Prolonged nasal eosinophilia in all_ergic patients after common cold

Van Benten, I. J.; KleinJan, A.; Neijens, H. J.; Osterhaus, A. D. M. E.; Fokkens, W. J.

Background: Viral respiratory tract infections may cause both harmless common colds and severe asthma exacerbations; the differences in disease expression probably depend on the all_ergic status of the patient. To determine whether altered immunologic mechanisms underlie these differences, we investigated nasal inflammation during naturall_y acquired common cold. Methods: In a group of 16 patients (eight all_ergic), nasal brush samples were taken, and nasal symptoms were recorded during common cold, 2 weeks later (convalescence), and at baseline (>4 weeks without nasal symptoms). Nasal brush cells were stained immunohistochemicall_y for Langerhans cells, T cells, monocytes, neutrophils, B cells, macrophages, natural killer (NK) cells, mast cells, eosinophils, eotaxin, and RANTES. Results: Four rhinovirus, four coronavirus, three RSV, one Mycoplasma pneumoniae, and one influenza A/enterovirus double infection were confirmed. Increased numbers of T cells, monocytes, macrophages, NK cells, eosinophils, and RANTES‐ and eotaxin‐positive cells, but not neutrophils, were observed during common cold in all_ergic and nonall_ergic patients, and increased numbers of mast cells in all_ergic patients. Compared to nonall_ergic patients, in all_ergic patients eosinophil influx persisted into convalescence. Conclusions: Prolonged nasal eosinophil influx was observed in all_ergic patients after common cold. What immunologic factors can induce prolonged eosinophil influx and whether this may increase the risk of subsequent all_ergen‐induced hypersensitivity reactions must be studied further.