Immunological studies of the placenta in maternal connective tissue disease.

Maternal connective tissue disease is an important cause of second-trimester fetal loss. In order to assess the pathological changes in the placenta in maternal connective tissue disease, we reviewed the clinical histories and performed histologic and immunofluorescence studies on nine placentas: five from mothers with systemic lupus erythematosus (SLE), two from mothers with mixed connective tissue disease (MCTD), one from a mother with rheumatoid arthritis (RA), and one from a mother without prior known connective tissue disease. Excessive intervillous fibrin deposition and infarction were noted in all cases. Immunofluorescent and immunoperoxidase studies showed deposits of fibrinogen, IgG, IgM, IgA, and complement 3 (C3) localized to the trophoblast basement membrane (TBM). Electron microscopy documented thickening of the trophoblast basal lamina in three SLE placentas examined. The use of immunofluorescence may be enhanced further if antitrophoblast antibodies can be linked to placental compromise.