ACLY and systemic lupus erythematosus: Alarcon-Segovia found a decrease in aCL titres in four patients after a thrombotic event in patients with SLE and APS.33 Our study showed that loss of aPL positivity post-thrombosis occurred in 94% for aCL IgM, 94% for aCL IgG, 75% for aCL IgA and 86% for lupus anticoagulant (table 2a).