bluuebunny/crossref_metadata_2025 huggingface dataset:
Oligonucleotide uptake in human hematopoietic cells is increased in leukemia and is related to cellular activation
Authors: Zhao Q , Song X , Waldschmidt T , Fisher E , Krieg AM
Published: October 2019

The use of antisense oligonucleotides as tools for modulating gene expression represents a novel strategy for designing drugs to treat a variety of diseases. Several factors, including cellular uptake and internalization of the oligonucleotides, are important parameters in determining the effectiveness of antisense agents such as therapeutic drugs. We have studied oligonucleotides uptake in normal and leukemic human hematopoietic cells, such as peripheral blood, bone marrow (BM), and HL-60 cell line; and have found that, in normal human blood and BM, myeloid cells and B cells preferably took up more oligonucleotides than T cells. There was no marked difference in oligonucleotide uptake between CD4+ helper T cells and CD8+ cytolytic T cells. Leukemic cells had greater oligonucleotide uptake than their normal counterparts. Furthermore, oligonucleotide uptake was closely related to cell activation status and can be modulated by growth factors or inhibitors. These studies provide a basis for using oligonucleotides as therapeutic drugs both in vitro and in vivo.
Platelet and Fibrin Deposition at the Damaged Vessel Wall: Cooperative Substrates for Neutrophil Adhesion Under Flow Conditions
Authors: Kuijper P.H.M. , Torres H.I. Gallardo , Lammers J.-W.J. , Sixma J.J. , Koenderman L. , Zwaginga J.J.
Published: October 2019

At sites of vessel wall damage, the primary hemostatic reaction involves platelet and fibrin deposition. At these sites, circulating leukocytes marginate and become activated. Adhered platelets can support leukocyte localization; however, the role of fibrin in this respect is not known. We studied the adhesion of human neutrophils (polymorphonuclear leukocytes [PMNs]) to endothelial extracellular matrix (ECM)-bound fibrin and platelets under flow conditions. ECM alone did not show PMN adhesion. ECM-coated cover slips were perfused with plasma to form a surface-bound fibrin network, and/or with whole blood to allow platelet adhesion. Unstimulated PMNs adhered to fibrin at moderate shear stress (20 to 200 mPa). ECM-bound platelets induced rolling adhesion and allowed more PMNs to adhere at higher shear (320 mPa). ECM coated with both platelets and fibrin induced more static and shear-resistant PMN adhesion. PMN adhesion to fibrin alone but not to platelet/fibrin surfaces was inhibited by soluble fibrinogen. Adhesion to fibrin alone was inhibited by CD11b and CD18 blocking antibodies. Furthermore, fibrin formed under flow conditions showed up to threefold higher PMN adhesion compared with fibrin formed under static conditions, due to structural differences. These results indicate that circulating PMNs adhere to fibrin in an integrin-dependent manner at moderate shear stresses. However, at higher shear rates (<200 mPa), additional mechanisms (ie, activated platelets) are necessary for an interaction of PMNs with a fibrin network.
Severe Factor VII Deficiency Due to a Mutation Disrupting a Hepatocyte Nuclear Factor 4 Binding Site in the Factor VII Promoter
Authors: Arbini Arnaldo A. , Pollak Eleanor S. , Bayleran Janet K. , High Katherine A. , Bauer Kenneth A.
Published: October 2019

Although small deletions, splice site abnormalities, missense, and nonsense mutations have been identified in patients with factor VII deficiency, there have been no reports of mutations in the factor VII promoter. We investigated a girl with factor VII levels that were less than 1% of normal in association with a severe bleeding diathesis. The patient is homozygous for a T to G transversion that occurs 61 bp before the translation start site. This nucleotide is in a sequence that is an hepatocyte nuclear factor 4 (HNF-4) binding site within the factor VII promoter (ACTTTG Æ → ACGTTG). Using gel mobility shift assays, we show that the mutation disrupts the binding of HNF-4 to its cognate binding site. In growth hormone reporter gene assays, the activity of a plasmid containing the mutant promoter was 6.7% of the wild-type promoter plasmid. Although HNF-4 was able to transactivate the wild-type factor VII promoter 5.4-fold in HeLa cells, no transactivation could be shown with the mutant promoter. These findings indicate that HNF-4 exerts a major positive regulatory effect on factor VII expression and provides in vivo evidence that binding of this transcription factor is critical for normal factor VII expression.
Telomerase Activity in Reactive and Neoplastic Lymphoid Tissues: Infrequent Detection of Activity in Hodgkin's Disease
Authors: Brousset Pierre , Al Saati Talal , Chaouche Nadia , Zenou Reine-Claude , Schlaifer Daniel , Chittal Shashikant , Delsol Georges
Published: October 2019

We used the recently described sensitive and rapid detection assay called telomeric repeat amplification protocol (TRAP) to detect telomerase activity in lymphoblastoid (n = 5) and lymphoma cell lines (n = 7), hyperplastic lymph nodes (n = 6) and tonsils (n = 5), and tissues involved by non-Hodgkin's lymphoma (NHL) (n = 43) and Hodgkin's disease (HD) (n = 14). Clearly evident telomerase activity was found in all lymphoblastoid and lymphoma cell lines, and in 34 of 43 cases (80%) of NHL. These results were expected because of the proliferative and immortal nature of the cell lines and most malignant cells. However, positive results were obtained with the TRAP assay in all hyperplastic lymph nodes and tonsils, which raises the issue of derepression of telomerase activity during an immune response. Telomerase activity alone therefore does not distinguish malignant lymphoid proliferations from reactive states. Telomerase activity was detected in only 1 of 14 cases (7%) of lymphoid tissues involved by HD. Eight of the 13 negative cases were considered to be interpretable because of the lack (3 of 13 cases) or low level (5 of 13 cases) of telomerase inhibition. The five remaining cases could not be evaluated because of their telomerase inhibitor content. The findings imply either transient or very low levels of telomerase activity in HD or that HD for the greater part is a telomerase-independent neoplasm. Microdissection studies are needed to identify subsets of cells carrying telomerase activity in both reactive and neoplastic lymphoid tissues.
Limits of the Human-PBL-SCID Mice Model: Severe Restriction of the Vβ T-Cell Repertoire of Engrafted Human T Cells
Authors: Garcia Sylvie , Dadaglio Gilles , Gougeon Marie-Lise
Published: October 2019

A recent study in the human-peripheral blood lymphocytes-severe combined immunodeficiency (hu-PBL-SCID) model, analyzing the specificity of the engrafted human T cells, showed that human T-cell lines and clones derived from engrafted cells presented a xenoreactivity toward murine host molecules. This observation raised the question of the influence of the SCID environment on the ex vivo repertoire and function on the human T cells reconstituting the murine host. We have characterized the human Vβ repertoire in the spleen of hu-PBL-SCID mice 1 to 3 months after their engraftment. Fluorescence-activated cell sorting (FACS) analysis of human Vβ T-cell representation showed that, for all chimeras, all tested Vβ subsets were submitted to underrepresentation and/or expansion upon engraftment. Importantly, these quantitative modifications of the T-cell repertoire were associated with a severe restriction in both the CDR3 size distribution pattern of the Vβ transcripts and the number of Jβ segments used by these transcripts. In addition, ex vivo phenotypic characterization of engrafted cells showed that 70% to 100% expressed the activation markers HLA-DR, CD45RO, and CD38. Taken together, these results suggest that, following their engraftment, human T cells were submitted to a massive antigenic selection. Moreover, we found that these activated T cells were unresponsive to in vitro mitogenic and superantigenic activation. The consequences of the skewed repertoire and altered function of engrafted human T cells on the validity of this humanized murine model are discussed.
Major Histocompatibility Complex Restriction Between Hematopoietic Stem Cells and Stromal Cells In Vivo
Authors: Hashimoto Futoshi , Sugiura Kikuya , Inoue Kyoichi , Ikehara Susumu
Published: October 2019

Graft failure is a mortal complication in allogeneic bone marrow transplantation (BMT); T cells and natural killer cells are responsible for graft rejection. However, we have recently demonstrated that the recruitment of donor-derived stromal cells prevents graft failure in allogeneic BMT. This finding prompted us to examine whether a major histocompatibility complex (MHC) restriction exists between hematopoietic stem cells (HSCs) and stromal cells. We transplanted bone marrow cells (BMCs) and bones obtained from various mouse strains and analyzed the cells that accumulated in the engrafted bones. Statistically significant cell accumulation was found in the engrafted bone, which had the same H-2 phenotype as that of the BMCs, whereas only few cells were detected in the engrafted bones of the third-party H-2 phenotypes during the 4 to 6 weeks after BMT. Moreover, the BMCs obtained from the MHC-compatible bone showed significant numbers of both colony-forming units in culture (CFU-C) and spleen colony-forming units (CFU-S). These findings strongly suggest that an MHC restriction exists between HSCs and stromal cells.
Prevalence and Growth Characteristics of Malignant Stem Cells in B-Lineage Acute Lymphoblastic Leukemia
Authors: Nishigaki Hikari , Ito Chikako , Manabe Atsushi , Kumagai Masa-aki , Coustan-Smith Elaine , Yanishevski Yuri , Behm Frederick G. , Raimondi Susana C. , Pui Ching-Hon , Campana Dario
Published: October 2019

We used a stroma-supported culture method to study the prevalence and growth characteristics of malignant stem cells in acute lymphoblastic leukemia (ALL). In 51 of 108 B-lineage ALL samples, bone marrow-derived stroma not only inhibited apoptosis of ALL cells but also supported their proliferation in serum-free medium. When single leukemic cells were placed in the stroma-coated wells of microtiter plates, the percentage of wells with leukemic cell growth after 2 to 5 months of culture ranged from 6% to 20% (median, 15%; 5 experiments). The immunophenotypes and genetic features of cells recovered from these cultures were identical to those noted before culture. All cells maintained their stroma dependency and self-renewal capacity. Leukemic clones derived from single cells contained approximately 103 to 106 cells after 1 month of culture; other clones became detectable only after prolonged culture. Cell growth in stroma-coated wells correlated with the number of initially seeded cells (1 or 10; r = .87). However, the observed percentages of positive wells seeded with 10 cells always exceeded values predicted from results with single-cell–initiated cultures (P < .003 by paired t-test), suggesting stimulation of leukemic cell growth by paracrine factors. In conclusion, the proportion of ALL cells with clonogenic potential may be considerably higher than previously thought.
Vesicular Anthracycline Accumulation in Doxorubicin-Selected U-937 Cells: Participation of Lysosomes
Authors: Hurwitz Selwyn J. , Terashima Masanori , Mizunuma Nobuyuki , Slapak Christopher A.
Published: October 2019

The U-A10 cell line, a doxorubicin-selected variant of human U-937 myeloid leukemia cells, exhibits a redistribution of anthracyclines into a expanded vesicular compartment. The acidic nature of this compartment was confirmed by vital staining with a pH sensitive dye, LysoSensor yellow/blue DND-160. Identification of the vesicular compartment was performed by immunofluorescence analysis. Staining for the LAMP-1 and LAMP-2 antigens showed that the vesicles are enlarged lysosomes that are eccentrically placed near the nucleus of U-A10 cells. By contrast, the expression of the multidrug resistance-associated protein and the P-glycoprotein was observed predominately on the plasma membrane of the drug-resistant cells. The accumulation of daunorubicin into cellular compartments was quantified using radiolabeled drug. Exposing cells to 3[H]-daunorubicin and then isolating intact nuclei showed that nuclei from U-A10 cells accumulated twofold to threefold less anthracycline than nuclei from U-937 cells. However, when nuclei were isolated first and then exposed to 3[H]-daunorubicin, little difference in net nuclear drug accumulation was detected. Cytoplasts prepared from U-A10 and U-937 cells were exposed to 3[H]-daunorubicin to measure cytoplasmic drug accumulation. At external daunorubicin concentrations of 100 ng/mL or higher, cytoplasts from U-A10 cells accumulated significantly more daunorubicin than cytoplasts from U-937 cells. Moreover, studies with the lysosomotropic agent chloroquine showed that U-A10 cells accumulated twofold more chloroquine and showed twofold enhanced sensitivity to this agent as compared with parental U-937 cells. Fluorescence microscopy showed that chloroquine affects vesicular anthracycline sequestration in U-A10 cells with an associated increase in daunorubicin nuclear fluorescence. Although chloroquine did not alter anthracycline cytotoxicity in parental cells, it restored daunorubicin and doxorubicin sensitivity to U-A10 cells. Taken together, these studies demonstrate that U-A10 cells exhibit a redistribution of the lysosomal compartment. The trapping of drug into an expanded acidic vesicular compartment results in decreased nuclear drug accumulation and decreased cytotoxicity. Lysosomotropic agents, such as chloroquine, warrant further study as modulators of this acquired drug-resistance phenotype.
Lack of t(14; 18) Polymerase Chain Reaction-Positive Cells in Highly Purified CD34+ Cells and Their CD19 Subsets in Patients With Follicular Lymphoma
Authors: Voso Maria Teresa , Hohaus Stefan , Moos Marion , Haas Rainer
Published: October 2019

Follicular lymphoma (FL) is characterized in a significant proportion of cases by the t(14; 18) chromosomal translocation, which results in the juxtaposition of the oncogene bcl-2 to the joining region of the immunoglobulin heavy chain (IgH) gene. Molecular sequence analysis indicates that the t(14; 18) rearrangement occurs in a B-lymphoid progenitor cell at the time of IgH rearrangement. We were interested whether hematopoietic stem and progenitor cells as characterized by CD34 expression bear the translocation. Bone marrow (BM)-CD34+ cells were enriched from 14 patients with FL whose BM was known to be positive for bcl-2/IgH (major breakpoint region [MBR]). Six patients were in complete remission (CR), two patients were in partial remission (PR), and six patients had active disease. Six patients had histological BM involvement when the samples were obtained. Using an immunomagnetic selection device (MINIMACS), a mean purity of 88.7% ± 4% CD34+ cells was achieved. The CD34+ cells were further enriched by fluorescence activated cell sorting (FACS) using CD34 fluorescein isothiocyanate (FITC)- and CD19 phycoerythrin (PE)-conjugated antibodies. The IgH gene was rearranged in the CD34+/CD19+ cell subset of all patients assessed by polymerase chain reaction (PCR). This population is thought to represent the progenitor stage at which the bcl-2/IgH translocation occurs. The unseparated BM mononuclear cell fraction from all 14 patients was positive for bcl-2/IgH using a nested PCR, but the BM-CD34+ cell fraction and the respective CD34+/CD19+ subset were negative in 13 of these 14 patients. The one patient with a positive PCR signal in the CD34+ cell subset had a relapse with BM involvement. We conclude that CD34+ progenitor cells including CD34+/CD19+ B-cell progenitors are not involved in the malignant cell clone. These data are in agreement with a transgenic mouse model, which indicates that the malignant phenotype in FL is sustained by mature B cells.
Autologous Tumor Infiltrating T Cells Cytotoxic for Follicular Lymphoma Cells Can Be Expanded In Vitro
Authors: Schultze Joachim L. , Seamon Mark J. , Michalak Sabine , Gribben John G. , Nadler Lee M.
Published: October 2019

Follicular lymphomas (FLs) rarely induce clinically significant T-cell–mediated responses. We showed that freshly isolated tumor infiltrating T cells (T-TILs) lack tumor-specific cytotoxicity. Stimulation of these T cells with FL cells in the presence of interleukin-2 (IL-2) and/or costimulation via CD28 does not lead to T-cell activation and expansion. In contrast, when stimulated with FL cells preactivated via CD40, autologous T-TILs can be expanded by the addition of exogenous IL-2. These T cells can be further expanded in vitro by the addition of exogenous IL-4, IL-7, or interferon-γ, but not IL-12. Once activated, these T cells showed FL-directed cytotoxicity in four of five patients tested. We concluded that autologous cytotoxic anti-FL–specific T cells exist, but can only be detected in vitro under optimized conditions for T-cell stimulation and expansion. This suggests that their frequency in vivo is either very low or that the microenvironment does not provide the necessary signals to activate these T cells. This model system allows dissection of the requisite conditions for activation and expansion of lymphoma-directed cytotoxicity and may permit expansion of previously activated cytotoxic T cells for adoptive transfer.
Molecular Characterization of IgA- and/or IgG-Switched Chronic Lymphocytic Leukemia B Cells
Authors: Matolcsy András , Casali Paolo , Nádor Roland G. , Liu Yi-Fang , Knowles Daniel M.
Published: October 2019

The immunoglobulin (Ig) variable region (V) genes expressed by IgM chronic lymphocytic leukemia (CLL) B cells display little or no somatic mutations. However, preliminary findings have shown that Ig V genes of IgA and IgG CLLs may be somatically mutated, suggesting that isotype-switched CLLs may represent a “subtype” of the disease. To investigate the degree and nature of somatic mutations and the role of antigen (Ag) in the clonal selection and expansion of isotype-switched CLLs, and to determine whether specific oncogene or tumor suppressor gene mutations are associated with isotype-switched CLLs, we analyzed the expressed Ig VH gene, bcl-1 and bcl-2 proto-oncogene, and p53 tumor suppressor gene configurations of 3 IgA-, 1 IgG-, and 1 IgA/IgG-expressing CLLs. These isotype-switched CLL B cells expressed surface HLA-DR, CD19, CD23, and CD5, and displayed no alterations of the bcl-1 and bcl-2 oncogenes and the p53 tumor-suppressor gene. The cDNA VH -D-JH gene sequence was joined with that of the Cα gene in the B cells of the three IgA CLLs, and with that of the Cγ gene in the IgG CLL B cells. In the IgA/IgG-coexpressing CLL B cells, identical VH -D-JH cDNA sequences were spliced to either Cα or Cγ genes. In all five CLLs, the pattern of Cμ DNA probe hybridization to the digested genomic DNAs was consistent with deletion of the Cμ exon from the rearranged Ig gene locus, suggesting that these CLL B cells had undergone DNA switch recombination. In one IgA CLL, the expressed VH gene was unmutated. In all other class-switched CLLs, the Ig VH segment gene was mutated, but the point mutations were not associated with intraclonal diversification. In one IgA and in the IgA/IgG-coexpressing CLL, the nature and distribution of the mutations were consistent with Ag selection. These findings suggest that IgA- and/or IgG-expressing CLLs represent, in their VH gene structure, transformants of B cells at different stages of ontogeny. They also suggest that Ag may play a role in the clonal selection of some of these isotype-switched leukemic cells, but bcl-1 and bcl-2 oncogene rearrangements and p53 tumor suppressor gene mutation are not associated with the pathogenesis of isotype-switched CLLs.
The Unusual Pathobiology of Hemoglobin Constant Spring Red Blood Cells
Authors: Schrier S.L. , Bunyaratvej A. , Khuhapinant A. , Fucharoen S. , Aljurf M. , Snyder L.M. , Keifer C.R. , Ma L. , Mohandas N.
Published: October 2019

Hemoglobin Constant Spring (HbCS) is the most common nondeletional α-thalassemic mutation and is an important cause of HbH-like disease in Southeast Asia. HbCS variants have an almost normal mean cell volume (MCV) and the anemia is more severe when compared with other α-thalassemic variants. We explored the pathobiology of HbCS red blood cells (RBCs) because the underlying cause(s) of this MCV “normalizing” effect of HbCS and the more severe anemia are not fully explained. HbCS containing RBCs are distinctly overhydrated relative to deletional α-thalassemia variants, and the derangement of volume regulation and cell hydration occurs early in erythroid maturation and is fully expressed at the reticulocyte stage. Furthermore, the membrane rigidity and membrane mechanical stability of HbCS containing RBCs is increased when compared with HbH and α-thalassemia-1 trait RBCs. In seeking the cause(s) underlying these cellular alterations we analyzed membranes from HbCS and deletional α-thalassemic variants and found that in addition to oxidized β-globin chains, oxidized αcs-globin chains are also associated with the membranes and their skeletons in HbCS containing RBCs. We propose that the membrane pathology of HbCS variants is caused by combination of the deleterious effects induced by membrane-bound oxidized αcs- and β-globin chains. The membrane alterations induced by αcs chains are more akin to those induced by βA-globin chains than those induced by the αA-globin chains that accumulate in the β-thalassemias. Thus, each globin chain, αcs, αA, βA, appears to produce its own form of membrane perturbation.
Molecular Analysis of Rh Transcripts and Polypeptides From Individuals Expressing the DVI Variant Phenotype: An RHD Gene Deletion Event Does Not Generate All DVIccEe Phenotypes
Authors: Avent Neil D. , Liu Wendy , Jones Jeff W. , Scott Marion L. , Voak Douglas , Pisacka Martin , Watt Julie , Fletcher Anne
Published: October 2019

The D antigen is a mosaic comprising at least 30 epitopes. Partial Rh D phenotypes occur when there is absence of one or more of these epitopes, with the remainder expressed. The DVI phenotype is the most common of the partial D phenotypes, lacking most D antigen epitopes (ep D) (epD1, 2, 5-8 using the 9-epitope model or epD 1-4,7-22, 26-29 using the 30-epitope model). DVI mothers may become immunized by transfusion with D-positive blood (if typed as D-positive using polyclonal typing reagents) or by fetuses which have all of the D antigen. This situation can give rise to severe hemolytic disease of the newborn (HDN). The molecular basis of the DVI phenotype has previously been proposed to occur by two different genetic mechanisms, one (in individuals of DVICcee phenotype) where a gene conversion event generates a hybrid RHD-RHCE-RHD gene; the second (in individuals of DVIccEe phenotype) was proposed to be caused by a partial RHD gene deletion. We present evidence that in four DVICcee phenotypes studied, this phenotype is not generated by a partial RHD gene deletion, but occurs by a similar mechanism to the DVICcee phenotypes. In two individuals we have found hybrid RHD-RHCE-RHD transcripts in both DVICe and DVIcE haplotypes. These differ in that the DVICe transcripts are derived from an RHD gene where exons 4-6 have been replaced with RHCE equivalents (encoding Ala226 ); the DVIcE transcripts are derived from an RHD gene where exons 4 and 5 are replaced by RHCE equivalents (encoding Pro226 ). We provide direct evidence that Rh DVI polypeptides are expressed at the erythrocyte surface as full-length polypeptide products. We have used immunoprecipitation experiments using anti-D reactive with DVI erythrocytes followed by immunoblotting the immune complexes with rabbit sera immunoreactive to the fourth external and C-terminal domains of all Rh polypeptides. Our results illustrate that these domains are present on all Rh DVI proteins studied, and suggest that Rh DVI polypeptide species studied here exist as full-length Rh proteins.
Acute Chest Syndrome in Sickle Cell Disease: Clinical Presentation and Course
Authors: Vichinsky Elliott P. , Styles Lori A. , Colangelo Linda H. , Wright Elizabeth C. , Castro Oswaldo , Nickerson Bruce ,   the Cooperative Study of Sickle Cell Disease
Published: October 2019

Acute chest syndrome (ACS) is an important cause of morbidity and mortality in sickle cell disease (SCD). Previous studies reported conflicting pictures of ACS making therapeutic interventions difficult. The Cooperative Study of Sickle Cell Disease prospectively followed 3,751 patients enrolled from birth to 66 years of age for ACS. Data on presenting signs and symptoms, laboratory findings, and hospital course were collected. There were 1,722 ACS episodes in 939 patients. Young children (age 2 to 4 years) presented with fever and cough, a negative physical exam, and rarely had pain. Adults were often afebrile and complained of shortness of breath, chills, and severe pain. Upper lobe disease was more common in children; multilobe and lower lobe disease affected adults more often. Severe hypoxia occurred in 18% of adults tested and could not be predicted by examination or laboratory findings. Bacteremia was documented in 3.5% of episodes, but was strongly influenced by age (14% of infants and 1.8% of patients <10 years). ACS was most common in winter with children having the most striking increase. Transfusion was used less frequently, but earlier in children. Young children were hospitalized for 5.4 days versus 9 days for adults. Fifty percent of adults had a pain event in the 2 weeks preceding ACS and children were more likely to have febrile events. The death rate was four times higher in adults than in children. Fatal cases generally developed rapid pulmonary failure and one third were associated with bacteremia. Age has a striking effect on the clinical picture of ACS. In children, ACS was milder and more likely due to infection, whereas in adults ACS was severe, associated with pain and had a higher mortality rate.
Deficient Activity of von Willebrand Factor–Cleaving Protease in Chronic Relapsing Thrombotic Thrombocytopenic Purpura
Authors: Furlan Miha , Robles Rodolfo , Solenthaler Max , Wassmer Max , Sandoz Pierre , Lämmle Bernhard
Published: October 2019

In patients with thrombotic thrombocytopenic purpura (TTP), excessive intravascular platelet aggregation has been associated with appearance in plasma of unusually large von Willebrand factor (vWF ) multimers. These extremely adhesive vWF multimers may arise due to deficiency of a “depolymerase” cleaving vWF to smaller molecular forms, either by reducing the interdimeric disulfide bridges or by proteolytic degradation. We studied the activity of a recently described vWF-cleaving protease in four patients with chronic relapsing TTP. Diluted plasma samples of TTP patients were incubated with purified normal human vWF in the presence of a serine protease inhibitor, at low ionic strength, and in the presence of urea and barium ions. The extent of vWF degradation was assayed by electrophoresis in sodium dodecyl sulfate-agarose gels and immunoblotting. Four patients, that included two brothers, with chronic relapsing TTP displayed either substantially reduced levels or a complete absence of vWF-cleaving protease activity. In none of these patient plasmas was an inhibitor of or an antibody against the vWF-cleaving protease established. Our data suggest that the unusually large vWF multimers found in TTP patients may be caused by deficient vWF-cleaving protease activity. Deficiency of this protease may be inherited in an autosomal recessive manner and seems to predispose to chronic relapsing TTP. The assay of the vWF-cleaving protease activity may be used as a sensitive diagnostic tool for identification of subjects with a latent TTP tendency.
Activation of the NF-κB Pathway by Inflammatory Stimuli in Human Neutrophils
Authors: McDonald Patrick P. , Bald Anette , Cassatella Marco A.
Published: October 2019

Activated neutrophils have the ability to upregulate the expression of many genes, in particular those encoding cytokines and chemokines, and to subsequently release the corresponding proteins. Although little is known to date concerning the regulation of gene transcription in neutrophils, it is noteworthy that many of these genes depend on the activation of transcription factors, such as NF-κB, for inducible expression. We therefore investigated whether NF-κB/Rel proteins are expressed in human neutrophils, as well as their fate on cell activation. We now report that dimers consisting of p50 NFκB1, p65 RelA, and/or c-Rel are present in neutrophils and that the greater part of these protein complexes is physically associated with cytoplasmic IκB-α in resting cells. Following neutrophil stimulation with proinflammatory agonists (such as lipopolysaccharide [LPS], tumor necrosis factor-α [TNF-α], and fMet-Leu-Phe) that induce the production of cytokines and chemokines in these cells, NF-κB/Rel proteins translocated to nuclear fractions, resulting in a transient induction of NF-κB DNA binding activity, as determined in gel mobility shift assays. The onset of both processes was found to be closely paralleled by, and dependent on, IκB-α degradation. Proinflammatory neutrophil stimuli also promoted the accumulation of IκB-α mRNA transcripts, resulting in the reexpression of the IκB-α protein. To our knowledge, this constitutes the first indication that NF-κB activation may underlie the action of proinflammatory stimuli towards human neutrophil gene expression and, as such, adds a new facet to our understanding of neutrophil biology.
Platelet Determination by Turbidimetry
Authors: CRUZ W. O.
Published: October 2019

A method to determine the amount of circulating platelets without the aid of any special apparatus is described. The method consists in separating the platelets from the other blood elements by fractional centrifugation and in measuring the light absorption of the platelet suspension in a photoelectric apparatus. Light absorption is standardized against the platelet volume found by the Van Allen thrombocytocrit, and results presented as platelet volume in 100 ml. of bood.

The error of the method was found to be 6 per cent. To test the consistency of the method, normal dogs and patients of both sexes with different pathologic conditions were studied, the results agreeing with the data found in the literature. In dogs of both sexes, twenty males showed 0.50 ml. per 100 ml. blood with a standard deviation of ±0.15, and ten females 0.53 ml./100 ml. ±0.17; fiftytwo male patients showed 0.45 ml. per 100 ml. of blood with a standard deviation of ±0.20, and thirty-one females 0.44 ml./100 ml. ±0.23.

Still further to test the reliability of the method, a confirmation was undertaken of the fact of platelet increase in the postoperative period in major surgical interventions. Twenty-seven patients with 0.38 ml./100 ml. (±0.16 as standard deviation) platelets showed soon after the operation 0.44 ml./100 ml. ±0.19 a difference not significant according to statistical tests; eleven days after the operation, average platelets were 0.60 ± 0.21 ml./100 ml. a highly significant increase.
Phenotypic Consequences of Mutations in the Fanconi Anemia FAC Gene: An International Fanconi Anemia Registry Study
Authors: Gillio Alfred P. , Verlander Peter C. , Batish S.D. , Giampietro P.F. , Auerbach Arleen D.
Published: October 2019

Fanconi anemia (FA) is a genetically and phenotypically heterogeneous disorder defined by cellular hypersensitivity to DNA cross-linking agents; mutations in the gene defective in FA complementation group C, FAC, are responsible for the syndrome in a subset of patients. We have performed an analysis of the clinical effects of specific mutations in the FAC gene. Using the amplification refractory mutation system assays that we developed to rapidly detect FAC mutations, at least one mutated copy of the FAC gene was identified in 59 FA patients from the International Fanconi Anemia Registry (IFAR). This represents 15% of the 397 FA patients tested. FA-C patients were divided into three subgroups based on results of a genotype-phenotype analysis using the Cox proportional hazards model: (1) patients with the IVS4 mutation (n = 26); (2) patients with at least one exon 14 mutation (R548X or L554P) (n = 16); and (3) patients with at least one exon 1 mutation (322delG or Q13X) and no known exon 14 mutation (n = 17). Kaplan-Meier analysis shows that IVS4 or exon 14 mutations define poor risk subgroups, as they are associated with significantly earlier onset of hematologic abnormalities and poorer survival compared to exon 1 patients and to the non-FA-C IFAR population. There was no direct correlation between the degree of cellular hypersensitivity to the clastogenic effect of diepoxybutane and severity of clinical phenotype. Sixteen of the 59 FA-C patients (27%) have developed acute myelogenous leukemia. Thirteen of these patients have died; AML was the cause of death in 46% of the expired FA-C patients. This study enables us to define this clinically heterogeneous disorder genotypically to better predict clinical outcome and aid decision-making regarding major therapeutic modalities for a subset of FA patients.
Specific Domains of Fibronectin Mediate Adhesion and Migration of Early Murine Erythroid Progenitors
Authors: Goltry Kristin L. , Patel Vikram P.
Published: October 2019

The binding of late stage erythroid cells to fibronectin (FN) has been well characterized and is believed to be critical for the terminal stages of erythroid differentiation, but the adhesive properties of more primitive murine erythroid progenitors and the role of these interactions during earlier stages of erythropoiesis has not been determined. Using chymotryptic fragments and inhibitory probes, we have tested the ability of each of the major cell binding domains of FN; the RGDS sequence, the CS-1 sequence, and the carboxy-terminal heparin-binding domain (HBD), to promote adhesion of primitive burst-forming unit-erythroid (BFU-E), mature BFU-E, and colony-forming unit-erythroid (CFU-E). We found that only 10% to 15% of BFU-E bound to FN or to the RGDS sequence in contrast to 75% to 85% of CFU-E. Approximately 50% to 70% of BFU-E and 60% to 80% of CFU-E bound to the carboxy-terminal HBD and to the CS-1 sequence. The binding of BFU-E and CFU-E to the RGDS and CS-1 sites was blocked by β1 integrin antibodies. These results suggest that binding to FN determinants is developmentally regulated during early erythroid differentiation. Erythroid progenitor migration within the bone marrow is thought to be important for the eventual release of reticulocytes into the circulation. A correlation between FN binding and the migratory capacity of erythroid cells has been suggested, although the ability of FN to promote migration of erythroid progenitors has not been directly measured. We measured migration of CFU-E on fragments of FN containing each cell binding region. CS-1–containing fragments, in addition to promoting adhesion of both BFU-E and CFU-E, supported the highest levels of CFU-E migration (11-fold above background). Migration was sixfold above background on intact FN and only threefold above background on RGDS-containing fragments. Fragments containing HBD alone, although they promoted adhesion of CFU-E, failed to support significant levels of migration. These results show that specific domains of FN possess distinct adhesion- and migration-promoting properties for murine erythroid progenitors. Regulation of the adhesive properties during erythroid differentiation may alter the ability of progenitors to migrate in the bone marrow and thus play an important role in normal murine erythroid differentiation.
Telomerase Regulation, Cell Cycle, and Telomere Stability in Primitive Hematopoietic Cells
Authors: Engelhardt Monika , Kumar Rakesh , Albanell Juan , Pettengell Ruth , Han Wei , Moore Malcolm A.S.
Published: October 2019

Low levels of telomerase activity have recently been detected in human primitive hematopoietic cells, however, blood cells exhibit telomere shortening on cell proliferation. This challenging observation led us to study telomerase regulation and telomere length in human hematopoietic progenitor cells from fetal liver (FL), cord blood (CB), peripheral blood (PB), and bone marrow (BM). We found telomerase activity in CD34+/CD38+ cells exceeding levels in CD34+/CD38−, CD34−, and mononuclear cells (P < .05). Baseline telomerase activity was highest in BM (n = 5) CD34+ cells, followed by PB (n = 20), CB (n = 11), and FL (n = 1). Within 48 hours to 72 hours of in vitro culture of CD34+ cells in the presence of cytokines (KL, interleukin-3 [IL-3], IL-6, erythropoietin, granulocyte colony-stimulating factor), telomerase activity was upregulated, peaked after 1 week of culture, and decreased to baseline levels or below detection after 3 to 4 weeks. Stimulation of CD34+ cells with single cytokines resulted in no or minor telomerase upregulation, whereas cytokine combinations resulted in a significant telomerase increase (P < .001). There was a correlation between telomerase activity, cell cycle status by BrdU incorporation, and induction of phosphorylated retinoblastoma protein, CDC2, CDK2, cyclin D1, and cyclin A, but not cyclin E and B1 after 72 hours with multiple (but not single) cytokines. In nonexpanding CD34+ cells, telomerase was low or undetectable. Secondary CD34+ cells showed a reduced ability to upregulate telomerase activity. Antiproliferative cytokines such as transforming growth factor-β1 and high concentrations of all-trans–retinoic acid in cytokine-supported CD34+ cultures downmodulated telomerase activity. Average telomere lengths were 10.4 kbp, 7.4 kbp, and 7.6 kbp in CB, PB, and BM CD34+ cells, respectively. In ex vivo expansion cultures, an average telomeric DNA loss of 1 to 2 kbp over 4 weeks was observed. However, the rate of base pair loss per population doubling was significantly lower during the first 2 weeks, when telomerase was upregulated, than during weeks 3 and 4 of culture. In summary, telomerase is upregulated in response to cytokine-induced proliferation and cell cycle activation in primitive hematopoietic cells. Telomerase is downregulated between weeks 3 and 4 of ex vivo expansion culture linked with decreased proliferation and greater expansion of more mature cell subsets. Our data suggest that telomerase activity in hematopoietic cells reduces, but does not prevent, telomere shortening on proliferation.
Interleukin-6 Overcomes p21WAF1 Upregulation and G1 Growth Arrest Induced by Dexamethasone and Interferon-γ in Multiple Myeloma Cells
Authors: Urashima Mitsuyoshi , Teoh Gerrard , Chauhan Dharminder , Hoshi Yasutaka , Ogata Atsushi , Treon Steven P. , Schlossman Robert L. , Anderson Kenneth C.
Published: October 2019

Interleukin-6 (IL-6) is a growth factor for multiple myeloma (MM) cells and can inhibit MM cell apoptosis. Our recent studies show that IL-6 facilitates MM cell growth via phosphorylation of retinoblastoma protein (pRB); however, the effects of IL-6 on those cyclins, cyclin-dependent kinases (CDKs), and CDK inhibitors (CDIs) that are known to regulate phosphorylation of pRB have not been defined in MM cells. In the present report, we cultured MM cell lines and patient cells with IL-6 and/or dexamethasone (Dex) and characterized changes in cell cycle; expression and association of cyclins, CDKs, and CDIs; and phosphorylation of pRB. Dex induced G1 growth arrest in MM cells, whereas IL-6 facilitated G1 to S phase transition; moreover, the effect of Dex was blocked by IL-6. p21WAF1 (p21) protein was constitutively expressed in the majority of MM cells independent of the status of p53. Its expression was upregulated by Dex and downregulated by IL-6; again, IL-6 inhibited the increase in p21 triggered by Dex. These alterations in p21 expression in MM cells were associated with changes in p21 binding to CDK2, CDK4, and CDK6; CDK2, CDK4, and CDK6 kinase activities; and phosphorylation of pRB. In contrast, expression of G1 cell cycle regulatory proteins, including p27KIP1, cyclin D2, and cyclin E, was not altered in MM cells cultured with Dex and/or IL-6. Finally, interferon-γ (IFN-γ) also induced G1 growth arrest and upregulated p21 protein expression; as with Dex, affects of IFN-γ were inhibited by IL-6. Our results therefore show that changes in cell cycle distribution in MM cells triggered by Dex, IL-6, and IFN-γ correlate with changes in p21 protein expression and implicate p21 in the coupling of Dex-, IL-6–, and IFN-γ–related signals to G1 cell cycle regulation in MM cells.
HLA-DR1–Restricted bcr-abl (b3a2)-Specific CD4+ T Lymphocytes Respond to Dendritic Cells Pulsed With b3a2 Peptide and Antigen-Presenting Cells Exposed to b3a2 Containing Cell Lysates
Authors: Mannering S.I. , McKenzie J.L. , Fearnley D.B. , Hart D.N.J.
Published: October 2019

Chronic myeloid leukemia (CML) is characterized by a specific translocation of the c-abl oncogene on chromosome 9 to the break point cluster region (bcr) on chromosome 22, t(9; 22) (q34; q11). This translocation results in the expression of a 210-kD bcr-abl protein fusion gene product. The juxtaposition of the bcr and abl genes produces a novel junctional amino acid sequence, which may be presented by antigen-presenting cells and recognized specifically by human T lymphocytes. We have generated a CD4+ T lymphocyte line (NG-1) which recognizes the peptide epitope (GFKQSSKALQR) in association with HLA-DRβ1*0101-02. A comparison of antigen-presenting cells showed that CMRF-44+ blood dendritic cell presented a 12mer b3a2 peptide effectively. The b3a2 peptide was able to generate specific primary T-lymphocyte responses in other HLA-DR1 donors. We also show that bcr-abl, b3a2 peptide-specific T-lymphocyte lines proliferate in response to bcr-abl b3a2 containing cell lysates (K562 or CML PBMC derived) but not control (including b2a2 CML PBMC) lysates.
Antisense Oligodeoxyribonucleotides Suppress Hematologic Cell Growth Through Stepwise Release of Deoxyribonucleotides
Authors: Vaerman J.L. , Moureau P. , Deldime F. , Lewalle P. , Lammineur C. , Morschhauser F. , Martiat P.
Published: October 2019

Antisense oligodeoxyribonucleotides (ODNs) are now being extensively investigated in an attempt to achieve cell growth suppression through specific targeting of genes related to cell proliferation, despite increasing evidence of non-antisense cytotoxic effects. In the context of anti-BCR/ABL antisense strategies in chronic myeloid leukemia, we have re-examined the antiproliferative effect of phosphodiester and phosphorothioate ODNs on the leukemic cell line BV173 and on CD34+ bone marrow cells in liquid culture. The 3′ sequences of the ODNs determine their effect. At concentrations of 10 μmol/L (for phosphorothioate ODNs) or 25 μmol/L (for phosphodiester ODNs), all the tested ODNs exert an antiproliferative activity, except those that contain a cytosine residue at either their two most terminal 3′ positions. We show that this antiproliferative effect is due to the toxicity of the d-NMPs (5′ monophosphate deoxyribonucleosides), the enzymatic hydrolysis products of the ODNs in culture medium. The toxicity of the d-NMPs on hematologic cells depends on their nature (d-CMP [2′deoxycytidine 5′-monophosphate] is not cytotoxic), on their concentration (d-GMP [2′-deoxyguanosine 5′-monophosphate], TMP [thymidine 5′-monophosphate], and d-AMP [2′-deoxyadenosine 5′-monophosphate] are cytotoxic at concentrations between 5 and 10 μmol/L), and on the coincident presence of other d-NMPs in the culture medium (d-CMP neutralizes the toxicity of d-AMP, d-GMP, or TMP). The antiproliferative activity of ODNs is thus restricted to conditions where the 3′ hydrolysis process by exonucleases generates significant amounts of d-NMPs with a low proportion of d-CMP. Our results reveal a novel example of a nonantisense effect of ODNs, which should be taken into account when performing any experiment using assumed antisense ODNs.
Circulating Blood B Cells in Multiple Myeloma: Analysis and Relationship to Circulating Clonal Cells and Clinical Parameters in a Cohort of Patients Entered on the Eastern Cooperative Oncology Group Phase III E9486 Clinical Trial
Authors: Kay Neil E. , Leong Traci , Kyle Robert A. , Greipp Philip , Billadeau Daniel , Van Ness Brian , Bone Nancy , Oken Martin M.
Published: October 2019

Recent analyses of circulating blood B cells in myeloma have generated controversy concerning the exact levels of these cells and whether they may represent circulating clonal tumor B cells. Previous reports suggested that CD19+ B cells are markedly increased in myeloma patients and that this population shares clonotypic rearrangements with the malignant plasma cell. We studied the numbers of CD19+ B cells by flow cytometry in previously untreated newly diagnosed myeloma patients in Eastern Cooperative Oncology Group (ECOG) phase III trial E9486. There were 628 patients who were eligible for the clinical protocol E9486, but of these 521 were also entered on the companion laboratory study (E9487) and had CD19 data. In comparison with normal controls, the myeloma patients exhibited a marked heterogeneity in the number of circulating CD19+ B cells as detected by flow cytometry. Approximately 20% of patients had significantly increased levels of circulating CD19+ B cells. However, the total CD19+ blood population from myeloma was not significantly different from the median of age-matched, normal controls. Analysis of CD19+ blood cells in relationship to circulating clonal cells was done in 13 myeloma patients using a clonotypic, quantitative allele-specific oligonucleotide-polymerase chain reaction (PCR) assay. No correlation was found between the numbers of CD19+ B cells (range, 5% to 51%) and PCR estimates of the number of clonal cells in the peripheral blood (range, .009% to 3.6%). Low CD19+ B-cell level (<125 μL) was associated with clinical stage III (P = .033). A significant relationship exists between higher levels (≥125/μL) of CD19 cells and longer overall survival (P < .0001). In addition, high CD19 levels also predicted a clinical response and longer event-free survival. There was a strong inverse association between the level of CD19 values at diagnosis and infections within the first 2 months of diagnosis. Importantly, the number of deaths related to infections was significantly greater in the low versus high CD19 group (P < .0202). Also, CD19 is an independent prognostic factor in addition to plasma cell labeling indices, β2 -microglobulin, hemoglobin, and plasmablastic morphology. Patients with infections were more likely to have low levels of CD19+ cells. In summary, higher CD19+ cell levels are a favorable prognostic sign with no apparent relationship to circulating tumor cells. In addition, this analysis strongly suggests that low peripheral blood levels of CD19+ cells are an adverse prognostic sign in myeloma. The CD19+ cell levels in myeloma patients is an important parameter in the overall assessment of these patients.