Immune therapy of recurrent abortion

Recurrent miscarriages are, like sporadically occurring miscarriage, often (approx. 50 %) due to chromosomal aberrations. An undefined proportion of the other half may be due to immunological incompliances. The basis for this assumption is the fact that the maternal immune system recognizes paternal antigens and rejects them. The initial hypothesis that such immune reaction is due to a high similarity between the maternal and paternal HLA systems (HLA sharing) is most likely incorrect. Nevertheless, the incomplete recognition of the fetus by the maternal immune system and the resulting insufficient protection is basis for the active immune therapy with partner or donor lymphocytes. Several placebo-controlled studies have been performed. Due to the small number of cases, results were not significant. A metaanalysis of all studies, however, proves significant effects of the active immune therapy. The risks of active immune therapy led to the development of passive immune therapy with immune globulins (IVIG). This therapy, however, is relatively expensive and obviously no more successful than the active immune therapy. In a metaanalysis of all published results, IVIG was not significantly more effective than treatment with placebo. The indication for both forms of immune therapy is given after 3 or more consecutive abortions, after exclusion of other reasons for these abortions. It appears that only primary aborting patients are suitable for active immune therapy. Athough the concept of immune therapy is still under debate, alternative concepts are not available. Hence, new therapeutic approaches are also not available.