Pediatric Allergy and Immunology最新文献

Background: Newborns under 6 months of age are at high risk of hospitalization for acute respiratory failure following SARS-CoV-2 infection. Herein, we analyzed neonatal protection against SARS-CoV-2 passively acquired after mother vaccination and/or infection (hybrid immunity).

Methods: We enrolled seventy-eight newborns of immunized mothers against SARS-CoV-2 before or during pregnancy, through vaccination and/or infection. Infants were stratified based on the anamnestic lack (SARS-CoV-2 Vaccinated - SV)/presence (SARS-CoV-2 Infected and Vaccinated - SIV) of COVID-19 maternal infection. SARS-CoV-2-specific Neutralizing Activity (NA) in plasma was assessed by virus neutralization assay (vNTA) against the SARS-CoV-2 Omicron strain at delivery (T0), 3 and 6 months after birth (T3 and T6). Cytokine and chemokine profiles in newborns were also analyzed.

Results: At birth, significantly lower NA was observed in infants of SV compared to that of SIV mothers; NA declined equally in both groups 3 months after delivery. The presence of at least 4 immunizing events in the mother significantly enhances the NA against SARS-CoV-2 in newborns, regardless of the type of immunization (vaccination or hybrid immunity) and of the timing of the last maternal immunization. Finally, cytokines and chemokines plasma levels were high at birth in all newborns, followed by a decline over the subsequent month.

Conclusion: Our findings suggest that, independently of a previous SARS-CoV-2 infection or vaccination, it is reasonable to upgrade the recommendation of a booster dose during pregnancy to a "strongly recommended" status, with a view to conferring protection to newborns in the first months after delivery.

Background: Allergic bronchopulmonary aspergillosis (ABPA) is a hypersensitivity response to the allergens of Aspergillus fumigatus, which is the most frequently isolated fungus from the sputum of cystic fibrosis (CF) patients. Because a low number of Th17 lymphocytes is associated with the risk of fungal infections, we investigated inflammatory markers, Th17 cells, and T-cell polarization in CF patients with ABPA.

Methods: We analyzed the levels of inflammatory markers, blood counts, chemokines, cytokines, and T cell subsets in blood and sputum of CF subjects to elucidate the immunological factors associated with CF patients with Aspergillus fumigatus (AF) positive sputum (AFS⁺) or with ABPA.

Results: We observed that AFS+ patients have higher sputum and blood IL-6 levels than AF-negative sputum (AFS^-) patients. Analysis of blood memory T-helper subsets associated with Th1, Th2, and Th17 polarization among circulating CD45RA-/CD4+ memory T-cell subsets showed higher numbers of CCR4⁺/CCR6⁺/CXCR3^- and CCR4⁺/CCR6⁺/CXCR3⁺ memory CD4 cells in AFS+ compared to AFS^- subjects. Further analysis of Th17-related subsets and IL-17 secreting T cells in subjects with AFS+ showed that those with ABPA have statistically significantly lower levels of Th17 cells as compared to those without ABPA.

Conclusion: In CF, AF airway colonization is associated with increased blood counts of Th17-related subsets. However, CF patients with ABPA exhibit lower numbers of CCR4+/CCR6+/CXCR3+ memory CD4 cells and IL-17-secreting CD4 cells compared to control subjects and CF patients without AF sensitization.

Background: Immunoglobulin (Ig)E deficiency (<2.5 IU/mL) in adults is linked to higher risks of cancer and autoimmunity, but its significance in children remains unclear. This study evaluates the clinical importance of IgE deficiency in a nationwide pediatric cohort.

Methods: A retrospective, population-based study included 123,393 Israeli children tested for IgE levels between 2002 and 2022. Participants were categorized into four groups: deficient (<2.5 IU/mL), normal (2.5-100 IU/mL), high (100-1000 IU/mL), and very high (≥1000 IU/mL). Outcomes included cancer, inborn errors of immunity (IEI), and autoimmune disorders, with up to 5 years of follow-up. The data were analyzed using univariable methods and multivariable Cox regression.

Results: Among the cohort, 2114 children (1.71%) had IgE deficiency, with a mean age of 3.73 years. Most (95.60%) were tested only once. IgE deficiency was associated with increased risks of solid tumors (HR = 2.721; 95% CI: 1.313-5.638), IEI (HR = 1.646; 95% CI: 1.095-2.474), and autoimmune disorders (HR = 1.266; 95% CI: 1.099-1.458) compared to normal IgE levels. No link was found between IgE deficiency and hematological malignancies. Selective IgM deficiency was the most common IEI associated with IgE deficiency (40%). Asthma prevalence was highest in children with very high IgE (N = 5574; 57.01%) and lowest in the normal IgE group (N = 24,171; 38.91%). The IgE-deficient group fell in the middle range (N = 903; 42.72%). In IgE-deficient children, allergic rhinitis was less common (11.26% vs. 14.09%).

Conclusion: IgE deficiency in children is associated with higher risks of solid tumors, autoimmune disorders, and IEI, suggesting potential immune dysregulation. Close monitoring of IgE-deficient children should be considered.

Background: Various observational studies have suggested that infants and young children who regularly sleep in synthetic bedding materials are more likely to experience wheezing and asthma, while children who use feather duvets and/or feather pillows are less likely to wheeze.

Methods: In Wellington, New Zealand, we conducted a three-armed, parallel, randomised trial of 460 infants who were assigned to use different bedding materials: synthetic, wool or feather bedding in the form of sleepsacks from 3 months of age to 2 years of age to test the hypothesis that children exposed to feather materials are less likely to develop wheezing. Pregnant women were recruited before birth. Parents were unaware of the primary research hypothesis and were told this was a study of child warmth and wheezing. We have reported wheezing (parental and GP), a variety of respiratory health parameters and atopic status at 2 years.

Results: One hundred and forty-seven infants received a synthetic sleepsack, 150 wool and 144 feather. We have found no significant differences in reported or doctor-diagnosed wheezing or other respiratory health measures by bedding material used. For frequency of wheezing presentation at GP surgery, there was a significant increased rate for children using feather materials compared to synthetic, relative rate 2.00 (95% CI: 1.14, 3.52).

Conclusion: This study does not support earlier observational studies that suggest higher rates of wheezing for children using synthetic bedding or lower rates for feather materials, at least for early childhood wheezing. Our study suggests that the explanation for the observational study findings may lie in selection bias, where the parents of at-risk children avoid feather bedding materials.

Background: Acute bronchiolitis is the leading cause of hospitalization in infants, and air pollutants represent a risk factor for its development. This work aims to investigate the role of air pollution, considering conventional and nonconventional indicators, in the development of bronchiolitis in three urban areas in the Po Valley, Northern Italy.

Methods: This multicentric, observational, retrospective, cohort study included infants under 12 months who were referred to the Pediatric Emergency Department of Bologna, Belluno, and Biella and diagnosed with bronchiolitis from 2016 to 2019. Data on daily ground-level mass concentrations of particulate matter (PM₁₀ and PM_2.5) and gaseous pollutants in the three areas, and additionally of organic carbon (OC) and elemental carbon (EC) in Bologna, were retrieved and assessed for possible relationships with the occurrence of bronchiolitis.

Results: A total of 1316 patients were enrolled. All conventional air quality indicators (NO₂, PM₁₀, and PM_2.5) showed statistically significant associations with the occurrence of referrals due to bronchiolitis. The highest impacts were observed for OC and EC, the carbonaceous components of PM, which were only measured in Bologna. Considering the conventional indicators, the strongest associations were found between 4-week moving average concentrations and weekly hospital admission, and the strongest associations were found considering NO₂ and PM_2.5.

Conclusion: This study indicates that medium-term exposure to higher levels of air pollution increases the risk of the development of bronchiolitis. In particular, the best association results between bronchiolitis admissions and the exposure to the carbonaceous fraction of PM_2.5.