APOH and autoimmune polyendocrinopathy: In this respect, it is interesting to note that the reactivity of SLE and APS sera toward other negatively charged lipids such as lyso(bis)phosphatidic acid (LBPA) [27,38] could be mediated by the relatively non-specific interaction that serum proteins like β2-GPI may have with chemically different phospholipids sharing a negative charge.