High levels of granulocyte and granulocyte-macrophage colony-stimulating factors in cord blood of normal full-term neonates

Modulatory activity of adenosine on the immune response in cord and adult blood

BACKGROUND

Neonatal sepsis is a leading cause of neonatal morbidity and mortality, associated with immunosuppression. Myeloid-derived suppressor cells (MDSCs) are cells with immunosuppressive activity, present in high amounts in cord blood. Mechanisms regulating MDSC expansion are incompletely understood. Adenosine is a metabolite with immunoregulatory effects that are elevated in cord blood.

METHODS

Impact of adenosine on peripheral and cord blood mononuclear cells (PBMCs and CBMCs) was analysed by quantification of ectonucleotidases and adenosine receptor expression, MDSC induction from PBMCs and CBMCs, their suppressive capacity on T cell proliferation and effector enzyme expression by flow cytometry.

RESULTS

Cord blood monocytes mainly expressed CD39, while cord blood T cells expressed CD73. Adenosine-induced MDSCs from PBMCs induced indoleamine-2,3-dioxygenase (IDO) expression and enhanced arginase I expression in monocytes. Concerted action of IDO and ArgI led to effective inhibition of T cell proliferation. In addition, adenosine upregulated inhibitory A₃ receptors on monocytes.

CONCLUSION

Adenosine acts by inducing MDSCs and upregulating inhibitory A₃ receptors, probably as a mode of autoregulation. Thus, adenosine contributes to immunosuppressive status and may be a target for immunomodulation during pre- and postnatal development.

IMPACT

Immune effector cells, that is, monocytes, T cells and MDSCs from cord blood express ectonucleotidases CD39 and CD73 and may thus serve as a source for adenosine as an immunomodulatory metabolite. Adenosine mediates its immunomodulatory properties in cord blood by inducing MDSCs, and by modulating the inhibitory adenosine A₃ receptor on monocytes. Adenosine upregulates expression of IDO in MDSCs and monocytes potentially contributing to their suppressive activity.

The Ontogeny of a Neutrophil: Mechanisms of Granulopoiesis and Homeostasis

Comprising the majority of leukocytes in humans, neutrophils are the first immune cells to respond to inflammatory or infectious etiologies and are crucial participants in the proper functioning of both innate and adaptive immune responses. From their initial appearance in the liver, thymus, and spleen at around the eighth week of human gestation to their generation in large numbers in the bone marrow at the end of term gestation, the differentiation of the pluripotent hematopoietic stem cell into a mature, segmented neutrophil is a highly controlled process where the transcriptional regulators C/EBP-α and C/EBP-ε play a vital role. Recent advances in neutrophil biology have clarified the life cycle of these cells and revealed striking differences between neonatal and adult neutrophils based on fetal maturation and environmental factors. Here we detail neutrophil ontogeny, granulopoiesis, and neutrophil homeostasis and highlight important differences between neonatal and adult neutrophil populations.

Age-Appropriate Functions and Dysfunctions of the Neonatal Neutrophil

Neonatal and adult neutrophils are distinctly different from one another due to well-defined and documented deficiencies in neonatal cells, including impaired functions, reduced concentrations of microbicidal proteins and enzymes necessary for pathogen destruction, and variances in cell surface receptors. Neutrophil maturation is clearly demonstrated throughout pregnancy from the earliest hematopoietic precursors in the yolk sac to the well-developed myeloid progenitor cells in the bone marrow around the seventh month of gestation. Notable deficiencies of neonatal neutrophils are generally correlated with gestational age and clinical condition, so that the least functional neutrophils are found in the youngest, sickest neonates. Interruption of normal gestation secondary to preterm birth exposes these shortcomings and places the neonate at an exceptionally high rate of infection and sepsis-related mortality. Because the fetus develops in a sterile environment, neonatal adaptive immune responses are deficient from lack of antigen exposure in utero. Newborns must therefore rely on innate immunity to protect against early infection. Neutrophils are a vital component of innate immunity since they are the first cells to respond to and defend against bacterial, viral, and fungal infections. However, notable phenotypic and functional disparities exist between neonatal and adult cells. Below is review of neutrophil ontogeny, as well as a discussion regarding known differences between preterm and term neonatal and adult neutrophils with respect to cell membrane receptors and functions. Our analysis will also explain how these variations decrease with postnatal age.

An Effective and Safe Supplement for Stem Cells Expansion Ex Vivo: Cord Blood Serum

Mesenchymal stem cells (MSCs) are potential and optimal stem cells in clinical cell therapy, and fetal bovine serum (FBS) is widely used for expansion of MSCs, despite the risks of infectious disease transmission and immunological reaction of the xenogenic origin. This study was designed to compare human four blood group cord blood serum (CBS) with FBS in culturing human placenta-derived mesenchymal stem cells (hPDMSCs), which were derived from four blood group donors. The expansion medium included: 10% FBS, 10% A-CBS, 10% B-CBS, 10% O-CBS, and 10% AB-CBS. Cumulative population doubling, generation time, fold expansion rates and differentiation capacity, cell cycle, and immunophenotype were also assessed. The results showed that fold expansion rate and cumulative population doubling of hPDMSCs significantly increased during long-term MSC expansion in CBS medium, but the generation time decreased compared with FBS. CBS might be an effective supplement for stem cells expand rapidly ex vivo. Cell cycle and differentiation assays showed that most of the hPDMSCs expanding in the presence of CBS were in stationary phase, which was the characteristic of stem cells, and they retained their ability to differentiate into chondrogenic and endothelial cells. By comparing these four blood groups of CBS, we found that there was no significant difference among different blood groups in culturing hPDMSCs, which were isolated from different blood group donors. So CBS may be an optimal replacement to avoid the risks of FBS application in expansion of stem cell for clinical cell therapy and tissue engineering.

Granulocyte colony-stimulating factor in amniotic fluid

OBJECTIVE

The purpose of this study was to determine if granulocyte colony-stimulating factor (G-CSF) is normally present in amniotic fluid and then to determine if amniotic-fluid G-CSF levels are affected by labor and intrauterine infection.

METHODS

Amniotic fluid was collected from 35 patients in 4 groups: no labor, early labor, late labor, and labor plus chorioamnionitis. G-CSF levels were measured by enzyme-linked immunosorbent assay (ELISA).

RESULTS

The mean amniotic-fluid G-CSF concentrations prior to labor were lower than during labor (0.49 +/- 0.25 ng/ml for prior to labor vs. 1.83 +/- 1.0 ng/ml for labor, P < 0.001). With chorioamnionitis, the mean levels were elevated compared with normal labor (25.0 +/- 4.8 ng/ml for chorioamnionitis vs. 1.83 +/- 1.0 ng/ml for normal labor, P < 0.0001). In early and late labor, G-CSF was higher than prior to labor (0.49 +/- 0.25 ng/ml for no labor vs. 1.48 +/- 1.0 ng/ml for early labor, P < 0.02, vs. 2.2 +/- 0.8 ng/ml for late labor, P < 0.0005). The mean concentrations in early and late labor were not different.

CONCLUSIONS

G-CSF is present in amniotic fluid and increased with labor. When labor is complicated by chorioamnionitis, G-CSF is significantly elevated.

High avidity cytokine autoantibodies in health and disease: pathogenesis and mechanisms

Numerous reports have documented the presence of autoantibodies working against naturally occurring cytokines in humans in health and disease. In most instances, their physiological and pathophysiological significance remains unknown. However, recent advances in the methodologies for detecting cytokine autoantibodies and their application in research focused on specific disorders have shown that some cytokine autoantibodies play an important role in the pathogenesis of disease. Additionally, levels of cytokine autoantibodies may also correlate with disease severity and progression in certain infectious and autoimmune diseases but not in others. This suggests that cytokine-specific pathogenic differences exist. While multiple lines of evidence support the notion that high avidity cytokine autoantibodies are present and likely to be ubiquitous in healthy individuals, their potential physiological role, if any, is less clear. It is believed that they may function by scavenging pro-inflammatory cytokines and thereby inhibiting deleterious 'endocrine' effects, or by serving as carrier proteins, providing a 'reservoir' of inactive cytokines and thus modulating cytokine bioactivity. A central hypothesis is that sustained or repeated high-level exposure to cytokines triggers defects in T-cell tolerance, resulting in the expansion of existing cytokine autoantibody-producing B cells.

Multi-nucleated giant cell formation from human cord blood monocytes in vitro, in comparison with adult peripheral blood monocytes

Multi-nucleated giant cells (MGCs; Langhans-type cell), formed from macrophage fusion, are recognized as a hallmark histological feature in chronic inflammation. However, their precise pathological role is still poorly understood, especially for microorganism pathogens in the neonatal immune system, which are capable of surviving intracellularly in phagocytes. To conduct a partial evaluation of the monocyte function of neonates, we investigated the ability of human cord blood monocytes to form MGCs in vitro by stimulating various cytokines and comparing them with adult peripheral blood monocytes. Monocytes from cord blood and adult peripheral blood were isolated and cultured for 14 days with cytokines known to induce MGC in vitro. The fusion index in experiments with a combination of interleukin (IL)-4 and macrophage colony-stimulating factor (M-CSF) and a combination of IL-4 and granulocyte-macrophage colony-stimulating factor (GM-CSF) was significantly lower in cord blood than in adult blood monocytes (P = 0.0018 and P = 0.0141, respectively). The number of nuclei per MGC was significantly lower in cord blood than in adult blood monocytes in experiments with IL-4 alone, the combination of IL-4 and M-CSF, and the combination of IL-4 and GM-CSF (P < 0.0001). These results suggest the possibility that the susceptibility of newborns to mycobacterium infection is due partly to impaired MGC formation.

Identification of CD123+ myeloid dendritic cells as an early-stage immature subset with strong tumoristatic potential

CD123 has been identified as a specific surface marker for plasmacytoid dendritic cells (PDCs). However, CD123 has recently been shown to be expressed on freshly isolated or in vitro generated myeloid dendritic cells (MDCs). In this article, we investigated whether the expression of CD123 on monocyte-derived MDCs was related to their function, especially to tumor-inhibiting potential. MDCs were induced from cord blood CD14+ monocytes with granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-4 (IL-4) for 7 days, and then CD123+ cells were isolated by positive immunomagnetic cell selection. We observed that CD123+ cells lost monocyte CD14 expression, acquired immature myeloid dendritic cell phenotype and morphology. They exerted more significant endocytosis and less antigen-presenting function than CD123(-)MDCs which are often referred to as typical MDCs. Meanwhile, CD123+ MDCs exhibited more significant tumor-inhibiting activity toward hematological tumor cell lines of U937 and Jurkat even at a low effector:target ratio. CD123+ MDCs expressed higher level of cytoplasmic TNF-alpha-related apoptosis-inducing ligand (TRAIL), but no detectable surface TRAIL and very little soluble TRAIL. Pretreatment with recombinant human TRAIL receptor 2:Fc fusion protein significantly reduced the tumor-inhibiting effect of CD123+ MDCs, but not of CD123(-) MDCs. Overall, our data demonstrated that CD123+ MDCs were an early-stage immature DC subset, with a significant tumor-inhibiting activity partially via involvement of enhanced cytoplasmic TRAIL.

Association between serum macrophage colony-stimulating factor levels and monocyte and thrombocyte counts in healthy, hypoxic, and septic term neonates

OBJECTIVE

Macrophage colony-stimulating factor (M-CSF) is a hematopoietic growth factor that mainly stimulates the growth, differentiation, and proliferation of cells of the monocyte-macrophage lineage. There are only limited numbers of studies about M-CSF levels in neonates, but high levels of serum M-CSF have been reported in septic and some thrombocytopenic adult patients. In this study, we investigated the serum M-CSF levels in healthy, septic, and hypoxic term neonates on the first day of life and examined the relationship of serum M-CSF levels and circulating monocyte and thrombocyte counts in these newborn infants.

STUDY DESIGN

Three groups were defined in this prospective study: group 1, healthy neonates with no risk factors (n = 40); group 2, neonates who had severe hypoxia (n = 20); and group 3, neonates who fulfilled the criteria for early-onset sepsis (n = 18). Blood samples were collected for complete blood cell count and serum M-CSF levels by peripheral venipuncture from each infant in the first 24 hours after birth before any medical therapy.

RESULTS

The gestational ages and birth weights did not differ significantly between the groups. Serum M-CSF levels of the septic neonates were significantly higher than of both healthy and hypoxic neonates, but did not differ significantly between the healthy and hypoxic neonates. There was no significant correlation between serum M-CSF levels and circulating monocyte counts, but there was a significant inverse correlation between serum M-CSF levels and thrombocyte counts. When this correlation was analyzed according to groups, we determined that this inverse correlation between M-CSF levels and thrombocyte counts was especially significant in the septic neonate group, but not significant in the healthy and hypoxic neonate groups.

CONCLUSIONS

Serum M-CSF levels are significantly higher in neonates with sepsis. High serum M-CSF levels may have a possible role in the pathogenesis of thrombocytopenia in neonates with sepsis.

Human developmental biology of granulocyte colony-stimulating factor

The availability of granulocyte colony-stimulating factor (G-CSF) has influenced the management of neonates with neutropenia. Since the first use of G-CSF in a neonate with neutropenia, much has been learned about the cellular sources and physiologic roles of G-CSF. This article reviews our present understanding of G-CSF and its cognate receptor in the fetus and neonate.

Granulocyte colony-stimulating factor in the cord blood of premature neonates born to mothers with pregnancy-induced hypertension

OBJECTIVES

To estimate the cord blood levels of granulocyte colony-stimulating factor (G-CSF) and granulocyte-macrophage colony-stimulating factor (GM-CSF) in preterm infants and to study the relationship of these levels to pregnancy-induced hypertension (PIH) and absolute neutrophil counts.

STUDY DESIGN

G-CSF and GM-CSF levels in the cord blood of preterm neonates (n = 74) either with or without maternal PIH were estimated by enzyme-linked immunosorbent assay.

RESULTS

Infants in the PIH group had lower white blood cell, absolute neutrophil, absolute lymphocyte, and monocyte counts. The levels of G-CSF in cord blood were significantly lower in infants whose mothers had PIH (P =.04) and in infants with neutropenia (P =. 01). G-CSF levels were positively correlated with both absolute neutrophil count (P =.02) and total white blood cell count (P =.01). GM-CSF was undetectable in all subjects. According to logistic regression with neutropenia as the dependent variable, only maternal PIH (P <.001), gestational age (P <.001), and G-CSF (P =.01) were independently related.

CONCLUSION

In this study maternal PIH and low gestational age were significantly associated with neutropenia in premature infants. Low G-CSF levels may contribute to the neutropenia that is commonly seen in infants born to mothers with PIH.

Hematopoietic growth factor levels in term and preterm infants

The problems of immunologic adaptation during the transitional period from intra- to extrauterine life are responsible for the physiologic immaturity of the immune function in newborn infants. In preterm neonates the immunodeficiency is more severe and prolonged and is associated with a higher incidence of infections and sepsis. Furthermore, due to immaturity of the hematologic system, anemia, thrombocytopenia, and neutropenia are frequently observed in very low birth weight infants. The dysregulation of cytokine and hematopoietic growth factor synthesis is an important contributory factor to the complex deficiency of immunologic and hematologic function in the neonate and may explain the reduced incidence of acute graft-versus-host disease observed after cord blood transplantation in children. Human milk is a rich source of most of the cytokines that are reduced in the neonate. Granulocyte colony-stimulating factor, granulocyte-macrophage colony-stimulating factor, and erythropoietin are currently under evaluation in newborn infants with septic neutropenia or anemia of prematurity.

Thrombopoietin (Tpo) in the fetus and neonate: Tpo concentrations in preterm and term neonates, and organ distribution of Tpo and its receptor (c-mpl) during human fetal development

Little is known about thrombopoietin (Tpo) production in human fetuses and neonates. As a step toward determining whether Tpo is relevant to platelet production in the fetus and neonate, we hypothesized that: (1) like other cytokines, Tpo is present in the cord blood in higher concentrations than in adult plasma; (2) Tpo and its receptor (c-mpl) are expressed in fetuses at, and following, 5-6 weeks post-conception (when platelet production begins); and (3) the sites of Tpo and c-mpl production in the fetus are similar to those of adults. We quantified Tpo, by ELISA, in the plasma of 50 adults, as well as in the umbilical cord plasma of 50 preterm and term infants. We also characterized, by RT-PCR, the organ distribution of Tpo and c-mpl during fetal development (at 8 and 16 weeks). Tpo concentrations were measurable (> or =41 pg/ml) in only two of the 50 adult samples (44 and 46 pg/ml), but in 24 of the 50 cord plasma samples (of the 24 samples, the median was 62 pg/ml; mean+/-SD, 80+/-39 pg/ml). Tpo levels did not correlate with either gestational age or platelet count at birth. Similarly to adults, in the fetal tissues, Tpo transcripts were found in all organs tested, but the most dense bands were from liver. C-mpl transcripts were also predominantly from liver. We conclude that: (1) Tpo is present in higher concentrations in cord plasma than in venous plasma of adults; (2) Tpo and c-mpl transcripts are detected in human fetuses as early as the onset of platelet appearance; and(3) Tpo and c-mpl have a similar organ distribution in fetuses and adults.

G-CSF, GM-CSF and IL-6 levels in cord blood: diminished increase of G-CSF and IL-6 in preterms with perinatal infection compared to term neonates

AIM

The objectives of this study were 1) to clarify the physiologic regulation of cytokines such as IL-6, G-CSF and GM-CSF in preterm and term neonates and 2) to evaluate the influence of perinatal stress and infection on endogenous cytokine levels.

METHOD

We examined cord blood levels of G-CSF, GM-CSF and IL-6 using a bioassay in 43 term and 44 preterm neonates.

RESULTS

Compared to normal neonates (G-CSF: mean (m) = 97.6 +/- 16.3 pg/ml; IL-6: m = 20.2 +/- 4.6 pg/ml), we found elevated G-CSF levels in newborns with perinatal stress (m = 247.1 +/- 72.1 pg/ml; p = 0.003) and increased levels for G-CSF (m = 8980.9 +/- 4388 pg/ml; p = 0.0003) and IL-6 (m = 705 +/- 322.3 pg/ml; p = 0.025) in neonates with infection. Term newborns with infection had higher G-CSF levels than preterms (m = 15575 +/- 9374 pg/ml versus m = 5384.1 +/- 4470.9 pg/ml; p = 0.024). G-CSF levels of newborns with infection were correlated with birth weight (r = 0.50; p = 0.024) but not with gestational age (r = 0.40; p = 0.057). GM-CSF was only detectable in cord blood in 4 cases of normal healthy neonates.

CONCLUSIONS

The response of G-CSF levels in preterms to infection is diminished. Body cell mass is more important than gestational age to provide high G-CSF levels during states of infection.

Plasma levels and gene expression of granulocyte colony-stimulating factor, tumor necrosis factor-alpha, interleukin (IL)-1beta, IL-6, IL-8, and soluble intercellular adhesion molecule-1 in neonatal early onset sepsis

Bacterial sepsis is still a leading cause of neonatal morbidity and mortality. Early onset sepsis in particular, presents with a different clinical course and involves other pathogens than sepsis later in life. In this study, plasma concentrations and mRNA expression of granulocyte colony-stimulating factor (G-CSF), tumor necrosis factor-alpha (TNF-alpha), IL-1beta, IL-6, IL-8, and soluble intercellular adhesion molecule-1 (sICAM-1) of neonates with early onset sepsis were evaluated in cord blood and during the first days of life. Irrespective of prematurity, plasma levels of G-CSF, TNF-alpha, IL-1beta, IL-6, and IL-8, but not sICAM-1, were excessively elevated in septic neonates when compared with both healthy infants and infants with clinically suspected but not confirmed sepsis. Compared with the corresponding maternal levels, neonatal cytokine cord plasma levels were likewise highly elevated, indicating the endogenous cytokine production by the neonate. With the exception of TNF-alpha, mRNA expression in blood cells from septic infants was, however, not more frequently detectable than in those from nonseptic patients. Cytokine levels decreased significantly within the first days of life, whereas levels of sICAM-1 and C-reactive protein increased during the same time period. In summary, in contrast to C-reactive protein and sICAM-1, cord blood plasma levels, but not the presence of mRNA, of G-CSF, TNF-alpha, IL-1beta, IL-6, and IL-8 can predict neonatal early onset sepsis with a high sensitivity and specificity. Cell types other than blood cells are likely to contribute considerably to the high cytokine production in septic newborns.

Biology of human umbilical cord blood-derived hematopoietic stem/progenitor cells

Reported in 1989, studies by Broxmeyer, Gluckman, and colleagues demonstrated that umbilical cord blood (UCB) is a rich source of hematopoietic stem/progenitor cells (HSPC) and that UCB could be used in clinical settings for hematopoietic cell transplantation. Since then, a great interest has been generated on the biological characterization of these cells. Over the last nine years, several groups have focused on the study of UCB HSPC, addressing different aspects, such as the frequency of these cells in UCB, the identification of different HSPC subsets based on their immunophenotype, their ability to respond to hematopoietic cytokines, the factors that control their proliferation and expansion potentials, and their capacity to reconstitute hematopoiesis in animal models. Most of these studies have shown that significant functional differences exist between HSPC from UCB and adult bone marrow (i.e., the former possess higher proliferation and expansion potential than the latter). It is also noteworthy that genetic manipulation of UCB HSPC has been achieved by several groups and that genetically modified UCB cells have already been used in the clinic. In spite of the significant advances in the characterization of these cells, we are still in the process of trying to fully understand their biology, both at the cellular and the molecular levels. In the present article, we describe and discuss what is currently known about the biology of UCB HSPC.

Potential for clinical use of viable pluripotent progenitor cells in blood bank stored human umbilical cord blood

There are indications that a close HLA match may not be necessary when human umbilical cord blood (HUCB) is used to effect a hematopoietic transplant. This was first suggested in 1972 and was further supported by the ability of HUCB to produce mouse survival following lethal irradiation. In China multiple units of HLA unmatched HUCB was utilized successfully in children to effect transplants. A recent publication indicated that newborn rodent blood cells can engraft in adult mice across the non-H-2 [corrected] antigens. Furthermore, there recently have been successful transplants with 3 antigens mismatched HUCB. In this study HUCB was stored in polyolefin blood bank bags at 4 degrees C. The storage was similar to that used in routine blood banking. Clonogenic assays were performed at Day 1 and 21 utilizing various growth factors. Replating efficiency was determined on colonies obtained from cord blood that was stored (non-frozen) for 21 days. The functional ability of day 21 old HUCB was determined by its ability to produce survival of lethally irradiated mice. It was found that approximately two-thirds (62.5%) of single primary blast cell colonies in day 21 stored HUCB could generate various types of secondary colonies. In some instances the secondary colonies were counted as high as 42 total mean colonies per single primary colony. These blast cell colonies (CFU-BL) were able to form single and multi lineage colonies composed of virtually every hematopoietic cell types. Animal survival studies were utilized in an effort to determine possible functional ability and were successful in producing fifty-day survival in 54% of lethally irradiated SJL/J mice and 100% ALB/C mice. This study holds the potential of making HUCB available for purposes of marrow transplantation to all who need it. It could further remove most of the moral and ethical issues related to HUCB, reduce to a fraction the cost in providing stem cells for marrow transplantation and potentially allow HUCB to be handled by existing blood banks.

Plasma effects on phagocytic activity and hydrogen peroxide production by polymorphonuclear leukocytes in neonates

To elucidate the defense mechanism in neonates against bacterial infections, phagocytic activity and hydrogen peroxide (H2O2) production by polymorphonuclear leukocytes (PMNs) in the whole blood and the effects of plasma on these functions were investigated on 44 healthy mature neonates (term 37 to 41 weeks) and 15 premature neonates (term 30 to 36 weeks) using two color flow cytometric analysis. The results were compared to those of a healthy adult control group (n = 10). PMN phagocytic activity was low in both mature and premature neonates. H2O2 production of PMN with phorbol myristate acetate (PMA) stimulation and following phagocytosis was augmented in both mature and premature neonates. When plasma and PMNs of adults and neonates were separated and combined differently, phagocytic activity and H2O2 production of PMNs appeared to be principally regulated by the plasma employed. This finding indicates that plasma has major effects on both phagocytosis and H2O2 production by PMNs of newborn neonates.

A pilot study of continuous infusion Ara-C in combination with rhG-CSF in relapsed childhood acute myeloid leukemia

Relapse in acute myeloid leukemia (AML) following intensive chemotherapy bears a bad prognosis. We treated 18 children with relapsed AML on two separate protocols that included continuous infusion (CI) of cytosine arabinoside (ara-C) (total dose 4gr-6gr/m2) over 96-120 hours. In an attempt to increase the fraction of blasts in S-phase and render them more sensitive to cell-cycle specific agents such as ara-C, 10 patients received 5mcg/kg rhG-CSF twice daily beginning 48 hours before and continuing through the duration of the CI ara-C (POG #9192 study). The percentage of cells is S phase before and after G-CSF administration was determined. In a second group of patients (n = 8) who received ara-C alone, endogenous concentrations of G-CSF and serial blood counts were measured (St Jude's R4 study). The rationale of the St Jude's R4 was to optimize the schedule of the second course of ara-C at a time when the patient's endogenous G-CSF concentration was increased and thus maximize the percent of cells captured in S phase. Four out of 8 patients receiving CI ara-C alone and 4 out of 10 patients receiving CI ara-C with rhG-CSF achieved a complete remission (CR) after 1 cycle of therapy. Four patients in CR underwent marrow transplantation (2 allogeneic and 2 autologous). Cell cycle analysis of blast cells cultured in vitro with or without G-CSF showed a two fold increase in the percentage of cells in S phase (P = 0.03) whereas cells obtained from patients before and after G-CSF administration showed no difference in cell cycling. Correlation between G-CSF concentrations and ANC showed a negative association indicating that the regulatory mechanisms for G-CSF production remained intact. In our relatively small series, CI ara-C achieved a CR rate of 44% with rhG-CSF having no effect on the remission rate. Although in vitro rhG-CSF increased the percentage of blasts in S phase significantly, in vivo effects were not observed. Larger studies with combinations of different hematopoietic growth factors and cell-cycle active drugs are needed to evaluate the role of these cytokines in the therapy of recurrent AML.

Use of Hematopoietic Growth Factors in the Neonatal Intensive Care Unit

Recombinant hematopoietic growth factors have emerged as valuable treatments for a variety of medical conditions. Recently, their applications have reached the neonatal intensive care unit, where they offer new therapeutic options for problems as common as anemia of prematurity, or as catastrophic as neonatal sepsis. When facing bacterial infection, it is known that newborn infants are capable of increasing their serum G-CSF concentrations. However, their response does not reach the concentrations that adults are able to achieve, and frequently neutropenia complicates the picture of neonatal sepsis. Although Phase III clinical trials are still in progress, published animal studies, case reports, and Phase I trials suggest that neonates with a variety of neutropenias experience a rapid elevation in their blood neutrophil concentration following administration of rG-CSF, without significant adverse effects. Although many factors contribute to the development of the “anemia of prematurity,” one of the major factors is the inability of preterm infants to generate an erythropoietin (Epo) response appropriate to their degree of anemia. On the basis of this fact, administration of rEpo to preterm neonates to treat or to prevent the anemia of prematurity has been the subject of multiple clinical studies, and it is now clear that rEpo administration to this population can indeed result in lower transfusion requirements, with only occasional and mild adverse effects. Neonatal thrombocytopenia is also a frequent clinical problem, which in most patients develops without a clear underlying cause. Recent studies, quantifying circulating megakaryocyte progenitors in the peripheral blood of thrombocytopenic neonates, suggest that impaired megakaryocytopoiesis may be the main underlying mechanism of many cases of thrombocytopenia. On the basis of this finding, it is tempting to speculate that recombinant thrombopoietin, the newly discovered physiological stimulator of platelet production, will be of clinical relevance in the treatment of thrombocytopenic neonates.

Comparative effects of lipopolysaccharide on newborn versus adult rat hepatocyte and nonparenchymal cell cocultures

OBJECTIVE

To examine the effects of development on the response of hepatocytes and nonparenchymal cells to an endotoxin challenge as an in vitro model of organ system dysfunction at differing developmental ages.

DESIGN

In vitro animal cell culture model.

SETTING

University teaching hospital research laboratory.

SUBJECTS

Adult and newborn Sprague-Dawley rats.

INTERVENTIONS

The method of hepatocyte and nonparenchymal cell coculture was utilized and modified to allow evaluation of cells derived from newborns. Cells were isolated from adult rats by standard perfusion technique. Hepatocytes and nonparenchymal cells were isolated from newborn rats by use of identical enzymatic degradation after fine mincing of the organ. Isolated cells were purified by density gradient. The hepatocytes were incubated in standard cell culture plates for 24 hrs before the addition of nonparenchymal cells. Hepatocytes were incubated with similar-age nonparenchymal cells. After an additional 24 hrs, serial log dilutions of lipopolysaccharide were added as a stimulus and the system was cultured an additional 24 hrs. The response of the hepatocytes was assessed by determination of 3H-leucine incorporation in acid-precipitated protein. In addition, the production of tumor necrosis factor, interleukin (IL)-1, and IL-6 by isolated nonparenchymal cells from adult and newborn rats was determined after stimulation with serial log dilutions of lipopolysaccharide by bioassay.

MEASUREMENTS AND MAIN RESULTS

Both adult and newborn hepatocytes cocultivated with nonparenchymal cells demonstrated a comparable and statistically significant dose response to lipopolysaccharide (p < .01). The newborn hepatocytes demonstrated a greater rate of protein synthesis than the adult hepatocytes at all concentrations of lipopolysaccharide. Tumor necrosis factor production by newborn and adult nonparenchymal cells was similar at all lipopolysaccharide doses. IL-1 production demonstrated a positive dose response to lipopolysaccharide in the adult and newborn nonparenchymal cells, with a trend (p = .17) toward greater IL-1 secretion by the adult cells. There were significant differences in IL-6 production by isolated nonparenchymal cells at lipopolysaccharide doses of 0.01, 0.1, and 10 micrograms/mL. While a similar trend was apparent in the cocultured cells, the significance was not apparent, except at the highest lipopolysaccharide dose.

CONCLUSIONS

The dose responses of newborn and adult hepatocytes to nonparenchymal cells stimulated with lipopolysaccharide were similar, although newborn hepatocytes appeared to have an inherently higher rate of protein synthesis compared with adult hepatocytes. Cytokine production was similar in nonparenchymal cells of both ages, although IL-1 production by stimulated newborn nonparenchymal cells appeared to be less than IL-1 production by adult nonparenchymal cells.

Potential effectiveness of stored cord blood (non-frozen) for emergency use

Bone marrow has been used for a number of years to assist patients who have accidentally received potentially lethal levels of irradiation. The intent of the transplant is to replace the victim's own bone marrow that has been injured from the irradiation or to act as temporary support to allow the patient's own marrow to recover. Following the Chernobyl disaster, some victims received bone marrow that was HLA matched or partially matched. However, donor marrows were difficult to obtain in adequate numbers; as a substitute for bone marrow, frozen fetal liver cells were used as a source of hematopoietic stem cells. The use of fetal livers, however, was unsuccessful. Human umbilical cord blood, currently considered an excellent source of hematopoietic stem cells, was not used at Chernobyl. For several years, we have been able experimentally to keep SJL/J mice alive with the use of human umbilical cord blood after the animals received lethal levels of irradiation. This finding suggests that under certain conditions human cord blood does not have to be HLA matched to facilitate rescue from irradiation. In addition, there are reports of unmatched HLA cord blood being used successfully for marrow transplantation. If human cord blood does not have to be matched for HLA, there may be emergency cataclysmic circumstances where the availability of umbilical cord blood may be of considerable value. To simulate a clinical situation such as a nuclear accident, in which human cord blood might serve as a source of stem cells for marrow transplantation, we attempted to rescue immunocompetent mice after 900 cGY of irradiation with the use of (nonfrozen) human cord blood stored in a blood bank. The blood was stored under routine conditions (3-6 degrees C) for 5 and 7 days in special bags that allow transmission of oxygen. Following lethal levels of irradiation, the cord blood was administered to the animals and a significant survival rate was obtained.

Neutrophil respiratory burst in term and preterm neonates without signs of infection and in those with increased levels of C-reactive protein

Developmental immaturities in neonatal host defense predispose the neonates to an increased mortality rate during bacterial infections. Early diagnosis is of great clinical importance, but, especially in neonates, is sometimes very difficult. The ability to generate reactive oxygen species, the so-called respiratory burst, is essential for neutrophils to kill infectious microorganisms. Therefore, changes of respiratory burst may reflect increased susceptibility of neonates to infections and may be useful for the early detection of infections. Superoxide anion production was determined by a flow cytometric method using dihydrorhodamine 123 (DHR) as an oxidative probe after priming of neutrophils with PBS buffer (spontaneous burst), with N-formyl-methionyl-leucyl-phenylalanine (fMLP), or with Escherichia coli. During the study period, the spontaneous percentage of activated cells in whole blood as well as the percentage of activated cells in stimulation with fMLP was lower in adults (n = 100; PBS, 1.0 +/- 0.1%; fMLP, 8.3 +/- 0.9%) compared with neonates without signs of infection (n = 143). Among the latter, the percentage of activated cells (PBS and fMLP assay) varied with respect to gestational age and hours of life: lowest values were measured in preterm newborns with gestational age less than 32 wk and between 25 and 120 h of life. The same correlation to gestational age was true for total neutrophil cell counts. In neonates with increased levels of C-reactive protein during the first 5 d of life (n = 43), the percentages of activated cells after PBS and fMLP incubation were higher than those of neonates without signs of infection. The relationship of neutrophil respiratory burst and neutrophil cell counts to gestational age might reflect at least in part a reason for the increased susceptibility of neonates to infections. Furthermore, determination of respiratory burst may prove to be a new laboratory parameter of neonatal infection.

Diminished soluble and total cellular L-selectin in cord blood is associated with its impaired shedding from activated neutrophils

We have previously shown that surface levels of the adhesive glycoprotein, L-selectin, are diminished on cord blood neutrophils (polymorphonuclear leukocytes, PMN) and associated with impaired adherence to endothelium under flow conditions. To test the hypothesis that diminished surface levels reflect a total cellular deficiency, we measured L-selectin in PMN lysates and plasma from cord and adult blood. L-selectin content was decreased in cord blood PMN lysates compared with those of adults by both Western blot analyses and ELISA (cord blood, 1195 +/- 160 pg/mL; adult, 1870 +/- 260 pg/mL; X +/- SEM; p < 0.05). Soluble L-selectin levels were also decreased in cord blood plasma (324 +/- 24 ng/mL versus 537 +/- 28 ng/mLiter in adult plasma, p < 0.01). To evaluate L-selectin function, we next compared the dose dependent effect of several chemoattractants on shedding of L-selectin from cord blood and adult PMN. Adult PMN showed greater overall shedding of L-selectin as compared with cord blood PMN after stimulation with fMet-Leu-Phe (p < 0.03) and granulocyte-macrophage colony-stimulating factor (p < 0.02). In contrast, shedding of L-selectin was similar between groups after IL-8 tested stimulation. We conclude that cord blood PMN have a decreased cellular content of L-selectin in addition to an impaired ability to shed surface L-selectin in response to specific inflammatory mediators.

Plasma concentration of granulocyte-colony-stimulating factor in neonates

We determined the plasma concentration of granulocyte-colony-stimulating factor (GCSF) and the neutrophil count in 108 infants (gestational age 23-41 weeks; birthweight 478-4935g). The GCSF levels in the very low birthweight infants without infection were comparable to those in the full-term infants. Infants as premature as 23 weeks of gestation showed similar GCSF levels to mature neonates. GCSF levels decreased significantly by day 7 after birth. The levels were not significantly correlated with the neutrophil count. The mean plasma level of GCSF increased significantly when infection developed and was significantly higher in the infants with sepsis than in those with non-septic infections (p < 0.01). The results suggest that GCSF may be the major determinant of neutrophil kinetics both during fetal life and after birth.

Autologous umbilical cord blood transfusion

The purpose of this study was to examine some aspects of umbilical cord blood collection for autologous transfusion in premature infants. All 120 microbacterial cultures (aerobic and anaerobic) of cord blood samples as well as 30 cultures of mycoplasma were treated. Cord prothrombin fragment (F 1 + 2) concentrations were quantified at one and 10 minutes after clamping of the cord. F 1 + 2 concentrations assessed on 25 newborn infants were similar and no linear association with time of clamping could be drawn. This means that cord blood thrombosis is not activated for at least 10 minutes following clamping of the cord. As far as is known, the first newborn infant to benefit from this method of transfusion is reported here. The premature infant received two portions of autologous blood (on days 5 and 7). No untoward effects were noted. Blood, collected from the umbilical cord, is a safe source for autotransfusion, provided that bacteriological testing has been carried out.

Granulocyte-colony stimulating factor levels in cord blood and neonatal peripheral blood

We measured the granulocyte-colony stimulating factor (G-CSF) levels in cord blood and peripheral blood obtained from full-term or pre-term infants during the first 3 days of birth. The mean G-CSF level among cord blood (17.2 pg/mL) was similar to that of peripheral blood on day 0 (18.3 pg/mL) and day 1 (13.6 pg/mL), while that of peripheral blood on day 0 was significantly higher than on day 2 (10.9 pg/mL) and day 3 (8.8 pg/mL; both P < 0.05). There was no correlation between neutrophil counts and G-CSF levels. No difference was found in neutrophil counts or G-CSF levels between infants who weighed more or less than 2500 g at birth. These results suggest that the neonatal neutrophil count depends on regulatory factors other than G-CSF.

Increased granulocyte-colony stimulating factor (G-CSF) levels in neonates with perinatal complications

We have investigated cord blood granulocyte-colony stimulating factor (G-CSF) levels in neonates with or without neonatal complications to examine some changes in the G-CSF levels in the neonatal period. The G-CSF levels were measured in 613 neonates by enzyme immunoassay. The results showed that G-CSF levels were distributed in a broad range from the level under the cutting point (31 pg/mL) to over the measurable range (2000 pg/mL). Normal neonates without perinatal complications were 322. In normal neonates, the G-CSF level correlated with the gestational age (r = 0.255, P < 0.01) and cord blood leukocyte count (r = 0.210, P < 0.01). The G-CSF values were under 100 pg/mL in 95% of normal neonates with a median of 35.0 pg/mL. We divided the neonates into two groups: a lower (< 100 pg/mL) and a higher (> or = 100 pg/mL), based on the G-CSF level. The percentage of neonates with higher G-CSF levels (> or = 100 pg/mL) was greater in neonates with perinatal complications than in normal neonates (< 100 pg/mL; P < 0.01). Compared with normal neonates, the percentages of the higher group were greater in neonates with infections (P < 0.01), fetal distress (P < 0.01), premature rupture of membranes (P < 0.05), neonatal asphyxia (P < 0.01) and meconium staining of amniotic fluid (P < 0.01). Neonates with higher G-CSF levels had larger numbers of peripheral leukocytes (P < 0.05) than did those with the lower G-CSF levels. Counts of leukocytes were parallel with those of neutrophils.(ABSTRACT TRUNCATED AT 250 WORDS)

The expression of IgG Fc receptors on circulating leucocytes in the fetus and new-born

The expression of Fc-gamma-R (FcR) classes on circulating leucocyte lineages (lymphocytes, monocytes, granulocytes) was determined by flow cytometry in 46 fetuses at 18-35 weeks of gestation and in 11 full-term neonates, and compared to that in 20 adults. Classes of FcR present on adult leucocytes could be detected on the corresponding fetal cells as early as 18 weeks of pregnancy. Generally, in the fetus, FcR expression was lower than in the adult while in the neonate it approached values found later in life. However, percentages of Fc-gamma-RIII-positive fetal/new-born monocytes, and those of FcR-positive new-born granulocytes were considerably raised above adult levels. The modified pattern of FcR expression on fetal/new-born leucocytes is likely to influence their IgG-mediated effector activities towards targets such as red cells and platelets.

Plasma granulocyte-colony stimulating factor concentrations ([G-CSF]) in the early neonatal period

We studied G-CSF concentrations ([G-CSF]) at birth and their relationship with neutrophil count, incidence of infection, gestational age, labour, and the presence of maternal pregnancy-induced hypertension. Plasma [G-CSF] were significantly elevated in babies with suspected infection and in those of hypertensive mothers, compared to healthy babies delivered by elective caesarian section (median [range] = 3101 [75- > 5000] pg/ml and 153 [45-857] pg/ml versus 32 [11-266] pg/ml; P < 0.0001); and were unrelated to neutrophil count and gestational age. Initial high concentrations (> 100 pg/ml) declined by 7 d (P < 0.0001).

Human cord blood cells as targets for gene transfer: potential use in genetic therapies of severe combined immunodeficiency disease

Human cord blood (CB) contains large numbers of both committed and primitive hematopoietic progenitor cells and has been shown to have the capacity to reconstitute the lympho-hematopoietic system in transplant protocols. To investigate the potential usefulness of CB stem and progenitor cell populations to deliver new genetic material into the blood and immune systems, we have transduced these cells using retroviral technology and compared the efficiency of gene transfer into CB cells with normal adult human bone marrow cells using a variety of infection protocols. Using two retroviral vectors which differ significantly in both recombinant viral titers and vector design, low density CB or adult bone marrow (ABM) cells were infected, and committed progenitor and more primitive hematopoietic cells were analyzed for gene expression by G418 drug resistance (G418r) of neophosphotransferase and protein analysis for murine adenosine deaminase (mADA). Standard methylcellulose progenitor assays were used to quantitate transduction efficiency of committed progenitor cells, and the long term culture-initiating cell (LTC-IC) assay was used to quantitate transduction efficiency of more primitive cells. Our results indicate that CB cells were more efficiently transduced via retroviral-mediated gene transfer as compared with ABM-derived cells. In addition, stable expression of the introduced gene sequences, including the ADA cDNA, was demonstrated in the progeny of infected LTC-ICs after 5 wk in long-term marrow cultures. Expression of the introduced ADA cDNA was higher than the endogenous human ADA gene in the LTC-IC-derived colonies examined. These studies demonstrate that CB progenitor and stem cells can be efficiently infected using retroviral vectors and suggest that CB cells may provide a suitable target population in gene transfer protocols for some genetic diseases.

Interleukin-3, interleukin-6, granulocyte-macrophage colony-stimulating factor and erythropoietin cord blood levels of preterm and term neonates

The cascade of known haematopoietic growth factors controlling granulomonopoiesis and erythropoiesis includes interleukin-3 (IL-3), interleukin-6 (IL-6), granulocyte-macrophage colony-stimulating factor (GM-CSF), and erythropoietin (EPO). Elevated endogenous IL-3 and IL-6 cord blood levels in infection-free premature and mature neonates may reflect their possible role for expansion of haematopoietic progenitor cells, granulocytes and monocytes. Within the erythroid lineage a synergistic action of IL-3, IL-6 and EPO can be assumed. To identify the regulatory role in fetal haematopoietic expansion cord blood plasma levels of these haematopoietic growth factors were assessed in 19 premature and 20 mature infants using commercial enzyme-linked immunosorbent assay and enzyme-amplified sensitivity immuno assay test kits. Peripheral blood IL-3, GM-CSF and EPO were studied in 5 and 10 premature infants respectively. Compared with cord blood levels we found a decline in EPO levels but no decrease of IL-3 and GM-CSF during the 1st month of life. We conclude that postnatal decrease in plasma burst-promoting activity levels in preterm infants is mainly explained by low postnatal EPO levels.

A case of congenital leukemia with monosomy 7

A case of congenital leukemia with monosomy 7 is reported. Immunological study of the blast cells using monoclonal antibodies was suggestive of both myelomegakaryocytic and T-lymphoblastic leukemia. Chromosomal analysis of the bone marrow cells showed monosomy 7. Chemotherapy was initiated with a combination of adriamycin, cytosine arabinoside, 6-mercaptopurine, and prednisolone. The patient obtained complete remission, which has been maintained for 4 years and 1 month. He receives no chemotherapy now. Our case shows that monosomy 7 in congenital leukemia is rare, but the presence of monosomy 7 in congenital leukemia does not necessarily indicate a poor prognosis.

Serum granulocyte colony-stimulating factor levels in umbilical cord blood of normal full-term neonates

We measured granulocyte colony-stimulating factor (G-CSF) levels in cord blood of 59 normal full-term neonates immediately after birth and the subsequent changes in G-CSF levels of 16 cases by our modified enzyme-linked immunosorbent assay (ELISA) for G-CSF. Ten out of 59 cases examined (17%) showed G-CSF levels in cord blood after delivery between 20 and 57 pg/ml, although in the remaining cases, the G-CSF levels were below 20 pg/ml, which was our minimal detection level. A direct relationship between G-CSF levels and white blood cell count, absolute granulocyte numbers in cord blood, gestation age or weight was not observed. Although G-CSF levels in cord blood after delivery remained below 20 pg/ml in 5 cases out of 16 tested, those in the remaining 11 cases (69%) subsequently became elevated after delivery. The peak G-CSF level in cord blood after delivery ranged from 26-364 pg/ml, and the time of it was between 4.5 and 18 h. As G-CSF level per wet weight of placenta was high (124 x 29 pg/ml), these subsequent elevations of G-CSF in cord blood after delivery may result from a gradual influx from the placenta.

PMN adhesion and extravasation as a paradigm for tumor cell dissemination

Current evidence indicates that the localization and extravasation of neutrophils is a complex process involving several adhesion molecules with apparently distinct functions, and a highly coordinated and dynamic interplay between the neutrophil and the endothelial cell that is influenced by the shear forces present at the interface between these two cell types. Chemotactic stimulation of the neutrophil not only induces directed locomotion but markedly alters the surface expression and functions of the neutrophil adhesion molecules, having both an upregulating and downregulating influence. Cytokines such as interleukin 1 induce the synthesis and surface expression of endothelial adhesion molecules such as ICAM-1 and ELAM-1, and stimuli such as thrombin and histamine induce the rapid mobilization to the endothelial surface of another adhesion molecule, GMP-140. Transendothelial migration of neutrophils in most settings both in vitro and in vivo appears to require CD18 integrins on the neutrophil and ICAM-1 on the endothelial cells. This is most clearly demonstrated by the genetic deficiency of CD18 in humans, dogs and cattle, where neutrophil extravasation at most inflammatory sites is almost completely absent. Though the coordinated functions of the various neutrophil and endothelial adhesion molecules are highly efficient in promoting neutrophil extravasation, there has been relatively little investigation of their utilization in tumor cell dissemination. Recent results indicate that such studies may prove fruitful. For example, some adenocarcinoma cell lines express the complex carbohydrate (sialyl Lewis x) recently shown to be a ligand for ELAM-1.

Neonatal interleukin-1 beta, interleukin-6, and tumor necrosis factor: cord blood levels and cellular production

In a prospective study, levels of interleukin-1 beta (IL-1 beta), interleukin-6) (IL-6), and tumor necrosis factor (TNF) were measured in a blind fashion in cord blood plasma from 92 neonates by specific immunoassays, and were correlated with the clinical courses of the infants, including type of delivery and perinatal complications. Plasma IL-1 beta concentration was undetectable in infants born by normal vaginal delivery or elective cesarean section but was significantly increased in infants born after induced vaginal deliveries (142 +/- 68 pg/ml) or urgent cesarean section (290 +/- 21 pg/ml; both p less than 0.05 compared with normal deliveries). The IL-1 beta levels were elevated in infants with severe perinatal complications (282 +/- 116 pg/ml; p less than 0.001), whereas TNF and IL-6 levels were not related to these complications. Infants with isolated perinatal infectious complications had elevated levels of plasma IL-6 compared with those of sick neonates without infection (p less than 0.001). In contrast, TNF plasma levels and IL-1 beta production by cord blood leukocytes were decreased in infants with infectious complications alone (both p less than 0.05). These studies suggest that the levels of IL-1 beta, IL-6, and TNF in the cord plasma relate differentially to clinical complications in the perinatal period.