Study of Eosinophil Activation in Nasal Mucosa in Patients with Perennial Nasal Allergy: Effects of CO 2 Laser Surgery

Carbon dioxide (CO₂) laser surgery has been shown to be clinically effective in the treatment of nasal allergy. To investigate the mechanisms of eosinophil infiltration and activation underlying the therapeutic effects of CO₂ laser surgery, we examined changes in the cytological profile of nasal mucosa after surgery. Twenty-two patients with perennial nasal allergy against house-dust mites underwent two or three rounds of laser surgery at 1-month intervals on an outpatient basis. The following parameters were evaluated at each visit: (i) improvement of clinical symptoms (nasal obstruction, rhinorrhea, and sneezing), (ii) percentage of infiltrating eosinophils in nasal mucosa, and (iii) the degree of EG2⁺ cells and intracellular adhesion molecule 1 (ICAM-1) expression by immunocyto-chemistry. All clinical symptoms significantly decreased after surgery. Significant reductions in eosinophil infiltration (p < 0.01) and the percentage of EG2⁺ cells (p < .005) were observed also. However, the degree of ICAM-1 expression in epithelial cells was not changed. These results suggest that CO₂ laser surgery partially reduced the allergic reactions, leading to improvement of clinical symptoms.