PLATELET-DERIVED GROWTH-FACTOR IN ASTHMA

Platelet-derived growth factor (PDGF) controls cellular growth, migrat ion, and differentiation. It is secreted by various cell types, includ ing macrophages, and participates in tissue repair and epithelial rege neration. PDGF may therefore be involved in airway remodeling in asthm a. This study compared the immunoreactivity of PDGF and its receptors (R alpha and R beta) in bronchial biopsies and the levels of PDGF in b ronchoalveolar lavage (BAL) fluid of asthmatics and control subjects. Bronchial biopsies were done in a subsegmental bronchus of 11 asthmati cs and 11 control subjects by flexible bronchoscope. PDGF AA and BE, a nd PDGF receptors Rr and RP were studied with monoclonal antibodies an d revealed by immunoperoxidase staining. The percentage of subjects pr esenting positive staining with PDGFs and its receptors was studied in the epithelium and submucosa. PDGF AA, AB, and BB were measured in BA L fluid of 18 asthmatics and 10 controls by specific ELISA. In biopsie s, there was no significant difference between asthmatics and controls for PDGF AA, BB, PDGF-R alpha and R beta (Fisher's exact test and Bon ferroni's correction). Moreover, the levels of PDGF, AA, AB, and BB we re similar in asthmatics and controls. This study does not support a r ole for PDGF in the repair processes of asthma.