Comparative Study between New Novel Biomarker Antiphosphatidylserine/prothrombin Antibodies and Conventional Established Diagnostic Markers in the Lab Diagnosis of Antiphospholipid Syndrome

Background: Ant phosphatidylserine/prothrombin complex (aPS/PT) antibodies are emerging as an important marker in the lab diagnosis antiphospholipid syndrome (APS).We aimed to compare performance of new novel marker aPS/PT antibody with that of conventional antiphospholipid antibodies (aPL) such as lupus anticoagulant (LA), anticardiolipin (aCL), and anti-2-glycoprotein I (anti-2GPI) in suspected APS patients.In this study we aimed to find the percentage of cases positive for aPS/PT antibodies in cases with bad obstetric history who had one or more antiphospholipid antibody positivity needed for diagnosis of APS.We further compared IgG and IgM component of aPS/PT with IgG and IgM components of aCL and anti-2GP 1. Also,Cases which were positive for LA was also tested for aPS/PT to find the correlation.Methods: Total 100 samples (registered for BOH panel) who fulfilled the lab criteria for diagnosis of APS were included in the study.IgG/IgM aCL, IgG/IgM anti-2GPI and IgG/IgM aPS/PT were detected in serum using ELISA assay in Quantalyser 3000 (Inova, San Diego, CA, USA).Lupus Anticoagulant was detected using Star Max (Diagnostica Stago, France).The two different coagulation tests used to detect Lupus anticoagulant (LA) were PTT-LA and dRVVT.Results: Among 100 patients who fulfilled the lab criteria of APS having BOH included in our study showed 65% positivity for aPS/PT IgG/IgM.Both IgG aPS/PT and aPS/PT IgM were seen in 60 cases out of 65.Significant association were found on comparing the presence of aPS/ PT IgG with Cardiolipin IgG and aPS /PT IgM with Cardiolipin IgM ie 85% and 95% respectively Also association was seen on comparing the presence of aPS/ PT IgM with Beta 2 glycoprotein IgM ie.57% and significant correlation with Beta 2 Glycoprotein IgG ie 85%.Out of 8 cases with LA positive result, 7(87.5%) were positive for aPS/PT, hence showing highly significant association. Conclusion:aPS/PT antibody is closely associated with conventional antibodies of APS including LA.The determination of aPS/PT in clinical practice, in conjunction with that of other aPL, may improve the likelihood lab diagnosis of APS.