ASSOCIATION BETWEEN IGM ANTICARDIOLIPIN ANTIBODIES AND DEEP VENOUS THROMBOSIS IN PATIENTS WITHOUT SYSTEMIC LUPUS-ERYTHEMATOSUS

Patients with systemic lupus erythematosus (SLE) are at risk of develo ping deep venous thrombosis (DVT). Should anticardiolipin antibodies ( aCL) be detectable, this risk is significantly raised, particularly wh en these autoanti-bodies are cofactor-dependent. We conducted a cross- sectional study of consecutive unselected outpatients referred for cli nical suspicion of DVT, as an attempt to address the following questio ns: firstly, were aCL antibodies associated with DVT in non-SLE patien ts? Secondly, was this association related to the cofactor dependence? From March 1992 to February 1994, 208 patients were enrolled in the s tudy. Venography was positive in 110 patients (DVT patients), while th e diagnosis of DVT could not be confirmed in the remaining 98 (referre d to as disease controls). ACL was measured by ELISA, for IgG and IgM isotypes in two ways: fetal calf serum or bovine serum albumin were us ed as blocking agents to distinguish between cofactor-dependent and co factor-independent antibodies. Positive aCL was defined as optical den sity (OD) values greater than the 95th percentile of OD distribution o f 60 healthy controls. We found a high frequency of positive IgG aCL a ntibodies in both DVT patients and in disease controls (25.5 vs 23.5%) . We suggest an association between IgM aCL and DVT. This association was, however, not dependent on the cofactor requirement.