An Immunohistochemical Study of the Secretory Immune System in Human Fetal Membranes and Decidua of the First Trimester of Pregnancy

In the fetal membranes and decidua all the SIS components are present. We suggest that two SIS, maternal and fetal, participate in the formation of the barrier between a mother and the fetus. Both these systems have different origin and cellular content as well as different immune reactions.