Natural killer cell activity and delivery: possible influence of cortisol and anesthetic agents. A study on newborn cord blood

The aim of this study was to evaluate the influence of the method of delivery, the level of cord blood lidocaine, and the cortisol concentration on the cord blood natural killer (NK) activity in the full-term healthy newborn. We studied healthy newborns delivered by elective cesarean section without labor under general anesthesia (n = 24), delivered by cesarean section under epidural anesthesia (n = 21), and delivered vaginally with uncomplicated labor (n = 19). The NK cell activity was significantly lower in newborns delivered by cesarean section under epidural anesthesia than it was in the general anesthesia group, while it was similar to the levels found in vaginally delivered newborns. The cortisol concentration was highest in the vaginal delivery group (589.2 +/- 200 mmol/l) and lowest in the general anesthesia group (199.2 +/- 81.9 mmol/l). The mean serum lidocaine concentration was 414.1 +/- 370 microgram/l in the epidural anesthesia group and undetectable in the other groups. In conclusion, our data suggest that the cord blood NK activity was significantly influenced by the method of delivery. This effect could be related to anesthetics given to the mother for general or epidural anesthesia or to the endocrine-metabolic variations observed after different degrees of delivery-related stress. The NK cells being a first-line defense mechanism against viral infections, the results of this study suggest an association with the occurrence of early perinatal infections, especially in preterm infants.     

The Influence of Labor and Delivery on Preterm Fetal Adrenal Function

ABSTRACT. The influence of labor and route of delivery upon umbilical cord serum levels of Cortisol and dehydroepiandrosterone sulfate in one hundred sixty-nine preterm infants not exposed prena-tally to corticosteroids was studied. Vaginally born infants (group A, n=89) presented a higher mean cord Cortisol and dehydroepiandrosterone sulfate concentrations than those delivered by cesarean section (group B, n=80). Although there were no differences in Cortisol and dehydroepiandrosterone sulfate levels between infants delivered by cesarean section after spontaneous onset of labor (group B-I, n=42) and those without labor (group B-II, n=38), the mean Cortisol and dehydroepiandrosterone sulfate concentrations were higher in group A than in group B-I. There was a correlation between umbilical cord Cortisol and dehydroepiandrosterone sulfate levels. It is concluded that there is no association between the presence of labor and high cord serum levels of Cortisol and dehydroepiandrosterone sulfate and there is an association between vaginal delivery and high cord Cortisol and dehydroepiandrosterone sulfate levels in preterm infants. It is suggested that the stress of vaginal delivery stimulates the secretion of fetal Cortisol and dehydroepiandrosterone sulfate in preterm infants.     

The influence of labor and delivery on preterm fetal adrenal function

The influence of labor and route of delivery upon umbilical cord serum levels of cortisol and dehydroepiandrosterone sulfate in one hundred sixty-nine preterm infants not exposed prenatally to corticosteroids was studied. Vaginally born infants (group A, n = 89) presented a higher mean cord cortisol and dehydroepiandrosterone sulfate concentrations than those delivered by cesarean section (group B, n = 80). Although there were no differences in cortisol and dehydroepiandrosterone sulfate levels between infants delivered by cesarean section after spontaneous onset of labor (group B-I, n = 42) and those without labor (group B-II, n = 38), the mean cortisol and dehydroepiandrosterone sulfate concentrations were higher in group A than in group B-I. There was a correlation between umbilical cord cortisol and dehydroepiandrosterone sulfate levels. It is concluded that there is no association between the presence of labor and high cord serum levels of cortisol and dehydroepiandrosterone sulfate and there is an association between vaginal delivery and high cord cortisol and dehydroepiandrosterone sulfate levels in preterm infants. It is suggested that the stress of vaginal delivery stimulates the secretion of fetal cortisol and dehydroepiandrosterone sulfate in preterm infants.     

脐血采集方式对脐血造血细胞含量的影响

目的比较阴道分娩和剖宫产采集脐血所含造血细胞含量的差异,评估两种采集方式的优缺点。方法回顾性分析两种脐血采集方式间新生儿体重、采集体积、总有核细胞数(TNC)、CD34+细胞百分率、CD34+细胞数和总集落数(CFUs)的差异。结果采集体积在两组间差异无统计学意义(P>0.05)。而阴道分娩组TNC、CD34+细胞百分率、总CD34+细胞数、CFUs数明显高于剖宫产组,新生儿体重小于剖宫产组,差异有统计学意义(P<0.05)。新生儿体重在2.5kg～4.0kg时,阴道分娩组TNC、总CD34+细胞数和CFUs数明显高于剖宫产组,差异有统计学意义(P<0.05)。结论阴道分娩采集方式采集的脐血含有较高的造血细胞含量且有利于采集到更好脐血质量,可作为同胞脐血移植采集脐血的最优选分娩和采集方式。     

新生儿中性粒细胞CDllb表达的研究

目的 在分子水平上了解新生儿中性粒细胞的功能状态。方法 采用全血流式细胞术和直接免疫荧光法检测了33例正常足月新生儿中性粒细胞CD11b平均荧光强度（MFI）。10例健康成人作对照。结果 自然分娩脐血和成人静脉血中性粒细胞CD11b MFI均低于择期剖宫产脐血和新生儿静脉血（P均＜0．05），自然分娩脐血和成人静脉血间CD11b MFI差异无显著性（P＞0．05）。结论 分娩方式影响新生儿中性粒细胞CD11b表达。足月儿中性粒细胞静息状态下CD11b表达已基本成熟。     

Leukocyte counts in relation to the method of delivery during the first five days of life

The goal of the present study was to evaluate total and differential leukocyte counts during the first 5 days of life in relation to the method of delivery. We included 203 healthy term infants; of these, 114 were born by vaginal delivery, and 89 by elective cesarean section. Total and differential leukocyte counts were evaluated at the following intervals: 0-6, 7-12, 13-24, 25-48, 49-72, 73-96, and 97-120 h after birth. The cord serum cortisol level was measured as an indicator of the degree of delivery-related stress. Mean leukocyte and neutrophil counts were higher in infants born by vaginal delivery in cord blood and up to 12 h of life. No significant differences were observed in the immature: total neutrophil ratios between the two groups of infants. The cord serum cortisol level was higher in vaginally delivered infants. A significant correlation was found between cortisol and leukocyte, neutrophil, or lymphocyte counts. The method of delivery produces significantly different total leukocyte and neutrophil counts during the first 12 h after birth; after this time, there appears to be no more variation of leukocyte counts during the first 5 days of life.     

The effects of acute and chronic perinatal stress on plasma vasopressin concentration and renin activity at birth

The effects of acute and chronic intrauterine stress on plasma vasopressin (AVP) concentration and renin activity (PRA) in the cord blood of 36 newborn infants were studied. AVP concentrations in the umbilical artery were significantly higher than those in the umbilical vein in all infants, except in those delivered by elective cesarean section after normal pregnancy. AVP concentrations in the umbilical arterial blood after normal term pregnancy and vaginal delivery (779 pg/ml, log mean) were higher than those in the cord blood of infants delivered vaginally after maternal hypertensive disease (198 pg/ml). Compared to the values of the latter group, the AVP values were significantly lower (39 pg/ml) in infants delivered by cesarean section without labor because of severe growth retardation and decreased heart rate variability. The group of normal term infants delivered by elective cesarean section after normal pregnancy had the lowest AVP concentrations (13 pg/ml). PRA in the umbilical arterial blood was not different from that in the umbilical venous blood. The highest mean level of PRA (14.5 ng/ml/h) was observed in premature infants delivered by cesarean section because of fetal growth retardation and pathological heart rate variability, and the lowest mean level in term infants delivered by elective cesarean section (3.4 ng/ml/h). PRA was significantly increased in term infants delivered vaginally after normal pregnancy (7.8 ng/ml/h) or after hypertensive pregnancy (11.7 ng/ml/h) in comparison to that of term infants delivered by elective cesarean section.(ABSTRACT TRUNCATED AT 250 WORDS)     

In vivo effect of recombinant human granulocyte colony-stimulating factor on neutrophilic expression of CD11b in septic neonates: a randomized controlled trial

Neonates are susceptible to septicemia secondary to quantitative and qualitative neutrophilic defects. Granulocyte colony-stimulating factor (G-CSF) stimulates myeloid progenitor cell proliferation and induces selective neutrophil functions. The authors aimed to evaluate the effect of G-CSF administration in septic neonates on neutrophil production and CD11b expression. Sixty septic neonates were randomized to receive intravenous G-CSF 10 μg/kg/day for 3 days (G-CSF group, n = 30), or not to receive G-CSF (non-G-CSF group, n = 30). Thirty healthy newborns were included as controls. Laboratory investigations included complete blood count, C-reactive protein, blood culture, renal and liver function tests, and assessment of neutrophilic expression of CD11b. Total leukocytes count (TLC), absolute neutrophil count (ANC), and immature myeloid cell count in G-CSF group showed significant difference between post-and pre-G-CSF levels. TLC, ANC, immature myeloid cell count and immature/total myeloid cells ratio were higher in G-CSF group compared to non-G-CSF group on days 1 and 3. Higher neutrophilic expression of CD11b was reported in both septic groups on day 0 compared to control group. On day 5, CD11b was higher in G-CSF group than non-G-CSF group. G-CSF improved CD11b% in neutropenic and non-neutropenic septic neonates. No significant difference was found between pre- and posttreatment renal and liver function tests. Lower duration of antibiotic intake and hospitalization was observed in G-CSF group compared to non-G-CSF group. G-CSF administration as an adjuvant therapy for neonatal septicemia, whether neutropenic or not, improves neutrophilic count and function and contributed to early healing from sepsis.     

The effect of labor on neonatal T-cell phenotype and function

With increasing interest in the role of fetal programming in child and adulthood diseases, and therefore interest in the measurement of various factors at birth, it is essential to ascertain whether the factors of interest show any gestation- or parturition-associated changes. We have investigated whether mode of delivery influenced T-cell phenotype and function (CD4+) as has been described for monocytes and neutrophils. Interferon-gamma production in response to either the mitogen phytohemagglutinin or anti-CD2/CD3/CD28 F(ab')3 was significantly reduced by neonatal mononuclear cells compared with adult cells but did not differ with mode of delivery at term (normal vaginal delivery versus elective lower-segment cesarean section). Likewise, anti-CD2/CD3/CD28-stimulated IL-2 production by the neonate was lower than adult levels but did not differ with mode of delivery. The expression of common T-cell activation markers (CD25, MHC class II, CD69, CD62L, CD11a, CD44, and CD49d) was examined. Only CD62L (L-selectin) expression was significantly different, with fewer adult T cells expressing this surface antigen compared with neonatal T cells (p < 0.0003), and significantly more T cells from lower-segment cesarean section than normal vaginal delivery were positive for CD62L (p = 0.012). sCD62L levels were significantly lower in cord plasma compared with adult plasma but did not differ with mode of delivery. Thus the phenotype and function of cord blood T cells did not differ greatly with mode of delivery, but possible differences for the marker of interest should always be assessed. Furthermore, although there was no significant difference with mode of delivery for all markers, except CD62L, the variation in the normal vaginal delivery samples, as for the adults, was greater than in the lower-segment cesarean section samples, indicating that the effects of length of labor and stress at delivery may well be relevant.     

Labor promotes neonatal neutrophil survival and lipopolysaccharide responsiveness

Labor is a mild proinflammatory state that is associated with fetal leukocytosis. Elective cesarean section has been linked with increased neonatal morbidity, which may be partially immune mediated. We hypothesized that labor may alter neutrophil phenotype and thereby decrease neonatal complications. We characterized neutrophil function and survival in normal neonates after either uncomplicated vaginal delivery (VD) or elective cesarean section (CS) without labor. Spontaneous neutrophil apoptosis is delayed in cord blood neutrophils of neonates after normal labor (VD) compared with CS, as assessed by propidium iodide DNA incorporation using flow cytometry. This demonstrates their ability to maintain an inflammatory response. CD11b expression on neonatal neutrophils after CS is decreased, providing further evidence of altered activation or priming. Lipopolysaccharide responsiveness, characterized by CD11b and apoptosis, is similar in VD and adults, but CS-derived neutrophils are unresponsive. Baseline TLR-4 levels are elevated in CS in contrast to the other groups, although expression is not up-regulated by lipopolysaccharide co-incubation. Neonatal neutrophil survival and function are altered by labor and may increase antibacterial function and neutrophilia. This suggests that labor of any duration may be immunologically beneficial to the normal term neonate.     

影响脐血造血干细胞移植供体品质的相关因素分析

目的探讨影响脐血产品质量的供体相关因素,建立选择脐血移植供体的最优化标准。方法脐血采集自2000年6月至2006年12月在广州市妇婴医院足月分娩的产妇,分析脐血的总有核细胞数(TNC)、CD+34细胞数和总集落数(CFUs)与脐血供体相关因素(新生儿性别和体重、产妇年龄、孕周、分娩方式、胎粪污染、采集体积)的关系。结果TNC与CD+34细胞数、总集落数三者两两间均有相关性,TNC与CD3+4细胞数相关性最好。TNC与新生儿体重、采集体积、产妇年龄有相关关系;阴道分娩、孕周(40周和女性新生儿组TNC数分别高于剖宫产、36~40孕周和男性组。CD+34细胞数和总集落数与采集体积有相关关系,与新生儿体重、产妇年龄无相关关系。CD3+4细胞数受分娩方式的影响(阴道分娩高于剖宫产),不同新生儿性别及孕周间差异无统计学意义。阴道分娩和男性组总集落数分别高于剖宫产和女性组,两组孕周间总集落数差异无统计学意义。采集体积与新生儿体重有关,与产妇年龄、分娩方式、新生儿性别、孕周无关。胎粪污染时TNC较高,CD+34细胞数、总集落数均无影响。结论孕周和新生儿体重指标增加到标准化的脐血采集前供体选择标准,将有利于获得更好的脐血采集质量、提高库存脐血的有效性。     

Neonatal B lymphocyte subpopulations and method of delivery.

We studied four groups of healthy term newborn infants: (1) 11 infants born by vaginal delivery; (2) 11 infants born by elective cesarean section; (3) 10 infants born by emergency cesarean section with labor, and (4) 10 infants born by complicated vaginal delivery. Total and differential leukocyte counts, cortisol blood level, and B lymphocyte subpopulations (SmIg, sIgD, sIgM, CD19, CD20, CD21, CD23) were evaluated in cord blood samples from the four infant groups. Furthermore, the Pentothal blood level was measured in infants born by elective cesarean section and in their mothers at delivery. Higher total and differential leukocyte counts and cortisol blood levels were observed in group 1 and 4 infants as compared with group 2 and 3 infants. A significant correlation was observed between cortisol blood level and leukocyte counts. The percentages of positivity to cell surface markers of B lymphocyte subpopulations were significantly higher in infants born by elective cesarean section. A negative significant correlation of thiopentone with sIgM and CD21 was observed. These data indicate a significant influence of method of delivery and of thiopentone on B lymphocyte subpopulations.     

The stress of birth enhances in vitro spontaneous and IL-8-induced neutrophil chemotaxis in the human newborn

The birth process induces fetal stress. Stress has profound effects on the immune system, also by acting on the trafficking of leukocytes, a process in which adhesion and chemotaxis are primordial and critical events for the development of effective antimicrobial defenses. The newborn is rapidly challenged by a microflora at the epithelia linings and therefore depending on early, innate immunity onset. The objective of the study was to investigate the immune response in cord blood from newborns in relation to different degrees of fetal stress, with focus on neutrophil chemotaxis. We analyzed in vitro transmigration ability of neutrophils and their CD11b expression, measured total white blood count (WBC) and the major leukocyte populations, interleukin (IL)-8, interferon (IFN)-gamma, and soluble E-Selectin, as well as relevant immuno-modulating hormones in infants born at term after Cesarean section prior to the start of labor (n = 55), normal vaginal delivery (n = 87), and assisted delivery (n = 26). Arterial pH and lactate were used as stress markers. We found that spontaneous and IL-8-induced transmigration ability of neutrophils from newborns after normal delivery was significantly higher compared with that of neutrophils from Cesarean section or from adults. With a progressive increase in fetal stress, there were significant elevations in total WBC, in particular neutrophils and monocytes, as well as an enhanced IL-8 and soluble E-Selectin level. Assisted delivery, associated with the highest degree of fetal stress in addition had an enhanced lymphocyte and monocytes count as well as an increased IFN-gamma level. There were significant direct correlations between neutrophils and monocytes, respectively, with cortisol, beta-endorphin, and prolactin. Interferon-gamma was directly related to dopamine, as well as to the lymphocyte and monocyte count. The setting of the HPA-axis at birth is a promoter of an alarm response and a surge of neuroendocrine immuno-modulating factors that enhances antimicrobial defenses of the newborn. We speculate that IL-8 induced by normal labor may be a priming factor for an increased neutrophil chemotaxis through the pre-activated endothelium of the fetus. Assisted delivery may trigger excessive recruitment of additional inflammatory cells and IFN-gamma release.     

In Vivo Effect of Recombinant Human Granulocyte Colony-Stimulating Factor on Neutrophilic Expression of CD11b in Septic Neonates: A Randomized Controlled Trial

Neonates are susceptible to septicemia secondary to quantitative and qualitative neutrophilic defects. Granulocyte colony-stimulating factor (G-CSF) stimulates myeloid progenitor cell proliferation and induces selective neutrophil functions. The authors aimed to evaluate the effect of G-CSF administration in septic neonates on neutrophil production and CD11b expression. Sixty septic neonates were randomized to receive intravenous G-CSF 10 μg/kg/day for 3 days (G-CSF group, n = 30), or not to receive G-CSF (non–G-CSF group, n = 30). Thirty healthy newborns were included as controls. Laboratory investigations included complete blood count, C-reactive protein, blood culture, renal and liver function tests, and assessment of neutrophilic expression of CD11b. Total leukocytes count (TLC), absolute neutrophil count (ANC), and immature myeloid cell count in G-CSF group showed significant difference between post–and pre–G-CSF levels. TLC, ANC, immature myeloid cell count and immature/total myeloid cells ratio were higher in G-CSF group compared to non–G-CSF group on days 1 and 3. Higher neutrophilic expression of CD11b was reported in both septic groups on day 0 compared to control group. On day 5, CD11b was higher in G-CSF group than non–G-CSF group. G-CSF improved CD11b% in neutropenic and non-neutropenic septic neonates. No significant difference was found between pre- and posttreatment renal and liver function tests. Lower duration of antibiotic intake and hospitalization was observed in G-CSF group compared to non–G-CSF group. G-CSF administration as an adjuvant therapy for neonatal septicemia, whether neutropenic or not, improves neutrophilic count and function and contributed to early healing from sepsis.     

Umbilical cord cortisol and prolactin levels in preterm infants. Relation to labor and delivery

The influence of labor and route of delivery upon the umbilical cord serum levels of cortisol and prolactin in ninety-nine preterm infants not exposed prenatally to corticosteroids was studied. Vaginally born infants (group A) presented a higher mean cord cortisol concentration than those delivered by cesarean section (group B); mean prolactin values, however, were not different between both groups. Although there was no difference in cortisol and prolactin levels between infants delivered by cesarean section after spontaneous onset of labor (group B-I) and those without labor (group B-II), the mean cortisol concentration was significantly higher in group A than in group B-I. The mean prolactin levels did not differ among all the studied groups. It is concluded that there is no association between presence of labor or route of delivery and cord serum levels of prolactin, there is no association between spontaneous preterm labor and cord cortisol values and there is an association between vaginal delivery and high cord cortisol levels in preterm infants. It is suggested that the increase in serum cortisol levels does not precede the initiation of preterm parturition but it is secondary to the stress caused by vaginal delivery.     

Maternal pulse oximetry perfusion index as a predictor of early adverse respiratory neonatal outcome after elective cesarean delivery.

OBJECTIVE: Evidence suggests increased morbidity, in particular early neonatal respiratory complications, in newborns from elective cesarean section compared with those from vaginal delivery. No reliable maternal predictors of adverse neonatal outcome at elective cesarean section are known. Here, we prospectively tested the hypothesis that a low maternal perfusion index at the baseline phase (i.e., preanesthesia) of the elective cesarean section is a predictor of early adverse neonatal respiratory outcome. DESIGN: Prospective cohort study. SETTING: Operating and delivery rooms of a public health hospital with a tertiary-level neonatal intensive care unit. PATIENTS: Forty-four healthy pregnant women with no known risk factors undergoing elective cesarean section at term gestation. INTERVENTIONS: Elective cesarean section was divided into nine phases. Analysis of pulse oximetry-derived signals (perfusion index, pulse rate, and oximetry) and systolic, diastolic, and differential blood pressure were recorded. Maternal arterial and venous newborn cord blood gas analyses and placental histology were evaluated. MEASUREMENTS AND MAIN RESULTS: Early respiratory complications (transient tachypnea of the newborn, n = 5; respiratory distress syndrome, n = 1) were observed in 13.6% (6 of 44) of the newborns. A maternal perfusion index < or = 1.9 (lower quartile) during the preanesthesia phase of the elective cesarean section was an independent predictor of early adverse neonatal respiratory outcome (odds ratio 68.0, 95% confidence interval 6.02-767.72; p < .0001). CONCLUSIONS: A decreased perfusion index value in the preanesthesia phase of elective cesarean section is a maternal predictor of increased neonatal morbidity and is significantly related to subclinical placental inflammatory disease. These observations suggest the feasibility of a noninvasive pulse oximeter prenatal screening of the high-risk fetus/newborn in elective cesarean section.     

Granulocyte functions and changes in ability with age in newborns; Report no. 2: Activation of granulocyte functions by cytokines

BACKGROUND: The aim of the present study was to examine the function of granulocytes in newborns from the perspective of granulocyte activation by cytokines. METHODS: Granulocytes were stimulated with tumor necrosis factor-alpha, granulocyte-macrophage colony stimulating factor (GM-CSF) or granulocyte colony stimulating factor, and the reactivity of granulocytes to these substances was then compared between newborns (umbilical cord blood, peripheral blood obtained at age 5 days and at age 1 month) and peripheral blood obtained from adults. In addition, the expression of cytokine receptors on the surface of granulocytes was measured for each age group. RESULTS: The amplification of CD11b expression on the surface of granulocytes and suppression of l-selectin expression were weaker for cord blood regardless of which cytokine was added. In addition, the increases in the activity of intracellular elastase when stimulated with tumor necrosis factor-alpha or GM-CSF were significantly lower for cord blood. Moreover, the expression of GM-CSF receptors and granulocyte colony stimulating factor receptors on the surface of granulocytes was lower for cord blood, and this expression approached the level found in adults as age increased. CONCLUSION: Granulocytes during early infancy exhibit low reactivity to inflammatory cytokines, and this was considered to be one of the factors contributing to the higher incidence of serious bacterial infections in infants.     

Birth by cesarean section is associated with elevated neonatal plasma levels of dimethylarginines

Background: This study was undertaken to compare the effects of vaginal delivery and cesarean section on the l‐arginine‐nitric oxide system by measuring levels of l‐arginine, an endogenous nitric oxide synthase antagonist asymmetric dimethylarginine (ADMA), and symmetric dimethylarginine (SDMA) in the cord blood and postnatally. Methods: Plasma samples were obtained from the umbilical vein and artery at birth and from peripheral venous blood on the second postnatal day in 30 full‐term newborn infants: 10 born vaginally and 20 born by cesarean section. Results: After vaginal delivery, ADMA concentration was higher in the umbilical vein than in the umbilical artery (mean 1.06 vs 0.90 µmol/L [P= 0.027]); and ADMA level fell after birth to 0.66 µmol/L on the second postnatal day (P= 0.007 vs umbilical artery). Newborns born by cesarean section had similar ADMA levels in umbilical arterial and venous blood, 1.19 and 1.18 µmol/L, and the ADMA level fell to 0.84 µmol/L by the second postnatal day (P < 0.001). Vaginal birth induced neither significant umbilical venoarterial difference nor a postnatal fall in SDMA. After cesarean section, SDMA was essentially the same in umbilical vein, umbilical artery and postnatal peripheral vein samples. At 2 days of age, both ADMA and SDMA levels stayed higher in infants born by cesarean section than in vaginally born infants. Conclusions: ADMA level falls after both vaginal and cesarean birth, whereas SDMA level does not. The higher ADMA level after cesarean birth compared with vaginal birth may contribute to decreased nitric oxide production and bioavailability in neonatal vascular beds.     

正常足月儿脐血粒细胞集落刺激因子水平与白细胞的相关性

目的 研究正常足月儿脐血粒细胞集落刺激因子（G-CSF）水平与白细胞数、中性粒细胞数及分化抗原CD13、CD33表达的相关性。方法 采用ELISA法测定了33例正常足月儿脐血G-CSF水平，并用Counter Electronics仪计数了同一标本脐血白细胞和中性粒细胞数，用免疫荧光法计数了同一标本脐血CD13、CD33阳性细胞数。结果 21例脐血G-CSF检测阳性标本，经统计学处理后发现G-CSF水平与其他4项均无明显相关性。结论 G-CSF与白细胞增殖分化之间并不是简单而唯一的调节关系，可能有其他细胞因子参与调节。