Disease Distribution of β2-Glycoprotein I-Dependent Anticardiolipin Antibodies in Rheumatic Diseases

Abstract
We investigated the clinical significance of IgG β2-glycoprotein I (GPI)-dependent anticardiolipin antibodies (aCL) in rheumatic diseases. Three hundred and seventeen patients were entered. They consisted of 133 patients with SLE, 60 with RA, 45 with SSc, 37 with PM, 23 with overlap syndrome (overlap), and 19 with unclassified connective tissue disease (UCTD). IgG β2-GPI-dependent aCL were examined by ELISA. While IgG β2-GPI-dependent aCL were detected in 13% of patients with SLE, these aCL were positive in two patients with SSc, two with overlap and 14 with UCTD. A significant association between IgG β2-GPI-dependent aCL and thrombosis was found. Clinical manifestations were studied in 32 patients with secondary APS based on SLE and 14 with primary APS (PAPS). Incidences of malar rash, arthritis, renal disorder, leucopenia, immunological disorders and hypocomplementemia were significantly less frequent in patients with PAPS. IgG β2-GPI-dependent aCL were detected in all patients with PAPS and in 34% of secondary APS. This difference was significant. These data suggest that IgG β2-dependent aCL are useful for identifying a subset in patients with APS.