AbstractObjectiveTo present a comprehensive flow cytometry panel for idiopathic subglottic stenosis (iSGS).Study DesignControlled ex vivo cohort study.SettingTertiary care academic hospital in a metropolitan area.MethodsFlow cytometry and single‐cell RNA sequencing were performed on 9 paired normal and scar tissue samples from iSGS patients. Flow cytometry was used to assess the presence of myeloid (CD11b, CD14, CD15, Siglec8), lymphoid (CD3, CD4, CD8, gamma delta [γδ], FOXP3), endothelial (CD31), fibroblast (CD90, SMA), and epithelial (CD326, CK5) markers.ResultsOn flow cytometry, iSGS scar is characterized by an increased presence of myeloid, lymphoid, endothelial, and fibroblast cell types, but a decreased presence of epithelial cells. In the myeloid lineage, iSGS scar samples demonstrated increased CD11b+ monocytes (P < .001), Siglec8+ eosinophils (P = .03), and CD14+ monocytes (P = .02). In the lymphoid lineage, iSGS scar demonstrated increased CD3+ T‐cells (P < .001), CD4+ helper T‐cells (P < .001), γδ+ T‐cells (P < .001), and FOXP3+ regulatory T‐cells (P = .002). iSGS scar exhibited specific increases in CD90+ (P = .04) and SMA+ (P < .001) fibroblasts but decreased CD326+ (E‐cadherin) epithelial cells (P = .01) relative to normal samples.ConclusionWe present a comprehensive flow cytometry panel for iSGS. This flow panel may serve as a common platform among airway scientists to elucidate the cellular mechanisms underpinning iSGS and other upper airway pathologies. Scar iSGS samples demonstrate a distinct cellular profile relative to normal iSGS specimens, exhibiting increased fibroblast, endothelial, and inflammatory cell types but decreased epithelium.