Hyperoxia/Hypoxia Exposure Primes a Sustained Pro-Inflammatory Profile of Preterm Infant Macrophages Upon LPS Stimulation.

Preterm infants are highly susceptible to sustained lung inflammation, which may be triggered by exposure to multiple environmental cues such as supplemental oxygen (O2) and infections. We hypothesized that dysregulated macrophage (MФ) activation is a key feature leading to inflammation-mediated development of bronchopulmonary dysplasia (BPD) in preterm infants. Therefore, we aimed to determine age-dependent differences in immune responses of monocyte-derived MФ comparing cord blood samples derived from preterm (n=14) and term (n=19) infants as well as peripheral blood samples from healthy adults (n=17) after lipopolysaccharide (LPS) exposure. Compared to term and adult MФ, LPS-stimulated preterm MФ showed an enhanced and sustained pro-inflammatory immune response determined by transcriptome analysis, cytokine release inducing a RORC upregulation due to T cell polarization of neonatal T cells, and TLR4 surface expression. In addition, a double-hit model was developed to study pulmonary relevant exposure factors by priming MФ with hyperoxia (O2 = 65%) or hypoxia (O2 = 3%) followed by lipopolysaccharide (LPS, 100ng/ml). When primed by 65% O2, subsequent LPS stimulation in preterm MФ led to an exaggerated pro-inflammatory response (e.g. increased HLA-DR expression and cytokine release) compared to LPS stimulation alone. Both, exposure to 65% or 3% O2 together with subsequent LPS stimulation, resulted in an exaggerated pro-inflammatory response of preterm MФ determined by transcriptome analysis. Downregulation of two major transcriptional factors, early growth response gene (Egr)-2 and growth factor independence 1 (Gfi1), were identified to play a role in the exaggerated pro-inflammatory response of preterm MФ to LPS insult after priming with 65% or 3% O2. Preterm MФ responses to LPS and hyperoxia/hypoxia suggest their involvement in excessive inflammation due to age-dependent differences, potentially mediated by downregulation of Egr2 and Gfi1 in the developing lung.

Aberrant gut-microbiota-immune-brain axis development in premature neonates with brain damage.

Premature infants are at substantial risk for suffering from perinatal white matter injury. Though the gut microbiota has been implicated in early-life development, a detailed understanding of the gut-microbiota-immune-brain axis in premature neonates is lacking. Here, we profiled the gut microbiota, immunological, and neurophysiological development of 60 extremely premature infants, which received standard hospital care including antibiotics and probiotics. We found that maturation of electrocortical activity is suppressed in infants with severe brain damage. This is accompanied by elevated γδ T cell levels and increased T cell secretion of vascular endothelial growth factor and reduced secretion of neuroprotectants. Notably, Klebsiella overgrowth in the gut is highly predictive for brain damage and is associated with a pro-inflammatory immunological tone. These results suggest that aberrant development of the gut-microbiota-immune-brain axis may drive or exacerbate brain injury in extremely premature neonates and represents a promising target for novel intervention strategies.

Effects of Total Enteral Nutrition on Early Growth, Immunity, and Neuronal Development of Preterm Infants.

The feeding of colostrum and mother's transitional milk improves immune protection and neurodevelopmental outcomes. It also helps with gut maturation and decreases the risks of infection. The supply of nutrients from human milk (HM) is not adequate for preterm infants, even though preterm mother's milk contains higher concentrations of protein, sodium, zinc, and calcium than mature HM. The human milk fortifiers, particularly those with protein, calcium, and phosphate, should be used to supplement HM to meet the necessities of preterm infants. The management of fluid and electrolytes is a challenging aspect of neonatal care of preterm infants. Trace minerals such as iron, zinc, copper, iodine, manganese, molybdenum, selenium, chromium, and fluoride are considered essential for preterm infants. Vitamins such as A, D, E, and K play an important role in the prevention of morbidities, such as bronchopulmonary dysplasia, retinopathy of prematurity, and intraventricular hemorrhage. Therefore, supplementation of HM with required nutrients is recommended for all preterm infants.

Estradiol correlates with the accumulation of Monocytic Myeloid-Derived Suppressor Cells in Pre-term birth: A possible explanation of immune suppression in pre-term babies.

Synergistic interplay of immune endocrine interaction is prerequisite for an effective maternal fetal tolerance. Pre-term birth (PTB) may be a consequence of altered immune-endocrine crosstalk during third trimester resulting in early breakdown of this tolerance. Myeloid derived suppressor cells (MDSCs), a heterogenous population of immature immune cells are increased in pregnant women and healthy newborns, but their role in PTB still remains obscure. We now report that granulocytic MDSCs (G-MDSCs) is decreased in women delivering prematurely, suggesting their potential role in maintaining maternal fetal tolerance. Interestingly, in contrast statistically significant increase in MDSCs and monocytic MDSCs (M-MDSCs) along with positive correlation with cord serum estradiol (E2), and overexpressed ER-α in placental tissue suggested E2 mediated accumulation of M-MDSCs in PTB babies. MDSCs mediated immune suppression is accompanied with subsequent decline in total T cells and its subtypes: Th and Tc in PTB babies, which signifies their potential contribution towards the impaired immune system of PTB babies.

Lung CD103+dendritic cells and Clec9a signaling are required for neonatal hyperoxia-induced inflammatory responses to rhinovirus infection.

Premature infants, especially those with bronchopulmonary dysplasia (BPD), develop recurrent severe respiratory viral illnesses. We have shown that hyperoxic exposure of immature mice, a model of BPD, increases lung IL-12-producing Clec9a+ CD103+ dendritic cells (DCs), pro-inflammatory responses, and airway hyperreactivity following rhinovirus (RV) infection. However, the requirement for CD103+ DCs and Clec9a, a DAMP receptor that binds necrotic cell cytoskeletal filamentous actin (F-actin), for RV-induced inflammatory responses has not been demonstrated. To test this, 2-day-old C57BL/6J, CD103+ DC-deficient Batf3-/- or Clec9agfp-/- mice were exposed to normoxia or hyperoxia for 14 days. Also, selected mice were treated with neutralizing antibody against CD103. Immediately after hyperoxia, the mice were inoculated with RV intranasally. We found that compared with wild-type mice, hyperoxia-exposed Batf3-/- mice showed reduced levels of IL-12p40, IFN-γ, and TNF-α, fewer IFN-γ-producing CD4+ T cells, and decreased airway responsiveness following RV infection. Similar effects were observed in anti-CD103-treated and Clec9agfp-/- mice. Furthermore, hyperoxia increased airway dead cell number and extracellular F-actin levels. Finally, studies in preterm infants with respiratory distress syndrome showed that tracheal aspirate CLEC9A expression positively correlated with IL12B expression, consistent with the notion that CLEC9A+ cells are responsible for IL-12 production in humans as well as mice. We conclude that CD103+ DCs and Clec9a are required for hyperoxia-induced pro-inflammatory responses to RV infection. In premature infants, Clec9a-mediated activation of CD103+ DCs may promote pro-inflammatory responses to viral infection, thereby driving respiratory morbidity.

The association of γδ-T cells with bronchopulmonary dysplasia in premature infants.

BACKGROUND: As the survival rate of premature infants increases, the incidence of bronchopulmonary dysplasia (BPD), a chronic complication of premature infants, is also higher than before. The pathogenesis of BPD is complicated, and immune imbalance and inflammatory response may play important roles in it. OBJECTIVE: To investigate the correlation between lymphocyte subsets in peripheral blood, especially γδ-T cells, and BPD of preterm infants. MATERIALS AND METHOD: The study was carried out with the peripheral blood of premature infants (GA < 32 weeks, BW < 1500 g), which were collected at 24 h or 3-4 weeks after birth. The infants were divided into non-BPD groups and BPD groups that were classified as mild or moderate and severe in preterm infants based on the magnitude of respiratory support at 28 days age and 36 weeks postmenstrual age. The γδ-T, CD3+, CD4+, CD8+ and total lymphocyte subsets in peripheral blood were detected by flow cytometry. RESULTS: The percentages of T lymphocyte subsets in peripheral blood were not different between BPD and non-BPD within 24 h after birth. And no significant difference was found in T lymphocyte subsets among neonates with BPD of different severities. However, the infants who developed BPD had a significant increase in γδ-T cells compared to non-BPD ones within 3-4 weeks after birth. CONCLUSIONS: It seems that γδ-T cells in peripheral blood are correlated with BPD. However, the causality of BPD and various lymphocytes remains unclear, which need to be further studied.

Increased Regulatory T Cells Precede the Development of Bronchopulmonary Dysplasia in Preterm Infants.

Regulatory T cells (Tregs) are important for the ontogenetic control of immune activation and tissue damage in preterm infants. However, the role of Tregs for the development of bronchopulmonary dysplasia (BPD) is yet unclear. The aim of our study was to characterize CD4+ CD25+ forkhead box protein 3 (FoxP3)+ Tregs in peripheral blood of well-phenotyped preterm infants (n = 382; 23 + 0 - 36 + 6 weeks of gestational age) with a focus on the first 28 days of life and the clinical endpoint BPD (supplemental oxygen for longer than 28 days of age). In a subgroup of preterm infants, we characterized the immunological phenotype of Tregs (n = 23). The suppressive function of Tregs on CD4+CD25- T cells was compared in preterm, term and adult blood. We observed that extreme prematurity was associated with increased Treg frequencies which peaked in the second week of life. Independent of gestational age, increased Treg frequencies were noted to precede the development of BPD. The phenotype of preterm infant Tregs largely differed from adult Tregs and displayed an overall naïve Treg population (CD45RA+/HLA-DR-/Helios+), especially in the first days of life. On day 7 of life, a more activated Treg phenotype pattern (CCR6+, HLA-DR+, and Ki-67+) was observed. Tregs of preterm neonates had a higher immunosuppressive capacity against CD4+CD25- T cells compared to the Treg compartment of term neonates and adults. In conclusion, our data suggest increased frequencies and functions of Tregs in preterm neonates which display a distinct phenotype with dynamic changes in the first weeks of life. Hence, the continued abundance of Tregs may contribute to sustained inflammation preceding the development of BPD. Functional analyses are needed in order to elucidate whether Tregs have potential as future target for diagnostics and therapeutics.

S100A8 and S100A9 Are Important for Postnatal Development of Gut Microbiota and Immune System in Mice and Infants.

BACKGROUND & AIMS: After birth, the immune system matures via interactions with microbes in the gut. The S100 calcium binding proteins S100A8 and S100A9, and their extracellular complex form, S100A8-A9, are found in high amounts in human breast milk. We studied levels of S100A8-A9 in fecal samples (also called fecal calprotectin) from newborns and during infancy, and their effects on development of the intestinal microbiota and mucosal immune system. METHODS: We collected stool samples (n = 517) from full-term (n = 72) and preterm infants (n = 49) at different timepoints over the first year of life (days 1, 3, 10, 30, 90, 180, and 360). We measured levels of S100A8-A9 by enzyme-linked immunosorbent assay and analyzed fecal microbiomes by 16S sRNA gene sequencing. We also obtained small and large intestine biopsies from 8 adults and 10 newborn infants without inflammatory bowel diseases (controls) and 8 infants with necrotizing enterocolitis and measured levels of S100A8 by immunofluorescence microscopy. Children were followed for 2.5 years and anthropometric data and medical information on infections were collected. We performed studies with newborn C57BL/6J wild-type and S100a9-/- mice (which also lack S100A8). Some mice were fed or given intraperitoneal injections of S100A8 or subcutaneous injections of Staphylococcus aureus. Blood and intestine, mesenterial and celiac lymph nodes were collected; cells and cytokines were measured by flow cytometry and studied in cell culture assays. Colon contents from mice were analyzed by culture-based microbiology assays. RESULTS: Loss of S100A8 and S100A9 in mice altered the phenotypes of colonic lamina propria macrophages, compared with wild-type mice. Intestinal tissues from neonatal S100-knockout mice had reduced levels of CX3CR1 protein, and Il10 and Tgfb1 mRNAs, compared with wild-type mice, and fewer T-regulatory cells. S100-knockout mice weighed 21% more than wild-type mice at age 8 weeks and a higher proportion developed fatal sepsis during the neonatal period. S100-knockout mice had alterations in their fecal microbiomes, with higher abundance of Enterobacteriaceae. Feeding mice S100 at birth prevented the expansion of Enterobacteriaceae, increased numbers of T-regulatory cells and levels of CX3CR1 protein and Il10 mRNA in intestine tissues, and reduced body weight and death from neonatal sepsis. Fecal samples from term infants, but not preterm infants, had significantly higher levels of S100A8-A9 during the first 3 months of life than fecal samples from adults; levels decreased to adult levels after weaning. Fecal samples from infants born by cesarean delivery had lower levels of S100A8-A9 than from infants born by vaginal delivery. S100 proteins were expressed by lamina propria macrophages in intestinal tissues from infants, at higher levels than in intestinal tissues from adults. High fecal levels of S100 proteins, from 30 days to 1 year of age, were associated with higher abundance of Actinobacteria and Bifidobacteriaceae, and lower abundance of Gammaproteobacteria-particularly opportunistic Enterobacteriaceae. A low level of S100 proteins in infants' fecal samples associated with development of sepsis and obesity by age 2 years. CONCLUSION: S100A8 and S100A9 regulate development of the intestinal microbiota and immune system in neonates. Nutritional supplementation with these proteins might aide in development of preterm infants and prevent microbiota-associated disorders in later years.

Vacunas e inmunizaciones en recién nacidos y recién nacidos prematuros / Vaccines in newborn and preterm infants

El recién nacido de pretérmino (RNPT), especialmente el menor de 32 semanas de edad gestacional, presenta un mayor riesgo de adquirir infecciones y que estas sean de curso más grave respecto a los recién nacidos de término (RNT), debido, entre otros factores a una inmadurez de varios componentes del sistema inmune. Muchas de estas infecciones son inmunoprevenibles por vacunas disponibles en nuestro medio y la recomendación actual es vacunar a los lactantes nacidos de pretérmino o bajo peso, salvo pocas excepciones, con todas las vacunas rutinariamente recomendadas según su edad cronológica al igual que un RNT. Sin embrago, en muchas oportunidades se observa un retraso en los calendarios de inmunización de estos lactantes principalmente por las aprehensiones respecto a la inmunogenicidad y seguridad de las vacunas en esta población. El objetivo de este artículo es revisar la evidencia disponible respecto a la eficacia y seguridad de las vacunas habitualmente utilizadas en lactantes, enfocados en los RNPT.

Preterm infants, especially those born with less than 32 weeks of gestational age, have a higher risk of acquiring serious infections compared to term infants due among other factors, to a decrease in several components of the immune system. Many of these infections are immunopreventable by vaccines available in our country. The current recommendation is to vaccinate all preterm or low weight born infants with few exceptions, using vaccines routinely recommended according to their chronological age just as term infants. However, on many occasions there is a delay in the immunization schedules of these infants mainly due to the apprehensions regarding the immunogenicity and safety of vaccines in this population. The aim of this article is to review the available evidence regarding the efficacy and safety of vaccines commonly used in preterm infants.

Dysregulated Mucosal Immunity and Associated Pathogeneses in Preterm Neonates.

Many functions of the immune system are impaired in neonates, allowing vulnerability to serious bacterial, viral and fungal infections which would otherwise not be pathogenic to mature individuals. This vulnerability is exacerbated in compromised newborns such as premature neonates and those who have undergone surgery or who require care in an intensive care unit. Higher susceptibility of preterm neonates to infections is associated with delayed immune system maturation, with deficiencies present in both the innate and adaptive immune components. Here, we review recent insights into early life immunity, and highlight features associated with compromised newborns, given the challenges of studying neonatal immunity in compromised neonates due to the transient nature of this period of life, and logistical and ethical obstacles posed by undertaking studies newborns and infants. Finally, we highlight how the unique immunological characteristics of the premature host play key roles in the pathogenesis of diseases that are unique to this population, including necrotizing enterocolitis and the associated sequalae of lung and brain injury.

Cytokine Expression by Human Macrophage-Like Cells Derived from the Monocytic Cell Line THP-1 Differs Between Treatment With Milk from Preterm- and Term-Delivering Mothers and Pasteurized Donor Milk.

Immunomodulatory proteins from human milk may enhance the protection and development of the infant's gut. This study compared the immunomodulatory effects of treatment with milk from preterm-(PM) and term-delivering (TM) mothers and pasteurized donor milk (DM) on cytokine gene expression in human macrophage-like cells derived from the monocytic cell line THP-1. The gene expression of tumor necrosis factor-α (TNF-α), interleukin (IL)-6, IL-12 (p40), IL-10 and GAPDH in macrophages treated with PM, TM and DM at steady and activated (inflammatory) states were measured using real-time reverse transcription-polymerase chain reaction. TNF-α and IL-6 in macrophages (both states) with DM were higher than PM or TM. IL-10 in steady state macrophages with DM was higher than PM whereas DM increased IL-10 in activated macrophages compared with TM. TM increased IL-6 and IL-12 (p40) in steady state macrophages compared with PM. IL-12 (p40) in activated macrophages with TM was higher than PM. IL-10 in steady state macrophages with TM was higher than PM. These results suggest that DM induces higher gene expression of pro-inflammatory and anti-inflammatory cytokines in macrophages compared with PM or TM. PM reduced gene expression of pro-inflammatory cytokines compared with TM, which may decrease the development of necrotizing enterocolitis and systematic inflammation.

Maternal activation of the EGFR prevents translocation of gut-residing pathogenic Escherichia coli in a model of late-onset neonatal sepsis.

Late-onset sepsis (LOS) is a highly consequential complication of preterm birth and is defined by a positive blood culture obtained after 72 h of age. The causative bacteria can be found in patients' intestinal tracts days before dissemination, and cohort studies suggest reduced LOS risk in breastfed preterm infants through unknown mechanisms. Reduced concentrations of epidermal growth factor (EGF) of maternal origin within the intestinal tract of mice correlated to the translocation of a gut-resident human pathogen Escherichia coli, which spreads systemically and caused a rapid, fatal disease in pups. Translocation of Escherichia coli was associated with the formation of colonic goblet cell-associated antigen passages (GAPs), which translocate enteric bacteria across the intestinal epithelium. Thus, maternally derived EGF, and potentially other EGFR ligands, prevents dissemination of a gut-resident pathogen by inhibiting goblet cell-mediated bacterial translocation. Through manipulation of maternally derived EGF and alteration of the earliest gut defenses, we have developed an animal model of pathogen dissemination which recapitulates gut-origin neonatal LOS.

Intravenous immunoglobulin for preventing infection in preterm and/or low birth weight infants.

BACKGROUND: Nosocomial infections continue to be a significant cause of morbidity and mortality among preterm and/or low birth weight (LBW) infants. Preterm infants are deficient in immunoglobulin G (IgG); therefore, administration of intravenous immunoglobulin (IVIG) may have the potential of preventing or altering the course of nosocomial infections. OBJECTIVES: To use systematic review/meta-analytical techniques to determine whether IVIG administration (compared with placebo or no intervention) to preterm (< 37 weeks' postmenstrual age (PMA) at birth) or LBW (< 2500 g birth weight) infants or both is effective/safe in preventing nosocomial infection. SEARCH METHODS: For this update, MEDLINE, EMBASE, CINAHL, The Cochrane Library, Controlled Trials, ClinicalTrials.gov and PAS Abstracts2view were searched in May 2013. SELECTION CRITERIA: We selected randomised controlled trials (RCTs) in which a group of participants to whom IVIG was given was compared with a control group that received a placebo or no intervention for preterm (< 37 weeks' gestational age) and/or LBW (< 2500 g) infants. Studies that were primarily designed to assess the effect of IVIG on humoral immune markers were excluded, as were studies in which the follow-up period was one week or less. DATA COLLECTION AND ANALYSIS: Data collection and analysis was performed in accordance with the methods of the Cochrane Neonatal Review Group. MAIN RESULTS: Nineteen studies enrolling approximately 5000 preterm and/or LBW infants met inclusion criteria. No new trials were identified in May 2013. When all studies were combined, a significant reduction in sepsis was noted (typical risk ratio (RR) 0.85, 95% confidence interval (CI) 0.74 to 0.98; typical risk difference (RD) -0.03, 95% CI 0.00 to -0.05; number needed to treat for an additional beneficial outcome (NNTB) 33, 95% CI 20 to infinity), and moderate between-study heterogeneity was reported (I2 54% for RR, 55% for RD). A significant reduction of one or more episodes was found for any serious infection when all studies were combined (typical RR 0.82, 95% CI 0.74 to 0.92; typical RD -0.04, 95% CI -0.02 to -0.06; NNTB 25, 95% CI 17 to 50), and moderate between-study heterogeneity was observed (I2 50% for RR, 62% for RD). No statistically significant differences in mortality from all causes were noted (typical RR 0.89, 95% CI 0.75 to 1.05; typical RD -0.01, 95% CI -0.03 to 0.01), and no heterogeneity for RR (I2 = 21%) or low heterogeneity for RD was documented (I2 = 28%). No statistically significant difference was seen in mortality from infection; in incidence of necrotizing enterocolitis (NEC), bronchopulmonary dysplasia (BPD) or intraventricular haemorrhage (IVH) or in length of hospital stay. No major adverse effects of IVIG were reported in any of these studies. AUTHORS' CONCLUSIONS: IVIG administration results in a 3% reduction in sepsis and a 4% reduction in one or more episodes of any serious infection but is not associated with reductions in other clinically important outcomes, including mortality. Prophylactic use of IVIG is not associated with any short-term serious side effects. The decision to use prophylactic IVIG will depend on the costs and the values assigned to the clinical outcomes. There is no justification for conducting additional RCTs to test the efficacy of previously studied IVIG preparations in reducing nosocomial infections in preterm and/or LBW infants.

Rotavirus vaccination in the neonatal intensive care units: where are we? A rapid review of recent evidence.

PURPOSE OF REVIEW: Rotavirus is a leading cause of viral acute gastroenteritis in infants. Neonates hospitalized in neonatal intensive care units (NICUs) are at risk of rotavirus infections with severe outcomes. The administration of rotavirus vaccines is only recommended, in the United States and Canada, upon discharge from the NICU despite rotavirus vaccines being proven well tolerated and effective in these populations, because of risks of live-attenuated vaccine administration in immunocompromised patients and theoretical risks of rotavirus vaccine strains shedding and transmission.We aimed to summarize recent evidence regarding rotavirus vaccine administration in the NICU setting and safety of rotavirus vaccines in preterm infants. METHODS: We conducted a rapid review of the literature from the past 10 years, searching Medline and Embase, including all study types except reviews, reporting on rotavirus vaccines 1 and 5; NICU setting; shedding or transmission; safety in preterm. One reviewer performed data extraction and quality assessment. RECENT FINDINGS: Thirty-one articles were analyzed. Vaccine-derived virus shedding following rotavirus vaccines existed for nearly all infants, mostly during the first week after dose 1, but with rare transmission only described in the household setting. No case of transmission in the NICU was reported. Adverse events were mild to moderate, occurring in 10-60% of vaccinated infants. Extreme premature infants or those with underlying gastrointestinal failure requiring surgery presented with more severe adverse events. SUMMARY: Recommendations regarding rotavirus vaccine administration in the NICU should be reassessed in light of the relative safety and absence of transmission of rotavirus vaccine strains in the NICU.

Cyclic AMP in human preterm infant blood is associated with increased TLR-mediated production of acute-phase and anti-inflammatory cytokines in vitro.

BACKGROUND: Preterm infants are at high risk of infection and have distinct pathogen recognition responses. Suggested mechanisms include soluble mediators that enhance cellular levels of cAMP. The aim of this study was to assess the relationship between blood cAMP concentrations and TLR-mediated cytokine production in infants during the first month of life. METHODS: Cord and serial peripheral blood samples (days of life 1-28) were obtained from a cohort of very preterm (<30 weeks' gestational age) and term human infants. Whole-blood concentrations of cAMP and FSL-1 and LPS in vitro stimulated cytokine concentrations were measured by ELISA and multiplex bead assay. RESULTS: cAMP concentrations were higher in cord than in peripheral blood, higher in cord blood of female preterm infants, and lower at Days 1 and 7 in infants exposed to chorioamnionitis, even after adjusting for leukocyte counts. TLR2 and TLR4-mediated TNF-α, IL-1ß, IL-6, IL-12p70, and IL-10 production in vitro increased over the first month of life in preterm infants and were positively correlated with leukocyte-adjusted cAMP levels and reduced by exposure to chorioamnionitis. CONCLUSIONS: The ontogeny of blood cAMP concentrations and associations with chorioamnionitis and TLR-mediated production of cytokines suggest that this secondary messenger helps shape distinct neonatal pathogen responses in early life.

Two pediatric cases of Pneumocystis jirovecii pneumonia diagnosed by polymerase chain reaction of gastric lavage.

Detecting Pneumocystis jirovecii by bronchoalveolar lavage or lung biopsy is the gold standard for diagnosis of P. jirovecii pneumonia (PJP); however, these techniques are not always applicable in children because of their high invasiveness. We report two pediatric cases of PJP diagnosed by polymerase chain reaction (PCR) of gastric lavage that were successfully treated. To date, there are no reported cases of using PCR of gastric lavage to diagnose PJP. On the day of PJP onset, both the infants required respiratory support and infiltrative shadows were observed in both lung fields on chest radiography. Furthermore, their (1 â†’ 3)-ß-D glucan levels were elevated. P. jirovecii was detected by PCR of gastric lavage and trimethoprim-sulfamethoxazole was administered for 3 weeks, following which their condition improved. They were long-term steroid users, but without any prophylaxis. PCR of gastric lavage in cases of suspected PJP may help in confirming the diagnosis in children who have mild to moderate airway symptoms, or have difficulty with invasive examination like bronchoscopy.

Enhancement of immune response mediated by oropharyngeal colostrum administration in preterm neonates.

BACKGROUND: The immune system of preterm infants is immature, being a significant cause of morbidity and mortality, particularly in the preterm infant. Oropharyngeal colostrum administration could be an immunomodulatory aid. Our aim was to evaluate the effect of oropharyngeal colostrum on the serum levels of immunoglobulins, lactoferrin, and resistin during the first month of life and to track the clinical outcome of the neonates. METHODS: One hundred preterm neonates born at <32 weeks of gestation and/or weighing < 1500 g and assisted in the Neonatal Intensive Care Unit were enrolled and divided into two groups: colostrum (n = 48) and control (n = 52). The subjects assigned to the colostrum group received 0.2 mL of colostrum (oropharyngeal route) every 4 hours for the first 15 days of life, and if mothers have inability to breastfeed, they were included in the control group (no oropharyngeal colostrum). Serum concentrations of IgA, IgM, and IgG1, lactoferrin, and resistin were assessed in both groups at 1, 3, 15, and 30 days of life. Clinical data during hospitalization were collected. RESULTS: IgA and IgM increased in preterm neonates who were administered colostrum for 15 and 30 days. Lactoferrin increased after 30 days, and resistin increased after 15 days of supplying oropharyngeal colostrum. The colostrum group underwent full enteral nutrition before, and no differences were observed in the common neonatal morbidities. CONCLUSION: Oropharyngeal colostrum administration is safe in preterm neonates and improves their immunologic profile, showing a potential role as an immunomodulatory agent.

Characterization of Regulatory T Cells in Preterm and Term Infants.

Our study aimed to study regulatory T cells (Tregs) and their expression of CD45RA, HLA-DR, and CD39 in preterm and full-term infants. In an observational study, we used a three-color flow cytometry for determination of Tregs and their expression of CD45RA, HLA-DR, and CD39 in preterm and full-term infants. The percentages of CD4+CD25+highFoxp3+, CD39+ Tregs, HLA-DR+ Tregs and the expression of Foxp3+ in CD4+CD25+highFoxp3 Tregs cells were significantly lower in neonates when compared to healthy adult controls. The levels of naïve resting Tregs (CD45RA+Tregs) were significantly higher in neonates than controls. The percentages of CD4+CD25+highFoxp3+Tregs, total CD4+CD25+ and CD4+CD25+high were significantly higher in preterm infants when compared to the full-term group. Moreover, CD45RA+Tregs were significantly higher in preterm than in term infants. We found significant inverse correlations between the gestational age and the levels of both Tregs (r = - 0.395, p = 0.017) and CD45RA+Tregs (r = - 0.422, p = 0.010). Relative to full-term, the frequencies, and phenotypes of Tregs were affected by prematurity. A larger longitudinal study with a sufficient number of newborns is needed to investigate the Treg pool of term and preterm infants thoroughly and to explore the association between the Treg pool and clinical variables.

[Research advances in immune tolerance of allogeneic cell transplantation in preterm infants].

Preterm infants are a special group, and related severe neurological, respiratory, and digestive disorders have high disability/fatality rates. Allogeneic cell transplantation may be an effective method for the prevention and treatment of these diseases. At present, animal studies have been conducted for allogeneic cell transplantation in the treatment of hypoxic-ischemic encephalopathy, bronchopulmonary dysplasia, and necrotizing enterocolitis. The main difficulty of this technique is graft-versus-host reaction (GVHR), and successful induction of immune tolerance needs to be achieved in order to solve this problem. This article reviews the research advances in immune tolerance of allogeneic cell transplantation in preterm infants.

Digested Early Preterm Human Milk Suppresses Tumor Necrosis Factor-induced Inflammation and Cytotoxicity in Intestinal Epithelial Cells.

OBJECTIVES: The aim of this study was to determine the effect of digested whole human milk (HM; first sample available after birth from mothers of premature infants) on inflammation, oxidative stress, and cytotoxicity in Caco-2 human intestinal epithelial cells stimulated with lipopolysaccharides or tumor necrosis factor (TNF) to mimic the potential in vivo insults facing the premature infant's gastrointestinal tract. METHODS: Fully differentiated Caco-2 cells were exposed to digested HM (n = 10; samples from 10 different individuals) before stimulation with lipopolysaccharides, TNF, or no stimulation overnight. Inflammation was determined by production of interleukin-8, oxidative stress by levels of F2-isoprostane, and cytotoxicity by released lactate dehydrogenase. RESULTS: HM significantly suppressed interleukin-8 production and cytotoxicity in TNF-stimulated cells, while also suppressing cell death under baseline conditions. Individual HM samples differed widely in their ability to modulate cellular responses. CONCLUSIONS: Results from this study provide evidence that digested HM can reduce both an exaggerated inflammatory response and intestinal damage that contribute to the pathogenesis of necrotizing enterocolitis.