Immunological studies in recurrent spontaneous abortion: effects of immunization of women with paternal mononuclear cells on lymphocytotoxic and mixed lymphocyte reaction blocking antibodies and correlation with sharing of HLA and pregnancy outcome.

The occurrence of maternal antipaternal lymphocytotoxic antibody (LCTA), mixed lymphocyte reaction blocking factors (MLRBF) and human leukocyte antigen (HLA) antigen sharing was studied in 115 couples with unexplained repeated spontaneous abortions (RSA). Comparisons were made to the same studies done on 41 couples with explained repeated miscarriages. We found no significant difference between the patient and control group with respect to the percent of couples sharing none, one, or two or more HLA-A,-B, or -DR antigens. Examination of the occurrence of LCTA and MLRBF likewise did not reveal differences between the groups, nor did the occurrence of these antibodies on initial testing correlate with HLA disparity between couples. Women with three or more spontaneous abortions were immunized with paternal mononuclear cells (MNC) if they met at least two of the following three criteria: they shared two or more HLA antigens; their serum was negative for paternal MNC-directed LCTA; their serum did not contain maternal versus paternal MLR blocking factors. Complete HLA, LCTA and MLRBF data pre- and post-treatment are available on 60 women. Sixty-three percent of women converted to LCTA positive 6 +/- 1 weeks after immunization, and 35% of women converted from negative to positive for MLR blocking after immunization. Fifty-eight women who had all three tests done prior to immunization became pregnant after immunization. Only 50% of this selected group have experienced successful pregnancy as judged by delivery of a live-born infant. In the patients presented, successful pregnancy outcome did not correlate with HLA antigen disparity, but successful patients were more likely than aborters to have either LCTA or MLRBF prior to pregnancy (28 vs. 7%). Post-immunization conversion to LCTA positive was more prevalent in the women who aborted after immunization (74%) compared to those who had successful pregnancy (48%) while MLR blocking antibody conversion from negative to positive was the same in both groups. The data indicate that neither HLA antigen sharing nor conversion to LCTA or MLR blocking positive after paternal WBC immunization are predictors for successful pregnancy outcome. Results so far suggest that conversion to LCTA positive after immunization may have a negative influence on pregnancy outcome.