Project description:B-cell precursor acute lymphoblastic leukemia (BCP-ALL) is the most common form of childhood cancer. Chemotherapy is associated with life-long health sequelae and fails in ∼20% of cases. Thus, prevention of leukemia would be preferable to treatment. Childhood leukemia frequently starts before birth, during fetal hematopoiesis. A first genetic hit (eg, the ETV6-RUNX1 gene fusion) leads to the expansion of preleukemic B-cell clones, which are detectable in healthy newborn cord blood (up to 5%). These preleukemic clones give rise to clinically overt leukemia in only ∼0.2% of carriers. Experimental evidence suggests that a major driver of conversion from the preleukemic to the leukemic state is exposure to immune challenges. Novel insights have shed light on immune host responses and how they shape the complex interplay between (1) inherited or acquired genetic predispositions, (2) exposure to infection, and (3) abnormal cytokine release from immunologically untrained cells. Here, we integrate the recently emerging concept of "trained immunity" into existing models of childhood BCP-ALL and suggest future avenues toward leukemia prevention.
Project description:Evidence suggests vitamin D has preventive potential in asthma; however, not all children benefit from this intervention. This study aimed to investigate whether variation in the functional 17q21 single nucleotide polymorphism rs12936231 affects the preventive potential of vitamin D against asthma.A combined secondary analysis of two randomised controlled trials of prenatal vitamin D supplementation for the prevention of asthma in offspring (Vitamin D Antenatal Asthma Reduction Trial (VDAART) and Copenhagen Prospective Studies on Asthma in Childhood 2010 (COPSAC2010)) was performed, stratifying by genotype and integrating metabolite data to explore underlying mechanisms.The protective effect of vitamin D on asthma/wheeze was evident among children with the low-risk rs12936231 GG genotype (hazard ratio (HR) 0.49, 95% CI 0.26-0.94, p=0.032) but not the high-risk CC genotype (HR 1.08, 95% CI 0.69-1.69, p=0.751). In VDAART, in the GG genotype vitamin D supplementation was associated with increased plasma levels of sphingolipids, including sphingosine-1-phosphate (? 0.022, 95% CI 0.001-0.044, p=0.038), but this was not evident with the CC genotype, known to be associated with increased expression of ORMDL3 in bronchial epithelial cells. Sphingolipid levels were associated with decreased risk of asthma/wheeze, and there was evidence of interactions between sphingolipid levels, vitamin D and genotype (p-interactionvitaminD*genotype*sphingosine-1-phosphate=0.035). In a cellular model, there was a significant difference in the induction of sphingosine-1-phosphate by vitamin D between a control human bronchial epithelial cell line and a cell line overexpressing ORMDL3 (p=0.002).Results suggest prenatal vitamin D supplementation may reduce the risk of early childhood asthma/wheeze via alterations of sphingolipid metabolism dependent on the 17q21 genotype.
Project description:BackgroundLower respiratory tract infection (LRTI) caused by respiratory syncytial virus (RSV) has been associated with greater risk of recurrent wheezing and subsequent asthma. However, it is still unclear whether this association is causal or not. RSV-specific monoclonal antibodies have been shown to reduce RSV-related hospitalisations in high-risk infants, i.e. those born pre-term, but the longer term follow-up has given conflicting evidence for the prevention of recurrent wheeze or asthma.ObjectiveWe aim to perform a systematic review and meta-analysis to determine whether or not prophylaxis with a monoclonal antibody for prevention of RSV-bronchiolitis reduces the risk of subsequent recurrent wheeze or asthma. If so, this would support the hypothesis that the association between RSV and recurrent wheeze and/or asthma is causative.MethodsTo identify relevant studies, we will search a number of databases including Medline, Embase, PubMed and Web of Science and will also manually look for unpublished data by contacting the manufacturers of monoclonal antibodies. The intervention being investigated is RSV-specific monoclonal antibody prophylaxis, and the outcome being measured is recurrent wheeze and/or asthma. Studies will be screened according to inclusion/exclusion criteria, to include primary studies of any study design type. Eligible studies will then be evaluated for quality and assessed for bias independently by three reviewers using the 'Grading of Recommendations Assessment, Development and Evaluation' (GRADE) approach. The results of the studies will be extracted into 2?×?2 outcome tables, and a meta-analysis will be carried out to produce forest plots based on relative risk. Heterogeneity will be assessed using the I2 statistic. The statistical software we will use is StatsDirect.DiscussionThis review will aid in determining if the relationship between RSV and asthma development is a causal one, by showing the effect (if any) of RSV prophylaxis on subsequent recurrent wheeze/asthma. If this study shows RSV prophylaxis to have no effect on the outcome of recurrent wheeze/asthma, the question of causality remains.
Project description:Phenotypic variation in asthma, especially early childhood asthma, is increasingly recognized. Although inhaled corticosteroids are recommended as first-line therapy, it has less efficacy in controlling intermittent wheeze due to viral-induced symptoms in early childhood. This article reviews 2 emerging therapies in particular for early childhood wheeze: azithromycin and bacterial lysate therapy. Azithromycin's effects are both antibacterial and anti-inflammatory, and it has been shown in 2 studies in preschoolers to prevent progression to severe respiratory tract infection and decrease duration of wheeze. Bacterial lysates work at multiple stages in the innate and adaptive immune response and have been shown to decrease mean wheeze duration in particular in the preschool age. More research is required although both therapies offer a promising future approach, in particular in the nonatopic preschool wheezer, as we move toward a more personalized approach to childhood asthma.
Project description:Background: We recently published two independent randomized controlled trials of vitamin D supplementation during pregnancy, both indicating a >20% reduced risk of asthma/recurrent wheeze in the offspring by 3 years of age. However, neither reached statistical significance.Objective: To perform a combined analysis of the two trials and investigate whether maternal 25-hydroxy-vitamin D (25(OH)D) level at trial entry modified the intervention effect.Methods: VDAART (N = 806) and COPSAC2010. (N = 581) randomized pregnant women to daily high-dose vitamin D3 (4,000 IU/d and 2,400 IU/d, respectively) or placebo. All women also received a prenatal vitamin containing 400 IU/d vitamin D3. The primary outcome was asthma/recurrent wheeze from 0-3yrs. Secondary end-points were specific IgE, total IgE, eczema and lower respiratory tract infections (LRTI). We conducted random effects combined analyses of the treatment effect, individual patient data (IPD) meta-analyses, and analyses stratified by 25(OH)D level at study entry.Results: The analysis showed a 25% reduced risk of asthma/recurrent wheeze at 0-3yrs: adjusted odds ratio (aOR) = 0.74 (95% CI, 0.57-0.96), p = 0.02. The effect was strongest among women with 25(OH)D level ?30ng/ml at study entry: aOR = 0.54 (0.33-0.88), p = 0.01, whereas no significant effect was observed among women with 25(OH)D level <30ng/ml at study entry: aOR = 0.84 (0.62-1.15), p = 0.25. The IPD meta-analyses showed similar results. There was no effect on the secondary end-points.Conclusions: This combined analysis shows that vitamin D supplementation during pregnancy results in a significant reduced risk of asthma/recurrent wheeze in the offspring, especially among women with 25(OH)D level ? 30 ng/ml at randomization, where the risk was almost halved. Future studies should examine the possibility of raising 25(OH)D levels to at least 30 ng/ml early in pregnancy or using higher doses than used in our studies.Trial registration: COPSAC2010: ClinicalTrials.gov NCT00856947; VDAART: ClinicalTrials.gov NCT00920621.
Project description:Prenatal folic acid supplementation is recommended to prevent birth defects. Some foods are fortified in the USA to ensure sufficient intake among reproductive-aged women. However, high prenatal folate exposure may be a risk factor for childhood atopic diseases. We investigated associations between prenatal folate and early childhood wheeze and atopic dermatitis in a US cohort.We studied 858 mother-child dyads, enrolled prenatally. Folate was measured in 2nd and 3rd trimester maternal plasma. Parents reported current wheeze (previous 12 months) and healthcare provider diagnosis of atopic dermatitis at 3 years. We examined associations using logistic regression, modeling folate continuously and dichotomously (< or ?20 ng/mL), a level often considered supraphysiologic.Over half of women were African American and on Medicaid. Median (interquartile range) folate levels were 22.6 (15.9-30.0) and 23.1 (16.1-30.0) ng/mL for 2nd and 3rd trimesters, respectively. Current wheeze and atopic dermatitis were reported for 20.4% and 26.8% of children, respectively. Second trimester folate as a continuous exposure was not significantly associated with outcomes. Decreased odds of current wheeze were observed in children born to mothers who had 2nd trimester folate ?20 ng/mL (adjusted odds ratios = 0.67, 95% confidence interval = 0.46, 0.97) compared to children with maternal levels <20 ng/mL. Third trimester folate was not associated with outcomes.High plasma folate in mid-pregnancy was associated with decreased odds of current wheeze at age 3. Our findings do not support harmful effects of high prenatal folate levels on childhood atopic diseases in this setting.
Project description:BACKGROUND:Disadvantaged urban children have high rates of allergic diseases and wheezing, which are diseases associated with type 2-biased immunity. OBJECTIVE:We sought to determine whether environmental exposures in early life influence cytokine responses that affect the development of recurrent wheezing illnesses and allergic sensitization. METHODS:A birth cohort of 560 urban families was recruited from neighborhoods with high rates of poverty, and 467 (83%) children were followed until 3 years of age. Cytokine responses were measured in blood cell samples obtained at birth (cord blood) and ages 1 and 3 years. Cytokine responses were examined in relation to personal characteristics and environmental exposures to allergens and endotoxin and to the development of allergic sensitization and recurrent wheeze assessed at age 3 years. RESULTS:Cytokine responses generally increased with age, but responses at birth were poorly predictive for those at ages 1 and 3 years. Exposure to certain allergens (cockroach, mouse, dust mite) was significantly associated with enhanced cytokine responses at age 3 years, including IFN-? and IL-10 responses to certain stimulants and responses to phytohemagglutinin. Regarding the clinical outcomes, reduced LPS-induced IL-10 responses at birth were associated with recurrent wheeze. In contrast, reduced respiratory syncytial virus-induced IL-8 responses and increased 5'-cytosine-phosphate-guanine-3' (CpG)-induced IL-12p40 and allergen-induced IL-4 responses were associated with atopy. CONCLUSIONS:These findings suggest that diverse biologic exposures, including allergens and endotoxin, in urban homes stimulate the development of cytokine responses in early life, and that cytokine responses to specific microbial and viral stimuli are associated with the development of allergic sensitization and recurrent wheeze.
Project description:BackgroundWheeze and allergic sensitization are the strongest early-life predictors of childhood asthma development; the molecular origins of these early-life phenotypes are poorly understood.ObjectivesWe sought to identify metabolites associated with early-life wheeze, allergic sensitization, and childhood asthma.MethodsWe conducted a nested case-control study using Environmental influences on Child Health Outcomes Program cohorts for discovery and independent replication. Wheeze and allergic sensitization were defined by number of wheeze episodes and positive specific IgE at age 1 year, respectively. Asthma was defined as physician diagnosis of asthma at age 5 or 6 years. We used untargeted metabolomics, controlling for observed and latent confounding factors, to assess associations between the plasma metabolome and early-life wheeze, allergy, and childhood asthma.ResultsEighteen plasma metabolites were associated with first-year wheeze in the discovery cohort (n = 338). Z,Z unconjugated bilirubin (UCB) and its related metabolites exhibited a dose-response relationship with wheeze frequency; UCB levels were 13% (β = 0.87; 95% CI, 0.74-1.02) and 22% (β = 0.78; 95% CI, 0.68-0.91) lower in children with 1 to 3 and 4+ wheeze episodes compared with those who never wheezed, respectively. UCB levels were also associated with childhood asthma (β = 0.82; 95% CI, 0.68-0.98). Similar trends were observed in 2 independent cohorts. UCB was significantly negatively correlated with eicosanoid- and oxidative stress-related metabolites. There were no significant associations between metabolites and allergic sensitization.ConclusionsWe identified a novel inverse, dose-dependent association between UCB and recurrent wheeze and childhood asthma. Inflammatory lipid mediators and oxidative stress byproducts inversely correlated with UCB, suggesting that UCB modulates pathways critical to the development of early-life recurrent wheeze and childhood asthma.
Project description:Air pollution exposures have been suggested as risk factors for childhood respiratory diseases. We investigated proximity to major roads, an indicator of air pollution exposure, and its associations with childhood recurrent wheeze and asthma. We used data from a multicenter prospective cohort study of 921 infants hospitalized for bronchiolitis and recruited from 14 U.S. states. Primary exposure was residential proximity to the nearest major road at birth through age 3 years. Residential distance from nearest major road was divided into four categories: <100, 100-200, 201-300, and >300 m. Outcomes were parent-reported recurrent wheeze by age 3 years and asthma by age 5 years. Associations between residential proximity to major roads and respiratory outcomes were investigated using multivariable Cox proportional hazards modeling and logistic regression, adjusted for confounders. Out of 920 participants with home address data, pooled estimates identified 241 (26%) participants resided within 300 m of a major road, 296 (32%) developed recurrent wheeze by age 3, and 235 out of 858 participants (27%) developed asthma by 5 years. Participants who resided close to a major road had the highest risk of recurrent wheeze (adjusted hazards ratio for <100 m, 1.59, 95%CI: 1.08-2.33) and asthma (adjusted odds ratio for 201-300 m, 1.62, 95%CI: 1.16-2.25), compared to those residing >300 m from a major road. Proximity to major roads is associated with increased risks of recurrent wheeze and asthma in young children.
Project description:Although sexual dimorphism in wheeze and asthma prevalence are well documented, sex-specific risk factors for wheeze and longitudinal wheeze phenotypes have not been well elucidated.By using a large prebirth cohort, this study aimed to identify sex-specific risk factors for wheeze from birth through midchildhood and identify distinct longitudinal wheeze phenotypes and the sex-specific risk factors associated with these phenotypes.Mothers reported child wheeze symptoms over the past year approximately yearly on 9 occasions starting at age 1 year. We identified sex-specific predictors of wheeze, wheeze phenotypes, and sex-specific predictors of these phenotypes by using generalized estimating equations, latent class mixed models, and multinomial logistic analysis, respectively.A total of 1623 children had information on wheeze at 1 or more time points. Paternal asthma was a stronger predictor of ever wheezing in boys (odds ratio [OR], 2.15; 95% CI, 1.74-2.66) than in girls (OR, 1.53; 95% CI, 1.19-1.96; P for sex by paternal asthma interaction = .03), whereas being black or Hispanic, birth weight for gestational age z score, and breast-feeding duration had stronger associations among girls. We identified 3 longitudinal wheeze phenotypes: never/infrequent wheeze (74.1%), early transient wheeze (12.7%), and persistent wheeze (13.1%). Compared with never/infrequent wheeze, maternal asthma, infant bronchiolitis, and atopic dermatitis were associated with persistent wheeze in both sexes, but paternal asthma was associated with persistent wheeze in boys only (OR, 4.27; 95% CI, 2.33-7.83; P for sex by paternal asthma interaction = .02), whereas being black or Hispanic was a predictor for girls only.We identified sex-specific predictors of wheeze and longitudinal wheeze patterns, which might have important prognostic value and allow for a more personalized approach to wheeze and asthma treatment.