Project Summary Proteomics analysis of URECA nasal secretions. Rationale. The URECA 14-17 year time point includes collection of nasal secretions by nasosorption to complement information that will be gained by analyzing nasal cell RNA and DNA. Analysis of nasal specimens collected at 11 year of age indicates that children with allergic asthma or chronic rhinitis have distinct differences in nasal epithelial cell gene expression that include increased expression of T2 genes and reduced expression of an array of other immune response genes. For example, children with a history of chronic rhinitis beginning in early life have downregulation of a network of genes including canonical antiviral genes (STAT1, IRF1) but also genes involved in other innate immune responses (e.g., GSMA, CCL5) and adaptive immune responses (HLA-DRA, CD4, CD19). Notably, there is a strong negative correlation between the upregulated T2 cluster and the downregulation of other immune response genes. These findings suggest that T2 inflammation can suppress a variety of mucosal immune responses, including antiviral, antibacterial, and innate and adaptive responses. Preliminary data. To further explore the hypothesis that airway mucosal immunity is depressed in children with allergic rhinitis, we have analyzed nasal secretions from children enrolled in the Childhood Origins of Asthma (COAST study). Nasal secretions were obtained by “nasal blow” from 9 y/o children who were sensitized to aeroallergens and reported at least moderate nasal symptoms, and an equal number of children with neither symptoms nor sensitization (10 per group). The nasal samples were tested for immunoglobulin content by multiplex ELISA (Milliplex, Millipore). IgE values were low at the threshold of detection for this assay (40% undetectable), and not significantly different between the groups (geomean 6 vs. 3 ng/mL, allergic vs. nonallergic respectively, ns). However, children with allergic rhinitis had generally lower immunoglobulin levels than the normal controls (Figure). However, there were significant differences Figure _. Immunoglobulin levels in nasal secretions from allergic and nonallergic children. Geometric means +/- SD. (p<0.05) in other immunoglobulins in nasal secretions including IgM (48 vs. 11 pg/mL), IgG2 (1365 vs. 196 pg/mL) and IgA (124 vs. 23 ng/mL). These findings suggest that allergic rhinitis is associated with reduced immunoglobulins in nasal secretions, and that this could be related to greater susceptibility to both viral and bacterial infections. Experimental design. We proposal to conduct a pilot study with 12 samples of nasal secretions (nasosorption) from URECA children with allergic rhinitis (aeroallergen sensitization and nasal symptoms) and 12 samples from children with neither allergy nor allergic sensitization. We will use mass spectrometry (LC/MS/MS, UW A.I.C. Mass Spectrometry Facility) to identify proteins in the secretions. Samples of nasal secretions are stored in PBS...