Preliminary report: rhG-CSF may reduce the incidence of neonatal sepsis in prolonged preeclampsia-associated neutropenia

Consequences of early-onset preeclampsia on neonatal morbidity and mortality

Preterm birth is the leading cause of perinatal morbidity and mortality in developed countries. Common reasons for indicated preterm births include pre-eclampsia. The increase in incidences of morbidity and mortality observed in neonates resulting from pregnancies complicated by preeclampsia is also due to alterations in angiogenic and pro-inflammatory factors that directly affect the neonatal health. This review was prepared with the aim of gathering the information available at PubMed/MEDLINE, in the years from 2011 to 2021, on the consequences of neonatal morbidity and mortality of early-onset preeclampsia. There is great controversy in the literature and paucity of studies. Early onset pre-eclampsia has been linked to fetal growth restriction (FGR). Most studies support its association with respiratory distress syndrome (RDS). Most studies point to an association between preeclampsia and bronchopulmonary dysplasia (BPD), with the highest risk in FGR. The association between preeclampsia, patent ductus arteriosus (PDA) and sepsis is not supported by the literature. The association to necrotizing enterocolitis (NEC) is controversial. The risk of spontaneous intestinal perforation (SIP) seems to be increased with preeclampsia. The association between intraventricular hemorrhage (IVH) and preeclampsia is controversial, however, preeclampsia seems to have a protective effect on periventricular leukomalacia (PVL). Most of the evidence points to the non-association between preeclampsia and retinopathy of prematurity (ROP). Hematological changes such as neutropenia, thrombocytopenia and increased nucleated red blood cell counts have been shown to be associated with preeclampsia. The evidence is still quite controversial regarding mortality. The early installation of preeclampsia will have direct consequences on neonatal morbidity. Gestational age at preterm birth is the main risk factor on neonatal morbidity. Obstetricians should aim to prolong the pregnancies complicated by early-onset severe preeclampsia as far as maternal conditions allow. This policy may contribute to improve the neonatal outcomes.

Modulation of preeclampsia by the cholinergic anti-inflammatory pathway: Therapeutic perspectives

The cholinergic anti-inflammatory pathway (CAP) is vital for the orchestration of the immune and inflammatory responses under normal and challenged conditions. Over the past two decades, peripheral and central circuits of CAP have been shown to be critically involved in dampening the inflammatory reaction in a wide array of inflammatory disorders. Additionally, emerging evidence supports a key role for CAP in the regulation of the female reproductive system during gestation as well as in the advent of serious pregnancy-related inflammatory insults such as preeclampsia (PE). Within this framework, the modulatory action of CAP encompasses the perinatal maternal and fetal adverse consequences that surface due to antenatal PE programming. Albeit, a considerable gap still exists in our knowledge of the precise cellular and molecular underpinnings of PE/CAP interaction, which hampered global efforts in safeguarding effective preventive or therapeutic measures against PE complications. Here, we summarize reports in the literature regarding the roles of peripheral and reflex cholinergic neuroinflammatory pathways of nicotinic acetylcholine receptors (nAChRs) in reprogramming PE complications in mothers and their progenies. The possible contributions of α7-nAChRs, cholinesterases, immune cells, adhesion molecules, angiogenesis, and endothelial dysfunction to the interaction have also been reviewed.

Medicinal Uses of Hematopoietic Growth Factors in Neonatal Medicine

This review focuses on certain hematopoietic growth factors that are used as medications in clinical neonatology. It is important to note at the chapter onset that although all of the pharmacological agents mentioned in this review have been approved by the US Food and Drug administration for use in humans, none have been granted a specific FDA indication for neonates. Thus, in a sense, all of the agents mentioned in this chapter could be considered experimental, when used in neonates. However, a great many of the pharmacological agents utilized routinely in neonatology practice do not have a specific FDA indication for this population of patients. Consequently, many of the agents reviewed in this chapter are considered by some practitioners to be nonexperimental and are used when they judge such use to be "best practice" for the disorders under treatment.The medicinal uses of the agents in this chapter vary considerably, between geographic locations, and sometimes even within an institutions. "Consistent approaches" aimed at using these agents in uniform ways in the practice of neonatology are encouraged. Indeed some healthcare systems, and some individual NICUs, have developed written guidelines for using these agents within the practice group. Some such guidelines are provided in this review. It should be noted that these guidelines, or "consistent approaches," must be viewed as dynamic and changing, requiring adjustment and refinement as additional evidence accrues.

Effectiveness of Granulocyte Colony-Stimulating Factor in Hospitalized Infants with Neutropenia

Objective The objective of this study was to determine the time to hematologic recovery and the incidence of secondary sepsis and mortality among neutropenic infants treated or not treated with granulocyte colony-stimulating factor (G-CSF). Study Design We identified all neutropenic infants discharged from 348 neonatal intensive care units from 1997 to 2012. Neutropenia was defined as an absolute neutrophil count ≤ 1,500/µL for ≥ 1 day during the first 120 days of life. Incidence of secondary sepsis and mortality and number of days required to reach an absolute neutrophil count > 1,500/µL for infants exposed to G-CSF were compared with those of unexposed infants. Results We identified 30,705 neutropenic infants, including 2,142 infants (7%) treated with G-CSF. Treated infants had a shorter adjusted time to hematologic recovery (hazard ratio: 1.36, 95% confidence interval [CI]: 1.30-1.44) and higher adjusted odds of secondary sepsis (odds ratio [OR]: 1.50, 95% CI: 1.20-1.87), death (OR: 1.33, 95% CI: 1.05-1.68), and the combined outcome of sepsis or death (OR: 1.41, 95% CI: 1.19-1.67) at day 14 compared with untreated infants. These differences persisted at day 28. Conclusion G-CSF treatment decreased the time to hematologic recovery but was associated with increased odds of secondary sepsis and mortality in neutropenic infants. G-CSF should not routinely be used for infants with neutropenia.

Characterization of recombinant human granulocyte colony-stimulating factor expression by FT-IR spectroscopy: Studies on thermal induction and media formulation on the stability of the protein secondary structure

The Fourier-transform infrared (FT-IR) spectroscopic approach has been employed to understand the recombinant human G-CSF (rhG-CSF) protein accumulation, secondary structure, and thermal stability in Escherichia coli grown under a temperature shift strategy (37 and 28°C) in various media formulations. The choline + sodium pyruvate (37°C) and sodium pyruvate (28°C) formulations have shown the highest inclusion body (IB) accumulation of 0.41 and 0.46 mg/mL, respectively. Furthermore, insights on the structure of the rhG-CSF within IBs and intact cells have been investigated through secondary structure analysis. Thermal stability experiments were also carried out to explain the pattern of the second derivative structure of rhG-CSF. The studies showed that choline + sodium pyruvate formulation has preserved the protein secondary structure even at 82°C. Overall, the FT-IR spectroscopic technique can also be adopted to accelerate the characterization of other recombinant therapeutic proteins of E. coli origin.

A Dormant Microbial Component in the Development of Preeclampsia

Preeclampsia (PE) is a complex, multisystem disorder that remains a leading cause of morbidity and mortality in pregnancy. Four main classes of dysregulation accompany PE and are widely considered to contribute to its severity. These are abnormal trophoblast invasion of the placenta, anti-angiogenic responses, oxidative stress, and inflammation. What is lacking, however, is an explanation of how these themselves are caused. We here develop the unifying idea, and the considerable evidence for it, that the originating cause of PE (and of the four classes of dysregulation) is, in fact, microbial infection, that most such microbes are dormant and hence resist detection by conventional (replication-dependent) microbiology, and that by occasional resuscitation and growth it is they that are responsible for all the observable sequelae, including the continuing, chronic inflammation. In particular, bacterial products such as lipopolysaccharide (LPS), also known as endotoxin, are well known as highly inflammagenic and stimulate an innate (and possibly trained) immune response that exacerbates the inflammation further. The known need of microbes for free iron can explain the iron dysregulation that accompanies PE. We describe the main routes of infection (gut, oral, and urinary tract infection) and the regularly observed presence of microbes in placental and other tissues in PE. Every known proteomic biomarker of "preeclampsia" that we assessed has, in fact, also been shown to be raised in response to infection. An infectious component to PE fulfills the Bradford Hill criteria for ascribing a disease to an environmental cause and suggests a number of treatments, some of which have, in fact, been shown to be successful. PE was classically referred to as endotoxemia or toxemia of pregnancy, and it is ironic that it seems that LPS and other microbial endotoxins really are involved. Overall, the recognition of an infectious component in the etiology of PE mirrors that for ulcers and other diseases that were previously considered to lack one.

Early-Onset Neutropenia in Small-for-Gestational-Age Infants

BACKGROUND

Early neutropenia is more common in small for gestational age (SGA) neonates (birth weight <10th percentile) than in appropriately grown neonates. However, several aspects of this variety of neutropenia are unknown, including the duration, kinetic mechanism, and outcomes.

METHODS

Using 10 years of multihospital records, we studied SGA neonates who, during the first week after birth, had neutrophil counts <1000/μL.

RESULTS

This degree of neutropenia was more common in SGA neonates (6%, 207/3650) than in non-SGA matched controls (1%, 46/3650; P < .001). Neutrophil counts stayed below the lower reference interval for 7 days. Ratios of immature to total neutrophils were within the reference interval, suggesting reduced neutrophil production, not accelerated neutrophil use or destruction. Increased nucleated red cells at birth correlated with decreased neutrophils (P < .001). Neutropenia was not independently associated with maternal hypertensive disorders, over and above the effect of SGA. Of 201 neutropenic SGA neonates, 129 (64%) also had thrombocytopenia. Sixteen percent of neutropenic neonates were treated with recombinant granulocyte colony-stimulating factor (rG-CSF) or intravenous immunoglobulin (IVIG), with no reduction in late-onset sepsis or necrotizing enterocolitis (NEC). Regression analysis showed that neutropenia (but not thrombocytopenia in the absence of neutropenia) was independently associated with increased odds of developing necrotizing enterocolitis (odds ratio 4.01, 90% confidence interval 2.08 to 7.35, P < .001).

CONCLUSIONS

Neutropenia of SGA is a condition of 1-week duration. It is more closely associated with SGA than maternal hypertension (likely owing to neutrophil hypoproduction associated with intrauterine hypoxia), often accompanied by thrombocytopenia, not obviously improved by rG-CSF or IVIG, and associated with an increased risk for NEC.

Efficacy of recombinant human granulocyte colony stimulating factor in very-low-birth-weight infants with early neutropenia

BACKGROUND/PURPOSE

Neutropenia is a risk factor for nosocomial infections (NI) in very-low-birth-weight (VLBW) infants. Although recombinant human granulocyte colony stimulating factor (rhG-CSF) increases the neutrophil counts in neutropenic VLBW infants, its long-term efficacy for early neutropenia (EN) remains unknown.

METHODS

In this case-controlled study, charts of VLBW recipients of rhG-CSF for EN (total neutrophil count <1.5 × 10(9)/L during first 7 days) were reviewed and compared to gestational age, total neutrophil count, and birth weight matched infants unexposed to rhG-CSF.

RESULTS

Twenty-seven infants were identified in each group. Mortality and morbidity did not differ between the two groups. Rate of NI (16/27 vs. 4/27, p = 0.002, odds ratio = 8.36) as well as the total number of episodes of NI (22 vs. 4, p = 0.007) were higher in rhG-CSF (+) group than in the rhG-CSF (-) group.

CONCLUSION

Our experience does not show benefit in empirical use of rhG-CSF in preventing NI in VLBW infants with EN.

Neutropenia in the newborn

PURPOSE OF REVIEW

The aim is to review normal blood neutrophil concentrations and the clinical approach to neutropenia in the neonatal period. A literature search on neonatal neutropenia was performed using the databases PubMed, EMBASE, and Scopus, and the electronic archive of abstracts presented at the annual meetings of the Pediatric Academic Societies.

RECENT FINDINGS

The review summarizes current knowledge on the causes of neutropenia in premature and critically ill neonates, focusing on common causes such as maternal hypertension, neonatal sepsis, twin-twin transfusion, alloimmunization, and hemolytic disease. The article provides a rational approach to diagnosis and treatment of neonatal neutropenia, including current evidence on the role of recombinant hematopoietic growth factors.

SUMMARY

Neutrophil counts should be carefully evaluated in premature and critically ill neonates. Although neutropenia is usually benign and runs a self-limited course in most neonates, it can be prolonged, and it constitutes a serious deficiency in antimicrobial defense in some infants.

Granulocyte Colony-stimulating Factor for Preterms with Sepsis and Neutropenia: A Randomized Controlled Trial

Background:

Bacterial sepsis is one of the major causes of mortality in newborn infants. Mortality increases when sepsis is associated with neutropenia.

Materials and Methods:

We conducted a prospective, randomized, double-blind, placebo-controlled trial of recombinant human granulocyte colony-stimulating factor on preterm neonates (gestational age (GA) <34 weeks) with sepsis and absolute neutrophil count (ANC) of <1500 cells/mm³. Mortality, duration of Neonatal Intensive Care Unit (NICU) stay, hematological parameters (ANC, platelet count, and total leukocyte count) were compared between the two groups. The GCSF group (n=39) received GCSF intravenously in a single daily dose of 10 μg/kg/day in a 5% dextrose solution over 20-40 min for three consecutive days, while the control group (n=39) received placebo of an equivalent volume of 5% dextrose.

Results:

Baseline demographic profile among the two groups was comparable. Mortality rate in the GCSF group was significantly lower than in the control group (10% vs. 35%; P<0.05). By day 3 of treatment, ANC in the GCSF group was significantly higher (3521±327) compared to 2094±460 in the control group, with P value being <0.05. Duration of NICU stay also decreased significantly in the GCSF group.

Conclusion:

The administration of GCSF in preterms with septicemia and neutropenia resulted in lower mortality rates. Further studies are required to confirm our results and establish this adjunctive therapy in neonatal sepsis.

Recombinant human granulocyte colony-stimulating factor in preterm neonates with sepsis and relative neutropenia: a randomized, single-blind, non-placebo-controlled trial

We performed a prospective, randomized, single-blind, non-placebo-controlled trial on preterm (<37 weeks) neonates (birth weight <2000g) with sepsis and absolute neutrophil counts (ANC) <5000 cells mm(-3) to study the effect of recombinant human granulocyte colony-stimulating factor (rhG-CSF) on all-cause-neonatal mortality and hematological parameters (total leucocyte (TLC, ANC, absolute monocyte and absolute platelet counts). The rhG-CSF group (n = 20) received 10 µg/kg/day of intravenous infusion of rhG-CSF once daily for 5 days along with conventional therapy, and the control group (n = 20) received conventional therapy alone. Hematological parameters on Days 0, 1, 3, 5, 7 and 14 of study entry and all-cause mortality rates at discharge were recorded. Baseline characteristics between the rhG-CSF and control group including mean birth weight (1395 ± 289 vs. 1500 ± 231g), mean gestational age (31.5 ± 2.68 vs. 32.6 ± 2.23 weeks), initial neonatal complaints and maternal characteristics were comparable. Mortality rates were significantly less among the rhG-CSF group (3/20 (15%) vs. 7/20 (35%), p < 0.05). By Day 5 (for TLC) and Day 3 (for ANC) of start of the intervention, rhG-CSF group had significantly higher TLC (8189 ± 1570 vs. 6936 ± 1128 cells mm(-3), p < 0.05) and ANC (4756 ± 1089 vs. 4213 ± 354 cells mm(-3), p < 0.05) compared to controls. ANC levels recovered to levels >5000 cells mm(-3) faster in the rhG-CSF group, with 80% babies having ANC >5000 cells mm(-3) by Day 7 of study entry compared with 35% in the control group (p < 0.05). Preterm neonates with sepsis and neutropenia treated with rhG-CSF adjunctive therapy have decreased all-cause mortality at discharge and a quicker recovery of their total leucocyte and ANC.

The role of granulocyte colony-stimulating factor in the neutrophilia observed in the fetal inflammatory response syndrome

OBJECTIVES

Fetal neutrophilia is present in two-thirds of cases with the fetal inflammatory response syndrome (FIRS). The mechanisms responsible for this finding have not been elucidated. Granulocyte colony-stimulating factor (G-CSF) is the primary physiologic regulator of neutrophil production and plays a key role in the rapid generation and release of neutrophils in stressful conditions (i.e., infection). The objective of this study was to determine: 1) whether FIRS was associated with changes in fetal plasma G-CSF concentrations; and 2) if fetal plasma G-CSF concentrations correlated with fetal neutrophil counts, chorioamnionitis, neonatal morbidity/mortality and cordocentesis-to-delivery interval.

STUDY DESIGN

Percutaneous umbilical cord blood sampling was performed in a population of patients with preterm labor (n=107). A fetal plasma interleukin-6 (IL-6) concentration >11 pg/mL was used to define FIRS. Cord blood G-CSF was measured by a sensitive and specific immunoassay. An absolute neutrophil count was determined and corrected for gestational age. Receiver operating characteristic (ROC) curve, survival analysis and Cox proportional hazard model were employed.

RESULTS

1) G-CSF was detected in all fetal blood samples; 2) fetuses with FIRS had a higher median fetal plasma G-CSF concentration than those without FIRS (P<0.001); 3) a fetal plasma G-CSF concentration ≥134 pg/mL (derived from an ROC curve) was associated with a shorter cordocentesis-to-delivery interval, a higher frequency of chorioamnionitis (clinical and histological), intra-amniotic infection, and composite neonatal morbidity/mortality than a fetal plasma concentration below this cut-off; and 4) a fetal plasma G-CSF concentration ≥134 pg/mL was associated with a shorter cordocentesis-to-delivery interval (hazard ratio 3.2; 95% confidence interval 1.8-5.8) after adjusting for confounders.

CONCLUSIONS

1) G-CSF concentrations are higher in the peripheral blood of fetuses with FIRS than in fetuses without FIRS; and 2) a subset of fetuses with FIRS with elevated fetal plasma G-CSF concentrations are associated with neutrophilia, a shorter procedure-to-delivery interval, chorio-amnionitis and increased perinatal morbidity and mortality.

Maternal preeclampsia and neonatal outcomes

Preeclampsia is a multiorgan, heterogeneous disorder of pregnancy associated with significant maternal and neonatal morbidity and mortality. Optimal strategies in the care of the women with preeclampsia have not been fully elucidated, leaving physicians with incomplete data to guide their clinical decision making. Because preeclampsia is a progressive disorder, in some circumstances, delivery is needed to halt the progression to the benefit of the mother and fetus. However, the need for premature delivery has adverse effects on important neonatal outcomes not limited to the most premature infants. Late-preterm infants account for approximately two thirds of all preterm deliveries and are at significant risk for morbidity and mortality. Reviewed is the current literature in the diagnosis and obstetrical management of preeclampsia, the outcomes of late-preterm infants, and potential strategies to optimize fetal outcomes in pregnancies complicated by preeclampsia.

Neonatal sepsis and neutrophil insufficiencies

Sepsis has continuously been a leading cause of neonatal morbidity and mortality despite current advances in chemotherapy and patient intensive care facilities. Neonates are at high risk for developing bacterial infections due to quantitative and qualitative insufficiencies of innate immunity, particularly granulocyte lineage development and response to infection. Although antibiotics remain the mainstay of treatment, adjuvant therapies enhancing immune function have shown promise in treating sepsis in neonates. This article reviews current strategies for the clinical management of neonatal sepsis and analyzes mechanisms underlying insufficiencies of neutrophil defense in neonates with emphasis on new directions for adjuvant therapy development.

Sepsis and neutropenia in very low birth weight infants delivered of mothers with preeclampsia

OBJECTIVE

To study the association between maternal preeclampsia and neonatal sepsis in very low birth weight newborns.

STUDY DESIGN

We studied all infants with birth weights between 500 g and 1500 g who were admitted to 6 neonatal intensive care units of the Brazilian Network on Neonatal Research for 2 years. Exclusion criteria were major malformations, death in the delivery room, and maternal chronic hypertension. Absolute neutrophil count was performed in the first 72 hours of life.

RESULTS

A total of 911 very low birth weight infants (preeclampsia, 308; non-preeclampsia, 603) were included. The preeclampsia group had significantly higher gestational age, more cesarean deliveries, antenatal steroid, central catheters, total parenteral nutrition, and neutropenia, and less rupture of membranes>18 hours and mechanical ventilation. Both groups had similar incidences of early sepsis (4.6% and 4.2% in preeclampsia and non-preeclampsia groups, respectively) and late sepsis (24% and 22.1% in preeclampsia and non- preeclampsia groups, respectively). Vaginal delivery and neutropenia were associated with multiple logistic regressions with early sepsis, and mechanical ventilation, central catheter, and total parenteral nutrition were associated with late sepsis. Death was associated with neutropenia in very preterm infants.

CONCLUSIONS

Preeclampsia did not increase neonatal sepsis in very low birth weight infants, and death was associated with neutropenia in very preterm infants.

A multicenter, randomized, placebo-controlled trial of prophylactic recombinant granulocyte-colony stimulating factor in preterm neonates with neutropenia

OBJECTIVE

To test the hypothesis that prophylactic treatment of neutropenic premature neonates with recombinant granulocyte-colony stimulating factor (rG-CSF) would reduce the incidence of nosocomial infections (NIs).

STUDY DESIGN

A total of 25 neonatal intensive care units participated in this multicenter, randomized, double-blind, placebo-controlled trial. Premature infants of gestational age (GA) <or= 32 weeks were included if they had a peripheral blood count showing < 1500 neutrophils/mm(3) for at least 24 hours during the first 3 weeks of life. A total of 200 infants received either rG-CSF (10 microg/kg/day) or placebo for 3 days. Primary outcome was survival free of infection for 4 weeks after treatment, assessed in an intention-to-treat analysis.

RESULTS

A total of 102 infants received rG-CSF (mean GA, 29.2 weeks), and 98 received placebo (mean GA, 29.1 weeks). Survival free of confirmed infection for 4 weeks after treatment was 74/102 in the rG-CSF group and 66/98 in the placebo group (P = .42). However, during 2 weeks, there was a significant difference between groups (86/102 vs 70/98; P = .028).

CONCLUSIONS

In this population, prophylactic rG-CSF did not significantly increase survival free of infection at 4 weeks after treatment. The transient effect observed at 2 weeks in the most immature infants should be evaluated further.

Early neutropenia is not associated with an increased rate of nosocomial infection in very low-birth-weight infants

BACKGROUND

Evidence is contradictory whether very low-birth-weight (VLBW, birth weight <1500 g) infants with early neutropenia (NP), especially those born to mothers with preeclampsia experience a greater incidence of nosocomial infection (NI).

OBJECTIVE

To investigate whether NP within the first 7 days of life is a risk factor for NI in VLBW infants.

METHODS

Over a 42-month period, we identified all VLBW infants born at <or=34 weeks gestation who survived for more than 72 h. Infants who had no evidence of early infection, who had at least one complete blood count performed in the first week of life, and who were not given prophylactic recombinant human granulocyte colony-stimulating factor (rhG-CSF) were included in this retrospective study. Early NP was defined as an absolute neutrophil count less than 1500 per microl at any time during the first week of life. NI was defined as the culture of a bacterial or fungal pathogen from a sterile body fluid that was obtained after 72 h of life in an infant with one or more clinical signs of infection.

RESULTS

A total of 338 VLBW infants were reviewed. Of those, 51 infants were excluded because of death or onset of an infection before 72 h of age, lack of a complete blood count in the first week of life or treatment with rhG-CSF. Of the remaining 287 infants, NI occurred in 11 of 77 (14.3%) infants with early NP compared to 42 of 210 (20.0%) infants without early NP (P=0.31). Infants who developed NI were smaller and less mature, had lower Apgar scores, were more frequently instrumented with central lines and required a longer duration of parenteral nutrition compared to infants without NI. Infants with NI also had a higher mortality and a greater incidence of necrotizing enterocolitis, severe intraventricular hemorrhage and threshold retinopathy of prematurity. However, using stepwise multivariate logistic regression analysis, only the duration of parenteral nutrition and gestational age were significant risk factors for NI.

CONCLUSION

Our data do not support the hypothesis that early NP increases the risk for NI in VLBW infants.

Granulocyte-macrophage colony stimulating factor administered as prophylaxis for reduction of sepsis in extremely preterm, small for gestational age neonates (the PROGRAMS trial): a single-blind, multicentre, randomised controlled trial

BACKGROUND

Systemic sepsis is a major cause of death in preterm neonates. There are compelling theoretical reasons why treatment with haemopoietic colony-stimulating factors might reduce sepsis and improve outcomes, and as a consequence these agents have entered into use in neonatal medicine without adequate evidence. We assessed whether granulocyte-macrophage colony stimulating factor (GM-CSF) administered as prophylaxis to preterm neonates at high risk of neutropenia would reduce sepsis, mortality, and morbidity.

METHODS

We undertook a single-blind, multicentre, randomised controlled trial in 26 centres between June, 2000, and June, 2006. 280 neonates of below or equal to 31 weeks' gestation and below the 10th centile for birthweight were randomised within 72 h of birth to receive GM-CSF 10 microg/kg per day subcutaneously for 5 days or standard management. From recruitment to day 28 a detailed daily clinical record form was completed by the treating clinicians. Primary outcome was sepsis-free survival to 14 days from trial entry. Analysis was by intention to treat. This study is registered as an International Standard Randomised Controlled Trial, number ISRCTN42553489.

FINDINGS

Neutrophil counts after trial entry rose significantly more rapidly in infants treated with GM-CSF than in control infants during the first 11 days (difference between neutrophil count slopes 0.34 x 10(9)/L/day; 95% CI 0.12-0.56). There was no significant difference in sepsis-free survival for all infants (93 of 139 treated infants, 105 of 141 control infants; difference -8%, 95% CI -18 to 3). A meta-analysis of this trial and previous published prophylactic trials showed no survival benefit.

INTERPRETATION

Early postnatal prophylactic GM-CSF corrects neutropenia but does not reduce sepsis or improve survival and short-term outcomes in extremely preterm neonates.

Dysfunction of innate immunity and associated pathology in neonates

The neutrophils and complement system are the critical elements of innate immunity mainly due to participation in the first line of defense against microorganisms by means of phagocytosis, lysis of bacteria and activation of naive B-lymphocytes. In this report we provide an overview of the up to date information regarding the neutrophil and complement system's functional ability in newborn infants in association with the maternal conditions that exist during the intrauterine stage, gestational age and post-neonatal pathology. The neonates' capacity to control the neutrophil and complement protein activation process has also been discussed because of the evidence that uncontrolled activation of these immune elements provides a significant contribution to the tissue damage and subsequent pathology. The authors are confident that despite the many unanswered questions this review updates their knowledge and points the need for further research to clarify the role of the age-associated dysfunction of neutrophils and complement system in the infection and inflammation related pathology of newborn infants.

Low blood neutrophil concentrations among extremely low birth weight neonates: data from a multihospital health-care system

OBJECTIVE

A blood neutrophil concentration < 1000/microl has been reported to occur in about 8% of neonatal intensive care unit (NICU) patients, at some time during their hospital stay. However, the incidence of this finding among extremely low birth weight (ELBW) neonates (< 1000 g birth weight) is not known. Using data from four NICU's in one health-care system, we sought to estimate the incidence, timing, causes, severity and duration of neutrophil counts < 1000/microl among ELBW neonates. We also tabulated the treatments used for this condition and associations with mortality.

METHODS

We performed an historic cohort analysis of all ELBW neonates born during the 36-month period, 1 July 2002 to 30 June 2005, cared for in the four Intermountain Healthcare level III NICU's.

RESULTS

Three hundred and thirty-eight ELBW neonates were the subjects of the analysis. Complete blood cell counts (CBCs) were obtained in all (range, 1 to 123 CBCs/patient). Thirty-eight percent (128/338) had one or more neutrophil counts < 1000/microl. In 57% the low neutrophil count persisted for < 24 h; in 43% it persisted for 1 to 7.5 days. Most of the cases (74%) were detected during the first 3 days of life. Twenty-two percent of cases were not detected until after the first week. Low neutrophil counts were more common among the smallest patients, with a 63% incidence in those < or = 500 g, 44% in those 501 to 600 g and 34% in those 801 to 999 g. When low neutrophil counts were recognized during the first 3 days of life, the patients were typically either small for gestational age (SGA; weight < 10th percentile for gestational age) or born after pregnancy-induced hypertension (PIH) (68%), or had early-onset bacterial infection (6%). When recognized after the first 3 days, the patients typically had necrotizing enterocolitis (31%) or a nosocomial bacterial infection (19%). Alloimmune mechanisms were not tested for in any of the cases. No cause for the low counts was identified among 35% of the neutropenic patients. Intravenous immunoglobulins was administered to 28% of cases, and 100% of these were given according to our written guidelines. Recombinant granulocyte-colony stimulating factor was administered to 13% of cases, and 69% of these were given according to guidelines. Neither the presence of low neutrophil counts nor the severity (lowest recorded count) correlated with mortality rate, except in proven early-onset sepsis.

CONCLUSIONS

We observed low neutrophil counts among ELBW neonates at a rate five times that reported in the general NICU population. Most cases were present in the first days of life and occurred in SGA neonates or those with PIH. In over 1/3, no cause was discovered. We maintain that more consistency is needed in evaluating and treating neutropenia among ELBW neonates.

Toward improving mucosal barrier defenses: rhG-CSF plus IgG antibody

Epithelial cell functions ultimately define the ability of the extremely low birth weight human fetus to survive outside of the uterus. These specialized epithelial cell capacities manage all human interactions with the ex utero world including: (i) lung mechanics, surface chemistry and gas exchange, (ii) renal tubular balance of fluid and electrolytes, (iii) barrier functions of the intestine and skin for keeping bacteria out and water in, plus enabling intestinal digestion, as well as (iv) maintaining an intact neuroepithelium lining of the ventricles of the brain and retina. In Part I of this two part review, the authors describe why the gut barrier is a clinically relevant model system for studying the complex interplay between innate and adaptive immunity, dendritic &epithelial cell interactions, intraepithelial lymphocytes, M-cells, as well as the gut associated lymphoid tissues where colonization after birth, clinician feeding practices, use of antibiotics as well as exposure to prebiotics, probiotics and maternal vaginal flora all program the neonate for a life-time of immune competence distinguishing "self" from foreign antigens. These barrier defense capacities become destructive during disease processes like necrotizing enterocolitis (NEC) when an otherwise maturationally normal, yet dysregulated and immature, immune defense system is associated with high levels of certain inflammatory mediators like TNFa. In Part II the authors discuss the rationale for why rhG-CSF has theoretical advantages in managing NEC or sepsis by augmenting neonatal neutrophil number, neutrophil expression of Fcg and complement receptors, as well as phagocytic function and oxidative burst. rhG-CSF also has potent anti-TNFa functions that may serve to limit extension of tissue destruction while not impairing bacterial killing capacity. Healthy, non-infected neutropenic and septic neonates differ in their ability to respond to rhG-CSF; however, no neonatal clinical trials to date have identified a clear clinical benefit of rhG-CSF therapy. This manuscript will review the literature and evidence available for identifying the ideal subject for cytokine treatment using NEC as the model disease target.

Dysregulation of Expression of Immunoregulatory and Cytokine Genes and Its Association with the Immaturity in Neonatal Phagocytic and Cellular Immunity

BACKGROUND

Innate and adaptive immunity is comprised of cellular and humoral factors that provide rapid protection against microbial invasion. However, immaturity of innate and adaptive immune responses in the perinatal period predisposes the neonate to increased infectious morbidity and mortality from a variety of organisms.

OBJECTIVES

To elucidate dysregulation of expression of various immunoregulatory and cytokine genes and its association with the immaturity in neonatal phagocytic cellular immunity.

METHODS

Comparison of protein production and mRNA of granulocyte macrophage colony-stimulating factor (GM-CSF), macrophage colony-stimulating factor (M-CSF), granulocyte colony-stimulating factor (G-CSF), interleukin (IL)-12, IL-15 and IL-18 in adult peripheral blood (APB) mononuclear cells (MNC) and cord blood (CB) MNC was studied. Effects of hematopoietic growth factors (HGFs, GM-CSF, M-CSF, G-CSF, IL-11) were studied in vivo in rats as well as randomized controlled studies conducted in neonates. Oligonucleotide microarrays were used to study gene expression patterns of activated CB and APB monocytes and dendritic cells.

RESULTS AND CONCLUSIONS

We demonstrated dysregulation of various immunoregulatory and cytokine genes in CB MNC. This dysregulation may in part explain the immaturity of neonatal cell-mediated immunity. There are probably various dysregulated cytokines yet to be discovered. Biological agents such as IL-2, IL-12, IL-11 and/or IL-18 alone or in combination with HGFs should be considered for future studies to identify new approaches to enhance neonatal host defense, and thereby decrease the incidence of neonatal sepsis and the consequent high risk of morbidity and mortality.

Granulocyte colony-stimulating factor and granulocyte-macrophage colony-stimulating factor have differential effects on neonatal and adult neutrophil survival and function

Neutropenia is a common sequela of neonatal sepsis. Recent clinical trials have shown the beneficial effects of colony-stimulating factors (CSFs) on outcome in this group, but the exact mechanism remains unknown. Neonates and mothers who were at high-risk for infection were recruited for cord blood sampling in a university tertiary referral maternity hospital. Neonatal and adult neutrophils were evaluated for their ability to combat bacterial infection by examining their functional activity (CD11b and reactive oxygen intermediates) and their persistence at inflammatory sites (apoptosis). The mechanism for altered apoptotic responses was assessed by caspase activation assays, X chromosome-linked inhibitor of apoptosis protein expression, and cytosolic cytochrome c release. Although granulocyte colony-stimulating factor (G-CSF) and granulocyte-macrophage colony-stimulating factor (GM-CSF) significantly delayed neutrophil apoptosis in normal adults, only G-CSF had a similar effect in normal neonates. Neutrophils from neonates who are at high risk for infection are unresponsive to the antiapoptotic effects of G-CSF or GM-CSF, unlike maternal neutrophils, which have delayed apoptosis in response to GM-CSF. However, CD11b expression and reactive oxygen intermediate production were significantly increased in normal neonatal neutrophils that were incubated with GM-CSF versus controls but not G-CSF or lipopolysaccharide. Decreased cytosolic cytochrome c release and caspases 3 and 9 activity are associated with the CSF-mediated delay in apoptosis in adults but not in newborns. The antiapoptotic X chromosome-linked inhibitor of apoptosis protein is up-regulated in neonates compared with adults and may mediate their differential spontaneous apoptosis. These results have important implications for the use of CSFs in neonatal sepsis, as responses differ from those seen in adults. Further delineation of neonatal neutrophil responses to CSFs may improve their therapeutic potential.

Practice variation in suspected neonatal sepsis: a costly problem in neonatal intensive care

OBJECTIVE

The most common admission to intensive care nurseries is the infant with suspected neonatal sepsis. To determine the clinical practice of neonatologists with respect to this diagnosis, we examined a large neonatal database during a 2-year period of time. The goal of this study was to define whether there were optimal practice strategies that could identify a "benchmark" clinical approach for this diagnosis.

DESIGN

The PROACT database of ParadigmHealth was examined for all term infants with an admitting ICD - 9 code for suspected neonatal sepsis between January 1, 2001 and December 31, 2002. Infants had to be asymptomatic by 24 hours of life with no significant respiratory signs and receiving oral feedings. All infants had negative blood cultures. Maternal risk factors were examined to determine if they influenced the duration of therapy. The impact of treatment upon subsequent length of stay was also evaluated. Several areas of the country were individually examined to see if possible regional variations existed with respect to treatment of suspected sepsis.

RESULTS

There were no significant differences noted in the management when maternal risk factors for suspected sepsis were assessed. In general, neonates were treated for 3.3+/-1.8 to 3.5+/-2.1 days, regardless of the number of maternal risk factors present at birth (p=NS). Length of stay ranged from 4.2+/-2.1 to 4.4+/-1.9 days in these groups (p=NS). The duration of treatment ranged from 1 to 10 days, even though all infants were clinically well and feeding by 24 hours of life. A total of 170 infants (17.0%) were treated for 4 to 6 days and 116 (11.6%) neonates received antibiotics for 7 to 10 days, even with negative blood cultures. One region of the country appeared to treat infants for a longer period of time than the other four regions examined, increasing the mean length of stay by 1.8 days (p<0.05).

CONCLUSIONS

Treatment of neonates with suspected sepsis appears to be influenced by considerations other than maternal risk factors or the infant's clinical condition beyond the first day of life. There appears to be a great deal of practice variation among neonatologists confronted by patients with suspected sepsis. Awareness of this unnecessary variation may be of great value in reducing the duration of antibiotic therapy in the NICU and shortening the length of stay.

Clinical microbiology of bacterial and fungal sepsis in very-low-birth-weight infants

Twenty percent of very-low-birth-weight (<1500 g) preterm infants experience a serious systemic infection, and despite advances in neonatal intensive care and antimicrobials, mortality is as much as threefold higher for these infants who develop sepsis than their counterparts without sepsis during their hospitalization. Outcomes may be improved by preventative strategies, earlier and accurate diagnosis, and adjunct therapies to combat infection and protect the vulnerable preterm infant during an infection. Earlier diagnosis on the basis of factors such as abnormal heart rate characteristics may offer the ability to initiate treatment prior to the onset of clinical symptoms. Molecular and adjunctive diagnostics may also aid in diagnosing invasive infection when clinical symptoms indicate infection but no organisms are isolated in culture. Due to the high morbidity and mortality, preventative and adjunctive therapies are needed. Prophylaxis has been effective in preventing early-onset group B streptococcal sepsis and late-onset Candida sepsis. Future research in prophylaxis using active and passive immunization strategies offers prevention without the risk of resistance to antimicrobials. Identification of the differences in neonatal intensive care units with low and high infection rates and implementation of infection control measures remain paramount in each neonatal intensive care unit caring for preterm infants.

In vivo effect of recombinant human granulocyte colony-stimulating factor on phagocytic function and oxidative burst activity in septic neutropenic neonates

Neutrophil dysfunction may contribute to an increased risk of sepsis in very-low-birth-weight (VLBW) neonates. The current study was designed to determine whether recombinant human granulocyte colony-stimulating factor (rhG-CSF) affects absolute neutrophil count (ANC), phagocytic function, and oxidative burst in neutropenic VLBW neonates. Fourteen ventilated VLBW neonates were treated with rhG-CSF (10 microg/kg/day x 3 days i.v.). Phagocytic activity and oxidative burst were assessed before and after treatment with rhG-CSF using flow cytometry and fluorescence labeled opsonized Staphylococcus aureus. Control (nonseptic, nonneutropenic, n = 4), preeclamptic neutropenic (PET; nonseptic, n = 5), and septic neutropenic (n = 5) neonates with a gestational age ranging from 24 to 30 weeks were studied. In both PET and septic neonates, posttreatment phagocytosis more than doubled, but did not achieve matching control levels, whereas rhG-CSF treatment maintained the level of the phagocytic activity in the control group. The oxidative burst increased in all groups, but, again, PET and septic groups did not achieve matching control values. These effects occurred independent of a 2- to 12-fold increase in ANC. These results suggest that other disease-specific factors delay full functional recovery even after rhG-CSF treatment. We speculate that PET and septic neonates may remain susceptible to infection due to deficient neutrophil-killing capacity, even though their ANC returns to normal ranges. Augmenting immune function beyond the immediate period of ANC recovery suggests that prophylaxis with rhG-CSF may be an important risk reduction strategy for susceptible VLBW neonates.

Neonatal neutrophils: the good, the bad, and the ugly

Neonates are at considerable risk for bacterial and fungal infections,due in great part to a variety of age-related impairments in neutrophil function. In addition, evidence suggests that the tendency of the most immature neonates to develop chronic inflammatory disorders is also related to neutrophil dysfunction. This article provides an overview of specific functional deficiencies of neutrophils that have been reported in neonates.

Haemopoietic growth factors for neonates: assessing risks and benefits

This review summarises the rationale, clinical trial evidence for benefit and potential toxicities of Erythropoietin, Thrombopoietin, Granulocyte Colony Stimulating Factor and Granulocyte-Macrophage Colony Stimulating Factor. Erythropoietin has failed to have a clinical impact on red cell transfusion requirement in very low birth weight infants; it is uncertain whether Thrombopoietin will find a significant clinical role in neonatal thrombocytopenia and there is, as yet, insufficient evidence for the routine use of Granulocyte- or Granulocyte-Macrophage Colony Stimulating Factor to prevent or treat bacterial infection. A number of theoretical risks of haemopoietic growth factor use in neonates have been suggested, but no toxicities have been observed during their clinical use. Exploring the potential for benefit in selected groups of infants should be encouraged.

Effect of recombinant granulocyte colony-stimulating factor on blood neutrophil concentrations among patients with "idiopathic neonatal neutropenia": a randomized, placebo-controlled trial

OBJECTIVES

We previously described a severe, prolonged, idiopathic, but self-resolving, variety of neutropenia among preterm neonates. In the present study, we sought to assess the marrow neutrophil reserves of these patients by serially measuring blood neutrophils following the administration of recombinant granulocyte colony-stimulating factor (rG-CSF) or placebo.

STUDY DESIGN

Prospective, randomized trial of rG-CSF vs placebo for infants with "idiopathic neonatal neutropenia".

RESULTS

During 36 consecutive months, 2407 neonates were admitted to the neonatal intensive care unit; 429 weighed less than 1500 g at birth, 14 of these were later diagnosed with "idiopathic neonatal neutropenia"; 10 were enrolled in this trial. The five rG-CSF recipients had an immediate, marked increase in blood neutrophil concentration, indicating adequate rG-CSF-mobilizable marrow neutrophil reserves. This effect persisted to day 5, but counts were not different from those of the five placebo recipients on days 12 and 15.

CONCLUSIONS

Patients with "idiopathic neonatal neutropenia" have a substantial rG-CSF-mobilizable marrow neutrophil reserve. On that basis, we speculate that this variety of neonatal neutropenia does not constitute a significant deficiency in antibacterial defense.

Late-onset neutropenia in very low birthweight infants

AIM

To evaluate the incidence and duration of late-onset neutropenia (defined as an absolute neutrophil count (ANC) <1500 mm(-3) at a postnatal age of >3 wk) in a population of infants with birthweight <2000 g, and to determine whether copper deficiency, a possible cause of both anemia and neutropenia, may be associated with this complication.

METHODS

Complete blood cell count and differential were assessed in 247 low (LBW) and very low birthweight (VLBW) infants who were discharged after 3 wk of life. In neutropenic infants plasma copper and ceruloplasmin levels were also measured.

RESULTS

Late-onset neutropenia was detected in 11 out of 147 VLBW infants (7.5%) and in 7 out of 127 LBW infants (5.5%). A neutrophil count of <1000 mm(-3) was observed in 14 infants (5.1%). A significantly lower gestational age was found in neutropenic infants compared with non-neutropenic infants. In neutropenic infants ANCs were significantly correlated with hemoglobin and hematocrit. In addition, a significant negative correlation was found between neutrophil and reticulocyte counts. Plasma copper concentration was significantly correlated with birthweight. Oral copper sulfate was administered to infants with plasma copper concentration <50 microg dl(-1), and did not seem to affect ANC, hemoglobin, hematocrit or reticulocyte counts.

CONCLUSION

Late-onset neutropenia appears to be a benign condition that is not associated with any particular complication and does not require specific treatment. Reference ranges after the early neonatal period and during the first few months of life in LBW and VLBW infants should probably be set at lower values.

What is the rationale for the use of granulocyte and granulocyte-macrophage colony-stimulating factors in the neonatal intensive care unit?

Neonatal sepsis remains an unsolved major contributor to morbidity and mortality. In the 1980s the promise of augmenting immune function using pooled intravenous gammaglobulin to supplement the exceedingly low levels of immunoglobulin G in premature infants failed to demonstrate a clear advantage. Similarly, cytokine augmentation of cellular function in the 1990s largely appeared to be suffering the same fate. However, both results may arise from a problem in experimental design where the combination of both treatments may be necessary along with specific antibody. For example, in vitro, independently of an array of other humoral and cellular immature immune system issues, opsonization of bacteria is improved in the presence of antibody. The question is whether the same result can be achieved in vivo. No experiments have been reported that directly test this hypothesis.

CONCLUSION

More investigation is needed in this challenging area of neonatal research.

G-CSF and GM-CSF for treating or preventing neonatal infections

BACKGROUND

The colony stimulating factors (CSFs), granulocyte-macrophage colony stimulating factor (GM-CSF) and granulocyte colony stimulating factor (G-CSF), are naturally occurring cytokines that stimulate the production and antibacterial function of neutrophils and monocytes. Two strategies have been adopted for exploring whether CSFs can provide clinical benefit for preterm infants. The first has investigated their use as a treatment to improve outcome in established systemic infection, especially when complicated by a low neutrophil count. The alternative strategy has been to use CSFs prophylactically, to prevent sepsis prospectively through stimulation of neutrophil production and bactericidal function.

OBJECTIVES

To determine the efficacy and safety of the haemopoietic colony stimulating factors (G-CSF or GM-CSF) in newborn infants, when used for:a) treatment of suspected or proven systemic infection to reduce mortality, orb) prophylaxis, to prevent systemic infection in infants at high risk of nosocomial infection. To determine, in subgroup analysis, the influence of pre-existing or high risk of neutropenia on the outcome of therapy.

SEARCH STRATEGY

PubMed, EMBASE, MEDLINE and the Cochrane Central Register of Controlled Trials (The Cochrane Library, Issue 2, 2003) were searched in April 2003 using the keywords: G-CSF, GM-CSF, infant newborn, with and without the limit Clinical Trial. In addition, reference lists of identified RCTs, meta-analyses and personal files were searched.

SELECTION CRITERIA

The criteria used to select studies for inclusion were:

DESIGN

RCT.

SUBJECTS

Newborn infants in intensive care.

INTERVENTIONS

G-CSF or GM-CSF given as treatment in conjunction with antibiotics for suspected or microbiologically proven systemic infection. G-CSF or GM-CSF given as prophylaxis with the aim of reducing the incidence of systemic infection.

OUTCOMES

Treatment studies reporting all cause mortality. Prophylaxis studies reporting subsequent incidence of sepsis and / or mortality.

DATA COLLECTION AND ANALYSIS

Relative risks (RR) and risk differences (RD) with 95% confidence intervals (CI) using the fixed effect model are reported. Number needed to treat (NNT) was calculated for the outcomes that showed a statistically significant reduction in RR.

MAIN RESULTS

Seven treatment studies of 257 infants with suspected systemic bacterial infection and three prophylaxis studies comprising 359 neonates are analysed. Treatment studies: There is no evidence that the addition of G-CSF or GM-CSF to antibiotic therapy in preterm infants with suspected systemic infection reduces immediate all cause mortality. No significant survival advantage was seen at 14 days from the start of therapy [typical RR 0.71 (95% CI 0.38,1.33); typical RD -0.05 (95% CI -0.14, 0.04)]. However all seven of the treatment studies were small, the largest recruiting only 60 infants. The subgroup analysis of 97 infants from three treatment studies who, in addition to systemic infection, had clinically significant neutropenia (< 1.7 x 10(9)/l) at trial entry, does show a significant reduction in mortality by day 14 [RR 0.34 (95% CI 0.12, 0.92); RD -0.18 (95% CI -0.33, -0.03); NNT 6 (95% CI 3-33)]. Prophylaxis studies have not demonstrated a significant reduction in mortality in neonates receiving GM-CSF [RR 0.59 (95% CI 0.24,1.44); RD -0.03 (95% CI -0.08,0.02)]. The identification of sepsis as the primary outcome of prophylaxis studies has been hampered by inadequately stringent definitions of systemic infection. However, data from one study suggest that prophylactic GM-CSF may provide protection against infection when given to preterm infants who are neutropenic or at high risk of developing postnatal neutropenia.

REVIEWER'S CONCLUSIONS

There is currently insufficient evidence to support the introduction of either G-CSF or GM-CSF into neonatal practice, either as treatment of established systemic infection to reduce resulting mortality, or as prophylaxis to prevent systemic infection in high risk neonates. No toxicity of CSF use was reported in any systemic infection to reduce resulting mortality, or as prophylaxis to prevent systemic infection in high risk neonates. No toxicity of CSF use was reported in any study included in this review. The limited data suggesting that CSF treatment may reduce mortality when systemic infection is accompanied by severe neutropenia should be investigated further in adequately powered trials which recruit sufficient infants infected with organisms associated with a significant mortality risk.

Idiopathic, immune, infectious, and idiosyncratic neutropenias

In idiopathic and immune neutropenias the susceptibility to infectious agents is highly variable, but the reason why some patients exhibit no undue susceptibility whereas others contract life-threatening infections is poorly understood. An important factor is the efficacy of delivery of neutrophils to the tissues. Recent investigations of the mechanisms for mild to moderate chronic neutropenias have shown the significance of interactions between myelopoiesis and the immune system, as for example, in relation to immunoglobulin aberrations and the cytokine network. Antibody-mediated neutropenias (alloimmune, autoimmune) are now well-characterized diseases. If infections occur, apart from antibiotics, granulocyte colony-stimulating factor (G-CSF) is the treatment of choice, while intravenous or monoclonal immunoglobulins and cyclosporine are reserved for refractory cases.

A trial of recombinant human granulocyte colony stimulating factor for the treatment of very low birthweight infants with presumed sepsis and neutropenia

OBJECTIVES

The primary objective was to investigate the safety of recombinant human granulocyte colony stimulating factor (rhG-CSF) for the treatment of very low birthweight infants (VLBW) with sepsis and relative neutropenia, specifically with regard to worsening of respiratory distress and thrombocytopenia and all cause mortality. Secondary objectives were to evaluate duration of ventilation, intensive care, and antibiotic use as markers of efficacy.

DESIGN

Neonates (< or = 28 days) in intensive care, with birth weights of 500-1500 g, absolute neutrophil count (ANC) of < or = 5 x 10(9)/l, and clinical evidence of sepsis, were randomly assigned to receive either rhG-CSF (10 microg/kg/day) administered intravenously (n = 13), or placebo (n = 15) for a maximum of 14 days, in addition to standard treatment and antibiotics. All adverse events, oxygenation index, incidence of thrombocytopenia, all cause mortality, duration of ventilation, intensive care and antibiotic treatment, and ANC recovery were compared between the two groups.

RESULTS

Adverse events and oxygenation index were not increased by, and thrombocytopenia was not attributable to, treatment with rhG-CSF. At 6 and 12 months postmenstrual age, there were significantly fewer deaths in the group receiving rhG-CSF (1/13 v 7/15; p < or = 0.038). There was a non-significant trend towards a reduction in duration of ventilation, intensive care, and antibiotic use in the rhG-CSF group. There was a significantly more rapid increase in ANC in the rhG-CSF treated babies (p < 0.001).

CONCLUSIONS

In a small randomised placebo controlled trial in a highly selected group of neonates, adjuvant treatment with rhG-CSF increased ANC rapidly, and no treatment related adverse events were identified. Mortality at 6 and 12 months postmenstrual age was significantly lower in the treatment group. A large trial investigating efficacy in a similar group of neonates is warranted.

Late-onset neutropenia in very low birth weight infants

BACKGROUND

Neutropenia, defined as absolute neutrophil count (ANC) <1500/mm(3), affects 6% to 58% of premature infants in the first week of life. This early-onset neutropenia in premature infants has previously been correlated with sepsis, maternal hypertension, severe asphyxia, and periventricular hemorrhage. Late-onset neutropenia, defined as ANC <1500/mm(3) at a postnatal age of >/=3 weeks, has not been previously reported.

OBJECTIVES

The purposes of this study were to determine the prevalence of late-onset neutropenia in very low birth weight (VLBW) infants and to examine the factors that may be associated with this phenomenon.

METHODS

A weekly complete blood cell count (CBC) was performed routinely in all premature infants with birth weight </=1500 g (n = 225) admitted to the neonatal intensive care in a 3-year period who survived until discharge. CBC and differentials were recorded at day 1, day 3, and then weekly until discharge. The clinical data of the study infants were collected by reviewing the medical records retrospectively.

RESULTS

Late-onset neutropenia was detected in 51 infants (22%). In both neutropenic (n = 51) and nonneutropenic infants (n = 174), ANC increased postnatally, remained above 5000/mm(3) for the first 3 weeks of life, and had a marked decrease at approximately 4 weeks of age. Thereafter, ANC decreased to a level of approximately 1400/mm(3) in the neutropenic infants and 4000/mm(3) in the nonneutropenic infants. The neutropenic infants had a significantly lower nadir ANC, lower hemoglobin, and higher reticulocyte count than did the nonneutropenic infants with similar platelet counts. None of the study infants received erythropoietin during their hospitalization. This late-onset neutropenia occurred at postnatal age of 6 +/- 2 weeks (range: 3-10 weeks). The duration of neutropenia was 1.7 +/-.7 weeks (range: 1-3 weeks). All of the neutropenic infants had anemia of prematurity with high reticulocyte count and normal platelet count. The neutropenic infants were stable, growing on full oral feedings, and had no signs or symptoms of sepsis. No adverse effects of late-onset neutropenia were apparent in these infants.

CONCLUSION

Late-onset neutropenia is a common incidental finding in stable, growing VLBW infants that has not been previously reported. Late-onset neutropenia is a phenomenon that occurs in anemic premature infants who have marked reticulocytosis. Normal regulation of hematopoiesis is accompanied by a balance between colony-stimulating factors, such as erythropoietin and granulocyte colony-stimulating factor, which regulate erythropoiesis and granulopoiesis. We speculate that imbalance of these factors with increased reticulocytopoiesis in response to anemia of prematurity may explain this phenomenon. We recommend avoiding institution of aggressive, potentially harmful therapy for this phenomenon in healthy, growing VLBW infants.

A practical approach to evaluating and treating neutropenia in the neonatal intensive care unit

Neutropenia is a relatively common problem in the NICU, recognized in as many as 8% of patients at some time during their hospital stay. In most instances, neutropenia among NICU patients is of short duration and has little influence on outcome. In other cases it is prolonged and severe, and constitutes a serious antimicrobial defense deficiency. When a neonatologist discovers a low blood neutrophil count, choices must be made regarding further evaluation and treatment. The authors hope that the information provided in this article is useful in making these choices.

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.

Neonatal alloimmune neutropenia in premature monozygous twins

Alloimmune neonatal neutropenia (ANN) is an uncommon but potentially life-threatening disorder of the neonate and young infant. Hematologically, the mother's peripheral neutrophil count is normal. However, the passive transfer of maternal immunoglobulin G neutrophil-specific antibodies and the subsequent sensitization of fetal neutrophils can result in severe neutropenia in the neonate. Generally, ANN is a self-limiting condition, but with severe bacterial infection, mortality can be high. We present the clinical features of monozygous twins delivered at 33 weeks' postconception with this condition. This case report is unique in that it occurred in twins born prematurely and was attributable to antibodies against 2 neutrophil-specific antigens, NA1 and NB1. A brief review of the diagnosis, management, and treatment of ANN is presented.

Improving the outcome of septic shock in children

Sepsis is an important cause of pediatric morbidity and mortality. Improving the outcome of pediatric sepsis requires diverse efforts, including prevention, early recognition, improvements in early management and transport, and physiology-directed care. Awareness that septic shock represents a pathophysiologic host response to infection has prompted investigation of immune mediators and coagulation factors as potential targets for anti-sepsis therapies. Advancements thus far include: the potential prevention of neonatal sepsis with granulocyte colony-stimulating factor; recognition of clindamycin as a potential inhibitor of endotoxin release; improved outcome from meningococcal disease in children treated with bactericidal/permeability-increasing protein (rBPI21); and improved outcome from sepsis in premature infants treated with pentoxifylline. Further randomized controlled studies of immunomodulatory agents are indicated and a few are in progress. Current studies on genetic propensities in cytokine and coagulation protein expression may explain variability in patient outcomes and eventually lead to genomics-based therapeutics.

Decreased mRNA expression of G-CSF receptor in cord blood neutrophils of term newborns: regulation of expression by G-CSF and TNF-alpha

Granulocyte colony-stimulating factor (G-CSF) promotes neutrophil production and enhances neutrophil function. The effects of G-CSF are mediated by binding to its receptor. Since neutrophils are an essential part of the neonatal host defense system, we studied G-CSF receptor expression in neonatal neutrophils. We determined protein and mRNA expression of G-CSF receptor in freshly isolated neutrophils from cord blood of healthy term newborns (n = 16) and of adults (n = 6) as well as the in vitro effect of supplemented recombinant human G-CSF (rhG-CSF) and tumor necrosis factor-alpha (TNF-alpha) on G-CSF receptor expression of neutrophils. Expression of G-CSF receptor on the surface of neutrophils of cord blood was significantly lower compared to adults (61 +/- 6 vs. 89 +/- 2%). G-CSF receptor mRNA transcripts of neutrophils from newborns compared to adults was lower, too (77 +/- 14 vs. 152 +/- 33%). Neutrophils isolated from cord blood showed a decrease of G-CSF receptor expression within 24 h of culture. Moreover, we were able to show that supplemented rhG-CSF is necessary for maintenance of G-CSF receptor expression. TNF-alpha, however, down-regulated G-CSF receptor expression. We conclude that low protein and mRNA expression of G-CSF receptor in neutrophils of neonates compared to adults may adversely affect granulopoiesis and neutrophil functions by decreased responsiveness to G-CSF. Furthermore, G-CSF receptor expression on neutrophils was modified not only by G-CSF itself, but also by TNF-alpha.

Granulocyte colony-stimulating factor serum and urine concentrations in neutropenic neonates before and after intravenous administration of recombinant granulocyte colony-stimulating factor

BACKGROUND

Recombinant granulocyte colony-stimulating factor (rG-CSF) has been suggested as a treatment for certain varieties of neonatal neutropenia, but little is known about the pharmacologic disposition of rG-CSF in that population.

METHODS

Ten neutropenic neonates were treated with rG-CSF, 10 micrograms/kg intravenously once daily for 3 to 5 days. Serum and urine samples were obtained before rG-CSF dosing and at intervals thereafter for G-CSF quantification by enzyme-linked immunosorbent assay.

RESULTS

Five of the neutropenic neonates (termed group 1) were not infected but likely had hyporegenerative neutropenia (4 were born after pregnancy-induced hypertension/intrauterine growth restriction, and 1 had Rh hemolytic disease). Five other infants (group 2) had neutropenia accompanying bacterial sepsis and shock. Before receiving the first dose of rG-CSF, endogenous G-CSF serum and urine concentrations were relatively low in group 1, averaging 130 pg/mL (range: 48-209) in serum and 53 pg/mL (range: 15-141) in urine. Serum concentrations immediately before the final dose were much higher (range: 81-24 835 pg/mL), whereas urine concentrations were unchanged (range: <7 pg/mL-126 pg/mL). In group 2 patients, before receiving the first-dose of rG-CSF, endogenous concentrations were very high, averaging 59 575 pg/mL (range: 20 028-98 280) in serum and 3189 pg/mL (range: 23-4770) in urine. Predose serum concentrations before the final dose (range: 427-14 460 pg/mL) were lower than before the first dose. The area under the concentration curve after the first dose of rG-CSF administration in group 1 was significantly lower than after the first dose in group 2, but no difference in area under the concentration curve was observed between groups 1 and 2 after the last dose of rG-CSF.

SPECULATION

The principal means of clearing G-CSF from the serum is by saturable binding to specific G-CSF receptors (G-CSF-Rs). Therefore, the very high G-CSF serum and urine concentrations of group 2 patients before the first rG-CSF dose implies that their G-CSF-Rs were saturated before the dose was given. We speculate that if G-CSF-Rs are saturated with endogenous G-CSF, treatment with rG-CSF will add little or nothing to the granulocytopoietic effort. On this basis, we judge that neonates with septic shock and neutropenia are unlikely to derive benefit from rG-CSF administration.

Distribution of granulocyte colony-stimulating factor (G-CSF) and G-CSF-receptor mRNA and protein in the human fetus

Granulocyte colony-stimulating factor (G-CSF) promotes neutrophil proliferation, differentiation, and survival. It acts by binding to specific cell-surface receptors (G-CSF-R), which are expressed on cells of granulocytic lineage, human endothelial cells, and placenta. It has been postulated that the administration of recombinant G-CSF (rG-CSF) to preterm neonates might be useful in treating infections or in reducing nosocomial infections. Whereas it is known that G-CSF and G-CSF-R are present in the developing fetal bone marrow and liver, no information is available as to the existence or distribution of nonhematopoietic G-CSF-R in other tissues of the developing human fetus. We hypothesized that G-CSF and its receptor might be expressed in various fetal tissues, as has been shown for other growth factors such as erythropoietin and fibroblast growth factor. Therefore, we studied the anatomical distribution of mRNA-encoding G-CSF and G-CSF-R, using RT-PCR and in situ RT-PCR in a variety of human fetal tissues ranging from 8 to 24 weeks postconception. The cellular distributions of the corresponding proteins were determined by immunohistochemistry. Both G-CSF and G-CSF-R were present in nearly every organ and tissue examined, but in discrete cellular localizations. G-CSF-R in kidney and intestine underwent changes in anatomical distribution with fetal development. These results indicate that G-CSF and G-CSF-R have wide anatomical expression in the developing human fetus.

Colony-Stimulating Factors in the Therapeutic Approach to Sepsis

Sepsis and its complications continue to be a leading cause of death in the United States despite availability of potent broad-spectrum antimicrobial agents. Current in vitro, ex vivo, animal, and human data are reviewed. Present data shows that colony-stimulating factors (CSFs), granulocyte CSFs, and granulocyte-macrophage CSFs are very effective in raising the leukocyte count and shortening the number of neutropenic days. CSFs in some studies improved outcome of neutropenic septic patients especially when given very early. However, there are studies that do not show any benefit. CSFs appear to be safe and should be limited to septic, neutropenic patients whose duration of neutropenia is anticipated to be prolonged, or to patients who are seriously ill.

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.

A randomized, controlled trial of prophylactic granulocyte-macrophage colony-stimulating factor in human newborns less than 32 weeks gestation

OBJECTIVE

Preterm neonates undergoing intensive care have high morbidity from sepsis. These infants also frequently develop neutropenia, and when this is associated with sepsis, mortality is high. This study investigates the potential for granulocyte-macrophage colony-stimulating factor (GM-CSF) to effect a clinically relevant increase in neutrophil number when used prophylactically in high-risk preterm neonates, and assesses its safety in this population.

DESIGN

In an open, randomized, controlled study, 75 neonates (25 small for gestational age) <32 weeks gestation were randomized to receive GM-CSF (10 microg/kg/d) by subcutaneous injection for 5 days from <72 hours after birth, or to a control group. The primary outcome measure was the neutrophil count during 14 days from study entry. The infants were monitored for potential toxicity. Clinical outcomes, sepsis, and mortality, were recorded, but this initial study was not designed to address clinical benefit.

RESULTS

Prophylactic GM-CSF therapy completely abolished neutropenia in treated infants, when both well and septic, throughout the period of study. Neutropenia (</=1.7 x 10(9)/L) developed in 16 of 39 control infants. Five control infants experienced an acute decrease in neutrophil count coincident with the onset of sepsis. There was no evidence of hematologic, respiratory, or gastrointestinal toxicity in treated infants. Treated infants had a trend to fewer symptomatic, blood culture positive septic episodes than controls during 2 weeks from study entry (11/36 vs 18/39).

CONCLUSION

Five-day prophylactic GM-CSF completely abolishes postnatal neutropenia and sepsis-induced neutropenia in preterm neonates at high risk of sepsis, and so removes an important risk factor for sepsis and sepsis-related mortality.GM-CSF, preterm neonates, neutropenia, sepsis.