Comparison of the proportions of leukocytes in early and term human decidua.

The percentages of cells expressing immune markers were determined with immunohistochemistry and flow cytometry in early and term human decidua. Although we found no variation in the proportion of cells of bone marrow origin (CD45+), the percentages of T cells and CD16+ lymphocytes were significantly higher in term decidua. On the contrary, CD56+ lymphocytes, the most abundant leukocyte type in early decidua, decreased at term. These variations may reflex the immunological adaptations of decidua during pregnancy.