The diagnosis of APS requires the presence of at least one clinical event (either an objectively confirmed thrombotic event and/or pregnancy complication) and detection of one or more aPL (lupus anticoagulant [LA], IgG/IgM anticardiolipin [aCL], and/or IgG/IgM anti-β2 glycoprotein-1 [aβ2GPI]). Here, CD40LG is linked to autoimmune polyendocrinopathy.