GLOBULE LEUCOCYTES: AN ULTRASTRUCTURAL ANALYSIS OF THE HUMAN INTRAPULMONARY AIRWAYS IN C.O.P.D. PATIENTS AND NORMAL SUBJECTS

In the current study we describe the presence and the ultrastructure of globule leucocytes (GL) in the respiratory epithelium of the lobar bronchi of eight adult individuals (1 normal, plus 7 C.O.P.D.). This peculiar type of migratory cell was previously described in rat trachea (Kent, 1966; Jeffery and Reid, 1975), in dog bronchial epithelium (Frasca et al., 1968), in calf bronchoalveolar lavage (Coles et al., 1987) and human upper respiratory tract (Baert and Frederix, 1985). We are therefore the first who describe the presence of GL in the bronchial mucosa of the human lower respiratory tract. The T.E.M. analysis of mucosal bioptic specimens obtained through fiberoptic bronchoschopy from the human intrapulmonary bronchial epithelium revealed the presence of cells characterized by intracytoplasmic granules showing a homo¬geneous electrondense matrix, nevertheless considerably variable in size, shape and number. According to such peculiar morphological features, these cellular elements were classified as GL. The origin of these cells in the airway epithelium is uncertain, but the presence of granulated cells both in the basal layer of the epithelium, in the subepithelial connective tissue and in the submucosal blood vessels, suggest that GL may result from the possible transformation-maturation of granulated leucocytes. The current, morphological, study is the starting point for next studies on GL possible role and involvement both in the physiology and physiopathology of the human respiratory function.