The Diagnostic Value of New Additional Antiphospholipid Antibodies in Antiphospholipid Syndrome

BACKGROUNDThe antiphospholipid syndrome (APS) is an autoimmune disease that is characterized by thrombosis and/or pregnancy failure and associated with the presence of all or at least one of three standard antibodies (anti-phospholipid (aPL) antibodies, including lupus anticoagulant (LA), anti-cardiolipin (aCL), and anti-β2-glycoprotein I (anti-β2GPI)). A growing body of evidence recommends adding additional aPL antibodies, such as anti-phosphatidylserine (aPS), anti-prothrombin (aPT), and anti-annexin A5 (aAA5), to conventional laboratory tests (revised Sapporo criteria), especially in seronegative APS cases. OBJECTIVESWe aimed to compare the diagnostic value, utility, and performance of these three additional antibodies along with the standard aPL antibodies in cases with confirmed and non-criteria APS (seronegative). METHODSThis was a prospective observational study on 59 patients who presented with clinical features of APS at the hematology, medical, rheumatology, and obstetric clinics. LA was detected by standard coagulation tests, while other aPL, IgG, and IgM antibodies (aCL, aβ2GPI, aPS, aPT, aAA5) were detected with enzyme-linked immunosorbent assay (ELISA). RESULTSAnti-PS antibody was more frequent compared to aPT and aAA5 in both confirmed cases (84.6%) and non-criteria (seronegative) (15.4%) APS. As a single test, the aPS antibody was significantly better (P