Proliferative response to recall antigens are associated with pregnancy outcome in women with a history of recurrent spontaneous abortion

Many researchers believe that the sixly percent of recurrent spontaneous abortions, unrelated to structural, infectious, or chromosomal abnormalities, are immunologically mediated. Since the fetus is a hem ial log raft, we hypothesize that immunosuppression is necessary for fetal survival. Previous studies have shown that graft survival in immunosuppressed transplant recipients is associated with lost proliferative responses to recall antigens. In this study we evaluate proliferative responses to recall antigens in three groups of women: Group 1) Non-pregnant women with a history of 3 or more spontaneous abortions, N=43; Group 2 ) Healthy women with no history of prior miscarriage who were between 6 and 12 weeks pregnant. N=IO; and Group 3) .Women, who had 3 or more prior spontaneous abortions who were between 6 and 12 weeks pregnant, N=19. Peripheral blood leukocytes were Ficoll separated from whole blood and cells were placed in culture with the recall antigens influenza and tetanus, allo antigens, and phytohemagluttanin (PHA). Cells were harvested on day 7 and a stimulation index of greater than 3 was considered a positive response. In Group !. 10/43 (24%) of non-pregnant women did not respond to recall antigens. In Group 2, 9'10 (90%) lost responsiveness to recall antigens. In Group 3, of the 10/19 (53%) of women who lost responsiveness to recall antigens there was 100% fetal survival. However in the 9/19 patients who responded to recall antigens 4/9 (44%) had fetal wastage. These findings suggest that immunosuppression. as indirectly measured by proliferation to recall antigens, is necessary for early pregnancy maintenance. Thus, in some patients, recurrent miscarriages may result from an inability to adequately induce necessary immunosuppression.