Biological implications of bi-directional fetomaternal cell traffic: a summary of a National Institute of Child Health and Human Development-sponsored conference.

OBJECTIVE: The National Institute of Child Health and Human Development (NICHD) held a workshop on 27-28 July 2000 to bring together investigators working in the field of fetomaternal cellular and nucleic acid trafficking with the hope that this would stimulate further research into the biological implications of such phenomena.
METHODS: Invited speakers from all over the world presented their latest (unpublished) data. The conference proceedings were delayed until the present time to allow independent publication of the primary data. RESULTS AND
CONCLUSIONS: Bi-directional fetomaternal trafficking of cells and nucleic acids during pregnancy is now well established, through the use of molecular techniques including conventional and real-time polymerase chain reaction, as well as fluorescence in situ hybridization. In addition, human leukocyte antigen (HLA) is deposited in the skin of pregnant women. Fetomaternal trafficking is increased in some complications of pregnancy, such as pre-eclampsia, polyhydramnios, polymorphic eruption of pregnancy, preterm labor and specific fetal chromosome aneuploidies. Maternal cells and nucleic acids have been documented in umbilical cord blood and in autopsy tissue of non-transfused neonates. Fetal cells persist postpartum and may be associated with the development of disorders such as scleroderma, lichen planus, lupus and thyroid disease. The extent of fetomaternal trafficking may be affected by three generational HLA relationships. Thus, the consequences of pregnancy extend beyond gestation.