Il-1 beta, Il-6, Il-8 and G-CSF in the diagnosis of early-onset neonatal infections

Prolonged premature rupture of membranes with increased risk of infection is associated with gut accumulation of Pseudomonas from the environment

Background

Preterm premature rupture of membranes (PPROM) contributes to over one-third of preterm births, and PPROM infants are more susceptible to infections. However, the risk factors remain poorly understood. We here aim to investigate the association of duration of premature rupture of membranes (PROM) and environmental microbiota with the gut microbiota and infection in PPROM infants.

Methods

Forty-six premature infants were recruited from two hospitals, and infant fecal and environmental samples were collected. 16 s rRNA sequencing was performed to analyze the fecal and environmental microbiome. Human inflammatory cytokines in cord vein plasma were measured.

Results

The gut microbiota composition of PPROM infants was different from that of non-PPROM infants, and the microbiome phenotypes were predicted to be associated with a higher risk of infection, further evidenced by the significantly increased levels of IL-6 and IL-8 in cord vein plasma of PPROM infants. The diversity of the gut microbiota in PPROM infants increased significantly as the duration of PROM excessed 12 h, and Pseudomonas contributed significantly to the dynamic changes. The Pseudomonas species in the gut of PPROM infants were highly homologous to those detected in the ward environment, suggesting that prolonged PROM is associated with horizontal transmission of environmental pathogens, leading to a higher risk of infection.

Conclusions

This study highlights that the duration of PROM is associated with the accumulation of environmental pathogens in the gut of PPROM infants, which is a risk factor for nosocomial infections. Improving environmental hygiene could be effective in optimizing the clinical care of PPROM infants.

The Role of the Interleukin-1 Family in Complications of Prematurity

Preterm birth is a major contributor to neonatal morbidity and mortality. Complications of prematurity such as bronchopulmonary dysplasia (BPD, affecting the lung), pulmonary hypertension associated with BPD (BPD-PH, heart), white matter injury (WMI, brain), retinopathy of prematurity (ROP, eyes), necrotizing enterocolitis (NEC, gut) and sepsis are among the major causes of long-term morbidity in infants born prematurely. Though the origins are multifactorial, inflammation and in particular the imbalance of pro- and anti-inflammatory mediators is now recognized as a key driver of the pathophysiology underlying these illnesses. Here, we review the involvement of the interleukin (IL)-1 family in perinatal inflammation and its clinical implications, with a focus on the potential of these cytokines as therapeutic targets for the development of safe and effective treatments for early life inflammatory diseases.

Dual inhibition of complement C5 and CD14 attenuates inflammation in a cord blood model

BACKGROUND

Escherichia coli and Group B streptococci (GBS) are the main causes of neonatal early-onset sepsis (EOS). Despite antibiotic therapy, EOS is associated with high morbidity and mortality. Dual inhibition of complement C5 and the Toll-like receptor co-factor CD14 has in animal studies been a promising novel therapy for sepsis.

METHODS

Whole blood was collected from the umbilical cord after caesarean section (n = 30). Blood was anti-coagulated with lepirudin. C5 inhibitor (eculizumab) and anti-CD14 was added 8 min prior to, or 15 and 30 min after adding E. coli or GBS. Total bacterial incubation time was 120 min (n = 16) and 240 min (n = 14). Cytokines and the terminal complement complex (TCC) were measured using multiplex technology and ELISA.

RESULTS

Dual inhibition significantly attenuated TCC formation by 25-79% when adding inhibitors with up to 30 min delay in both E. coli- and GBS-induced inflammation. TNF, IL-6 and IL-8 plasma concentration were significantly reduced by 28-87% in E. coli-induced inflammation when adding inhibitors with up to 30 min delay. The dual inhibition did not significantly reduce TNF, IL-6 and IL-8 plasma concentration in GBS-induced inflammation.

CONCLUSION

Dual inhibition of C5 and CD14 holds promise as a potential future treatment for severe neonatal EOS.

IMPACT

Neonatal sepsis can cause severe host inflammation with high morbidity and mortality, but there are still no effective adjunctive immunologic interventions available. Adding CD14 and complement C5 inhibitors up to 30 min after incubation of E. coli or Group B streptococci in a human umbilical cord blood model significantly reduced complement activation and cytokine release. Dual inhibition of C5 and CD14 is a potential future therapy to modulate systemic inflammation in severe cases of neonatal sepsis.

The role of interleukin-1 in perinatal inflammation and its impact on transitional circulation

Preterm birth is defined as delivery at <37 weeks of gestational age (GA) and exposes 15 million infants worldwide to serious early life diseases. Lowering the age of viability to 22 weeks GA entailed provision of intensive care to a greater number of extremely premature infants. Moreover, improved survival, especially at extremes of prematurity, comes with a rising incidence of early life diseases with short- and long-term sequelae. The transition from fetal to neonatal circulation is a substantial and complex physiologic adaptation, which normally happens rapidly and in an orderly sequence. Maternal chorioamnionitis or fetal growth restriction (FGR) are two common causes of preterm birth that are associated with impaired circulatory transition. Among many cytokines contributing to the pathogenesis of chorioamnionitis-related perinatal inflammatory diseases, the potent pro-inflammatory interleukin (IL)-1 has been shown to play a central role. The effects of utero-placental insufficiency-related FGR and in-utero hypoxia may also be mediated, in part, via the inflammatory cascade. In preclinical studies, blocking such inflammation, early and effectively, holds great promise for improving the transition of circulation. In this mini-review, we outline the mechanistic pathways leading to abnormalities in transitional circulation in chorioamnionitis and FGR. In addition, we explore the therapeutic potential of targeting IL-1 and its influence on perinatal transition in the context of chorioamnionitis and FGR.

Postnatal changes of cytokines in premature infants with or without funisitis

OBJECTIVE

Fetal inflammatory response syndrome (FIRS), which induces hypercytokinemia, is important for the outcomes of premature infants. It is necessary to focus on the fetal inflammatory environments.

METHODS

A total of 37 premature infants (gestational age ≤32 weeks) were divided into three groups: (1) 15 without chorioamnionitis (CAM) and funisitis; C(-)F(-) group, (2) 15 with CAM but without funisitis; C(+)F(-) group and (3) 7 with CAM and funisitis; C(+)F(+) group. Blood interleukin (IL)-1β, IL-6 and IL-8 levels were measured on day 0 (= in umbilical cord blood), 3, 7, 14, 21 and 28.

RESULTS

(1) day 0: Cord blood concentrations of IL-1β, IL-6 and IL-8 were significantly higher in the C(+)F(+) group than in the C(+)F(-) group and C(-)F(-) group. On the other hand, they were comparable between the C(+)F(-) group and C(-)F(-) group. (2) Days 3-28: elevated cytokines levels in the C(+)F(+) group with funisitis decreased on day 3 and later.

CONCLUSIONS

We suggested that hypercytokinemia in the cord blood in premature infants were greatly related with funisitis. Diagnosis of funisitis would be important to find the premature infants who need to be managed their risk of FIRS. In addition, hypercytokinemia disappeared in a few days after birth; therefore, cord blood data analysis of cytokines and/or inflammation-related proteins concentrations is necessary to evaluate the fetal inflammatory environments in premature infants after birth.

Laboratory aid to the diagnosis and therapy of infection in the neonate

Despite the advances in perinatal and neonatal care and use of newer potent antibiotics, the incidence of neonatal sepsis remains high and the outcome is still severe. For years, investigators have sought a test or panel of tests able to identify septic neonates accurately and rapidly in order to obtain an early diagnosis and develop a specific effective treatment for a successful outcome. In addition to the standard procedures (blood, CSF, and urine cultures), such panels have included a combination of haematological investigations (total, differential and immature cell counts), and levels of acute-phase reactants (principally CRP and procalcitonin), and cytokines (such as IL-6 or neutrophil CD64). Furthermore, the science of proteomics and genomics has been applied to the search for bio-markers, production of protein profiles and genetic polymorphisms that can rapidly help the prediction, early diagnosis, and treatment of human diseases, but, for now, data are as yet insufficient to confirm their validity.

Integrated review of cytokines in maternal, cord, and newborn blood: part II-- associations with early infection and increased risk of neurologic damage in preterm infants

A growing body of literature supports the relationship of maternal inflammation with preterm birth and adverse neonatal outcomes, including infection and central nervous system (CNS) dysfunction. Mediators of inflammation, most notably proinflammatory cytokines, have been implicated as having an association with and perhaps playing a causal role in the pathogenesis, leading to adverse neonatal outcomes. Even though the association of cytokines with early adverse neonatal outcomes has been actively pursued as a line of research, there has been little integration of diverse findings across studies. Therefore, the purpose of this systematic review was to appraise and classify empirical evidence from human studies for the association of cytokine levels in blood (serum, plasma, or cells; maternal, cord, or neonatal) with two adverse early outcomes in preterm infants: early infection and increased risk of neurologic damage. The review revealed that the proinflammatory cytokines most frequently linked with sepsis are in the interleukin (IL) 1 family as well as tumor necrosis factor alpha (TNF-alpha) and IL-6. The proinflammatory cytokines most frequently linked to neurologic insult in the reviewed studies were IL-1beta, IL-6, and IL-8. In all cases where IL-1beta was studied, the levels were increased when there was neurologic insult. A better understanding of the relationship of these inflammatory substances with these adverse conditions is needed for the future development of maternal and neonatal biobehavioral nursing research.

Comparison of markers for fetal inflammatory response syndrome: fetal blood interleukin-6 and neonatal urinary beta(2)-microglobulin

AIM

Chronic lung disease (CLD) is a major component in the morbidity of premature infants suffering from fetal inflammatory response (FIRS). The aim of the present study was to compare the value of measuring neonatal urinary beta(2)-microglobulin (beta(2)-MG) levels with fetal blood interleukin (IL)-6 levels in premature infants at risk of developing CLD.

METHODS

Premature infants (gestational age <30 weeks) without CLD (n = 19) and with CLD (n = 10) were enrolled. We measured IL-6 levels in umbilical cord blood and beta(2)-MG levels in urine obtained within 48 h after birth.

RESULTS

IL-6 and beta(2)-MG levels were significantly higher in infants who developed CLD than in those who did not (median IL-6, 54.7 vs 7.6 pg/mL; P < 0.005; beta(2)-MG 17.7 vs 9.3 x 10(4) microg/gCr; P < 0.05). The sensitivity and negative predictive value of beta(2)-MG at the cut-off value at 10.0 x 10(4) microg/gCr (0.90 and 0.92) were comparable to IL-6 at 16 pg/mL (0.90 and 0.94).

CONCLUSION

We suggest that measuring urinary beta(2)-MG in premature infants soon after birth can monitor FIRS and may provide information on the risk of subsequent CLD development that is as clinically important as information derived from umbilical cord blood IL-6.

Below median birth weight in appropriate-for-gestational-age preterm infants as a risk factor for bronchopulmonary dysplasia

AIMS

To assess the presence of chorioamnionitis and intrauterine growth as prenatal risk factors for broncho pulmonary dysplasia (BPD) in appropriate-for-gestational-age (AGA) infants of <28 weeks' gestation.

METHODS

Gender, race, birth weight, gestational age, histology of the placenta, diagnosis of BPD at 36 weeks' gestation, postnatal dexamethasone treatment, and death were recorded in 150 preterm infants born at <28 weeks' gestation, and admitted between 1996 and 2001.

RESULTS

In 122 AGA infants (mean gestational age: 26.18 weeks, mean birth weight: 837 g), BPD was associated with gestational age-related birth weights below the 50(th) centile. Intrauterine growth deceleration started between 25 and 26 weeks' gestation. Chorioamnionitis was not related to BPD.

CONCLUSIONS

AGA infants of 26-28 weeks' gestation with birth weights below the median showed an increased risk of developing BPD.

The antenatal identification of funisitis with a rapid MMP-8 bedside test

AIMS

The purpose of this study was to determine if a bedside test, the MMP-8 PTD Check, can be of value in the antenatal identification of funisitis. This test can be performed in 15 min without any laboratory equipment.

METHODS

The relationship between the presence or absence of funisitis and the results of an MMP-8 PTD Check was examined in 139 patients who delivered preterm singleton neonates (gestational age <35 weeks) within 72 h of amniocentesis. Amniotic fluid (AF) was cultured for aerobic and anaerobic bacteria and for genital mycoplasmas. AF was analyzed for white blood cell (WBC) count, interleukin-6 (IL-6) and an MMP-8 PTD Check. The IL-6 concentration was also determined in umbilical cord plasma collected at birth. Funisitis was diagnosed in the presence of neutrophil infiltration into the umbilical vessel walls or Wharton's jelly.

RESULTS

1) Funisitis was present in 27% (38/139) of cases; 2) A positive MMP-8 PTD Check had a sensitivity of 97% (37/38), a specificity of 63% (64/101), a positive predictive value of 50% (37/74) and a negative predictive value of 99% (64/65) in the identification of funisitis; 3) Among cases without funisitis, patients with a positive MMP-8 PTD Check had a significantly higher median AF IL-6 concentration, AF WBC count, and umbilical cord plasma IL-6 concentration at birth than those with a negative MMP-8 PTD Check (P<0.05 for each).

CONCLUSIONS

The MMP-8 PTD Check is a rapid, simple and sensitive bedside test which allows assessment of the risk of funisitis.

Levels of pro-inflammatory cytokines produced from cord blood in-vitro are pathogen dependent and increased in comparison to adult controls

BACKGROUND

Overproduction of pro-inflammatory cytokines may play a role in increased morbidity and mortality from neonatal sepsis. Objective of this study was to compare secretion of pro-inflammatory cytokines by the cord blood cells of healthy term neonates to the venous blood cells of healthy adults in vitro after stimulation with common neonatal pathogens.

METHOD

Blood samples were cultured in the presence of heat-killed group B beta-hemolytic streptococci (GBS), Escherichia coli (E. coli) and Staphylococcus epidermidis (S. epi). Concentrations of secreted cytokines (interleukine-6, IL-6, tumor necrosis factor-alpha, TNF-alpha, interleukine-1 beta, IL-1beta and interleukine-8, IL-8) were measured after 0, 1, 2 and 4 h of incubation using chemiluminescent immunometric automated assay.

RESULTS

Blood samples from 22 neonates and 16 adults were compared. After stimulation by GBS and E. coli, cord blood cells secreted significantly higher levels of IL-6 and IL-8 than blood cells of healthy adults. In cord blood, E. coli induced secretion of higher concentration of IL-6, TNF-alpha, IL-1beta and IL-8 than S. epi, and more IL-6 than GBS; GBS induced more IL-1beta than S.epi.

CONCLUSIONS

Response of cord blood to microbial activators is different from that of adult controls. Each isolate of heat-killed bacteria induced different amount of pro-inflammatory cytokines in vitro. This may represent a useful in vitro virulence test.

Maternal plasma interleukin-6, interleukin-1beta and C-reactive protein as indicators of tocolysis failure and neonatal outcome after preterm delivery

OBJECTIVE

To investigate whether maternal serum interleukin-6 (IL-6), interleukin-1beta (IL-1beta) and high sensitive C-reactive protein (CRP) could be used as markers of tocolysis failure and adverse neonatal outcome in pregnancies with preterm labor (PL).

METHODS

Forty-seven maternal blood samples taken because of PL at admission and delivery were analyzed. Control samples were taken from 20 gravidas with normal pregnancies. Differences in interleukins and CRP levels with or without chorioamnionitis, connatal infection or periventricular leukomalacia (PVL) were analyzed. Cut-off values were estimated for prediction of tocolysis failure and adverse neonatal outcome.

RESULTS

All three parameters were significantly higher in patients delivering prematurely than in patients delivering at term. All three parameters were significantly higher with than without histologic chorioamnionitis (p < 0.001), with than without connatal infection (p < 0.01), with than without PVL (p < 0.01 for IL-6 and IL-1beta, p < 0.05 for CRP), and in pregnancies with preterm premature rupture of membranes (PPROM) delivered within 48 hours compared to those more prolonged (p < 0.01). Choosing 50.9 pg/mL of IL-6 and a CRP of 19.7 as cut-offs in maternal blood admission concentrations for neonatal PVL, resulted in sensitivity of 81% and specificity of 91% and sensitivity of 91% and specificity of 81%, respectively. At respective maternal blood admission cut-off levels of 27.8 pg/mL of IL-6 and 8.9 of CRP, both parameters were effective predictors of connatal infection.

CONCLUSIONS

Maternal blood IL-6 and CRP could become useful in predicting tocolysis failure and intrauterine treat for the fetus.

Rapid simultaneous measurement of multiple cytokines using 100 microl sample volumes--association with neonatal sepsis

Early diagnosis of neonatal infection has proved problematic due to the inadequacy of currently available laboratory tests. Neonatal sepsis is associated with an increase in plasma-derived cytokine levels, but an increase of a single cytokine cannot identify neonatal sepsis specifically and multiple cytokine levels are required. The time constraints and relatively large volume of plasma required to measure multiple cytokines from newborn infants by conventional enzyme-linked immunosorbent assay (ELISA) techniques is prohibitive. We therefore applied cytometric bead array (CBA) technology for simultaneous measurement of multiple cytokines from a group of 18 term neonates with infection confirmed by culture and a control group. 'Normal' ranges were established for each cytokine from 1-7-, 8-14- and 15-21-day-old newborns. There was no significant change in the levels of cytokines from infants in different control age groups, suggesting that basal cytokine levels are unchanged in the first 3 weeks of life. In the patient groups, however, there was a significant difference in several cytokines between the different age groups. Interleukin (IL)-6, IL-10 and IL-12 were increased significantly in the 1-7-day-old patient group compared to either the 8-14 and 15-21 age group, suggesting that infection in utero is associated with increased levels of these cytokines compared to infection acquired following birth. When individual patient cytokine levels were compared to normal control reference ranges, two patients failed to show significant elevation of any cytokine tested. All other patients showed elevated levels of between one and nine cytokines tested (mean of 4.6). There was no correlation between elevated cytokine levels and types of infective organism or patient age. In conclusion, neonatal sepsis is associated with the elevation of multiple plasma cytokines. The use of CBA kits is a rapid, easy, low sample volume and sensitive method to measure multiple plasma cytokines.

Relationship between histologic chorioamnionitis and early inflammatory variables in blood, tracheal aspirates, and endotracheal colonization in preterm infants

Histologic results of the placenta are usually not available within the first days of life. We identified inflammatory variables in tracheal aspirates and blood that were associated with histologic chorioamnionitis (HC). A derivation cohort consisted of 62 neonates and a validation cohort of 57 neonates with a gestational age < 31 wk and ventilated on d 1. Tracheal aspirates were taken on d 1 and on d 3, if the patient was still ventilated. HC was diagnosed by light microscopy. Logistic regression was used to identify independent factors in the derivation cohort associated with HC at d 1, 2, and 3. Model performance was studied using receiver operating characteristic curve analysis. Independent factors associated with HC were, at d 1, tracheal aspirate IL-8 >or= 917 pg/mL (odds ratio, 60.7; 95% confidence interval, 11-328); at d 2, blood C-reactive protein >or= 14 mg/L (odds ratio, 9.2; 95% confidence interval, 2-38), blood white blood cell count >or= 10400/mm3 (odds ratio, 7.4; 95% confidence interval, 2-28); and at d 3, blood neutrophil count >or= 4968/mm3 (odds ratio, 14; 95% confidence interval, 3-57). The association with HC was less at d 3 (area under receiver operating characteristic curve, 0.77) when compared with the d 1 model (area under the curve, 0.88; p = 0.09). The models performed equally well in the validation cohort (goodness-of-fit test, p > 0.05). We conclude that the d 1 and d 2 models can be used as diagnostic factors for HC. Tracheal aspirate IL-8 taken immediately after birth was equally accurate in the diagnosis of HC as systemic inflammatory response at d 2 and better than on d 3.

Urinary beta 2-microglobulin in premature infants with chorioamnionitis and chronic lung disease

The urinary beta(2)-microglobulin (MG) concentration on day 0 to 2 was significantly higher in premature infants with chorioamnionitis (CAM) than in infants without CAM and in infants who developed chronic lung disease (CLD) than in those who did not. We propose that an elevated urinary beta(2)-MG can indicate a fetal inflammatory response and identify neonates at risk for the development of CLD.

Evaluation of laboratory markers for the detection of infections in open-heart surgery patients

This study compared the efficiency of interleukin-6 (IL-6), human neutrophil lipocalin (HNL), C-reactive protein (CRP) and white blood cell (WBC) count for the early detection of postoperative bacterial infections after open-heart surgery. These laboratory markers were determined preoperatively and monitored daily during the first 6 postoperative days. Postoperative bacterial infections were diagnosed in 17 of 54 studied patients needing at least 3 d of intensive care. Patients with less than 3 d of intensive care were not studied. HNL and WBC count showed no significant differences between infected and non-infected groups, whereas both IL-6 and CRP were significantly higher in the infected group. IL-6 levels were higher (p < 0.01) in the infected patients on the first postsurgical day, although with considerable interindividual variation. CRP levels rose on the second postsurgical day and showed less variation (p < 0.01). Calculation of the differences between preoperative and postoperative levels of IL-6 and CRP was not helpful for early detection of postoperative infections. Although IL-6 showed an earlier mean rise than CRP in patients developing postoperative infection, its substantial interindividual variation limits its clinical usefulness. HNL and WBC counts were ineffectual as indicators of postoperative infections in this study.

Expression and regulation of B7 family molecules on macrophages (MPhi) in preterm and term neonatal cord blood and peripheral blood of adults

BACKGROUND

Macrophage (MPhi) receptors of the B7 family (CD80, CD86) play a crucial role in T cell activation: the lack of costimulation leads to anergy or apoptosis of reactive T cells. MPhi may differentiate into different subsets, the balance of which defines MPhi-dependent T cell reactions. The aim of this study was to examine neonatal and adult T cell response with respect to the costimulatory MPhi-potential in order to identify molecular predictors for the neonatal immune defense.

METHODS

MPhi from peripheral blood (PBMPhi) or cord blood (CBMPhi) were stimulated with interferon-gamma (IFN-gamma), cyclic adenosine monophosphate (cAMP), CD40 ligand (CD40L), or alphaCD3.

RESULTS

As compared to PBMPhi, CBMPhi showed a significantly decreased upregulation of CD80 and/or CD86 after stimulation with IFN-gamma, cAMP, CD40L, and alphaCD3. Accordingly, the proliferative T cell response was impaired in the presence of CBMPhi. The fraction of T cells that underwent cell death was higher, and blast formation was significantly lower than that observed in the presence of PBMPhi.

CONCLUSIONS

CBMPhi, as compared to PBMPhi, delivered fewer costimulatory but more cytotoxic signals to T cells. These observations suggest that MPhi are one factor explaining the suboptimal immune defense of neonates and their increased susceptibility to infection. Using the costimulatory MPhi-potential as a predictor for immune responses requires a separate reference value system in neonatology.

Inflammatory mediators in perinatal asphyxia and infection

AIM

To determine serum levels of interleukin-6 (IL-6), IL-1beta, tumor necrosis factor-alpha (TNF-alpha), soluble intercellular adhesion molecule-1 (sICAM-1) and C-reactive protein (CRP) in asphyxiated neonates and compare these inflammatory factors with those found in neonates with perinatal infection.

METHODS

88 neonates were studied, of whom 36 were asphyxiated, 18 were infected and the remaining 34 were controls. Peripheral blood samples were obtained on the 1st, 3rd and 5th postnatal days.

RESULTS

Cytokines IL-6 and IL-1beta as well as sICAM-1 serum levels did not differ between asphyxiated and infected neonates; however, at most time periods, their values were significantly higher than controls. TNF-alpha was similar in the three groups of neonates. CRP serum values were significantly higher in the infected neonates than in the asphyxiated or control subjects. Among the 54 asphyxiated and infected neonates, 15 were considered as severe cases and 39 as mild. The severe cases, at most time periods, had significantly higher IL-6, IL-1beta and sICAM-1 levels compared with the mild ones. Through receiver operating characteristic curves the cut-off points, sensitivities, and specificities for distinguishing neonates at risk or at high risk for brain damage were established.

CONCLUSION

Similar increases in serum levels of IL-6, IL-1beta and sICAM-1 were found in perinatally asphyxiated and infected neonates. As these increases correlated with the severity of the perinatal insults, neonates at high risk for brain damage might be detected.

How to leverage an endogenous immune defense mechanism: the example of granulocyte colony-stimulating factor

Our understanding of host defense has exploded during the past two decades. It is temping to take advantage of this knowledge by considering the modulation and control of these mechanisms as therapeutic options. In intensive care medicine, the aim is usually to block an overwhelming inflammatory response, which represents the "bad" side of the double-edged sword of host defense. The obvious danger of such treatment strategies is that impairing the inflammatory reaction means impairing host defense in patients exposed to infectious agents. The alternative approach, i.e., strengthening or supplementing favorable host defense mechanism, has so far been little explored clinically. Granulocyte colony-stimulating factor, the granulocyte colony-stimulating factor, combines the unique properties of an anti-infectious and an anti-inflammatory factor. This attractive profile has led us to various approaches to exploit these immunomodulatory activities. In a recently terminated, placebo-controlled, randomized study, we investigated if prophylactic treatment with rh granulocyte colony-stimulating factor (Filgrastim), at the time a risk can be anticipated such as before an operation, may offer protection from immunoinflammatory dyshomeostasis and thus lower the incidence of postoperative sepsis. Perioperative rh granulocyte colony-stimulating factor administration, compared with placebo treatment, resulted in the prevention of postoperative monocyte deactivation, conservation of an adequate Th1/Th2 ratio, as well as a considerable alleviation of the acute phase response. In parallel, there was a clear tendency toward lowering the rate of postoperative septic complications under the administration of Filgrastim.

Effects of hyperthermia and muramyl dipeptide on IL-1beta, IL-6, and mortality in a neonatal rat model

The mechanism of sudden infant death syndrome (SIDS) may be linked to an interaction between the SIDS risk factors of hyperthermia and infection, and between their effect on cytokine production and arousal. This study investigated the effects of hyperthermia and a surrogate of infection (muramyl dipeptide or MDP) on cytokine production and mortality in a neonatal rat model. Four temperature groups were studied: 34 degrees C (baseline), 38 degrees C, 39 degrees C, and 40 degrees C. Body temperatures of neonatal rat pups in the hyperthermic groups were raised and maintained at the desired temperature (38 degrees C, 39 degrees C, or 40 degrees C) for 1 h and then returned to the baseline temperature (34 degrees C) for a further hour. The heat source was a covered, heatable aluminum metal plate in a Perspex heating chamber. Intraperitoneal (IP) injection of 0.1 mL normal saline was given 30 min before the start to control for MDP (protocol A). Four equivalent treatment groups were pretreated with MDP (25 nmol/animal) instead of normal saline (protocol B). IP ketamine (55 mg/kg) was used for anesthesia during the experiments and for euthanasia. Blood was collected by direct cardiac puncture immediately after the 2-h experiments and assayed for the cytokines IL-6 and IL-1beta by ELISA. Hyperthermia significantly increased the production of IL-6 (p = 0.049) but not IL-1beta and significantly increased mortality. Administration of MDP significantly increased the IL-1beta production (p = 0.006) but not IL-6. Cox regression analysis showed that MDP in combination with hyperthermia had a significant effect on mortality in the neonatal rat. The risk of experiencing mortality was two and half times higher in the MDP group than in the non-MDP group (p = 0.016) [hazard ratio (95% confidence interval) = 2.66 (1.20-5.92)]. We conclude that hyperthermia and a surrogate of infection (MDP) influence cytokine production and that the combination of heat stress and MDP increases mortality in the neonatal rat.