Treatment of Recurrent Spontaneous Abortions by Immunization With Paternal Lymphocytes Induces Immunosuppression by Placental Isoferritin

Abstract
PROBLEM: The immunological mechanism leading to an effective vaccination of unexplained habitual aborters with paternal lymphocytes is not yet elucidated. Since previous studies revealed that immunosuppression by placental isoferritin (PLF) may play an important role in the down regulation of the immune system during pregnancy, it was of interest to investigate whether alloimmunization activates immunosuppression by PLF.METHOD: The immunosuppressive effect of PLF or anti‐PLF CM‐H‐9 monoclonal antibody (MAb) was studied by a one‐way mixed lymphocyte reaction (MLR) of alloimmunized women and their husbands.RESULTS: It was found that vaccination of the women with paternal lymphocytes resulted in in vitro immunosuppression by PLF as well as by CM‐H‐9 MAb, reaching the highest effect after three vaccinations (38 ± 8 and 42 ± 10%, respectively). The increase in PLF immunosuppressive effect was accompanied by the appearance of serum antipaternal human leukocyte antigen cytotoxic antibodies. However, there was no correlation between the degree of suppression and titer of antibodies. The study group was too small to reach a significant correlation between degree of immunosuppression and pregnancy outcome.CONCLUSION: Although it may be of value to measure the inhibitory effect of PLF in one‐way MLR as an index of immunosuppression, further studies are needed to establish whether it is a relevant predictor of a successful pregnancy.