A rapid semiautomatical enzyme linked immunoassay identifying intercellular adhesion molecule-1 (ICAM-1) on the...

Intercellular adhesion molecule-1 (ICAM-1), a member of the immunoglobulin gene superfamily, is a cytokine-inducible adhesion molecule, which plays a central role in leukocyte migration into sites of acute or chronic inflammation. In this article we describe a sandwich immunoenzymometric method which allows rapid, semiquantitative (in "enzyme immunoassay units", EU) identification of ICAM-1 on the surface of alveolar macrophages. We evaluated this method in two groups of patients with pulmonary sarcoidosis (n = 12) or bacterial pneumonia (n = 11) and a group of healthy volunteers (n = 6), comparing the results with those obtained by immunocytochemical staining. ICAM-1 expression on the sarcoid alveolar macrophages surface was significantly elevated, as compared with control alveolar macrophages (0.76 EU +/- 0.27 vs. 0.44 EU +/- 0.12, p < 0.01). ICAM-1 expression on the surface of alveolar macrophages from patients with pneumonia was not elevated (0.48 EU +/- 0.35). Stimulation with tumour necrosis factor-alpha (TNF-alpha) or interferon-gamma (100 kU/l) led to a significant induction of ICAM-1 on the surface of control alveolar macrophages (0.76 EU +/- 0.18, p < 0.005 for TNF-alpha, 0.64 EU +/- 0.10, p < 0.005 for interferon-gamma), whereas alveolar macrophages from both patient groups did not respond to cytokines even at high dosages. ICAM-1 expression on the surface of alveolar macrophages from patients with sarcoidosis correlated with the spontaneous release of TNF-alpha by macrophages (R = 0.77, p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)