APOH and autoimmune polyendocrinopathy: The antibodies for which there is clearest evidence of a causal link to development of both thrombotic and obstetric complications in APS are IgG antibodies that can be detected either by binding to CL in the presence of β2GPI (IgG aCL) or by binding to β2GPI itself (IgG aβ2GPI) [6–9].