Distinction between rhinovirus-induced acute asthma and asthma-augmented influenza infection.

BACKGROUND: Rhinovirus (RV) is an established trigger of asthma attacks, whereas such a link is less consistent for influenza virus (IFV). OBJECTIVE: In the context of precision medicine, we hypothesized that IFV infection may cause a condition essentially different from RV, and we investigated this by evaluating clinical characteristics of RV/IFV-positive and -negative children with respiratory symptoms and/or fever. METHODS: One thousand two hundred and seven children, 6 months to 13 years old, hospitalized for flu-like illness were recruited in this cross-sectional study. Collected information included demographics, medical history, symptoms/physical findings/diagnosis at presentation and treatment. Nasal secretions were PCR-tested for IFV/RV. Associations were evaluated with adjusted logistic regression models. RESULTS: Rhinovirus positivity was associated with an asthma-like presentation, including increased wheeze/effort of breathing/diagnosis of acute asthma, and decreased fever/vomiting. Conversely, IFV+ children presented with less wheeze/effort of breathing/diagnosis of acute asthma, while they were more frequently febrile. In those with previous asthma history, both viruses induced wheeze; however, IFV was uniquely associated with a more generalised and severe presentation including fever, rales, intercostal muscle retractions and lymphadenopathy. These symptoms were not seen in RV+ asthmatics, who had fewer systemic signs and more cough. CONCLUSIONS AND CLINICAL RELEVANCE: In children with respiratory symptoms and/or fever, RV but not IFV is associated with wheeze and an asthma-like presentation. In those with an asthma history, IFV causes more generalised and severe disease that may be better described as "asthma-augmented influenza" rather than an "asthma attack." Differences in the acute conditions caused by these viruses should be considered in the design of epidemiological studies.

Conception via in vitro fertilization and delivery by Caesarean section are associated with paediatric asthma incidence.

BACKGROUND: The association between perinatal factors and asthma inception is under rigorous investigation. Nevertheless, evidence of a correlation between asthma, conception via in vitro fertilization (IVF) and delivery through Caesarean section (C-section) is inconclusive. OBJECTIVE: We aimed to assess the relation of asthma incidence with IVF and C-section, after controlling for several potential confounding factors. METHODS: Parent-reported wheeze in the last 12 months (current), wheeze ever, physician-diagnosed asthma, method of conception, and type of delivery were recorded from questionnaires filled in by the parents of 2016 Greek children aged 9-13, (the Healthy Growth Study population). Some perinatal data were recorded from children's medical records and others were reported by parents; anthropometric measurements were also conducted in children. RESULTS: IVF was correlated with physician-diagnosed asthma (OR = 2.25; 95% CI = 1.11-4.56), but not with current/ever wheeze after adjustment for potential confounding factors. After adjustment, C-section was also associated with asthma (OR = 1.39; 95% CI = 1.04-1.87), but not with current/ever wheeze. When the association of both IVF and C-section with asthma was examined in the same multivariate logistic regression model, it was weakened to borderline significance (OR = 2.04; 95% CI = 1-4.15 and OR = 1.34; 95% CI = 1-1.81 respectively). CONCLUSIONS AND CLINICAL RELEVANCE: Conception via IVF and delivery by C-section may predispose children to future asthma development. Either variable could also exert a confounding effect on the link of the other to asthma; this may partially be accountable for inconsistencies in the findings of pertinent studies.

The obesity-asthma link in different ages and the role of body mass index in its investigation: findings from the Genesis and Healthy Growth Studies.

BACKGROUND: To date, an obesity/asthma link is well defined in adults; however, the nature of such a link is obscure in children, partly due to Body Mass Index (BMI) limitations as a surrogate fat mass marker in childhood. We thus opted to investigate the association of adiposity with asthma in children of different ages, using several indices to assess fat mass. METHODS: Wheeze ever/in the last 12 months (current) and physician-diagnosed asthma were retrospectively reported via questionnaire by the parents of 3641 children, participating in two cross-sectional studies: 1626 children aged 2-5 (the Genesis Study) and 2015 children aged 9-13 (the Healthy Growth Study). Perinatal data were recorded from the children's medical records or reported by parents. Anthropometric measurements (i.e., BMI, waist/hip circumference, biceps/triceps/subscapular/suprailiac skinfold thickness) were conducted in both cohorts; bioelectric impedance analysis (BIA) was conducted only in preadolescent children. RESULTS: In children aged 2-5, asthma was positively correlated with conicity index, waist/hip circumference, waist-to-height ratio, skinfold thickness, and skinfold-derived percentage fat mass (P < 0.05) but not BMI or BMI-defined overweight/obesity, after adjusting for several confounders. In children aged 9-13, asthma was positively associated with conicity index, waist circumference, waist-to-height ratio, skinfold thickness, skinfold-derived percentage fat mass, BIA-derived percentage fat mass, BMI, and BMI-defined overweight/obesity, following adjustment (P < 0.05). Current/ever wheeze was not consistently associated with fat mass in either population. CONCLUSIONS: Fat mass is positively linked to asthma in both 2-5 and 9-13 age spans. However, the failure of BMI to correlate with preschool asthma suggests its potential inefficiency in asthma studies at this age range.

Exposure of immunologically naive laboratory rodents to antigen via the airways. Where does tolerance stop and sensitization begin?

Conventional rodent models of respiratory allergy that employ intraperitoneal sensitization to aeroallergen plus adjuvant, have offered greatly to our current knowledge of the pathophysiology of allergic airway diseases. Notwithstanding this significant contribution, non-adjuvant aided sensitization via respiratory presentation of the allergen, is more naturally relevant and more closely mimics the human exposure. Nevertheless, in the experimental setting, primary respiratory exposure to inert antigen is likely to lead to inhalation tolerance. Inasmuch as divergent and discrepant results are often reported in experimental models employing this method of sensitization, we set out to review the relative literature and identify and discuss factors that are liable to interfere in such protocols and modify the immune response, hence leading to variable outcomes. Protocol design features (including the use of anaesthesia, the nature and dosage of the antigen and the strain/age/sex and handling of the animals) as well as environmental factors (including airborne substances, viruses and lipopolysaccharide) have been identified as key modulators of the immune response that evolves, following primary airway exposure of laboratory rodents to aeroallergen. Delineation of the effect of those factors to induction or abrogation of inhalation tolerance can have important implications in the design of both improved experimental protocols of respiratory allergy and methods to intercept sensitization to inert aeroallergens in the clinical field.