The theory of binding and opening is supported by the observation that APS patients, for which the primary antigen site is located on DI (Iverson et al., 1998, Iverson, 2002, Reddel et al., 2000), do not present β2GPI-antibody complexes in circulating plasma (Aǧar, 2010) suggesting the epitope is not accessible in circulating forms. Here, APOH is linked to autoimmune polyendocrinopathy.