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Abstract
Background and aims To explore utility of Antibodies to Phosphatidylserine/Prothrombin Complex (aPSPT), in Indian Anti phospholipid Syndrome (APS) patients.
Methods Data of 372 subjects whose sera was tested for aPSPT by ELISA (AESUKU,GERMANY), was retrospectively analysed. Performance of various APLs was compared using non-parametric tests. To ascertain additional utility of aPSPT, patients with suspected APS were categorised into 2 groups i.e. i) those with any one of criteria antibodies positive ii) those with any one APL positivity including anti- PSPT positivity.
Results In 46 patients of APS, 38 (82.60%) had thrombotic events (21 arterial , 26 venous) and 11 ( 23.91%) had obstetric events. Lupus anticoagulant was present in 37/46 (80.43%) ,anticardiolipin antibody in 19/46 (41.33%), aPSPT in 17/46 (36.95%), anti-β2glycoprotein1 (β2GP1) IgG and IgM in 13/46 (28.26%) and 7/46 (15.21%) patients of APS respectively. aPSPT tested positive in 9/60 (15%) patients with seronegative APS (SNAPS). aPSPT did not differ from other criteria APLs in any clinical parameter except compared to those with IgM B2GP-1 positivity. aPSPT was numerically more sensitive and specific than IgM B2GP1 for thrombotic, non-criteria events but less sensitive for detecting obstetric events (Table 2). Inclusion of aPSPT test in patients with suspected APS increased sensitivity marginally but with concomitant decrease in specificity.
Showing the categorization of Study subjects into patients and controls.
Comparision of sensitivity and specificity of aPSPT and IgM anti-β2GP1 in definite APS patients.
Conclusions In our study, aPSPT was third most common antibody in APS patients, displaying higher sensitivity and specificity in comparison to IgM anti-β2 GP1 for all APS manifestations except obstetric ones. SNAPS patients may test positive for aPSPT, thus endorsing its inclusion in classification criteria of APS.