Cytokine production by newborns: influence of sex and season of birth.

BACKGROUND: Immune signatures at birth could be associated with clinical outcomes and will improve our understanding of immunity prenatal programming. METHODS: Data come from 235 newborns from the cohort study NELA. Production of cytokines was determined using Luminex technology. Associations between cytokine concentrations with sex and season of birth were examined by multivariate regression models. RESULTS: Umbilical cord blood cells produced high levels of inflammatory cytokines, moderate levels of Th1/Th2/Tr-related cytokines, and low levels of Th17 cytokines. Compared to females, male newborn cells secreted higher levels of Th2 (peptidoglycan-stimulated IL-13, odds ratio [OR] = 2.26; 95% CI 1.18, 4.31, p value = 0.013) and Th17 (polyinosinic:polycytidylic acid-stimulated IL-23, OR = 1.82, 95% CI 1.01, 3.27, p value = 0.046) and lower levels of Th1 (olive-stimulated IL-2, OR = 0.56, 95% CI 0.31, 0.99, p value = 0.047) cytokines. Also, children born during warm seasons showed decreased innate cytokine response to peptidoglycan (IL-6, OR = 0.28, 95% CI 0.15, 0.52, p value < 0.001) compared to those born in cold seasons; meanwhile, adaptive immunity cytokines were more frequently secreted by children born during warm seasons in response to allergen extracts (IL-10, OR = 2.11, 95% CI 1.12, 3.96, p value = 0.020; IL-17F, OR = 3.31, 95% CI 1.83, 5.99, p value < 0.001). CONCLUSION: Newborns showed specific cytokines signatures influenced by sex and season of birth. IMPACT: There is a limited number of population-based studies on the immune status at birth and the influence of prenatal and perinatal factors on it. Characterization of cytokine signatures at birth related to the prenatal environment could improve our understanding of immunity prenatal programming. Newborns exhibit specific unstimulated and stimulated cytokine signatures influenced by sex and season of birth. Unstimulated and stimulated cytokine signatures in newborns may be associated with the development of related clinical outcomes later in life.

Percent body fat, skinfold thickness or body mass index for defining obesity or overweight, as a risk factor for asthma in schoolchildren: which one to use in epidemiological studies?

None of the epidemiological studies indicating that obesity is a risk factor for asthma in schoolchildren have used the percent body fat (PBF) to define obesity. The present study compares the definition of obesity using body mass index (BMI), PBF and the raw sum of the thickness of four skinfolds (SFT) to evaluate this condition as a risk factor for asthma. All classes of children of the target ages of 6-8 years of all schools in four municipalities of Murcia (Spain) were surveyed. Participation rate was 70.2% and the number of children included in the study was 931. Height, weight and SFT (biceps, triceps, subscapular and suprailiac) were measured according to standard procedures. Current active asthma was defined from several questions of the International Study of Asthma and Allergies in Childhood questionnaire. Obesity was defined using two standard cut-off points for BMI and PBF, and the 85th percentile for BMI, PBF and SFT. The highest quartile of each type of measurement was also compared with the lowest. A multiple logistic regression analysis was made for the various obesity definitions, adjusting for age, asthma in the mother and father and gender. The adjusted odds ratios of having asthma among obese children were different for boys and girls and varied across the different obesity definitions. For the standard cut-off points of BMI they were 1.19 [95% confidence interval (CI) 0.41-3.43] for girls and 2.00 (95% CI 0.97-4.10) for boys; however, for PBF (boys 25%, girls 30%) the corresponding figures were 1.54 (95% CI 0.63-3.73) and 1.20 (95% CI 0.66-2.21). BMI, PBF and SFT showed more consistency between each other when using the other cut-off points. BMI, PBF (except standard cut-off points) and SFT produce relatively comparable results when analysing the interaction between obesity and asthma.

Phadiatop compared to skin-prick test as a tool for diagnosing atopy in epidemiological studies in schoolchildren.

The validity of the Phadiatop test as compared to the skin-prick test (SPT) for diagnosing atopy in the epidemiological field has not been studied in schoolchildren. The aim of the present study was to evaluate its validity for classifying schoolchildren 9-12 yr old into atopics and non-atopics. A total of 621 children whose parents authorized both a SPT and a blood extraction from all children participating in the phase II of the International Study of Allergies in Children (ISAAC) in Cartagena (Spain) were included in the analysis. A positive SPT was that with at least a wheal having a maximum diameter of 3 mm, once the negative value had been subtracted. Phadiatop was performed according to the manufacturer instructions. Diagnostic tests using SPT as the gold standard were calculated for the whole group of children and also for those with asthma or rhinoconjunctivitis and for children without any of them. The results of the tests were: sensitivity 85.0% (95% CI 82.2-87.8%), specificity 85.5% (95%CI 82.7-88.3%), positive predictive value 72.7% (95%CI 69.0-76.1%), negative predictive value 92.7% (95%CI 90.6-94.7%) and accuracy 85.3% (95%CI 82.3-88.0%). The results improved among the symptomatic groups. Phadiatop can be used as a valid alternative to SPT in the epidemiological setting to diagnose atopy.

Antibody levels to Bordetella pertussis in 10-yr-old children with atopy and atopic asthma.

Suboptimal immune responses to vaccination have been suggested among atopic infants. The aim of this study was to assess the influence of atopy and atopic asthma on the humoral response to Bordetella pertussis vaccination. Immunoglobulin (Ig)G and IgA specific antibodies were measured by enzyme linked-immunosorbent assay in 102, 10-yr-old atopic children (66 of them also being asthmatics) and compared with 76 non-atopic and 53 non-atopic non-asthmatic controls of similar age. The levels of antibodies and the percentage of positives to B. pertussis were comparable in all groups. Children with a very high total serum immunoglobulin (Ig)E (Percentile (Pct) > 90th) showed higher (p = 0.01) IgG pertussis antibodies than children with very low serum IgE (Pct < 10th). In conclusion, we found normal pertussis antibody levels in atopic and in atopic asthmatic children in late childhood, thus overriding any possible suboptimal response during infancy.