Villitis of unknown etiology, abbreviated VUE, is an inflammatory process

Inflammation

Inflammation is part of the complex biological response of vascular tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. Inflammation is a protective attempt by the organism to remove the injurious stimuli and to initiate the healing process...

 that involves the chorionic villi

Chorionic villi

Chorionic villi are villi that sprout from the chorion in order to give a maximum area of contact with the maternal blood.Embryonic blood is carried to the villi by the branches of the umbilical arteries, and after circulating through the capillaries of the villi, is returned to the embryo by the...

 (villitis) those cause (etiology) is not known. VUE is associated with recurrent miscarriage

Miscarriage

Miscarriage or spontaneous abortion is the spontaneous end of a pregnancy at a stage where the embryo or fetus is incapable of surviving independently, generally defined in humans at prior to 20 weeks of gestation...

 and intrauterine growth restriction

Intrauterine growth restriction

Intrauterine growth restriction refers to poor growth of a baby while in the mother's womb during pregnancy. The causes can be many, but most often involve poor maternal nutrition or lack of adequate oxygen supply to the fetus....

, and recurs in subsequent pregnancies.

Histopathology

Histomorphologically

Histopathology

Histopathology refers to the microscopic examination of tissue in order to study the manifestations of disease...

, VUE is characterized by a lymphocytic

Lymphocyte

A lymphocyte is a type of white blood cell in the vertebrate immune system.Under the microscope, lymphocytes can be divided into large lymphocytes and small lymphocytes. Large granular lymphocytes include natural killer cells...

 infiltrate of the chorionic villi

Chorionic villi

Chorionic villi are villi that sprout from the chorion in order to give a maximum area of contact with the maternal blood.Embryonic blood is carried to the villi by the branches of the umbilical arteries, and after circulating through the capillaries of the villi, is returned to the embryo by the...

 without a demonstrable cause. Plasma cells should be absent; the presence of plasma cells

Plasma cell

Plasma cells, also called plasma B cells, plasmocytes, and effector B cells, are white blood cells which produce large volumes of antibodies. They are transported by the blood plasma and the lymphatic system...

 suggests an infective etiology, e.g. CMV

Cytomegalovirus

Cytomegalovirus is a viral genus of the viral group known as Herpesviridae or herpesviruses. It is typically abbreviated as CMV: The species that infects humans is commonly known as human CMV or human herpesvirus-5 , and is the most studied of all cytomegaloviruses...

infection.