Low neonatal Toll-like receptor 4-mediated interleukin-10 production is associated with subsequent atopic dermatitis.

BACKGROUND: Atopic dermatitis (AD) and respiratory syncytial virus lower respiratory tract infection (RSV LRTI) are common diseases during early life. Impaired Th1-cell polarizing Toll-like receptor (TLR) responses play an important role in the pathogenesis of both diseases. Neonatal TLR-mediated production of Th1-type cytokines is decreased at birth, but rapidly increases during the first month of life. OBJECTIVE: To determine whether decreased TLR-mediated production of Th1-polarizing cytokines, at the age of 1 month is associated with subsequent AD or RSV LRTI. METHODS: A prospective healthy birth cohort study was performed. Whole blood concentrations of innate immune cells and TLR-mediated cytokine responses were measured at the age of 1 month in 291 neonates. AD was determined by a physician questionnaire at the age of 1 year and RSV LRTI was defined as parent-reported respiratory symptoms and presence of RSV RNA in a nose-throat specimen. RESULTS: Of participating neonates, 45 (15%) developed AD and 41 (14%) developed RSV LRTI. Risks of AD and RSV LRTI were not associated (χ(2) , P = 1.00). AD was associated with decreased concentrations of basophils (7.6 vs. 14.0 × 10(6) /mL, P = 0.002) and plasmacytoid dendritic cells (17.0 vs. 20.5 × 10(6) /mL, P = 0.04), increased concentrations of NK-cells (79.7 vs. 45.1 × 10(6) /mL, P = 0.03), and twofold lower TLR4-mediated IL-10 production (P = 0.001). In contrast, RSV LRTI was associated neither with neonatal concentrations of innate immune cells, nor with TLR-mediated TNF-α, IL-12p70, IL-10 or IFN-α production. CONCLUSIONS AND CLINICAL RELEVANCE: Atopic dermatitis, but not RSV LRTI, is associated with distinct pre-symptomatic differences in the innate immune system. We hypothesize that decreased neonatal IL-10-mediated immune regulation during early life might play a causal role in the initiation of AD.

Breastfeeding modulates neonatal innate immune responses: a prospective birth cohort study.

BACKGROUND: Neonatal Toll-like receptor (TLR) responses are biased toward Th2-polarizing responses at birth and rapidly mature toward more balanced responses during the first month of life. Postnatal TLR maturation may be guided by environmental exposure. AIMS: To determine the environmental determinants of neonatal TLR function. MATERIALS AND METHODS: A prospective birth cohort study was performed in 291 healthy term neonates. Mode of delivery, breastfeeding, birth month, siblings, pets and parental smoking were analyzed in relation to neonatal innate immune parameters at the age of 1 month. Whole blood concentrations of innate immune cells were measured by flow cytometry. In vitro TLR-mediated cytokine production was determined by ELISA. RESULTS: Breastfeeding was the major determinant of neonatal innate immunity, associated with 5 (31%) of neonatal innate immune parameters, of which the association with TLR7-mediated IL-10 production was most significant (76 pg/ml in breastfed neonates vs. 293 pg/ml in formula-fed neonates, p = 0.001). Of innate immune variables, TLR3-mediated IL-12p70 production was highly associated with environmental exposures (pets, breastfeeding and mode of delivery), whereas TLR9-mediated cytokine responses were not associated with any environmental factor. CONCLUSION: Neonatal innate immune responses are differentially modulated by environmental exposure in the first month of life. The protective effect of breastfeeding against subsequent infections and atopy might be explained by its innate immune modulatory effects in the first month of life.

Relationship between parental lung function and their children's lung function early in life.

This study investigated the relationship between parental lung function and their children's lung function measured early in life. Infants were participants in the Wheezing Illnesses Study Leidsche Rijn (WHISTLER). Lung function was measured before the age of 2 months using the single occlusion technique. Parental data on lung function (spirometry), medical history and environmental factors were obtained from the linked database of the Utrecht Health Project. Parental data on pulmonary function and covariates were available in 546 infants. Univariate linear regression analysis demonstrated a significant positive relationship between the infant's respiratory compliance and parental forced expiratory flow at 25-75% of forced vital capacity (FEF(25-75%))(,) forced expiratory volume in 1 s (FEV(1)) and forced vital capacity. A significant negative relationship was found between the infant's respiratory resistance and parental FEF(25-75%)and FEV(1). No significant relationship was found between the infant's respiratory time constant and parental lung function. Adjusting for body size partially reduced the significance of the observed relationship; adjusting for shared environmental factors did not change the observed results. Parental lung function levels are predictors of the respiratory mechanics of their newborn infants, which can only partially be explained by familial aggregation of body size. This suggests genetic mechanisms in familial aggregation of lung function, which are already detectable early in life.

Disease severity and viral load are correlated in infants with primary respiratory syncytial virus infection in the community.

Respiratory syncytial virus (RSV) is a major cause of respiratory tract infections in infants, with remarkable variability in disease severity. Factors determining severity of disease in previously healthy infants are still unclear. It was hypothesized that disease severity is correlated with viral load in primary RSV infection. Infants of a healthy birth cohort were included at signs of their first respiratory tract infection. Nasopharyngeal aspirate was obtained within 48-96 hr and disease severity was assessed with a previously published severity scoring model. PCR was applied to test the aspirates in a semi-quantitative way for the presence of 10 respiratory pathogens. In case of multiple infection, the pathogen with the highest load was defined as the primary pathogen. The correlation between disease severity and viral load was analyzed. A total of 82 infants were included over a period of 2 years. Median age at first respiratory tract infection was 3 months. Pathogens were detected in 77 (94%) infants; more than one pathogen was detected in 35 (43%) infants. RSV was present in aspirates of 30 infants; in 16 aspirates RSV was the primary pathogen. A negative correlation between RSV CT-value and disease severity was found in all RSV cases (rho = -0.52, P = 0.003) and in cases with RSV as the primary pathogen (rho = -0.54, P = 0.03). In conclusion, this is the first report on viral loads in previously healthy infants with RSV infection in the community. Disease severity correlated positively with viral load during primary RSV infection.

Detection of multiple respiratory pathogens during primary respiratory infection: nasal swab versus nasopharyngeal aspirate using real-time polymerase chain reaction.

In this study, we present the multiple detection of respiratory viruses in infants during primary respiratory illness, investigate the sensitivity of nasal swabs and nasopharyngeal aspirates, and assess whether patient characteristics and viral load played a role in the sensitivity. Healthy infants were included at signs of first respiratory tract infection. Paired nasopharyngeal aspirates and nasal swabs were collected. Real-time polymerase chain reaction (PCR) was carried out for 11 respiratory pathogens. Paired nasopharyngeal aspirates and nasal swabs were collected in 98 infants. Rhinovirus (n = 67) and respiratory syncytial virus (n = 39) were the most frequently detected. Co-infection occurred in 48% (n = 45) of the infants. The sensitivity of the nasal swab was lower than the nasopharyngeal aspirate, in particular, for respiratory syncytial virus (51% vs. 100%) and rhinovirus (75% vs. 97%). The sensitivity of the nasal swab was strongly determined by the cycle threshold (CT) value (p < 0.001). The sensitivity of the swab for respiratory syncytial virus, but not rhinovirus, was 100% in children with severe symptoms (score >or=11). It is concluded that, for community-based studies and surveillance purposes, the nasal swab can be used, though the sensitivity is lower than the aspirate, in particular, for the detection of mild cases of respiratory syncytial virus (RSV) infection.

Skewed pattern of Toll-like receptor 4-mediated cytokine production in human neonatal blood: low LPS-induced IL-12p70 and high IL-10 persist throughout the first month of life.

Newborns are highly susceptible to infectious diseases, which may be due to impaired immune responses. This study aims to characterize the ontogeny of neonatal TLR-based innate immunity during the first month of life. Cellularity and Toll-like receptor (TLR) agonist-induced cytokine production were compared between cord blood obtained from healthy neonates born after uncomplicated gestation and delivery (n=18), neonatal venous blood obtained at the age of one month (n=96), and adult venous blood (n=17). Cord blood TLR agonist-induced production of the Th1-polarizing cytokines IL-12p70 and IFN-alpha was generally impaired, but for TLR3, 7 and 9 agonists, rapidly increased to adult levels during the first month of life. In contrast, TLR4 demonstrated a slower maturation, with low LPS-induced IL-12p70 production and high IL-10 production up until the age of one month. Polarization in neonatal cytokine responses to LPS could contribute to neonatal susceptibility to severe bacterial infection.

Gene expression in CD4+ T-cells reflects heterogeneity in infant wheezing phenotypes.

Although a marked increase in the reporting of wheezing symptoms since the mid-1970s has been described, the underlying immunopathology of the different wheezing phenotypes has not been clarified. Since differences in gene expression might be involved, the objective of the present study was to identify gene expression profiles in CD4+ T-cells from two distinct infant wheezing phenotypes. The gene expression profiles of peripheral CD4+ T-cells were compared by means of microarray analysis of six transient wheezers, six persistent wheezers and seven healthy controls. The differentially expressed genes were subsequently validated by RT-PCR. The differential gene expression profiles reflected common immunological pathways involved in apoptosis or proliferation of T-cells. Furthermore, both wheezing phenotypes showed decreased expression of the complement component 5 receptor 1 gene, a gene involved in the regulation of bronchial responsiveness. Moreover, differences in gene expression profiles were found in genes involved in the immune response against respiratory syncytial virus, such as those encoding signal transducer and activator of transcription 1 and an inflammatory mediator showing enhanced production in asthma (prostaglandin E(2) receptor 2). The present findings suggest that clinical symptoms of wheeze are reflected in common immunological pathways, whereas differences between wheezing phenotypes are, in part, reflected in distinct gene expression profiles.

Participation in daily life of children with asthma.

Asthma can have a negative effect on psychological and social well-being in childhood. Sports participation, school attendance, and quality of life are important issues for children with asthma and their parents. However, a structural evaluation of these factors is not always incorporated in the routine medical approach of children with asthma. Moreover, goals in asthma treatment, such as minimal symptoms and normal activity levels, are achieved in a minority of children. This review describes determinants that are important for the well-being of children with asthma and their parents. Besides the control of symptoms, factors such as sports participation, socializing in peer groups, school attendance, and quality of life must be considered. These issues are relevant when evaluating the management of children and adolescents with asthma. A multidisciplinary evaluation by a pediatrician, school nurse, gym teacher, and psychologist might contribute to an important decrease in the impact of asthma on daily life.

[The basic biomedical subjects are of undiminished importance in the training of medical doctors]. / De biomedische basisvakken zijn onverminderd van belang voor de artsopleiding.

The contemporary physician is not merely a professional who is trained in the recognition of clinical syndromes and the application of evidence-based medicine. A good understanding of the basic biomedical sciences is necessary to comprehend what is wrong with a patient and what form of treatment is the most appropriate, especially if a disease manifests itself in an unfamiliar way.

Antibody neutralization of vascular endothelial growth factor (VEGF) fails to attenuate vascular permeability and brain edema in experimental pneumococcal meningitis.

To determine the contribution of vascular endothelial growth factor (VEGF) to cerebral edema formation in bacterial meningitis, we used a VEGF neutralizing antibody to block VEGF in rabbits, following induction of meningitis by intracisternal inoculation with 10(9) heat-killed pneumococci. At 8 h, cerebrospinal fluid (CSF) VEGF was significantly elevated in infected untreated animals, and correlated with CSF white blood cell (WBC) count (r=0.56, P=0.004), and brain water content (r=0.42, P=0.04). Blocking of VEGF did not attenuate brain edema, blood-brain barrier disruption, or CSF pleocytosis. The functional role of VEGF in the pathophysiology of BM remains elusive.

A difference in perception of quality of life in chronically ill children was found between parents and pediatricians.

BACKGROUND AND OBJECTIVES: Quality of life measurements can help to estimate the well-being of chronically ill patients, and disclose discrepancies in perception between physicians and patients that might otherwise interfere with the effectiveness of treatment. The objective was to investigate the differences in perception of quality of life between parents of chronically ill children and pediatricians. METHODS: A cross-sectional study was conducted in four tertiary pediatric care centers in The Netherlands. The Health Utilities Index mark 3 (HUI3) was used by 37 pediatricians and 279 parents of patients (children aged 1 to 17 years) with cystic fibrosis admitted either in daycare or for a pneumonia, or patients with newly diagnosed acute lymphoblastic leukemia, juvenile idiopathic arthritis, or asthma. RESULTS: Differences in perception of quality of life between parents and pediatricians appeared to be dependent of the disease. In patients with acute lymphoblastic leukemia (OR 7.4; [95% CI 2.88-18.97], juvenile idiopathic arthritis (4.7; [95% CI 2.00-11.22]), and asthma (2.3; [95% CI 1.13-4.69]) a difference in perception was more likely to occur than in patients with cystic fibrosis admitted in daycare. CONCLUSION: At the onset of a chronic disease, the parents of pediatric patients may be misunderstood by health care professionals, especially in subjective attributes. Assessment of quality of life may contribute to better understanding between pediatricians and parents, and thus may even enhance compliance and treatment effects.

Quality of life: patients and doctors don't always agree: a meta-analysis.

OBJECTIVE: In addition to traditional clinical markers, quality-of-life assessment can be helpful to estimate the well-being of patients. Discrepancies in perception of well-being between physicians and patients may interfere with the effectiveness of treatment. A systematic review and meta-analysis were performed to explore the (dis-)agreement in quality-of-life assessments between patients and physicians. STUDY DESIGN AND SETTING: Data on the proportion agreement of paired observations were collected from Medline, Embase, Psychlit, and Social Abstracts. RESULTS: Of the 1,316 articles found, six met the selection criteria, four studied the proportion agreement between children and physicians, and all six the proportion agreement between parents and physicians. None examined the magnitude of over- or underestimation by physicians. The agreement was lower in the more subjective domains (0.54-0.77) in comparison to the more objective domains (0.79-0.94). CONCLUSION: Quality-of-life assessment should be integrated in clinical practice. During long-term treatment the perception of the patients' well-being by physicians and patients themselves can easily diverge from each other, resulting in misunderstandings about the treatment and its usefulness in relation to perceived quality of life, and may even become the base for noncompliance.

[Double blind placebo controlled cow's milk provocation for the diagnosis of cow's milk allergy in infants and children]. / Dubbelblinde placebogecontroleerde koemelkprovocatie voor de diagnostiek van koemelkallergie bij zuigelingen en kinderen.

OBJECTIVE: To test a protocol for a double-blind placebo-controlled cow's milk provocation for the diagnosis of acute allergic reactions to milk in an outpatient setting. DESIGN: Prospective, descriptive. METHOD: During the period from June 1, 1999 to February 28, 2001 the protocol was tested on all infants and children who were referred to the Paediatric outpatient clinic of the University Medical Centre on Utrecht with symptoms indicative of cow's milk allergy. The protocol comprised of a phased administration of two test meals, one with a true feed and one with placebo, during the course of one day. In case of allergic symptoms the test was discontinued and the code was broken. A diagnosis of 'cow's milk allergy' was made if the symptoms appeared during the provocation with true feeding. RESULTS: The test group (n = 154) consisted of 85 boys and 69 girls with ages ranging from 0.25 to 14 years (median 1.5). Acute type reactions to cow's milk occurred in 21 of the children who underwent the provocation. These reactions mainly consisted of cutaneous symptoms (erythema and urticaria). In none of these cases the symptoms were severe enough to require a prolonged stay in the hospital. There were no reactions on placebo meals nor acute reactions during the reintroduction of milk at home. CONCLUSION: It is possible to perform double-blind placebo-controlled provocations routinely in the diagnostic work-up of children with a suspicion of cow's milk allergy.

Transmission of respiratory syncytial virus at the paediatric intensive-care unit: a prospective study using real-time PCR.

Transmission of respiratory syncytial virus (RSV) from children with lower respiratory tract infection (LRTI) at a paediatric intensive-care unit (PICU) was examined using a highly sensitive real-time PCR. Twenty-four children with RSV LRTI were admitted during the study period (total days of potential transmission: 239). Forty-eight RSV-negative patients were followed up for RSV acquisition every 5 days (total days of exposure: 683). No single RSV transmission was documented with this highly sensitive diagnostic method. Therefore, routine infection control measures of LRTI patients seem to be adequate to prevent RSV transmission at the PICU.

Quality of life in chronic illness: children, parents and paediatricians have different, but stable perceptions.

AIM: Quality of life assessments can be helpful to estimate the well-being of chronically ill children. The aim of this study was to investigate the differences in perception of health-related quality of life (HRQoL) among children, parents and paediatricians at the time of diagnosis and after initial treatment in four chronic diseases. METHODS: HRQoL was assessed with the Health Utilities Index mark 3 (HUI3). The HUI3 consists of eight attributes (vision, hearing, speech, ambulation, dexterity, emotion, cognition and pain). RESULTS: Nineteen paediatricians and 60 patients (aged 10-17 years) and their parents with newly diagnosed acute lymphoblastic leukaemia, juvenile idiopathic arthritis, asthma or with cystic fibrosis admitted for pneumonia participated in the study. Health and well-being perceptions were clearly different among paediatricians, parents and patients, both at diagnosis and after initial treatment. Perception differences were more prominent in the subjective attributes, emotion and pain. The agreement for these attributes was 23% and 5%, respectively. Paediatricians assessed the patients to have less pain than the patients and parents did. The reverse was true for the attribute emotion. At follow-up, the agreement was higher for the attributes ambulation and pain. CONCLUSION: At the onset of a chronic disease and after initial treatment, paediatricians, parents and children have different perceptions of the child's quality of life, particularly as to the subjective attributes pain and emotion. In view of these differences in perception among patients, their caregivers and paediatricians, this study suggests that whenever possible, multi-respondent assessment of HRQoL should be considered.

The impact of laboratory characteristics on molecular detection of respiratory syncytial virus in a European multicentre quality control study.

The performance of nucleic acid amplification techniques for detecting respiratory syncytial virus (RSV) was evaluated in 25 laboratories across Europe by an external quality assessment study. In addition, factors related to the diagnostic performance of laboratories were explored. The results of this quality control study show that the performance of laboratories for RSV diagnosis in Europe is good, with an overall correct score of 88%. The type of assay (nested or real-time PCR vs. commercial tests) was identified as a significant factor (OR 8.39; 95% CI 1.91-36.78) in predicting a correct result.

Adherence to follow-up recommendations in asthma.

A cross-sectional study showed that 130 out of 1758 (8%) primary school children without a previous asthma diagnosis had undiagnosed asthma. Thirty-eight per cent of their parents refused to visit a general practitioner for this disorder. Factors associated with the refusal were high maternal education, mild symptoms and absence of airway reversibility.

Pseudomonas aeruginosa diversity in distinct paediatric patient groups.

Pseudomonas aeruginosa is a pathogen that often infects patients who are either immunocompromised or have local defects in host defences. It is known that cystic fibrosis (CF) patients are sometimes infected with certain clonal isolates. It is not clear whether these clonal isolates also infect non-CF patients and whether clonality of isolates occurs in other patient groups. The aim of this study was to investigate P. aeruginosa diversity and the occurrence of clones within five distinct paediatric patient groups susceptible to P. aeruginosa infection. P. aeruginosa isolates were cultured from 157 patients (CF first infection (CF-1 group) (29); CF chronic infection (CF-chronic group) (27); urinary tract infection (34); chronic suppurative otitis media (43); and intensive-care hospitalization/immunodeficiency (24)). All 202 phenotypically different isolates were tested for antimicrobial resistance and further typed by pulsed-field gel electrophoresis. Simpson's diversity index was calculated for the five groups. CF-chronic patients carried the highest number of distinct P. aeruginosa phenotypes and genotypes per culture. Isolates from the CF-chronic group were significantly less diverse than those from the other groups. A group of clonal isolates was observed among patients from the CF-chronic and CF-1 groups. These or different clonal isolates were not encountered among the three other patient groups. No characteristic resistance pattern could be identified among isolates from the distinct patient groups and among the clonal isolates. In conclusion, isolates of the CF-chronic group were less diverse than those in the other patient groups with P. aeruginosa infection; clonal isolates were not encountered in non-CF patients. Transmission of clonal CF isolates to other patient groups was not observed.

Poor perception of dyspnoea in children with undiagnosed asthma.

The aim of the present study was to establish the differences in dyspnoea perception between children with undiagnosed and diagnosed asthma. A cross-sectional community-based study was performed, which included a parental questionnaire on the child's respiratory health and testing of airway reversibility and bronchial hyperresponsiveness (BHR). "Diagnosed asthma" was defined by a physician's diagnosis of asthma. "Undiagnosed asthma" was defined by the presence of asthma symptoms combined with either airway reversibility or BHR without a physician's diagnosis of asthma. Only children with a positive BHR test were selected for further analysis. Perception of dyspnoea was assessed using the Borg scale and the visual analogue scale (VAS), plotted against the percentage fall in forced expiratory volume in one second and expressed as the slope of the regression line. Of the initial 1,758 participating children, 70 had undiagnosed asthma and 38 had diagnosed asthma. The Borg and VAS slopes in children with undiagnosed asthma were less steep than those of children with diagnosed asthma (Borg: 0.07 and 0.14, respectively; VAS: 0.06 and 0.11, respectively). Among children with bronchial hyperresponsiveness, those without a parent's report of physician's diagnosis of asthma had a worse perception of dyspnoea than children with diagnosed asthma.

Selection of probiotic bacteria for prevention of allergic diseases: immunomodulation of neonatal dendritic cells.

Modification of intestinal microbiota early in life by administration of probiotic bacteria may be a potential approach to prevent allergic disease. To select probiotic bacteria for in vivo purposes, we investigated the capacity of probiotic bacteria to interact with neonatal dendritic cells (DC) and studied the ensuing T cell polarizing effect. Immature DC were generated from cord blood-derived monocytes and maturation was induced by maturation factors (MF), lipopolysaccharide (LPS) plus MF and Bifidobacterium bifidum, B. infantis, Lactobacillus salivarius, Lactococcus lactis alone or combined with MF. After 12 days of co-culture with DC and Staphylococcus aureus enterotoxin B (SEB) as antigenic stimulus, cytokine production by autologous T cells was determined by intracellular cytokine staining. Additionally, cells were stimulated with CD3 and CD28 monoclonal antibodies and cytokines were measured in supernatants by multiplex assay. The probiotic strains induced partial maturation of DC. Full maturation of DC was induced for all strains tested when MF was added. The percentage of interleukin (IL)-4 producing T cells was lower in T cell cultures stimulated with B. bifidum matured DC compared to MF and LPS matured DC, which coincided with a higher percentage of interferon (IFN)-gamma-producing T cells. Furthermore, T cells stimulated by B. bifidum matured DC produced significantly more IL-10 compared to MF matured DC. Selected species of the Bifidobacterium genus prime in vitro cultured neonatal DC to polarize T cell responses and may therefore be candidates to use in primary prevention of allergic diseases.