MPL and systemic lupus erythematosus: Autoantibodies targeting antigenic glycoproteins on the platelet membrane are central to the destruction of platelets in SLE.23–25 In some cases other autoantibodies such as antiphospholipid antibodies26,27 and autoantibodies against thrombopoietin (TPO) or TPO receptor (c-mpl) are identified.28–30 Antibody-coated platelets are subsequently removed by splenic and other reticular macrophages, through binding on their surface Fc gamma receptor.