ICAM-1 expression on alveolar macrophages and in serum of sarcoidosis patients

The intercellular adhesion molecule-1 (ICAM-1) is important in mediating intercellular contact in inflammation. Therefore, we have analyzed the expression of this molecule on alveolar macrophages (AM) and in serum of patients with sarcoidosis. Bronchoalveolar lavage (BAL) cells from 13 patients and 11 control donors were stained with an anti ICAM-1 monoclonal antibody (mAb) or an isotype control. Alkaline phosphatase was used as a detection system, followed by digital single cell image analysis. Soluble ICAM-1 in serum (ssICAM-1) was determined by enzyme linked immunoassay (Elisa). Immunocytochemistry revealed a strong increase of ICAM-1 expression on AM from sarcoidosis patients (64%) compared to healthy controls (30%). Furthermore, patients exhibited a fourfold higher antigen density. Serum levels of sICAM-1 were more than twofold increased in the patient group (805.4 micrograms/ml) compared to healthy controls (384.8 micrograms/ml). SsICAM-1 showed an inverse correlation with vital capacity (VC) and diffusing capacity (DCO). This significant correlation with impairment of two important lung function parameters suggests that ssICAM-1 might be useful in serological assessment of disease activity in sarcoidosis.