukin-6 Receptor
Authors: Tsunenari Toshiaki , Koishihara Yasuo , Nakamura Akito , Moriya Miki , Ohkawa Hiroyuki , Goto Hideo , Shimazaki Chihiro , Nakagawa Masao , Ohsugi Yoshiyuki , Kishimoto Tadamitsu , Akamatsu Ken-ichi
Published: October 2019

A new xenograft model of multiple myeloma (MM), where growth is strongly regulated by interleukin-6 (IL-6), was established in severe combined immunodeficiency (SCID) mice. In this model, endogenous IL-6 from SCID mice was ineffective at eliciting growth of the established human MM cell line KPMM2; these cells achieved autonomous growth through their autocrine secretion of IL-6. The etiopathology in this disease model is consistent with that of human MM. When greater than 3 × 106 KPMM2 cells were injected intravenously (IV), tumors developed in all mice and were predominantly localized in their bone marrow. Tumors were also apparent in the lymph nodes, but absent from other organs. Immunostaining of cell surface antigen (CD38) showed that more than 40% of bone marrow cells in femur were of myeloma origin in the advanced stage of tumor progression (day 37). Histologic analysis of these mice show that bone marrow was largely occupied by plasmablastic cells and bones had developed osteolytic lesions at multiple sites. Concurrently, there was a decrease in bone density throughout the body and a significant increase in ionized plasma calcium. M-protein was detected in the serum within 10 days after transplantation, which correlated with the tumor progression. Between 30 and 40 days after the transplantation, mice presented with a rapid and severe loss of body weight, hind leg paralysis, and fatigue. Subsequently, the mice died within a week. A single IV injection of 0.2 mg humanized anti–IL-6 receptor antibody (hPM1) into mice on the day after tumor transplantation substantially suppressed the elevation of serum M-protein and development of the tumor-associated abnormalities and significantly increased in the life span of tumor-bearing mice. Our data show the usefulness of this model to analyze the pathologic role of IL-6 in MM and the efficacy of targeting the IL-6 receptor in IL-6–dependent KPMM2 cells.
Immunophenotyping Investigation of Minimal Residual Disease Is a Useful Approach for Predicting Relapse in Acute Myeloid Leukemia Patients
Authors: San Miguel J.F. , Martı́nez A. , Macedo A. , Vidriales M.B. , López-Berges C. , González M. , Caballero D. , Garcı́a-Marcos M.A. , Ramos F. , Fernández-Calvo J. , Calmuntia M.J. , Diaz-Mediavilla J. , Orfao A.
Published: October 2019

A high complete remission rate is currently achieved in patients with acute myeloid leukemia (AML). However, many patients eventually relapse due to the persistence of low numbers of residual leukemic cells that are undetectable by conventional cytomorphologic criteria (minimal residual disease [MRD]). Using immunophenotypic multiparametric flow cytometry, we have investigated in sequential studies (diagnosis and follow-up) the impact of MRD detection on the outcome of 53 AML patients that had achieved morphologic remission with standard AML protocols and displayed at diagnosis an aberrant phenotype. Patients were studied at diagnosis with a panel of 35 monoclonal antibodies in triple staining combinations for detection of aberrant or uncommon phenotypic features. According to these features, a patient's probe was custom-built at diagnosis for the identification of possible residual leukemic cells during follow-up. The level of MRD at the end of induction and intensification therapy correlated with the number of relapses and relapse-free survival (RFS). Thus, patients with more than 5 × 10−3 residual cells (5 residual cells among 1,000 normal bone marrow [BM] cells) identified as leukemic by immunophenotyping in the first remission BM showed a significant higher rate of relapse (67% v 20% for patients with less than 5 × 10−3 residual cells; P = .002) and a lower median RFS (17 months v not reached; P = .01). At the end of intensification, with a cut-off value of 2 × 10−3 leukemic cells, AML patients also separated into two distinct groups with relapse rates of 69% versus 32% (P = .02), respectively, and median RFS of 16 months versus not reached (P = .04). In addition, overall survival was also significantly related to the level of residual cells in the marrow obtained at the end of induction and particularly after intensification therapy (P = .008). Furthermore, we have explored whether residual disease was related with the functional expression of multidrug resistance (MDR-1) at diagnosis as assessed by the rhodamine-123 assay. Patients with ≥5 × 10−3 residual leukemic cells at the end of induction therapy had a significantly higher rhodamine-123 efflux (mean, 56% ± 24%) than those with less than 5 × 10−3 residual cells (mean, 32% ± 31%; P = .04). Finally, multivariate analysis showed that the number of residual cells at the end of induction or intensification therapy was the most important prognostic factor for prediction of RFS. Overall, our results show that immunophenotypical investigation of MRD strongly predicts outcome in patients with AML and that the number of residual leukemic cells correlates with multidrug resistance.
Spread of Human Cytomegalovirus (HCMV) After Infection of Human Hematopoietic Progenitor Cells: Model of HCMV Latency
Authors: Zhuravskaya T. , Maciejewski J.P. , Netski D.M. , Bruening E. , Mackintosh F.R. , St Jeor S.
Published: October 2019

Clinical experience and laboratory data suggest that human cytomegalovirus (HCMV) is present in peripheral blood of seropositive individuals in a latent or persistent state and can be transmitted via blood products and be reactivated in seropositive imunocompromised patients. The pathophysiology of HCMV latency and the nature of HCMV interaction with hematopoietic cells remains unknown. In this study, we investigated the infection of bone marrow (BM) progenitor cells and their progeny as a model of HCMV latency. A clinical isolate and the recombinant laboratory strain Towne/lox containing the Escherichia coli β galactosidase (β-gal) gene regulated by immediately early (IE) HCMV promoter were used to infect highly purified CD34+ cells. Although the infection of these cells with a clinical isolate was associated with an inhibition of proliferation by 59%, an expansion of progeny derived from these cells was possible. Polymerase chain reaction analysis and staining for β-gal have shown that HCMV persisted in infected BM CD34+ cells and their progeny for up to 4 weeks. However, IE and late gene products (mRNA and protein) were detected only late in the course of infection and their expression correlated with terminal macrophage differentiation of the CD34+-derived progeny. Although early infection of CD34+ progenitor cells was not productive (as shown by the plaque assay), infectious virus could be recovered from the terminally differentiated cultures. BM progenitor cells may serve as a reservoir of the latent virus with limited transcription. Proliferation and monocytic maturation of infected progenitors may lead to the numerical expansion of HCMV-infected cells, which serve as a source of HCMV dissemination and reactivation.
Cytotoxic T Lymphocytes Specific for a Nonpolymorphic Proteinase 3 Peptide Preferentially Inhibit Chronic Myeloid Leukemia Colony-Forming Units
Authors: Molldrem Jeffrey J. , Clave Emmanuel , Jiang Yin Zheng , Mavroudis Dimitrios , Raptis Anastasios , Hensel Nancy , Agarwala Vaishali , Barrett A. John
Published: October 2019

We previously showed that a peptide (PR1) derived from the primary granule enzyme proteinase 3 induced peptide specific cytotoxic T lymphocytes (CTL) in a normal HLA-A2.1+ individual. These CTL showed HLA-restricted cytotoxicity to myeloid leukemias (which overexpress proteinase 3). To further investigate their antileukemic potential, we studied the ability of PR1-specific CTL, derived from two HLA-A2.1+ normal individuals, to inhibit colony-forming unit granulocyte-macrophage (CFU-GM) from normal and leukemic individuals. CTL from 20 day PR1 peptide-pulsed lymphocyte cultures showed 89% to 98% HLA-A2.1–restricted colony inhibition of chronic myeloid leukemia targets. Colony formation in normal HLA-A2.1+ bone marrow or HLA-A2.1− CML cells was not inhibited. Sequencing of the exon encoding PR1 showed that colony inhibition was not caused by polymorphic differences in proteinase 3 between effectors and targets. Analysis by flow cytometry showed that proteinase 3 was overexpressed in the leukemia targets compared with normal marrow targets (median channel fluorescence 1,399 v 298, P = .009). These results show that PR1-specific allogeneic T cells preferentially inhibit leukemic CFU-GM based on overexpression of proteinase 3, and that proteinase 3-specific CTL could be used for leukemia-specific adoptive immunotherapy.
A Novel, Myeloid Transcription Factor, C/EBPε, Is Upregulated During Granulocytic, But Not Monocytic, Differentiation
Authors: Morosetti Roberta , Park Dorothy J. , Chumakov Alexey M. , Grillier Isabelle , Shiohara Masaaki , Gombart Adrian F. , Nakamaki Tsuyoshi , Weinberg Kenneth , Koeffler H. Phillip
Published: October 2019

Human C/EBPε is a newly cloned CCAAT/enhancer-binding transcription factor. Initial studies indicated it may be an important regulator of human myelopoiesis. To elucidate the range of expression of C/EBPε, we used reverse transcription-polymerase chain reaction (RT-PCR) analysis and examined its expression in 28 hematopoietic and 14 nonhematopoietic cell lines, 16 fresh myeloid leukemia samples, and normal human hematopoietic stem cells and their mature progeny. Prominent expression of C/EBPε mRNA occurred in the late myeloblastic and promyelocytic cell lines (NB4, HL60, GFD8), the myelomonoblastic cell lines (U937 and THP-1), the early myeloblast cell lines (ML1, KCL22, MDS92), and the T-cell lymphoblastic leukemia cell lines CEM and HSB-2. For the acute promyelocytic leukemia cell line NB4, C/EBPε was the only C/EBP family member that was easily detected by RT-PCR. No C/EBPε mRNA was found in erythroid, megakaryocyte, basophil, B lymphoid, or nonhematopoietic cell lines. Most acute myeloid leukemia samples (11 of 12) from patients expressed C/EBPε. Northern blot and RT-PCR analyses showed that C/EBPε mRNA decreased when the HL60 and KG-1 myeloblast cell lines were induced to differentiate toward macrophages. Similarly, Western blot analysis showed that expression of C/EBPε protein was either unchanged or decreased slightly as the promyelocytic cell line NB4 differentiated down the macrophage-like pathway after treatment with a potent vitamin D3 analog (KH1060). In contrast, C/EBPε protein levels increased dramatically as NB4 cells were induced to differentiate down the granulocytic pathway after exposure to 9-cis retinoic acid. Furthermore, very early, normal hematopoietic stem cells (CD34+/CD38−), purified from humans had very weak expression of C/EBPε mRNA, but levels increased as these cells differentiated towards granulocytes. Likewise, purified granulocytes appeared to express higher levels of C/EBPε mRNA than purified macrophages. Addition of phosphothiolated antisense, but not sense oligonucleotides to C/EBPε, decreased clonal growth of HL-60 and NB4 cells by about 50% compared with control cultures. Taken together, our results indicate that expression of C/EBPε is restricted to hematopoietic tissues, especially myeloid cells as they differentiate towards granulocytes and inhibition of its expression in HL-60 and NB4 myeloblasts and promyelocytes decreased their proliferative capacity. Therefore, this transcriptional factor may play an important role in the process of normal myeloid development.
Wiskott-Aldrich Syndrome/X-Linked Thrombocytopenia: WASP Gene Mutations, Protein Expression, and Phenotype
Authors: Zhu Qili , Watanabe Chiaki , Liu Ting , Hollenbaugh Diane , Blaese R. Michael , Kanner Steven B. , Aruffo Alejandro , Ochs Hans D.
Published: October 2019

Wiskott-Aldrich syndrome (WAS) and X-linked thrombocytopenia (XLT), caused by mutations of the WAS protein (WASP) gene, represent different phenotypes of the same disease. To demonstrate a phenotype/genotype correlation, we determined WASP gene mutations in 48 unrelated WAS families. Mutations included missense (20 families) and nonsense (eight) mutations located mostly in exons 1 to 4, and splice-site mutations (seven) and deletions and insertions (13) located preferentially in exons 7 to 11. Both genomic DNA and cDNA were sequenced and WASP expression was measured in cell lysates using peptide-specific rabbit anti-WASP antibodies. WASP was expressed in hematopoietic cell lines including bone marrow–derived CD34+ cells. Missense mutations located in exons 1 to 3 caused mild disease in all but one family and permitted WASP expression, although frequently at decreased concentration. Missense mutations affecting exon 4 were associated with classic WAS and, with one exception, barely detectable WASP. Nonsense mutations caused classic WAS and lack of protein. Insertions, deletions, and splice-site mutations resulted in classic WAS and absent, unstable, truncated, or multiply spliced protein. Using affinity precipitation, WASP was found to bind to Src SH3-containing proteins Fyn, Lck, PLC-γ, and Grb2, and mutated WASP, if expressed, was able to bind to Fyn-glutathione S-transferase (GST) fusion protein. We conclude that missense mutations affecting the PH domain (exons 1 to 3) of WASP inhibit less important functions of the protein and result in a mild phenotype, and that missense mutations affecting exon 4 and complex mutations affecting the 3′ portion of WASP interfere with crucial functions of the protein and cause classic WAS.
Interleukin-7 Upregulates the Interleukin-2–Gene Expression in Activated Human T Lymphocytes at the Transcriptional Level by Enhancing the DNA Binding Activities of Both Nuclear Factor of Activated T Cells and Activator Protein-1
Authors: Gringhuis Sonja I. , F.M.H. de Leij Lou , Verschuren Emmy W. , Borger Peter , Vellenga Edo
Published: October 2019

In the present report, we studied the role of the stromal-derived cytokine interleukin-7 (IL-7) in the IL-2–gene regulation in activated T lymphocytes. Production of IL-2 requires the formation of transcription factors involved in the IL-2 –gene regulation. T-cell receptor (TCR)/CD3 engagement results in the activation of nuclear factor of activated T cells (NFAT), activator protein-1 (AP-1), and nuclear factor κB (NFκB), whereas the CD28 responsive complex (CD28RC) is activated in response to the CD28 signal. Costimulation of phytohemagglutinin/anti-CD28 activated T lymphocytes with IL-7 induces a fivefold enhanced IL-2–mRNA accumulation and a 2.5-fold enhanced protein secretion. The IL-2–gene transcription rate is increased 3.4-fold, indicating that the effect of IL-7 is in part mediated at the transcriptional level. The molecular mechanisms underlying the IL-7 effect involve the upregulation of the DNA binding activity of NFAT (60%) and AP-1 (120%), without affecting the activities of NFκB and CD28RC, which was confirmed by transfection assays. We also show that the IL-7–induced enhancement of the AP-1–DNA binding activity is not cyclosporin A-sensitive. Since AP-1 is part of the NFAT complex, we conclude that the IL-7–signaling pathway is involved in the activation of the fos and jun proteins of which AP-1 consists.
Bone Marrow Versus Peripheral Blood Progenitor Cells CD34 Selection in Patients With Non-Hodgkin's Lymphomas: Different Levels of Tumor Cell Reduction. Implications for Autografting
Authors: Lopez M. , Lemoine F.M. , Firat H. , Fouillard L. , Laporte J.P. , Lesage S. , Isnard F. , Stachowiak J. , Ferrer-Le Coeur F. , Morel P. , Najman A. , Douay L. , Gorin N.C.
Published: October 2019

Human CD34+ selected cells are able to reconstitute hematopoiesis in patients receiving a myeloablative treatment. Although the role of reinfused tumor cells contaminating the grafts on the determination of postautograft relapses remains unclear, the major interest of CD34+ cell selection is to reduce the tumor contamination of the graft. This can be achieved if tumor cells do not express the CD34 antigen. We previously showed that this approach was effective with bone marrow (BM) collections in patients with non-Hodgkin's lymphoma (NHL). Because peripheral blood progenitor cells (PBPC) allow faster hematologic recovery than BM and are expected to contain less tumor contamination, we have compared the results of CD34+ cell selection in 35 BM and 16 PBPC from 48 patients with NHL. The PBPC were collected after a course of chemotherapy followed by granulocyte colony-stimulating factor (G-CSF ) administration. The data showed that the final CD34+ cell purity achieved with PBPC was higher than with BM (medians, 70% v 50%; P = .02). The CD34+ cell recovery was also better for PBPC (medians, 42% v 24%; P = .001). Tumor contamination was assessed by detection of BCL2/JH rearrangement using polymerase chain reaction (PCR) in 38 of 48 patients (22 BM, 16 PBPC). In addition, immunoglobulin heavy chain gene (IgH) rearrangements were investigated using PCR with consensus IgH primers. At harvesting, 10 of 22 BM and two of 16 PBPC contained BCL2/JH+ cells, one of 22 BM and 14 of 16 PBPC contained abnormal IgH+ cells (one PBPC contained both BCL2/JH+ and abnormal IgH+ cells) at harvesting. However, because lymphoma tissue specimens from patients at diagnosis were not available, the malignant character of IgH rearrangements could not be confirmed by sequencing and probing with allele-specific nucleotides. After CD34+ cell selection, a reduction to below the level of detection of BCL2/JH+ cells of BM and PBPC was effective in seven of 12 informative selections. In contrast, a reduction to below the level of detection of abnormal IgH+ cells was effective in only three of 15 informative selections. However, the detection of cells with an abnormal IgH pattern in the context of chemotherapy plus G-CSF progenitor mobilization in patients with NHL and its correlation with actual tumor contamination needs further investigation.
Whole Blood Tissue Factor Procoagulant Activity Is Elevated in Patients With Sickle Cell Disease
Authors: Key Nigel S. , Slungaard Arne , Dandelet Luke , Nelson Stephen C. , Moertel Christopher , Styles Lori A. , Kuypers Frans A. , Bach Ronald R.
Published: October 2019

We developed a simple assay for the measurement of tissue factor procoagulant activity (TF PCA) in whole blood samples that avoids the need for mononuclear cell isolation. This method combines convenience of sample collection and processing with a high degree of sensitivity and specificity for TF. Using this method, we have determined that TF PCA is detectable in whole blood samples from normal individuals, which is itself a novel observation. Essentially all PCA could be shown to be localized in the mononuclear cell fraction of blood. Compared with controls, whole blood TF levels were significantly (P < .000001) elevated in patients with sickle cell disease (SCD), regardless of the subtype of hemoglobinopathy (SS or SC disease). No significant difference in TF PCA was observed between patients in pain crisis compared with those in steady-state disease. Because TF functions as cofactor in the proteolytic conversion of FVII to FVIIa in vitro, it was expected that an increase in circulating TF PCA would lead to an increased in vivo generation of FVIIa. On the contrary, FVIIa levels were actually decreased in the plasma of patients with SCD. Plasma TF pathway inhibitor (TFPI) antigen levels were normal in SCD patients, suggesting that accelerated clearance of FVIIa by the TFPI pathway was not responsible for the reduced FVIIa levels. We propose that elevated levels of circulating TF PCA may play an important role in triggering the activation of coagulation known to occur in patients with SCD. Because TF is the principal cellular ligand for FVIIa, it is possible that increased binding to TF accounts for the diminished plasma FVIIa levels.
Shear-Dependent Rolling on von Willebrand Factor of Mammalian Cells Expressing the Platelet Glycoprotein Ib-IX-V Complex
Authors: Fredrickson Becky J. , Dong Jing-Fei , McIntire Larry V. , López José A.
Published: October 2019

Mural thrombi form on exposed arterial subendothelium by a two-step process of platelet adhesion and aggregation. At high shear stresses such as are found in stenotic arteries, both steps are mediated by von Willebrand factor (vWF). Platelets initially adhere on vWF affixed to the subendothelial matrix through the glycoprotein (GP) Ib-IX-V complex. To examine the role of the GP Ib-IX-V complex under dynamic conditions, we modeled initial platelet adhesion at shear stresses ranging from 2 to 40 dyn/cm2 using vWF-coated glass slides, mammalian cells expressing full or partial GP Ib-IX-V complexes, and a parallel plate flow chamber with phase contrast video microscopy and digital image processing. Mammalian cells expressing the full complex tethered and rolled on the vWF substrate, whereas control cells did not. The rolling was completely inhibited by the monoclonal GP Ib antibody, AK2, or the vWF antibody, 5D2, both shown previously to block vWF-dependent platelet aggregation. Other GP Ib antibodies, WM23 and SZ2, did not significantly change the number or mean velocity of rolling cells. At low levels of GP Ib surface expression, cells expressing the full complex rolled slower than cells expressing the complex without GP V, indicating that GP V strengthens the interactions with the vWF surface under these conditions. Preshearing vWF for 5 minutes at 40 dyn/cm2 immediately before introducing cells into the chamber did not significantly change the number or the mean velocity of rolling cells. Inhibiting sulfation of the tyrosine residues within the GP Ib subunit reduced the number but did not change the mean velocity of the rolling cells. Our results indicate that, under the conditions of these experiments, bonds between vWF and GP Ib constantly form and break under fluid shear stress. Additionally, our results suggest that GP Ib-IX-V complexes behave like selectin receptors in their ability to mediate smooth rolling while cells maintain continuous surface contact. Such a mechanism, in vivo, would allow platelets to slow down and eventually arrest on the blood vessel wall. The system described provides a valuable approach for investigating the structure-function relationship of individual receptors and ligands in the process of platelet adhesion and thrombosis.
T-Cell Expansions With Conserved T-Cell Receptor β Chain Motifs in the Peripheral Blood of HLA-DRB1*0401 Positive Patients With Necrotizing Vasculitis
Authors: Grunewald Johan , Halapi Eva , Wahlström Jan , Giscombe Ricardo , Nityanand Soniya , Sanjeevi Carani , Lefvert Ann-Kari
Published: October 2019

T lymphocytes are implicated in the pathogenesis of systemic vasculitis such as Wegener’s granulomatosis (WG) and polyarteritis nodosa (PAN). In the present study, we have characterized in detail the T-cell receptor (TCR) of peripheral blood T cells from eight vasculitis patients of known HLA class II genotypes. We used flow cytometry to outline the exact TCR V gene expression, complementarity determining region 3 (CDR3) fragment analysis to estimate the degree of clonality and cDNA sequencing to define the exact TCR  or β chain sequences. The TCR CDR3 region interacts with antigenic peptides presented by HLA molecules, and it is normally immensely diverse. It was therefore of particular interest to identify a common dominating TCR BV8-F/L-G-G-A/Q-G-J2S3 β chain sequence in the CD4+T cells of four unrelated vasculitis patients. Furthermore, this BV8-associated CDR3 motif was linked to the HLA-DRB1*0401 allele, as well as to active disease and/or an established BV8+ CD4+ T-cell expansion. In contrast, age- and HLA-matched patients with rheumatoid arthritis did not harbor the described BV8 motif. These results strongly suggest that BV8+ CD4+ T cells with the described CDR3 motif recognize a specific antigen presented by DR4 molecules, indicating the existence of a common vasculitis-associated antigen.
AF4 Encodes a Ubiquitous Protein That in Both Native and MLL-AF4 Fusion Types Localizes to Subnuclear Compartments
Authors: Li Quanzhi , Frestedt Joy L. , Kersey John H.
Published: October 2019

Acute leukemia with t(4;11)(q21,q23) translocation results from the in-frame fusion of the MLL to the AF4/FEL gene. In previous studies, we and others demonstrated that AF4 transcripts are present in a variety of hematopoietic and nonhematopoietic human cells. To further study the wild-type and leukemia fusion AF4, we used glutathione S-transferase (GST)-fusion proteins as immunogens to produce rabbit polyclonal antibodies that were specific for normal and chimeric AF4 proteins. Using Western blotting analysis, we demonstrated that the AF4 gene encodes proteins with apparent molecular weight of 125 and 145 kD. A 45-kD protein coprecipitated with AF4 protein in immunoprecipitation. Also, the anticipated MLL-AF4–encoded 240-kD protein was detected in all cell lines with t(4;11) translocations; fusion proteins were present in lesser quantity than the wild-type AF4. The proteins recognized by the antibodies are of the predicted sizes of the AF4 and MLL-AF4–encoded proteins based on previous DNA sequencing analysis. The MLL-AF4 fusion protein had a similar subcellular distribution as AF4. Both t(4;11) and non-t(4;11) leukemic cells showed a similar pattern of punctate nuclear staining in all cell lines tested using confocal immunofluorescence microscopy. AF4 antibodies should be useful for further elucidation of the function of AF4 in normal cellular physiology, as well as the function of MLL-AF4 in leukemogenesis. The antibodies should also be helpful for the diagnosis of the MLL-AF4 fusion proteins in t(4;11) leukemias.
Selective Sp1 Binding Is Critical for Maximal Activity of the Human c-kit Promoter
Authors: Park Gyeong H. , Plummer Howard K. , Krystal Geoffrey W.
Published: October 2019

The receptor tyrosine kinase c-kit is necessary for normal hematopoiesis, the development of germ cells and melanocytes, and the pathogenesis of certain hematologic and nonhematologic malignancies. To better understand the regulation of the c-kit gene, a detailed analysis of the core promoter was performed. Rapid amplification of cDNA ends (RACE) and RNase protection methods showed two major transcriptional initiation sites. Luciferase reporter assays using 5′ promoter deletion-reporter constructs containing up to 3 kb of 5′ sequence were performed in hematopoietic and small-cell lung cancer cell lines which either did or did not express the endogenous c-kit gene. This analysis showed the region 83 to 124 bp upstream of the 5′ transcription initiation site was crucial for maximal core promoter activity. Sequence analysis showed several potential Sp1 binding sites within this highly GC-rich region. Gel shift and DNase footprinting showed that Sp1 selectively bound to a single site within this region. Supershift studies using an anti-Sp1 antibody confirmed specific Sp1 binding. Site-directed mutagenesis of the −93/−84 Sp1 binding site reduced promoter-reporter activity to basal levels in c-kit–expressing cells. Cotransfection into DrosophilaSL2 cells of a c-kit promoter-reporter construct with an Sp1 expression vector showed an Sp1 dose-dependent enhancement of expression that was markedly attenuated by mutation of the −93/−84 site. These results indicate that despite the fact that the human c-kit promoter contains multiple potential Sp1 sites, Sp1 binding is a selective process that is essential for core promoter activity.
Immunophenotypic Analysis of Peripheral Blood Mononuclear Cells Undergoing In Vitro Apoptosis After Isolation From Human Immunodeficiency Virus–Infected Children
Authors: McCloskey Thomas W. , Bakshi Saroj , Than Soe , Arman Parisa , Pahwa Savita
Published: October 2019

Lymphocytes of human immunodeficiency virus (HIV)-infected individuals undergo accelerated apoptosis in vitro, but the subsets of cells affected have not been clearly defined. This study examined the relationship between lymphocyte phenotype and apoptotic cell death in HIV-infected children by flow cytometry. Direct examination of the phenotype of apoptotic lymphocytes was accomplished using a combination of surface antigen labeling performed simultaneously with the Tdt mediated Utp nick end-labeling (TUNEL) assay. In comparison to live cells, apoptotic lymphocytes displayed an overrepresentation of CD45RO and HLA-DR expressing cells, while CD28 and CD95 expressing cells were underrepresented. Lymphocytes expressing CD4, CD8, and CD38 were equally represented in apoptotic and live populations. When percent lymphocyte apoptosis follow- ing culture was examined independently with lymphocyte subsets in fresh blood, apoptosis was negatively correlated with the percentage of CD4 cells, but not with specific CD4 T-cell subsets. Although not correlated with the percentage of total CD8 cells, apoptosis was positively correlated with specific CD8 T-cell subsets expressing CD45RO and CD95 and negatively correlated for CD8 T cells expressing CD45RA. These results provide direct evidence that a population of activated lymphocytes with the memory phenotype lacking the costimulatory molecule CD28 are especially prone to undergo apoptosis. The findings related to CD95 expression in fresh and apoptotic cells implicate Fas-dependent and Fas-independent pathways of apoptosis in HIV disease in children.
HbS-Oman Heterozygote: A New Dominant Sickle Syndrome
Authors: Nagel Ronald L. , Daar Shahina , Romero Jose R. , Suzuka Sandra M. , Gravell David , Bouhassira Eric , Schwartz Robert S. , Fabry Mary E. , Krishnamoorthy Rajagopal
Published: October 2019

Hemoglobin (Hb) S-Oman has two mutations in the β-chains. In addition to the classic βS mutation (β6 Glu → Val), it contains a second mutation in the same chain (β121 Glu → Lys) identical to that of HbOARAB. We have studied a pedigree of heterozygous carriers of HbS-Oman that segregates into two types of patients: those expressing about 20% HbS-Oman and concomitant −/ thalassemia and those with about 14% of HbS-Oman and concomitant −/− thalassemia. The higher expressors of S-Oman have a sickle cell anemia (SS) clinical syndrome of moderate intensity, while the lower expressors have no clinical syndrome, and are comparable to the solitary case first described in Oman. In addition, the higher expressors exhibit a unique form of irreversibly sickled cell reminiscent of a “yarn and knitting needle” shape, in addition to folded and target cells. The CSAT of S-Oman is identical to that of S-Antilles, another supersickling hemoglobin, whose carriers express the abnormal hemoglobin at 40% to 50%, with a very similar clinical picture to HbS-Oman. Because the level of expression is so different and the clinical picture so similar, and based on the hemolysates CSAT’s, we conclude that HbS-Oman produces pathology beyond its sickling tendencies. A clue for this additional pathogenesis is found in the fact that homozygous HbOARAB, which has the same second substitution as S-Oman, has a moderately severe hemolytic anemia; when HbOARAB is combined with HbS, it makes the phenotype of this double heterozygote as severe as SS. Properties of HbS-Oman red blood cells (RBCs) include reticulocytes that are much denser than normal (similar to those of SC and CC disease), a decrease in the Km for Ca2+ needed to activate the Gardos’ channel (making this transporter more sensitive to Ca2+), increased association of HbS-Oman with the RBC membrane, the presence of dense cells by isopycnic gradient, the presence of folded cells, and abundant nidus of polymerization under the membrane. Other properties include a clear increase in volume and N-ethylmaleimide–stimulated K:Cl cotransport in RBCs expressing more than 20% HbS-Oman. We conclude that the pathology of heterozygous S-Oman is the product of the sickling properties of the β6 Val mutation which are enhanced by the second mutation at β121. In addition, the syndrome is further enhanced by a hemolytic anemia induced by the mutation at β121. We speculate that this pathology results from the abnormal association of the highly positively charged HbS-Oman (3 charges different from normal hemoglobin) with the RBC membrane.
Adhesion to Fibronectin Maintains Regenerative Capacity During Ex Vivo Culture and Transduction of Human Hematopoietic Stem and Progenitor Cells
Authors: Dao M.A. , Hashino K. , Kato I. , Nolta J.A.
Published: October 2019

Recent reports have indicated that there is poor engraftment from hematopoietic stem cells (HSC) that have traversed cell cycle ex vivo. However, inducing cells to cycle in culture is critical to the fields of ex vivo stem cell expansion and retroviral-mediated gene therapy. Through the use of a xenograft model, the current data shows that human hematopoietic stem and progenitor cells can traverse M phase ex vivo, integrate retroviral vectors, engraft, and sustain long-term hematopoiesis only if they have had the opportunity to engage their integrin receptors to fibronectin during the culture period. If cultured in suspension under the same conditions, transduction is undetectable and the long-term multilineage regenerative capacity of the primitive cells is severely diminished.
Immunotherapy of B-Cell Lymphoma With CD3x19 Bispecific Antibodies: Costimulation via CD28 Prevents “Veto” Apoptosis of Antibody-Targeted Cytotoxic T Cells
Authors: Daniel Peter T. , Kroidl Arne , Kopp Joachim , Sturm Isrid , Moldenhauer Gerhard , Dörken Bernd , Pezzutto Antonio
Published: October 2019

Bispecific antibodies (CD3x19) against the CD3ɛ-chain of the T-cell–receptor/CD3 complex and the CD19 antigen on B cells can target polyclonal, nontumor-specific T cells to B lymphoma cells. This induces T-cell activation, and generation of cytotoxic T cells (CTLs). These polyclonal CTLs, targeted by the CD3x19 bispecific antibodies, can lyse CD19+ B-lymphoma cells. In a xenotransplant model in severe combined immunodeficiency deficient (SCID) mice, we and others observed that CD28 triggering is required for efficient elimination of B-lymphoma cells and cure from the tumor in addition to CD3x19 administration. We also showed that the activation and targeting of CTLs to the target cell by signal one alone, ie, the CD3x19 mab, induces T-cell death by apoptosis. In blocking experiments we showed that this “veto” apoptosis is mediated by the CD95/Fas ligand. Addition of anti-CD28 (signal 2) renders the T cells resistant for veto apoptosis both in vitro and in vivo. We therefore conclude that the role of costimulation in immunotherapy with bispecific antibodies or other T-cell–based immune strategies is not only to facilitate T-cell activation but also to prevent T-cell deletion by apoptosis.