Antibodies to Trophoblasts during the Post-Partum Period

Abstract

RECENT investigation of homograft tolerance has stimulated speculation about the immunological relationship between mother and fœtus during pregnancy^1,2. Since the fœtus with its placenta is genetically different from the maternal host, it can be looked upon as a homograft tolerated by the mother for nine months. Fundamental to the support of such a concept is the demonstration of an immune response by the mother to her products of conception at some time during or after pregnancy. In human beings, the syncytiotrophoblasts are the fœtal cells in direct contact with the maternal bloodstream. They invade the bloodstream and disappear¹. It would seem, therefore, that an immune response by the mother would most likely be directed towards tropho-blasts. Although experimental homograft immunity is mediated primarily through a cellular response by the host³, the direct contact between trophoblasts and maternal blood might stimulate a humoral response as well. The large mass of trophoblastic tissue in the placenta could absorb circulating antibody effectively. This might explain previous reports of failure to detect antibodies to placenta during pregnancy^4,5. After delivery of the fœtus and placenta, the absence of this absorptive surface might allow any anti-trophoblastic antibody to remain in the bloodstream, where it could be detected by appropriate methods.