[The clinical significance of OFA-I in the immunological rejection mechanism in trophoblasts].

Oncofetal Antigen-I is a membrane antigen of melanoma cells that cross-reacts with human fetal brain tissues. In this paper, from the point of view of fetal antigen, we investigated the immune response of pregnant women and the role of OFA-I in pregnancy. The results obtained are as follows. A higher prevalence of anti-OFA-I with the IA method was obtained in sera from pregnant women (50% in the 1st, 48% in 2nd and 55% in 3rd trimester). The prevalence of anti-OFA-I with the IA method was 78% (21/27) in total hydatidiform mole, 80% (8/10) in invasive mole and 86% (28/32) in choriocarcinoma patients. OFA-I was not detected in thirteen normal trophoblasts and five total mole ones by means of the IA absorption assay. With the indirect immunofluorescence method, OFA-I was found in 40% of incomplete abortions (4/10) and 28% of inevitable ones (5/18) but not found in normal trophoblasts (0/5). Specific fluorescence of OFA-I was found mainly in the syncytiotrophoblast. From these findings, we are tempted to conclude that OFA-I is not expressed on normal trophoblasts but expressed on aborted ones and that OFA-I may induce a rejection reaction in vivo to the trophoblast cells of the immunological front in aborted pregnancy.