ANTIPHOSPHOLIPID ANTIBODIES (APL) IN SYSTEMIC LUPUS-ERYTHEMATOSUS - ARE THEY SPECIFIC TOOLS FOR THE DIAGNOSIS OF APL SYNDROME

Objective-Antiphospholipid antibody (aPL) specificity for aPL-related events was evaluated in systemic lupus erythematosus (SLE). Methods-A study was carried out on 105 patients affected with SLE comparing the prevalence of lupus anticoagulant (LA) and IgG and IgM anticardiolipin antibodies (aCL) between patients with and without features of antiph ospholipid syndrome (APS). Antiphospholipid antibody profile was subse quently evaluated in the aPL positive patients with and without aPL-re lated events, thus excluding the patients with complications of APS po ssibly due to factors other than aPL. Results-LA showed a strong assoc iation with thrombosis and livedo reticularis, and IgG aCL with thromb osis and neurological disorders, while no clinical features were assoc iated with IgM aCL. A considerable number of aPL positive patients wit h no aPL-related manifestations was also observed, suggesting the low specificity of aPL assays (54.4%). When studying the 60 aPL positive p atients, LA was specific (91.3%) for the diagnosis of aPL-related thro mbosis, whereas aCL were not specific, although IgG aCL mean levels we re higher in patients with arterial thrombosis than in those without A PS features. Conclusions-LA but not aCL positivity is a specific tool for the diagnosis of thrombotic complications due to aPL in SLE.