Transcriptome profiling of T-helper cells from normal nassal mucosa and matched peripheral blood

Background: Chronic rhinosinusitis with nasal polyposis (CRSwNP) in western countries is characterized by eosinophilia, IgE production and Th2 cytokine expression. Type 2 innate lymphoid cells (ILC2) from polyps produce IL-5 and IL-13 in response to IL-25 and IL-33 although the relevance of this axis to local mucosal T cell responses is unknown. Objective: To investigate the role of the IL-25/IL-33 axis in local mucosal T cell responses in CRSwNP. Methods: Polyp tissue and blood were obtained from patients undergoing nasal polypectomy. Control nasal biopsies and blood were obtained from healthy volunteers. Tissue was cultured in a short-term explant model. T cell surface phenotype/intracellular cytokines were assessed by flow cytometry. TCR Vβ analysis was performed with the immunoSEQ assay. Microarrays were performed for gene expression analysis. Results: Using nasal polyp tissue, numerous IL-25 receptor (IL-17RB) positive polarized Th2 cells were identified which were absent in the healthy nasal mucosa and periphery. IL-17RB+CD4+ polyp Th2 cells co-expressed ST2 (IL-33 receptor) and responded to IL-25 and IL-33 with enhanced IL-5 and IL-13 production. Within IL-17RB+CD4+ T cells several identical TCR Vβ CDR3 sequences were identified in different subjects suggesting clonal expansion driven by a common antigen. Abundant IL-17 producing T cells were observed in healthy nasal mucosal and polyp populations with Th17-related genes the most overexpressed compared to peripheral blood T cells. Conclusion: IL-25 and IL-33 may interact locally with IL-17RB+ST2+ polyp T cells to augment Th2 responses in CRSwNP. A local Th17 response may be the default signature in healthy nasal mucosal immune homeostasis. Three biological replicates. T-helper cells were isolated from nasal mucosa by explant culture and from peripheral blood from healthy control subjects. CD4+ve cells were then sorted by flow cytometric sorting. Resting and activated nasal T-helper cells were compared with resting and activated blood T-helper cells.