The role of blocking factors and antipaternal lymphocytotoxic antibodies in the success of pregnancy in patients with recurrent spontaneous abortion

Objective: To elucidate the role of mixed lymphocyte reaction blocking factors (BF) and complement-dependent antipaternal lymphocytotoxic antibodies on the outcome of pregnancy in unexplained recurrent spontaneous aborters. Design: A controlled study of immunotherapy in which the treated group was immunized with the husband's or a third party donor's lymphocytes and the control group received autologous lymphocytes. Setting: Tertiary care institution. Patients: Forty-three patients in the control group and 48 patients in the treated group. Intervention: The before and after immunization levels of BF and antipaternal lymphocytotoxic antibodies were measured. Main Outcome Measures: The existence or changing pattern of BF and antipaternal lymphocytotoxic antibodies levels before and after immunization had no influence on the pregnancy outcome in either group of patients. Conclusion: Neither BF nor antipaternal lymphocytotoxic antibodies is essential for successful pregnancy. They probably reflect the immunological response of the mother to exposure to fetal antigens.