AbstractBackgroundOdontogenic sinusitis (ODS) is distinct from non‐odontogenic rhinosinusitis with regard to clinical features as well as diagnostic and therapeutic approaches. While numerous studies have explored immune profiles of chronic rhinosinusitis, very few studies have explored the inflammatory endotype of ODS.MethodsOdontogenic sinusitis was diagnosed by confirming infectious sinusitis adjacent to infectious maxillary odontogenic pathology. Maxillary sinus cultures and mucosal biopsies were obtained during endoscopic endonasal surgery in ODS and control patients. Controls were patients undergoing endoscopic skull base surgery with no sinus disease. Specimens were snap frozen in liquid nitrogen and stored at −80°C. Analysis was performed using a multiplex assay to measure Th‐1 (TNFα, IFNγ, IL‐2,12,18), Th‐2 (IL‐4,5,9,13), Th‐17 (IL‐17A,17F,22), and innate (CCL5,CXCL9,CXCL10, IL‐6,8,10,12,23,27) immune pathways. Groups were compared via independent sample t‐tests; if assumptions were violated, nonparametric Wilcoxon ranked sum tests were performed.ResultsSpecimens from 22 ODS patients were compared to nine controls. ODS mucosal tissue was sampled in the setting of the following dental pathologies: post‐dental extraction (n = 15), untreated apical periodontitis (n = 2), apical periodontitis after root canal therapy (n = 2), and maxillary sinus bone grafting with or without dental implantation (n = 3). The following cytokines were significantly elevated in ODS compared to controls: IFNγ, TNFα, IL‐6, 8, 10, 27, and CXCL9. IL‐17 levels were similar in both ODS and controls. Therefore, ODS demonstrated heightened innate and Th1 immune activity.ConclusionODS demonstrated both innate immune and Th1 inflammatory endotypes. Further studies are needed to explore ODS immunopathobiology and its potential impact on ODS management.