The cause of severe nasal polyposis in AERD is unknown. To understand the role of antibody-secreting cells in AERD, Buchheit et al. studied these cells in nasal polyps. They noted that polyp IgE and IgG4 levels were elevated in subjects with AERD compared with aspirin-tolerant subjects with nasal polyposis – those with higher tissue IgE levels had more rapid nasal polyp recurrence. Plasma cells in the nasal polyps of AERD also had a higher surface expression of IL-5Rα compared to aspirin-tolerant subjects, and IL-5 stimulation of nasal polyp plasma cells from subjects with AERD induced changes in a distinct set of genes. These findings suggest a role for IL-5Rα+ antibody-secreting cells in producing antibodies within the sinus tissue and perhaps contributing to the severe nasal polyposis in patients with AERD.