Neonates colonized with pathogenic bacteria in the airways have a low-grade systemic inflammation.

BACKGROUND AND OBJECTIVES: The development of childhood asthma is associated with neonatal colonization with pathogenic bacteria in hypopharynx. Furthermore, established asthma is associated with systemic low-grade inflammation. We here report on the association between neonatal colonization with pathogenic bacteria in hypopharynx and the development of systemic low-grade inflammation. METHODS: Bacterial colonization of the hypopharynx with Moraxella catharralis, Haemophilus influenzae, and/or Streptococcus pneumoniae was assessed in asymptomatic children from the Copenhagen Prospective Studies on Asthma in Childhood2000 (COPSAC2000 ) cohort at age 1 month by culturing technique (N = 238) and by quantitative polymerase chain reaction (qPCR) technique (N = 249) and in the COPSAC2010 cohort by culturing at age 1 month (N = 622) and again at age 3 months (N = 613). Systemic low-grade inflammation was determined in both cohorts at age 6 months by measuring plasma levels of high-sensitivity C-reactive protein (hs-CRP), tumor necrosis factor-α (TNF-α), and interleukin-6 (lL-6). RESULTS: In both cohorts, bacterial colonization was associated with increased levels of hs-CRP: COPSAC2000 , 1 month culturing (geometric mean ratio of colonized/noncolonized [95% CI]), 1.39 [0.97-2.01], P = .08; 1 month qPCR, 1.55 [1.14-2.10], P < .01; COPSAC2010 , 1 month, 1.52 [1.23-1.87], P < .01; and 3 month, 1.57 [1.30-1.90], P < .01. A multiparametric principal component analysis incorporating hs-CRP, TNF-α, and IL-6 confirmed a systemic inflammatory profile in children colonized with M. catharralis, H. influenzae. and/or S. pneumoniae in the hypopharynx compared to noncolonized children (P-values < .05). CONCLUSION: The composition of the upper airway microbiome in early life may cause systemic low-grade inflammation.

Genetic associations with viral respiratory illnesses and asthma control in children.

BACKGROUND: Viral respiratory infections can cause acute wheezing illnesses in children and exacerbations of asthma. OBJECTIVE: We sought to identify variation in genes with known antiviral and pro-inflammatory functions to identify specific associations with more severe viral respiratory illnesses and the risk of virus-induced exacerbations during the peak fall season. METHODS: The associations between genetic variation at 326 SNPs in 63 candidate genes and 10 phenotypes related to viral respiratory infection and asthma control were examined in 226 children enrolled in the RhinoGen study. Replication of asthma control phenotypes was performed in 2128 children in the Copenhagen Prospective Study on Asthma in Childhood (COPSAC). Significant associations in RhinoGen were further validated using virus-induced wheezing illness and asthma phenotypes in an independent sample of 122 children enrolled in the Childhood Origins of Asthma (COAST) birth cohort study. RESULTS: A significant excess of P values smaller than 0.05 was observed in the analysis of the 10 RhinoGen phenotypes. Polymorphisms in 12 genes were significantly associated with variation in the four phenotypes showing a significant enrichment of small P values. Six of those genes (STAT4, JAK2, MX1, VDR, DDX58, and EIF2AK2) also showed significant associations with asthma exacerbations in the COPSAC study or with asthma or virus-induced wheezing phenotypes in the COAST study. CONCLUSIONS: We identified genetic factors contributing to individual differences in childhood viral respiratory illnesses and virus-induced exacerbations of asthma. Defining mechanisms of these associations may provide insight into the pathogenesis of viral respiratory infections and virus-induced exacerbations of asthma.

Disagreement between skin prick test and specific IgE in young children.

BACKGROUND: Skin prick test (SPT) and measurement of serum-specific IgE (sIgE) level are important tools for the clinician to diagnose allergic sensitization. However, little is known about the agreement between the two methods in young children. METHODS: SPT and sIgE levels were assessed simultaneously for 16 common inhalant and food allergens at age ½, 1½, 4, and 6 years in 389 children from the Copenhagen Prospective Study on Asthma in Childhood2000 (COPSAC2000 ) at-risk birth cohort. Agreement between the two methods for diagnosing inhalant and food allergic sensitization at the four age points was analyzed using kappa statistics. RESULTS: The prevalence of inhalant allergen sensitization increased during childhood diagnosed by both sIgE levels (0.6% to 4.2% to 18.1% to 24.8%, P < 0.0001) and SPT results (1.5% to 3.8% to 8.4% to 15.4%, P < 0.0001). In contrast, the prevalence of food sensitization increased during childhood when diagnosed from sIgE (7.8% to 12.1% to 15.0% to 18.9%, P < 0.0001), but decreased when diagnosed from SPT (5.3% to 5.1% to 3.7% to 3.0%, P = 0.05). Overall, the agreement between SPT and sIgE levels was poor to moderate (all κ-coefficients ≤ 0.60) and decreased from moderate to slight for food allergens by increasing age (κ-coefficients: 0.46 to 0.31 to 0.16 to 0.14). CONCLUSION: There is a substantial disagreement between SPT and sIgE for diagnosing allergic sensitization in young children, which increases with age for food sensitization. Choice of assessment method therefore has major impact on results with wide implications for both clinical practice and research.

17q21 gene variation is not associated with asthma in adulthood.

BACKGROUND: 17q21 gene variants are the strongest known genetic determinants for childhood asthma and have been reported to interact with environmental tobacco smoke exposure in childhood. It remains unclear whether individuals with 17q21 risk variants have increased risk of asthma or reduced lung function in adulthood. The aim was to examine the association between the 17q21 region and current adult asthma and lung function, and interaction with active smoking. METHODS: We investigated the single nucleotide polymorphism rs7216389 at the 17q21 locus in 3471 adults from the Health2006 cross-sectional study and in 7008 adults from The British 1958 Birth Cohort and examined the association with current asthma, spirometry measures, and related atopic traits. Analyses were performed for interaction with active smoking. RESULTS: We found no association between rs7216389[T] and asthma when meta-analyzed (OR = 1.02 [0.92-1.13], P = 0.81). The risk variant was associated with reduced FEV1 as compared to normal FEV1 (OR = 1.10 [1.01-1.12], P = 0.033) and with allergic sensitization (OR = 1.10 [1.03-1.17], P = 0.003). Individuals with rs7216389 risk variants smoked as frequently as individuals without risk variants, and there was no evidence that smoking modified the association between rs7216389 and asthma. CONCLUSION: Our study suggests that the 17q21 rs7216389 locus variant does not substantially influence asthma risk in adulthood or susceptibility to detrimental effects of active smoking. This contrasts the findings in children and suggests that this locus is associated with a childhood-specific asthma endotype.

Immune-mediated diseases and microbial exposure in early life.

The non-communicable disease pandemic includes immune-mediated diseases such as asthma and allergy, which are likely originating in early life where the immature immune system is prone to alterations caused by the exposome. The timing of exposure seems critical for the developing immune system, and certain exposures may have detrimental effects in the earliest life, but no or even beneficial effects later. The human microbiome and infections are candidates as intermediary in the interaction between the host and the environment. The evidence seems inconsistent as infections as well as particular colonization patterns in neonates drive both short-term and long-term asthma symptoms, while, on the other hand, the composition of the microbiome in early life may protect against asthma and allergy in later life. This apparent contradiction may be explained by a deeper disease heterogeneity than we are currently able to discriminate, and in particular, the indiscriminate lumping together of different diseases into one atopic disease category. Also, the microbiome needs a differentiated understanding, considering balance between microbial groups, diversity and microbial genetic capability. Furthermore, the effects of the microbial exposure may only affect individuals with certain susceptibility genes. Few of the observations have been replicated, and publication bias is likely. Therefore, we are still far from understanding, or having proved, causal effects of the human microbiome. Still, the microbiome-gene interaction is a fascinating paradigm that fosters exiting research and promises a breakthrough in the understanding of the mechanisms driving asthma, allergy and eczema, and potentially also other immune-mediated non-communicable diseases.

Antibiotic use during pregnancy alters the commensal vaginal microbiota.

Antibiotics may induce alterations in the commensal microbiota of the birth canal in pregnant women. Therefore, we studied the effect of antibiotic administration during pregnancy on commensal vaginal bacterial colonization at gestational week 36. Six hundred and sixty-eight pregnant women from the novel unselected Copenhagen Prospective Studies on Asthma in Childhood (COPSAC2010 ) pregnancy cohort participated in this analysis. Detailed information on oral antibiotic prescriptions during pregnancy filled at the pharmacy was obtained and verified prospectively. Vaginal samples were obtained at pregnancy week 36 and cultured for bacteria. Women who received oral antibiotics during any pregnancy trimester had an increased rate of colonization by Staphylococcus species in the vaginal samples as compared with samples obtained from women without any antibiotic treatment during pregnancy (adjusted OR 1.63, 95% CI 1.06-2.52, p 0.028). Oral antibiotic administration in the third trimester were also associated with increased colonization by Staphylococcus species (adjusted OR 1.98, 95% CI 1.04-3.76, p 0.037). These bacteriological changes were associated with urinary tract infection antibiotics. Women treated in the third trimester of pregnancy were more often colonized by Escherichia coli than women without antibiotic treatment in the third trimester (adjusted OR 1.91, 95% CI 1.04-3.52, p 0.038). This change was associated with respiratory tract infection (RTI) antibiotics. We did not observe any significant changes in vaginal Streptococcus agalactiae (group B streptoccocus) or Staphylococcus aureus colonization following antibiotic treatment in pregnancy. Antibiotic administration during pregnancy leads to alterations in the vaginal microbiological ecology prior to birth, with potential morbidity, and long-term effects on the early microbial colonization of the neonate.

Deep phenotyping of the unselected COPSAC2010 birth cohort study.

BACKGROUND: We hypothesize that perinatal exposures, in particular the human microbiome and maternal nutrition during pregnancy, interact with the genetic predisposition to cause an abnormal immune modulation in early life towards a trajectory to chronic inflammatory diseases such as asthma and others. OBJECTIVE: The aim of this study is to explore these interactions by conducting a longitudinal study in an unselected cohort of pregnant women and their offspring with emphasis on deep clinical phenotyping, exposure assessment, and biobanking. Exposure assessments focus on the human microbiome. Nutritional intervention during pregnancy in randomized controlled trials are included in the study to prevent disease and to be able to establish causal relationships. METHODS: Pregnant women from eastern Denmark were invited during 2008-2010 to a novel unselected 'COPSAC2010 ' cohort. The women visited the clinic during pregnancy weeks 24 and 36. Their children were followed at the clinic with deep phenotyping and collection of biological samples at nine regular visits until the age of 3 and at acute symptoms. Randomized controlled trials of high-dose vitamin D and fish oil supplements were conducted during pregnancy, and a trial of azithromycin for acute lung symptoms was conducted in the children with recurrent wheeze. RESULTS: Seven hundred and thirty-eight mothers were recruited from week 24 of gestation, and 700 of their children were included in the birth cohort. The cohort has an over-representation of atopic parents. The participant satisfaction was high and the adherence equally high with 685 children (98%) attending the 1 year clinic visit and 667 children (95%) attending the 2 year clinic visit. CONCLUSIONS: The COPSAC2010 birth cohort study provides longitudinal clinical follow-up with highly specific end-points, exposure assessments, and biobanking. The cohort has a high adherence rate promising strong data to elucidate the interaction between genomics and the exposome in perinatal life leading to lifestyle-related chronic inflammatory disorders such as asthma.

VEGFA variants are associated with pre-school lung function, but not neonatal lung function.

BACKGROUND: Vascular endothelial growth factor (VEGF) is implicated in airway remodelling and asthma development. We studied VEGFA gene variants and plasma levels and the development of lung function, bronchial hyperresponsiveness and asthma in childhood. METHODS: We analysed 13 SNPs in the VEGFA gene in 411 children from the COPSAC2000 high-risk birth cohort. Asthma was diagnosed prospectively, and lung function measurements were obtained at birth and 6 years of age. Plasma VEGF levels were measured at 18 months of age. We used a Bonferroni adjusted significance level. Findings were replicated in the Prevention and Incidence of Asthma and Mite Allergy (PIAMA) birth cohort at age 8. RESULTS: At age six, three SNPs from the same linkage block were associated with FEV1 (rs699947, P = 1.31E-05), independent of asthma, and there were suggestive associations between FEV1/FVC ratio and rs833052 and maximal mid-expiratory flow and rs6900017. Replication in the PIAMA cohort showed borderline association between FEV1 and rs699947 and significant meta-analysis result. SNPs upstream and nearby rs699947 were nominally associated with VEGF plasma levels. VEGF levels were not associated with asthmatic symptoms or lung function measures. CONCLUSIONS AND CLINICAL RELEVANCE: VEGF gene variants are associated with lung function at school age, but not at birth, suggesting a role of VEGF in post-natal lung function development.

Association between whole-blood polyunsaturated fatty acids in pregnant women and early fetal weight.

BACKGROUND/OBJECTIVES: Studies suggest that intake of marine n-3 polyunsaturated fatty acids (n-3 PUFA) in pregnancy have an impact on birth weight, but only few have investigated the effect on early fetal growth. The objective of the study was to investigate the association between levels of PUFA in maternal blood in gestational week 24 and biometric measures and estimated fetal weight in gestational week 20. SUBJECTS/METHODS: In the COPSAC2010 cohort, whole-blood fatty acid composition (a biomarker of PUFA intake) from 583 women in week 24 was analyzed by gas chromatography. Biometric data (head circumference, abdominal circumference and femur length) were collected by ultra sound in week 20 and fetal weight was estimated. Associations between whole-blood PUFA (docosahexaenoic acid (DHA), total n-3 PUFA, n-6/n-3 PUFA, total n-6 PUFA) and fetal weight and biometrics measures were analyzed by multivariable-adjusted linear regression analyses. RESULTS: There was a wide range in maternal blood DHA, which varied from 1.8 to 6.9% depending on socioeconomic status, smoking and body mass index. After adjusting for these variables, no association was observed between any of the assessed PUFA components and the circumference of head or abdomen or fetal weight. However, an inverse association was established between DHA and total n-3 PUFA and femur length (P<0.02). CONCLUSION: Maternal whole-blood PUFA composition, specifically her n-3 PUFA status, in gestational week 24 was not associated with overall early fetal weight gain, but this study indicates that it may decrease the length of femur.

Cord blood Th2-related chemokine CCL22 levels associate with elevated total-IgE during preschool age.

BACKGROUND: Early-life immune deviation is suspected in the inception of atopic disease. OBJECTIVE: To investigate the association between cord blood chemokines and the subsequent development of atopic biomarkers and clinical end-points during the first 6 years of life. METHODS: The Th1-associated chemokines CXCL10 and CXCL11 and the Th2-associated chemokines CCL17 and CCL22 were assessed in cord blood of asymptomatic at-risk newborn children from the Copenhagen Prospective Study on Asthma in Childhood (COPSAC(2000) ) birth cohort and associated with the longitudinal development of biomarkers and clinical end-points of asthma, eczema, and allergic rhinitis during the first 6 years of life. RESULTS: Cord blood CCL22 levels were significantly associated to total-IgE levels measured at four time-points during the first 6 years of life; overall odds ratio, 1.54 [CI, 1.25-1.89; P < 0.0001]. CXCL10 and CXCL11 were not associated with development of any atopic disorders or biomarkers. CONCLUSION AND CLINICAL RELEVANCE: High cord blood levels of the Th2 related chemokine CCL22 were significantly associated with high total- IgE levels during the first 6 years of life, but not with specific sensitization, asthma, eczema or allergic rhinitis. This suggests an inborn skewing of the immune system in healthy newborns developing elevated total- IgE later in life.

Allergic rhinitis is associated with otitis media with effusion: a birth cohort study.

BACKGROUND: Childhood otitis media with effusion is a common disease and a link to allergic diseases has been suggested. OBJECTIVE: To investigate the association between atopic disease and otitis media with effusion diagnosed according to strict objective case definitions by age 6 years. METHODS: We evaluated 291 children in the 6th year of life from the Copenhagen Prospective Studies on Asthma in Childhood (COPSAC) 2000 birth cohort. Otitis media with effusion was diagnosed based on tympanometric and objective evaluation. Asthma, eczema, allergic- and non-allergic rhinitis was diagnosed prospectively by pre-defined algorithms. Nasal mucosal swelling was assessed using acoustic rhinometry and nasal eosinophilia from scrapings. Analyses were performed using logistic regression and adjusted for dog, cat and smoking exposure, paternal atopy, household income, older siblings, gender and number of acute otitis media episodes. RESULTS: Otitis media with effusion was diagnosed in 39% of the cohort and was associated with allergic rhinitis (aOR = 3.36, CI = 1.26-8.96, P = 0.02), but not with nasal mucosal swelling, nasal oeosinophilia, non-allergic rhinitis, asthma or eczema. CONCLUSION: Otitis media with effusion is closely associated with allergic rhinitis presumably caused by allergic inflammation, but not mechanical nasal mucosal swelling. These findings warrant an increased awareness of otitis media with effusion in children with allergic rhinitis.

Determinants of lung function and airway hyperresponsiveness in asthmatic children.

BACKGROUND: Asthma patients exhibit an increased rate of loss of lung function. Determinants to such decline are largely unknown and the modifying effect of steroid therapy is disputed. This cross-sectional study aimed to elucidate factors contributing to such decline and the possible modifying effect of steroid treatment. METHODS: We analyzed determinants of lung function and airway hyperresponsiveness (AHR) in a Scandinavian study of 2390 subjects from 550 families. Families were selected for the presence of two or more asthmatic children as part of a genetic study, Scandinavian Asthma Genetic Study (SAGA). RESULTS: The primary analysis studied the association between the lung function and delay of inhaled corticosteroids (ICS) after asthma diagnosis among asthmatic children and young adults with a history of regular ICS treatment (N=919). FEV(1) percent predicted (FEV(1)% pred) was 0.25% lower per year of delay from diagnosis until treatment (p=0.039). This association was significantly greater in allergy skin prick test negative children. There was no significant influence of gender, age at asthma onset, or smoking. In the secondary analysis of the whole population of 2390 asthmatics and non-asthmatics, FEV(1)% pred was inversely related to having asthmatic siblings (-7.9%; p<0.0001), asthma diagnosis (-2.7%; p=0.0007), smoking (-3.5%; p=0.0027), and positive allergy skin prick test (-0.47% per test; p=0.012), while positively related to being of female gender (1.8%; p=0.0029). Risk of AHR was higher by having asthmatic siblings (OR 2.7; p<0.0001), being of female gender (OR 2.0; p<0.0001), and having asthma (OR 2.0; p<0.0001). CONCLUSIONS: These data suggest that lung function is lower in asthmatics with delayed introduction of ICS therapy, smoking, and positive allergy skin prick test. Lung function is lower and AHR higher in female asthmatics and subjects with asthmatic siblings or established asthma.