The authors examined, using a new method of the ELISA test for assessment of antibodies against beta2 glycoprotein I (b2-GPI), 142 serum samples from patients with various diffuse connective tissue diseases. 72 samples were continuously collected from patients with SLE or some clinical or laboratory manifestations of the antiphospholipid syndrome. Other serum samples came from a serum bank of an immunological laboratory. Thirty cases of SLE were involved, 20 cases of systemic scleroderma and 20 cases of polymyositis/dermatomyositis. All sera were also examined for the presence of anticardiolipin antibodies (aCL). The results of the two methods were compared. A considerable degree of correlation of results of the two tests was found. However, several different results indicate that by the test for anti-b2 glycoprotein antibodies other members of the group of heterogeneous antiphospholipid antibodies can be detected. In particular for establishment of the diagnosis of antiphospholipid syndrome (APS) it is useful to assess in addition to the lupus anticoagulans (LA) and anticardiolipin antibodies also antibodies against b2-glycoprotein I.

        Key words: antiphospholipid syndrome, anticardiolipin antibodies, antibodies against beta2-gly- coprotein I