Soluble Intercellular Adhesion Molecule-1 (sICAM-1) in Patients with Rheumatoid Arthritis and Systemic Lupus Erythematosus

Serum levels of the soluble form of the intercellular adhesion molecule-1 (sICAM-1) have been advocated as a parameter of clinical relevance in determining the activation of the immune system in inflammatory disease(s). We have determined sICAM-1 levels in 46 patients with rheumatoid arthritis (RA), in 53 patients with systemic lupus erythematosus (SLE), and in 82 healthy controls using a commercially available ELISA system. When compared to the healthy controls, sICAM-1 levels of the patients did not differ statistically significantly nor was there any difference between the patient groups. However, there was a strong correlation within the patient groups between sICAM-1 levels and conventional measures of disease activity. Thus, although sICAM-1 may be of theoretical interest with regard to immune activation, our results do not support the view of sICAM-1 providing additional information to the clinical rheumatologist when it is compared to more conventional measures such as acute-phase proteins or clinical activity scores.