Negative Antiphospholipid Syndrome: a Multicentric Study
Multicentre no-profit, national, (cross-sectional diagnostic) retrospective study, promoted by the Italian Society for Rheumatology. The main objective of the study is to assess the diagnostic accuracy of non-criteria aPL (anti-vimentin/cardiolipin and anti-phosphatidylserine/prothrombin) in identifying APS in patients with thrombosis/recurrent adverse pregnancy outcomes.
• Group 1 \[APS\]: Patients fulfilling the classification criteria for antiphospholipid syndrome (seropositive APS, SP-APS)
• Group 2 \[SN-APS\]: patients with seronegative APS (SN-APS): with clinical criteria (thrombotic or obstetric) for APS, persistently negative for aPL, and with clinical features highly suggestive of APS (recurrent events, thrombotic + obstetrical events, extra-criteria manifestations, other autoimmune diseases)
• Group 3: patients with clinical criteria (thrombotic or obstetric) for APS, negative for aPL, but without clinical features highly suggestive of APS (recurrent events, thrombotic + obstetrical events, extra-criteria manifestations, other autoimmune diseases).
• Age \< 65 years (at event time)
• Less than 5 years from the first even