Supplementary Material for: Distinct Gene Expression Patterns between Nasal Mucosal Cells and Blood Collected from Allergic Rhinitis Sufferers

Background: Investigations of gene expression in allergic rhinitis (AR) typically rely on invasive nasal biopsies (site of inflammation) or blood samples (systemic immunity) to obtain sufficient genetic material for analysis. New methodologies to circumvent the need for invasive sample collection offer promise to further the understanding of local immune mechanisms relevant in AR. Methods: A within-subject design was employed to compare immune gene expression profiles obtained from nasal washing/brushing and whole blood samples collected during peak pollen season. Twelve adults (age: 46.3 ± 12.3 years) with more than a 2-year history of AR and a confirmed grass pollen allergy participated in the study. Gene expression analysis was performed using a panel of 760 immune genes with the NanoString nCounter platform on nasal lavage/brushing cell lysates and compared to RNA extracted from blood. Results: A total of 355 genes were significantly differentially expressed between sample types (9.87 to –9.71 log₂ fold change). The top 3 genes significantly upregulated in nasal lysate samples were Mucin 1 (MUC1), Tight Junction Protein 1 (TJP1), and Lipocalin-2 (LCN2). The top 3 genes significantly upregulated in blood samples were cluster of differentiation 3e (CD3E), FYN Proto-Oncogene Src Family Tyrosine Kinase (FYN) and cluster of differentiation 3d (CD3D). Conclusions: Overall, the blood and nasal lavage samples showed vastly distinct gene expression profiles and functional gene pathways which reflect their anatomical and functional origins. Evaluating immune gene expression of the nasal mucosa in addition to blood samples may be beneficial in understanding AR pathophysiology and response to allergen challenge.