Fetomaternal Cell Trafficking: A New Cause of Disease?

Isolation of fetal cells from maternal blood is under active investigation as a noninva-sive method of prenatal diagnosis. In the context of studying cell surface antigens ex-pressed on fetal cells we discovered that fe-tal cells from a prior pregnancy also could be detected. This led to the appreciation of the persistence of fetal cells in maternal blood for as long as 27 years postpartum, and the realization that following preg-nancy, a woman becomes a chimera. Quan-titative polymerase chain reaction analyses have shown that a term pregnancy is not re-quired for the subsequent development of fetal cell microchimerism. As many as 500,000 fetal nucleated cells are transfused following an elective first trimester termi-nation of pregnancy. The relationship be-tween fetal cell microchimerism and mater-nal disease is currently being explored. During pregnancy, fetal cells in the mater-nal skin are related to polymorphic erup-tions of pregnancy and increased fetomater-nal trafficking is detectable in cases of preeclampsia. After delivery, more male DNA of presumed fetal origin is present in the blood and skin of women with scleroder-ma as compared with healthy controls. Scleroderma is of particular interest be-cause it shows a strong female predilection and it is an autoimmune disease with clini-cal similarities to graft-versus-host disease. Fetomaternal cell trafficking provides a po-tential explanation for the increased preva-lence of autoimmune disorders in adult women following their childbearing years