TLR4 and autoimmune polyendocrinopathy: It has previously been shown that β2GPI has the ability to bind to a range of receptors including TLR4, TLR2, Annexin A2 and Ro 60.33, 34, 35, 36 A known downstream activator of TLR4 is p38 MAPK22 and therefore it could be suggested that the APS autoantibodies are mediating their pathogenic effect via this receptor.