ANTIPHOSPHOLIPID ANTIBODIES (APL) INCREASE THE POTENTIAL MONOCYTE PROCOAGULANT ACTIVITY IN PATIENTS WITH SYSTEMIC LUPUS-ERYTHEMATOSUS

Lupus anticoagulant (LA) and anticardiolipin antibodies (aCL) are freq uently detected in sera from patients affected by systemic lupus eryth ematosus (SLE). However, the role of antiphospholipid antibodies (aPL) in thrombus formation has not been defined as yet. Twenty-two patient s affected by SLE, all fulfilling the 1982 ARA revised criteria, and t wenty healthy subjects were investigated for the presence of LA, aCL a nd other aPLs. Monocyte procoagulant activity-PCA (Tissue Factor produ ction) was evaluated by one stage plasma recalcification time. In all patients the plasma levels of F1 + 2 and of plasminogen activator inhi bitor (PAI) were also determined. Monocyte PCA was significantly highe r in SLE patients with LA and/or aCL in comparison to SLE patients wit hout LA and/or aCL (p < 0.01) and to controls (p < 0.05). However, no connection was observed between PCA expression by mononuclear cells an d LA or aCL levels. No differences in F1 + 2 and PAI plasma levels wer e found between SLE patients with or without aPL and controls. In our SLE patients LA and/or aCL positivity appears strictly related to an i ncreased monocyte activation that could play an important role in the occurrence of thrombotic events.