This study looks in detail at the type of immune cells that are found in placentas with CVUE and MCI. It hypotheseses that these might be differing severities of the same underlying pathology. It also explicitly states two different ideas as to what causes CVUE/MCI – either due to the fetus responding to an infectious agent within the placenta, or the maternal immune response to the fetus.
Website: Labarrere CA, Hardin JW, Haas DM, Kassab GS. Chronic villitis of unknown etiology and massive chronic intervillositis have similar immune cell composition. Placenta 2015;36(6). doi:10.1016/j.placenta.2015.03.008.