[Type II alveolocyte--a subsidiary cell of the pulmonary immune response]

Distribution of secretory immunoglobulin A has been studied by means of a direct and indirect immunohistochemical reactions in semithin and ultrathin slices, using operative and biopsy material of the human respiratory part of the lungs. The data obtained prove existence of 2 types of cells, which possess properties of subsidiary immune cells. They include alveolar macrophages and alveolocytes of II type. The latter participate actively in the immune pulmonary response, since they possess a property to deposit secretory immunoglobulin A in their cytoplasm. Under conditions of a chronic inflammation amount of II type alveolocytes actively binding immunoglobulin A decreases. A suggestion is made that the local immunity in alveoli decreases and is the cause, resulting very often in transition of nonspecific pulmonary diseases into chronic forms.