Allogenic leukocyte immunization after five or more miscarriages. Recurrent Miscarriage Immunotherapy Trialists Group.

Rather than investigate whether paternal leukocyte immunization improves the live birth rate in women with three or more abortions, we analysed the results of patients expected to have a poor outcome in a subsequent pregnancy if untreated, i.e. women with five or more abortions and no anti-paternal complement-dependent antibody (APCA) at initial testing. The analysis included the results of patients treated by us over the last 8 years and the results of randomized and non-randomized trials reported by the Recurrent Miscarriage Immunotherapy Trialists Group. Patients with a previous live birth were classified into two groups: secondary aborters if there was an initial live birth followed by miscarriages, or tertiary aborters if there were miscarriages followed by a live birth and at least three subsequent miscarriages. The results were evaluated separately for primary, secondary and tertiary aborters who demonstrated APCA activity as a result of immunization. The 107 primary aborters had double the live birth rate if immunized, with an overall benefit of 31%. The 45 tertiary aborters had an almost 3-fold increase in the live birth rate, with an absolute benefit of 50%. The number of patients needed to treat to achieve one extra live birth was three to four primary aborters or two tertiary aborters. Immunization had little beneficial effect in secondary aborters but was effective in preventing abortion in primary or tertiary aborters with five or more abortions.