bluuebunny/crossref_metadata_2025 huggingface dataset:
Anti-IgM induces transforming growth factor-beta sensitivity in a human B-lymphoma cell line: inhibition of growth is associated with a downregulation of mutant p53
Authors: Beckwith M , Ruscetti FW , Sing GK , Urba WJ , Longo DL
Published: October 2019

We wished to examine the role of transforming growth factor-beta (TGF-beta) in the regulation of human lymphoma cell growth. The RL cell line is an immunoglobulin M (IgM)+, IgD+ B lymphoma cell line, which does not constitutively express receptors for TGF-beta, and thus has lost the ability to respond to the inhibitory effects of TGF-beta. We demonstrate here that anti-Ig antibodies can efficiently upregulate the expression of TGF-beta receptors and promote sensitivity to growth inhibition by TGF-beta. Furthermore, because TGF-beta has been shown to function in late G1 of the cell cycle, we examined the ability of TGF-beta to modulate two tumor suppressor proteins known to be critical regulators of the G1/S transition, Rb and p53. Rb is a 105- to 110-kD phosphoprotein, which has been shown to maintain its growth suppressive function when it is found in the hypophosphorylated state. Wild-type p53 is a 53-kD phosphoprotein that appears to be important in preventing cell-cycle progression and promoting apoptosis in cells with DNA damage, whereas mutant p53 can overcome those functions. We show here that TGF-beta treatment of phorbol myristate acetate (PMA) or anti-Ig-activated RL cells results in growth inhibition through a dual effect on Rb and mutant p53. After TGF-beta treatment, we observe a predominance of Rb in the hypophosphorylated, growth suppressive form. In addition, we show a decrease in levels of mRNA and protein for mutant p53. We also show that, although these changes are sufficient to halt progression through the cell cycle, the cells do not appear to undergo extensive programmed cell death following 72 hours of TGF-beta treatment. Thus, although these lymphoma cells maintain the capacity to be negatively growth regulated by TGF-beta, the ability of TGF-beta to induce apoptosis must be independently controlled.
Marrow- and spleen-seeding efficiencies of all murine hematopoietic stem cell subsets are decreased by preincubation with hematopoietic growth factors
Authors: van der Loo JC , Ploemacher RE
Published: October 2019

The cobblestone-area forming cell (CAFC) assay permits a direct measurement of the seeding of primitive and more mature murine hematopoietic stem cell subsets by comparing the number of CAFC in the original transplant with the number of CAFC retrieved from bone marrow (BM) and spleen after transplantation. We found no differences in seeding efficiency between the more mature and primitive CAFC subsets, nor between seeding efficiencies of stem cells from low-density (LD) fractions of normal and day-6 post-5-fluorouracil BM. The data show that 18% to 20% of all intravenously transplanted stem cell subsets seed to the BM, whereas 8% to 10% seed to the spleen. In addition, similar seeding efficiencies were found for day-12 spleen colony-forming unit (CFU-S-12) as was determined by retransplantation. Previously, it has been reported that a 2- to 3-hour preincubation of BM with interleukin-3 (IL-3) enhances the in vivo repopulating ability of a graft. To test whether hematopoietic growth factors affected this increased engraftment by enhancing the seeding of the transplanted marrow, we assessed the 16- to 18-hour seeding efficiency of short- and long-term in vivo repopulating stem cell subsets to BM and spleen using the CAFC assay, after preincubation with or without hematopoietic growth factors. A 2- to 3-hour preincubation with IL-3, or a combination of IL-3, IL-12, and steel factor, at 37 degrees C, led to a substantial decrease in seeding compared with control (which was kept on ice) of all hematopoietic subsets measured, both in spleen and BM. In concert with these data, the long-term in vivo repopulating ability of growth-factor incubated BM was also decreased when compared with control. In conclusion, we have been unable to observe a beneficial effect of growth factor preincubation on the repopulating ability of a graft.
Polymerase chain reaction detection of the BCR-ABL fusion transcript after allogeneic marrow transplantation for chronic myeloid leukemia: results and implications in 346 patients
Authors: Radich JP , Gehly G , Gooley T , Bryant E , Clift RA , Collins S , Edmands S , Kirk J , Lee A , Kessler P
Published: October 2019

We studied 346 patients after bone marrow transplantation (BMT) for chronic myeloid leukemia (CML) for the presence of the bcr-abl transcript detected by the polymerase chain reaction (PCR) to understand the frequency and implication of a positive test. A total of 634 samples of BM and/or peripheral blood were obtained for PCR analysis between 3 and 192 months after BMT. A positive PCR test at 3 months post-BMT was not statistically significantly associated with an increased risk of relapse compared with PCR-negative patients. However, a positive PCR assay at 6 months and beyond was highly associated with subsequent relapse. The Kaplan-Meier estimate of relapse for patients testing PCR-positive at 6 to 12 months was 42% versus 3% for PCR-negative patients (P < .0001). The Kaplan-Meier estimate of survival at 4 years for the PCR-positive patients was 74% compared with 83% for the PCR-negative group (P = .002). Multivariable analysis indicated that a PCR-positive result at 6 to 12 months post-BMT, the type of BMT donor (allogeneic matched donor v mismatched or unrelated), and the presence of acute GVHD were independent risk factors for subsequent relapse. The relative risk (RR) for relapse for patients PCR-positive at 6 to 12 months post-BMT was 26.1 (95% confidence interval, 8.9 to 76.1, P < .0001). The outcome of long-term patients (> 36 months post-BMT) who tested PCR-positive was much better, as 15 of 59 (25%) tested positive for bcr-abl, but only one patient relapsed. There was a 91% concordance between PCR tests of simultaneously obtained BM and peripheral blood. These analyses show that the PCR assay of the bcr-abl fusion transcript 6 to 12 months post-BMT is an independent predictor of subsequent relapse which provides an opportunity for early therapeutic intervention.
Variations in radiation sensitivity and repair among different hematopoietic stem cell subsets following fractionated irradiation
Authors: Down JD , Boudewijn A , van Os R , Thames HD , Ploemacher RE
Published: October 2019

The radiation dose-survival of various hematopoietic cell subsets in murine bone marrow (BM) was determined in the cobblestone area forming cell (CAFC) assay under conditions of single-, split-, and multiple- dose irradiation. A greater recovery in cell survival with decreasing dose per fraction, or increasing fraction number, was observed for primitive CAFC day-28 and day-35 than for CAFC day-6 and day-12 (colony- forming unit (CFU)-granulocyte macrophage and CFU-spleen day-12 equivalents). Linear quadratic (LQ) model analysis of CAFC survival data provided an estimate of the alpha/beta ratio that is an inverse index of the fractionation effect and is known to be lower for late than for acutely responding tissues. This analysis gave decreasing alpha/beta ratios with increasing primitiveness of the CAFC subset. These values were found to be comparatively low (about 4 Gy) for CAFC day-28 and day-35 and are in general agreement with previous studies on long-term repopulation in vivo. In contrast, alpha/beta ratios of CAFC day-6 and day-12 were relatively high (above 6 Gy) and are consistent with values obtained from acute marrow failure. Delayed harvesting of BM after a single dose of 6 Gy showed little evidence of proliferative repopulation over 1 week and hence the differential dose-sparing effect of fractionation among the CAFC subsets appears to be mostly attributable to the influence of sublethal damage repair. These results require a reevaluation of previous notions of marrow stem cell radiosensitivity and repair based on acute marrow lethality (LD50/30) or spleen colony (CFU-S) data, especially when applied to fractionated total body irradiation effects on long-term repopulating stem cells in a BM transplant setting.
Growth factors and stromal support generate very efficient retroviral transduction of peripheral blood CD34+ cells from Gaucher patients
Authors: Xu LC , Kluepfel-Stahl S , Blanco M , Schiffmann R , Dunbar C , Karlsson S
Published: October 2019

We have achieved high-efficiency gene transfer into nonmobilized peripheral blood (PB) CD34+ cells from patients with Gaucher's disease using a clinically acceptable retroviral supernatant transduction protocol. In our studies, bone marrow (BM) and PB CD34+ cells were transduced using a high titer (10(8) particles/mL) retroviral supernatant once a day for 4 consecutive days in the presence of interleukin-3 (IL-3), IL-6, and stem cell factor (SCF), with or without an irradiated allogeneic BM stromal layer. The growth factors alone resulted in 29% +/- 10% gene transfer of PB CD34+ clonogenic cells in contrast with 71% +/- 17% gene transfer efficiency using stroma with the growth factors; a 2.5-fold increase. The increase in gene transfer efficiency was less prominent when BM CD34+ cells were used (40% +/- 16% without and 57% +/- 8% with stroma, a 1.5-fold increase). The overall transduction efficiency of both PB and BM CD34+ cells was lower when the cells were transduced over a stromal cell layer without added growth factors. The combination of IL-3, IL-6, and SCF with stroma transduced 75% of primitive long-term culture initiating cells (PB LTC- ICs) in comparison with 34% of LTC-ICs when IL-3, IL-6, and SCF were used without stromal support. Using this clinically acceptable supernatant/cytokines/stroma transduction protocol, correction of the glucocerebrosidase (GC) deficiency in the progeny cells of PBLTC-ICs from Gaucher's-disease patients has been accomplished. Efficient transduction of the PB CD34+ cells using this transduction protocol may allow repeated delivery of “GC-corrected” hematopoietic stem and progenitor cells to Gaucher's-disease patients.
The human leukocyte integrin CD11a promoter directs expression in leukocytes of transgenic mice
Authors: Ritchie KA , Aprikian A , Gollahon KA , Hickstein DD
Published: October 2019

The human CD11a molecule is expressed specifically on lymphocytes, monocyte/macrophages, and neutrophils, in which it mediates important adhesion-related functions. We used 1.7 kb of regulatory sequences upstream from the human CD11a gene transcription start site to drive expression of a modified human CD4 reporter gene in transgenic mice. The transgene was expressed in a tissue-specific fashion on all leukocytes and paralleled endogenous mouse CD11a expression. All five founder mice expressed the transgene, providing evidence for integration site-independent expression. However, expression was not proportional to transgene copy number. These studies indicate that (1) the mutated human CD4 serves as an excellent reporter for analysis of leukocyte-specific promoters; (2) the CD11a regulatory unit used here represents a novel reagent for targeting gene expression to leukocytes; and (3) additional regulatory regions will be required for copy-number- dependent activity of CD11a regulatory sequences.
Initiation of hematopoiesis and vasculogenesis in murine yolk sac explants
Authors: Palis J , McGrath KE , Kingsley PD
Published: October 2019

The blood islands of the visceral yolk sac (VYS) are the initial sites of hematopoiesis in mammals. We have developed a yolk sac explant culture system to study the process of blood cell and endothelial cell development from extraembryonic mesoderm cells. No benzidine-positive cells or beta H1-globin mRNA expression was detected at the primitive streak or neural plate stage of development (E7.5). However, when isolated E7.5 dissected tissues were cultured for 36 to 72 hours in serum-free medium, hundreds of hemoglobin-producing cells and embryonic globin gene expression were identified in both intact yolk sac and VYS mesoderm explants. Explanted E7.5 extraembryonic mesoderm tissues thus recapitulate in vivo primitive erythropoiesis and do not require the presence of a vascular network or the VYS endoderm. Yolk sac blood islands also contain endothelial cells that arise by vasculogenesis and express flk-1. We detected flk-1 mRNA as early as the primitive streak stage of mouse embryogenesis. Culture of embryo proper and intact VYS explants, which contain both mesoderm and endoderm cells, produced capillary networks and expressed flk-1. In contrast, vascular networks were not seen when VYS mesoderm was cultured alone, although flk-1 expression was similar to that of intact VYS explants. The addition of vascular endothelial growth factor to VYS mesoderm explants did not induce vascular network formation. These results suggest that the VYS endoderm or its extracellular matrix is necessary for the coalescence of developing endothelial cells into capillary networks.
Frequent loss of heterozygosity at the TEL gene locus in acute lymphoblastic leukemia of childhood
Authors: Stegmaier K , Pendse S , Barker GF , Bray-Ward P , Ward DC , Montgomery KT , Krauter KS , Reynolds C , Sklar J , Donnelly M
Published: October 2019

TEL is a new member of the ETS family of transcription factors which is rearranged in a number of hematologic malignancies with translocations involving chromosome band 12p13. In some cases, both TEL alleles are affected, resulting in loss of wild-type TEL function in the leukemic cells. In addition, 5% of children with acute lymphoblastic leukemia (ALL) have 12p12-p13 deletions, suggesting that a tumor suppressor gene resides on 12p. These observations led us to consider whether TEL loss of function may contribute to the pathogenesis of ALL. In this report we show that the TEL gene maps between the polymorphic markers D12S89 and D12S98, and we use these flanking markers to screen paired diagnosis and remission samples from 81 children with ALL for loss of heterozygosity (LOH) at the TEL gene locus. Fifteen percent of informative patients showed TEL LOH which was not evident on cytogenetic analysis. Detailed examination of patients with LOH at this locus showed that the critically deleted region included two candidate tumor suppressor genes: TEL and KIP1, the gene encoding the cyclin- dependent kinase inhibitor p27. These studies show that LOH at the TEL locus is a frequent finding in childhood ALL.
Characterization of Thy-1 (CDw90) expression in CD34+ acute leukemia
Authors: Holden JT , Geller RB , Farhi DC , Holland HK , Stempora LL , Phillips CN , Bray RA
Published: October 2019

Thy-1 (CDw90) is a phosphatidylinositol-anchored cell surface molecule which, when coexpressed with CD34 in normal human bone marrow, identifies a population of immature cells that includes putative hematopoietic stem cells. To date, the characterization of Thy-1 expression has been confined largely to normal tissues and cell lines. In this study, we evaluated the frequency and intensity of Thy-1 expression as defined by reactivity with the anti-Thy-1 antibody 5E10 in 38 cases of CD34+ acute leukemia (21 acute myelogenous leukemia [AML], 8 chronic myelogenous leukemia [CML] in blast crisis, and 9 acute lymphoblastic leukemia [ALL]). In 34 of 38 cases (89%) the CD34+ cells lacked expression of the Thy-1 antigen. High-density Thy-1 expression was found in 1 case of CML in lymphoid blast crisis, and low- density Thy-1 expression was identified on a portion of the leukemic cells in 2 cases of AML with myelodysplastic features, and 1 case of CML in myeloid blast crisis, suggesting a possible correlation between Thy-1 expression and certain instances of stem cell disorders such as CML and AML with dysplastic features. In contrast, the dissociation of Thy-1 and CD34 expression in the majority of acute leukemias studied suggests that the development of these leukemias occurs at a later stage than the hematopoietic stem cell. Characterization of Thy-1 expression in acute leukemia may eventually provide insights into the origin of the disease. In addition, separation of leukemic blasts from normal stem cells based on Thy-1 expression may prove useful in assessing residual disease, as well as in excluding leukemic blasts from stem cell preparations destined for autologous bone marrow or peripheral stem cell transplantation.
High prevalence of nonsense, frame shift, and splice-site mutations in 16 patients with full-blown Wiskott-Aldrich syndrome
Authors: Wengler GS , Notarangelo LD , Berardelli S , Pollonni G , Mella P , Fasth A , Ugazio AG , Parolini O
Published: October 2019

Wiskott-Aldrich syndrome (WAS) is a fully penetrant X-linked recessive disorder characterized by immunodeficiency, thrombocytopenia, and severe eczema. WAS is a life-threatening disease, with a poor quality of life and high mortality rate in childhood. The gene responsible for the disease has been localized to the proximal short arm of the X- chromosome and recently isolated through positional cloning and named WAS protein (WASP). We have characterized 17 WAS families. We have developed a rapid, nonradioactive screening protocol for identifying WASP gene alterations in genomic DNA. Our method allows simultaneous evaluation of single strand confirmation polymorphism and heteroduplex formation. We have identified 15 novel mutations that involve single basepair changes, or small insertions or deletions, all of which result in premature stop cordon, frame shift with secondary premature stop codon, or splice site defect. These studies document the considerable heterogeneity of the location of mutations in the WASP gene causing full-blown WAS and show the efficiency and rapidity of a screening approach for mutation identification in WAS that will be useful for carrier detection and prenatal diagnosis.
Platelet storage for transfusion in synthetic media: further optimization of ingredients and definition of their roles
Authors: Murphy S , Shimizu T , Miripol J
Published: October 2019

Currently, most platelet concentrates (PC) are stored for transfusion at 20 degrees C to 24 degrees C in autologous plasma. There are potential advantages in replacing some of this plasma with a synthetic medium. In this study, our major goals were to define the optimal ingredients and their concentrations in such a medium and to gain insight into the mechanism by which each ingredient confers benefit. In addition, we wished to validate a new polyvinyl chloride container plasticized with di-n-decyl phthalate (DnDP) for PC storage. PC derived from donations of whole blood were stored for 7 days in autologous plasma or a basic synthetic medium (BSM) containing 15 mmol/L glucose, 21 mmol/L citrate, and physiologic concentrations of salts other than bicarbonate within either the DnDP container or a licensed polyolefin container, PL-732. Metabolic events were characterized and a panel of in vitro tests were used to monitor platelet quality as systematic changes in the BSM were made. Platelet quality was as least as good, if not better, after storage in DnDP in comparison to PL-732. pH consistently decreased to less than 6.0 because of inadequate buffering of lactic acid in BSM alone. However, pH and the in vitro tests were well maintained by either the serial addition of bicarbonate (BSM + B) or the addition of at least 15 mmol/L acetate and 10 mmol/L phosphate (BSM + AP). The benefits of BSM + AP were traced to a decrease in lactic acid production by 33% and 19% relative to plasma and BSM + B, respectively, and the vigorous oxidation of acetate (0.66 +/- 0.09 mmol/d/10(12 platelets). The rates of lactate production and acetate consumption were similar and the pH during storage correlated with difference between the two rates, suggesting that acetate oxidation has an alkalinizing effect equivalent on a molar basis to the acidifying effect of production of lactate and a hydrogen ion. When pyruvate replaced acetate, it was also metabolized vigorously (0.52 +/- 0.06 mmol/d/10(12) platelets). Its presence suppressed lactic acid production by 44% relative to BSM + B and allowed maintenance of pH and platelet quality similar to what is achieved with acetate. The results strongly suggest that the benefit from acetate (or pyruvate) is derived from its oxidation and the use of a hydrogen ion during that oxidation. For reasons that are not yet clear, the omission of phosphate resulted in pH decrease to less than 6.0 in 3 of 9 PC even with acetate present.(ABSTRACT TRUNCATED AT 400 WORDS)
Regulation of platelet activation in vitro by the c-Mpl ligand, thrombopoietin
Authors: Chen J , Herceg-Harjacek L , Groopman JE , Grabarek J
Published: October 2019

Thrombopoietin (TPO) is a recently identified growth factor that regulates megakaryocytopoiesis. Its receptor, c-Mpl, is expressed in megakaryocyte progenitors, mature megakaryocytes, and human blood platelets. We have observed that TPO treatment of human platelets resulted in tyrosine phosphorylation of several cellular proteins, including the c-Mpl receptor and the 85-kD subunit of phosphatidylinositol 3-kinase (PI3-K). TPO stimulated this tyrosine phosphorylation in a time-dependent manner, reaching a maximum in 5 minutes. The tyrosine phosphorylation of PI 3-K was dependent on the concentration of TPO and reached a maximum at concentrations between 50 and 100 ng/mL. This phosphorylation was independent of extracellular fibrinogen and ligation of the alpha IIb beta 3 integrin. In contrast, TPO, in the presence of exogenous fibrinogen, induced concentration- dependent platelet aggregation, which was blocked by the soluble c-Mpl receptor. Increasing TPO concentrations modulated the degree of the primary wave of aggregation and the lag phase, but not the slope or maximum of the secondary wave of aggregation. This secondary aggregation was controlled by the addition of apyrase, suggesting an adenosine diphosphate (ADP)-dependent mechanism. Treatment of platelets with TPO resulted in augmented binding of 125I-fibrinogen to intact platelets, with a 50% effect (EC50) occurring between 5 and 10 ng/mL. TPO-induced binding of fibrinogen to platelets was comparable in degree with that observed by stimulation with 10 mumol/L ADP. In an immobilized collagen-platelet adhesion assay, a significant increase in the attachment of TPO-stimulated platelets was observed. This effect was dependent on the concentration of TPO. At 50 ng/mL of TPO, platelet attachment to collagen increased threefold compared with the buffer control. Furthermore, the presence of fibrinogen did not significantly alter TPO augmentation of the platelet-collagen interaction. This interaction was mediated by the Arg-Gly-Asp (RGD) adhesion recognition sequence, as it was completely abolished by 100 mumol/L of the RGDS peptide. A fraction of the TPO-dependent platelet attachment to a collagen-coated surface was insensitive to treatment with prostaglandin E1. Furthermore, antibody to alpha IIb integrin partially inhibited platelet attachment to collagen, suggesting that the integrin alpha IIb beta 3 participates in this association. These data indicate that TPO might function not only as a cytokine in megakaryocyte growth and differentiation, but may also participate in direct platelet activation and modulate platelet-extracellular matrix interactions.
Granulomonocyte-associated lysosomal protein expression during in vitro expansion and differentiation of CD34+ hematopoietic progenitor cells
Authors: Scheinecker C , Strobl H , Fritsch G , Csmarits B , Krieger O , Majdic O , Knapp W
Published: October 2019

Using an in vitro expansion and differentiation system for human CD34+ cord blood (CB) progenitor cells, we analyzed the induction and expression kinetics of the granulomonocyte associated lysosomal proteins myeloperoxidase (MPO), lysozyme (LZ), lactoferrin (LF), and macrosialin (CD68). Freshly isolated CD34+ CB cells were negative for LZ and LF, and only small proportions expressed MPO (4% +/- 2%) or CD68 (3% +/- 1%). Culturing of CD34+ cells for 14 days with interleukin (IL)- 1, IL-3, IL-6, stem cell factor, granulocyte-macrophage colony- stimulating factor (GM-CSF), and G-CSF resulted in on average a 1,750- fold amplification of cell number, of which 83% +/- 7% were MPO+. Without addition of GM-CSF and G-CSF, lower increases in total cell numbers (mean, 211-fold) and lower proportions of MPO+ cells (54% +/- 11%) were observed. The proportion of MPO+ cells slightly exceeded but clearly correlated with the proportion of cells positive for the granulomonocyte associated surface molecules CD11b (Mac-1), CD15 (LeX), CD64 (Fc gamma RI) CD66, or CD89 (Fc alpha R). At day 14 MPO+ and LZ+ cells were virtually identical. However, at earlier time points during culture (days 4 and 7), single MPO+ or LZ+ cell populations were also observed, which only later acquired LZ and MPO, respectively. Maturation of cells into the neutrophilic pathway was indicated by the acquisition of MPO, followed by LZ. In contrast, maturation of cells into the monocytic pathway was indicated by the acquisition of LZ followed by MPO and CD14. CD68 was found to be expressed at day 4 by the majority of cells and was not restricted to the granulomonocytic cells, as cells with megakariocytic (CD41+) or erythroid (CD71hi) features were CD68+. LF expression was observed only in GM- plus G-CSF- supplemented cultures, in which only 26% +/- 5% of cells expressed LF by day 14.
Salicylates inhibit lipopolysaccharide-induced transcriptional activation of the tissue factor gene in human monocytic cells
Authors: Oeth P , Mackman N
Published: October 2019

Binding of plasma Factor VII/VIIa to the tissue factor (TF) receptor initiates the coagulation protease cascades. TF expression by circulating monocytes is associated with thrombotic and inflammatory complications in a variety of diseases. Transcriptional activation of the human TF gene in monocytic cells exposed to bacterial lipopolysaccharide (LPS) is mediated by binding of c-Rel/p65 heterodimers to a kappa B site in the TF promoter. Here, we report that a family of anti-inflammatory agents, known as the salicylates, inhibited LPS induction of TF activity and TF gene transcription in human monocytes and monocytic THP-1 cells at clinically relevant doses. Furthermore, sodium salicylate blocked the LPS-induced proteolytic degradation of I kappa B alpha, which prevented the nuclear translocation of c-Rel/p65 heterodimers. In contrast, two other nonsteroidal anti-inflammatory drugs, ibuprofen and indomethacin, did not inhibit LPS induction of the TF gene. These results indicated that salicylates inhibited LPS induction of TF gene transcription in monocytic cells by preventing nuclear translocation of c-Rel/p65 heterodimers. The clinical benefits of salicylates in the treatment of several diseases, including atherosclerosis and rheumatoid arthritis, may be related to their ability to reduce monocyte gene expression.
A human monoclonal antibody specific for the leucine-33 (P1A1, HPA-1a) form of platelet glycoprotein IIIa from a V gene phage display library
Authors: Griffin HM , Ouwehand WH
Published: October 2019

IgG alloantibodies to polymorphic platelet glycoproteins (GPs) are known to be responsible for severe thrombocytopenia in the neonate and after transfusion. Platelet GPIIIa can have either a leucine or a proline at residue 33. The most immunogenic platelet alloantigen in thrombocytopenia is the leucine 33 form of GPIIIa. Here, we have generated human monoclonal antibody fragments that are specific for the leucine and not the proline form of GPIIIa and can inhibit the binding of polyclonal human IgG alloantibodies to GPIIIa leucine 33 on platelets. The antibody fragments were selected from a library of single chain Fv fragments displayed on the surface of filamentous phage. The VH gene repertoire was derived from the peripheral blood lymphocytes of an alloimmunized individual and recombined with a VL gene repertoire from a nonimmune source. Antibodies such as these, which are able to distinguish between two variant forms of a native antigen and which have been unobtainable by conventional hybridoma technology, have both diagnostic and potential therapeutic applications.
Recombinant human erythropoietin in the anemia associated with multiple myeloma or non-Hodgkin's lymphoma: dose finding and identification of predictors of response
Authors: Cazzola M , Messinger D , Battistel V , Bron D , Cimino R , Enller-Ziegler L , Essers U , Greil R , Grossi A , Jager G
Published: October 2019

Previous phase I-II clinical trials have shown that recombinant human erythropoietin (rHuEpo) can ameliorate anemia in a portion of patients with multiple myeloma (MM) and non-Hodgkin's lymphoma (NHL). Therefore, we performed a randomized controlled multicenter study to define the optimal initial dosage and to identify predictors of response to rHuEpo. A total of 146 patients who had hemoglobin (Hb) levels < or = 11 g/dL and who had no need for transfusion at the time of enrollment entered this trial. Patients were randomized to receive 1,000 U (n = 31), 2,000 U (n = 29), 5,000 U (n = 31), or 10,000 U (n = 26) of rHuEpo daily subcutaneously for 8 weeks or to receive no therapy (n = 29). Of the patients, 84 suffered from MM and 62 from low- to intermediate- grade NHL, including chronic lymphocytic leukemia; 116 of 146 (79%) received chemotherapy during the study. The mean baseline Hb level was 9.4 +/- 1.0 g/dL. The median serum Epo level was 32 mU/mL, and endogenous Epo production was found to be defective in 77% of the patients, as judged by a value for the ratio of observed-to-predicted serum Epo levels (O/P ratio) of < or = 0.9. An intention-to-treat analysis was performed to evaluate treatment efficacy. The median average increase in Hb levels per week was 0.04 g/dL in the control group and -0.04 (P = .57), 0.22 (P = .05), 0.43 (P = .01), and 0.58 (P = .0001) g/dL in the 1,000 U, 2,000 U, 5,000 U, and 10,000 U groups, respectively (P values versus control). The probability of response (delta Hb > or = 2 g/dL) increased steadily and, after 8 weeks, reached 31% (2,000 U), 61% (5,000 U), and 62% (10,000 U), respectively. Regression analysis using Cox's proportional hazard model and classification and regression tree analysis showed that serum Epo levels and the O/P ratio were the most important factors predicting response in patients receiving 5,000 or 10,000 U. Approximately three quarters of patients presenting with Epo levels inappropriately low for the degree of anemia responded to rHuEpo, whereas only one quarter of those with adequate Epo levels did so. Classification and regression tree analysis also showed that doses of 2,000 U daily were effective in patients with an average platelet count greater than 150 x 10(9)/L. About 50% of these patients are expected to respond to rHuEpo. Thus, rHuEpo was safe and effective in ameliorating the anemia of MM and NHL patients who showed defective endogenous Epo production. From a practical point of view, we conclude that the decision to use rHuEpo in an individual anemic patient with MM or NHL should be based on serum Epo levels, whereas the choice of the initial dosage should be based on residual marrow function.
Distinction between gamma c detection and function in YT lymphoid cells and in the granulocyte-macrophage colony-stimulating factor-responsive human myeloid cell line, Tf-1
Authors: Farner NL , Voss SD , Leary TP , Gan J , Hakimi J , Evans G , Ju G , Sondel PM
Published: October 2019

Peripheral blood monocytes respond to interleukin-2 (lL-2) and express the gamma common (gamma c) subunit of the lL-2 receptor (lL-2R) complex. However, the role of lL-2 in myeloid development has recently become of interest for several reasons, including the effect gamma c mutations may or may not have on myeloid development in patients with XSCID. Many studies of lL-2 function in the myeloid cell lineage have been performed on a murine background. To study gamma c expression and function in human myeloid precursors, we introduced the human myelomonocytic cell line, Tf-1, with a retroviral vector containing the human lL-2R beta subunit to create functional human intermediate lL-2R consisting of beta gamma c dimers. We have characterized this transfected variant of Tf-1 (Tf-1 beta) with regard to its response to lL-2. Unlike the parental Tf-1 cell line that is deficient in both lL- 2R alpha and lL-2R beta expression, the Tf-1 beta transfectant binds and responds to lL-2 through intermediate-affinity lL-2Rs. Scatchard analyses indicate the number of intermediate-affinity receptors on Tf-1 beta is similar to the number found on the well-characterized YT cell line. However, detection of gamma c on Tf-1 beta cells is dramatically less than on YT cells by Western blot analysis and is undetectable by flow cytometric studies and surface iodinations. The gamma c component on YT cells is readily detected by all three methods. We conclude from these studies that the intermediate-affinity lL-2Rs on the Tf-1 cell line behave differently than those on YT cells with respect to gamma c detection. Either the gamma c molecule itself is different, or the cellular environment in which it functions is altered. Elucidation of gamma c function on this cell line will allow for its use as a model in which other cytokines using gamma c (including lL-2, lL-4, and lL-15) can be studied on the same cellular background.
Mutations in the PIG-A gene causing paroxysmal nocturnal hemoglobinuria are mainly of the frameshift type
Authors: Nafa K , Mason PJ , Hillmen P , Luzzatto L , Bessler M
Published: October 2019

Paroxysmal nocturnal hemoglobinuria is an acquired hemolytic anemia associated with somatic mutations in the X-linked gene PIG-A, which encodes a protein involved in the biosynthesis of glycosyl phosphatidylinositol anchors. To further elucidate the molecular basis of paroxysmal nocturnal hemoglobinuria, we have worked out a systematic and relatively rapid methodology to scan for mutations in the entire coding region of the PIG-A gene. By this methodology, we have identified 15 different somatic mutations in 12 patients. The mutations were spread throughout the entire PIG-A-coding region. Of the mutations, 10 caused frameshifts, 6 caused small deletions, 3 caused small insertions, and 1 caused deletion-insertion. Five single base pair substitutions caused three missense mutations, one nonsense mutation, and one defect in the donor splice site of intron 4. In each of 3 patients, two independent mutations were identified. The predominance of frameshift mutations may reflect selection for somatic mutations giving rise to clones with a completely nonfunctional PIG-A protein.
A controlled comparison of the efficacy of hetastarch and pentastarch in granulocyte collections by centrifugal leukapheresis
Authors: Lee JH , Leitman SF , Klein HG
Published: October 2019

Compared with hetastarch (HS), the low molecular weight analog pentastarch (PS) has been reported to be equally effective for granulocyte collection by centrifugal leukapheresis, to result in fewer adverse donor reactions (ADR), and to have a more rapid elimination profile. We prospectively compared the granulocyte collection efficiency (GCE), granulocyte yield, and ADR in 72 randomly paired granulocytapheresis procedures from 36 volunteer donors using the model CS-3000 Plus Blood Cell Separator (CS) and either PS or HS as the sedimenting agent. Paired collections from each donor allowed us to compare the two agents directly while controlling for intrinsic donor differences. In 33 of 36 (92%) donors, HS procedures were significantly more efficient than PS procedures (P < .001). As an average, HS collections yielded 2.3 +/- 0.67 x 10(10) granulocytes at 58% +/- 8.8% GCE, whereas PS procedures resulted in 1.4 +/- 0.76 x 10(10) granulocytes at 33% +/- 15% GCE. No starch-induced ADR were seen with either agent. For granulocyte harvests using the CS, (1) in most donors, using HS as the red blood cell sedimenting agent during centrifugal leukapheresis results in significantly higher (nearly twofold) GCE and larger granulocyte yields in comparison with using PS, (2) ADR were not observed with either agent, and (3) the potential benefit of more rapid PS elimination should be balanced against significantly lower granulocyte yields.
Primordial germ cells are capable of producing cells of the hematopoietic system in vitro
Authors: Rich IN
Published: October 2019

The identity of the cells giving rise to the hematopoietic system in the mouse embryo are unknown. The results presented here strongly suggest that hematopoietic cells are derived from a nonhematopoietic cell population that has been previously thought to give rise to the germ cells. These cells are called primordial germ cells (PGCs) and can be recognized as large cells showing blebbing and pseudopodial extrusions on their surface. They are alkaline phosphatase (AP) positive and possess a stage-specific embryonic antigen (SSEA-1) on their surface. They represent a small pool of cells in the extraembryonic mesoderm at the base of the allantois in late day-6 embryos. Primordial germ cells from 7.5- and 8.5-day visceral yolk sac and embryo proper form AP+ and SSEA-1+ colonies within 5 days when grown on an embryonic fibroblast feeder cell layer in the presence of leukemia inhibitory factor (LIF), stem cell factor (SCF), and interleukin-3 (IL-3). Individual colonies taken from day-5 cultures can be shown to differentiate into erythroid lineage cells in secondary methyl cellulose culture and produce secondary and tertiary PGCs in the presence of LIF, SCF, and IL-3. Cells taken from the region of the allantois and primitive streak can form colonies on hydrophilic Teflon (DuPont, Wilmington, DE) foils precoated with collagen and fibronectin. The cells from these colonies were then shown to form cobblestone areas on irradiated adult bone marrow stromal layers, indicating that the most primitive in vitro hematopoietic stem cell, the cobblestone-area forming cell (CAFC), was present. PGC colonies were grown in methyl cellulose in the presence of LIF, SCF, and IL-3 for 5 days, and the colonies were removed and passaged 3 times on pretreated extracellular matrix hydrophilic Teflon foils. After each passage, the cells were assayed for their differentiation capacity and PGC content. After the last passage, the number of CAFCs was also determined. It was found that, under these conditions, the PGC population expanded more than 400- fold and also contained CAFCs. It is postulated that the PGC represents a totipotent stem cell population capable of producing a variety of different cell types including cells of the hematopoietic system.
Substance P (SP) mediates production of stem cell factor and interleukin-1 in bone marrow stroma: potential autoregulatory role for these cytokines in SP receptor expression and induction
Authors: Rameshwar P , Gascon P
Published: October 2019

Substance P (SP) is a neuropeptide widely distributed in the nervous system. Its release within the bone marrow (BM) can mediate bidirectional neurohematopoietic communication via specific receptors: neurokinin-1R (NK-1R), NK-2R, or NK-3R. We have previously reported that SP effects on hematopoiesis are mediated by an NK-1-type receptor, the BM stroma, and growth factors. Here, we have studied the induction of stem cell factor (SCF) and interleukin-1 (IL-1) by SP in stroma. At 10(-9) mol/L SP, cytokine levels in supernatants were IL-1 alpha, 20 +/- 5 ng/mL; IL-1 beta, 40 +/- 10 ng/mL; and SCF, nondetectable; and the cell-associated levels were SCF, 21 +/- 2 ng/mL; IL-1 alpha, 90 +/- 6 ng/mL; and IL-1 beta, 45 +/- 3 ng/mL. Reverse transcriptase-polymerase chain reaction and ligand-binding studies with stroma stimulated by these two cytokines resulted in (1) NK-1-like receptor mRNA accumulation and (2) downregulation of SP binding sites (day 1) followed by an upregulation (day 3). Low numbers of high-affinity receptors were expressed by day 1 but not by day 3. The results indicate that SP induces IL-1 and SCF in stroma and that these cytokines have the potential to autoregulate NK-R.
Identification of a novel DNA sequence differentially expressed between normal human CD34+CD38hi and CD34+CD38lo marrow cells
Authors: Graf L , Torok-Storb B
Published: October 2019

We have applied the recently developed differential display method to extend the molecular characterization of the less mature CD34+CD38lo bone marrow progenitors in comparison with the CD34+CD38hi cells to better understand their functional differences. Immunomagnetic enrichment of CD34+ cells followed by flow cytometry was used to isolate CD34+CD38lo and CD34+CD38hi cells from human organ donor bone marrow. A limited set of the poly A+ RNA sequences present in these two cell populations was amplified by a combination of reverse transcription with an anchored oligo dT-based primer and polymerase chain reaction with the same oligo dT primer and arbitrary decamers. A radioactive tracer allowed these sequences to be displayed as a series of bands on a denaturing polyacrylamide gel. Eight bands were chosen that appeared in multiple displays to represent gene sequences differentially expressed between CD34+CD38hi and CD34+CD38lo cells. Comparison of the sequences with public DNA sequence databases available identified one sequence as myeloperoxidase. Two other clones matched sequence fragments of unknown function, whereas the remaining five are novel sequences not present in existing databases. The relative level of expression of all of the sequences was tested by an independent reverse transcriptase-polymerase chain reaction with sequence-specific oligonucleotide primers. The lower level of myeloperoxidase mRNA in CD34+CD38lo cells was confirmed, as was the higher expression of the novel sequence 345. Sequence 345 expression is highest in CD34+CD38- cells and decreases with increased CD38 expression. It is expressed in negligible amounts in hematopoietic cell lines and other sources of human tissue, suggesting it may have a functional role in normal hematopoiesis.
Biologic effects of anti-interleukin-6 murine monoclonal antibody in advanced multiple myeloma
Authors: Bataille R , Barlogie B , Lu ZY , Rossi JF , Lavabre-Bertrand T , Beck T , Wijdenes J , Brochier J , Klein B
Published: October 2019

In patients with advanced multiple myeloma (MM) there is an excess of production of interleukin-6 (IL-6) in vivo, and elevated serum levels are associated with plasmablastic proliferative activity and short survival. These data prompted us to perform a clinical trial with a murine anti-IL-6 monoclonal antibody (MoAb) to neutralize the excess of this putatively deleterious factor in these patients. Ten MM patients with extramedullary involvement frequently were treated with anti-IL-6 MoAb. The MoAb was administered intravenously to 9 patients; 1 patient with malignant pleural effusion received intrapleural therapy. Of the 3 patients who succumbed to progressive MM after less than 1 week of treatment (including the only 1 treated locally), 2 with evaluable data exhibited marked inhibition of plasmablastic proliferation. Among the 7 patients remaining more homogeneous receiving the anti-IL-6 MoAb for more than 1 week, 3 had objective antiproliferative effect marked by a significant reduction of the myeloma cell labelling index within the bone marrow. One of these 3 patients achieved a 30% regression of tumor mass. However, none of the patients studied achieved remission or improved outcome as judged by standard clinical criteria. Of major interest, objective antiproliferative effects were associated with complete inhibition of C-reactive protein (CRP) synthesis and low daily IL-6 production in vivo. On the other hand, the lack of effect in 4 patients was associated with a higher IL-6 production and inability of the MoAb to neutralize it. Anti-IL-6 was also associated with resolution of low-grade fever in all the patients and with worsening thrombocytopenia and mild neutropenia. The generation of human antibodies to Fc fragment of the murine anti-IL-6 MoAb observed in 1 patient was associated with dramatic progression. These data show that anti-IL-6 MoAb can suppress the proliferation of myeloma cells and underscore the biologic role of IL-6 for myeloma growth in vivo. Furthermore, suppression of CRP and worsening of neutropenia/thrombocytopenia both indicate that IL-6 is critically involved in acute-phase responses and granulopoiesis/thrombopoiesis.
Phosphatidylinositol-3 kinase activity is regulated by BCR/ABL and is required for the growth of Philadelphia chromosome-positive cells
Authors: Skorski T , Kanakaraj P , Nieborowska-Skorska M , Ratajczak MZ , Wen SC , Zon G , Gewirtz AM , Perussia B , Calabretta B
Published: October 2019

The BCR/ABL oncogenic tyrosine kinase is responsible for initiating and maintaining the leukemic phenotype of Philadelphia chromosome (Ph1)- positive cells. Phosphatidylinositol-3 (PI-3) kinase is known to interact with and be activated by receptor and nonreceptor tyrosine kinases. We investigated whether PI-3 kinase associates with and/or is regulated by BCR/ABL, whether this interaction is functionally significant for Ph1 cell proliferation, and, if so, whether inhibition of PI-3 kinase activity can be exploited to eliminate Ph1-positive cells from bone marrow. We show that the p85 alpha subunit of PI-3 kinase associates with BCR/ABL and that transient expression of BCR/ABL in fibroblasts and down-regulation of BCR/ABL expression using antisense oligodeoxynucleotides (ODNs) in Ph1 cells activates and inhibits, respectively, PI-3 kinase enzymatic activity. The use of specific ODNs or antisense constructs to downregulate p85 alpha expression showed a requirement for p85 alpha subunit in the proliferation of BCR/ABL-dependent cell lines and chronic myelogenous leukemia (CML) primary cells. Similarly, wortmannin, a specific inhibitor of the enzymatic activity of the p110 subunit of PI-3 kinase, inhibited growth of these cells. The growth of normal bone marrow and erythromyeloid, but not megakaryocyte, progenitors was inhibited by p85 alpha antisense [S]ODNs, but wortmannin, at the concentrations tested, did not affect normal hematopoiesis. The proliferation of two BCR/ABL- and growth factor-independent cell lines was not affected by downregulation of the expression of the p85 alpha subunit or inhibition of p110 enzymatic activity, confirming the specificity of the observed effects on Ph1 cells. Thus, PI-3 kinase is one of the downstream effectors of BCR/ABL tyrosine kinase in CML cells. Moreover, reverse transcriptase-polymerase chain reaction performed on single colonies to detect BCR-ABL transcripts showed that wortmannin was able to eliminate selectively CML-blast crisis cells from a mixture of normal bone marrow and Ph1 cells.
Benign marrow progenitors are enriched in the CD34+/HLA-DRlo population but not in the CD34+/CD38lo population in chronic myeloid leukemia: an analysis using interphase fluorescence in situ hybridization
Authors: Kirk JA , Reems JA , Roecklein BA , Van Devanter DR , Bryant EM , Radich J , Edmands S , Lee A , Torok-Storb B
Published: October 2019

Fluorescence in situ hybridization (FISH) was used to discriminate between benign and malignant cells in sorted populations of chronic myelogenous leukemia (CML) marrow. FISH has the advantage of allowing for a cell by cell analysis of the breakpoint cluster region (BCR) gene rearrangement immediately after flow sorting in nondividing G0/G1 cells that are potentially transcriptionally inactive. We initially selected CD34+ cells with very low expression of the activation antigen CD38 as a candidate phenotype for an immature and hypothetically more benign cell population, but found no enrichment for Ph negativity in that subtype. In five CML samples, 55% +/- 3.3% (mean +/- SE) of CD34+/CD38hi cells had the BCR gene rearrangement, similar to 57% +/- 3.7% seen in the CD34+/CD38lo population. In contrast, subsequent experiments (n = 4) determined that the CD34+/HLA-DRlo population in CML marrow does contain an increased proportion of benign cells: 15% +/- 1% of the CD34+/DRlo cells were BCR rearranged, compared with 52% +/- 5.8% of the CD34+/DRhi cells (P = .001). Our results indicate that benign progenitors in CML are enriched within the CD34+ cells with low DR antigen expression, but not low CD38 expression. One possible interpretation of these observations is that low CD38 antigen expression is not as useful as low HLA-DR expression for isolating immature cells.