Immunization by paternal leukocytes for prevention of primary habitual abortion: results of a matched controlled trial.

Habitual abortion is a difficult clinical problem, as no cause can be found for abortion in over 50% of patients. At the habitual abortion clinic of the Sheba Medical Center, immunological activity is tested and patients who are considered suitable are offered immunopotentiation with paternal leukocytes. Patients are only treated if they have no other cause for habitual abortion, no lupus anticoagulant and no antipaternal complement-dependent antibodies (APCA). Immunization is thought to potentiate the maternal immune response to paternal antigens encountered on the trophoblast. The production of APCA antibody indicates that an immune response has occurred. Of the 156 patients so far immunized, 109 have developed these antibodies. To date, 79 of these 156 patients have become pregnant. Sixty-seven patients (with 3-12 miscarriages each) belong to the antibody-positive group. Sixty-four of the 89 subsequent pregnancies have been carried past their previous dates of abortion. Forty-seven live births have occurred. By contrast, 12 patients have been pregnant in the antibody-negative group, of the 16 subsequent pregnancies only 6 were successful. A control group is available for comparison. This consists of patients suitable for immunization, but not immunized. Of these patients, only 11 of 30 pregnancies have been carried to term.