Experience with Allogeneic Leukocyte Immunization (Ai) for Implantation Failure in the In‐Vitro Fertilization Program

Immunological mechanisms might contribute to the repeated implantation failure in the in‐vitro fertilization program. AI might be a valuable therapeutic option in this situation. Here we summarize our extensive experience with this immunotherapy. We conducted a retrospective analysis of all couples who were referred to our outpatients department from 1996 to 1998 for AI after two or more embryo transfers (ET). Six hundred and eighty‐six couples (89%) continued IVF/ICSI and were followed up for 2–3 years. On average patients entered AI after 3–4 IVF–ET at an age of 33 years and completed IVF/ICSI treatment after another 2 ET; 2.6 embryos per ET were transferred according to the German embryo protection law. The cumulative birth rate war 38% after IVF transfer and 42% when spontaneous pregnancies were included. Until the age of 36 years the rates of viable pregnancies and birth were improved by a quarter in the first 6 months as compared to the second half year (33.3% versus 26.3%, 26.0% versus 19.6%) and to the German IVF Registry of 1998. Couples who had undergone more than three ET before AI seemed to benefit most. Our data suggest that AI is a valuable adjuvant therapy with a temporary effect when 3–4 IVF/ICSI transfers have been unsuccessful. The underlying immunomodulatory mechanisms require further investigation.