Acute atherosis. A histopathological hallmark of immune aggression?

Acute atherosis is a maternal vascular lesion observed regularly in cases of pre-eclampsia and idiopathic intrauterine growth retardation. This vasculopathy is characterized by fibrinoid necrosis of the vessel wall, an accumulation of lipid-laden macrophages, and a mononuclear perivascular infiltrate. Similar vascular lesions are seen in the decidual vessels of patients with autoimmune diseases, and in renal, cardiac and hepatic homograft rejection. Immunohistochemical studies often reveal extensive vascular deposition of IgM and complement in acute atherosis-like lesions. Granular deposition of immunoglobulins and complement within the vessel walls and mononuclear perivascular infiltrate may be a histopathological hallmark of a maternal immunological aggression against fetal tissues.