Inflammatory cells in nasal mucosa and nasal polyps

Since some controversy exists concerning the frequency of inflammatory cells in nasal polyps, we have compared the frequency of tissue inflammatory cells (lymphocytes, neutrophils, eosinophils and plasma cells) including 11 kinds of lymphocyte subsets in the same specimens of nasal mucosa and nasal polyps.

Histopathological observations and flow cytometric analyses were performed on eight mucosal specimens of the inferior turbinates of patients with nasal polyps and on 13 polyp specimens.

Nasal polyps contained significantly more eosinophils, neutrophils and plasma cells than nasal mucosa, and EG2+ cells (activated eosinophils) were significantly more frequent in nasal polyps than in nasal mucosa. Flow cytometric analysis showed that there were no significant differences in the frequencies of lymphocytes and lymphocyte subsets (CD1+, CD2+, CD3+, CD5+, CD7+, CD4+, CD8+, CD10+, CD19+, CD20+ and HLA-DR+ cells) including CD4/8 ratios between nasal mucosa and polyps, though, both nasal mucosa and polyps contained significantly more lymphocytes than eosinophils, neutrophils or plasma cells. The T cell lineage (CD2+, CD3+, CD5+ and CD7+ cells) was found in high frequency and B cell lineage (CD10+, CD19+ and CD20+ cells) in low frequency in both nasal mucosa and polyps. The frequency of HLA-DR+ cells (most of which were activated T cells) was not significantly different between nasal mucosa and nasal polyps.

Histopathological and flow cytometric analyses were performed on the composition of inflammatory cells in nasal mucosa of the inferior turbinates and in polyps from the same patients. The elevated numbers of activated eosinophils, neutrophils and plasma cells in nasal polyps compared with nasal mucosa suggest that inflammatory processes play important roles in the pathophysiology of nasal polyps. The frequencies of lymphocytes and lymphocyte subsets were not significantly different between these two tissues.