Lymphokine production during term human pregnancy: differences between peripheral leukocytes and decidual cells

Although the fetus is considered to be an "allograft" there is little information concerning the role of lymphokines in human pregnancy. Lymphokines are polypeptides secreted by stimulated lymphocytes that direct the immune response by enabling immune effector cells to communicate with each other. To characterize lymphokine production during normal human pregnancy, we isolated peripheral leukocytes and decidual lymphocyte-like cells from women undergoing repeat cesarean section at term. After stimulation with mitogen and paternal antigen for 24 hours, culture supernatants were assayed for granulocyte-macrophage colony-stimulating factor and interleukin-2 by enzyme-linked immunosorbent assay. There was no difference in the amount of interleukin-2 produced by stimulated peripheral and decidual cells. However, granulocyte-macrophage colony-stimulating factor production by stimulated decidual lymphocyte-like cells was significantly greater than granulocyte-macrophage colony-stimulating factor produced by peripheral lymphocytes. Decidual lymphocyte-like cells produced granulocyte-macrophage colony-stimulating factor both spontaneously and after stimulation with mitogen or paternal antigen, whereas peripheral leukocytes did not. This suggests that the decidua constitutes a distinct immunologic microenvironment.