DNA methylation (DNAm) has been shown to play a role in mediating food allergy, however, the mechanism by which it does so is poorly understood. In this study, we used targeted NextGen bisulfite sequencing to evaluate DNAm levels in 125 targeted highly informative genomic regions containing 602 CpG sites on 70 immune-related genes to understand whether DNAm can differentiate peanut allergy (PA) vs non-allergy (NA). We found PA-associated DNAm signatures associated with 12 genes (7 potentially novel to food allergy, 3 associated with Th1/Th2, and 2 associated with innate immunity) as well as DNAm signature combinations with superior diagnostic potential compared to serum peanut specific-IgE for PA vs. NA. Further, we found that following peanut protein stimulation, peripheral blood mononuclear cell (PBMCs) from PA participants showed increased production of cognate cytokines compared to NA participants. The varying responses between PA and NA participants may be associated with the interaction between the modification of DNAm and the interference of environment. Using Euclidean distance analysis, we found that the distances of methylation profile comprising 12 DNAm signatures between PA and NA pairs in monozygotic (MZ) twins were smaller than that in randomly paired genetically unrelated individuals, suggesting that PA related DNAm signatures may be associated with genetic factors.

Background: It is unclear if asthma and its allergic phenotype are risk factors for hospitalization or severe disease from SARS-CoV-2. Methods: All patients testing positive for SARS-CoV-2 between March 1 and September 30, 2020, were retrospectively identified and characterized through electronic analysis at Stanford. A sub-cohort was followed prospectively to evaluate long-term COVID-19 symptoms. Results: 168,190 patients underwent SARS-CoV-2 testing, and 6,976 (4·15%) tested positive. In a multivariate analysis, asthma was not an independent risk factor for hospitalization (OR 1·12 [95% CI 0·86, 1·45], p=0·40). Among SARS-CoV-2 positive asthmatics, allergic asthma lowered the risk of hospitalization and had a protective effect compared to non-allergic asthma (OR 0·52 (0·28, 0·91), p=0·026); there was no association between baseline medication use as characterized by GINA and hospitalization risk. Patients with severe COVID-19 disease had lower eosinophil levels during hospitalization compared to patients with mild or asymptomatic disease, independent of asthma status (p=0.0014). In a patient sub-cohort followed longitudinally, asthmatics and non-asthmatics had similar time to resolution of COVID-19 symptoms, particularly lower respiratory symptoms. Conclusions: Asthma is not a risk factor for more severe COVID-19 disease. Allergic asthmatics were half as likely to be hospitalized with COVID-19 compared to non-allergic asthmatics. Lower levels of eosinophil counts (allergic biomarkers) were associated with more severe COVID-19 disease trajectory. Recovery was similar among asthmatics and non-asthmatics with over 50% of patients reporting ongoing lower respiratory symptoms three months post-infection.

Background Ambient air pollutant (AAP) exposure is associated with adverse pregnancy outcomes, such as preeclampsia, preterm labor, and low birth weight. Previous studies have shown methylation of immune genes associate with exposure to air pollutants in pregnant women, but the cell-mediated response in the context of typical pregnancy cell alterations has not been investigated. Pregnancy causes attenuation in cell-mediated immunity with alterations in the Th1/Th2/Th17/Treg environment, contributing to maternal susceptibility. We recruited women (n = 186) who were 20 weeks pregnant from Fresno, CA, an area with chronically elevated AAP levels. Associations of average pollution concentration estimates for 1 week, 1 month, 3 months, and 6 months prior to blood draw were associated with Th cell subset (Th1, Th2, Th17, and Treg) percentages and methylation of CpG sites (IL4, IL10, IFNγ, and FoxP3). Linear regression models were adjusted for weight, age, season, race, and asthma, using a Q value as the false-discovery-rate-adjusted p-value across all genes. Results Short-term and mid-term AAP exposures to fine particulate matter (PM2.5), nitrogen dioxide (NO2) carbon monoxide (CO), and polycyclic aromatic hydrocarbons (PAH456) were associated with percentages of immune cells. A decrease in Th1 cell percentage was negatively associated with PM2.5 (1 mo/3 mo: Q < 0.05), NO2 (1 mo/3 mo/6 mo: Q < 0.05), and PAH456 (1 week/1 mo/3 mo: Q < 0.05). Th2 cell percentages were negatively associated with PM2.5 (1 week/1 mo/3 mo/6 mo: Q < 0.06), and NO2 (1 week/1 mo/3 mo/6 mo: Q < 0.06). Th17 cell percentage was negatively associated with NO2 (3 mo/6 mo: Q < 0.01), CO (1 week/1 mo: Q < 0.1), PM2.5 (3 mo/6 mo: Q < 0.05), and PAH456 (1 mo/3 mo/6 mo: Q < 0.08). Methylation of the IL10 gene was positively associated with CO (1 week/1 mo/3 mo: Q < 0.01), NO2 (1 mo/3 mo/6 mo: Q < 0.08), PAH456 (1 week/1 mo/3 mo: Q < 0.01), and PM2.5 (3 mo: Q = 0.06) while IL4 gene methylation was positively associated with concentrations of CO (1 week/1 mo/3 mo/6 mo: Q < 0.09). Also, IFNγ gene methylation was positively associated with CO (1 week/1 mo/3 mo: Q < 0.05) and PAH456 (1 week/1 mo/3 mo: Q < 0.06). Conclusion Exposure to several AAPs was negatively associated with T-helper subsets involved in pro-inflammatory and anti-inflammatory responses during pregnancy. Methylation of IL4, IL10, and IFNγ genes with pollution exposure confirms previous research. These results offer insights into the detrimental effects of air pollution during pregnancy, the demand for more epigenetic studies, and mitigation strategies to decrease pollution exposure during pregnancy.

Background The impact of exposure to air pollutants, such as fine particulate matter (PM), on the immune system and its consequences on pediatric asthma, are not well understood. We investigated whether ambient levels of fine PM with aerodynamic diameter ≤2.5 microns (PM2.5) are associated with alterations in circulating monocytes in children with or without asthma. Methods Monocyte phenotyping was performed by cytometry time‐of‐flight (CyTOF). Cytokines were measured using cytometric bead array and Luminex assay. ChIP‐Seq was utilized to address histone modifications in monocytes. Results Increased exposure to ambient PM2.5 was linked to specific monocyte subtypes, particularly in children with asthma. Mechanistically, we hypothesized that innate trained immunity is evoked by a primary exposure to fine PM and accounts for an enhanced inflammatory response after secondary stimulation in vitro. We determined that the trained immunity was induced in circulating monocytes by fine particulate pollutants, and it was characterized by the upregulation of proinflammatory mediators, such as TNF, IL‐6, and IL‐8, upon stimulation with house dust mite or lipopolysaccharide. This phenotype was epigenetically controlled by enhanced H3K27ac marks in circulating monocytes. Conclusion The specific alterations of monocytes after ambient pollution exposure suggest a possible prognostic immune signature for pediatric asthma, and pollution‐induced trained immunity may provide a potential therapeutic target for asthmatic children living in areas with increased air pollution.

The impact of exposure to air pollutants, such as fine particulate matter (PM), on the immune system and its consequences on pediatric asthma are not well understood. We investigated whether the ambient levels of fine PM with aerodynamic diameter ≤ 2.5 microns (PM ) are associated with alterations in circulating monocytes in children with or without asthma. Increased exposure to ambient PM was linked to specific monocyte subtypes, particularly in children with asthma. Mechanistically, we hypothesized that innate trained immunity is evoked by a primary exposure to fine PM and accounts for an enhanced inflammatory response after secondary stimulation in vitro. We determined that the trained immunity was induced in circulating monocytes by fine particulate pollutants, and it was characterized by upregulation of proinflammatory mediators, such as TNF, IL-6, and IL-8, upon stimulation with house dust mite or LPS. This phenotype was epigenetically controlled by enhanced H3K27ac marks in circulating monocytes. The specific alterations of monocytes after ambient pollution exposure suggest a possible prognostic immune signature for pediatric asthma, and pollution-induced trained immunity may provide a potential therapeutic target for asthmatic children living in areas with increased air pollution.