Electron microscopical studies of the cell population in nasal secretions.

The purpose of this study is to identify the cell types and ultrastructural changes of the cells in nasal secretions, and to understand the pathology of allergic and infectious rhinitis. Nasal secretions from 20 patients with allergic rhinitis and 15 patients with infectious rhinitis have been observed by transmission electron microscopy. The cell population of the allergic group consists of (in order of predominance): epithelial cells, eosinophils, neutrophils, lymphocytes, basophilic cells (basophil leukocytes and mast cells), and macrophages. In the infectious group the population contains: neutrophils, epithelial cells, macrophages, and lymphocytes. Marked degranulation has been observed in the granules of eosinophils in allergic nasal secretions together with granule fusion, vacuolation, and signs of phagocytosis. Increased numbers of basophil leukocytes and mast cells are also a feature of the allergic nasal secretion. Degranulation of neutrophils is markedly increased in the infectious group as compared to the allergic group. Clustered epithelial cells are observed in the allergic group more often than in the infectious group. Four types of lymphocytes with different morphological features are observed in both groups, i.e. small lymphocyte, T-lymphocyte-like cells, large granular lymphocyte-like cells, and plasma cells. The results of the present study show special ultrastructural characteristics in the cell population of allergic nasal secretions, i.e., an increase in the number of degranulated eosinophils and basophilic cells, clustered epithelial cells, and large granular lymphocytes, while an increase in degranulated neutrophils and macrophages with marked phagocytosis are characteristic for infectious nasal secretions.