PHENOTYPIC FEATURES AND ACTIVATION OF ALVEOLAR MACROPHAGES IN ATOPIC ASTHMATIC PATIENTS

Cells of mononuclear phagocyte system exhibit a wide range of surface antigen receptors. These receptors can be broadly divided into those with "immune and non-immune" functions. The expression of immune receptors briefly increases with maturation of the cell, indicating higher levels of the surface Fc Or (CD23), can contribute to the type 1 hypersensitivity reaction which occur in allergic asthma. In addition to immune receptors, the cells of the mononuclear phagocyte system exhibit a wide variety of the other receptors indicating their diverse role in bronchial phlogosis, such as cell homing receptor (CD44). The aims of this study have been to comparatively evaluate, in four normal subjects (age = x±sd = 35.2±3.86) and in eight atopic patients with mild asthma in intercritical phase (FEVj! x±sd = 91.2±13.3) and with bronchial hyperresponsiveness (PD20 FEVji x±sd = 377±68 meg methacholine), the alveolar macrophage phenotype and activation features studied by flow cytometry. In the asthmatic patients a large number of cells of the monocyte-macrophage series expressing the phenotypic pattern of macrophages (as shown by means of the specific monocyte macrophage differentiation markers CD 14 and CD33) was recovered by bronchoalveolar lavage (BAL), in comparison with control subjects. Most of these cells displayed an increased expression of the HLA-DR molecule and of the low affinity receptors Fc Hr (CD23) as shown by means of the analysis of fluorescence intensity curve obtained from Kolmogorov-Smimov statistic test indicating 99% probability of difference between controls and patients. Moreover, the same cells expressed CD54, the intercellular adhesion molecule (ICAM-1) which is a ligand for the lymphocyte function associated antigen-1 (LFA-1), thus suggesting a possible enhanced cooperation between lymphocytes and macrophages. Finally, AM from asthmatic patients exhibited an increased expression of CD44, a homing receptor, involved via interactions with collagen and fibronectin, in the macrophage migration from peripheral blood to other tissues