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Neutrophils, as the first cellular line of innate host defense, employ phagocytosis and formation of neutrophil extracellular traps (NETs) to combat infections. Classical NET formation induced by phorbol myristate acetate requires several hours to complete. However, recent studies demonstrated rapid NET formation in neutrophils upon stimulation by platelets, Staphylococcus aureus or fungal products. Here we describe that antibody- or complement-induced phagocytosis triggers rapid NET formation. In contrast to classical NETosis, chemical inhibition of NADPH oxidase as well as using NADPH oxidase-deficient patient neutrophils did not affect rapid NET formation. Although phagocytosis and rapid NET formation may not be the prerequisite of each other, cooperation of phagocytosis and rapid NET formation may be essential to improve the efficiency of defense mechanisms in combating disseminating bacteria. Dissecting the differential mechanisms of NET formation is crucial to develop novel therapeutic strategies for infectious and auto-immune diseases where NETs play an essential role.

Infections are a leading cause of perinatal morbidity and mortality. The outstandingly high susceptibility to infections early in life is mainly attributable to the compromised state of the neonatal immune system. One important difference to the adult immune system is a bias towards T helper type 2 (Th2) responses in newborns. However, mechanisms regulating neonatal T‐cell responses are incompletely understood. Granulocytic myeloid‐derived suppressor cells (GR‐MDSC) are myeloid cells with a granulocytic phenotype that suppress various functions of other immune cells and accumulate under physiological conditions during pregnancy in maternal and fetal blood. Although it has been hypothesized that GR‐MDSC accumulation during fetal life could be important for the maintenance of maternal–fetal tolerance, the influence of GR‐MDSC on the immunological phenotype of neonates is still unclear. Here, we investigated the impact of GR‐MDSC isolated from cord blood (CB‐MDSC) on the polarization of Th cells. We demonstrate that CB‐MDSC inhibit Th1 responses and induced Th2 responses and regulatory T (Treg) cells. Th1 inhibition was cell‐contact dependent and occurred independent of other cell types, while Th2 induction was mediated independently of cell contact through expression of ArgI and reactive oxygen species by CB‐MDSC and partially needed the presence of monocytes. Treg cell induction by CB‐MDSC also occurred cell‐contact independently but was partially mediated through inducible nitric oxide synthase. These results point towards a role of MDSC in regulating neonatal immune responses. Targeting MDSC function in neonates could be a therapeutic opportunity to improve neonatal host defence.

Susceptibility to infection during the neonatal period and reduced control of inflammation in neonates are attributed to immunosuppression persisting from fetal life. Myeloid-derived suppressor cells (MDSCs) are immature myeloid progenitors with suppressive activity and increased numbers in cord blood. We hypothesized that MDSCs contribute to innate host defence in neonates, paralleled by anti-inflammatory signalling.Phagocytic activity, infection induced apoptosis, expression of B-cell lymphoma (Bcl)-2 family proteins, production of reactive oxygen species (ROS), cytokine production and T-cell suppression of neonatal granulocytic-MDSCs (G-MDSCs) after infection with Escherichia coli (E. coli) were compared to neonatal autologous mature polymorphonuclear leukocytes (PMNs). Phagocytic activity of G-MDSCs upon infection with E. coli was equal to that of mature PMNs, however, apoptosis of G-MDSCs was decreased. G-MDSCs showed enhanced Bcl-2-expression and lower ROS production compared to PMNs. Inhibition of Bcl-2 reduced apoptosis rates of G-MDSCs to that of mature PMNs. Induction of anti-inflammatory transforming growth factor beta (TGF-β) was enhanced, while pro-inflammatory IL-8 decreased in G-MDSCs compared to PMNs. Infected G-MDSCs strongly suppressed proliferation of T cells. We show a direct role of G-MDSCs for anti-bacterial host defence. Prolonged survival and anti-inflammatory capacity suggest that G-MDSCs are important for immune-regulation after bacterial infection.

Establishing and maintaining maternal-fetal tolerance is essential for a successful pregnancy; failure of immunological adaptation to pregnancy leads to severe complications such as abortion or preterm delivery. Myeloid-derived suppressor cells (MDSCs) are innate immune cells that suppress T-cell responses, expand during pregnancy and thus may play a role in tolerance induction. Human leucocyte antigen G (HLA-G) is a major histocompatibility complex (MHC) I molecule with immune-modulatory properties, which is expressed during pregnancy. Here, we investigated the impact of HLA-G on MDSCs accumulation and activation in pregnant women. We demonstrate that granulocytic MDSCs (GR-MDSCs) express receptors for HLA-G, namely immunoglobulin-like transcript (ILT) 2 and 4, and that ILT4-expression by GR-MDSCs is regulated during pregnancy. Stimulation with soluble HLA-G (sHLA-G) increased suppressive activity of GR-MDSCs, induced MDSCs from peripheral blood mononuclear cells (PBMCs) and led to phosphorylation of the signal transducer and activator of transcription 3 (STAT3) and induction of indoleamine-2,3-dioxygenase (IDO) in myeloid cells. Effects of sHLA-G on MDSC accumulation were mediated through ILT4. These results suggest an interaction between MDSCs and HLA-G in humans as a potential mechanism for maintaining maternal-fetal tolerance. Modulating MDSC function during pregnancy via HLA-G might provide new opportunities for a therapeutic manipulation of immunological pregnancy complications.

IntroductionThe healthy ‘eubiosis’ microbiome in infancy is regarded as the microbiome derived from term, vaginally delivered, antibiotic free, breastfed infants at 4–6 months. Dysbiosis is regarded as a deviation from a healthy state with reduced microbial diversity and deficient capacity to control drug-resistant organisms. Preterm infants are highly sensitive to early gut dysbiosis. Latter has been associated with sepsis and necrotising enterocolitis, but may also contribute to long-term health problems. Probiotics hold promise to reduce the risk for adverse short-term outcomes but the evidence from clinical trials remains inconclusive and none has directly assessed the effects of probiotics on the microbiome at high resolution.Methods and analysisA randomised, double blind, placebo-controlled study has been designed to assess the safety and efficacy of the probiotic mix of Bifidobacterium longum and infantis and Lactobacillus acidophilus in the prevention of gut dysbiosis in preterm infants between 28+0 and 32+6 weeks of gestation. The study is conducted in 18 German neonatal intensive care units. Between April 2018 and March 2020, 654 preterm infants of 28+0–32+6 weeks of gestation will be randomised in the first 48 hours of life to 28 days of once daily treatment with either probiotics or placebo. The efficacy endpoint is the prevention of gut dysbiosis at day 30 of life. A compound definition of gut dysbosis is used: (1) colonisation with multidrug-resistant organisms or gram-negative bacteria with high epidemic potential or (2) a significant deviation of the gut microbiota composition as compared with healthy term infants. Dysbiosis is determined by (1) conventional microbiological culture and (2) phylogenetic microbiome analysis by high-throughput 16S rRNA and metagenome sequencing. Persistence of dysbiosis will be assessed at 12-month follow-up visits. Side effects and adverse events related to the intervention will be recorded. Key secondary endpoint(s) are putative consequences of dysbiosis. A subgroup of infants will be thoroughly phenotyped for immune parameters using chipcytometry.Ethics and disseminationEthics approval was obtained in all participating sites. Results of the trial will be published in peer-review journals, at scientific meetings, on the website (www.primal-study.de) and via social media of parent organisations.Trial registration numberDRKS00013197; Pre-results.

Immunological pregnancy complications are a main challenge in reproductive medicine. Mechanisms regulating the adaptation of the maternal immune system to pregnancy are incompletely understood and therapeutic options limited. Myeloid derived suppressor cells (MDSC) are immune-modulatory cells expanding during healthy pregnancy and seem to play a crucial role for maternal-fetal tolerance. Recent studies showed that exosomes produced by MDSC have immune-modulatory effects corresponding to their parental cells under different pathological conditions. Here, we investigated immunological effects of exosomes of GR-MDSC during pregnancy. Isolated GR-MDSC exosomes from peripheral blood of pregnant women were tested for functionality in different in vitro assays. We show that GR-MDSC exosomes exhibited profound immune-modulatory effects such as suppression of T-cell proliferation, T helper 2 (Th2)-cell polarization, induction of regulatory T-cells and inhibition of lymphocyte cytotoxicity. Our results confirm that MDSC-derived exosomes functionally correspond to their parental cells and identify them as an interesting therapeutic target for immunological pregnancy complications.

Graft-versus-host disease (GvHD) is a major cause of morbidity and mortality after allogeneic hematopoietic cell transplantation. However, the pathophysiology of GvHD remains poorly understood. In this study, we analyzed the induction of Th17 cells by monocytes of patients with GvHD in vitro, demonstrating that monocytes isolated from patients with acute skin and intestinal GvHD stage I–IV and chronic GvHD induce significantly increased levels of Th17 cells compared with patients without GvHD. S100 proteins are known to act as innate amplifier of inflammation. We therefore investigated the presence of S100 proteins in the stool, serum, and bowel tissue of patients with GvHD and the influence of S100 proteins on the induction of Th17 cells. Elevated levels of S100 proteins could be detected in patients with acute GvHD, demonstrating the release of these phagocyte-specific proteins during GvHD. Furthermore, stimulation of monocytes with S100 proteins was found to promote Th17 development, emphasizing the role of S100 proteins in Th17-triggered inflammation. Altogether, our results indicate that induction of Th17 cells by activated monocytes and the stimulatory effects of proinflammatory S100 proteins might play a relevant role in the pathogenesis of acute GvHD. Regarding our data, S100 proteins might be novel markers for the diagnosis and follow-up of GvHD.

Immune tolerance toward the semiallogeneic fetus plays a crucial role in the maintenance of pregnancy. Myeloid-derived suppressor cells (MDSCs) are innate immune cells characterized by their ability to modulate T-cell responses. Recently, we showed that MDSCs accumulate in cord blood of healthy newborns, yet their role in materno-fetal tolerance remained elusive. In the present study, we demonstrate that MDSCs with a granulocytic phenotype (GR-MDSCs) are highly increased in the peripheral blood of healthy pregnant women during all stages of pregnancy compared with nonpregnant controls, whereas numbers of monocytic MDSCs were unchanged. GR-MDSCs expressed the effector enzymes arginase-I and iNOS, produced high amounts of ROS and efficiently suppressed T-cell proliferation. After parturition, GR-MDSCs decreased within a few days. In combination, our results show that GR-MDSCs expand in normal human pregnancy and may indicate a role for MDSCs in materno-fetal tolerance.

Summary Neonates show an impaired anti-microbial host defence, but the underlying immune mechanisms are not understood fully. Myeloid-derived suppressor cells (MDSCs) represent an innate immune cell subset characterized by their capacity to suppress T cell immunity. In this study we demonstrate that a distinct MDSC subset with a neutrophilic/granulocytic phenotype (Gr-MDSCs) is highly increased in cord blood compared to peripheral blood of children and adults. Functionally, cord blood isolated Gr-MDSCs suppressed T cell proliferation efficiently as well as T helper type 1 (Th1), Th2 and Th17 cytokine secretion. Beyond T cells, cord blood Gr-MDSCs controlled natural killer (NK) cell cytotoxicity in a cell contact-dependent manner. These studies establish neutrophilic Gr-MDSCs as a novel immunosuppressive cell subset that controls innate (NK) and adaptive (T cell) immune responses in neonates. Increased MDSC activity in cord blood might serve as key fetomaternal immunosuppressive mechanism impairing neonatal host defence. Gr-MDSCs in cord blood might therefore represent a therapeutic target in neonatal infections.

Septic diseases are characterized by an initial systemic, proinflammatory phase, followed by a period of anti-inflammation. In the context of the latter, monocytes have been described to display altered functions, including reduced TNF secretion and T cell-stimulating capacities in response to recall antigens. This hyporesponsiveness is supposed to be detrimental for coping with secondary infections. We here characterize bacterially reprogrammed PBMC-derived monocytes with special focus on their phagocytic activity. Hence, we have implemented a surrogate model of the early, postinflammatory period by exposing PBMCs to Escherichia coli on d0 and rechallenging them with bacteria on d2. This induced the emergence of a distinct monocytic phenotype with profound phagocytic impairments but a preserved ability for naïve T cell stimulation. The compromising effects on phagocytosis required the presence of bacteria and were not mimicked by TLR4 ligation or exposure to isolated cytokines alone. Moreover, the impairments were specific for the engulfment of bacteria and were coupled to a selective down-regulation of FcγR and SR expression. Intriguingly, this monocytic phenotype contributed to the stimulation of a TH17-polarized adaptive immune response in the context of secondary infection. Our findings extend the current knowledge of monocytic reprogramming and identify the phagocytic capacity of monocytes as a putative sepsis biomarker.

Prenatal exposure to parasite antigens or allergens will influence the profile and strength of postnatal immune responses, such contact may tolerize and increase susceptibility to future infections or sensitize to environmental allergens. Exposure in utero to parasite antigens will distinctly alter cellular gene expression in newborns. Gene microarrays were applied to study gene expression in umbilical cord blood cell (UCBC) from parasite-exposed (Para-POS) and non-exposed (Para-NEG) neonates. UCBC were activated with antigens of helminth (Onchocerca volvulus), amoeba (Entamoeba histolytica) or allergens of mite (Dermatophagoides farinae). When UCBC from Para-POS and Para-NEG newborns were exposed to helminth antigens or allergens consistent differences occurred in the expression of genes encoding for MHC class I and II alleles, signal transducers of activation and transcription (STATs), cytokines, chemokines, immunoglobulin heavy and light chains, and molecules associated with immune regulation (SOCS, TLR, TGF), inflammation (TNF, CCR) and apoptosis (CASP). Expression of genes associated with innate immune responses were enhanced in Para-NEG, while in Para-POS, the expression of MHC class II and STAT genes was reduced. Within functional gene networks for cellular growth, proliferation and immune responses, Para-NEG neonates presented with significantly higher expression values than Para-POS. In Para-NEG newborns, the gene cluster and pathway analyses suggested that gene expression profiles may predispose for the development of immunological, hematological and dermatological disorders upon postnatal helminth parasite infection or allergen exposure. Thus, prenatal parasite contact will sensitize without generating aberrant inflammatory immune responses, and increased pro-inflammatory but decreased regulatory gene expression profiles will be present in those neonates lacking prenatal parasite antigen encounter.

Allogeneic hematopoietic stem cell transplantation represents the most effective form of immunotherapy for chemorefractory diseases. However, animal models have been missing that allow evaluation of donor-patient–specific graft-versus-leukemia effects. Thus, we sought to establish a patient-tailored humanized mouse model that would result in long-term engraftment of various lymphocytic lineages and would serve as a donor-specific surrogate. Following transfer of donor-derived peripheral blood stem cells into NOD/SCID/IL-2Rγnull (NSG) mice with supplementation of human IL-7, we could demonstrate robust engraftment and multilineage differentiation comparable to earlier studies using cord blood stem cells. Phenotypical and functional analyses of lymphoid lineages revealed that >20 wk posthematopoietic stem cell transplantation, the majority of T lymphocytes consisted of memory-type CD4+ T cells capable of inducing specific immune functions, whereas CD8+ T cells were only present in low numbers. Analysis of NSG-derived NK cells revealed the expression of constitutively activated CD56brightCD16− killer Ig-like receptornegative NK cells that exhibited functional impairments. Thus, the data presented in this study demonstrate that humanized NSG mice can be successfully used to develop a xenotransplantation model that might allow patient-tailored treatment strategies in the future, but also highlight the need to improve this model, for example, by coadministration of differentiation-promoting cytokines and induction of human MHC molecules to complement existing deficiencies in NK and CD8+ T cell development.

Phagocytosis of apoptotic cells, e.g., neutrophils, by monocytes is essential for resolution of inflammation. Delayed removal leads to secondary necrosis, perpetuating inflammation, and tissue destruction. Common histologic features in neonatal chronic inflammatory disorders are an accumulation of apoptotic cells in inflamed tissues. We hypothesized that apoptotic cell removal by monocytes is compromised in newborns. PKH-26 labeled autologous or allogeneic apoptotic neutrophils were fed to monocytes of adult donors (PBMO) and cord blood (CBMO), and phagocytic activity was analyzed by flow cytometry and confocal microscopy. Relative mRNA-expression levels of 21 surface receptors and bridging molecules relevant for apoptotic cell removal were measured, as was postphagocytic IL-8 production upon LPS-stimulation. Compared with PBMO, CBMO exhibited a significantly diminished phagocytotic competence for autologous and allogeneic apoptotic neutrophils. mRNA-expression levels of milk fat globule-EGF factor 8 and T cell immunoglobulin- and mucin-domain-containing molecule, two crucial members of the phagocytic synapse of apoptotic cell removal, were reduced in CBMO. In PBMO, interaction with autologous apoptotic neutrophils reduced LPS-induced IL-8 production whereas it was enhanced in CBMO. Our data suggest a specific defect in CBMO during clearance of apoptotic neutrophils resulting in impaired anti-inflammatory capacity.

An imbalance in apoptosis or survival of immune cells plays an essential role in the pathophysiology of sepsis. Phagocytosis-induced cell death (PICD) is a common result of the pathogen-host cell interaction mediated by reactive oxygen species (ROS). Neonatal sepsis is frequently characterized by hyperinflammation. Cord blood monocytes (CBMO) are equivalent to monocytes of adults [peripheral blood monocytes (PBMO)], both in terms of phagocytosis and killing of Escherichia coli. We investigated whether CBMO are less sensitive toward PICD compared with PBMO. Monocytes were infected with green fluorescent protein (GFP)-labeled E. coli. Phagocytic activity, cell-count, Annexin V staining, hypoploid DNA content, CD95 and CD95L expression, and caspase-8 and -9 activities were analyzed by flow cytometry, ROS production by chemiluminescence, and CD95L mRNA expression by reverse-transcriptase polymerase chain reaction. With equal phagocytic activity and ROS production, PBMO cell count was decreased by 82 +/- 6% versus 28 +/- 8% for CBMO after infection. Annexin V binding was enhanced fivefold on PBMO; 56 +/- 15% of PBMO showed a hypodiploid DNA content compared with 9 +/- 6% of CBMO. Caspases CD95L and CD95L mRNA were up-regulated in PBMO. Our results indicate that CBMO are less sensitive toward E. coli-mediated PICD than PBMO. Modifying monocyte apoptosis may be a target for future interventions in sepsis.

Blood monocyte-derived macrophages invading the alveolus encounter pulmonary surfactant, a phospholipoprotein complex that changes composition during lung development. We tested the hypothesis that characteristic phosphatidylcholine (PC) components differentially influence macrophage phenotype and function, as determined by phagocytosis of green fluorescent protein-labeled Escherichia coli and alphaCD3-induced T cell proliferation. Human macrophages were exposed to surfactant (Curosurf(R)), to two of its characteristic phosphadidylcholine (PC) components (dipalmitoyl-PC and palmitoylmyristoyl-PC), and to a ubiquituous PC (palmitoyloleoyl-PC) as control. Interaction of Curosurf and PC species with macrophages was assessed using Lissaminetrade mark-dihexadecanoyl-phosphoethanolamine-labeled liposomes. Curosurf and both saturated surfactant PC species downregulated CD14 expression and upregulated CD206. HLA-DR and CD80 were upregulated by Curosurf and palmitoylmyristoyl-PC, whereas dipalmitoyl-PC showed no effect. The latter upregulated TLR2 and TLR4 expression, whereas Curosurf and palmitoylmyristoyl-PC had no effect. PC species tested were incorporated in comparable amounts by macrophages. Curosurf and PC species inhibited phagocytosis of E. coli. Scavenger receptor CD36, CD68, SR-A, and LOX-1 mRNA expression was upregulated by Curosurf, whereas PC species only upregulated SR-A. Curosurf and palmitoylmyristoyl-PC inhibited alphaCD3-induced T cell proliferation by 50%, whereas dipalmitoyl-PC and palmitoyloleoyl-PC showed no effect. These data identify individual surfactant PC species as modifiers of macrophage differentiation and suggest differential effects on innate and adaptive immune functions.

Tolerance induction toward the semiallogeneic fetus is crucial to enable a successful pregnancy; its failure is associated with abortion or preterm delivery. Skewing T cell differentiation toward a Th2-dominated phenotype seems to be pivotal in maternal immune adaption, yet underlying mechanisms are incompletely understood. Myeloid-derived suppressor cells (MDSCs) are innate immune cells that mediate T cell suppression and are increased in cord blood of healthy newborns and in peripheral blood of pregnant women. In this study, we demonstrate that granulocytic MDSCs (GR-MDSCs) accumulate in human placenta of healthy pregnancies but are diminished in patients with spontaneous abortions. Placental GR-MDSCs effectively suppressed T cell responses by expression of arginase I and production of reactive oxygen species and were activated at the maternal–fetal interface through interaction with trophoblast cells. Furthermore, GR-MDSCs isolated from placenta polarized CD4+ T cells toward a Th2 cytokine response. These results highlight a potential role of GR-MDSCs in inducing and maintaining maternal–fetal tolerance and suggest them as a promising target for therapeutic manipulation of pregnancy complications.

The expanding genus Bartonella includes zoonotic and human-specific pathogens that can cause a wide range of clinical manifestations. A productive infection allowing bacterial transmission by blood-sucking arthropods is marked by an intraerythrocytic bacteremia that occurs exclusively in specific human or animal reservoir hosts. Incidental human infection by animal-adapted bartonellae can cause disease without evidence for erythrocyte parasitism. A better understanding of the intraerythrocytic lifestyle of bartonellae may permit the design of strategies to control the reservoir and transmittable stages of these emerging pathogens. We have dissected the process of Bartonella erythrocyte parasitism in experimentally infected animals using a novel approach for tracking blood infections based on flow cytometric quantification of green fluorescent protein–expressing bacteria during their interaction with in vivo–biotinylated erythrocytes. Bacteremia onset occurs several days after inoculation by a synchronous wave of bacterial invasion into mature erythrocytes. Intracellular bacteria replicate until reaching a stagnant number, which is sustained for the remaining life span of the infected erythrocyte. The initial wave of erythrocyte infection is followed by reinfection waves occurring at intervals of several days. Our findings unravel a unique bacterial persistence strategy adapted to a nonhemolytic intracellular colonization of erythrocytes that preserves the pathogen for efficient transmission by blood-sucking arthropods.

Interactions between innate and adaptive immune functions in neonatal macrophages (MPhi) are still unclear. We therefore established a method to quantify bacterial phagocytosis and intracellular degradation, using green fluorescent protein (GFP)-labeled Escherichia coli in combination with phenotypic analysis. The kinetics of the proportion of phagocyting MPhi, phagocytosed bacteria per MPhi, and bacterial degradation were comparable for cord blood MPhi of term neonates and MPhi of healthy adults. Phenotyping revealed CD14 and CD16 to be down-modulated within minutes. GFP-labeled E. coli may be useful tools to further study MPhi subpopulations and determinants of phagocytosis in cord blood MPhi.

Neonates show sustained inflammation after a bacterial infection, which is associated with inflammatory diseases like bronchopulmonary dysplasia or periventricular leucomalacia. Physiologically, inflammation is terminated early after the removal of the invading pathogens by phagocytosis-induced cell death (PICD) of immune effector cells. Earlier results showed reduced PICD in neonatal monocytes. The underlying molecular mechanisms are unknown. We hypothesize that the reduced PICD in neonatal monocytes is regulated through the proteins of the B-cell lymphoma 2 (Bcl-2) protein family.mRNA and protein expression of Bcl-2 family proteins in cord blood and adult peripheral blood monocytes infected with Escherichia coli were analyzed by quantitative real-time PCR and flow cytometry and cytochrome c release by fluorescence microscopy.mRNA expression of antiapopototic Bcl-xL was upregulated in cord blood monocytes (CBMO), whereas proapoptotic Bim tended to be higher in peripheral blood monocytes (PBMO). Upon infection, Bax was more strongly expressed in PBMO compared with CBMO. The pro/antiapoptotic balance was skewed toward survival in CBMO and apoptosis in PBMO. Cytochome c release into the cytosol was enhanced in PBMO compared with CBMO.Bcl-2 proteins are involved in reduced PICD in neonatal monocytes. These findings are another step toward the understanding of sustained inflammation in neonates.

PLoS one 8(1), e53589 (2013). doi:10.1371/journal.pone.0053589, Published by PLoS ; [S.l.] : PubMed Central [u.a.], Lawrence, Kan.

Background Preterm delivery is a leading cause of neonatal morbidity and death. It often results from chorioamnionitis, which is a complication of bacterial vaginosis. Probiotics are effective in the treatment of bacterial vaginosis in women who were not pregnant; studies in pregnant woman are missing. Objective The purpose of this study was to evaluate whether an oral probiotic food supplement supports the maintenance or restoration of a normal vaginal microbiota during pregnancy. Study Design We conducted a randomized, placebo-controlled, triple-blind, parallel group trial. Oral Lactobacillus rhamnosus GR-1and L reuteri RC-14 (10 9 colony-forming units) or placebo were administered for 8 weeks to women with Results Three hundred twenty pregnant women were enrolled. Vaginal swabs were analyzed from 290 women before and 271 women after intervention. The proportion of normal vaginal microbiota decreased from 82.6 to 77.8% in the treatment group and from 79.1 to 74.3% in the placebo group, with no significant difference across groups after intervention ( P =.297). Conclusion Oral probiotics may be suitable for implementation in antenatal care but, as administered here, had no effect on vaginal health during mid gestation. Other application routes or probiotic preparations may be more effective in supporting vaginal microbiota during pregnancy.

Trials of immune-modulating drugs in septic patients have mostly failed to demonstrate clinical efficacy. Thus, we sought to generate a surrogate model of myelomonocytic lineage differentiation that would potentially allow sepsis induction and preclinical testing of anti-inflammatory drugs. Comparing transplantation of cord blood-derived stem cells in neonatal NOD/SCID/IL2Rγ(null) (neonatal huNSG) mice with transplantation of adult peripheral mobilized stem cells into adult NSG (adult huNSG) recipients, we demonstrate that myelomonocytic lineage differentiation in neonatal huNSG mice is retarded and monocytes are phenotypically immature with respect to HLA-DR expression and the emergence of CD80(+)CD86(+) monocytes. Functionally, neonatal huNSG mice were less sensitive toward interferon-γ-induced upregulation of CD86 and exhibited a reduced T-cell stimulating capacity when compared with adult huNSG mice, whereas the phagocytic activity and the ability for cytokine secretion were mature. However, comparison of these data with data obtained from human neonates indicate that absence of the CD80(+)CD86(+) population and the reduced T-cell stimulating capacity of neonatal huNSG monocytes resemble functional immaturities observed in human neonatal monocytes. Thus, these two mouse models might well serve as 2 independent surrogate models for studying the neonatal myelomonocytic lineage differentiation or for testing the efficacy of immunomodulatory drugs on functionally mature monocytes.

SUMMARY: BACKGOUND: The aim of this study was to investigate C-reactive protein (CRP), measured by a highly sensitive method (hsCRP) in non-infected newborns and in those with suspected early onset bacterial infection (EOBI) as well as to test whether EOBI would be detectable earlier by hsCRP than by a nephelometric CRP (nsCRP) assay (thresholds10 mg/l) or IL-8. PATIENTS AND METHODS: 106 neonates with signs of infection comprised the suspected EOBI group. 134 neonates with risk factors but confirmed exclusion of EOBI served as non-infected controls. RESULTS: In the non-infected group, hsCRP in the first 6 h after birth was low (0.7 mg/l; SD 0.16 mg/l) but showed an increase to 4.11 mg/l (SD 3.33 mg/l) at 72 h (p0.001 vs. 6 h). The sensitivity of hsCRP (cut-off 0.3 mg/l) vs. nsCRP for EOBI was 0.46 vs. 0.23 at 6 h after clinical suspicion. Of all parameters measured, IL-8 had the highest sensitivity and specificity to detect EOBI at 6 h (0.60 and 0.90), but declined after 12 and 24 h. CONCLUSION: Lowering the CRP detection threshold by a highly sensitive assay did not improve diagnostic accuracy for EOBI.

Graft-versus-host disease (GvHD) is one of the major live threatening complications of allogeneic hematopoietic cell transplantation (HCT). The pathophysiology of GvHD is complex and not fully understood yet. However, it has been shown that Th17 cells play an important role in the pathogenesis of acute and chronic GvHD. Therefore, the development of Th17 cells in patients with GvHD was further investigated in the present study. The influence of monocytes and their activation with proinflammatory S100 proteins and 90 kDa heat shock protein (Hsp90) on the induction of Th17 cells was examined. Furthermore, the suitability of S100 proteins as diagnostic markers for intestinal GvHD was analyzed. In the present study, it could be demonstrated that monocytes from patients with acute and chronic skin or intestinal GvHD grade I-IV (n=13) induced significant higher percentages of Th17 cells compared to monocytes from healthy donors (n=32) or patients without GvHD at several timepoints after HCT (n=21) (p In conclusion, our findings suggest that monocytes may play a major role in the pathogenesis of GvHD by triggering the induction of Th17 cells. Monocyte-induced Th17 cell development could further be enhanced by stimulation of monocytes with purified S100 proteins. The chaperone Hsp90 could be an important regulator in monocyte-induced development of Th17 cells and therefore be a therapeutic target for GvHD. Furthermore, S100 proteins might be novel diagnostic markers in intestinal tissue and potential non-invasive markers in the stool for intestinal GvHD. Disclosures: No relevant conflicts of interest to declare.