Plasma thrombomodulin as an indicator of thromboembolic disease in systemic lupus erythematosus

We serially measured the plasma thrombomodulin (TM) levels in systemic lupus erythematosus (SLE) patients and assessed them clinically. The patients who responded to medical treatment experienced a decrease in plasma TM levels. Patients who developed exacerbations of SLE, thrombotic thrombocytopenic purpura or thrombosis, displayed increased plasma TM levels. There was no significant difference between the plasma TM levels of the lupus anticoagulant-positive (LAC-positive) patients and the LAC-negative patients or between the plasma TM levels of the anticardiolipin antibody-positive (aCL-positive) patients and the aCL-negative patients. While LAC and aCL titers did not always coincide with improvement in the patients' clinical course or with aggravation of the disease, the TM values correlated well with the patients' clinical condition. Plasma TM values may be used to evaluate disease activity and may predict the occurrence of thrombosis in SLE.