Circulating soluble ICAM-1 (sICAM-1) isoforms are known to be elevated in inflammatory and autoimmune disorders (SLE, RA). A correlation between levels of circulating sICAM-1 and disease activity was described (5). In sera from 31 patients suffering from histologically confirmed Wegener's granulomatosis (WG) elevated levels of ICAM-1 were now detected in this primary systemic vasculitis. In generalized active disease circulating ICAM-1 levels were significantly higher when compared to remission and healthy control individuals. Sera from WG patients collected during intercurrent infections while on immunosuppressive drugs showed no elevation of circulating ICAM-1.