Unexplained Recurrent Abortion Research Articles

Immunological and para-immunological mechanisms in spontaneous abortion: recent insights and future directions

Unexplained spontaneous abortion in humans is currently thought to be related to genetic or immunologic factors. Animal models of spontaneous abortion have been used to try to gain some insight into the problems in humans. From studies of animal models there is increasing evidence that a variety of mechanisms may initiate pregnancy failure and participation of immunologic effectors may be a secondary event. Recent studies indicate that murine abortion that occurs spontaneously (without deliberate immunization by the investigator) may be initiated by para-immunologic host effector cells such as NK cells, macrophages and their toxins that possess selective toxicity which is not antigen-specific. The potential importance of local non-specific suppressive mechanisms in the uterus is also highlighted by their ability to block non-specific paraimmune effector cell activation, and by their potential relationship to growth factors in decidual supernatants that promote placental cell growth in vitro. Levels of non-specific suppression do not appear low when fetal death can be attributed to a genetic mutation. The concept that different tissue components of (Tsutsumi and Oka, 1987). In T cell deficient mice, failure of xenogeneic trophoblast to recruit suppressor cells could also mean failure to recruit non-T cells that elaborate growth factors. Failure of allogeneic trophoblast adequately to recruit cells that elaborate suppressor/growth factors could lead to defective placental development and hence to embryo death.A model summarizing putative host mechanisms damaging fetal and trophoblast tissue is shown in Fig. 1. The data as currently interpreted strongly suggest that further progress will result from investigation of para-immunologic mechanisms in models of spontaneous abortion where the pathogenesis remains unclear. From studies on experimental animal systems one may eventually understand unexplained recurrent abortion in humans, a condition which at present most likely reflects a variety of different pathogenetic mechanisms.

A Study on Unexplained Recurrent Aborters from the Standpoint of Cellular Immunity

A Study on Unexplained Recurrent Aborters from the Standpoint of Cellular Immunity

Production of blocking antibodies by vaccination with husband's lymphocytes in unexplained recurrent aborters: the role in successful pregnancy.

To elucidate an immunological mechanism in terms of the effectiveness of vaccination of the unexplained habitual aborters with their husband's lymphocytes, 20 patients were selected as the experimental group, and 10 fertile couples were selected as the control group. Subjects were studied by mixed lymphocyte reaction-blocking assay so as to determine whether they had blocking antibodies (BAbs) in their sera. In the experimental group, BAb levels were found to be significantly lower as compared to the ten control multiparous wives; 17 cases (85%) of them were proved not to have sufficient BAbs. Significant sharing of HLA-D/DR antigens was observed in experimental couples. Then, 10 out of 17 patients with evidence of no produced BAbs were vaccinated with their husband's lymphocytes, and all of them were observed to produce BAbs within three vaccinations. After vaccination, seven out of ten patients have so far become pregnant, five of these pregnancies have been successful, with evidence of continuing production of BAbs. In conclusion, vaccination of the patients with husband's lymphocytes was found to stimulate a production of BAbs, and it was thus strongly suggested that this may lead to their production in a subsequent pregnancy, which would allow its success.

Histocompatibility in couples with recurrent spontaneous abortion and normal fertility

Histocompatibility between husband and wife at the HLA locus has been suggested as a determinant of recurrent spontaneous abortion. We measured the incidence of HLA antigen sharing within 12 couples with histories of unexplained recurrent abortion and in a fertile control population of 77 couples. In the recurrent abortion group, 6 of 12 (50%) of the couples shared no HLA antigens, whereas only 3 of 12 (25%) shared one antigen, 1 of 12 (8.3%) shared two antigens, and 2 of 12 (17%) shared three antigens. In the fertile group, 27 of 77 (35.1%) shared no antigens, 33 of 77 (42.8%) shared one antigen, 14 of 77 (18.2%) shared two antigens, 2 of 77 (2.6%) shared three antigens, and 1 of 77 (1.3%) shared four antigens. In 50 of these control couples who were available for complete reproductive histories, there were no significant correlations between the incidence of antigen sharing and the numbers of offspring, the incidence of spontaneous abortion, or infertility problems. Six of the women in the recurrent abortion group became pregnant during the study. Three of these (50%) delivered live infants independent of the degree of antigen sharing and without the benefit of immunologic treatment. Therefore, the degree of HLA antigen sharing did not define a population with increased pregnancy wastage or predict subsequent pregnancy outcome.