Intercellular adhesion molecule-1 in patients with idiopathic interstitialpneumonia

This study focuses on a possible role of intercellular adhesion molecule-1 (ICAM-1) in interstitial pulmonary diseases. We determined a soluble form o f ICAM-1 in serum and bronchoalveolar lavage fluid (BALF) using ELISA in pa tients with usual interstitial pneumonia (UIP), bronchiolitis obliterance o rganizing pneumonia (BOOP), or nonspecific interstitial pneumonia (NSIP). I n addition, we investigated the expression of ICAM-1 in the lung tissues of these patients by means of immunohistochemical staining. Serum levels of s oluble ICAM-1 were significantly higher in patients with UIP or NSIP than i n healthy subjects, and were also high in patients with BOOP. The soluble I CAM-1 in BALF tended to be higher in patients with UIP, BOOP, or NSIP than in normal subjects. A significant correlation was seen between soluble leve ls of ICAM-1 in serum and BALF. In the immunostaining of ICAM-1 of the lung tissues, ICAM-1 expression was more pronounced in patients with UIP than i n those with BOOP or NSIP. The increased expression of ICAM-1 was seen in t ype II alveolar epithelium and vascular endothelium in patients with inters titial pneumonia. A positive correlation was observed between the degree of ICAM-1 expression in the lung tissues and the BALF levels of soluble ICAM- 1. The expression of ICAM-1 in type II alveolar epithelium suggests that IC AM-1 plays a specific role in the fibrotic process of the lung, and that th e measurement of soluble ICAM-1 in sera and BALF could be a useful marker f or evaluating the progression of fibrosis.