Value of ICAM-1 Expression and Soluble ICAM-1 Level as a Marker of Activity in Sarcoidosis

Background: The natural course of sarcoidosis is variable, but no single parameter has been generally accepted as a good marker for disease activity. Adhesion molecules are required for the migration of inflammatory cells; thus, they may be markers of activity in sarcoidosis. Methods: In 16 patients with active sarcoidosis and 11 with inactive disease (10 were male, 17 were female; mean age [6 SD], 39.6 6 11.0 years; mean follow-up, 21 6 16 months), the expression of adhesion molecules on cells obtained with BAL (measured by flow cytometry) and the level of soluble intercellular adhesion molecule 1 (sICAM-1) in the serum and BAL fluid (BALF) were measured at the time of diagnosis and during the follow-up. The changes in serum sICAM-1 level and ICAM-1 expression on cells obtained with BAL were compared with the clinical course of the disease. Results: In patients with active disease, the ICAM-1 on alveolar macrophage (AM) (relative linear median fluorescence intensity [RMFI], 3.21 6 1.55) and sICAM-1 levels in serum (575 6 221 ng/mL) and BALF (47.3 6 19.3 ng/mL) were higher than those for patients with inactive disease (RMFI, 1.67 6 0.66; p 5 0.0034; serum, 263 6 98.5 ng/mL; p 5 0.0001; BALF, 27.5 6 19.0 ng/mL; p 5 0.0209). In the patients with active disease, ICAM-1 on AM and serum sICAM-1 decreased (RMFI, 1.51 6 0.84; 284 6 118 ng/mL, respectively) after steroid therapy, but no significant change was noted in patients with inactive disease. We also found that the initial ICAM-1 on AM and serum sICAM-1 had a significant correlation with the degree of improvement in pulmonary function tests after the therapy. The disease relapsed in four patients after the discontinuation of steroids, and the serum sICAM-1 level was elevated again at the time of relapse. Conclusion: Our data suggest that the serum sICAM-1 level and the ICAM-1 expression on AM may be good markers of disease activity and also a predictor of outcome in sarcoidosis. (CHEST 1999; 115:1059 ‐1065)