Immunological aspects of human amniotic fluid cells: implication for normal pregnancy

Amniotic fluid cells (AFCs) are routinely obtained and expanded in vitro for prenatal diagnosis; nevertheless current knowledge about their properties is limited. The detailed mechanisms underlying normal pregnancies are yet to be discovered. The goal of this study was to identify the immunological aspects of AFCs including cytokine production and human leukocyte antigen (HLA) expression, and to discuss its implication for pregnancy. Eighty-six samples of AFCs were determined for HLA expression before and after culture. Cytokine production was measured with flow cytometry in AFC culture supernatants. Treatment of interferon (IFN)-gamma on induction of HLA-DR expression in cultured AFCs was also investigated. Data indicated that both fresh and cultured AFCs express HLA-I, HLA-G, but not HLA-DR, and the cultured AFCs predominately produce the cytokine interleukin (IL)-6. Importantly, we observed that IFN-gamma could induce HLA-DR expression on cultured AFCs in a dose-dependent manner. Taken together, our results indicated that AFCs are functionally active cells and are significant in pregnancy.