Immunology of spontaneous abortion and hydatidiform mole.

Our study of the sequence of morphological events leading to the formation of hydatidiform mole (HM) led us to this study. Our object in this paper is to present evidence supporting our 1971 hypothesis with results obtained by various immunological methods in our laboratory, and to propose the importance of an immunoregulatory mechanism by blocking antibody (BA). Our hypothesis is that the conceptus, after the early demise of the embryo, may be dropped out in most cases as spontaneous abortion (SpA), and the trophoblast in the remaining cases continues to grow, developing into HM by an "immune selection" mechanism. Our conclusion is that the trophoblast will be damaged by immune cytotoxic mechanism through a decrease of BA in SpA, and continue to grow in HM through continuous production of BA after the demise of the embryo.