Maternal immune responses induced by the immunotherapy for patients with recurrent spontaneous abortions

: The mechanism of the beneficial effect of immunotherapy for human reproductive wastage remains to be elucidated. The induction of blocking antibodies such as anti-HLA class II antibodies and anti-idiotypic antibodies was investigated as the mechanism of specific immunosuppression in pregnancy. We reported that changes in a mixed lymphocyte culture (MLC), T-cell subsets and generation of anti-idiotypic antibodies after immunotherapy compared to before. MLC was significantly (p less than 0.001) inhibited after the immunization. The mean inhibition rate was 50.5%, suggesting that MLR blocking antibodies were induced by immunotherapy. We demonstrated that this blocking effect was specific to the husband, because the inhibition of one-way MLC reactions which were set up with responding maternal lymphocytes and MMC-treated stimulating lymphocytes of third parties were significantly low (p less than 0.05) compared to stimulation with paternal lymphocytes. The binding of autoantibodies to alloactivated maternal lymphoblasts against the paternal lymphocytes was detected in post-immunization cases in two-color flow-cytometric experiments. This strongly suggests that anti-idiotypic antibodies were induced by the immunotherapy. The percentage of cytotoxic T cells was significantly decreased (p less than 0.05) and the percentage of suppressor T cells was significantly increased (p less than 0.01) after the immunotherapy, suggesting that a cell-mediated immune response was induced by the immunotherapy.