IL-5Rα marks nasal polyp IgG4 and IgE-secreting cells in aspirin-exacerbated respiratory disease

Background: The cause of nasal polyposis in aspirin-exacerbated respiratory disease (AERD) is unknown. Elevated antibody levels have been associated with disease severity in nasal polyps, but the upstream drivers and cellular mechanisms of local antibody production in AERD remain to be investigated. Objective: We sought to identify the upstream drivers and phenotypic properties of local antibody-secreting cells in nasal polyps and to understand their clinical relevance in AERD.Methods: Sinus tissue was obtained from subjects with AERD, aspirin-tolerant chronic rhinosinusitis with nasal polyps (CRSwNP), aspirin-tolerant chronic rhinosinusitis without nasal polyps (CRSsNP), and healthy controls. Tissue antibody levels were quantified via ELISA and immunohistochemistry, and were correlated with clinical markers of disease severity. Tissue cytokine mRNA levels were measured with quantitative PCR (qPCR). Antibody-secreting cells were profiled with a combination of single-cell RNA-sequencing (scRNA-seq), flow cytometry and immunofluorescence.Results: Tissue IgE and IgG4 were elevated in AERD compared to controls (pu003c0.01 for IgE and pu003c0.001 for IgG4, vs. CRSwNP). Total IgG and IgG4 positively correlated with the number of polyp surgeries per subject (r=0.48, p=0.011 and r=0.58, p=0.0003, respectively). Polyp IL-10 mRNA expression was higher in AERD vs. CRSwNP (pu003c0.05), but there were no differences in mRNA expression of type 2 cytokines. ScRNA-seq revealed increased IL5RA, IGHG4, and IGHE in the antibody-associated cells of subjects with AERD compared to CRSwNP. Total plasma cells and IL-5Rα+ plasma cell numbers in the polyp tissue from AERD exceeded those in polyps from CRSwNP (p=0.0051 and p=0.026, respectively) by flow cytometry. With immunofluorescence, we determined that IL-5Rα and IgG4 are co-expressed in antibody-secreting cells in AERD.Conclusions: Our study identifies unique clusters of antibody-secreting cells in AERD defined by enrichment of transcripts encoding IL5RA, IGHG4 and IGHE. We confirm surface expression of IL-5α on these cells, and identify T cells as a unique transcriptional source of IL-5. Tissue antibody levels are elevated in AERD and correlate with disease severity. Our findings suggest a role for IL-5 in facilitating local antibody production that may drive features of severe sinus disease.