| Research Abstract |
We had treated 68 patients with unexplained recurrent spontaneous abortion from 1985 to 1991. Fifty of sixty eight patients receiving Immunotherapy with husband's lymphocytes had conceived. Forty four patients were successful and 6 patients had abortion again. Abortion-preventing rate was 88% (1).
To investigate the mechanisms of immunotherapy for these patients, peripheral. blood mononuclear cells (PBMC) and sera were stored before and after immunotherapy. Delayd type hypersensitivity (DTH) skin reaction as in vivo assay and HLA typing, mixed lymphocyte reaction (MLR) and NK activity as in vitro assay were studied.
Some previous reports showed increased sharing of HLA antigens between spouses in aborting couples. However, other authers have not been able to demonstrate increased HLA sharing in these couples. In our study the patlents did not significantly share HLA antigens in any locus with their mates as compared with control pairs (1).
It is considered that monocytes, dendritic cells
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and B cells are important in induction phase of immunotherapy since these cells have allo-antigen presenting (allo-APC) function. However, we clarified that T cells which are major cell population in PBMC had also allo-APC function (2), suggesting that husband's T cells might be involved in mechanisms of immunosuppression induced by immunotherapy.
Delayd type hupersensitivity (DTH) reactions induced by injection to wife's forearm with husband's PBMC were reduced in 75% of pregnant patients after immunotherapy. Mixed lymphocyte reactions (MLR) of wife to husband were also reduced in 70% of pregnant patients. Changes of DTH ractions were associated with those of MLR (1).
To investigate immunosuppressive mechanisms of immunotherapy, we firstly studied which cell fractions suppress the MLR.Depletion of glass-adherent cell in wife's PBMC after immunotherapy enhanced MLR of wife to husband. In this experiment the addition of adherent cells suppressed the enhanced MLR(3). These data suggest that the galss-adherent population stimulated by immunotherapy may induce immunosuppression in decidua.
We elucidated anti-idiotypic T cell network in peripheral blood of normal volunteer (4,5). Initially, we established an allo-reactive, HLA class II specific CD4 positive T cell clone, TM-14. Subsequently, we esablished a CD8 positive T cell line, AI-1 and a CD4 positive T cell line, AI-2, that specifically proliferated to TM-14 T cell clone. The CD8 positive AI-1 T cell line showed cytotoxicity against TM14 but not against other T cell clone and T cell blasts from the same donor (4). The CD4 positive AI-2 T cell line showed suppressive activity but not cytotoxic activity to the TM-14 T cell clone (5). These T-T interactions may be involved in downregulation of local T cell responses in feto-maternal interface.
Recently it is elucidated that trophoblast cells did not express classical HLA antigenns on the cell surface. It seems that T cells which recognize alloantigens in the decidua are not so essential. There are some evidence in murine systems that decidual NK cells are primarlly involved in spontaneous abortions. We studied NK cell activity in aborting patients. Successful patients showed significant decrease of NK cell activity after immunotherapy, whereas nonpregnant patients, who did not become pregnant more than 12 months after immunotherapy, showed significant increase of NK activity (6,7). Therefore, it seemed that the change of NK cell activity was responsible for clinical outcome. However, the increase of NK cell activity which allows to infertile is probably a side effect of immunotherapy. It is necessary to find parameters predicting infertility after immunotherapy. Less
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