Circulating soluble intercellular adhesion molecule-1 (sICAM-1) in patients with sarcoidosis

sICAM-1 has been elevated in sera of specific inflammatory diseases, and circulating sICAM-1 concentrations reflect disease activity in these diseases. We measured circulating sICAM-1 concentrations and serum angiotensin-converting enzyme (SACE) activity in patients with sarcoidosis. Patients with sarcoidosis had significantly increased circulating sICAM-1 concentrations (62.8±33.5U/ml) and SACE activity (23.7±7.4U/l) compared with controls (circulating sICAM-1 50.9±12.1U/ml, and SACE 13.5±3.8U/l). Successive measurements showed that circulating sICAM-1 values changed in parallel with disease activity in sarcoidosis. In the progressive disease group (progressed or without change for 2 years or more), circulating sICAM-1 values (102.2±35.3U/ml) at the time of diagnosis were significantly increased compared with those in the regressive disease group (disappeared or regressed within 2 years) (46.4±12.6U/ml). However, there was no significant difference in SACE activity of the regressive and progressive disease groups. Fifteen patients with a high value of circulating sICAM-1 (>75U/ml, mean of controls+2s.d.) all had progressive disease, while only 15 of 44 patients with a high value of SACE had progressive disease. Circulating sICAM-1 will be a useful blood marker to predict outcome and to monitor disease activity in sarcoidosis.