Antiphospholipid antibodies in the connective tissue diseases: their relation to the antiphospholipid syndrome and forme fruste disease.

Anticardiolipin antibodies (aCL) were measured in the sera of patients with different connective tissue diseases and spondyloarthropathies. Elevated antibody binding was found in systemic lupus erythematosus (SLE), rheumatoid arthritis, scleroderma, primary sicca syndrome, dermatopolymyositis and psoriatic arthritis but not in ankylosing spondylitis. The 15 highest binding SLE patients included 10 with Raynaud's phenomenon, 5 with livedo reticularis, 7 with vasculitis, 3 with major thrombotic episodes and 3 with spontaneous abortions. aCL were also measured in patients with these clinical features in isolation. Seven of 18 patients with multiple thromboses and 3/22 with multiple spontaneous abortions had raised aCL binding. Normal or near normal levels were found in patients with idiopathic thrombocytopenia, livedo reticularis, a single cerebral thrombosis and uncomplicated myocardial infarction.