Prevalence of aPhosphatidylserine/prothrombin antibodies and association with antiphospholipid antibody profiles in patients with antiphospholipid syndrome: A systematic review and meta-analysis

Antiphospholipid syndrome (APS) is an autoimmune disorder characterized by the presence of antiphospholipid antibodies (aPLs) and thrombotic events. The association of aPLs with thrombotic events depends on the number of positive tests. Besides the three classical tests to classify APS, phosphatidylserine/prothrombin complex autoantibodies (aPS/PT) are increasingly used to better define this condition. The aim of this systematic review was to evaluate the prevalence of aPS/PT in general and according to antiphospholipid antibody profiles in patients with APS.A systematic search of PubMed, Web of Science, and the Cochrane Library from January 1990 to September 2021 was carried out according to PRISMA guidelines. Proportions and 95% confidence intervals (CIs) were calculated using random-effects model. Publication biases were evaluated via visualization of funnel plots along with Egger's and Begg's tests.Twenty-one articles about the prevalence of aPS/PT in 1853 patients with APS were deemed eligible and analyzed according to the inclusion criteria. Pooled prevalence of aPS/PT IgG alone, IgM alone, and IgG/M were 50.0%, 45.0%, and 65.0%, respectively. No significant publication bias was detected from funnel plots or Egger's and Begg's tests. When the prevalence of aPS/PT was calculated in homogeneous aPLs, a much higher rate of pooled prevalence of aPS/PT IgG/M in patients positive for Lupus Anticoagulant (84.5%) and in those with triple positivity (83.4%) was found.These data show a high rate of aPS/PT positivity in patients with APS (especially in those positive for LAC) but further studies are needed to ascertain whether this test might be useful in the laboratory classification criteria of APS.